– 56 –
7. Drive Circuit
(1) Upper Arm Drive Circuit
● Fig. 7-1 shows the upper arm drive circuit.
The circuit configuration is completely the same for phases A, B and C.
5
6
1
8
5
7
2
6
C405
Bv
+
Ev
+
Bu
+
Eu
+
Bw
+
Ew
+
CN27
R402
R405
D403 D404
R408
C402
PQ3
+
–
5
6
1
a
A
b
8
7
2
C404
R401
R404
D401 D402
R407
C401
PQ2
+
–
5
6
1
8
9
7
2
10
A
A
C406
R403
R406
D405 D406
R409
C403
PQ4
+
–
Power module
U
+
phase
V
+
phase
W
+
phase
Fig. 7-1
Fig. 7-2 Forward Current Waveform at Point
1
2
Current at point
Forward
current
O
A
● When pin
e
of the micro computer goes "HI" [ "LO", a photocoupler between PQ2 pins 1 and 2 turns
on and current flows to terminal A [ R401 [ PQ2 [ R404 [ power module’s Bu
+
terminals [ Eu
+
terminals [ D402 [ D401 [ terminal B and drives the upper arm transistors. (Fig.7-2)
● As described in the rotor magnetic pole position detecting circuit, the upper arm drive circuit supplies
current to the bases of the transistors on the power module's positive e side which turn on or off according
to the position detection signals. The signals according to the position detection detection signals are
output from pins
e
,
r
and
t
of the micro computer and are input to pins 2 of photocouplers PQ2 - PQ4.
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