Mysterious current flow

[kchriste]

I'm surprised it works at all with Vdd (pin9) of the IR2113 connected to ground and Vss(pin13) connected to 11V! Or is the **broken link removed** I'm looking at out to lunch?

 

[chris414]

Wow I really don't know how that happened... it all works fine though?? How very strange. Could this be the cause of random short circuits?

 

[jrz126]

You must be drawing some serious power if your 25W resistors are exploding and not blowing the fuse. Is it possible you could have shorted the resistors across the battery (bypassing the fuse)? In any case, you should mount your fuse as close as possible to your power source.

I built an h-bridge once for an inverted pendulum project once. I blew a couple mosfets and they shorted, causing shoot-through and nearly catching my breadboard on fire. I added a current sensing shutdown circuit after that. I've got a bunch of pics and stuff here:**broken link removed**

 

[toxsick]

Better late.. but I dont know if this is any help to you.

I have used several times a circuit in thailand from Fururekit/maxxtronic

it is a DC Motor Controller 12/24v jumper selectable... with a Pot for adjustment..
the Circuit is rated at 15A but I am sure you can adapt the circuit improve the circuit or try the circuit

Here is a LINK
**broken link removed**

I can make a photo of the Manual.. the circuit is shown but the text is all in THAI.

good luck..

Let me know if you need this document!

EDIT:
Additional info...
the transistor code is IRF3205
the IC is LM324N

 

[toxsick]

oh!.. I used this to drive a Motor from an A/C fan for a car.. I made a shaft and used a plastic fanblade from a fan and used it as a boat motor!
it works great just dont get the circuit wet... hahaha

 

[Apple-iPad]

very helpful

 

[chris414]

I'm surprised it works at all with Vdd (pin9) of the IR2113 connected to ground and Vss(pin13) connected to 11V! Or is the **broken link removed** I'm looking at out to lunch?

Sorry I labelled my schematic wrong, will correct it

 

[chris414]

I'm still not sure what the problem is, I've implemented the changes suggested but no one seems to be able to diagnose the cause of the seemingly random short circuits. I'm going to add in some current sensing circuitry - at least if it happens again I'll hopefully not explode anything I was thinking something as simple as a transistor that senses when a certain voltage across the 0.7ohm resistors is reached - my question then is how to stop the flow of current. I was thinking putting a transistor between the mosfet gates and ground, and the transistor turns on when the current sensing circuit is triggered, thereby closing all the mosfet gates. Would this work against most short circuit scenarios?

(My mosfets are rated to carry more current than the 0.7ohm resistance will allow the batteries to supply, so I am not worried about frying the mosfets. Also I plan to limit the current to 10amps for now, when my 0.7ohm resistor combination can carry 15amps at max power)

 

[jrz126]

Take a look at my diagram here:**broken link removed**

I had my sense resistors (4 0.1 ohm in parallel) feed into an op-amp which would trigger a flip-flop. The flipflop output is connected to the shutdown pin of the driver ICs (I used IR21844's), keeping the drivers shut down until the flip flop is reset by pushing the button.

 

[canadaelk]

In an earlier post I suggested Vdd of U1 and U2 to 24V. This should have read Vcc. I would also take VB of U1 & U2 t0 the 45V rail.
Good luck, E