Sharp AY-ZP35PR Service Manual page 20

The power supply for the subsequent stages is charged while the lower-phase IGBT is ON in ordinary compressor drive control.
Initial charge period
V
V
V
4.1.2 DC over current detection circuit
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at this resistance is input to IPM CIN pin (26). Then, the gate voltage of the lower-phase IGBT (LU, LV, LW) inside the IPM turns OFF to
cut off the over current. At the same time, an L output of about 1.8 ms is generated from IPM Fo pin (24), and this results in an L input
to overcurrent detection input pin (34) of the microcomputer (IC1) and turns OFF the PWM signal output (IC1 pins (51) through (56)) to
the IGBT gate.
Protection circuit status
(Lower phase)
Internal IGBT gate
Output current Ic (A)
Sense voltage relative
to shunt resistance
Error output Fo
Charging current group
Bootstrap capacitor
DB
High-voltage-withstanding,
high-speed recovery diode
D
( )
CIN n
Bootstrap circuit
(About 25 A)
a1
SC reference voltage
(HU,HV,HW)
HVIC
(LU,LV,LW)
LVIC
SET
SC
Delay by CR time constant circuit
About 1.8 ms
2-15
AY-ZP35PR
P(Vcc)
U,V,W,
N-side
IGBT
N(GND
RESET