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(wěn)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(yè)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
UCC28070 300W交叉PFC預穩(wěn)壓器參考設計
UCC28070 300-W Interleaved PFC Pre-Regulator Design Review
In higher power applications to utilize the full line power and reduce line current harmonics PFC Pre-regulators are generally required. In these high power applications interleaving PFC stages can reduce inductor volume and reduce input and output capacitor ripple current. This results in smaller overall magnetic volume and filter capacitor volume increasing the converters overall power density. This is made possible through distributing the power over two interleaved boost converters and the inductor ripple current cancellation that occurs with interleaving, reference [5]. This application note will review the design of a 300W two-phase interleaved power factor corrected (PFC) pre-regulator. This power converter achieves PFC with the use of the UCC28070 interleaved PFC controller, reference。
參考設計指標：
圖4。典型平均電流模式交叉PFC預穩(wěn)壓器電路圖
圖5。300W原型子板控制器電路圖
圖6。300W原型主板電源電路圖
參考文獻:[1].UCC28070 datasheethttp://www.dzsc.com/datasheet/UCC28070+_1137169.html.
[2].PFCdatasheethttp://www.dzsc.com/datasheet/PFC_1200255.html.
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