UC3178 [TI]
Full Bridge Power Amplifier; 全桥功率放大器型号: | UC3178 |
厂家: | TEXAS INSTRUMENTS |
描述: | Full Bridge Power Amplifier |
文件: | 总6页 (文件大小:307K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
UC3178
Full Bridge Power Amplifier
FEATURES
DESCRIPTION
•
•
•
Precision Current Control
The UC3178 full-bridge power amplifier, rated for continuous output current
of 0.45 Amperes, is intended for use in demanding servo applications. This
device includes a precision current sense amplifier that senses load current
with a single resistor in series with the load. The UC3178 is optimized to con-
sume a minimum of supply current, and is designed to operate in both 5V
and 12V systems. The power output stages have a low saturation voltage
and are protected with current limiting and thermal shutdown. When inhibited,
the device will draw less than 1.5mA of total supply current.
±
450mA Load Current
1.2V Typical Total Vsat at
450mA
•
•
•
Programmable Over-Current
Control
Range Control for 4:1 Gain
Change
Auxiliary functions on this device include a load current sensing and rectifica-
tion function that can be configured with the device’s over-current comparator
to provide tight control on the maximum commanded load current. The closed
loop transconductance of the configured power amplifier can be switched be-
tween a high and low range with a single logic input. The 4:1 change in gain
can be used to extend the dynamic range of the servo loop. Bandwidth vari-
ations that would otherwise result with the gain change can be controlled with
a compensation adjust pin.
Compensation Adjust Pin for
Range Bandwidth Control
•
•
•
Inhibit Input and UVLO
3V to 15V Operation
12mA Quiescent Supply
Current
This device is packaged a power PLCC, "QP" package which maintains a
standard 28-pin outline, but with 7 pins along one edge directly tied to the die
substrate for improved thermal performance.
BLOCK DIAGRAM
UDG-92010
5/93
UC3178
ABSOLUTE MAXIMUM RATINGS
CONNECTION DIAGRAM
Input Supply Voltage, (VIN(+), VC(+)). . . . . . . . . . . . . . . . . . 20V
O/C Sense, Logic Inputs, and REF Input
PACKAGE PIN FUNCTION
PLCC - 28 (Top View)
QP Package
FUNCTION
PIN
Maximum forced voltage . . . . . . . . . . . . . . . . . -0.3V to 10V
Inhibit
1
2
3
4
±
Maximum forced current . . . . . . . . . . . . . . . . . . . . . . 10mA
O/C Force
O/C Sense
Range
A & B Amplifier Inputs . . . . . . . . . . . . . -0.3V to (VIN(+) + 1.0V)
O/C Indicate Open Collector Output Voltage . . . . . . . . . . . . 20V
A and B Output Currents(continuous)
C/S(+)
5
Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.6A
Output Diode Current (pulsed)* . . . . . . . . . . . . . . . . . . . . . 0.5A
O/C Ind Output Current(continuous) . . . . . . . . . . . . . . . . 20mA
Operating Junction Temperature . . . . . . . . . . . . . . . . . . +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Comp Adj
O/C Ind
AIN(+)
6
7
8
9
AIN(-)
VC(+) Supply
A Output
Pwr Gnd
Pwr Gnd
Pwr Gnd
Pwr Gnd
Pwr Gnd
Pwr Gnd
Pwr Gnd
B Output
VIN(+)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
*Notes: Unless otherwise indicated, voltages are referenced to
ground and currents are positive into, negative out of, the speci-
fied terminals, "Pulsed" is defined as a less than 10% duty cy-
cle pulse with a maximum duration of 500µs.
THERMAL DATA
QP package: (see packaging section of UICC data book for more
details on thermal performance)
BIN(-)
BIN(+)
Thermal Resistance Junction to Leads, θjl . . . . . . . . 15°C/W
Thermal Resistance Junction to Ambient, θja . . . 30-40°C/W
REF Input
C/S(+)
C/S Out
IDIF Out
IDIF REF
Ground
Note: The above numbers for θjl are maximums for the limiting
thermal resistance of the package in a standard mounting con-
figuration. The θja numbers are meant to be guidelines for the
thermal performance of the device/pc-board system. All of the
above numbers assume no ambient airflow.
Unless otherwise stated specifications hold for TA = 0°C to 70°C, VC(+) = VIN(+) =
12V, REF Input = VIN(+)/2, O/C Input & Inhibit Input = 0V.
