TMC246_06中文资料_数据手册_规格书

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

1

TMC 246/A – DATA SHEET

High Current Microstep Stepper Motor Driver

with sensorless stall detection, protection /

diagnosis and SPI Interface

TRINAMIC^®Motion Control GmbH & Co KG

Sternstraße 67

D – 20357 Hamburg

GERMANY

T +49 - (0) 40 - 51 48 06 - 0

F +49 - (0) 40 - 51 48 06 - 60

WWW.TRINAMIC.COM

INFO@TRINAMIC.COM

Features

The TMC246 / TMC246A (1) is a dual full bridge driver IC for bipolar stepper motor control

applications. The integrated unique sensorless stall detection (pat. pend.) StallGuard™ makes it a

good choice for applications, where a reference point is needed, but where a switch is not desired. Its

ability to predict an overload makes the TMC246 an optimum choice for drives, where a high reliability

is desired. The TMC246 is realized in a HVCMOS technology combined with Low-RDS-ON high

efficiency MOSFETs (pat. pend.). It allows to drive a coil current of up to 1500mA even at high

environment temperatures. Its low current consumption and high efficiency together with the miniature

package make it a perfect solution for embedded motion control and for battery powered devices.

Internal DACs allow microstepping as well as smart current control. The device can be controlled by a

serial interface (SPI™ⁱ) or by analog / digital input signals. Short circuit, temperature, undervoltage

and overvoltage protection are integrated.

•

Sensorless stall detection StallGuard™ and load measurement integrated

Control via SPI with easy-to-use 12 bit protocol or external analog / digital signals

Short circuit, overvoltage and overtemperature protection integrated

Status flags for overcurrent, open load, over temperature, temperature pre-warning, undervoltage

Integrated 4 bit DACs allow up to 16 times microstepping via SPI, any resolution via analog

control

•

Mixed decay feature for smooth motor operation

Slope control user programmable to reduce electromagnetic emissions

Chopper frequency programmable via a single capacitor or external clock

Current control allows cool motor and driver operation

7V to 34V motor supply voltage (A-type)

Up to 1500mA output current and more than 800mA at 105°C

3.3V or 5V operation for digital part

Low power dissipation via low RDS-ON power stage

Standby and shutdown mode available

(1) The term TMC246 in this datasheet always refers to the TMC246A and the TMC246. The major

differences in the older TMC246 are explicitly marked with “non-A-type”. The TMC246A brings a

number of enhancements and is fully backward compatible to the TMC246.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

2

FEATURES ............................................................................................................................................1

PINNING.................................................................................................................................................5

PACKAGE CODES...................................................................................................................................5

PQFP44 DIMENSIONS ..........................................................................................................................6

APPLICATION CIRCUIT / BLOCK DIAGRAM .....................................................................................7

PIN FUNCTIONS.....................................................................................................................................7

LAYOUT CONSIDERATIONS...............................................................................................................8

CONTROL VIA THE SPI INTERFACE..................................................................................................9

SERIAL DATA WORD TRANSMITTED TO TMC246......................................................................................9

SERIAL DATA WORD TRANSMITTED FROM TMC246..................................................................................9

TYPICAL WINDING CURRENT VALUES.....................................................................................................10

BASE CURRENT CONTROL VIA INA AND INB IN SPI MODE......................................................................10

CONTROLLING THE POWER DOWN MODE VIA THE SPI INTERFACE...........................................................10

OPEN LOAD DETECTION .......................................................................................................................11

STANDBY AND SHUTDOWN MODE..........................................................................................................11

POWER SAVING ...................................................................................................................................11

STALL DETECTION ............................................................................................................................12

USING THE SENSORLESS LOAD MEASUREMENT .....................................................................................12

IMPLEMENTING SENSORLESS STALL DETECTION ....................................................................................12

PROTECTION FUNCTIONS................................................................................................................13

OVERCURRENT PROTECTION AND DIAGNOSIS........................................................................................13

OVERTEMPERATURE PROTECTION AND DIAGNOSIS ................................................................................13

OVERVOLTAGE PROTECTION AND ENN PIN BEHAVIOR ...........................................................................13

CHOPPER PRINCIPLE........................................................................................................................14

CHOPPER CYCLE / USING THE MIXED DECAY FEATURE...........................................................................14

BLANK TIME ........................................................................................................................................14

BLANK TIME SETTINGS .........................................................................................................................14

CLASSICAL NON-SPI CONTROL MODE (STAND ALONE MODE) ................................................15

PIN FUNCTIONS IN STAND ALONE MODE.................................................................................................15

INPUT SIGNALS FOR MICROSTEP CONTROL IN STAND ALONE MODE..........................................................15

CALCULATION OF THE EXTERNAL COMPONENTS......................................................................16

SENSE RESISTOR................................................................................................................................16

EXAMPLES FOR SENSE RESISTOR SETTINGS..........................................................................................16

HIGH SIDE OVERCURRENT DETECTION RESISTOR R_SH............................................................................16

MAKING THE CIRCUIT SHORT CIRCUIT PROOF.........................................................................................17

OSCILLATOR CAPACITOR .....................................................................................................................18

TABLE OF OSCILLATOR FREQUENCIES...................................................................................................18

PULLUP RESISTORS ON UNUSED INPUTS ...............................................................................................18

SLOPE CONTROL RESISTOR ................................................................................................................19

EXAMPLE FOR SLOPE SETTINGS ...........................................................................................................19

ABSOLUTE MAXIMUM RATINGS......................................................................................................20

ELECTRICAL CHARACTERISTICS ...................................................................................................20

OPERATIONAL RANGE .........................................................................................................................20

DC CHARACTERISTICS ........................................................................................................................21

AC CHARACTERISTICS ........................................................................................................................22

THERMAL PROTECTION........................................................................................................................22

THERMAL CHARACTERISTICS ...............................................................................................................23

TYPICAL POWER DISSIPATION AT HIGH LOAD / HIGH TEMPERATURE........................................................23

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

3

SPI INTERFACE TIMING.....................................................................................................................24

PROPAGATION TIMES ..........................................................................................................................24

USING THE SPI INTERFACE..................................................................................................................24

SPI FILTER.........................................................................................................................................24

ESD PROTECTION..............................................................................................................................25

APPLICATION NOTE: EXTENDING THE MICROSTEP RESOLUTION ...........................................26

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

4

Life support policy

TRINAMIC Motion Control GmbH & Co KG does not

authorize or warrant any of its products for use in life

support systems, without the specific written consent

of TRINAMIC Motion Control GmbH & Co KG.

