amc3842b ADDtek Corp, amc3842b Datasheet - Page 7

• Manufacturer Part Number: amc3842b
• Description: Current Mode Controller
• Manufacturer: ADDtek Corp

Copyright © 2006 ADDtek Corp.
Fig. 2. Error Amplifier Configuration
amplifier can source or sink up to 0.5mA
Fig. 4. Open-loop laboratory test fixture:
Z
i
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
COMP
4.7K
1K
V
FB
2.5V
R
S
SENSE
100K
Fig. 1. Current Sense Circuit
Adjust
Error
Amp
I
2N2222
SENSE
R
pin
5K
f
APPLICATION INFORMATION
Peak current (I
C
f
- the
0.5mA
COMP
I
GND
SENSE
Careful grounding techniques are necessary for high peak currents
R
T
Error
Amp
COMP
I
R
V
SENSE
T
FB
/C
S
C
T
) is set by: I
T
Output
7
GND
V
V
REF
CC
2R
S(MAX)
R
AMC3842B/43B/44B/45B
= 1V/R
0.1µF
Fig. 3. Oscillator Section
1V
For R
S
0.1µF
R
Current
Sense
Comparator
V
GND
T
T
/C
< 5K, f =
REF
1K,
1W
T
DD019_F -- OCTOBER 2006
R
1.72
T
C
R
C
T
T
T
V
V
Output
GND
REF
CC