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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.
.
rn
ce
RS
i Usphase
(b)
zs
6)
QOpvt
—
Cen
EL
2
ee)
(ee
(6)
Qevt
D403
D404
at C402
a
vrpes
QO Ewr
D405
D406
z C403.
Fig. 7-1
current
Ox
Fig. 7-2
Forward Current Waveform at Point @
@
When pin @ of the micro computer goes "HI" > "LO", a photocoupler between PQ2 pins © and @ turns
on and current flows to terminal @ — R401 — PQ2 - R404 — power module's Bu* terminals —> Eut
terminals - D402 — D401 — terminal © 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 moduie's positive @ 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 @, @ and @ of the micro computer and are input to pins @ of photocouplers PQ2 - PQ4.
ee LS
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