pq1cf2 ETC-unknow, pq1cf2 Datasheet - Page 5

• Manufacturer Part Number: pq1cf2
• Description: To-220 Type Chopper Regulator
• Manufacturer: ETC-unknow

Chopper Regulators
(1)ON/OFF control terminal
<ON/OFF control>
<Soft start>
<ON/OFF control with soft start up>
Polarity Inversion Type Circuit Diagram (-5V output)
Precaution for use
Fig. 1
ON/OFF control terminal t has ON/OFF function and soft start function. It operates by level of ON/OFF control
terminal voltage. (as shown in fig.1)
In the following circuit, when ON/OFF control terminal t becomes low by switching transistor Tr on, output voltage
may be turned OFF and the device becomes stand-by mode. Dissipation current at stand-by mode becomes TYP.150 A.
When capacitor Cs is added on terminal t, voltage of t is gradually getting upper because of internal constant current.
When voltage of t is higher than V
pulse width is. When main power supply turns on, output pulse gradually expands and output voltage will start softly.
Too large capacitance Cs causes long discharging time. In case of input voltage turning time from OFF to ON is short,
soft start function may not operate.
In this case, additional capacitor discharging circuit as shown in Fig.3 can make discharging time short. In order to set
voltage point A is higher than V
several dozens k .
For ON/OFF control with capacitor Cs, be careful not to destroy a transistor Tr by discharge current from Cs, adding a
resistor restricting discharge current of Cs.
V
5 to 30V
IN
C
100 F
+
IN
(V
1
(V
(V
PQ1CF2
3.55
2.25
THON
1.4
THH
THL
(V)
0
4
3
)
)
)
THH
C
2
5
(3.85V) in ordinary state, please design value of resistor R
S
THL
ON/OFF control
output, output pulse starts. And the higher voltage becomes, the wider output
R
S
Duty
D R
L
130 H
1
R
3k
1k
2
1
Duty
0%
R
2
C
2200 F
S
+
<=50k
O
Step–down voltage circuit
D
MAX
3
V
O
=–5V
time
1
2
3
Stand-by mode
OFF-state
Soft start
4
, R
5
from several k to
PQ1CF2