AT9919K7-G Microchip

AT9919 Hysteretic Buck High-Brightness LED Driver with High-Side Current Sensing Features General Description Hysteretic Control with High-side Current Sensing The AT9919 is a PWM controller IC designed to drive high-brightness LEDs using a buck topology. It Wide Input Voltage Range: 4.5V to 40V operates from an input voltage of 4.5 VDC to 40 VDC >90% Efficiency and employs hysteretic control with a high-side current Typical 5% LED Current Accuracy sense resistor to set the constant output current. Up to 2 MHz Switching Frequency The operating frequency range can be set by selecting Adjustable Constant LED Current the proper inductor. Operation at high switching Analog or Pulse-With Modulation (PWM) Control frequency is possible since the hysteretic control Signal for PWM Dimming maintains accuracy even at high frequencies. This Overtemperature Protection permits the use of small inductors and capacitors, minimizing space and cost in the overall system. 40C to +125C Operating Temperature Range LED brightness control is achieved with PWM dimming Applications from an analog or PWM input signal. Unique PWM circuitry allows true constant color with a high dimming LED Lighting Applications range. The dimming frequency is programmed using a single external capacitor. The AT9919 comes in a small, 8-lead DFN package and is qualified for LED lighting applications. Package Type 8-lead DFN (Top View) CS 1 8 GATE VIN 2 7 GND GND RAMP 3 6 VDD ADIM 4 5 DIM See Table 2-1 for pin information. 2016 Microchip Technology Inc. DS20005595A-page 1AT9919 Functional Block Diagram VIN REGULATOR VDD + GATE - CS DRIVER CURRENT SENSE COMPARATOR GATE + BANDGAP DIM REF - UVLO COMPARATOR GND PWM RAMP RAMP - 0.1~1.9V + ADIM AT9919 DS20005595A-page 2 2016 Microchip Technology Inc.