The NCP4307 is high performance driver for use with synchronous rectification (SR) MOSFETs

The NCP4307 is high performance driver for use with synchronous rectification (SR) MOSFETs in multiple high performance switch mode power supplies topologies. The device will self-supply from an internal 200V CS pin, enabling high side configuration and low VOUT without requiring an auxiliary supply. The dual VCC pin selects the optimal VCC source to minimize losses, thereby optimizing designs for wide range VOUT applications.

Secondary Side Synchronous Rectification Driver for High Efficiency SMPS Topologies

The NCP4307 is high performance driver tailored to control a synchronous rectification mosfet in switch mode power supplies.

Thanks to its high performance drivers and versatility, it can be used in various topologies such as DCM or CCM flyback, quasi resonant flyback and forward.

Internal minimum off−time and on−time blanking periods help to fight the ringing induced by the PCB layout and other parasitic elements. A reliable and noise less operation of the SR system is ensured due to the Self Synchronization feature. The NCP4307 also utilizes Kelvin connection of the driver to the mosfet to achieve high efficiency operation at full load and utilizes a light load detection architecture to achieve high efficiency at light load.

The precise turn−off threshold, extremely low turn−off delay time and high sink current capability of the driver allow the maximum synchronous rectification MOSFET conduction time and enables maximum SMPS efficiency.

Self−supply capability allows to use NCP4307 in high side configuration and/or in low output voltage SMPS without auxiliary winding or other power source.

NCP4307 Features:

• Self−Contained Control of Synchronous Rectifier in CCM, DCM and QR for Flyback Applications

• Precise True Secondary Zero Current Detection

• Typically 15 ns Turn off Delay from Current Sense Input to Driver

• Rugged Current Sense Pin (up to 200 V)

• Self−Supply Capability in Case of High Side Operation or Low VOUT

• Ultrafast Turn−off Trigger Interface/Disable Input (10.5 ns)

• Internal Minimum ON−Time With Reverse Current Protection

• Internal Minimum OFF−Time with Ringing Detection

• Improved Robust Self Synchronization Capability

• 7 A / 2 A Peak Current Sink / Source Drive Capability

• Operating voltage Range up to VCC = 35 V

• Automatic Light−Load Disable Mode

• High Side Operation Capability without External Components or Auxiliary Winding

• Two VCC Pins Option Allows to Optimize Power Consumption in Wide VOUT Range Applications

• Low Startup and Disable Current Consumption

• TSOP6 Package

• These are Pb−Free Devices


• Notebook Adapters

• High Power Density AC/DC Power Supplies (Cell Phone Chargers)


• All SMPS with High Efficiency Requirements

This evaluation board users manual describes a 65 W, Type C interface PD3.0, universal AC input, constant voltage power supply intended for smart phone, PAD and NB adaptor supporting PD3.0 or PPS protocol, where isolation from the AC mains is required, and low cost, high efficiency, and low standby power are essential.

The featured power supply is a simple QR flyback topology utilizing onsemis NCP1345 HF PWM controller, NCP4307 synchronous rectified controller, FDMS86180 synchronous MOSFET and NTTFS4C02 Switch MOSFET.

This Design Note provides the complete circuit schematic details, PCB and BOM for 65 W Type C Interface PD3.0 Power adapter solution which supports PD output (5 V / 3 A, 9 V / 3 A, 12 V / 3 A, 15 V / 3 A, 20 V / 3.25 A).

This design combined with onsemis FUSB15101 PD3.0 protocol controller to provide PD3.0 and PPS functions.

This design also proposes a dual auxiliary power supply to supply PWM controller, the PWM controller is supplied by high voltage auxiliary voltage at low output voltage and

supplied by low voltage auxiliary voltage at high output voltage.

NCP1345 is next generation of NCP1342 HF QR controller, it provides precise primary CC also precise primary OVP protection, built in external dual Vcc circuit, improved jittering function which eliminated large output ripple also adaptive gate drive to reduce secondary voltage stress.

This design also uses NCP4307 synchronous rectified controller which eliminated external Vcc circuit at low output, also placed on high side or low side.