Mosfet Gate Driver LT1160

Thread Starter

ashkarmalik

Joined Jul 1, 2012
89
I want to design a 3 PHASE Bridge For My Motor Setup ,So I am designing a Setup that would have 3 Mosfet drivers coupled with 6 Mosfets.
The Thing is that I want to know how To test the high side of the gate driver,I can Measure the low side by applying the +12v on 0v on the Input Sides But I cant measure the Upper side voltage of the Gate driver . What is the Method to measure the Working of the gate driver properly.
 

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crutschow

Joined Mar 14, 2008
25,259
The correct method is to use a differential oscilloscope probe to measure the MOSFET gate-source voltage.
To do this with a standard two-channel oscilloscope, you connect one channel probe to the gate and the other channel probe to the source.
Set both channels to the same sensitivity and invert the polarity of one of the channels.
Set the mode to add the two channels on the display.

The limitation of this is any slight gain variation between the two channels.
You can check that by connecting the two probes to the same signal and see how much of it comes through.
You can minimize that feedthrough by setting one of the channels to variable gain and adjusting for minimum output under these conditions.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
89
Thank You for your Quick Reply Crutschow and Alec_t,
Now I want to clear out that if I provide 20khz 50% Signal into lower side drive and toggle the upper side driver with 20Hz signal the whole drive would be checked?
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
89
I mean I don't have a 2 probe based Oscilloscope,So what Should be the method to basically run the Mosfet driver without implementing any complex circuit to turn on the Drive on .
 

Alec_t

Joined Sep 17, 2013
11,517
if I provide 20khz 50% Signal into lower side drive and toggle the upper side driver with 20Hz signal the whole drive would be checked?
I think you'd have the whole drive wrecked, not checked :eek:. You have to make sure that the high-side and low-side IGBTs never get switched on simultaneously, or you would have damaging shoot-through.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
89
Ok then, I should Use a complementary PWM to be supplied into the Mosfet Driver With a little Dead Time in between to check the drive! Right.
 
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