Preliminary IS31LT3515 High Voltage LED Lighting Driver for Buck, Boost or Buck-boost Topology September 2012 General Description Features The IS31LT3515 is a current mode PWM controller Wide voltage: Vin up to 40V, Vout up to higer designed to drive an external MOSFET for high current Buck, Boost or Buck-Boost operation LED applications. With a current sense amplifier Easy dimming: Analog, PWM or PWM converting to threshold of 250mV, the LED current is programmable with one external current sense resistor. The analog with an external capacitor Output over voltage protection(OVP) IS31LT3515 is ideal for buck, boost or buck-boost Internal soft start to avoid inrush current operation. With 250kHz operating frequency (typical, Current mode PWM with an 250kHz operating and this frequency can be set up by external resistor), frequency(typical, RSET=150Kohms) the external inductor and capacitors can be small while Output short circuit protection maintaining high efficiency. VIN under voltage lock out and Over temperature Dimming can be either analog or PWM digital. Input DC protection(OTP) voltage from LD pin for analog dimming. Input PWM signal from PWM pin can get either analog dimming or Applications PWM dimming. General industrial high power LED lighting The SN3515 is available in SOP-16 package and Desk lights and room lighting, street lighting QFN-16 3*3 package. Display backlight Typical Application Circuit Buck Boost configuration Copyright © 2011 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 10/12/2012 1 Preliminary IS31LT3515 Pin Configuration Package Pin Configurations(Top view) SOP-16 Pin Description Pin No. Pin Name Function 1 VCC 2 PWMD PWM dimming input. The PWM signal will convert to analog signal with an external capacitor. (Low is enable, internal have pull down resistor) 3 EN Enable Pin. Floating(pull down internal), enable; pull to high, shutdown mode 4 LD Analog dimming input. 5,12 GND Ground 6 OPT Structure selection. Floating: boost. connect to ground: buck-boost 7 FSET With an external RFSET=150kohms) 8 CSsense 9 OVP Over voltage protect, this pin voltage exceed 1.23V, GATE will pull low. 10 ISN The LED current sense amplifier negative input 11 ISP The LED current sense amplifier positive input 12 GND Ground 13 CS 14 FAULT This pin is the same as PWM signal and when ISP-ISN>0.5v, pulled to ground (short circuit is detected) 15 GATE Gate drive to the external MOSFET(12V) 16 VCCout The power supply pin resistor to set operation frequency. (250KHz, current sense mirror pin, connect a res to CS pin(1:5000) MOSFET current sense LDO 12V output , need an external cap(1uF) ORDERING INFORMATION INDUSTRIAL RANGE: -40°C TO +85°C Order Part No. Package QTY/Reel IS31LT3515-GRLS2-TR SOP-16, Lead-free 2500 Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 10/12/2012 2