Life support systems are equipment intended to

support or sustain life, and whose failure to perform,

when properly used in accordance with instructions

provided, can be reasonably expected to result in

personal injury or death.

Information given in this data sheet is believed to be

accurate and reliable. However no responsibility is

assumed for the consequences of its use nor for any

infringement of patents or other rights of third parties,

which may result form its use.

Specifications subject to change without notice.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

5

Pinning

1

2

33

32

31

30

29

28

27

26

25

24

23

ANN

OA1

VSA

OA2

BL2

OB1

VSB

OB2

3

4

5

TMC 246 / 236A

QFP44

6

7

OA1

BRA

OA2

OB1

BRB

OB2

8

9

10

11

Package codes

Type

Package

Temperature range Lead free (ROHS)

Code/marking

TMC246A

TMC246

PQFP44

automotive (1)

Yes

TMC246A-PA

From date code 30/04 TMC246-PA

(1) ICs are not tested according to automotive standards, but are usable within the complete

automotive temperature range.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

6

PQFP44 Dimensions

REF

MIN.

MAX.

A

12

10

1

I

C

D

E

F

G

H

I

-

1.6

0.2

C

0.09

0.05

0.30

0.45

0.15

0.45

0.75

K

L

0.8

0

0.08

All dimensions are in mm.

L: Co-planarity of pins

H

K

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

7

Application Circuit / Block Diagram

+V_M

220nF

100µF

R_SH

BL1

BL2

VS

TMC246

VT

OSC

VSA

OSC

1nF

VCC

P

N

P

N

Under-

voltage

OA1

OA2

100nF

Coil A

Tem-

perature

BRA

SRA

R_S

0

1

[MDBN] SCK

4

DAC

[PHA]

SDI

INA

INB

REFSEL

VREF

[ERR] SDO

[PHB] CSN

1

0

SRB

BRB

R_S

N

P

N

P

OB1

OB2

ENN

Coil B

VCC/2

REFSEL

VSB

SPE

ANN

AGND

GND

SLP

[MDAN]

stand alone mode

R_SLP

[...]: function in stand alone mode

Pin Functions

Function

Motor supply voltage

Function

VS

VT

Short to GND detection comparator –

connect to VS if not used

VCC

3.0-5.5V supply voltage for analog GND

and logic circuits

Digital / Power ground

AGND

Analog ground (Reference for SRA, OSC

SRB, OSC, SLP, INA, INB, SLP)

Oscillator capacitor or external clock

input for chopper

INA

Analog current control phase A

Clock input of serial interface

INB

Analog current control input phase B

SCK

SDO

Data output of serial interface (tri-

state)

SDI

Data input of serial interface

CSN

Chip select input of serial interface

ENN

Device enable (low active), and SPE

overvoltage shutdown input

Enable SPI mode (high active). Tie to

GND for non-SPI applications

ANN

Enable analog current control via SLP

INA and INB (low active)

Slope control resistor.

BL1, BL2

Digital blank time select

SRA, SRB Bridge A/B current sense resistor input

OB1, OB2 Output of full-bridge B

OA1, OA2 Output of full-bridge A

VSA, VSB Supply voltage for bridge A/B

BRA, BRB Bridge A/B sense resistor

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

8

Layout Considerations

For optimal operation of the circuit a careful board layout is important, because of the combination of

high current chopper operation coupled with high accuracy threshold comparators. Please pay special

attention to a massive grounding. Depending on the required motor current, either a single massive

ground plane or a ground plane plus star connection of the power traces may be used. The schematic

shows how the high current paths can be routed separately, so that the chopper current does not flow

through the system’s GND-plane. Tie the TMC246’s AGND and GND to the GND plane. Additionally,

use enough filtering capacitors located near to the board’s power supply input and small ceramic

capacitors near to the power supply connections of the TMC246. Use low inductance sense resistors,

or add a ceramic capacitor in parallel to each resistor to avoid high voltage spikes. In some

applications it may become necessary to introduce additional RC-filtering into the VT and SRA / SRB

line, as shown in the schematic, to prevent spikes from triggering the short circuit protection or the

chopper comparator.

Be sure to connect all pins of the PQFP package for each of the double/quad output pins externally.

Each two of these output pins should be treated as if they were fused to a single wide pin (as shown in

the drawing). Each two pins are used as cooling fin for one of the eight integrated output power

transistors. Use massive motor current traces on all these pins and multiple vias, if the output trace is

changed to a different layer near the package.

A symmetrical layout on all of the OA and OB pins is required, to ensure proper heat dissipation on all

output transistors. Otherwise proper function of the thermal protection can not be guaranteed!

A multi-layer PCB shows superior thermal performance, because it allows usage of a massive GND

plane, which will act as a heat spreader. The heat will be coupled vertically from the output traces to

the GND plane, since vertical heat distribution in PCBs is quite effective. Heat dissipation can be

improved by attaching a heat sink to the package directly.

