Specifications

26
Dec. 20
Mitsubishi IPM-series Application Note
(4) Fo terminal of IPM
Fo is the output which shows the abnormal condition of IPM.
The extraordinary modes are overheating(OT), load ( the arm ) short circuit(SC), and control supply under
voltage(UV). Fo does not distinguish these kinds of failures.
The fault output is open collector type with its maximum sink current internally limited. When a fault condition
occurs the open collector device turns on allowing the fault terminal to sink current from the positive side of the
control supply. The inside of the Fo terminal is the open-collector composition which connected resistance
(1.5KΩ) in series.
Note )
If Fo is not used, the malfunction being able to be detected on the side of the system, passing away, it isn't
possible to do a protection-coordination with the system. For example, if Fo on the P-side is not used, then a
earth-short failure will not be able to protect in the system, and the earth-short occurs continuously. Because
IPM sometimes destroys when this condition continues, it is recommended to use all Fo terminals.
Fo terminal is connected with the comparator input circuit inside IPM. When leave this terminal open, there is
possibility that the noise invades from this terminal and cause malfunctions of the circuit inside IPM. In this case,
inserting a high frequency type condenser of about 0.1 μF between the Fo terminal and GND is effective. Also,
when not use Fo, in order not to undergo influence by the noise, connect it to 15 V control source.
Depending on the pattern layout of Fo, surge voltage over 20V is sometimes observed at the Fo terminal. Due
to this surge voltage, the electric strength is exaggerated and the LED part of the photo-coupler destroys. Be
careful of the pattern layout. If the surge voltage is difficult to be reduced, add a diode in the converse and
parallel(It refers to p1). To make low-impedance is important.
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surge voltage
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㪚㫆㫅㫋㫉㫆㫃㩷㫀㫅㫇㫌㫋㩷㫊㫀㪾㫅㪸㫃㩷
㩿㫇㫉㫀㫄㪸㫉㫐㩷㫊㫀㪻㪼㩷㫆㪽㩷㫇㪿㫆㫋㫆㩷
㪺㫆㫌㫇㫃㪼㫉㪀㩷
㩷㩷㩷㩷㩷㪌㪭㪆㪻㫀㫍㩷
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㪝㫆㩷㫋㪼㫉㫄㫀㫅㪸㫃㩷㫍㫆㫃㫋㪸㪾㪼㩷
㩷㩷㩷㩷㪌㪭㪆㪻㫀㫍㩷
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㩷
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㫋㫀㫄㪼㩷㪑㩷㪈㫌㫊㪆㪻㫀㫍㩷
㪝㫀㪾㪅㪐㪅㪊㩷㪫㪿㪼㩷㪼㫏㪸㫄㫇㫃㪼㩷㫆㪽㩷㫋㪿㪼㩷㪼㫏㫋㫉㪸㫆㫉㪻㫀㫅㪸㫉㫐㩷㫎㪸㫍㪼㪽㫆㫉㫄㩷㫆㪽㩷㫋㪿㪼㩷㪝㫆㩷㫋㪼㫉㫄㫀㫅㪸㫃㩷
(4) Example of photo coupler
The example of the photo-coupler recommended for IPM is shown below.
High speed photo coupler
High speed photo couplers are connected to the control input terminals of IPM.
When choosing photo coupler, pay attention to the parameters of response time (tpLH,tpHL) and CMR.
Choose the photo coupler that the value of tpLH,tpHL is less than 0.8us, and with high CMR.
Especially, ensure that the phenomena such as the ringing not occur.
For example)
PS9613 (NEC)
TLP559(IGM) (Toshiba)
The photo-coupler manufacturer sometimes has the IPM exclusive-goods ( another form name ) which
sorted out a characteristic. Please inquire the photo-coupler of IPM compatible for the malfunction prevention
when order.
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Using IPM