TI UCC28740 36W高效适配器参考设计

TI公司的UCC28740是绝缘-反激电源控制器,采用光耦器来提高大负载的瞬态响应,恒流(CC)稳压通过初级边稳压(PSR)来实现.电流稳定度±5%,电压稳定度±1%,器件集成了700V起动开关,动态控制工作状态,支持超低待机功耗,主要用在AC/DC电源,电动自行车,服务器PSU,低端洗衣机,烘干机,微波炉,太阳能逆变器等.本文介绍了UCC28740主要特性,框图, 设计案例以及85 - 265VAC输入12V@3A 36W高效适配器参考设计主要特性,电路图和材料清单.
The UCC28740 isolated-flyback power-supply controller provides Constant-Voltage (CV) using an optical coupler to improve transient response to large-load steps. Constant-Current (CC) regulation is accomplished through Primary-side Regulation (PSR) techniques. This device processes information from opto-coupled feedback and an auxiliary flyback winding for precise high-performance control of output voltage and current.
An internal 700-V startup switch, dynamically-controlled operating states, and a tailored modulation profile support ultra-low standby power without sacrificing startup time or output transient response.
Control algorithms in the UCC28740 allow operating efficiencies to meet or exceed applicable standards. The drive output interfaces to a MOSFET power switch. Discontinuous conduction mode (DCM) with valley-switching reduces switching losses. Modulation of switching frequency and primary current-peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.
The controller has a maximum switching frequency of 100 kHz and always maintains control of the peak-primary current in the transformer. Protection features keep primary and secondary component stresses in check. A minimum switching frequency of 170 Hz facilitates the achievement of less than 10-mW no-load power.
UCC28740主要特性:
Less than 10-mW No-Load Power Capability
Opto-Coupled Feedback for CV, and Primary-Side
Regulation (PSR) for CC
Enables ±1% Voltage Regulation and ±5% Current
Regulation Across Line and Load
700-V Startup Switch
...