fairchild 公司的fsez1216是集成功率mosfet的初级边pwm控制器,能对低功率反激转换器增强性能.起动电流仅为10ua, 工作电流仅为3.5ma. fsez1216具有恒压(cv)和恒流(cc)控制而不需要次级反馈电路,固定的pwm屏障42khz,并具有跳频特性,以解决emi问题. fsez1216可用作手机,无绳电话,pda,数码相机的电池充电器,替代线性变压器和rcc smps.本文介绍了fsez1216 的主要特性, 功能方框图和典型应用框图以及5w(5v/1a)电源应用电路和所用材料清单(bom).
fsez1216 — primary-side-regulation pwm integrated power mosfet
this highly integrated pwm controller, fsez1216, provides several features to enhance the performance of low-power flyback converters. the proprietary topology of fsez1216 enables simplified circuit design for battery charger applications. a low-cost, smaller, and
lighter charger results when compared to a conventional design or a linear transformer. the startup current is only 10μa, which allows use of large startup resistance for further power saving.
to minimize the standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease pwm frequency under light-load conditions. this green-mode function assists the power supply in meeting power conservation requirements.
using fsez1216, a charger can be implemented with few external components and minimized cost. fsez1216 controller is available in an 8-pin dip package.
fsez1216 主要特性:
constant-voltage (cv) and constant-current (cc) control without secondary-feedback circuitry
green-mode function: pwm frequency linearly decreasing
fixed pwm frequency at 42khz with frequency hopping to solve emi problem
cable compensation in cv mode
low startup current: 10μa
low operating current: 3.5ma
peak-current-mode control in cv mode
cycle-by-cycle current limiting
vdd over-voltage protection with auto-restart
vdd under-voltage lockout (uvlo)
fixed over-temperature protection with latch
dip-8 package available
fsez1216 应用:
battery chargers for cellular phones, cordless phones, pda, digital cameras, power tools
replaces linear transformer and rcc smps
图1.fsez1216功能方框图
图2.fsez1216典型应用框图
图3.5w (5v/1a) 应用电路
5w (5v/1a)应用材料清单:
