TLC5924 [TI]
16-CHANNEL LED DRIVER WITH DOT CORRECTION AND PRE-CHARGE FET; 16通道LED驱动器,具有点校正和预充电FET型号: | TLC5924 |
厂家: | TEXAS INSTRUMENTS |
描述: | 16-CHANNEL LED DRIVER WITH DOT CORRECTION AND PRE-CHARGE FET |
文件: | 总23页 (文件大小:743K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
TLC5924
DAP
RHB
www.ti.com
SLVS626–JUNE 2006
16-CHANNEL LED DRIVER WITH DOT CORRECTION AND PRE-CHARGE FET
FEATURES
APPLICATIONS
•
•
•
•
Monocolor, Multicolor, Fullcolor LED Display
Monocolor, Multicolor LED Signboard
Display Backlighting
•
16 Channels
•
Drive Capability
– 0 to 80 mA (Constant-Current Sink)
Constant Current Accuracy: ±1% (typical)
Serial Data Interface
Multicolor LED lighting applications
•
•
•
•
•
•
•
•
•
DESCRIPTION
Fast Switching Output: Tr / Tf = 10ns (typical)
CMOS Level Input/Output
The TLC5924 is a 16 channel constant-current sink
driver. Each channel has a On/Off state and a
128-step adjustable constant current sink (dot
correction). The dot correction adjusts the brightness
variations between LED, LED channels and other
LED drivers. Both dot correction and On/Off state are
accessible via a serial data interface. A single
external resistor sets the maximum current of all 16
channels.
30 MHz Data Transfer Rate
VCC = 3.0 V to 5.5 V
Operating Temperature = –40°C to 85°C
LED Supply Voltage up to 17 V
32-pin HTSSOP(PowerPAD™) and QFN
Packages
•
Dot Correction
Each constant-current output has a pre-charge FET
that enables an improvement in image quality of the
dynamic-drive LED display.
– 7 bit (128 Steps)
– individual adjustable for each channel
Controlled In-Rush Current
Pre-Charge FET
The TLC5924 features two error information circuits.
The LED open detection (LOD) indicates a broken or
disconnected LED at an output terminal. The thermal
error flag (TEF) indicates an over-temperature
condition.
•
•
•
Error Information
– LOD: LED Open Detection
– TEF: Thermal Error Flag
FUNCTIONAL BLOCK DIAGRAM
VCC GND PGND SCLK
SIN
VUP
BLANK
MODE
XLAT
VUP
MODE
Constant Current
Driver
0
0
LOD
0
1
1
0
OUT0
Delay
x0
On/Off Register
0
Max. OUTn
Current
IREF
0
7−bit DC Register
6
On/Off
BLANK
VUP
Input
Shift
Register
1
16
16
Constant Current
Driver
LOD
OUT1
Delay
x1
1
On/Off Register
112
15
0
7
7−bit DC Register
13
LED Open
Detection
(LOD)
DC Input
Shift
Register
BLANK
VUP
Temperature
Error Flag
(TEF)
BLANK
Constant Current
Driver
15
1
0
LOD
OUT15
Delay
x15
15
111
On/Off Register
XERR
105
7−bit DC Register
111
0
1
MODE
SOUT
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Copyright © 2006, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
TLC5924
www.ti.com
SLVS626–JUNE 2006
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION(1)
TA
Package
Part Number(1)
TLC5924DAP
TLC5924RHB
32-pin, HTSSOP, PowerPAD™
32-pin, 5 mm x 5 mm QFN
–40°C to 85°C
(1) For the most current package and ordering information, see the Package Option Addendum at the end
of this document, or see the TI website at www.ti.com.
(1)(2)
ABSOLUTE MAXIMUM RATINGS
TLC5924
–0.3 to 6
–0.3 to 16
90
UNIT
VCC Supply voltage(2)
VUP Pre-charge voltage
V
V
mA
V
IO
VI
Output current (dc)
Input voltage range(2)
I(OUT0) to I(OUT15)
V(BLANK), V(XLAT), V(SCLK), V(SIN), V(MODE), V(IREF)
V(SOUT), V(XERR)
–0.3 to VCC + 0.3
–0.3 to VCC + 0.3
-0.3 to VUP
2
V
VO
Output voltage range(2)
V(OUT0) to V(OUT15)
V
HBM (JEDEC JESD22-A114, Human Body Model)
CDM (JEDEC JESD22-C101, Charged Device Model)
kV
ESD rating
500
V
Tstg
Storage temperature range
–40 to 150
42.54
°C
HTSSOP (DAP)
QFN (RHB)
mW/°C
mW/°C
Power dissipation rating at (or
above) TA = 25°C(3)
27.86
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltage values are with respect to network ground terminal.
(3) See SLMA002 for more information about PowerPAD™
RECOMMENDED OPERATING CONDITIONS—DC Characteristics
MIN
3
NOM
MAX
5.5
UNIT
V
VCC Supply voltage
VUP Pre-charge voltage
3
15
V
VO
VIH
VIL
IOH
IOL
Voltage applied to output, (Out0 - Out15)
VUP
VCC
0.2 VCC
–1
V
High-level input voltage
Low-level input voltage
High-level output current
Low-level output current
0.8 VCC
GND
V
V
VCC = 5 V at SOUT
VCC = 5 V at SOUT, XERR
OUT0 to OUT15
mA
mA
mA
°C
1
IOLC Constant output current
TA
80
Operating free-air temperature range
-40
85
2
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SLVS626–JUNE 2006
RECOMMENDED OPERATING CONDITIONS—AC Characteristics
VCC = 3 V to 5.5 V, TA = -40°C to 85°C (unless otherwise noted)
MIN TYP
MAX
UNIT
MHz
ns
fSCLK
Clock frequency
SCLK
30
twh0, twl0 CLK pulse duration
SCLK=H/L
16
20
10
10
10
10
10
10
10
10
10
10
twh1
tsu0
tsu1
tsu1a
tsu2
tsu3
th0
XLAT pulse duration
Setup time
XLAT=H
SIN to SCLK↑ (1)
ns
SLCK↑ to XLAT↓(dot correction data)
SCLK↑to XLAT↑ (ON/OFF data)
MODE↑↓ to SCLK↑
MODE↑↓ to XLAT↑
SCLK↑ to SIN
ns
ns
th1
XLAT↓ to SCLK↑ (dot correction data)
XLAT↑ to SCLK↑ (ON/OFF data)
SCLK↑to MODE↑↓
th1a
th2
Hold time
th3
XLAT↓ to MODE↑↓
(1) "↑" and "↓" indicates a rising edge, and a falling edge respectively.
ELECTRICAL CHARACTERISTICS
VCC = 3 V to 5.5 V, TA = –40°C to 85°C (unless otherwise noted)
PARAMETER
High-level output voltage
Low-level output voltage
Input current
TEST CONDITIONS
MIN TYP
MAX UNIT
VOH
VOL
II
IOH = –1 mA, SOUT
VCC– 0.5
V
IOL = 1 mA, SOUT
0.5
1
V
VI = VCC or GND, BLANK, XLAT, SCLK, SIN, MODE
–1
µA
No data transfer, All output OFF, VO = 1 V, R(IREF) = 10
kΩ
6
15
32
No data transfer, All output OFF, VO = 1 V, R(IREF) = 1.3
kΩ
ICC
Supply current
mA
Data transfer 30 MHz, All output ON, VO = 1 V,
R(IREF) = 1.3 kΩ
Data transfer 30 MHz, All output ON, VO = 1 V,
R(IREF) = 600 Ω
36
80
65(1)
90
IOLC
ILO0
ILO1
Constant sink current
Leakage output current
All output ON, VO = 1 V, R(IREF) = 600 Ω
70
mA
µA
µA
All output OFF, VO = 15 V, R(IREF) = 600 Ω, OUT0 to
OUT15
0.1
VXERR = 5.5 V, No TEF and LOD
10
∆IOLC0 Constant sink current error
