Chopper Regulators
s Block Diagram
1 VIN
Voltage
regulator
PWM COMP
+
–
ON/OFF
circuit
F/F
––
Q
Over current
R
detecting
circuit
S
–
+
Over current
detecting
circuit
ERROR AMP.
Vref
3 COM
s Step Down Type Circuit Diagram (5V output)
2 VOUT
5 ON/OFF
4 OADJ
VIN
8~35V
1
+
CIN
100µF
4
PQ1CZ1
3
2
L 210 µH
5
RS
CS
R2
3kΩ
D
R1
1kΩ
ON/OFF control signal
s Polarity Inversion Type Circuit Diagram (–5V output)
VO=5V
+
CO
470µF
RS<=50kΩ
VIN
5 to 30V
1
+
CIN
100µF
4
PQ1CZ1
3
2
L 130µH
5
RS
CS
R2
3kΩ
D
R1
1kΩ
ON/OFF control signal
+
CO
2200µF
RS<=50kΩ
VO=–5V
PQ1CZ1