HA16138PS Datasheet, PDF (7/20 Pages) Hitachi Semiconductor – AC/DC Switching Converter Controller IC With High-Voltage Power MOS FET

HA16138PS
Error Amplifier
The error amplifier comprises a constant-current source type Pch top differential amplifier. As the
inverting input (FB) pin and output (COMP) pin are provided as external pins, use for both a simple
flyback power supply back-up voltage feedback type and a high-precision secondary voltage detection type
is possible.
Current Sense Circuit
This is a 200 ns high-speed comparator circuit suitable for current mode control. The current sense
controller reference voltage depends on the COMP pin voltage, being always 1/3 of the COMP pin voltage.
Osc.
FF
Driver
Power
MOS FET
+
−
Current sense
comparator
−
2R
+
Error amplifier
R
300 ns
Delay circuit
Leading edge
blanking
Current sense
resistance
1/3 attenuator
Figure 2 Current Sense Peripheral Circuitry
Leading Edge Blanking Circuit
The on-chip leading edge blanking circuit masks the current sense comparator input signal for a period of
300 ns after the power MOS FET gate voltage goes high. This reduces the erroneous operation due to
spike-shaped noise caused by discharge of various capacitance components when the power MOS FET is
turned on.
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