All output ON, VO = 1 V, R(IREF) = 600 Ω, OUT0 to OUT15
±1%
±4%
± 4%
device to device, averaged current from OUT0 to OUT15,
R(IREF) = 600 Ω
∆IOLC1 Constant sink current error
±8.5%
±4
All output ON, VO = 1 V, R(IREF) = 600 Ω,
OUT0 to OUT15, VCC = 3 V to 5.5 V
∆IOLC2 Line regulation
∆IOLC3 Load regulation
±1
±2
%/V
%/V
All output ON, VO = 1 V to 3 V, R(IREF) = 600 Ω,
OUT0 to OUT15
±6
R(ON) Pre-charge FET on-resistance VUP = 3 V, VO = 0 V, OUT0 to OUT15
10
180
0.4
KΩ
°C
V
T(TEF) Thermal error flag threshold
V(LOD) LED open detection threshold
V(IREF) Reference voltage output
Junction temperature, rising temperature(2)
150
160
0.3
R(IREF) = 600 Ω
1.20 1.24
1.28
V
(1) Measured at device start-up temperature. Once the IC is operating (self heating), lower ICC values will be seen. See Figure 20.
(2) Not tested. Specified by design.
3
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SLVS626–JUNE 2006
DISSIPATION RATINGS
POWER RATING
DERATING FACTOR
ABOVE TA = 25°C
POWER RATING
POWER RATING
PACKAGE
TA < 25°C
TA = 70°C
TA = 85°C
32-pin HTSSOP with PowerPAD(1)
soldered
32-pin HTSSOP with PowerPAD(1)
unsoldered
5318 mW
2820 mW
3482 mW
42.54 mW/°C
22.56 mW/°C
27.86 mW/°C
3403 mW
1805 mW
2228 mW
2765 mW
1466 mW
1811 mW
32-pin QFN
(1) The PowerPAD is soldered to the PCB with a 2 oz. copper trace. See SLMA002 for further information.
SWITCHING CHARACTERISTICS
PARAMETER
TEST CONDITIONS
MIN TYP MAX UNIT
(1)
tr0
SOUT(see
)
16
ns
Rise time
(2)
tr1
OUTn, VCC = 5 V, TA = 60°C, DCx = 7F (see
)
10
10
30
16
(1)
tf0
SOUT (see
)
Fall time
ns
(2)
tf1
OUTn, VCC = 5 V, TA = 60°C, DCx = 7F (see
)
30
(3)(4)
tpd0
tpd1
tpd2
tpd3
tpd4
tpd5
td
SCLK↑ to SOUT↑↓ (see
)
30
(3)
MODE↑↓ to SOUT↑↓ (see
)
30
BLANK↑↓ to OUT0↑↓ (see (5)), Sink current On/Off
80
Propagation delay time
Output delay time
ns
ns
(5)
XLAT↑ to OUT0↑↓ (see
OUTn↑↓ to XERR↑↓ (see
)
60
(6)
)
1000
1000
30
(7)
XLAT↑ to IOUT(dot-correction) (see
)
(5)
OUTn↑ to OUT(n+1)↑, OUTn ↓ to OUT(n+1)↓ (see
)
14
22
(1) See Figure 4. Defined as from 10% to 90%
(2) See Figure 5. Defined as from 10% to 90%
(3) See Figure 4, Figure 16
(4) "↑" and "↓" indicates a rising edge, and a falling edge respectively.
(5) See Figure 5 and Figure 16
(6) See Figure 5, Figure 6, and Figure 16
(7) See Figure 5
RHB PACKAGE
(TOP VIEW)
DAP PACKAGE
(TOP VIEW)
1
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
GND
BLANK
XLAT
SCLK
SIN
VCC
2
IREF
3
MODE
XERR
SOUT
VUP
XERR 25
MODE 26
IREF 27
VCC 28
16 OUT10
15 PGND
14 OUT9
13 OUT8
12 OUT7
11 OUT6
10 PGND
4
5
6
VUP
THERMAL
PAD
7
OUT0
OUT1
PGND
OUT2
OUT3
OUT4
OUT5
PGND
OUT6
OUT7
OUT15
OUT14
PGND
OUT13
OUT12
OUT11
OUT10
PGND
OUT9
OUT8
8
GND 29
BLANK 30
XLAT 31
SCLK 32
9
(QFN)
10
11
12
13
14
15
16
9
OUT5
4
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SLVS626–JUNE 2006
Terminal Functions
TERMINAL
NO.
