Current limiting help.

[Mosaic]

I have a 36V supply rail with a Lead acid battery (12V) to charge/equalize.

I have certain constraints which are:
1) 36V ties to batt +ve
2) Low side current control
3) Low heat dissipation, which implies a switch mode method.

For this particular application I wish to achieve a 1 amp max/fixed current flow.

I have access to a TL494, 330 uH inductors, Schottky 3A rectifiers, and assorted P & Nfets of suitable size. These are fine to do a regular SMPS, but this is low side so I need some help with it.
Thanks.

PS: I am considering something like this:
https://electronics.stackexchange.c...est-way-to-go-from-analog-input-to-pwm-output

Placing a 1 ohm, 2W current sense in the Source to ground and tapping off that with a RC low pass
to feed the average current into the TL494 err. amp , and let that controlthe Dcycle of the FET. perhaps 25Khz freq or so.

 

[MCU88]

Phases of engineering: Write out an requirements and analysis document. Draw up your block diagram. Then consider the schematic with actual specific parts...

 

[Mosaic]

OMG dude....that's not particularly helpful. Just looking for advice to point me to the right approach.

 

[MCU88]

OMG dude....that's not particularly helpful. Just looking for advice to point me to the right approach.

My impression is that you need some clarity in your life for you to be able to succeed with your projects. You have made no attempts whatsoever. I see no schematic. I see no requirements an analysis documentation. You're not one of these guys that just sits there with an soldering iron are?

 

[Mosaic]

My impression is that you need some clarity in your life for you to be able to succeed with your projects. You have made no attempts whatsoever. I see no schematic. I see no requirements an analysis documentation. You're not one of these guys that just sits there with an soldering iron are?

I guess you didn't have a look at the schematic in the link I posted?
Anyway, to be succinct, if you can't contribute, don't post at all, it just clutters up the thread.

 

[ChrisP58]

A variation of the classic buck converter should work for you. The basic design is the same, you just need to move the components around a bit.

Drive the mosfet with whatever PWM controller you choose. The grounded resistor will provide current measurement for current mode control, as well as it's peak current will be directly proportional to the battery charge current. You will need to use a differential amp to measure the battery voltage and reference it to ground.

 

[Cicero]

Phases of engineering: Write out an requirements and analysis document. Draw up your block diagram. Then consider the schematic with actual specific parts...

My impression is that you need some clarity in your life for you to be able to succeed with your projects. You have made no attempts whatsoever. I see no schematic. I see no requirements an analysis documentation. You're not one of these guys that just sits there with an soldering iron are?

How about stop trolling here dude...smh