Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Why are my gate drivers breaking

Status
Not open for further replies.

Bakez

Member level 1
Joined
Mar 23, 2010
Messages
33
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,616
I have an single phase inverter (or H-Bridge) with Silicon Carbide MOSFETs

The gate drivers have two DCDC power supplies in order to create a -2V to 20V gate voltage swing (one for the negative and one for the positive).

I am running all the gate drivers from one supply. When I turn on the inverter with a low input voltage, the gate drivers work fine, however as I increase the input voltage the gate drivers start to draw more and more current from the power supply and also the voltage the power supply outputs drop dramatically. Does anyone know why this is?

Is it because my gate driver is heating up, or needing to draw more power when the MOSFETs are being switched at a higher voltage or other reasons?

I think maybe the fact I have absolutely no input filter capacitor on any of the 8 DCDC converters that I am supplying out of one power supply could be a reason too.
 

nandhu015

Advanced Member level 5
Joined
Feb 11, 2006
Messages
1,965
Helped
300
Reputation
600
Reaction score
224
Trophy points
1,353
Location
India
Activity points
9,813
Post your full circuit diagram which will help to find the problem
 

Tahmid

Advanced Member level 5
Joined
Jun 17, 2008
Messages
4,758
Helped
1,791
Reputation
3,574
Reaction score
1,650
Trophy points
1,393
Location
Silicon Valley, California, USA (from Dhaka, Bangl
Activity points
30,545
It is difficult to suggest solutions without taking a look at the circuit diagram.

At the output of the DC-DC converters, you should connect filter capacitors. Which DC-DC converter(s) are you using?

Does the gate driver drive the MOSFET with up to 20V? That might be a problem. What is the VGS(max) of the MOSFET(s) you are using? If it is about 20V (or lower), reduce the DC-DC converter supply voltage to 12V or 15V.

A resistor (1k is good) between the gate and source of each MOSFET should be used.
 

BradtheRad

Super Moderator
Staff member
Joined
Apr 1, 2011
Messages
13,804
Helped
2,738
Reputation
5,473
Reaction score
2,648
Trophy points
1,393
Location
Minneapolis, Minnesota, USA
Activity points
103,031
The waveform through the mosfets is worth checking.

If the waveform is at all ramp shaped, that means it is spending a greater portion of the cycle in resistive (linear) mode, and is dissipating watts as heat.

The greater output you ask from it, the more heat it generates.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top