IS31LT3117 53V, 350MA, 4-CHANNEL CONSTANT CURRENT REGULATOR WITH OTP DESCRIPTION RECOMMENDED EQUIPMENT The IS31LT3117 is a 4-channel, linear regulated, 6.0V~53V, 2A DC power supply constant current LED driver which can sink 4 equal One digital voltmeter currents of up to 350mA per channel to drive high Four series-connected HB LED strings rated no brightness LEDs over an input voltage range of 6V to less than 100mA 53V, while maintaining an output leakage current of A current probe to measure the HB LED current less than 1uA. The sink current is easily programmed using a single external resistor. The current sinks of ABSOLUTE MAXIMUM RATINGS the IS31LT3117 may be connected in parallel to allow greater than 350mA of LED current, ie, all four VLEDx 53V power supply pins tied together for a maximum 1.4A sink available for one LED string. See limitations in the LED Caution: Do not exceed the conditions listed above, otherwise the board will be damaged. CURRENT SETTING section. The IS31LT3117 also features a PWM input to enable simple dimming control using a digital control signal. EVALUATION BOARD OPERATION The evaluation board is configured to operate each HBLED string (CHx) at 100mA. The operating current FEATURES is set by the resistor value at IS31LT3117 pin 8. See 6V to 53V input supply voltage range LED CURRENT SETTING section of the datasheet for guidance in calculating resistor values for specific Up to 1.4A total sink current currents. Over temperature protections Thermal current regulation above 130C Sink current matching 3% between channels PROCEDURE PWM dimming and Shutdown control input The IS31LT3117 evaluation board is fully assembled Very few external components and tested. Follow the steps listed below to verify board operation. QUICK START Caution: Do not turn on the power supply until all connections are completed. 1) Connect each HBLED string as follows: CHx: Connect an HBLED strings cathode to the CHx of CON3 and the anode to the CON2, Where x is 1, 2, 3 and 4. Unused CHx inputs should be connected to GND. 2) Calculate the VCC, recommended value is 0.5V to 1V higher than the sum of the LED strings total forward voltage drop. For example, if the LED strings total forward voltage is 9V 100mA, the recommended VCC is 10V. Note: Selecting an input voltage much higher than the LED strings total forward voltage will cause a high IS31LT3117 power dissipation which may lead to device shutdown. 3) Insert the current probe between the CHx terminal Figure 1: Photo of IS31LT3117 Evaluation Board (CON3) and the cathode of the CHx LED string to measure the HBLED current 4) JP1 is used to configure the PWM signal input mode. When JP1 is ON the IS31LT3117 is enabled and no external PWM signal should be connected. When JP1 is OFF the IS31LT3117 must be driven by an external PWM signal source. Caution: Always remove JP1 when driving the IS31LT3117 with an external PWM source. JP1 ON pulls up the TP1 pin to a possibly high VCC voltage that may damage the PWM signal source. Lumissil Microsystems www.lumissil.com 1 Rev.B, 07/16/2014 IS31LT3117 53V, 350MA, 4-CHANNEL CONSTANT CURRENT REGULATOR WITH OTP 5) Verify that the VCC is 10V and connect the VCC and GND to CON1. 6) Turn on the power supply (VCC) and measure the HBLED current using the current probe and verify all currents are equal. ORDERING INFORMATION Part No. Temperature Range Package IS31LT3117-ZLS4-EB -40C ~ +125C (Industrial Range) eTSSOP-16, Lead-free Table1: Ordering Information For pricing, delivery, and ordering information, please contact Lumissils analog marketing team at analog Lumissil.com or (408) 969-6600 Lumissil Microsystems www.lumissil.com 2 Rev.B, 07/16/2014