AP3843N8 Anachip Corporation, AP3843N8 Datasheet - Page 5

• Manufacturer Part Number: AP3843N8
• Description: High Performance Current Mode PWM Controller
• Manufacturer: Anachip Corporation

High Performance Current Mode PWM Controller
Peak current(i
A small RC filter may be required to suppress switch transients.
Figure 4.
Figure 5 : Open Loop Test Circuit.
High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and
bypass apacitors should be connected close to pin 5 in a single point ground. The transistor and 5 KΩ
potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.
Figure 6 : Shutdown Techniques.
Anachip Corp.
www.anachip.com.tw
I
S
max ≈
ERROR AMP.
ADJUST
s
1.0V
) is determined by the formula
R
S
SHUTDOWN
4.7K
1K
4.7K
330K
100K
I
ADJUST
SENSE
2N2222
500K
1K
5K
TO CURRENT
SENSE RESISTOR
B
3
V
I
SENSE
R
REF
GROUND
T
2
3
4
for R
1
R
COMP.
V
I
R
SENSE
V
FB
T/
T
T
REF
/C
C
> 5KΩ f=
T
T
8
4
5
AP3842
5/8
C
T
SHUTDOWN
1.72
R
GROUND
T
OUTPUT
C
V
R
C
T
REF
T
T
V
i
8
7
6
5
0.1
uF
1 COMP
0.1
uF
A
AP3842/3/4/5
TW
1K
V
OUTPUT
Vi
GROUND
REF
Rev.1.0 Oct.11, 2004