IS32LT3123 QUAD CHANNEL EXTERNAL NMOS FET HIGH CURRENT AUTOMOTIVE LED CONTROLLER WITH INTERNAL PWM DIMMING May 2020 GENERAL DESCRIPTION FEATURES The IS32LT3123 is a quad channel linear controller Low side external NMOS FETs support high capable of accurately regulating LED current with output current with independent current setting external NMOS FETs. It integrates PWM dimming for One resistor to simultaneously adjust all channels two LED brightness levels for RCL (Rear Combination for LED binning Lamp) or DRL (Daytime Running Lamp) applications. 200mV reference feedback voltage for high It is fully programmable with two LED brightness efficiency levels for the different intensity requirements, such as 4% current accuracy over -40C ~125C Stop (full brightness) and Tail dim (PWM dimming). A logic level at the PWMB pin is used to switch 5.0V to 40V supply voltage between the two brightness levels. A logic high PWMB voltage input to select between full provides the highest intensity output, while a logic low brightness and PWM dimming utilizes an internally generated PWM signal to reduce Flexible LED PWM dimming options the intensity of the LEDs light output. - Internal PWM dimming set by resistors Multiple devices also can be connected in parallel in a Programmable duty cycle, 5%~95% master-slave structure for larger lighting applications. Programmable frequency, 100Hz~1kHz - External PWM signal input dimming For added system reliability, the IS32LT3123 - Analog voltage input for PWM dimming integrates fault detection circuitry for LED open/short circuit, input over voltage and over temperature PWM slew rate control on each output to optimize conditions. The FAULTB pin is dedicated to the fault EMI performance conditions reporting and the MODE pin can control Robust fault protection the action of the device in case of a fault condition. - Fault reporting LED string open/short The device also supports the NTC resister to monitor the LED string temperature. In case of the Thermal shutdown temperature exceeds the setting threshold, the device - LED string over temperature thermal rolloff will reduce the drive current to protect the LED string. - Input over voltage current derating - Controller junction over temperature thermal The device package is an eTSSOP-24 with exposed rolloff pad for enhanced thermal dissipation. Multiple parallel IC operation for higher number of strings with fault condition and PWM dimming sync AEC-Q100 Qualified APPLICATIONS Automotive and avionic lighting Rear combination light (STOP/TAIL lights) Center high mounted stop light Position light Daytime running light (DRL) Turn light Lumissil Microsystems www.lumissil.com 1 Rev. A, 05/06/2020 IS32LT3123 TYPICAL APPLICATION CIRCUIT Figure 1 Typical Application Circuit of Internal PWM Dimming Figure 2 Typical Application Circuit of External PWM Dimming Lumissil Microsystems www.lumissil.com 2 Rev. A, 05/06/2020