IS31BL3506B-STLS2-TR ISSI

IS31BL3506B 1.0MHZ BOOST CONVERTER WITH 35V INTERNAL MOSFET SWITCH April 2013 GENERAL DESCRIPTION FEATURES IS31BL3506B is a boost converter featuring an Supply voltage: 2.7V~5.5V integrated MOSFET switch designed for driving series Built-in soft start strings of LED or other device. Input operating voltage Drive series strings of 8 LEDs range is 2.7V~5.5V. The device regulates the LED load PWM or DC voltage dimming current is set using an external, low value sensing Frequency of PWM is 500Hz ~ 500kHz resistor. The device adjusts the PWM duty cycle of the 1.0MHz high speed switching frequency switch to maintain the voltage at the FB pin at a value of 0.2V. The IS31BL3506B operates at a constant 200mV feedback voltage switching frequency of 1.0MHz to allow for small Integrated high power MOSFET component size. IS31BL3506B features an over Over voltage protection voltage shutdown pin which prevents the output -40C ~ +85C working temperature range voltage from exceeding 35V (typ.) in the case of an TSOT-23-6 and SOT-23-6 package open circuit condition. The device is offered in a tiny TSOT-23-6 and SOT-23-6 package and a temperature APPLICATIONS rating from -40C ~ +85C. Small LCD Backlights Notebook PC GPS TYPICAL APPLICATION CIRCUIT Figure 1 Constant current white LED driver using PWM at the EN pin to control intensity Note 1: C must be rated for 50V. Smaller values of output capacitance will cause the LED current ripple to increase. OUT Note 2: The resistor R should be placed as close as possible to the FB pin to prevent the EMI. EST Note 3: The high level of PWM signal for EN pin should last at least 200ns when power on, or the IC wont start up. Lumissil Microsystems www.lumissil.com 1 Rev. A, 04/15/2013 IS31BL3506B VBattery L1 D1 2.7~5.5V 10 H 2.2 F 0.1 F 6 1 COUT VCC LX 1 F 5 (50V) (4~6)2 PWM Signal OUT LEDs 4 Micro IS31BL3506B EN Controller 3 FB 100k 2 RSET GND 5 Figure 2 Constant current white LED driver using PWM at the EN pin to control intensity (4~6)2 LEDs VBattery L1 D1 2.7~5.5V 10 H VOUT =VFB (R1 +RSET)/RSET 2.2 F 0.1 F 6 1 COUT VCC LX 1 F 5 (50V) Load R1 OUT 4 Micro IS31BL3506B EN Controller 3 FB 100k 2 RSET GND Figure 3 Constant output voltage for general purpose use Figure 4 Constant output current with DC dimming input Lumissil Microsystems www.lumissil.com 2 Rev. A, 04/15/2013