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Resonant Power-Converter/PFC Chipset Slashes Component Count

April 4, 2022
Power Integrations’ new resonant power converter and PFC ICs contain several unique architectural features that boost efficiency and reliability.

This article is part of our APEC 2022 coverage. 

Greetings from Houston, Texas, the oil-rich city of paradox where the art car movement was born. Houston also is where the 2022 APEC power technology conference was held in-person for the first time since 2019. Excitement and innovation were in abundance at the show, including at the Power Integrations booth, where I met with Doug Bailey, PI's VP Marketing. He introduced me to the company’s latest family of highly integrated resonant power-converter and power-factor-correction (PFC) ICs.

These devices are intended to simplify the development of compact, super-efficient, power adapters; open-frame power supplies for TVs; monitors with USB PD ports; all-in-one PCs; game consoles; and battery chargers for power tools and e-bikes.

These devices reflect the company’s longtime commitment to creating electronic components that make it easier and more economical for manufacturers to create eco-friendly products meeting, and often exceeding, global efficiency standards being put in place to combat climate change.

Green to the Bone

Power-supply designs based on the new HiperLCS-2 chipset can provide a continuously regulated output that complies with the world's most stringent no-load and standby efficiency regulations. Both the primary and secondary controllers operate above 95% efficiency across nearly their entire load range. They also draw less than 50 mW under no-load conditions at 400-V dc input.

Resulting heat dissipation is low enough to permit direct heat dissipation through the circuit's FR4 PCB material. Thus, it eliminates the need for heatsinks in adapter designs up to 220 W (continuous output with up to 170% peak power capability).

Similarly, PI's HiperPFS-5 companion family of PFC ICs enables designers to address the growing number of markets that require even lower-power electronic products to have PFC capabilities.

Powerful Building Blocks

Power Integrations created the HiperLCS-2 chipset family to simplify the design and reduce the cost of high-efficiency LLC resonant power-converter solutions from 80 to 270 W. Complementing the new switcher series is the HiperPFS-5 family, a series of high-efficiency quasi-resonant PFC ICs that feature an integrated 750-V gallium-nitride (GaN) switch. Together, they form the building blocks for PFC power supplies, capable of delivering up to 200+ W at over 95% efficiency across virtually their entire load range.

The dual-chip solution features an isolation device with a high-bandwidth LLC controller, a synchronous rectification driver, and a separate half-bridge power device utilizing PI’s unique 600-V FREDFETs with lossless current sensing and high- and low-side drivers.

The secondary-side controller uses the company’s exclusive FluxLink safety-isolated high-speed digital feedback control to synchronize switching. It allows supplies based on the HiperLCS-2 chipset to achieve regulation accuracy of under 1% across line and load range and across production variations. In addition, it provides much faster transient response and greater long-term reliability than optocouplers.

All HiperLCS-2 family members feature self-powered startup and provide the startup bias for an optional PFC stage. Secondary-side sensing provides less than 1% regulation accuracy across line and load range and across production variations. The use of FluxLink technology for safety-isolated, high-speed digital feedback control provides much faster transient response and better long-term reliability than optocoupler-based isolation circuits.

PFC Without Tears

Featuring an integrated 750-V GaN switch based on PI's PowiGaN technology, the HiperPFS-5 family of PFC ICs can deliver up to 240 W without a heatsink at efficiencies of up to 98.3% while achieving a power factor of better than 0.98. The highly integrated ICs, based on a quasi-resonant (QR), variable-frequency discontinuous-conduction-mode (DCM) boost PFC topology, require only a small number of external passives to implement compact, efficient power-factor stages.

The PFC controller can be seamlessly paired with the new HiperLCS-2 power-converter chipset for use in many electronic appliances like those mentioned earlier. It can also be used with the company's InnoSwitch4-CZ active-clamp flyback ICs.

HiperPFS-5 PFCs’ DCM control technique adjusts the switching frequency across its output load, input line voltage, and input line cycle. QR DCM control ensures low switching losses and permits the use of a low-cost boost diode. Thanks to the variable-frequency engine, boost inductor size can be reduced by more than 50% compared to conventional critical-conduction-mode (CRM) boost PFC circuits.

At light loads, an integrated power-factor-enhancement (PFE) feature compensates for input filter capacitance, maintaining a high PF of 0.96, even at 20% load. No-load power consumption is just 38 mW.

The HiperPFS-5 ICs are designed to operate reliably even in locations where the mains power can be highly unstable, which often leads to overvoltage failures in conventional converters. As a result, they maintain a high power factor up to 305 V ac and can operate continuously at up to 460 V ac during line swells. The controller's low-profile, InSOP-T28F SMD power package features exposed cooling pads that remain at source potential, providing effective cooling and simplifying the EMI solution.

Pricing and Development Resources

Both devices in the HiperLCS-2 chipset are housed in low-profile InSOP-24 packages. Pricing starts at $3.20 per chipset in 10,000-unit quantities. HiperPFS-5 QR PFC controller devices are priced at $2.34 in 10,000-unit quantities.

Designers wishing to evaluate the HiperLCS-2 LLC resonant power converter ICs and the HiperPFS-5 quasi-resonant PFC controller ICs may download reference design DER-672.

Read more articles from our APEC 2022 coverage. 

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