IC-SP-06027 R1
VS
VS1
VS2
VS1
VS2
VS
MU
MV
MW
MU
MV
MW
Motor
Motor
RS
GH1
RS
GH2
RS
GH1
RS
GH2
Fig. 5-4. Example to Reflux current
Fig. 5-5. Example to Power regenerative current
(c) Noises of the RS pin
The RS pin contains a filter having a time constant of about 1μs.
If the system malfunctions due to a noise, an effective solution is to add a filter externally. However,
beware that the external filter increases the delay time before the IGBT turns off.
VB
typ. 220kΩ
RS Input resistor
(Note)
(Inside the IC)
typ. 5pF
Vref
Comparator
typ. 200kΩ
GH1,
GH2
Rs
Rf
Cf
External filter
-
+
S
R
Latch
Interlock clock trigge
r
Note) See the section "RS" of Pin Name in Table 4.2 for the input resistor value.
Fig. 5-6. Example to add external filter
(d) Precautions on wiring
Make the wiring of the shunt resistor Rs as short as possible. The GH1 and GH2 are connected to the
IGBT emitter. If the wiring has a high resistance or inductance component, the emitter potential of the
IGBT changes, perhaps resulting in the IGBT malfunctioning.
Connect the GH1 and GH2 pins near the pin. If the resistance components of the wiring is poor
balanced between the GH1 and GH2 pins and the shunt resistor Rs, the current limit levels in each
phase may not be equal.
(e) Motor lock
This IC does not contain a protection function against motor lock.
If the motor locks, the phase where the output IGBT turns on is fixed, resulting in a constant
current-limited state. This produces a major loss, which results in IC temperature increase and IC
gets destroyed.
(3) Protection against short-circuit
This IC does not contain a protection function against short-circuits (such as load short-circuit, earth fault,
and short-circuit between the top and bottom arms).
A short-circuit produces a large current exceeding the maximum rating in the IC. The IC may therefore
get destroyed.
-
15
-
Home Index Pages Text
Previous Next
Pages: Home Index