Please be aware, that long or thin traces to the sense resistors may add substantial resistance and

thus reduce output current. The same is valid for the high side shunt resistor. Use short and straight

traces to avoid parasitic inductivities, because these can generate large voltage spikes and EMV

problems.

optional voltage

divider

VS

100nF

R_DIV

VT

100R

+VM

GND

VSA

VSB

BRA

BRB

SRA

SRB

TMC236/

TMC246

C_VM

optional filter

100R

R_SA

R_SB

100R

3.3 -

10nF

GND

AGND

GND-

Plane

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

9

Control via the SPI Interface

The SPI data word sets the current and polarity for both coils. By applying consecutive values,

describing a sine and a cosine wave, the motor can be driven in microsteps. Every microstep is

initiated by its own telegram. Please refer to the description of the analog mode for details on the

waveforms required. The SPI interface timing is described in the timing section. We recommend the

TMC428 to automatically generate the required telegrams and motor ramps for up to three motors.

Serial data word transmitted to TMC246

(MSB transmitted first)

Bit Name Function

Remark

11 MDA

10 CA3

mixed decay enable phase A “1” = mixed decay

current bridge A.3

current bridge A.2

current bridge A.1

current bridge A.0

polarity bridge A

MSB

9

8

7

6

5

4

3

2

1

0

CA2

CA1

CA0

PHA

MDB

CB3

CB2

CB1

CB0

PHB

LSB

“0” = current flow from OA1 to OA2

mixed decay enable phase B “1” = mixed decay

current bridge B.3

current bridge B.2

current bridge B.1

current bridge B.0

polarity bridge B

MSB

LSB

“0” = current flow from OB1 to OB2

Serial data word transmitted from TMC246

(MSB transmitted first)

Bit Name Function

Remark

11 LD2

10 LD1

load indicator bit 2

load indicator bit 1

load indicator bit 0

always “1”

MSB

9

8

7

6

5

4

3

2

1

0

LD0

1

LSB

OT

overtemperature

“1” = chip off due to overtemperature

“1” = prewarning temperature exceeded

“1” = undervoltage on VS

OTPW temperature prewarning

UV driver undervoltage

OCHS overcurrent high side

3 PWM cycles with overcurrent within 63 PWM cycles

no PWM switch off for 14 oscillator cycles

OLB

OLA

OCB

OCA

open load bridge B

open load bridge A

overcurrent bridge B low side 3 PWM cycles with overcurrent within 63 PWM cycles

overcurrent bridge A low side 3 PWM cycles with overcurrent within 63 PWM cycles

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

10

Typical winding current values

Current setting Percentage of Typical trip voltage of the current sense comparator

current

(internal reference or analog input voltage of 2V is used)

CA3..0 / CB3..0

0000

0001

0010

...

0%

0 V

(bridge continuously in slow decay condition)

6.7%

13.3%

...

23 mV

45 mV

1110

1111

93.3%

100%

317 mV

340 mV

The current values correspond to a standard 4 Bit DAC, where 100%=15/16. The contents of all

registers is cleared to “0” on power-on reset or disable via the ENN pin, bringing the chip to a low

power standby mode. All SPI inputs have Schmitt-Trigger function.

Base current control via INA and INB in SPI mode

In SPI mode, the IC can use an external reference voltage for each DAC. This allows the adaptation to

different motors. This mode is enabled by tying pin ANN to GND. A 2.0V input voltage gives full scale

current of 100%. In this case, the typical trip voltage of the current sense comparator is determined by

the input voltage and the DAC current setting (see table above) as follows:

V

_TRIP,A= 0.17 V_INA× “percentage SPI current setting A”

_TRIP,B= 0.17 V_INB× “percentage SPI current setting B”

A maximum of 3.0V V_INis possible. Multiply the percentage of base current setting and the DAC table

to get the overall coil current. It is advised to operate at a high base current setting, to reduce the

effects of noise voltages. This feature allows a high resolution setting of the required motor current

using an external DAC or PWM-DAC (see schematic for examples).

using PWM signal

8 level via R2R-DAC

2 level control

R1

INA

INB

µC-

PWM

µC-

Port .2

47K

100K

100nF

µC-

Port .1

10nF

AGND

ANN

µC-

Port .0

µC-

Port

Controlling the power down mode via the SPI interface

Bit

11

10

9

8

7

6

5

4

3

2

1

0

Standard

function

Control

word

MxA CA3 CA2 CA1 CA0 PhA MxB CB3 CB2 CB1 CB0 PhB

-

0

-

0

-

function

Enable standby mode and

clear error flags

Programming current value “0000” for both coils at a time clears the overcurrent flags and switches

the TMC246 into a low current standby mode with coils switched off.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

11

Open load detection

Open load is signaled, whenever there are more than 14 oscillator cycles without PWM switch off.

Note that open load detection is not possible while coil current is set to “0000”, because the chopper is

off in this condition. The open load flag will then always be read as inactive (“0”). During overcurrent

and undervoltage or overtemperature conditions, the open load flags also become active!

Due to their principle, the open load flags not only signal an open load condition, but also a torque loss

of the motor, especially at high motor velocities. To detect only an interruption of the connection to the

motor, it is advised to evaluate the flags during stand still or during low velocities only (e.g. for the first

or last steps of a movement).

Standby and shutdown mode

The circuit can be put into a low power standby mode by the user, or, automatically goes to standby

on Vcc undervoltage conditions. Before entering standby mode, the TMC246 switches off all power

driver outputs. In standby mode the oscillator becomes disabled and the oscillator pin is held at a low

state. The standby mode is available via the interface in SPI-mode and via the ENN pin in non-SPI

mode.

The shutdown mode even reduces supply current further. It can only be entered in SPI-mode by

pulling the ENN pin high. In shutdown additionally all internal reference voltages become switched off

and the SPI circuit is held in reset.

Power saving

The possibility to control the output current can dramatically save energy, reduce heat generation and

increase precision by reducing thermal stress on the motor and attached mechanical components.

