Re: MOSFET driver killed with no particular reason

All Bridge drivers have the potential for short-circuit failure unless
there is a safety circuit to prevent this. With separate drive
circuits for simultaneous complementary switching , it is cruicial to
control the switch delay to allow some dead-time in the switches and
have each one protected for reverse pulses. Asymmetric delays for
rising and falling pulses and reactive loads all contribute to this
risk. Try to design the pulse delays so that the turn-off delay is
always shorter than the complementary switch's turn-on delay. This can
be controlled by adding turn-on delay only in the pre-driver signal to
compensate for the natural longer off delay of the switch. Examine
worst case time delays with temperature effects and best case to
calculate the dead-time needed to avoid short-circuiting the high-side
and low side switches thru each other to power. A power transistor
will have a safe operating area for voltage and current but also look
for deratings from thermal effects and pulse speed. Once these limits
are all observed, your MOSFETs will last a long happy life.

Tony
EE'75

.

Relevant Pages

  • Re: Light sensitive relay switch alternative?
    ... >>>for a smaller delay. ... I've noticed that it takes longer to switch one way than back ... >to design - it is just resistive voltage dividers and basic ... >When LDR has high resistance, ...
    (sci.electronics.design)
  • Re: Dark Week Time Wasting Thread: Inauguration Edition
    ... Key senators have reached a compromise on a bill that would delay the nation's switch to all-digital television from next month until June 12. ... The National Telecommunications and Information Administration, which is running the coupon program, has hit its $1.34 billion funding limit and is now sending out new coupons only as unredeemed vouchers reach a 90-day expiration date. ...
    (alt.fan.letterman)
  • NEWS: Rabbit ears get reprieve with digital TV delay
    ... The switch from analog had been set for February 17; ... thanks to a delay in the digital TV transition approved by Congress ... watching television," said Rep. Roy Blunt, a Missouri Republican. ...
    (rec.outdoors.rv-travel)
  • Re: Need AD9501 replacement
    ... I have been using the Analog Devices AD9501 programmable delay chip in some gear, and was planning on designing a new board with them when I discovered they were obsolete, and becoming scarce. ... We use it to form a wide-range programmable one-shot, by using a CMOS switch to switch in resistors and caps, obtaining 5 overlapping ranges of time delay, from 0-50 ns to 0-15 us. ... Well, since the signals are not repetitive, we can't do any servo techniques. ...
    (sci.electronics.components)
  • Re: High voltage switch using IGBTs
    ... >> low side emitter to topside collector and get a switch that can cope ... >> pulses as square as possible. ... intended to conduct before the IGBT's voltage limit is reached. ... You can choose small TVS parts to minimize dynamic power losses ...
    (sci.electronics.design)