HA16138PS Hitachi Semiconductor (acquired by Renesas), HA16138PS Datasheet - Page 15

• Manufacturer Part Number: HA16138PS
• Description: Ac/dc Switching Converter Controller ic With High-voltage Power MOSFET
• Manufacturer: Hitachi Semiconductor (acquired by Renesas)

Application Circuit Examples 1
The application circuit example shown here detects the secondary-side output voltage of a flyback power
supply. Secondary-side output voltage detection and feedback are performed by a shunt regulator and
photocoupler.
When the OVP latch function is used for secondary-side output voltage overvoltage protection, the FB pin
should be pulled up to VDD by the shunt regulator and photocoupler.
AC
INPUT
*
The secondary-side output voltage is stabilized at a
value determined by the bleeder resistance of the
secondary-side shunt regulator.
VOUT(reg) = Vref(shunt)
0.1
: Primary GND
: Secondary GND
OVP feedback circuit
Line Filter
= 2.5V
= 5.0V
2.4k + 2.4k
400V
100
R1
120k
2.4k
2200p
+
R11 + R12
VR
15V
VR
260V
R12
+
C1
47
20V
51k
Transformer
P: 90T / 1.43mH
S: 6T / 8.1 H
B: 14T / 30.8 H
1
2
3
4
P
B
DRAIN
DRAIN
VDD
FB
HA16138PS
S
SOURCE
SBD
HRW26F
COMP
SGND
560
25V
CT
When the OVP latch function is used, the secondary-side
voltage is detected by the shunt regulator, and feedback
to the FB pin is performed by the photocoupler. The OVP
detection level is determined by the following formula.
VOUT(ovp) = Vref(shunt)
180
+
8
7
6
5
15
25V
OVP detection circuit (7.4V)
R2
15k
+
= 2.5V
= 7.4V
C2
2200p
K
A
HA17431VP
REF
R3
330
R4
1.8k
C4
0.022
C3
220p
4.7k + 2.4k
R5
3.3k
2.4k
R6
4.7k
R7
2.4k
Photo
coupler
R6 + R7
R7
HA16138PS
K
A
HA17431VP
REF
R8
330
R9
1.8k
C5
3.3
R10
3.3k
Units R:
DC
OUTPUT
5V/2A
R11
2.4k
R12
2.4k
C: F
+
15