High-Performance LED Driver Circuit Design Using the Microchip HV9910CLG-G

The demand for efficient and reliable solid-state lighting has propelled the development of advanced LED driver circuits. Among the various controller ICs available, the Microchip HV9910CLG-G stands out as a highly flexible, high-performance solution for a wide range of lighting applications. This article explores the key design considerations and advantages of implementing a driver circuit using this innovative controller.

The HV9910CLG-G is a constant-current, pulse-width modulation (PWM) controller designed to operate from a wide input voltage range (8V to 450V), making it suitable for both low-voltage and universal AC input (e.g., 85VAC to 265VAC) applications. Its primary function is to regulate a consistent current through an LED string, which is paramount for achieving uniform luminosity and extended LED lifespan. Unlike simple linear drivers, it enables highly efficient switching-mode power conversion, significantly reducing heat generation and power loss.

A typical application circuit using the HV9910CLG-G is a boost (step-up) converter topology, ideal for driving long series strings of LEDs where the total forward voltage exceeds the input supply. The core operation revolves around controlling an external power MOSFET switch. The IC generates a fixed-frequency PWM signal, whose duty cycle is dynamically adjusted based on feedback from a simple sense resistor (R_sense) in the LED current path. This closed-loop control mechanism ensures precise current regulation despite variations in input voltage or the forward voltage of the LED string.

Key features that simplify design and enhance performance include:

An internal 7.75V regulator that powers the IC from the high input voltage, eliminating the need for an auxiliary supply.

A programmable switching frequency (up to 300 kHz) set by a single external resistor, allowing designers to optimize for efficiency or component size.

A dimming control (LD) pin that accepts a low-frequency PWM signal for wide-range, flicker-free brightness control. This enables smooth dimming from 0% to 100% duty cycle.

Cycle-by-cycle current limiting and an open-loop protection feature, which provide robust safeguards for the circuit and the LEDs under fault conditions.

Designing with the HV9910CLG-G requires careful selection of external components. The inductor must be chosen to handle the peak switch current without saturating. The output capacitor smooths the current, and its value affects the current ripple through the LEDs. The forward voltage and maximum current of the LED string determine the necessary output voltage and the power rating of the external MOSFET and diode. Proper PCB layout is also critical to minimize switching noise and ensure stable operation.

In conclusion, the HV9910CLG-G offers a compelling blend of performance, integration, and protection features. Its ability to provide superior efficiency, accurate current control, and simple dimming interface makes it an excellent choice for designers creating high-performance LED lighting systems for industrial, commercial, and automotive applications.

ICGOODFIND: The Microchip HV9910CLG-G is a top-tier controller IC that effectively balances complexity and performance, making the design of robust and efficient switching LED drivers accessible for a broad spectrum of lighting products.

Keywords: LED Driver, Constant-Current Control, PWM Dimming, Switching Converter, HV9910