IS32LT3128A-ZLA3-TR ISSI

IS32LT3128A TRIPLE CHANNEL LINEAR LED DRIVER WITH FADE ON/OFF AND PWM DIMMING June 2019 GENERAL DESCRIPTION FEATURES The IS32LT3128A is a programmable triple channel Operating voltage range, 5V to 42V linear current regulator two channels of up to 150mA Dual channel current sources each for LED lighting and a single channel of up to - Individual programmable current via a single 30mA for illuminating switches. The device operates external resistor as a fully configurable theatrical dimming LED driver - Configurable from 20mA to 150mA no microcontroller is required. External resistors will Single channel 30mA (Max.) current source for program the current levels as well as the LED fade switch illumination ON/OFF ramp rate. Additional configuration such as EN input supports either momentary contact or PWM source (internal or external), polarity (positive or latched switch negative) and switch type (momentary contact or - Input is debounced and latched latched) are selectable via the MODE1/2 pins. - Lower priority than PWM input An integrated debounce and latch circuit on the - Gamma corrected Fade ON/OFF algorithm channel enable pin (EN1/2) is enabled when the - Pull down resistors set independent fade ON and device is configured for a momentary contact switch OFF ramp time interface. The other option is to configure the EN pins Selectable external or internal PWM source to accept a static level signal for operation with latched - External PWM directly drives the current source switches. A VCC level PWM dimming signal can be connected to the PWM input pin to directly drive both - Internal 220Hz PWM source with Gamma corrected algorithm for automatic dimming the LED channels. If configured for Internal-PWM-Dimming mode, the integrated PWM current source source will be triggered by a PWM pin voltage level. - Support both positive and negative polarity PWM This enables LED dimming without the need for an Fault Protection: external PWM input. The PWM input have a higher - Fault Reporting priority and will override the EN inputs. See Figure LED strings short 60~66 for the details. Over temperature thermal shutdown The device integrates a 63 step fade ON/OFF - ISET pin shorted to GND algorithm (Gamma correction) which causes the output - Over temperature current roll off LED brightness to gradually ramp up to the full source AEC-Q100 Qualified value after the EN1/2 or PWM (when configured for Operating temperature range from -40C ~ +125C Internal-PWM-Dimming mode) pins are triggered. The same controller causes the LED brightness to APPLICATIONS gradually ramp down to zero if the EN1/2 or PWM (when configured for Internal-PWM-Dimming mode) Automotive Interior: pins are triggered while the output channel is ON. The - Map/Dome light fade ramp can be interrupted mid-cycle before - Puddle lamp in doors completion of the ramp cycle. - Glove box light The IS32LT3128A is targeted at the automotive market - Vanity mirror light with end applications to include map and dome lighting as well as exterior accent lighting. For 12V automotive applications the low dropout driver can support 1 to 3 LEDs per channel. It is offered in a small thermally enhanced eTSSOP-20 package. Lumissil Microsystems www.lumissil.com 1 Rev.A, 05/06/2019 IS32LT3128A TYPICAL APPLICATION CIRCUIT V Battery 18 19 VCC OUT1 20 10 F OUT2 R PWM 1 10k 5 OUT3 PWM PWM 50Hz~300Hz C PWM 3.3nF Backlight LED 2 7 EN3 FAULTB Host 4 EN1 R Momentary IS32LT3128A FAULTB 3 8 Contact EN2 VIO 11 12 POL 1 F ISET1 9 13 MODE1 ISET2 10 14 MODE2 R R R ISET1 ISET2 ISET3 ISET3 R 15 TSET UP TSET UP R 6 16 TSET DN GND TSET DN 17 Figure 1 Typical Application Circuit Configured for Momentary Contact Switch And External PWM Dimming V Battery 18 19 VCC OUT1 20 10 F OUT2 R PWM 1 10k 5 OUT3 High or Low PWM Level C PWM 3.3nF Backlight LED 2 7 V EN3 FAULTB Host CC 4 EN1 IS32LT3128A R Latched FAULTB 3 8 Switch EN2 VIO 11 12 POL 1 F ISET1 9 13 MODE1 ISET2 10 14 MODE2 R R R ISET3 ISET1 ISET2 ISET3 R 15 TSET UP TSET UP R 6 16 TSET DN GND TSET DN 17 Figure 2 Typical Application Circuit Configured for Latched Switch And Internal PWM Dimming Note 1: The resistor R is a fixed 10k , do not change value. C is optional to minimize electromagnetic susceptibility. PWM PWM Lumissil Microsystems www.lumissil.com 2 Rev.A, 05/06/2019