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Supporting QR Mode Operation with HV start, embedded high-reliability Gate Driver for GaN FET

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The DIODES™ AP33510 is a highly integrated, quasi-resonant, flyback, GaN FET controller specially designed for offline flyback power supplies that require low standby power, high-power density, and comprehensive protection.

The controller operates in QR mode at full load. This makes switching events always occur in the drain-source valley, minimizing switching loss. The maximum switching frequency is internally limited to 150kHz. To ensure stable valley switching and prevent transformer audible noise caused by frequency hopping, the AP33510 features a proprietary valley-lockout technique inside.

When load decreases from full load, the IC will enter into PFM mode with frequency foldback for higher power conversion efficiency. At no load or light load, the controller will enter burst mode to minimize  power consumption, and the minimum switching frequency (about 25kHz) is set to avoid any audible noise.

Piecewise linear line compensation ensures constant output power limit over an entire line voltage range.

To ensure converter ruggedness, the AP33510 implements comprehensive protective features such as brown-in/out detection, cycle-by-cycle current limiting, output OVP/UVP, overload protection, and overtemperature protection.


  • Up to 150kHz Quasi-Resonant Operation Mode for High Output Voltage
  • Frequency Foldback for High Average Efficiency
  • High Reliability Gate Driver for GaN FET
  • Built-in High-Voltage Startup
  • Soft Start During Startup Process
  • Integrated X2 Capacitor Discharge Function
  • Adaptive Output Power Limit with Output Voltage
  • Non-Audible-Noise Green-Mode Control
  • Wide VCC Power Supplied with 120V LDO
  • Internal Slope Compensation
  • Frequency Dithering for Reducing EMI
  • VCC Maintain Mode
  • Comprehensive System Protection Features:
    • Secondary Winding Short Protection
    • VCC Overvoltage Protection (VOVP)
    • Line Overvoltage Protection (LOVP)
    • Overload Protection (OLP)
    • Cycle-by-Cycle Over-Current Protection
    • Pin-Fault Protection
    • Brown In/Out Protection (BNI/BNO)
    • Secondary Side OVP (SOVP) and UVP (SUVP)
    • Internal OTP
  • Packaged in the SSOP-9 (Type CJ)
  • Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
  • Halogen and Antimony Free. “Green” Device (Note 3)
  • For automotive applications requiring specific change control (i.e. parts qualified to AEC-Q100/101/104/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative.



  • General GaN FET drivers
  • Programmable switching AC/DC adapters or quick chargers
  • High-density industrial and consumer power supplies

Product Specifications

Product Parameters

Operation Mode QR
HV Start-UpCircuit Yes
Vcc_MAX(V) 150 (VCC_IN)
UVLOThresholdon/off (V) 18/6.7 V
Gate OutputCurrent (mA) -0.7 mA
Maximum OscillationFrequency (kHz) 150(QR mode) kHz
BNO Auto-Recover
LOVP Auto-Recover
Release Date 202207

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Orderable Part Number Buy from Distributor / Contact Sales Request Samples


Authorized Distributor Quantity Inventory Date Countries/Regions Buy Online
Digi-Key Electronics 3975 11/30/2022 Europe, Asia, North America Buy Now
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