siliconmike said:
PSpice doesn't seem to take diode recovery times into consideration.
It is showing that 1N4007 diode is turning on in 0.5ns from a reverse
bias of 12V to a forward 4A current condition.
This is surprising. Any hints?
(I'm using student version of OrCAD PSpice.)
Mike
Hello Mike,
Recovery time means the reverse recovery time.
Reverse recovery time is the time required to switch off.
Stimulate the diode with a forward current of 1A.
Then switch to a negative voltage. Now look how long
the current flows in the reverse direction.
It's important to know the test setup if you want
check against any number from the datasheet.
A possible test circuit:
I_forward=1A, I_backward=1A
Voltage source _/-\_/-\_.... +10V/-10V, 50us on, 100us period
Series resistor with 9 Ohm
Diode connected to resistor and GND(0V).
Now you should get a few microseconds of turn-off delay.
I checked this with a 1N4002 model.
Best regards,
Helmut
PS: I use LTspice. It's an unlimited and free of charge
SPICE simulator with GUI(schematic entry and waveform viewer).
This is the test circuit: "1N4002_test.asc"
Just copy and paste it into a file named 1N4002_test.asc .
Remove additional line feeds caused by the mail programs.
Now you can open and run it with LTspice.
Version 4
SHEET 1 1352 680
WIRE -16 64 -128 64
WIRE 144 64 64 64
WIRE 512 64 144 64
WIRE -128 112 -128 64
WIRE 512 112 512 64
WIRE -128 240 -128 192
WIRE 512 240 512 176
WIRE 512 240 -128 240
WIRE -128 272 -128 240
FLAG -128 272 0
FLAG 144 64 IND1
SYMBOL diode 496 112 R0
SYMATTR InstName D1
SYMATTR Value DI_1N4002
SYMBOL res -32 80 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 9
SYMBOL voltage -128 96 R0
SYMATTR InstName V1
SYMATTR Value PULSE(-10 11 1u 10n 10n 50u 100u)
TEXT -144 384 Left 0 !.MODEL DI_1N4002 D ( IS=76.9p RS=42.0m BV=100 IBV=5.00u CJO=39.8p M=0.333 N=1.45 TT=4.32u )
TEXT -136 -24 Left 0 !.tran 0 300u 0 .01u
TEXT -136 -64 Left 0 ;Plot I(D1)
TEXT -144 344 Left 0 ;*SRC=1N4002;DI_1N4002;Diodes;Si; 100V 1.00A 3.00us Diodes, Inc. diode