I/O
DESCRIPTION
NAME
TSSOP
QFN
Blank (Light OFF). When BLANK=H, All OUTn outputs are forced to VUP level. When
BLANK=L, ON/OFF of OUTn outputs are controlled by input data.
BLANK
2
30
I
GND
IREF
1
29
27
Ground
31
I/O Reference current terminal
Mode select. When MODE=L, SIN, SOUT, SCLK, XLAT are connected to ON/OFF control
logic. When MODE=H, SIN, SOUT, SCLK, XLAT are connected to dot-correction logic.
MODE
30
26
I
OUT0
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
OUT9
OUT10
OUT11
OUT12
OUT13
OUT14
OUT15
7
3
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
Constant current output
8
4
10
11
12
13
15
16
17
18
20
21
22
23
25
26
6
7
8
9
11
12
13
14
16
17
18
19
21
22
9, 14,
19, 24
5, 10,
15, 20
PGND
VUP
Power ground
6, 27
2, 23
Pre-charge power supply voltage
Data shift clock. Note that the internal connections are switched by MODE (pin #30). At
SCLK↑, the shift-registers selected by MODE shift the data.
SCLK
4
32
I
SIN
5
1
I
Data input of serial I/F
Data output of serial I/F
Power supply voltage
SOUT
VCC
28
32
24
28
O
Error output. XERR is open drain terminal. XERR transistions from H to L when LOD or TEF
detected.
XERR
29
25
O
I
Data latch signal. When MODE = L (ON/OFF data mode), XLAT is an edge-triggered latch
signal of ON/OFF registers. The serial data in ON/OFF input shift registers is latched into the
ON/OFF registers at the rising edge of XLAT. When MODE = H (DC data mode), XLAT is a
level-triggered latch signal of dot correction registers. The serial data in DC input shift
registers is written into dot correction registers when XLAT = H. The data in dot correction
registers is held constant when XLAT = L.
XLAT
3
31
5
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SLVS626–JUNE 2006
PIN EQUIVALENT INPUT AND OUTPUT SCHEMATIC DIAGRAMS
(Note: Resistor values are equivalent resistance and not tested).
VCC
400 W
INPUT
GND
Figure 1. Input Equivalent Circuit (BLANK, XLAT, SCLK, SIN, MODE)
10 W
SOUT
GND
Figure 2. Output Equivalent Circuit
20 W
XERR
GND
Figure 3. Output Equivalent Circuit (XERR)
PARAMETER MEASUREMENT INFORMATION
SOUT
15 pF
Figure 4. Test Circuit for tr0, tf0, tpd0, tpd1
VUP
51 Ω
OUTn
15 pF
Figure 5. Test Circuit for tr1, tf1, tpd2, tpd3, tpd5, ttd
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PARAMETER MEASUREMENT INFORMATION (continued)
470 kΩ
XERR
Figure 6. Test Circuit for tpd4
7
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SLVS626–JUNE 2006
PRINCIPLES OF OPERATION
Setting Maximum Channel Current
The maximum output current per channel is set by a single external resistor, R(IREF), which is placed between
IREF and GND. The voltage on IREF is set by an internal band gap V(IREF) with a typical value of 1.24V. The
maximum channel current is equivalent to the current flowing through R(IREF) multiplied by a factor of 40. The
maximum output current per channel can be calculated by Equation 1:
V
IREF
I
+
40
MAX
R
IREF
(1)
where:
VIREF = 1.24V typ.