Just reduce motor current during stand still: Even a slight reduction of the coil currents to 70% of the

current of the last step of the movement, halves power consumption! In typical applications a 50%

current reduction during stand still is reasonable.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

12

Stall Detection

Using the sensorless load measurement

The TMC246 provides a patented sensorless load measurement, which allows a digital read out of the

mechanical load on the motor via the serial interface. To get a readout value, just drive the motor

using sine commutation and mixed decay switched off. The load measurement then is available as a

three bit load indicator during normal motion of the motor. A higher mechanical load on the motor

results in a lower readout value. The value is updated once per fullstep.

The load detection is based on the motor’s back EMF, thus the level depends on several factors:

-

Motor velocity: A higher velocity leads to a higher readout value

Motor resonance: Motor resonances cause a high dynamic load on the motor, and thus

measurement may give unsatisfactory results.

-

Motor acceleration: Acceleration phases also produce dynamic load on the motor.

Mixed decay setting: For load measurement mixed decay has to be off for some time before

the zero crossing of the coil current. If mixed decay is used, and the mixed decay period is

extended towards the zero crossing, the load indicator value decreases.

Implementing sensorless stall detection

The sensorless stall detection typically is used, to detect the reference point without the usage of a

switch or photo interrupter. Therefore the actuator is driven to a mechanical stop, e.g. one end point in

a spindle type actuator. As soon as the stop is hit, the motor stalls. Without stall detection, this would

give an audible humming noise and vibrations, which could damage mechanics.

To get a reliable stall detection, follow these steps:

1. Choose a motor velocity for reference movement. Use a medium velocity which is far enough

away from mechanical resonance frequencies. In some applications even motor start / stop

frequency may be used. With this the motor can stop within one fullstep if a stall is detected.

2. Use a sine stepping pattern and switch off mixed decay (at least 1 to 3 microsteps before zero

crossing of the wave). Monitor the load indicator during movement. It should show a stable

readout value in the range 3 to 7 (L_MOVE). If the readout is high (>5), the mixed decay portion

may be increased, if desired.

3. Choose a threshold value L_STALLbetween 0 and L_MOVE- 1.

4. Monitor the load indicator during each reference search movement, as soon as the desired

velocity is reached. Readout is required at least once per fullstep. If the readout value at one

fullstep is below or equal to L_STALL, stop the motor. Attention: Do not read out the value within

one chopper period plus 8 microseconds after toggling one of the phase polarities!

5. If the motor stops during normal movement without hitting the mechanical stop, decrease

L_STALL. If the stall condition is not detected at once, when the motor stalls, increase L_STALL

.

v(t)

v_max

t

load

indicator

acceleration

constant velocity

stall

max

L_MOVE

L_STALL

stall threshold

min

t

acceleration

jerk

stall detected!

vibration

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

13

Protection Functions

Overcurrent protection and diagnosis

The TMC246 uses the current sense resistors on the low side to detect an overcurrent: Whenever a

voltage above 0.61V is detected, the PWM cycle is terminated at once and all transistors of the bridge

are switched off for the rest of the PWM cycle. The error counter is increased by one. If the error

counter reaches 3, the bridge remains switched off for 63 PWM cycles and the error flag is read as

“active”. The user can clear the error condition in advance by clearing the error flag. The error counter

is cleared, whenever there are more than 63 PWM cycles without overcurrent. There is one error

counter for each of the low side bridges, and one for the high side. The overcurrent detection is

inactive during the blank pulse time for each bridge, to suppress spikes which can occur during

switching.

The high side comparator detects a short to GND or an overcurrent, whenever the voltage between

VS and VT becomes higher than 0.15 V at any time, except for the blank time period which is logically

ORed for both bridges. Here all transistors become switched off for the rest of the PWM cycle,

because the bridge with the failure is unknown.

The overcurrent flags can be cleared by disabling and re-enabling the chip either via the ENN pin or

by sending a telegram with both current control words set to “0000”. In high side overcurrent

conditions the user can determine which bridge sees the overcurrent, by selectively switching on only

one of the bridges with each polarity (therefore the other bridge should remain programmed to

“0000”).

Overtemperature protection and diagnosis

The circuit switches off all output power transistors during an overtemperature condition. The over-

temperature flag should be monitored to detect this condition. The circuit resumes operation after cool

down below the temperature threshold. However, operation near the overtemperature threshold

should be avoided, if a high lifetime is desired.

Overvoltage protection and ENN pin behavior

During disable conditions the circuit switches off all output power transistors and goes into a low

current shutdown mode. All register contents is cleared to “0”, and all status flags are cleared. The

circuit in this condition can also stand a higher voltage, because the voltage then is not limited by the

maximum power MOSFET voltage. The enable pin ENN provides a fixed threshold of ½ V_CCto allow a

simple overvoltage protection up to 40V using an external voltage divider (see schematic).

+V_M

for switch off at 26 - 29V:

at VCC=5V: R1=100K; R2=10K

at VCC=3.3V: R1=160K; R2=10K

ENN

µC-Port (opt.)

low=Enable,

high=Disable

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

14

Chopper Principle

Chopper cycle / Using the mixed decay feature

The TMC246 uses a quiet fixed frequency chopper. Both coils are chopped with a phase shift of 180

degrees. The mixed decay option is realized as a self stabilizing system (pat. fi.), by shortening the

fast decay phase, if the ON phase becomes longer. It is advised to enable the mixed decay for each

phase during the second half of each microstepping half-wave, when the current is meant to

decrease. This leads to less motor resonance, especially at medium velocities. With low velocities or

during standstill mixed decay should be switched off. In applications requiring high resolution, or using

low inductivity motors, the mixed decay mode can also be enabled continuously, to reduce the

minimum motor current which can be achieved. When mixed decay mode is continuously on or when

using high inductivity motors at low supply voltage, it is advised to raise the chopper frequency to

36kHz, because the half chopper frequency could be audible under these conditions.

target current phase A

actual current phase A

on

slow decay

on

fast decay

slow decay

oscillator clock

resp. external clock

mixed decay disabled

mixed decay enabled

When polarity is changed on one bridge, the PWM cycle on that bridge becomes restarted at once.

