MOSFET heating problem in H-bridge

[kushal nandanwar]

I am trying to drive H-bridge using MC33883, but at more than 2A my upper side MOSFET get heating too much.

View attachment H-bridge1.pdf

 

[KlausST]

Hi,

what´s your switchng frequency?
Do you think it´s a good idea to connect those 10nF to the bridge output?

Klaus

 

[kushal nandanwar]

Hi,

what´s your switchng frequency?
Do you think it´s a good idea to connect those 10nF to the bridge output?

Klaus

1 Hz to 5 KHz
10nF recommendation in circuit diagram
page no 18View attachment 75712565.pdf

 

[crutschow]

It looks like you have the connections for Vcc and Vcc2 reversed.
Vcc should go to the bridge voltage.
Vcc2 should go to the chip power.

 

[kushal nandanwar]

At what frequency are the MOSFETs overheating?

When current rise more than 2A, I think upper driver is not working.

Because MOSFET i have used Si4062DY
provide 0.0042 at VGS = 10 V

 

[c_mitra]

These are noise bypass caps- they prevent spurious triggering (I guess)

 

[crutschow]

See my update to post #4.

 

[c_mitra]

1 Hz to 5 KHz

Any specific reason for this choice?

 

[kushal nandanwar]

It looks like you have the connections for Vcc and Vcc2 reversed.
Vcc should go to the bridge voltage.
Vcc2 should go to the chip power.

Vcc and Vcc2 both in my circuit connected to same power supply 12VDC

 

[crutschow]

If it's wired as you show and the part values are correct (double check the value C99 that it is 470nF and not 470pF) then I see no obvious reason that the upper MOSFETs should get hot.

 

[kushal nandanwar]

If it's wired as you show and the part values are correct (double check the value C99 that it is 470nF and not 470pF) then I see no obvious reason that the upper MOSFETs should get hot.

yes it's 470nf

 

[kushal nandanwar]

I check today driver heating too much, if I increase current more than 1A.

 

[kushal nandanwar]

waveform of H-bridgeView attachment q109.bmpView attachment q710.bmpView attachment q78.bmpView attachment q98.bmp

 

[kushal nandanwar]

waveform of H-bridgeView attachment 126748View attachment 126749View attachment 126746View attachment 126747View attachment 126745View attachment 126744

In attached image can be seen that 3 MOSFET is getting ON in which one is with opposite face.well according to logic only two MOSFET have to get ON, which are diagonally opposite.

 

[KlausST]

Hi,

I just see some curves on your scope pictures. But without description I don't know what signals they show.

Please post a description to your pictures.

Klaus

 

[kushal nandanwar]

Hi,

I just see some curves on your scope pictures. But without description I don't know what signals they show.

Please post a description to your pictures.

Klaus

As you can see Image, there is in each Image written q78, q98, q109 and on same Image you can find circuit diagram of H-bridge where you get Q9,Q10 and Q7, Input signal to gate for each MOSFET is shown in DSO image.

 

[kushal nandanwar]

OK I check signal at DSO and find that my upper lever MOSFET voltage from source to gate is not getting more than 2VDC, according to MOSFET use in H-bridge, voltage between source and gate should be more than 6VDC to get MOSFET fully ON.

 

[KlausST]

Hi,

You have 150 ohms gate resistors.
If the voltage at the resistor on the driver side is higher than on the FET side, then there is current. Maybe caused my a defective FET.

Klaus

 

[kushal nandanwar]

Hi,

You have 150 ohms gate resistors.
If the voltage at the resistor on the driver side is higher than on the FET side, then there is current. Maybe caused my a defective FET.

Klaus

I replace MOSFET with new one but there is no change.