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