Fast decay switches off both upper transistors, while enabling the lower transistor opposite to the

selected polarity. Slow decay always enables both lower side transistors.

Blank Time

The TMC246 uses a digital blanking pulse for the current chopper comparators. This prevents current

spikes, which can occur during switching action due to capacitive loading, from terminating the

chopper cycle. The lowest possible blanking time gives the best results for microstepping: A long

blank time leads to a long minimum turn-on time, thus giving an increased lower limit for the current.

Please remark, that the blank time should cover both, switch-off time of the lower side transistors and

turn-on time of the upper side transistors plus some time for the current to settle. Thus the complete

switching duration should never exceed 1.5µs.

The TMC246 allows to adapt the blank time to the load conditions and to the selected slope in four

steps (the effective resulting blank times are about 200ns shorter in the non-A-type):

Blank time settings

BL2

BL1

Typical blank time

GND GND 0.6 µs

GND

VCC

VCC 0.9 µs

GND 1.2 µs

VCC 1.5 µs

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

15

Classical non-SPI control mode (stand alone mode)

The driver can be controlled by analog current control signals and digital phase signals. To enable this

mode, tie pin SPE to GND. In this mode, the SPI interface is disabled and the SPI input pins have

alternate functions. The internal DACs are forced to “1111”.

Pin functions in stand alone mode

Stand alone Function in stand alone mode

mode name

SPE

ANN

SCK

SDI

(GND)

MDAN

MDBN

PHA

Tie to GND to enable stand alone mode

Enable mixed decay for bridge A (low = enable)

Enable mixed decay for bridge B (low = enable)

Polarity bridge A (low = current flow from output OA1 to OA2)

Polarity bridge B (low = current flow from output OB1 to OB2)

CSN

SDO

PHB

ERR

Error output (high = overcurrent on any bridge, or overtemperature). In this

mode, the pin is never tristated.

ENN

Standby mode (high active), high causes a low power mode of the device.

Setting this pin high also resets all error conditions.

INA,

INB

INA,

INB

Current control for bridge A, resp. bridge B. Refer to AGND. The sense

resistor trip voltage is 0.34V when the input voltage is 2.0V. Maximum input

voltage is 3.0V.

Input signals for microstep control in stand alone mode

Attention: When transferring these waves to SPI operation, please remark, that the mixed decay bits

are inverted when compared to stand alone mode.

INA

INB

90°

180°

270°

360°

PHA

(SDI)

PHB

(CSN)

MDAN

(ANN)

MDBN

(SCK)

Use dotted line to improve performance

at medium velocities

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

16

Calculation of the external components

Sense Resistor

Choose an appropriate sense resistor (R_S) to set the desired motor current. The maximum motor

current is reached, when the coil current setting is programmed to “1111”. This results in a current

sense trip voltage of 0.34V when the internal reference or a reference voltage of 2V is used.

When operating your motor in fullstep mode, the maximum motor current is as specified by the

manufacturer. When operating in sinestep mode, multiply this value by 1.41 for the maximum current

(I_max).

R_S= V_TRIP/ I_max

In a typical application:

R_S= 0.34V / I_max

R_S:

Current sense resistor of bridge A, B

V_TRIP

:

Programmed trip voltage of the current sense comparators

Desired maximum coil current

I_max

:

Examples for sense resistor settings

R_S

I_max

723mA

790mA

870mA

1030mA

1259mA

1545mA

0.47Ω

0.43Ω

0.39Ω

0.33Ω

0.27Ω

0.22Ω

High side overcurrent detection resistor R_SH

The TMC246 detects an overcurrent to ground, when the voltage between VS and VT exceeds

150mV. The high side overcurrent detection resistor should be chosen in a way that 100mV voltage

drop are not exceeded between VS and VT, when both coils draw the maximum current. In a sinestep

application, this is when sine and cosine wave have their highest sum, i.e. at 45 degrees,

corresponding to 1.41 times the maximum current setting for one coil. In a fullstep application this is

the double coil current.

In a microstep application:

R

_SH= 0.1V / (1.41 × I_max

)

In a fullstep application:

R

_SH= 0.1V / (2 × I_max)

R_SH:

High side overcurrent detection resistor

Maximum coil current

I_max

:

However, if the user desires to use higher resistance values, a voltage divider in the range of 10Ω to

100Ω can be used for VT. This might also be desired to limit the peak short to GND current, as

described in the following chapter.

Attention: A careful PCB layout is required for the sense resistor traces and for the R_SHtraces.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

17

Making the circuit short circuit proof

In practical applications, a short circuit does not describe a static condition, but can be of very different

nature. It typically involves inductive, resistive and capacitive components. Worst events are

unclamped switching events, because huge voltages can build up in inductive components and result

in a high energy spark going into the driver, which can destroy the power transistors. The same is true

when disconnecting a motor during operation: Never disconnect the motor during operation!

There is no absolute protection against random short circuit conditions, but pre-cautions can be taken

to improve robustness of the circuit:

In a short condition, the current can become very high before it is interrupted by the short detection,

due to the blanking during switching and internal delays. The high-side transistors allows up to 10A

flowing for the selected blank time. The lower the external inductivity, the faster the current climbs. If

inductive components are involved in the short, the same current will shoot through the low-side

resistor and cause a high negative voltage spike at the sense resistor. Both, the high current and the

voltage spikes are a danger for the driver.

