Resonant power converter/PFC chipset reduces component count


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 is also where the APEC 2022 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 booth. Integrations, where I met Doug Bailey, Vice President of Marketing at PI. He introduced me to the company’s latest family of highly integrated resonant power conversion and power factor correction (PFC) ICs.

These devices are intended to simplify the development of compact and super efficient power adapters; open frame power supplies for televisions; monitors with USB PD ports; all-in-one PC; game consoles; and battery chargers for power tools and electric bicycles.

These devices reflect the company’s long-standing commitment to creating electronic components that make it easier and more economical for manufacturers to create environmentally friendly products that meet, and often exceed, global efficiency standards set. place to fight climate change.

Green to the Bone

Power supply designs based on the new HiperLCS-2 chipset can provide continuously regulated output that meets the world’s toughest no-load and standby efficiency regulations. Both primary and secondary controllers operate at over 95% efficiency over nearly their entire load range. They also draw less than 50 mW under no-load conditions at 400 Vdc input.

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

Likewise, PI’s complementary family of PFC HiperPFS-5 ICs enables designers to address the growing number of markets that require even smaller electronic products to have PFC capabilities.

Powerful Building Blocks

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

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

The secondary-side controller uses the company’s proprietary FluxLink safety-isolated high-speed digital feedback control to synchronize switching. It enables power supplies based on the HiperLCS-2 chipset to achieve sub-1% regulation accuracy over the full line and load range and over all output variations. Additionally, it offers much faster transient response and greater long-term reliability than optocouplers.

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

PFC without tears

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

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

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

At light loads, a built-in power factor enhancement (PFE) function compensates the input filter capacitance, maintaining a high PF of 0.96, even at 20% load. No-load power consumption is only 38 mW.

HiperPFS-5 ICs are designed to operate reliably even in locations where mains power can be very unstable, often leading to overvoltage failures in conventional converters. As a result, they maintain a high power factor up to 305 V ac and can operate continuously up to 460 V ac during line surges. The controller’s low-profile InSOP-T28F SMD power supply includes exposed cooling pads that stay at source potential, providing efficient cooling and simplifying the EMI solution.

Pricing and development resources

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

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

Read more articles from our APEC 2022 coverage.

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