Service manual

2-15
AY-ZP35PR
The power supply for the subsequent stages is charged while the lower-phase IGBT is ON in ordinary compressor drive control.
P(Vcc)
U,V,W,
V
D
VDB
VCIN(n)
N-side
IGBT
N(GND
Bootstrap capacitor
High-voltage-withstanding,
high-speed recovery diode
LVIC
(LU,LV,LW)
HVIC
(HU,HV,HW)
Bootstra
p
circuit
Initial charge period
Charging current group
4.1.2 DC over current detection circuit

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.
SET
RESET
(About 25 A)
SC
SC reference voltage
Delay by CR time constant circuit
About 1.8 ms
a1
Protection circuit status
Output current Ic (A)
Sense voltage relative
to shunt resistance
Error output Fo
(Lower phase)
Internal IGBT gate