本文介紹了UCC28070 主要特性，簡化方框圖和功能方框圖，以及采用兩個UCC28070的四相輸出應用框圖，300W交叉PFC預穩壓器參考設計主要指標，控制器電路圖和電源電路圖。

UCC28070是先進的功率因素修正器件，集成了兩個工作在180度反相的PWM。 這種PWM交叉工作能降低輸入和輸出紋波電流，使得導電EMI濾波變得更加容易，成本更低。可編程工作頻率從30 kHz 到300 kHz，有極好的效率和多種保護功能，主要用在高效服務器和臺式PC電源，通信整流器，白色家電和工業設備。

UCC28070 主要特性：

Interleaved Average Current-Mode PWM Control

with Inherent Current Matching

Advanced Current Synthesizer Current Sensing for

Superior Efficiency

Highly-Linear Multiplier Output with Internal Quantized

Voltage Feed-Forward Correction for Near-Unity PF

Programmable Frequency (30 kHz to 300 kHz)

Programmable Maximum Duty-Cycle Clamp

Programmable Frequency Dithering Rate and Magnitude

for Enhanced EMI Reduction

Magnitude: 3 kHz to 30 kHz

Rate: Up to 30 kHz

External Clock Synchronization Capability

Enhanced Load and Line Transient Response through Voltage

Amplifier Output Slew-Rate Correction

Programmable Peak Current Limiting

Bias-Supply UVLO, Over-Voltage Protection, Open-Loop Detection,

and PFC-Enable Monitoring

External PFC-Disable Interface

Open-Circuit Protection on VSENSE and VINAC pins

Programmable Soft Start

20-Lead TSSOP/SOIC Packages

UCC28070 應用：

High-Efficiency Server and Desktop Power Supplies

Telecom Rectifiers

White Goods and Industrial Equipment

圖1。UCC28070簡化方框圖

圖2。UCC28070功能方框圖

圖3。采用兩個UCC28070的四相輸出應用框圖