HA16114P Datasheet, PDF (33/38 Pages) Hitachi Semiconductor – Switching Regulator for Chopper Type DC/DC Converter

Application Examples (2)
HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
• External Synchronization with Primary-Control AC/DC Converter
(1) Combination with a flyback AC/DC converter (simplified schematic)
HRA83
Commer-
cial AC
+
1S2076A
−
+
Error amp. ^VIN
−
OUT
+
CL(CS)
Transformer
1S2076A
HRP24
D _SBD
R₁
+
−
R₂
2
SYNC
V_IN 10
HA16114,
HA16120 _{CL 11}
GND OUT P.GND
1
9
8
+
Main DC
output
−
Primary AC/DC converter IC
(HA16107, HA17384, etc.)
To A of SBD
2SJ296
Step-down
output
(HA16114)
K
A SBD
HRP24
+
+ _{Sub DC}
− output
−
This is one example of a circuit that uses the features of the HA16114/120 by operating in
synchronization with a flyback AC/DC converter. Note the following design points concerning the
circuit from the secondary side of the transformer to the SYNC pin of the HA16114/120.
• Diode D prevents reverse current. Always insert a diode here. Use a general-purpose switching
diode.
• Resistors R₁ and R₂ form a voltage divider to ensure that the input voltage swing at the SYNC pin
does not exceed Vref (2.5 V). To maintain operating speed, R₁ + R₂ should not exceed 10 kΩ.
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