HV9910 is designed to convert high voltage supplies (85V - 265VAC rectified) or (8V - 450VDC) to a constant current source for powering a string or a combination of strings of HB LEDs. HV9910 utilizes constant frequency peak current control pulse width modulation (PWM) operation using a small inductor and an external switch to minimize the LED driver losses.
Unlike conventional PWM controllers it uses a simple On/Off control to regulate the LED current, thus simplifying control circuit design. HV9910 features both linear and PWM dimming capability.
Static or dynamic dimming that governs LED brightness requires additional circuitry with existing solutions. HV9910 has built-in dimming controls that work with an external PWM signal featuring a dimming range of 0 to 100% or it can be set and adjusted linearly to any value between zero to maximum LED current by applying a control voltage to the linear dimming pin.
"HV9910 is the solution to meet customer needs for a low cost, simple HB LED driver for high voltage, off-line applications or low voltage, 12V to 45VDC battery-powered systems", states Brian Hedayati, Director of Marketing at Supertex. "With the introduction of HV9910, our recognized leadership in the off-line LED driver IC market will be further strengthened, as we continue to work with LED suppliers in developing reference designs for their recommended applications."
LEDs are far more reliable and long lasting when driven by a constant current than by a voltage source. Some existing methods use standard off-line power supplies to generate a lower output DC voltage such as using resistors in series or using secondary regulators in series with the LEDs to maintain a constant current. The first method is inefficient and generates excessive heat that has to be removed, while the second can be costly.
HV9910 converts the high voltage source directly to a constant current source to power the LEDs efficiently and cost effectively. HV9910 can efficiently power multiple LED strings. Typical efficiencies of 91-94% at power levels of 40-60W in off-line applications can be easily obtained.
HV9910 is available in a SO-16-pin, SO-8-pin and DIP-8-pin packages. Samples are available from stock. Lead-time for production quantities is 6 weeks ARO. Pricing is US$0.76 (SO-16-pin package), $0.62 (SO-8-pin package) and $0.60 (DIP-8-pin package) each in 5K quantities.