FA5590 FUJI [Fuji Electric], FA5590 Datasheet - Page 12

• Manufacturer Part Number: FA5590
• Description: FUJI Power Supply Control IC
• Manufacturer: FUJI [Fuji Electric]

AN-016E Rev.1.2
April-2011
I
I
L1
current flowing through the inductor repeats in
triangular waveforms. The mean value (IL 1(mean))
of the triangular wave current becomes 1/2 of the
peak value (IL 1(peak)). (Fig. 3)
the inductor current to sine wave and removing
switching ripple current, the smoothed current
flowing from the AC input power source has sine
wave shape.
in
(2) Power-factor correction operation
As explained in the switching operation, the
By controlling to make outline linking the peak of
I
L1
Fig.3 Outline of inductor and AC input current
Fuji Electric Co., Ltd.
拡大
enlarged
C1でスイッチングに
filtered the high
frequency content
by C1
I
I
=1/2×I
伴うリップル
L1(peak)
L1(mean)
電流を除去
2×I
L1(peak)
in(peak)
I
in(peak)
FA5590N,FA5591N
error amplifier
エラーアンプ
to zero, Power MOS turns on and saw
input voltage
when the inductor current goes down
MOSFET
インダクタ電流
出力
Gate
output
inductor
入力電圧
current
tooth wave starts to rise
shown in Fig. 4.
of IC (gate drive signal for Power Mos) with
combination of the error amplifier output and saw
tooth wave. While the load is constant, the output
of the error amplifier is constant, and on time also
stays constant.
Since an inclination of inductor current depends on
input voltage (an inclination of inductor current is
proportional to input voltage) and on time is
constant, the outline linking the peak of the inductor
current becomes same AC waveform as the input
voltage, which enables power-factor correction
operation.
Power Mosがオンし、のこぎり波が
12
インダクタ電流ゼロのタイミングで
FA5590/FA5591 uses fixed on time control
This control determines the on time of the output
立ち上がる(臨界動作)
Fig.4 Fixed on time control
Outline linking the peak
インダクタ電流
of the inductor current
http://www.fujielectric.co.jp/products/semiconductor/
ピーク
Outline linking the peak of the inductor
current has the same waveform of the
input voltage
(Power factor correction operation)
(負荷一定)の場合、オン幅が
一定となる(オン幅固定制御)
constant, on time stays constant
エラーアンプの出力が一定
amplifier is constant and load is
入力電流のピークが入力
電圧と同じAC波形となる
While the output of the error
(Fixed on time control)
(力率改善動作)
インダクタ電流
average waveform of
the inductor current
平均