Switcher IC ZVS flyback topology and advanced SR FET control enable 95% efficiency

Power Integrations has released the InnoSwitch5-Pro family of high-efficiency, programmable flyback switcher ICs. The single-chip switcher achieves over 95% efficiency with a novel secondary-side control scheme that attains ZVS without a dedicated and costly additional high-voltage switch. The new IC, which features a 750V or a 900V PowiGaN primary switch, primary-side controller, FluxLink isolated feedback and secondary controller with an I2C interface, optimises the design and manufacture of compact, highly efficient single- or multi-port USB PD adapters. Applications include notebooks, high-end cellphones and other portable consumer products, including designs that require the new USB PD EPR protocol.

Adnaan Lokhandwala, senior product marketing manager at Power Integrations, said: "The combination of ZVS and GaN is power supply magic. Switching losses vanish, and we can leverage the low conduction losses of GaN to implement super dense adapter layouts with far fewer components than asymmetric half-bridge circuits or active clamp alternatives. For example, we have demonstrated 140W/28V USB PD adapters in 4.2 cubic inches using only 106 components. The flyback topology used by InnoSwitch5-Pro ICs is much easier to implement than AHB and can also operate from universal mains with or without a PFC stage."

The flyback switcher ICs feature lossless input line voltage sensing on the secondary side for adaptive DCM/CCM and ZVS control to maximise efficiency and simplify design across line and load. The ICs also feature a post-production tolerance offset to facilitate accurate output constant-current control of over 2% to support the UFCS protocol. Excellent efficiency – better than 95% – enables designers to eradicate heat sinks, spreaders and potting materials for thermal management, further reducing size, weight, component cost and manufacturing complexity.

Key markets for this family of flyback switcher ICs include high-density USB PD 3.1 EPR, UFCS and multi-protocol adapters, notebook adapters and after-market single- and multi-port chargers and adapters.