ELECTRICAL CHARACTERISTICS:
PARAMETER
Input Supply
TEST CONDITIONS
MIN
TYP
MAX UNITS
VIN (+)Supply Current
12
1.2
12
16
2.0
16
mA
mA
mA
mA
V
VC(+) Supply Current
Total Supply Current
IOUT = OA
Supplies = 5V,IOUT = OA
Supplies = 12V,IOUT = OA
low to high
13
18
VIN(+) UVLO Threshold
UVLO Threshold Hysterisis
Over-Current (O/C) Comparator
Input Bias Current
2.6
300
2.8
mV
V input = 0.8V
low to high
-1.0
0.97
85
-.01
1.0
µA
V
Thresholds
1.03
115
0.45
5.0
Threshold Hysterisis
O/C IND Vsat
100
0.2
mV
V
IOUT = 5mA, V input low
VOUT = 20V
O/C IND Leakage
µA
Power Amplifiers A and B
Input Offset Voltage
A Amplifier, VCM = 6V
4.0
mV
mV
µΑ
dB
B Amplifier, VCM = 6V
12.0
Input Bias Current
CMRR
VCM = 6V
-500
70
-50
90
VCM = 0.5 to 13V, Supplies = 15V
VIN(+) = 4 to 15V, VCM = 1.5V
Supplies = 12V, VOUT = 1V, IOUT = 300mA
to VOUT = 10.5V, IOUT = -300mA
PSRR
70
90
dB
Large Signal Voltage Gain
3.0
15.0
V/mV
2
UC3178
Unless otherwise stated specifications hold for TA = 0°C to 70°C , VC(+) = VIN(+) = 12V,
REF Input = VIN(+)/2, O/C Input & Inhibit Input = 0V.
ELECTRICAL
CHARACTERISTICS (cont.):
PARAMETER
Power Amplifiers A & B (cont.)
Gain Bandwith Product
TEST CONDITIONS
MIN
TYP
MAX UNITS
A Amplifier
B Amplifier
2.0
1.0
MHz
MHz
V/µs
A
Slew Rate
1.0
High-Side Current Limit
Output Saturation Voltage
0.45
0.65
0.75
0.85
0.9
High-Side, IOUT = -100mA
High-Side, IOUT = -300mA
High-Side, IOUT = -450mA
Low-Side, IOUT = 100mA
Low-Side, IOUT = 300mA
Low-Side, IOUT = 450mA
Total Vsat, IOUT = 100mA
Total Vsat, IOUT = 300mA
Total Vsat, IOUT = 450mA
ID = 450mA
V
V
V
0.2
V
0.25
0.30
0.95
1.05
1.25
1.30
V
V
1.2
1.4
1.6
V
V
V
V
High-Side Diode, Vf
Current Sense Amplifier
Input Offset Voltage
VCM = 6V, Low range mode
2.0
4.0
mV
mV
High range mode
Input Offset Change
with Common Mode Input
Voltage Gain
VCM = -1V to 13V, Supplies = 12V, Low Range Mode
VCM = -1V to 13V, Supplies = 12V, High Range Mode
VDIFF = +1.0 to -1.0V, Vcm = 6V, High Range Mode
VDIFF = +1.0 to -1.0V, Vcm = 6V, Low Range Mode
Low-Side, IOUT = 1mA
2000 µV/V
4000 µV/V
0.485 0.50 0.515
V/V
V/V
V
1.95
2.0
0.1
0.1
21
2.05
0.3
0.3
27
Saturation Voltage
High-Side, IOUT = -1mA, Referenced to = VIN(+)
(REF Input - C/S(+))/48kohms, Tj = 25°C
V
Input Bias Current at Ref. Input
15
µA/V
Load Current Sense and Rectification
Sense Buffer Offset Voltage
Sense Buffer CMRR
±
REF Input to IDIF REF, IOUT = 1mA
10
mV
dB
±1mA, REF Input = 2V to 10V
IOUT =
70
90
± 100
µA, IDIF Out = 1V
IDIF REF to IDIF Out Current
Ratio
IDIF =
0.95
0.94
1.0
1.0
1.0
1.05
1.06
5.0
A/A
A/A
µA/V
±1mA, IDIF Out = 1V
IDIF =
± 1mA, VIN
(+)
= 4V to 15V,REF Input = 2V
IDIF Out Supply Sensitivity
IDIF Out Common Mode Sensitivity
(delta IDIF Out/delta REF Input)
Auxiliary Functions
IDIF Out =
±1mA, REF Input = 2V to10V, IDIF Out = 1V
IOUT =
1.0
5.0
1.7
µA/V
Inhibit Input Threshold
Inhibit Input Current
0.6
-1.0
0.6
1.1
-0.5
1.1
50
V
µA
V
Inhibit Input = 1.7V
O/C Force Input Threshold
O/C Force Input Current
Range Input Threshold
Range Input Current
1.7
100
1.7
O/C Force Input = 1.7V
µA
V
0.6
1.1
50
Range Input = 1.7V
Range Input = 0V, Pin Current =
to AOUT
100
µA
±500µA, Referenced
COMP ADJ Pin Saturation
Voltage
0.02
0.1
V
COMP ADJ Leakage Current
Range Input = 1.7V, Supplies = 12V
AOUT
-VComp Adj = ±6V
5.0
1.5
µA
mA
°C
Total Supply Current When Inhibited VIN(+) and VC(+) currents
Thermal Shutdown Temperature
1.0
165
3
UC3178
PIN DESCRIPTIONS:
A & B OUT: Outputs for the A & B power amplifiers, IDIF REF: Output of the IDIF sense buffer. Voltage on this
providing differential drive to the load during normal op- pin will track the applied voltage on the REF Input pin.
