Hey guys check out this https://www.mouser.com/ProductDetail/Infineon-Technologies/BTN7960B?qs=9Vqdt%2BdHmfLOPvTrxYBUhw== this seems to be the chip responsible for the pwm correct me if im wrong.

 

That chip has since been replaced with https://www.infineon.com/cms/en/pro...-driver-ics/single-half-bridge-ics/btn8982ta/ heres a spec sheet on it, it says limitation level 55a does that mean 55amps? doesnt seem very likely as they burn out under hardly any load unless something else inside these modules is burning out

 

Here Ya go ........
I hope this isn't more complex than You were expecting.
Let me know anything You don't understand about it.
.
.
.

 

That chip has since been replaced with https://www.infineon.com/cms/en/pro...-driver-ics/single-half-bridge-ics/btn8982ta/ heres a spec sheet on it, it says limitation level 55a does that mean 55amps? doesnt seem very likely as they burn out under hardly any load unless something else inside these modules is burning out

Youre a genius, Im gonna break this down more tonight as I have to go to my boring day job but thank you so much. Youre a smart guy no doubt.

 

That module does not look like a simple PWM driver. Is the motor connected directly to that board? If so, how many wires of what sizes?

This project is beyond my expertise.

Bob

 

Problem: I have a module that controls fuel pressure but it only has the ability to deliver up to 15 amps before is over heats and toasts out.

You seem from what I just read about this module, going in the wrong direction on this. Just increasing the mosfet amperage is only going to make the problem bigger. I say that because of the heat/watts in a bigger one.

I seems to me the real thing would be to increase air flow or mount the board to a better heat sink one with cooling fins. It seems like the heat is killing the module not the actual mosfet being too small.

When a car is running the battery supplies 14.2v. more or less 15v

You have that wrong. The alternator is giving the ~14.5 volts into the electrical system, not the battery. after starting the battery can be removed from the car in most cases and it will still run off the alternator.

 

after starting the battery can be removed from the car in most cases and it will still run off the alternator

Or without a current limiting resistive load in the circuit the diodes in the alternator will emit their magic smoke. Which is why magnetos are typically used for no battery systems.

 

Youre a genius, Im gonna break this down more tonight as I have to go to my boring day job but thank you so much. Youre a smart guy no doubt.

That module does not look like a simple PWM driver. Is the motor connected directly to that board? If so, how many wires of what sizes?

This project is beyond my expertise.

Bob

Yes it directly connected on the output from the board, they very small maybe 14g-16g

 

How many wires? 14ga is good for 15A, so that would make sense.

Bob

 

How many wires? 14ga is good for 15A, so that would make sense.

Bob

Just 2 positive and negative

 

Here Ya go ........
I hope this isn't more complex than You were expecting.
Let me know anything You don't understand about it.
.
.
.
View attachment 265439

I do have 1 question what is the purpose of having the twisted wires going to the fuel pumps also the purpose of the rf chokes, I understand the chokes eliminate an ac current but is there a reason it would be an issue? Thank you

 

Here Ya go ........
I hope this isn't more complex than You were expecting.
Let me know anything You don't understand about it.
.
.
.
View attachment 265439

Also on the ignition switched power where the amp fuse is, whats the purpose of having the 1uf capacitor there? Wont leakage render the capacitor uses in a few days anyways? I don't know how to read capacitor specs that well so not sure. Thank you!

 

Hi danny,
Read these two links.
E

https://learn.sparkfun.com/tutorials/capacitors/application-examples

https://en.wikipedia.org/wiki/Twisted_pair

 

Hi danny,
Read these two links.
E

https://learn.sparkfun.com/tutorials/capacitors/application-examples

https://en.wikipedia.org/wiki/Twisted_pair

thank you!

 

Hi danny,
Switching high level currents thru long wires generates electrical interference which may cause the surrounding circuits, which pick up this radiation, to malfunction.
The chokes and twisted pairs help reduce this radiated electrical noise.
E

 

thank you!

Okay I understand the capacitor purpose now, I guess I didn't entirely grasp the idea of getting voltage dropout on a constant circuit but I thing more importantly the idea of filtering out voltage variations. I understand the idea of twisting together the wires now but I still view it as unnecessary as these arent sensitive components the signal they receive doesn't matter that much id assume the only twisted wires you typically see on vehicles are the can bus lines as their information they carry is very important and noise can cause many issues. Subarus use shielded wire that's grounded to protect their cam sensor signals.

