on semi 公司的ncp1654是電源功率因素控制器,與iec61000−3−2兼容,平均電流連續導通模式(ccm),具有快速瞬態響應特性和非常少的外接元件,起動電流低于75ua,關斷電流小于400ua,主要應用于平板電視,臺式計算機,ac適配器,白色家電和其它離線開關電源(smps).本文介紹了ncp1654的主要特性,功能方框圖, 軟起動方框圖, 300w 65khz功率因素修正電路以及ncp1654evb評估板主要特性,電路圖和所用材料清單.

ncp1654 power factor controller for compact and robust, continuous conduction mode pre-converters

the ncp1654 is a controller for continuous conduction mode (ccm) power factor correction step−up pre−converters. it controls the power switch conduction time (pwm) in a fixed frequency mode and in dependence on the instantaneous coil current.

housed in a so8 package, the circuit minimizes the number of external components and drastically simplifies the pfc implementation. it also integrates high safety protection features that make the ncp1654 a driver for robust and compact pfc stages like an effective input power runaway clamping circuitry.

ncp1654主要特性:

iec61000−3−2 compliant

average current continuous conduction mode

fast transient response

very few external components

very low startup currents (<75 ua)

very low shutdown currents (< 400ua)

low operating consumption

1.5 a totem pole gate drive

accurate fully integrated 65/133/200 khz oscillator

latching pwm for cycle−by−cycle duty−cycle control

internally trimmed internal reference

undervoltage lockout with hysteresis

soft−start for smoothly startup operation

shutdown function

pin to pin compatible with industry standard

this is a pb−free device

ncp1654安全特性:

inrush currents detection

overvoltage protection

undervoltage detection for open loop detection or shutdown

brown−out detection

soft−start

accurate overcurrent limitation

overpower limitation

ncp1654典型應用:

flat tvs, pc desktops

ac adapters

white goods, other off−line smps

圖1.ncp1654功能方框圖

圖2.ncp1654 ovp和快速瞬態響應特性

圖3.ncp1654軟起動方框圖

圖4.ncp1654應用電路:300w 65khz功率因素修正電路

ncp1654evb評估板

the ncp1654evb is a power factor controller to efficiently drive continuous conduction mode (ccm) step-up pre-converters. the ncp1654 allows operation in follower boost mode to drastically lower the pre-converter size and cost, in a straight-forward manner. the ncp1654 is a continuous conduction mode and fixed frequency controller (65khz). the coil (650 uh) is selected to limit the peak to peak current ripple in the range of 36 % at the sinusoid top, in full load and low line conditions.

ncp1654evb評估板主要特性:

fast transient response

low operating consumption

inrush currents detection

overvoltage protection

brown-out detection



圖5.ncp1654evb評估板外形圖

圖6.ncp1654evb評估板電路圖

ncp1654evb評估板材料清單: