基于NCP4303设计的高效开关电源技术

本文介绍了NCP4303主要特性，方框图，ZCD检测电路框图以及LLC转换器，DCM或QR反激转换器与在宽频LLC应用的电路。
NCP4303是On Semi 公司的次级同步整流驱动器，是高效开关电源（SMPS）解决方案。NCP4303具有阈值可调的精密的次级零电流检测，工作模式包括CCM，DCM和QR反激拓扑。工作电压高达30V，具有5A/2.5A峰值沉/源驱动能力，典型应用包括笔记本电脑适配器，大功率密度的AC/DC电源，游戏机和所有高效开关电源。

NCP4303主要特性：

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

Precise True Secondary Zero Current Detection with Adjustable Threshold

Automatic Parasitic Inductance Compensation Input

Typically 40 ns Turn off Delay from Current Sense Input to Driver

Zero Current Detection Pin Capability up to 200 V

Ultrafast Trigger Interface to External Signal for CCM operation

Disable Input to Enter Standby or Low Consumption Mode

Adjustable Minimum On Time Independent of VCC Level

Adjustable Minimum Off Time Independent of VCC Level

5 A / 2.5 A Peak Current Sink / Source Drive Capability

Operating Voltage Range up to 30 V

Gate Drive Clamp of Either 12 V (NCP4303A) or 6 V (NCP4303B)

Low Startup and Standby Current Consumption

Maximum Frequency of Operation up to 500 kHz

SOIC−8 Package

These are Pb−Free Devices

NCP4303典型应用：

Notebook Adapters

High Power Density AC/DC Power Supplies

Gaming Consoles

All SMPS with High Efficiency Requirements

图1。NCP4303方框图

图2。NCP4303 ZCD检测电路框图

图3。NCP4303典型应用案例：LLC转换器

图4。NCP4303典型应用案例：DCM或QR反激转换器

图5。NCP4303在CCM反激转换器的应用电路图

图6。NCP4303在宽频LLC应用的电路图