Thus there are a two things to be done, if short circuits are expected:

1. Protect SRA/SRB inputs using a series resistance

2. Increase R_SHto limit maximum transistor current: Use same value as for sense resistors

3. Use as short as possible blank time

The second measure effectively limits short circuit current, because the upper driver transistor with its

fixed ON gate voltage of 7V forms a constant current source together with its internal resistance and

R_SH. A positive side effect is, that only one type of low ohmic resistor is required. The drawback is, that

power dissipation increases slightly. A high side short detection resistor of 0.33 Ohms limits maximum

high side transistor current to typically 4A. The schematic shows the modifications to be done.

However, the effectiveness of these measures should be tested in the given application.

VS

100nF

R_DIV

VT

100R

+VM

GND

R_SH=R_SA=R_SB

internal

INA/INB

R_DIVvalues for

Microstep:

Fullstep:

reference up to3V

27R

18R

12R

C_VM

SRA

100R

SRB

R_SA

R_SB

100R

GND

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

18

Oscillator Capacitor

The PWM oscillator frequency can be set by an external capacitor. The internal oscillator uses a 28kΩ

resistor to charge / discharge the external capacitor to a trip voltage of 2/3 Vcc respectively 1/3 Vcc. It

can be overdriven using an external CMOS level square wave signal. Do not set the frequency higher

than 100kHz and do not leave the OSC terminal open! The two bridges are chopped with a phase shift

of 180 degrees at the positive and at the negative edge of the clock signal.

1

f^OSC≈

40µs× COSC [nF]

f^OSC:

COSC:

PWM oscillator frequency

Oscillator capacitor in nF

Table of oscillator frequencies

f_OSCtyp. C_OSC

16.7kHz 1.5nF

20.8kHz 1.2nF

25.0kHz 1.0nF

30.5kHz 820pF

36.8kHz 680pF

44.6kHz 560pF

Please remark, that an unnecessary high frequency leads to high switching losses in the power

transistors and in the motor. For most applications a chopper frequency slightly above audible range is

sufficient. When audible noise occurs in an application, especially with mixed decay continuously

enabled, the chopper frequency should be two times the audible range. For most applications we

recommend a frequency of 36.8kHz.

Pullup resistors on unused inputs

The digital inputs all have integrated pull-up resistors, except for the ENN input, which is in fact an

analog input. Thus, there are no external pull-up resistors required for unused digital inputs which are

meant to be positive.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

19

Slope Control Resistor

The output-voltage slope of the full bridge outputs can be controlled to reduce noise on the power

supply and on the motor lines and thus electromagnetic emission of the circuit. It is controlled by an

external resistor at the SLP pin.

Operational range:

0kΩ ≤ R_SLP≤ 100kΩ

The SLP-pin can directly be connected to AGND for the fastest output-voltage slope (respectively

maximum output current). In most applications a minimum external resistance of 10 KΩ is

recommended to avoid unnecessary high switching spikes.

Only for non-A-types the slope on the lower transistors is fixed (corresponding to a 5KΩ to 10KΩ

slope control resistor). For applications where electromagnetic emission is very critical, it might be

necessary to add additional LC (or capacitor only) filtering on the motor connections.

For these applications emission is lower, if only slow decay operation is used.

Please remark, that there is a trade off between reduced electromagnetic emissions (slow slope) and

high efficiency because of low dynamic losses (fast slope).

The following table and graph depict typical behavior measured from 15% of output voltage to 85% of

output voltage. However, the actual values measured in an application depend on multiple parameters

and may stray in a user application.

Example for slope settings

t_SLPtyp. R_SLP

30ns

60ns

110ns

245ns

460ns

2.2KΩ

10KΩ

22KΩ

51KΩ

100KΩ

500

200

100

50

20

10

0

1

2

5

10

20

50

100

R_SLPin KOhm

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

20

Absolute Maximum Ratings

The maximum ratings may not be exceeded under any circumstances.

Symbol Parameter

Min

Max

36

Unit

V

V_S

Supply voltage (A-type)

Supply voltage (non-A-type)

30

V

V_MD

Supply and bridge voltage max. 20000s

(non-A-type: device disabled)

40

V

V_TR

Power transistor voltage V_OA-V_BRA, V_OB-

V_BRB,V_SA-V_OA, V_SB-V_OB(A-type)

40

30

V

Power transistor voltage V_OA-V_BRA, V_OB-

V_BRB,V_SA-V_OA, V_SB-V_OB(non-A-type)

V_CC

I_OP

Logic supply voltage

-0.5

6.0

+/-7

V

A

Output peak current (10µs pulse)

I_OC

Output current

(continuous, one bridge)

1500

1000

800

mA

T_A≤ 85°C

T_A≤ 105°C

T_A≤ 125°C

V_I

V_IA

I_IO

Logic input voltage

Analog input voltage

-0.3

V_CC+0.3V

+/-10

V

Maximum current to / from digital pins

and analog inputs

mA

V_VT

T_J

Short-to-ground detector input voltage

Junction temperature

V_S-1V V_S+0.3V

V

-40

-55

150 (1)

150

°C

T_STG

Storage temperature

(1) Internally limited

Electrical Characteristics

Operational Range

Symbol Parameter

Min Max Unit

T_AI

T_AA

T_J

Ambient temperature industrial (1)

Ambient temperature automotive

Junction temperature

-25 125

-40 125

-40 140

°C

V

V_S

Bridge supply voltage (A-type)

Bridge supply voltage (non-A-type)

7

34

28.5

V

V_CC

f_CLK

Logic supply voltage

Chopper clock frequency

Slope control resistor

3.0

5.5

50

V

kHz

KΩ

R_SLP

0

110

(1) The circuit can be operated up to 140°C, but output power derates.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

21

DC Characteristics

DC characteristics contain the spread of values guaranteed within the specified supply voltage and

temperature range unless otherwise specified. Typical characteristics represent the average value of

all parts.

