AMC3842B 데이터 시트보기 (PDF) - ADDtek Corp

부품명

상세내역

제조사

AMC3842B

CURRENT MODE PWM CONTROLLER

ADDtek Corp 

AMC3842B/43B/44B/45B

APPLICATION INFORMATION

Error

Amp

Rf

RS

COMP

ISENSE

Cf GND

2R

R

1V

Current

Sense

Comparator

Fig. 1. Current Sense Circuit

Peak current (IS) is set by: IS(MAX) = 1V/RS

2.5V

Error

Amp

0.5mA

Zi

VFB

Zf COMP

VREF

RT

RT/CT

CT

GND

Fig. 2. Error Amplifier Configuration - the

amplifier can source or sink up to 0.5mA

Fig. 3. Oscillator Section

1.72

For RT < 5K, f = RTCT

VREF

RT

4.7K

1K

Error AMP

Adjust

4.7K

2N2222

100K

5K

ISENSE

Adjust

COMP VREF

VFB

VCC

ISENSE Output

RT/CT GND

0.1µF

1K,

1W

0.1µF

VCC

Output

GND

Fig.

4. Open-loop laboratory

associated with capacitive

test fixture:

loads. Timing

aCnadrebfyupClagTsrsocuanpdaincigtoterschshnoiquuldesbaereconnenceecstseadrytofoGr NhiDghppineaink

currents

a single

point ground. The transistor and 5K potentiometer are used to sample the oscillator waveform and apply an

adjustable ramp to the ISENSE pin

Copyright © 2006 ADDtek Corp.

7

DD019_F -- OCTOBER 2006

Share Link: