Description

The AP3128 is a peak-current control, multi-mode (QR+CCM) PWM controller optimized for high performance, low standby power and cost-effective offline flyback converters. At no load or light load, the IC will enter burst mode to minimize standby power consumption. The minimum switching frequency is set to avoid audible noise. When the load increases, the IC will enter QR mode with frequency foldback to improve system efficiency and EMI performance. The maximum switching frequency about 105kHz is set to clamp the QR frequency to reduce switching power loss. Furthermore, the frequency dithering function is built in to reduce EMI emission. Internal piecewise linear line compensation ensures constant output power limit over the entire universal line voltage range. Comprehensive protection features are included, such as brown-out protection, cycle-by-cycle current limit (OCP), VCC Overvoltage Protection (VOVP), Secondary-side Output OVP (SOVP) and UVP (SUVP), internal OTP, Overload Protection (OLP), and pins’ fault protection.

Feature(s)

Multi-Mode Control
Quasi-Resonant (QR) Operation at High Line Voltage
Continuous Current Mode (CCM) Operation at Low Line Voltage
Non-Audible-Noise Quasi-Resonant Control
Soft Start During Startup Process
Frequency Fold Back for High Average Efficiency
Constant Over Current Protection
Secondary Winding Short Protection with FOCP
Frequency Dithering for Reducing EMI
Useful Pin Fault Protection:
- SENSE Pin Floating
- FB/Opto-Coupler Open/Short
Comprehensive System Protection Feature:
- V_CC Overvoltage Protection (VOVP)
- Overload Protection (OLP)
Brown Out Protection (BNO)
Secondary Side OVP (SOVP) and UVP (SUVP)
Totally Lead-Free & Fully RoHS Compliant
Halogen and Antimony Free. “Green” Device
For automotive applications requiring specific change control (i.e. parts qualified to AEC-Q100/101/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative. https://www.diodes.com/quality/product-definitions/

Specifications & Technical Documents

Product Parameters

Operation Mode	QR/CCM
HV Start-UpCircuit	Yes
Vcc_MAX(V)	60
UVLOThresholdon/off (V)	15.8/6.5 V
Gate OutputCurrent (mA)	-0.375 mA
Maximum OscillationFrequency (kHz)	80 (CCM mode)/105 (QR mode) kHz
BNO	Auto-Recover
LOVP	N/A
Release Date	202109

Technical Documents

Recommended Soldering Techniques

TN1.pdf

RoHS CofC

RoHSFile

Purchase & Availability

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN #	Issue Date	Implementation Date	Subject
PCN-2770	2025-10-30	2025-10-30	Add Fab Site Code, Country of Diffusion (COD) and Assembly Site Origin (ASO) on Product and Shipping Labels for all Diodes Products

AP3128