 

hi danny,
A designer has a responsibility to minimize electrical noise radiation from his circuitry, as radiated noise can affect other sensitive circuits in the proximity, not just yours.

There are statuary regulations in force that state that equipment circuitry has to meet in order to gain approval.

E

One example of the long list of EMI regs.
https://en.wikipedia.org/wiki/List_of_common_EMC_test_standards

 

Brushed-Motors can sometimes generate a tremendous amount of RFI, ( Radio-Frequency-Interference ).
This RFI can be 3 to 4 times the normal operating Voltage, possibly more,
only Ceramic-Capacitors and/or Chokes can stop it,
it's a far higher Frequency than Diodes can deal with easily,
and it can notoriously smoke sensitive Electronic-Parts,
both in the Circuit in question, or anything nearby that may be sensitive.
( ask me how I know )

I had this particular problem with a ~30-Amp Blower-Motor,
and I've got a big pile of smoked FETs to prove it.
The FETs were rated ~50-Volts and ~75-Amps,
genuine International-Rectifier brand,
and on a 15-Volt project.
The FETs never even got warm to the touch, they were on a huge Heat-Sink.
And then, with everything working perfectly,
from out of nowhere, and without warning,
a pile of dead FETs.

They were smoked by high-Voltage RFI-Spikes from the Motor-Brushes.

In trying to solve this problem, I discovered this Forum, quite a few years ago now.
Capacitors and "Common-Mode-Choke" Cores solved the problem nicely.

The only way to tell if You might experience the same fate as I did,
is to try it without Filtering and see if anything smokes.
It depends a lot on the Motor design.
Lots of Filtering is simply good insurance.
That's also why Super-Fast-Diodes are specified as "Free-Wheeling-Diodes" across the Motor-Terminals,
they are also there to increase the efficiency of the Motors.

The Stock BMW Controllers may be failing from the exact same problem, generated RFI hash.
.
.
.

 

Brushed-Motors can sometimes generate a tremendous amount of RFI, ( Radio-Frequency-Interference ).
This RFI can be 3 to 4 times the normal operating Voltage, possibly more,
only Ceramic-Capacitors and/or Chokes can stop it,
it's a far higher Frequency than Diodes can deal with easily,
and it can notoriously smoke sensitive Electronic-Parts,
both in the Circuit in question, or anything nearby that may be sensitive.
( ask me how I know )

I had this particular problem with a ~30-Amp Blower-Motor,
and I've got a big pile of smoked FETs to prove it.
The FETs were rated ~50-Volts and ~75-Amps,
genuine International-Rectifier brand,
and on a 15-Volt project.
The FETs never even got warm to the touch, they were on a huge Heat-Sink.
And then, with everything working perfectly,
from out of nowhere, and without warning,
a pile of dead FETs.

They were smoked by high-Voltage RFI-Spikes from the Motor-Brushes.

In trying to solve this problem, I discovered this Forum, quite a few years ago now.
Capacitors and "Common-Mode-Choke" Cores solved the problem nicely.

The only way to tell if You might experience the same fate as I did,
is to try it without Filtering and see if anything smokes.
It depends a lot on the Motor design.
Lots of Filtering is simply good insurance.
That's also why Super-Fast-Diodes are specified as "Free-Wheeling-Diodes" across the Motor-Terminals,
they are also there to increase the efficiency of the Motors.

The Stock BMW Controllers may be failing from the exact same problem, generated RFI hash.
.
.
.

Ohhh I gotcha now, it's not to protect the signal to the motor from noise it's to keep the MOSFET from toasting. Thank you for explaining

 

hi danny,
A designer has a responsibility to minimize electrical noise radiation from his circuitry, as radiated noise can affect other sensitive circuits in the proximity, not just yours.

There are statuary regulations in force that state that equipment circuitry has to meet in order to gain approval.

E

One example of the long list of EMI regs.
https://en.wikipedia.org/wiki/List_of_common_EMC_test_standards

I'll read up on it thank you!

hi danny,
A designer has a responsibility to minimize electrical noise radiation from his circuitry, as radiated noise can affect other sensitive circuits in the proximity, not just yours.

There are statuary regulations in force that state that equipment circuitry has to meet in order to gain approval.

E

One example of the long list of EMI regs.
https://en.wikipedia.org/wiki/List_of_common_EMC_test_standards

I'll read up on it thank you