IS32LT3126 150MA DUAL CHANNEL LED DRIVER WITH FAULT DETECTION DESCRIPTION FEATURES The IS32LT3126 is a dual linear programmable current Four output channels can source up to 150mA regulator consisting of 2 independently controlled each output channels each channel is capable of sourcing Dual channel: each channel can source up to 150mA. Both channels can be combined to provide a 150mA and the two channels combined to source total of 300mA. It supports PWM dimming of both up to 300mA channels via power supply modulation (PSM). It also External resistors individually set source current features ENx pins to individually PWM dim and 4% channel to channel current matching independently adjusts the average output current for Individually programmable VCC under voltage each channel. The max current for each channel is set lockout to match the LED stack for PSM operation with its corresponding external resistor. Individual PWM dimming The UVx pins set the VCC under voltage lockout of Shared fault flag for multiple devices operation each channel to match the LED stack for high side Fault protection with flag reporting: PWM dimming operation. In addition, the IC integrates Single LED short (optional to turn off all LEDs) fault protection for LED open/short, ISETx pin LED string open/short open/short and over temperature condition for robust operation. Detection of these failures is reported by OUTx pins short to VCC/GND FAULTB pin. When a fault is detected the device will ISETx pins open/short disable itself and output an open drain low signal. Over temperature current rollback (no reporting) Multiple devices can have their FAULTB pins Thermal shutdown connected to create a one-fail-all-fail condition. For External CSTOR capacitor keeps fault status multiple LED string applications, the device can detect during start/stop operation a single LED short. The single LED short detection is eTSSOP-16 package set by a resistor divider on the STx pins. A single LED Operating temperature range from -40C ~ +125C short failure is reported by the separate FAULTB S AEC-Q100 Qualified pin. The IS32LT3126 is targeted at the automotive market RECOMMENDED EQUIPMENT with end applications to include interior and exterior lighting. For 12V automotive applications the low 12V,1A DC power supply dropout driver can support one to several LEDs on the output channels. ABSOLUTE MAXIMUM RATINGS QUICK START 40V power supply Caution: Do not exceed the conditions listed above, otherwise the board will be damaged. PROCEDURE The IS32LT3126 evaluation board is fully assembled and tested. Follow the steps listed below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. 1) Connect negative terminal of the power supply to the GND and the positive terminal to the VCC. 2) Each output current is individually set by four different value resistors (R ). Close jumper of ISETX Figure 1: Photo of IS32LT3126 Evaluation Board J8~J15 to select different output current for each channel. Table 1 Current Setting Jumper Jumper Jumper Jumper J8,J12 J9,J13 J10,J14 J11,J15 I =150mA I =100mA I =50mA I =25mA OUT1 OUT1 OUT1 OUT1 I =150mA I =100mA I =50mA I =25mA OUT2 OUT2 OUT2 OUT2 Lumissil Microsystems www.lumissil.com 1 Rev. A, 11/09/2018 IS32LT3126 150MA DUAL CHANNEL LED DRIVER WITH FAULT DETECTION 3) J16, J17 are used to connect the IS32LT3126s together. In the case of single LED short is outputs to the onboard LED strings (LED1~LED6). detected, the FAULTB S pin pulls down the Use the green terminal blocks to connect the FAULTB pin together that turns off the no fault external LED strings. Remove the corresponding condition channel. jumper J16 and J17 to disable the onboard LED 6) The on board LED string can be adjusted from 1 string. to 3 LEDs by using header J3, J4, J5, J6. Close Note: Connecting an external LED string without the jumper to pins1-2 of J3,J4,J5,J6 disables the removing the onboard string jumper header will drive both corresponding LED2,LED3,LED5,LED6.To enable onboard and external LED strings in parallel resulting in all the LEDs close the jumper to pins 2-3 of lower current drive to the LED string. J3,J4,J5,J6 or remove jumper. 4) Close jumper J1, J2 to pull EN1/EN2 pins via 7) R19, R20, C8, ZD1 and LED7 are used as fault 100k resistor to VCC. If apply a PWM signal to reporting indicator. EN1/2 pins, please remove corresponding jumper Note: This circuit is not necessary for real application. J1 and J2, otherwise the PWM source may be damaged. 5) Close jumper J7, FAULTB and FAULTB S are tied ORDERING INFORMATION Part No. Temperature Range Package IS32LT3126-ZLA3-EB -40C ~ +125C (Automotive) eTSSOP-16, Lead-free Table 1: Ordering Information For pricing, delivery, and ordering information, please contact Lumissils analog marketing team at analog Lumissil.com or (408) 969-6600. Table 2 Jumper Setting Jumper Options Settings Close jumper: EN1, EN2 pin pulled up to VCC via a 100k EN setting. If use PWM dimming, J1,J2 resistor and enable the corresponding output. please remove jumper J1, J2. Open jumper: PWM dimming Close pin1-2 : disable the corresponding LED J3~J6 Number of LED control Close pin2-3 : enable the corresponding LED Close jumper: FAULTB and FAULTB S are tied together J7 FAULTB and FAULTB S setting Open jumper: FAULTB and FAULTB S are separated Close jumper to select corresponding resistor. Refer to J8~J15 Output current setting. table 1 for details Close jumper: enable the corresponding onboard LED string J16, J17 Onboard LED strings select. Open jumper: disable the corresponding onboard LED string EVALUATION BOARD OPERATION (13.33kR 80k ) ISET OUTPUT CURRENT SETTING R need to be chosen 1% accuracy resistor with ISET good temperature characteristic to ensure stable A single resistor (R ) controls the maximum output ISETx output current. current for each channel. The resistor value for a The device is protected from an output overcurrent specific current level is calculated using the following Equation (1): condition caused by a too low value R , by ISETx internally limiting the maximum current to I . OUT L 2000 R (1) ISET I SET Lumissil Microsystems www.lumissil.com 2 Rev. A, 11/09/2018