Logic supply voltage:

V

_CC= 3.0 V ... 5.5 V,

Junction temperature: T_J= -40°C … 150°C,

Bridge supply voltage : V_S= 7 V … 34 V

(unless otherwise specified)

Symbol Parameter

Conditions

Min

Typ

Max

Unit

R_OUT,SinkR_DSONof sink-transistor

T_J= 25°C

V_S≥ 8V

0.12

0.19

Ω

R_OUT,SourceR_DSONof source-transistor

R_OUT,SinkR_DSONof sink-transistor max.

T_J= 25°C

V_S≥ 8V

0.22

0.20

0.37

0.84

0.36

0.26

0.47

1.12

Ω

V

T_J=150°C

V_S≥ 8V

R_OUT,SourceR_DSONof source-transistor max. T_J=150°C

V_S≥ 8V

V_DIO

Diode forward voltages of O_xx

MOSFET diodes

T_J= 25°C

I_OXX= 1.05A

V_CCUV

V_CCOK

I_CC

VCC undervoltage

2.5

2.7

2.9

0.85

0.45

37

2.9

3.0

V

VCC voltage o.k.

VCC supply current

VCC supply current standby

VCC supply current shutdown

VS undervoltage

f_osc= 25 kHz

ENN = 1

1.35

0.75

70

mA

µA

V

I_CCSTB

I_CCSD

V_SUV

V_CCOK

I_SSM

5.5

6.1

5.9

6.4

6

6.2

VS voltage o.k.

6.7

V

VS supply current with fastest

slope setting (static state)

V_S= 14V,

mA

R

_SLP= 0K

I_SSD

V_IH

VS supply current shutdown or

standby

V_S= 14V

28

50

µA

V

High input voltage

(SDI, SCK, CSN, BL1, BL2, SPE, ANN)

2.2

-0.3

100

VCC +

0.3 V

V_IL

Low input voltage

(SDI, SCK, CSN, BL1, BL2, SPE, ANN)

0.7

500

VCC

0.4

V

V_IHYS

V_OH

V_OL

-I_ISL

Input voltage hysteresis

(SDI, SCK, CSN, BL1, BL2, SPE, ANN)

300

mV

V

High output voltage

(output SDO)

-I_OH= 1mA

I_OL= 1mA

V_I= 0

VCC –

0.6

VCC –

0.2

Low output voltage

(output SDO)

0

0.1

V

Low input current

(SDI, SCK, CSN, BL1, BL2, SPE, ANN) V_CC= 3.3V

2

70

µA

10

25

V_CC= 5.0V

V_ENNH

V_EHYS

High input voltage threshold

(input ENN)

1/2 VCC

Input voltage hysteresis

0.1

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

(input ENN)

22

V_ENNH

V_OSCH

V_OSCL

V_VTD

High input voltage threshold

(input OSC)

tbd

2/3 VCC

tbd

V

Low input voltage threshold

(input OSC)

1/3 VCC

-155

350

V

VT threshold voltage

(referenced to VS)

-130

315

570

-10

-180

385

660

10

mV

kΩ

V_TRIP

V_SRS

SRA / SRB voltage at

DAC=”1111”

internal ref. or

2V at INA / INB

SRA / SRB overcurrent detection

threshold

615

V_SROFFSSRA / SRB comparator offset

voltage

0

R_INAB

INA / INB input resistance

175

264

300

Vin ≤ 3 V

AC Characteristics

AC characteristics contain the spread of values guaranteed within the specified supply voltage and

temperature range unless otherwise specified. Typical characteristics represent the average value of

all parts.

Logic supply voltage: V_CC= 5.0V,

Ambient temperature: T_A= 27°C

Bridge supply voltage: V_S= 14.0V,

Symbol Parameter

Conditions

Min

Typ

Max

Unit

f_OSC

Oscillator frequency

C_OSC= 1nF

20

25

31

kHz

±1%

using internal oscillator

t_RS, t_FSRise and fall time of outputs Oxx V_o15% to 85%

with R_SLP=0

25

ns

I_OXX= 800mA

t_RS, t_FSRise and fall time of outputs Oxx V_o15% to 85%

125

250

with R_SLP= 25KΩ

I_OXX= 800mA

t_RS, t_FSRise and fall time of outputs Oxx V_o15% to 85%

with R_SLP= 50KΩ

I_OXX= 800mA

T_BL

Effective Blank time

BL1, BL2 = V_CC

1.35

1.5

0.7

1.65

µs

T_ONMINMinimum PWM on-time

BL1, BL2 =

GND

Thermal Protection

Symbol Parameter

Conditions

Min

Typ

155

15

Max

Unit

°C

T_JOT

Thermal shutdown

145

165

T_JOTHYST_JOThysteresis

°C

T_JWT

Prewarning temperature

135

145

15

155

°C

T_JWTHYST_JWThysteresis

°C

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

23

Thermal Characteristics

Symbol Parameter

Conditions

Typ

Unit

R_THA12Thermal resistance bridge transistor junction to

ambient, one bridge chopping, fixed polarity

soldered to 2 layer

PCB

88

°K/W

R_THA22Thermal resistance bridge transistor junction to

ambient, two bridges chopping, fixed polarity

soldered to 2 layer

PCB

68

84

51

°K/W

R_THA14Thermal resistance bridge transistor junction to

ambient, one bridge chopping, fixed polarity

soldered to 4 layer

PCB (pessimistic)

R_THA24Thermal resistance bridge transistor junction to

ambient, two bridges chopping, fixed polarity

soldered to 4 layer

PCB (pessimistic)

Typical Power Dissipation at high load / high temperature

Coil:

Chopping with:

