A little help for a simple mosfet H-bridge problem

Thread Starter

Optipook1

Joined Jul 25, 2017
63
I am new to electronics and this is my first post

Situation:
I would like to build my first robot as a summer project. Nearly all the mechanical part is complete(waiting for a piece) and now I'm turning my focus to the electrical side. I'm using Proteus 8.6 Demo. to draw the circuit and simulate.

Information:
-My inputs are coming from a RF receiver with a PT2262 decoder, with the module I have, I'm unable to send ore then two signals and no PWM.
-The motors are 12V brushed gear motors, each of them have a stall current of 2.19A.
-My power supply is a 12V 5.5A lead acid battery.


Problem:
When one input goes high, the opposite mosfets get really hot and eventually die out. I know it may seem like a silly problem but I cant seem to find the cause of it

Questions:
Can someone please explain to me what might be happening and why?
If there are any improvements or a way to "fix' the circuit that you might recommend?
Is there a way to calculate the pull-up/down resistors and filter capacitor, for a further time?

I am unable to get any other parts for this project, I do have a backup 2A L298N dual h-bridge motor driver module, just in case.
All help is appreciated!



 

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Thread Starter

Optipook1

Joined Jul 25, 2017
63
There are many attachments because I am unable to save nor export the file.
Thanks in advanced!

Oh, and my high side mosfets: IRF9530
My low side mosfets:IRL520
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
I notice a mistake in my original post, the RF module can only send one signal at a time and is unable to send any PWM.
 

crutschow

Joined Mar 14, 2008
25,664
So, the circuit I posted is usable and the difficulties I've had were in the wiring on my breadboard?
It would appear so.
I see no reason that the circuit you posted should not work properly with no significant heating of the MOSFETs.
I would double-check all the wiring against the schematic.
Particularly look at the MOSFET pinouts.

The value of R5 and R6 are a factor of 100 smaller than they need to be (the base current needs to be no more than about 1/10th the collector current for good saturation), but that should not cause any problems.
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
Are you able to verify that the two inputs are NEVER high at the same time?

With this H-bridge configuration, both inputs high causes the bridge to short out the power supply.
The next time that I will go simulate the circuit, I will double check if both inputs are high.
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
I have other questions that crossed my mind.
-Can I use NAND or AND gates to switch the p-channel mosfets? (no pwm)
-Can I use NAND or AND gates while using PWM? (with pwm)
 

crutschow

Joined Mar 14, 2008
25,664
I have other questions that crossed my mind.
-Can I use NAND or AND gates to switch the p-channel mosfets? (no pwm)
-Can I use NAND or AND gates while using PWM? (with pwm)
You mean without the transistor drivers?

You can if the gates are CD4000 series CMOS and they are operated from the H-bridge supply voltage (but that means there control inputs must also be that same voltage).
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
You mean without the transistor drivers?

You can if the gates are CD4000 series CMOS and they are operated from the H-bridge supply voltage (but that means there control inputs must also be that same voltage).
I was wondering about that because I have seen on the L298N schematic that they use AND gates. I was wondering to put the same feature on my board so I can put PWM and just HIGHs and LOWs.

Also, why does it have to be the CD4000 series CMOS and not the 7400 series?

Schematic of the l298n below
 

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Thread Starter

Optipook1

Joined Jul 25, 2017
63
If you want to drive the P-MOSFETs directly you need a logic family that can tolerate the H-bridge voltages.
Oh ok, I went to give a look at the datasheets, now I see. I'll give it a try and come back if I encounter any other problems.
Thanks for all the replies!
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
So I'm back, the h bridge works Great! The problem is now that I have a new pair of transmitter/receiver that I took from an old toy I had(pictures below), so now I'm able to send more than 1 input. I'm only able to get a few inches of range, I've added an npn(2n3904), that didn't help at all.
The frequency is 49Mhz, and I would like to increase the range to at least ~20 feet, 50 would be great!

How would I do that?
Would changing the antenna help on the receiver/transmitter?
Transmitter on left
 

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Thread Starter

Optipook1

Joined Jul 25, 2017
63
The transmitter has a 18 gauge copper enable wire, about 30 centimetres.
The receiver has a small antenna that is like a coil of copper wire around a(seems to be) iron core with a small white wire sticking out of it, pictures below.
Maybe the fact that the wire is enable affects the range?
Is there a way to boost the signal coming from the transmitter?
 

Thread Starter

Optipook1

Joined Jul 25, 2017
63
Oh, I forgot to mention that the IC's on both boards were labelled KL49M, but they came off when I was removing them from the toy.

Edit:
Should I start a new thread, because this is kind of getting off subject from the Mosfet circuit or is it fine, because on other sites (like electronicstackexchange) the replies/answers must stay within the subject.
 
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