IS32LT3181

IS32LT3181
RCL DUAL INTENSITY, SIX CHANNEL LED DRIVER WITH FAULT DETECTION
Advance Information
June 2015
GENERAL DESCRIPTION
FEATURES
The IS32LT3181 is a six channel linear current
regulator for automotive rear tail light applications such
as RCL (Rear Combination Lamps) and CHMSL
(Center High Mounted Stop Lamps). It is fully
programmable with two LED brightness levels for the
different intensity requirements of “stop” bright (DC
mode) and “tail” dim (PWM mode).


A logic level at the PWM pin is used to select between
the tail and stop output conditions. The stop condition
provides the highest intensity output, while the tail
condition utilizes an internally generated PWM signal
to reduce the intensity of the LEDs’ light output.

An active low fault output signal reports a device error
condition. The FAULTB pin of several devices can be
tied together to disable all the output stages when a
fault is detected by any one of the devices.


The sink current at the OUTx pins is easily set with a
single resistor at the STOP pin. The constant-current
sink outputs can be combined in parallel to create
higher current-driving capability on a single string. A
second resistor at the TAIL pin sets the duty cycle of
the internal PWM oscillator for dimming the LED output
when operating in the tail condition.


An external FET (optional) can be implemented for
operation with wide varying supply voltages to
minimize device thermal dissipation.
Operating voltage from 6V to 16VDC
- Withstand 50V load dump
6 constant-current channel sinks
- Adjustable from 10mA to 75mA per channel
- Channel paralleling for higher current
- Low dropout voltage of 0.8V@35mA
- Slew rate control on each output for better EMI
performance
Integrated PWM dimming engine provides two
LED brightness levels without external logic
- Tail duty cycle programmable from 1% to 95%
- PWM logic level input selects between full
brightness and PWM dimming levels
Support for optional FET to minimize device power
consumption
Open Drain FAULTB reporting pin
- Programmable FAULTB delay time
- Programmable UVLO threshold
- LED open circuit detection
- STOP pin over current protection
- Over temperature protection
Device disable upon fault detection
- Parallel connection to other devices
AEC-Q100 qualification (pending)
APPLICATIONS





The IS32LT3181 is offered in an eTSSOP-16 package.
Rear Combinational Lamp (RCL)
Center High Mount Stop Light (CHMSL)
Daytime running lamp
Fog lamps
Turn signal
TYPICAL APPLICATION CIRCUIT
1k
VSTRING
Q1
TAIL
0.1 F
50
3
STOP
220nF
CVCC
1 F
R1
10k
2
1
6
R2
5
7
10nF
8
RSTOP RTAIL
3.09k 7.72k
9
ERC
VCC
UVLO
OUT1
16
RFB1
8.87k
FAULTB
IS32LT3181
PWM
STOP
TAIL
DELAY
OUT6
FB
GND
10
4
13
RFB2
1k
Figure 1 Typical Application Circuit
Integrated Silicon Solution, Inc. – www.issi.com
Rev. 00C, 06/09/2015
1
IS32LT3181
TAIL
CVCC
1 F
STOP
R1
2
3
1
VCC
ERC
UVLO
10k
R2
OUT1
5
6
10nF
7
RSTOP RTAIL
3.09k 7.72k
8
9
16
RFB1
10k
PWM IS32LT3181
FAULTB
STOP
TAIL
DELAY
OUT6
FB
GND
10
4
13
Figure 2 Typical Application Circuit (Without external FET)
Figure 3 Several Devices Connect FAULTB Pin In Parallel
Integrated Silicon Solution, Inc. – www.issi.com
Rev. 00C, 06/09/2015
2