HA16120 RENESAS [Renesas Technology Corp], HA16120 Datasheet - Page 34

• Manufacturer Part Number: HA16120
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: RENESAS [Renesas Technology Corp]

HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
Application Examples (3)
Rev.2.0, Sep.18.2003, page 34 of 37
(2) Combination with a forward AC/DC converter (simplified schematic)
Input
This circuit illustrates the combination of the HA16114/120 with a forward AC/DC converter. The
HA16114/120 synchronizes with the falling edge of the external sync signal, so with a forward
transformer, the sync pulses must be inverted. In the diagram, this is done by an external circuit
consisting of the following components:
External Synchronization with Primary-Control AC/DC Converter (cont.)
Q:
R
R
ZD:
Switching transformer
1
3
Coil
Coil
Coil
Coil
:
and R
HA16107,
HA16666 etc.
DFG1C8
A
B
C
D
2
Primary, for main
Secondary, for output
Tertiary, for IC
For reset
:
Transistor for inverting the pulses. Use a small-signal transistor.
These resistors form a voltage divider for driving the base of transistor Q. R
a path for base discharge, so that the transistor can turn off quickly.
Load resistor for transistor Q.
Zener diode for protecting the
C
D
A
B
R
R
1
2
6.2k
510
SYNC
2SC458
HRW26F
pin.
Q
R
3
SBD
module
ZD
390
SYNC
2
HA16114,
HA16120
GND
1
V
IN
FB
HA17431 and optocoupler
Feedback
section
V
OUT
10
IN
9
Other parts as
on previous page
2
also provides
Main DC
output
+