High-Performance LED Driver Circuit Design Using the Microchip HV9911NG-G-M901

The demand for efficient and reliable solid-state lighting continues to grow across industrial, automotive, and consumer applications. Designing a high-performance LED driver is critical to ensuring longevity, stability, and optimal light output. The Microchip HV9911NG-G-M901 integrated circuit offers a robust and flexible solution for constructing such drivers, particularly those requiring high voltage input and precise current regulation.

This controller is a constant-frequency, peak current mode control device specifically engineered for driving LEDs. Its ability to operate from an input voltage range of 8V to 450V makes it exceptionally versatile, suitable for applications ranging from low-voltage DC systems to direct off-line rectified mains. A key feature of the HV9911 is its use of a pulse-width modulation (PWM) control scheme, which allows for highly efficient regulation of the current supplied to the LED string.

The typical circuit configuration utilizing the HV9911 is a boost converter topology, ideal for situations where the required LED string voltage is higher than the input supply. The core of the design revolves around regulating the current, not the voltage. An external sense resistor (R_sense) is placed in series with the LEDs, and the voltage drop across this resistor is fed back to the CS (Current Sense) pin of the IC. The internal comparator then adjusts the duty cycle of the gate drive output to maintain a constant peak current, as defined by the voltage reference and the external resistor value. This method ensures precise LED current regulation, which is paramount for consistent luminosity and long-term reliability.

The HV9911NG-G-M901 provides several critical protection and control functions. It includes an undervoltage lockout (UVLO) to prevent operation at insufficient voltage levels and a programmable soft-start circuit to mitigate inrush current during startup. The gate drive output is capable of directly driving an external MOSFET, simplifying the power stage design. Furthermore, the device offers a PWM dimming capability through its LD (Dimming) pin. By applying an external PWM signal to this pin, the LED current can be dimmed over a wide range without altering the color temperature, a significant advantage for many lighting scenarios.

When laying out a printed circuit board (PCB) for this driver, careful attention must be paid to minimizing high-frequency switching noise loops. The path containing the switching MOSFET, the output diode, and the output capacitor should be as short and direct as possible. Proper grounding, especially for the sensitive current sense circuitry, is crucial to avoid noise coupling and ensure stable operation.

In conclusion, the HV9911NG-G-M901 from Microchip provides a comprehensive and high-performance foundation for advanced LED driver designs. Its high input voltage capability, accurate constant-current control, and integrated features like PWM dimming make it an excellent choice for demanding lighting applications.

ICGOOODFIND: The HV9911NG-G-M901 is a highly integrated and versatile LED driver controller, prized for its wide input voltage range, robust peak current mode control, and excellent dimming performance, making it a top choice for efficient and reliable high-voltage LED driving solutions.

Keywords:

1. Constant-Current Regulation

2. Boost Converter

3. PWM Dimming

4. High-Voltage Input

5. Peak Current Mode Control