Application Note
21 of 53
V 1.0
2019-04-01
IM393 Application note
IM393 IPM Technical Description
Interface circuit and layout guide
Table 7
The recommended minimum circuit current of control power supply (Unit:[mA])
Item
The circuit current of +15 V control supply
The circuit current of +5 V logic supply
V
DD
≤ 20 V,
F
SW
≤ 20 kHz
90
45
4.4
Recommended layout for over-current protection (OCP) and short-
circuit protection (SCP) functions
It is recommended to make the I
TRIP
filter capacitor connections to the IM393-XX pins as short as possible. The
ITRIP filter capacitor should be connected to the COM pin directly without overlapping ground pattern. The
signal ground and power ground should be as short as possible and connected at only one point via the filter
capacitor of V
DD
line. The I
TRIP
function combined with the external shunt resistor can be used to detect over-
current events in the ground path that will result in damages to the IPM. The internal HVIC gate driver
continuously monitors the voltage on ITRIP pin. If this voltage exceeds the reference voltage (typ. 0.49 V), a
fault signal will be generated on the RFE pin and all six IGBTs will be turned OFF.
VDD line
5 or 3.3V line
(17) RFE
(16) ITRIP
(12) VDD
(18~23) HIN/LIN
(14,15) COM
(24~26) Nx
(1) P
CIPOS
TM
Tiny
Micro
Controller
Figure 14
Example of layout pattern for OCP and SCP functions
4.5
Recommended wiring of shunt resistor and snubber capacitor
External current-sensing resistors are applied to detect over-current of phase currents. A long wiring pattern
between the shunt resistors and IM393-XX will cause excessive surges that might damage the IPM-internal IC
and current-detection components. This may also distort the sensing signals that may lead to loss of control
when driving a motor. To decrease the pattern inductance, the wiring between the shunt resistors and the
IM393-XX should be as short as possible, and any loop should be avoided.
As shown in Figure 15, snubber capacitors should be installed in the right location so as to suppress surge
voltages effectively. Generally a high-frequency, non-inductive capacitor of around 0.1 ~ 0.22 µF is
recommended. If the snubber capacitor is installed in the wrong location, ‘1’ as shown in Figure 15, the snubber
capacitor cannot suppress the surge voltage effectively. If the capacitor is installed in location ‘2’, the charging
and discharging currents generated by wiring inductance and the snubber capacitor will appear on the shunt
resistor. This will impact the current-sensing signal, and the SC protection level will be a little lower than the
calculated design value. The “2” position surge suppression effect is greater than in locations ‘1’ or ‘3’. The ‘3’
position is a reasonable compromise with better suppression than in location ‘1’ without impacting the
current-sensing signal accuracy. For this reason, location ‘3’ is generally used.