RIREF = User selected external resistor ®IREF should not be smaller than 600 Ω)
Figure 17 shows the maximum output current, IOLC, versus R(IREF) . In Figure 17, R(IREF) is the value of the
resistor between IREF terminal to ground, and IOLC is the constant output current of OUT0,.....OUT15. A variable
power supply may be connected to the IREF pin through a resistor to change the maximum output current per
channel. The maximum output per channel is 40 times the current flowing out of the IREF pin. The maximum
current from IREF equals 1.24V/600Ω.
Setting Dot-Correction
The TLC5924 has the capability to fine adjust the current of each channel, OUT0 to OUT15 independently. This
is also called dot correction. This feature is used to adjust the brightness deviations of LED connected to the
output channels OUT0 to OUT15. Each of the 16 channels can be programmed with a 7-bit word. The channel
output can be adjusted in 128 steps from 0% to 100% of the maximum output current IMAX. Dot correction for all
channels must be entered at the same time. Equation 2 determines the output current for each OUTn:
I
DC
n
MAX
+
I
Outn
where:
127
(2)
IMax = the maximum programmable current of each output
DCn = the programmed dot-correction value for output n (DCn = 0, 1, 2 ...127)
n = 0, 1, 2 ... 15
Dot correction data are entered for all channels at the same time. The complete dot correction data format
consists of 16 x 7-bit words, which forms a 112-bit wide serial data packet. The channel data is put one after
another. All data is clocked in with MSB first. Figure 7 shows the DC data format. The DC15.6 in Figure 7 stands
for the 6th most significant bit for output 15.
MSB
111
LSB
0
105
104
7
6
DC 15.6
DC 15.0
DC 14.6
DC 1.0
DC 0.6
DC 0.0
DC OUT15
DC OUT0
DC OUT14 − DC OUT1
Figure 7. DC Data Format
To input data into dot correction register, MODE must be set to high. The internal input shift register is then set
to 112-bit width. After all serial data is clocked in, a high level pulse of XLAT signal connects the serial data to
the dot correction register. The dot correction registers are level-triggered latches of XLAT signal. The serial
data is latched into the dot correction registers when XLAT goes low. The data in dot correction registers is held
constant when XLAT is low. BLANK signal does not need to be high to latch in new data. Since XLAT is a
level-triggered signal when MODE is high, SCLK and SIN must not be changed while XLAT is high. (Figure 16).
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PRINCIPLES OF OPERATION (continued)
Output Enable
When BLANK = H, TLC5924 switches off the sink current of all OUTn with each output delay, then switches on
the pre-charge FET of all OUTn. When BLANK = L, the TLC5924 switches off the pre-charge FETs, and enables
the sink current set by input data. See "Delay Between Outputs" section for more detail on the output delay.
Table 1. BLANK Signal Truth Table
BLANK
LOW
OUT0 - OUT15
Normal condition
VUP
HIGH
Setting Channel On/Off Status
All OUTn channels of TLC5924 can be switched on or off independently. Each of the channels can be
programmed with a 1-bit word. On/Off data are entered for all channels at the same time. The complete On/Off
data format consists of 16 x 1-bit words, which form a 16-bit wide data packet. The channel data is put one after
another. All data is clocked in with MSB first. Figure 8 shows the On/Off data format.
MSB
15
LSB
0
On/Off On/Off On/Off
OUT15 OUT14 OUT13
On/Off On/Off On/Off
OUT0
OUT2
OUT1
On/Off Data
Figure 8. On/Off Data Format
To input On/Off data into On/Off register MODE must be set to low. The internal input shift register is then set to
16 bit width. After all serial data is clocked in, a rising edge of XLAT is used to latch data into the On/Off
register. The ON/OFF register is an edge-triggered latch of XLAT signal. BLANK signal does not need to be high
to latch in new data. Figure 16 shows the On/Off data input timing chart.
