IS32LT3129 TRIPLE CHANNEL LINEAR LED DRIVER WITH I2C INTERFACE AND FADE ON/OFF January 2020 GENERAL DESCRIPTION FEATURES The IS32LT3129 is a programmable triple channel Operating voltage range, 5V to 42V linear current regulator two channels of up to 150mA 1MHz I2C-compatible interface each for LED lighting and a single channel of up to Dual channel current sources 30mA for illuminating switches. The device operates - Individual programmable current via a single as a fully configurable theatrical dimming LED driver external resistor and I2C External resistors will program the current levels as - Configurable from 20mA to 150mA well as the LED fade ON/OFF ramp rate. Single channel 30mA (Max.) current source for In additional, the I2C interface supports writing/reading switch illumination function for MCU to select switch type (momentary EN input supports either momentary contact or contact or latched), individually configure the output latched switch current levels and fade on/off ramp rate, or get the - Input is debounced and latched state of device and the fault flag of open/short circuit - Higher priority than I2C input and thermal shutdown. - Gamma corrected Fade ON/OFF algorithm An integrated debounce and latch circuit on the - Pull down resistors or I2C set independent fade channel enable pin (EN1/2) is enabled when the ON and OFF ramp time device is configured for a momentary contact switch Selectable internal PWM source interface. The other option is to configure the EN pins - Internal 220Hz PWM source with Gamma to accept a static level signal for operation with latched corrected algorithm for automatic dimming the switches. If configured for Internal-PWM-Dimming current source mode, the integrated PWM source will be triggered by Fault Protection: an I2C command. This enables LED dimming without - Fault Reporting the need for an external PWM input. The EN inputs have a higher priority and will override internal PWM. LED strings short See Figure 63~69 for the details. LED strings open 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 value after the EN1/2 pins are triggered or send I2C Operating temperature range from -40C ~ +125C commands (when configured for AEC-Q100 Qualified Internal-PWM-Dimming mode). The same controller APPLICATIONS causes the LED brightness to gradually ramp down to zero if the EN1/2 pins are triggered or send I2C Automotive Interior: commands (when configured for - Map/Dome light Internal-PWM-Dimming mode) while the output - Puddle lamp in doors channel is ON. The fade ramp can be interrupted - Glove box light mid-cycle before completion of the ramp cycle. - Vanity mirror light The IS32LT3129 is targeted at the automotive market 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, 01/07/2020 IS32LT3129 TYPICAL APPLICATION CIRCUIT V Battery 18 19 VCC OUT1 20 10 F OUT2 1 8 OUT3 VIO 47k 2k 2k 1 F 470 9 SCL Backlight LED 470 10 SDA IS32LT3129 Micro 7 Controller FAULTB 2 EN3 12 R ISET1 ISET1 11 13 R ISET2 AD ISET2 S1 4 14 R ISET3 EN1 ISET3 Momentary R S2 3 15 TSET UP Contact EN2 TSET UP R 6,17 16 TSET DN GND TSET DN Figure 1 Typical Application Circuit with Momentary Contact Switch V Battery 18 19 VCC OUT1 20 10 F OUT2 1 8 OUT3 VIO 47k 2k 2k 1 F 470 9 SCL Backlight LED 470 10 SDA IS32LT3129 Micro 7 Controller FAULTB 2 R EN3 12 ISET1 V V ISET1 CC IO 11 13 R ISET2 AD ISET2 S1 4 14 R ISET3 EN1 ISET3 Latched S2 3 15 R TSET UP Switch EN2 TSET UP 6,17 16 R TSET DN GND TSET DN Figure 2 Typical Application Circuit with Latched Switch Lumissil Microsystems www.lumissil.com 2 Rev. A, 01/07/2020