Si8752 replacement for  VOM1271T  mosfet driver.

June 2017 PROJECT:

OPTO: VOM1271
FET:  FDP083N15A_F102
ORDER FROM Newark.com    24 June 2017

95T0014 	

12
	FDP083N15A_F102 	FAIRCHILD SEMICONDUCTOR  FDP083N15A_F102  MOSFET Transistor, N Channel, 117 A, 150 V, 0.00685 ohm, 10 V, 2 V
45W6889 	

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	VOM1271T 	VISHAY  VOM1271T  MOSFET Driver, High Side, 47 ľA, SOP-4


wilhelm: IPB025N-10N3

http://www.diyaudio.com/forums/solid-state/308128-speaker-protection-kit-under-5-a-6.html

Vrystaat:

The Mosfets: IRFB4115 GPBF
Opto's : TLP3906


Dacz: OPTO: V621-302E


VOM1271  - fastest optocoupler


mosfet good for DC prot:
http://www.newark.com/fairchild-semiconductor/fdp083n15a-f102/mosfet-n-channel-150v-0-00685ohm/dp/95T0014




post #178

http://www.diyaudio.com/forums/solid-state/191449-output-relays-18.html

This is based around the FR3607 MOSFET produced by International Rectifier and the
ASSR-V622 MOSFET driver produced by Avago.
The delay and detector is based on the design by Rod Elliott.
I'd had Rod's design implemented around some Omron sealed relays,
but after a year things started to act up.


I decided to use the AVAGO photovoltaic coupler type no ASSR-V621 (from Farnell)
and the IRF2907 FET which offers a "typical" Rds of around 3.5m?.
This figure is quoted with 10 volts across gate and source. As each relay would
use one ASSR-V621 i decided to connect both photovoltaic cells in series to
maximise the available drive voltage.



=========

In general, you are seeking for a MOSFET with very high Vdsmax, very low Rdson and very high Idmax. Regarding Vdsmax, it must be higher than the sum of positive and negative supply rail voltage, and the output should be provided by clamping diodes connected to supply rails, reverse polarized. My tips are

Type Vdsmax Rdson Idmax
IRFB1227 200V 0.0197ohm 130A
IRFP90N20D 200V 0.023ohm 94A

Thanks Pavel! two of these are available from my usual source

IRFP90N20D 200V 0.023ohm 94A - $4.55
IRFS59N10D 100V 0.025ohm 59A - $2.53

I also found this, but there are concerns about it not being a major manufacturer ?

IPD200N15N3G 150V 0.020ohm 50A- $2.51

and of more 'repute'

IRFB4227PBF 200V 0.024ohm 65A - $2.89



The turn off time for the TLP190B that Bigun mentions is quoted as a 1 millisecond.
The Avago ASSR-V621 that I used specifically has an "active turn off circuit"
and is quoted at 0.03 millisecond off and 0.3 millisecond turn on.
Substantially better.

ASSR-V621-002E   rae dip-8 

====

pavel:

In case you are going to build the circuit, you might consider to increase R1 to 100k and C3, C4 to 47uF. This for the reason to prevent false triggering of the circuit during high amplitude assymetrical waves at very low frequencies. But even original values would work OK. 



###########
http://www.diyaudio.com/forums/solid-state/288941-speaker-protection-3.html

apv1122 photovoltaic optoisolator has turn off spec of 0.1 ms with 1000 pf load. They were in stock at digikey. I'm feeling great I found those first. However nfet FDP52N20 has <2900 pf gate capacitance. Now if the FDP52n20 has enough SOA to shut off a 1000 amp short circuit current out of 10000 uf @ 85 V. I've been thinking of paralleling the output of the APV1122 with an ordinary op amp driven by the notQ of the latch IC, to drain off the stored gate charge faster. One of my goals with rail fets is to save the other $45 of nine output transitors when one shorts out.
How big a heat sink are you using on your shut off nfets? I'm thinking of using the one out of a PCAT ATX supply with room for 4 TO220's on it. On resistance of a nfet is <.05 ohms, normal current is <22 amps. That is 25 watts. per Nfet I've got a fan. I do have independent DC detectors on the two channels, the only things the two channels fault circuit share are the 5 v power supply and the 74hc74 fault latch.