L_W= 10mH, R_W= 5.0Ω

t_DUTY= 33% ON, only slow decay

Current

Ambient

temperature voltage

Motor supply Slope

Chopper

frequency

Typ total power

dissipation

both brid- one bridge

t_SLP

ges on

560 mA

-

on

T_A

V_M

f_CHOP

P_D

-

105 °C

125 °C

70 °C

16 V

14 V

28 V

400 ns 25 KHz

490 mW

450 mW

350 mW

340 mW

1000 mW

1100 mW

800 mA

560 mA

60ns

20 KHz

25 KHz

800 mA

-

1000 mA

-

1500 mA

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

24

SPI Interface Timing

t_ES

ENN

CSN

t₁

t_CL

t_CH

t₁

SCK

SDI

t_DU

t_DH

bit11

t_D

bit10

bit0

t_ZC

SDO

bit11

bit10

Propagation Times

(3.0 V ≤ VCC ≤ 5.5 V, -40°C ≤ Tj ≤ 150°C; V_IH= 2.8V, V_IL= 0.5V; tr, tf = 10ns; C_L= 50pF,

unless otherwise specified)

Symbol

f_SCK

Parameter

Conditions

Min

DC

50

Typ

Max

Unit

MHz

ns

SCK frequency

ENN = 0

4

t₁

SCK stable before and after CSN

change

t_CH

t_CL

t_DU

t_DH

t_D

Width of SCK high pulse

Width of SCK low pulse

SDI setup time

100

40

ns

µs

SDI hold time

50

SDO delay time

C_L= 50pF

*)

40

100

t_ZC

t_ES

t_PD

CSN high to SDO high impedance

ENN to SCK setup time

50

30

CSN high to OA / OB output

polarity change delay

**)

3

5

t_OSC+ 4

7

t_LD

Load indicator valid after OA / OB

output polarity change

µs

*) SDO is tristated whenever ENN is inactive (high) or CSN is inactive (high).

**) Whenever the PHA / PHB polarity is changed, the chopper is restarted for that phase. However, the chopper does not switch

on, when the SRA resp. SRB comparator threshold is exceeded upon the start of a chopper period.

Using the SPI interface

The SPI interface allows either cascading of multiple devices, giving a longer shift register, or working

with a separate chip select signal for each device, paralleling all other lines. Even when there is only

one device attached to a CPU, the CPU can communicate with it using a 16 bit transmission. In this

case, the upper 4 bits are dummy bits.

SPI Filter

To prevent spikes from changing the SPI settings, SPI data words are only accepted, if their length is

at least 12 bit.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

25

ESD Protection

Please be aware, that the TMC246 is an ESD sensitive device due to integrated high performance

MOS transistors.

ESD sensitive device

If the ICs are manually handled before / during soldering, special precautions have to be taken to

avoid ESD voltages above 100V HBM (Human body model). For automated SMD equipment the

internal device protection is specified with 1000V CDM (charged device model), tbf.

When soldered to the application board, all inputs and outputs withstand at least 1000V HBM.

TMC246 / TMC246A DATA SHEET (V2.03 / Nov. 6th, 2006)

26

Application Note: Extending the Microstep Resolution

For some applications it might be desired to have a higher microstep resolution, while keeping the

advantages of control via the serial interface. The following schematic shows a solution, which adds

two LSBs by selectively pulling up the SRA / SRB pin by a small voltage difference. Please remark,

that the lower two bits are inverted in the depicted circuit. A full scale sense voltage of 340mV is

assumed. The circuit still takes advantage of completely switching off of the coils when the internal

DAC bits are set to “0000”. This results in the following comparator trip voltages:

Current setting Trip voltage

(MSB first)

0000xx

000111

000110

000101

000100

...

0 V

5.8 mV

11.5 mV

17.3 mV

23 mV

111101

111100

334.2 mV

340 mV

SPI bit

DAC bit

SPI bit

15

/B1

7

14

/B0

6

13

/A1

5

12

/A0

4

11

MDA

3

10

A5

2

9

A4

1

8

A3

0

DAC bit

A2

PHA MDB

B5

B4

B3

B2

PHB

SCK

SDI

SCK

SDI

TMC236 /

TMC239

SDO

CSN

SRA

110R

4.7nF

opt.

47K

R_S

/CS

47K

+V_CC

100K

/OE

C2

/MR

C1

/DACA.0

DS1D

Q0

Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q7'

/DACA.1

/DACB.0

/DACB.1

Free for

second

TMC239

74HC595

Vcc = 5V

C

Note: Use a 74HC4094

SDO

Q

D

instead of the HC595 to get

rid of the HC74 and inverter

1/2 74HC74

Please see the FAQ document for more application information.

ⁱSPI is a trademark of Motorola

型号	制造商	描述	价格	文档
TMC246_1	TRINAMIC	High current microstep stepper motor driver with stallGuard™, protection / diagnostics and SPI Interface	获取价格
TMC248	TRINAMIC	Low-cost stepper driver	获取价格
TMC248-LA	TRINAMIC	Low-cost stepper driver	获取价格
TMC249	TRINAMIC	Microstep Driver for External MOSFETs for up to 4A with stall Guard™	获取价格
TMC249-A	ETC	High Current Microstep Stepper Motor Driver with Sensorless Stall D e t e c t i o n ,P rotection / Diagnosis and SPI Interface	获取价格
TMC249-EVAL	ETC	High Current Microstep Stepper Motor Driver with Sensorless Stall D e t e c t i o n ,P rotection / Diagnosis and SPI Interface	获取价格
TMC249-HVHR	TRINAMIC	Evaluation Board for TMC249 with High Voltage and High Resolution	获取价格
TMC249-SA	ETC	High Current Microstep Stepper Motor Driver with sensorless stall detection, protection / diagnostics and SPI Interface	获取价格
TMC2490A	FAIRCHILD	Multistandard Digital Video Encoder	获取价格
TMC2490A	CADEKA	Multistandard Digital Video Encoder	获取价格

TMC246_06

TMC246_06 概述

TMC246_06 数据手册

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