pm75cs1d120 Mitsumi Electronics, Corp., pm75cs1d120 Datasheet - Page 36

• Manufacturer Part Number: pm75cs1d120
• Description: Mitsubishi Ipm L1/s1-series Application Note Igbt Modules
• Manufacturer: Mitsumi Electronics, Corp.

(5) Notice of using opto coupler
The opto coupler can isolate the primary side and secondary side. But, this is not correct at the high frequency.
Because, opto coupler have a parasitic capacity between primary side and secondary side. When high dv/dt is
impressed, the pulse electric current flows from the primary side to the secondary side via the parasitic
capacity of opto coupler. This current sometimes turn on the opto coupler.
Therefore, it is important to design a circuit so that the LED will not turn on erroneously by this dv/dt.
When the input signal is OFF, make sure the circuit that the LED of primary side of opto coupler is with
low-impedance.
The recommended circuit doesn't make malfunction (LED of primary side of opto coupler is ON) because the
dv/dt current can not turn ON the LED of primary side of opto coupler.
Please consult the application-note of the opto coupler for the detailed instruction of the circuit around the opto
coupler.
OFF
The example of a circuitry which is not good
The example of the circuit to recommend
Parastic capacity
The LED is ON and
outputs extraordinarily ON signal.
36
dv/dt current
IPM
IPM
Using IPM
Sep. 2008