User Manual

AP2004
PWM BUCK CONTROLLER
AP2004 Rev. 3 5 of 8 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
Electrical Characteristics (Continued) (T
A
= 25ºC, V
CC
= 6V, f = 200 Khz)
Output section
Symbol Parameter Conditions Min Typ. Max Unit
I
LEAK
Leakage current V
O
= 25V 10 µA
I
DRV
Sink current V
IN
= 20V 200 mA
Source current V
IN
= 20V 200 mA
V
SAT
Output saturation voltage I
O
= 10 mA 1.0 1.5 V
I
SC
Short-circuit output current V
O
= 6V 120 mA
PWM comparator
Symbol Parameter Conditions Min Typ. Max Unit
V
T0
Input threshold voltage at f = 10 KHz
(COMP)
CT 0.6 0.7 V
V
T100
Maximum duty cycle 1.2 1.3 V
Total device
Symbol Parameter Conditions Min Typ. Max Unit
I
CCA
Average supply current C
T
= 270pF 6 10 mA
Soft Start
Symbol Parameter Conditions Min Typ. Max Unit
V
SS
Soft-start Voltage 2.3 V
I
SS
Constant Charge Current 20 µA
Typical Application Circuit
L1
22uH
Output
5V/5A
C2
10nF
Optional
Vcc = 12V
P mos
Q1
1 2 3 4 FB
C1
470uF
R3 1K~30K
AF9435P
AF4835P
R1
OUT
VCC COMP
GND
SCP
SS
CT
9K
5A
C4
50nF
Optional
R2
C3
470uF
Step-Down DC/DC converter
8 7 6 5
C6 220nF
C5 50nF
C4 270pF
3K
Vout=Vref ⎟
⎠
⎞
⎜
⎝
⎛
+
2
1
1
R
R