• Integrated 700V GaN FET
• Programmable Gate Driver Current
• DCM+QR Combined Operating Mode
• Switching Frequency Range: 25kHz–500kHz
• VCCH up to 140V Power Supply
• Automatic Valley Lockout from 1 to 6 Cycles
• Accuracy Output OCP Protection
• Adaptive OCP (LPS, Limited Power Source)
• Low Frequency Burst (1kHz)
• Frequency Modulation to Reduce EMI Noise
• Internal Soft-Start  Integrated 700V HV Startup
• X-cap Discharge Protection
• Brown-In/Out Protections
• Programmable Output OVP and UVP
• Current Sense Resistor Short Protection
• Internal and External OTP
• New Package for Excellent Heat Sink
• Compact Package: QFN5*7-18

The SY50296/8A is a high frequency quasi-resonant (QR) flyback converter designed for Power Delivery (PD) adaptors and quick chargers. It integrated GaN FET in a small package and suitable for wide output voltage range applications. Switching frequency can be 25kHz–500kHz and transformer size can be smaller.

The SY50296/8A operates using peak current control. It provides a QR mode in which the GAN FET can be turned on at a valley point to reduce switching loss, especially under high input voltages.

In conventional QR flyback solutions, the valley number always varies between 1 and 2 or 3 and 5, which increases VO ripple and creates audible noise. The SY50296/8A uses a proprietary circuit to lock the valley number between 1 and 6, for improved stability compared with other conventional QR solutions.

If load decreases, SY50296/8A will enter discontinuous conduction mode (DCM) to reduce the switching frequency for higher efficiency. If the load is very light, the SY50296/8A will enter burst mode to reduce power loss.

The SY50296/8A provides comprehensive functions to ensure reliable operation, including: HV startup, X-cap discharge, brown-out protection, output and VCC overvoltage protection (OVP), output undervoltage protection (UVP), internal over temperature protection (OTP), and open-loop protection (OLP).

It is recommended to use SY5239 as secondary side Synchronous Rectifier (SR) controller and Zero Voltage Switching (ZVS) can be achieved for higher efficiency.

The SY50296/8A is available in a QFN5*7-18 package.