Application circuit example
5.1 Guidelines
Input signals HIN, LIN are active high logic. A 375 kΩ (typ.) pull-down resistor is built-
in for each input. To prevent input signal oscillations, the wiring of each input should
be as short as possible and the use of RC filters (R1, C1) on each input signal is
suggested. The filters should be within a time constant of about 100 ns and placed as
close as possible to the IPM input pins.
The use of a bypass capacitor CVCC (aluminum or tantalum) can help to reduce the
transient circuit demand on the power supply. Besides, to reduce high frequency
switching noise distributed on the power lines, a decoupling capacitor C2 (100 to 220
nF, with low ESR and low ESL) should be placed as close as possible to the Vcc pin
and in parallel with the bypass capacitor.
The use of an RC filter (RSF, CSF) for circuit malfunction protection is recommended.
The time constant (RSF x CSF) should be set to 1 μs and the filter must be placed as
close as possible to the CIN pin.
The SD
is an input/output pin (open-drain type if used as output). A built-in thermistor
NTC is internally connected between the SD
pin and GND. The VSD-GND voltage
decreases as the temperature increases, due to the RSD pull-up resistor. In order to
keep the voltage always higher than the high level logic threshold, the pull-up resistor
is suggested to be set to 1 kΩ or 2.2 kΩ for an MCU power supply of 3.3 V or 5 V
respectively. The CSD capacitor of the filter on SD
should be fixed no higher than 3.3
nF in order to assure an SD
activation time of τ1 ≤ 500 ns and the filter should be
placed as close as possible to the SD
pin.
The decoupling capacitor C3 (from 100 to 220 nF, ceramic with low ESR and low
ESL), in parallel with each Cboot, filters high frequency disturbance. Both Cboot and C3
(if present) should be placed as close as possible to the U, V, W and Vboot pins.
Bootstrap negative electrodes should be connected to the U, V, W terminals directly
and separated from the main output wires.
To prevent overvoltage on the Vcc pin, a Zener diode (Dz1) can be used. Similarly, a
Zener diode (Dz2) can be placed on the Vboot pin in parallel with each Cboot.
The use of decoupling capacitor C4 (100 to 220 nF, with low ESR and low ESL) in
parallel with the electrolytic capacitor Cvdc is useful to prevent surge destruction. Both
capacitors C4 and Cvdc should be placed as close as possible to the IPM (C4 has
priority over Cvdc).
By integrating an application-specific type HVIC inside the module, direct coupling to
the MCU terminals without an optocoupler is possible.
Use low inductance shunt resistors for phase leg current sensing.
In order to avoid malfunctions, the wiring on N pins, the shunt resistor and PWR_GND
should be as short as possible.
The connection of SGN_GND to PWR_GND to one point only (close to the shunt
resistor terminal) can help to reduce the impact of power ground fluctuation.
These guidelines ensure the device specifications for application designs. For further
details, please refer to the relevant application note.