eration. During a UVLO, Inhibit, or O/C condition both of Current through this pin is full wave rectified and appears
these outputs will be in a high, source only state. High- as a current sourced from the IDIF OUT pin.
side diodes are included to catch inductive load currents
flowing into these pins, inductive kicks on the low-side are
caught by the high-side output transistors.
Inhibit : A high impedance logic input that disables the A
and B power amplifiers, the IDIF sense buffer, and the
Current Sense amplifier. This input has an internal pull-up
AIN(+): Non-inverting input to the A amplifier. Normally tied that will inhibit the device if the input is left open.
to the REF Input when the current sense amplifier is used.
O/C Force: Logic input that forces the O/C condition.
AIN(-): Inverting input to the A amplifier. Used as the sum-
O/C IND: Open collector ouput that indicates, with an ac-
ming node to close the loop on the overall power
tive low state, an O/C condition.
amplifier.
O/C Sense: Input to the Over Current Comparator. When
this input is above its 1V threshold the low-side devices of
both the A & B power amplifiers will be disabled forcing a
high, source only, state at both outputs.
BIN(+): Non-inverting input to the B amplifier. This pin nor-
mally sets the reference point for the differential voltage
swing at the load.
BIN(-): Inverting input to the B amplifier. Used to program
the gain of the B amplifier.
PWR GND: Current return for all high level circuitry, this
pin should be connected to the same potential as GND.
COMP ADJ: The compensation adjust pin allows the user
Range: When this pin is open or at a logic low potential,
to provide an auxiliary compensation network for the A am-
the current sense amplifier will be in its low range mode.
plifier that is only active when the current sense amplifier is
In this mode the voltage gain of the amplifier will be 2. If
in the low range. With this option, the user can control the
this pin is brought to a logic high, the gain of the current
change in bandwidth that would otherwise result from the
sense amplifier will change into its high range value of
0.5. This factor of four change in gain will vary the overall
gain change in the feedback loop.
C/S(+): The non-inverting input to the current sense ampli- transconductance of the power amplifier by the same ra-
fier is typically tied to the load side of the series current tio, with the transconductance being the highest in the
sense resistor. This pin can be pulled below ground during high mode. This feature allows improved dynamic range
an abrupt load current change with an inductive load. of load current control for a given control input range and
Proper operation of the current sense amplifier will result if resolution.
this pin does not go below ground by an amount greater
than:
REF Input: Sets the Reference level at the C/S Output,
and is normally tied to the system reference level for in-
puts to the power amplifier.
(REF Input / 2 ) - 0.3V.
C/S(-): The inverting input to the current sense amplifier is
VIN(+): Provides bias supply to the device. The High-Side
typically tied to the connection between the B amplifier
drive to the power stages on both the A and B amplifiers
output and the current sense resistor that is in series with
is referenced to this pin. The High-side saturation volt-
ages, and UVLO are specified and measured with respect
the load.
C/S Output: The output of the current sense amplifier has to this supply pin.
a 1.5mA current source pull-up and an active NPN pull-
down. The output will pull to within 0.3V of either rail with
a load current of less than 1mA.
VC(+): This supply pin is the high current supply to the
collectors of the high-side NPN output devices on the A
and B amplifiers. This supply should be powered when-
GND: Reference point for the internal reference, O/C ever the A or B amplifiers are to be activated. This pin can
comparator, and other low-level circuitry.
operate approximately 400mV below the VIN(+) supply
without affecting the voltage available to the load.
IDIF OUT: Current source output pin. The value of the out-
put current is nominally equal to the magnitude of the
current through the IDIF REF pin.
4
UC3178
TYPICAL APPLICATION
UDG-92009
Power amplifier transconductance
where:
Il is the load current
Il RB
Vs RA
1
Go =
=
•
Vs is the input command voltage
AVCS is the current sense amplifier gain
= 2.0 in low range mode
= 0.5 in high range mode
VO/C is the 1.0V over-current comparator threshold
AV • RS
CS
Peak commanded load current
RD
IlMAX = Vo/c
•
RS • AVCS • RE
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5
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