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LED driver uses peak current mode control scheme

Posted: 18 Mar 2011 ?? ?Print Version ?Bookmark and Share

Keywords:LED driver? LCD tv? transconductance?

Supertex Inc. has released the HV9860, a boost LED driver designed to optimize LED performance and extend LED life in RGB or white LED backlighting, LCD TVs and monitors, and LED lamps for general lighting. The IC uses a peak current mode control scheme and includes an internal transconductance amplifier to accurately control output current over all line and load conditions.

The HV9860 includes LED wiring fault detection, which protects an LED string from high current in cases of accidental short circuit from any tap in the string to ground. A wiring fault can happen during production when a wire connecting the LEDs gets shorted to the chassis, causing very high current delivered to the operating LEDs. The built-in protection provided by HV9860 identifies this scenario and shuts the IC down and signals a fault to the rest of the circuit.


HV9860: Single channel boost LED driver

The IC also provides a disconnect switch gate drive output, which can be used to achieve good PWM rise and fall times for the LED current using an external disconnect FET. The HV9860 has a DUTY pin which can be used to set the maximum duty cycle to either 90 percent (typ) or 75 percent (typ). The 75 percent duty cycle limit can be used for flyback applications. It also provides a TTL compatible, low-frequency PWM dimming input that can accept an external control signal with a duty ratio of 0-100 percent and a frequency of up to a few kilohertz.

The HV9860 is available in a 16-lead SOIC package (HV9860NG-G). The part is RoHS compliant. Samples are available now. Lead-time for production quantities is 4-6 weeks ARO. Pricing is US$0.95 each for the HV9860NG-G in 1K quantities.

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