NXP公司的TEA1721FT是小型低成本开关电源(SMPS)控制器,直接从通用火线电压整流输入,适用于5W以下的应用.器件集成了高压(700V)功率开关,无负载功耗小于30mW,具有过压保护(OVP),欠压锁住(UVLO),超温保护(OTP),主要用于5W手机电池充电器,TV和台式PC的待机电源,白色家电电源.本文介绍了TEA1721主要特性和优势,方框图,5 W GreenChip演示板特性,电路图,材料清单和PCB布局图.
The TEA1721 is a small and low cost module Switched Mode Power Supply (SMPS) controller IC for low power applications (up to 5 W) and operates directly from the rectified universal mains input. The device includes a high voltage power switch (700 V) and has been optimized for flyback converter topologies to provide high-efficiency over the entire load range with ultra-low power consumption in the no-load condition. It provides a circuit for start-up directly from the rectified mains voltage without any external bleeder circuits.
The converter operates as a regulated voltage source from no-load up to the maximum output current and operates as current source that delivers the maximum current over a broad output voltage range. Using the TEA1721, a low power converter can be built at minimum cost and with the minimum number of external components.
The controller regulates the output voltage with primary-side sensing which eliminates the need for an additional secondary feedback circuitry and simplifies the design. At higher power levels, a frequency and current control mode is used. It operates with Burst mode control at low power levels and no-load condition. The burst mode minimizes audible noise and provides an energy saver state which reduces the power consumption in no-load condition. The Burst mode frequency of 1750 Hz enables no-load power consumption below < 30 mW at high mains input.

TEA1721主要特性和优势:

电源特性:
 Low power SMPS controller with integrated power switch designed for applications up to 5 W
 700 V high voltage power switch for global mains operation
 Primary sensing for control of the output voltage without optocoupler and secondary feedback circuitry
 Minimizes audible noise in all operation modes
 USB battery charging and Energy Star 2.0 compliant
 Jitter function for reduced EMI

绿色特性:
 Enables no-load power consumption < 30 mW
 Very low supply current in no-load condition with energy saver mode
 Incorporates a high voltage start-up circuit with zero current consumption under normal switching operation
 Available in halogen-free and Restriction of Hazardous Substances (RoHS) SO7 Package

保护功能:
 OverVoltage Protection (OVP) on Feedback control (FB) pin with auto-restart
 UnderVoltage LockOut (UVLO) protection on IC supply pin
 OverTemperature Protection (OTP)
 Soft-start by reduced peak current for zero and low output voltage
 Demagnetization protection for guaranteed discontinuous conduction mode operation
 Open and short-circuit protection of the Feedback control (FB) pin
 Short-circuit protection of the charger output

TEA1721应用:
 Battery chargers for cellular phones and other low power adapters up to 5 W
 Standby supply for TV and desktop PC
 Power supply for White Goods applications

图1.TEA1721方框图

TEA1721FT 5 W GreenChip SP小型演示板
This user manual describes a 5 W Constant Voltage (CV) or Constant Current (CC) universal input power supply for mobile phone adapters and chargers. This demo board is based on the GreenChip SP TEA1721FT.
GreenChip SP TEA1721FT enables only 5 % output voltage tolerance at dynamic load behavior with low no-load power dissipation <40 mW. The TEA1721FT design ensures a low external component count for cost-effective applications. In addition, the TEA1721FT provides advanced control modes for optimal performance. The TEA1721FT integrates the 700 V power MOSFET switch and SMPS controller.

5 W GreenChip演示板特性:
• Has only 5 % output voltage tolerance at dynamic load behavior
• Enables low no-load power dissipation <40 mW
• Low component count for a cost-effective design
• Advanced control modes for optimal performance
• SMPS controller with integrated power MOSFET switch
• 700 V high-voltage power switch for global mains operation
• Primary sensing at end-of-conduction for accurate output voltage control
• Avoids audible noise in all operation modes
• Compensation of cable impedance included
• Jitter function for reduced EMI
• USB battery charging and Energy Star compliant
• Universal mains input
• Isolated output
• Highly efficient: >77 %
• OverTemperature Protection (OTP)

5 W GreenChip演示板输入和输出指标:


图2.5 W GreenChip演示板外形图(正面)

图3.5 W GreenChip演示板外形图(背面)

图4.TEA1721FT 5 W GreenChip演示板电路图

TEA1721FT 5 W GreenChip演示板材料清单:



图5.TEA1721FT 5 W GreenChip演示板PCB布局图

图6.TEA1721FT 5 W GreenChip演示板变压器电路图
变压器电指标: