MICROCHIP AT9919K7-G

AT9919 is a PWM controller IC designed to drive high-brightness LEDs using a buck topology. It operates from an input voltage of 4.5 VDC to 40 VDC and employs hysteretic control with a high-side current sense resistor to set the constant output current. The operating frequency range can be set by selecting the proper inductor. Operation at high switching frequency is possible since the hysteretic control maintains accuracy even at high frequencies. This permits the use of small inductors and capacitors, minimizing space and cost in the overall system. LED brightness control is achieved with PWM dimming from an analog or PWM input signal. Unique PWM circuitry allows true constant color with a high dimming range. The dimming frequency is programmed using a single external capacitor. AT9919 comes in a small, 8-Lead WDFN package and is qualified for LED lighting applications. AT9919 passes the automotive AEC-Q100 reliability testing.

AT9919 is a step-down constant-current high-brightness LED (HB LED) driver. The device operates from a 4.5V to 40V input voltage range and provides the gate driver output to an external N-channel MOSFET. A high-side current sense resistor sets the output current and a dedicated PWM dimming input (DIM) allows for a wide range of dimming duty ratios. The PWM dimming could also be achieved by applying a DC voltage between 0V and 2V to the analog dimming input (ADIM). In this case, the dimming frequency can be programmed using a single capacitor at the RAMP pin. The high-side current sensing scheme minimizes the number of external components while delivering LED current with a ±8% accuracy, using a 1% sense resistor.

• AEC-Q100 Qualified
• Hysteretic Control with High-side Current Sensing
• Wide Input Voltage Range: 4.5V to 40V

• 90% Efficiency

• Typical ±5% LED Current Accuracy
• Up to 2 MHz Switching Frequency
• Adjustable Constant LED Current
• Analog or Pulse-Width Modulation (PWM) Control Signal for PWM Dimming
• Overtemperature Protection
• -40℃ to +125℃ Operating Temperature Range

• LED Lighting Applications
• Automotive Applications