AMC3843B ETC, AMC3843B Datasheet - Page 6

• Manufacturer Part Number: AMC3843B
• Description: (AMC3842B / AMC3843B) CURRENT MODE PWM CONTROLLER
• Manufacturer: ETC

AMC DOC. #: AMC3842B_C (LF)
March 2004
Copyright © 2002, ADD Microtech Corp.
Fig. 2. Error Amplifier Configuration
amplifier can source or sink up to 0.5mA
Fig. 4. Open-loop laboratory test fixture:
Z
i
currents associated with capacitive loads. Timing and bypass capacitors should be connected to GND pin
in a single point ground. The transistor and 5K potentiometer are used to sample the oscillator waveform
and apply an adjustable ramp to the I
Error AMP
Z
f
Adjust
4.7K
4.7K
COMP
1K
V
FB
R
2.5V
S
100K
Fig. 1. Current Sense Circuit
Adjust
I
2N2222
SENSE
R
Error
Amp
5K
f
Peak current (I
C
f
Application Information
SENSE
COMP
I
- the
GND
SENSE
0.5mA
R
Careful grounding techniques are necessary for high peak
T
Error
Amp
pin
COMP
I
R
V
SENSE
T
FB
/C
C
T
S
Output
T
) is set by: I
6
GND
V
V
REF
CC
C
2R
URRENT
R
S(MAX)
0.1µF
= 1V/R
1V
Fig. 3. Oscillator Section
For R
M
S
0.1µF
R
Current
Sense
Comparator
V
GND
ODE
T
/C
T
REF
< 5K, f =
1K,
1W
AMC3842B/43B
T
PWM C
R
1.72
C
R
T
T
C
T
T
V
V
Output
GND
REF
CC
ONTROLLER
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