Delay Between Outputs
The TLC5924 has graduated delay circuits between outputs. These delay circuits can be found in the constant
current block of the device (see Functional Block Diagram). The fixed delay time is 20 ns (typical), OUT0 has no
delay, OUT1 has 20 ns delay, OUT2 has 40 ns delay, etc. This delay prevents large inrush currents, which
reduce power supply bypass capacitor requirements when the outputs turn on. The delay works during switch on
and switch off of each output channel. LEDs that have not turned on before BLANK is pulled high will still turn on
and off at the determined delayed time regardless of the state of BLANK. Therefore, every LED will be
illuminated for the amount of time BLANK is low.
Pre-Charge FET On/Off Timing
The pre-charge FETs turn on at the same time; and, they turn on at the time the last output that is on turns off.
All pre-charge FETs turn off just after BLANK signal becomes low level, regardless of on/off data of each output.
Figure 9 shows the example of BLANK and OUTn timing.
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BLANK
OUT0
VUP
Current ON
OFF
tpd2
td x 14
ON
tpd2
td x 14
OFF
OUT14
OUT15
ON
Pre-charge Period
Figure 9. Timing Chart of BLANK and OUTn
(On/Off Data Condition: OUT0=H, OUT14=H, OUT15=L)
VUP: Pre-Charge Power Supply
VUP is a pre-charge power supply terminal. The pre-charge voltage should be supplied to this terminal for
normal operation. When VUP terminal is open, TLC5924 keeps OUT0-15 open. TLC5924 has two VUP pins as
shown in the Terminal Functions Table. Both VUP pins should be connected to the pre-charge power supply as
shown in Figure 10.
Pre-Charge Power Supply
VUP
VUP
TLC5924
Figure 10. VUP Power Supply
Serial Interface Data Transfer Rate
The TLC5924 includes a flexible serial interface, which can be connected to a microcontroller or digital signal
processor. Only 3 pins are required to input data into the device. The rising edge of SCLK signal shifts the data
from SIN pin to internal shift register. After all data is clocked in, a rising edge of XLAT latches the serial data to
the internal registers. All data is clocked in with MSB first. Multiple TLC5924 devices can be cascaded by
connecting SOUT pin of one device with SIN pin of following device. The SOUT pin can also be connected to
controller to receive LOD information from TLC5924.
10
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V
V
V
V
V
CC
(LED)
(LED)
(LED)
(LED)
100 k
OUT0
OUT15
SOUT
OUT0
OUT15
SOUT
SIN
SIN
SIN
XERR
SCLK
XLAT
XERR
SCLK
XLAT
XERR
SCLK
XLAT
V
V
CC
CC
100 nF
100 nF
TLC5924
TLC5924
Controller
MODE
BLANK
MODE
BLANK
MODE
BLANK
IREF
IREF
SOUT
IC 0
IC n
5
Figure 11. Cascading Devices
Figure 11 shows a example application with n cascaded TLC5924 devices connected to a controller. The
maximum number of cascaded TLC5924 devices depends on application system and data transfer rate.
Equation 3 calculates the minimum data input frequency needed.
f_(SCLK) + 112 f_(update) n
(3)
where:
f_(SCLK): The minimum data input frequency for SCLK and SIN.
f_(update): The update rate of the whole cascaded system.
n: The number of cascaded TLC5924 devices.
Operating Modes
The TLC5924 has different operating modes depending on MODE signal. Table 2 shows the available operating
modes. The values in the input shift registers, DC register and On/Off register are unknown just after power on.
The DC and On/Off register values should be properly stored through the serial interface before starting the
operation.
Table 2. TLC5924 Operating Modes Truth Table
MODE SIGNAL
LOW
INPUT SHIFT REGISTER
MODE
16 bit
On/Off Mode
HIGH
112 bit
Dot Correction Data Input Mode
11
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Error Information Output
The open-drain output XERR is used to report both of the TLC5924 error flags, TEF and LOD. During normal
operating conditions, the internal transistor connected to the XERR pin is turned off. The voltage on XERR is
pulled up to VCC through a external pull-up resistor. If TEF or LOD is detected, the internal transistor is turned
on, and XERR is pulled to GND. Since XERR is an open-drain output, multiple ICs can be OR'ed together and
pulled up to VCC with a single pull-up resistor. This reduces the number of signals needed to report a system
error.
To differentiate LOD and TEF signal from XERR pin, LOD can be masked out with BLANK = HIGH.
Table 3. XERR Truth Table
CONDITION
BLANK
ERROR INFORMATION
XERR
TEMPERATURE
TJ < T(TEF)
OUTn VOLTAGE
TEF
L
LODn
H
Don't Care
L
High-Z(1)
TJ > T(TEF)
H
L
TJ < T(TEF)
L
OUTn > V(LOD)
OUTn < V(LOD)
OUTn > V(LOD)
OUTn < V(LOD)
L
L
H
L
High-Z
L
L
L
TJ > T(TEF)
H
H
(1) Note: High-Z means high impedance
TEF: Thermal Error Flag
The TLC5924 provides a temperature error flag (TEF) circuit to indicate an over-temperature condition of the IC.
If the junction temperature exceeds the threshold temperature T(TEF) (160°C typical), TEF becomes H and XERR
pin goes to low level. When the junction temperature becomes lower than the threshold temperature, TEF
becomes L and XERR pin becomes high impedance.
LOD: LED-Open Detection
The TLC5924 has an LED-open detector to detect broken or disconnected LEDs, which should be connected to
the output. The LED-open detector pulls the XERR pin down to GND when the LED open is detected. An open
LED is detected when the following three conditions are met:
1. BLANK is low
2. On/Off data is high
3. The voltage of OUTn is less than 0.3 V (typical)
The LOD status of each output can also be read out from the SOUT pin. Figure 12 shows the LOD data format.
Table 4 shows the LOD truth table.
MSB
15
LSB
0
LOD
OUT15 OUT14 OUT13
LOD
LOD
LOD
OUT2
LOD
OUT1
LOD
OUT0
LOD Data
Figure 12. LOD Data Format
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Table 4. LOD Data Truth Table
LED
Good
Good
Bad
ON/OFF
On
LOD BIT
0
0
1
0
Off
On
Bad
Off
Key Timing Requirements to Reading LOD
•
LOD status flag
The LOD status flag becomes active if the output voltage is <0.3 V (typical) when the output sink current
turns on. There is a 1-µs time delay from the time the output sink current turns on until the time the LOD
status flag becomes valid. The timing for each channel’s LOD status to become valid is shifted by the 30 ns
channel-to-channel turn-on time. After BLANK goes low, OUT0 LOD status is valid when tpd2 + tpd4 = 60
ns + 1 µs = 1.06 µs. OUT1 LOD status is valid when tpd2 + tpd4 + td = 60 ns + 1 µs + 30 ns = 1.09 µs.
OUT3 LOD status is valid when tpd2 + tpd4 + 2*td = 1.12 µs, and so on.
•
•
LOD internal latch
The TLC5924 has an internal latch to hold each channel’s LOD status flag information, as shown in
Figure 13. When MODE is low, the LOD status information is latched into this latch on the rising edge of
XLAT. This is an edge-triggered latch. To ensure that a valid LOD status flag is latched, BLANK must be low
when XLAT goes high. After the rising edge of XLAT, changes in the status flags do not affect the values in
the LOD latch.
Loading LOD data to the input shift register
The LOD data must be transferred to the input shift register before it is available to be clocked out of SOUT.
The internal shift register has a set/reset function that is controlled by the LOD internal latch. While XLAT is
high, the LOD internal latch holds the input shift register in either set or reset, depending on the value in the
latch. This effectively puts the LOD data into the input shift register where it remains as long as XLAT is
high. The values in the input shift register are unaffected by any other signals, including SIN and SCLK while
XLAT is high. During this time, the status of OUT15 is present on SOUT.
•
•
Latching LOD data into the internal shift register
While XLAT is high, the status of OUT15 is present on SOUT. When XLAT transitions low, all data is latched
into the Input shift register, and the LOD internal latch is disconnected from the internal shift register.
Clocking LOD data out of SOUT
While XLAT is low and SCLK is low, the status of OUT15 is on SOUT. On the next rising edge of SCLK, the
status of OUT14 shifts to SOUT. Each subsequent rising edge of SCLK shifts the LOD data out of SOUT.
XLAT must stay low until all LOD data is clocked out of SOUT. See Shifting the LOD Data Out section for
more details.
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16bit LOD Status Flags
16bit LOD Internal Latch
SOUT
SIN
Input Shift Register
(FIFO Register)
GS Register
Figure 13. LOD Flags and Latches
Shifting the LOD Data Out
SOUT outputs the LOD data as shown in Figure 14, where:
•
XLAT rising edge
Holds the LOD status flag. SOUT outputs LOD OUT15 data. BLANK must be low.
XLAT = H
•
Sets or resets the input shift register depending on each LOD data.
Set/Reset function is higher priority than shifting the register value. If XLAT is high and the SCLK pin is
pulsed, all LOD data are kept in the shift register and SOUT keeps the LOD OUT15 data.
•
•
XLAT = L
Ready to shift out LOD data by SCLK. SOUT contains LOD OUT15 data at this time. BLANK can be high or
low during this time.
SCLK rising edge
SOUT outputs LOD OUT14 at the first SCLK rising edge. SOUT outputs LOD OUT13 at the second SCLK
rising edge, and continues to output the next LOD data at each SCLK rising edge.
XLAT
SCLK
LOD
LOD
LOD
LOD
SOUT
OUT15
OUT14
OUT13
OUT12
Figure 14. The LOD Data of SOUT
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Figure 15 shows the timing chart of reading LOD data.
At the rising edge of XLAT while BLANK=L, LOD status is latched into
the internal edge-triggered register.
MODE
When XLAT=H, the internal edge-triggered register
sets or resets the input shift registe. r
XLAT
SCLK
SIN
SOUT
1510ns max
1510ns max
BLANK
tpd2: 60ns max
tpd2: 60ns max
OUT0
LED open
OUT15
td x 15 = 450ns max
td x 15 = 450ns max
XERR
tpd4: 1000ns max
>1000ns
tpd4: 1000ns max
>1000ns
Figure 15. Timing Chart of Reading LOD Data
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Figure 16. Timing Chart Example for ON/OFF Setting to Dot-Correction
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TYPICAL CHARACTERISTICS
REFERENCE RESISTOR
OUTPUT CURRENT
vs
REQUIRED OUTPUTn VOLTAGE
vs
OUTPUT CURRENT
100
90
100 k
49.6 k
V
Outn
= 1 V
DC = 127
80
70
60
10 k
I
I
= 60 mA
9.92 k
4.96 k
MAX
50
40
30
20
10
0
2.48 k
= 40 mA
= 20 mA
MAX
1.65 k
1.24 k
992
1 k
827
709
I
MAX
100
0
0.50
1
1.50
2
2.50
3
0
0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
VO− Required Output Voltage − V
I
− Output Current − A
OLC
Figure 17.
Figure 18.
POWER DISSIPATION
vs
FREE-AIR TEMPERATURE
SUPPLY CURRENT(A)
vs
FREE-AIR TEMPERATURE
6 k
70
60
50
40
30
20
TLC5924DAP
PowerPAD Soldered
5 k
4 k
3 k
2 k
1 k
0
TLC5924RHB
TLC5924DAP
PowerPAD Unsoldered
10
0
−40
−20
0
20
40
60
80
100
−50 −30 −10 10 30 50 70 90 110 130 150
T
A
− Free-Air Temperature −°C
T
A
− Free-Air Temperature − °C
Figure 19.
A. Data Transfer
= 30 MHz / All Outputs,
ON/VO = 1 V / RIREF = 600 Ω / AVDD = 5 V
Figure 20.
Power Rating – Free-Air Temperature
Figure 19 shows total power dissipation. Figure 20 shows supply current versus free-air temperature.
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