Flyback controller features high integration

STMicroelectronics has introduced the HVLED101 90-400-V flyback controller for LED lighting applications up to 180 W. The integrated flyback controller offers enhanced performance and simplified design thanks to its integrated features, patented control techniques and support for primary-sensing regulation.

Joining ST’s HVLED family of high-power-factor controllers, the HVLED101 includes 800-V startup circuitry that cuts the LED turn-on time to less than 250 ms, said the company.

(Source: STMicroelectronics)

The device also integrates high-voltage input-sensing circuitry and a maximum power control (MPC) engine for consistent power output as the line voltage fluctuates. “This lets designers choose smaller and lower-cost external passive components to handle worst-case line conditions,” said ST, and “primary-sensing regulation without isolated feedback further reduces the bill of materials and enhances reliability.”

Patented features include ST’s input-current shaping algorithm that is said to lower total harmonic distortion (THD) and maximize the power factor. The HVLED101 is the first high-power-factor flyback controller to use ST’s new valley-locking technique to minimize audible noise, improve regulation and reduce distortion.

ST said current shaping and valley locking enhance the power factor and THD even at low and medium loads. Flyback converters controlled with the HVLED101 can achieve 5% THD at full load and 10% at 1/3 load to meet leading eco-design codes.

“Designers can program the delay time after zero-crossing detection in pure quasi-resonant operation using an external resistor,” said ST. “By ensuring gate turn-on at the lowest point of the valley, the HVLED101 minimizes energy losses and electromagnetic emissions (EMI).”

The HVLED101 enables converters to achieve maximum efficiency above 90% and no-load power below 100 mW, said the company.

Built-in protection features include overcurrent protection, input overvoltage protection and brownout protection. A smart auto-reload timer (ART) allows latch-free operation of all protection mechanisms to ensure high reliability.

The HVLED101 is in production in the narrow form-factor SO-14N package. It is priced from $0.99 for orders of 1,000 pieces. Two demonstration boards with the HVLED101 are available. The EVLHV101PSR50W is an 90-265 VAC, 60 V/0.8 A isolated flyback converter with primary-sensing regulation, while the EVLHV101SSR50W is a similar design with secondary-sensing regulation.