pq1cf2 ETC-unknow, pq1cf2 Datasheet - Page 7

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

Chopper Regulators
Fig. 5
Please design ripple current ( I
to be the good balance of inductor and output capacitor.
Please select the inductor which the current rating is at least 1.2 times greater than maximum peak current.
qAdjustment of output voltage
wCoil
Precautions in Designing
Output voltage can be adjustable by attaching external resistor R
range is as follows.
<<Step-down voltage type>>
In first time, the ratio of output transistor on time (T
equations.
a) Step-down voltage type
b) Polarity inversion type
D(Duty)= ––––––––– = –––––––––––
L(Coil inductance)= ––––––––––– x D x ––
Iswp(Peak value of coil current)= I
V
Maximum value is limited to 0.9 x (V
V
Output voltage |V
O
O
V
=V
= –V
O
is limited to 40–V
ref
T(cycle)
ref
to 35V
T
to –30V
ON
Output transistor
Switching current
Diode current
Coil current
(continuous mode)
Coil current
(non-continuous mode)
V
O
IN
| =V
V
–V
IN
IN
V
ref
–V
SAT
L
I
L
O
–V
)set up about 20 to 30% of output current (I
+V
–V
x (1+R
SAT
F
F
O
+V
by input voltage.
F
O
2
+ ––– = I
/R
2
I
1
L
) (V)
0
0
IN
f
1
V
V
V
V
f
O
O
–V
IN
O
F
SAT
ON
O
+ ––––––––––– x D x ––
SAT
: Input voltage
: Output voltage
: Forward voltage of catch-diode
: V
: Oscillation frequency
V
) by input voltage.
IN
IN
OFF
ON
–V
Peak value of coil current (Iswp)
-V
2 x L
(H)
)and catch-diode on time (T
OUT
SAT
–V
voltage at transistor ON
ON
O
1
OFF
and R
f
1
O
2
ON
o
to e, r, or output terminal. Adjustable
),and set up continuous mode. So, it is said
OFF
OFF
) is obtained by the following
Io
I
L
PQ1CF2