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Power Integrations

Power Integrations InnoSwitch4-CZ Flyback Switcher ICs

In conjunction with PI’s ClampZero™ Solution

The Power Integrations InnoSwitch4-CA is a family of Flyback Switcher ICs, marking a significant milestone for GaN technology.

Made for extremely compact chargers in applications such as phones, tablets and laptops, the InnoSwitch4-CZ family incorporates a 750 V switch using Power Integrations’ PowiGaN™ technology to enable 95% flyback efficiency.

The Power Integrations InnoSwitch4-CZ group also includes primary and secondary controllers, active clamp drive, synchronous rectification and safety-rated feedback in a single, compact InSOP-24D package. A switching frequency of up to 140 kHz minimizes transformer size, further increasing power density, while the ClampZero active clamp device increases system efficiency up to 95%.

The new flyback switcher ICs enable exceptional CV/CC accuracy, independent of external components and consume less than 30 mW no-load, including line-sensing safety and protection features. The devices are fully protected featuring auto-restart or latching fault response for output over-voltage and under-voltage protection, multiple output under-voltage fault thresholds and latching or hysteretic primary over-temperature protection.

InnoSwitch4-CZ Schematic

Off-Line CV/CC ZVS Flyback Integrated Switcher IC with 750 V PowiGaN, Active Clamp Drive and Synchronous Rectification, Pairs With ClampZero Active Clamp IC

Power Integrations – InnoSwitch4-CZ Schematic

ClampZero Schematic

Active Clamp IC with Integrated High-Voltage Switch, Pairs with InnoSwitch4 Family of Offline Switcher ICs

Power Integrations – ClampZero Schematic

Key Features (InnoSwitch4-CZ)

  • Up to 95% efficiency
  • Robust 750 V PowiGaN primary switch
  • Less than 30 mW no-load consumption including line sense
  • Steady-state switching frequency up to 140 kHz minimizes transformer size
  • Exceptional CV/CC accuracy, independent of external components
  • PI’s integrated FluxLinkTM isolated feedback link
  • Robust, comprehensive protection and safety features
  • InSOP-24D package


  • USB PD adapters
  • Phones
  • Tablets
  • Laptops

Design Tool:

  • PI Expert with InnoSwitch4-CZ

Design Examples:

  • DER-928 ultra-compact, no-heatsink, 60 W USB PD adapter