HACKED! : Adding a Current Limit Feature to a Buck/Boost Converter
video description
I have 2 different two solar panel 1 panel with 60cell (V1) & the other one its 72 cell (V2) where they have not match VOC.
What i want is use LM2596HV base buck converter on V2 source panel and adding external a P mosfet and draw about 30amp where the output on buck converter is equal with V1 output and tie together with schotky blocking diode.
If V1 24 volt, output on buck converter (V2 input) will follow 24 volt.
If V1 27 volt output on buck is 27 too. So output oo V2 buck converter is depending on V1.
And i want its working in linear.
Can you show me an example circuit with schematic test.
Thanks. best regards.
Sorry for my bad english
Date: 2020-09-05
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Comments and reviews: 9
KidCe
I still don't understand how this switching regulator stuff works in the way of control theory I mean if it's just a too much or too low feedback, the regulator has to linear increase or decrease the duty cycle to sometime reach the desired voltage. Wouldn't it be smarter to use a proportional Feedback P-Regulator so the Regulator would know how much the dutycyclr has to be adjusted? Or maybe even better a PI oder PID.
I think this two state regulator / comparator princible should work good for constant loads, but if you have big current spikes or drops, I can't imagine that it can react fast enough to don't get overshoot or voltdrop
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I still don't understand how this switching regulator stuff works in the way of control theory I mean if it's just a too much or too low feedback, the regulator has to linear increase or decrease the duty cycle to sometime reach the desired voltage. Wouldn't it be smarter to use a proportional Feedback P-Regulator so the Regulator would know how much the dutycyclr has to be adjusted? Or maybe even better a PI oder PID.
I think this two state regulator / comparator princible should work good for constant loads, but if you have big current spikes or drops, I can't imagine that it can react fast enough to don't get overshoot or voltdrop
reply
SonicWawes
An engineer here.
Hi Scott, can you please look at your video once again? I believe you have an error in your schematic in 5: 50 when you are showing the circuit of differential amplifier for the current measurement. The R3 100 K shall be connected from non inverting input of IC1A to GND, not in series with the input. When it is grounded it will not work and output voltage from IC1A will be only close to zero volt. You are showing the same circuit couple more times in your video so it might be good to review it for all the audience.
Keep going with your videos.
reply
An engineer here.
Hi Scott, can you please look at your video once again? I believe you have an error in your schematic in 5: 50 when you are showing the circuit of differential amplifier for the current measurement. The R3 100 K shall be connected from non inverting input of IC1A to GND, not in series with the input. When it is grounded it will not work and output voltage from IC1A will be only close to zero volt. You are showing the same circuit couple more times in your video so it might be good to review it for all the audience.
Keep going with your videos.
reply
Blondie
Great video. There was a lot more than I expected to add current limitation to these bucks.
Very cool though.
But I guess with all that's involved, after all is said and done, it's probably better to just buy the ones that have both V and C pots on them.
Thing is, they are a lot more expensive that the single pot ones.
Your engineering abilities are impressive.
You are a much better teacher than some I've experienced in my life. LOL
reply
Great video. There was a lot more than I expected to add current limitation to these bucks.
Very cool though.
But I guess with all that's involved, after all is said and done, it's probably better to just buy the ones that have both V and C pots on them.
Thing is, they are a lot more expensive that the single pot ones.
Your engineering abilities are impressive.
You are a much better teacher than some I've experienced in my life. LOL
reply
Chris
My big problem with all the current limit devices I've seen, whether built in or add on devices, is that they always perform the current detection on the ground side. While I understand why it is done this way, it simply isn't going to work where both the supply and the load have a common ground. I need a circuit which will measure the current on the high side or some other point in the device.
reply
My big problem with all the current limit devices I've seen, whether built in or add on devices, is that they always perform the current detection on the ground side. While I understand why it is done this way, it simply isn't going to work where both the supply and the load have a common ground. I need a circuit which will measure the current on the high side or some other point in the device.
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Epi
The issue I have with differential amplifiers for current sense is that they are very sensitive to errors in the resistor values. A 1% resistor error will give an output error of 1% of the _supply voltage, _ which is comparable to the thing you're trying to measure.
Alternative is to use a current sense amplifier. Silicon Labs SI8540-B-FWR is just one example.
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The issue I have with differential amplifiers for current sense is that they are very sensitive to errors in the resistor values. A 1% resistor error will give an output error of 1% of the _supply voltage, _ which is comparable to the thing you're trying to measure.
Alternative is to use a current sense amplifier. Silicon Labs SI8540-B-FWR is just one example.
reply
Daniel
Hey, could you actually convert that boost board to a buck board? ive seen that they are basically identic from the layout part of things. im wondering because i cant find a shematic for a buck only module to compare them both. thing is i ordered a couple and didnt look at the function saying boost but i need a buck lol.
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Hey, could you actually convert that boost board to a buck board? ive seen that they are basically identic from the layout part of things. im wondering because i cant find a shematic for a buck only module to compare them both. thing is i ordered a couple and didnt look at the function saying boost but i need a buck lol.
reply
education
Very good video, I have been trying to look for a boost converter that will take a single 18650 Li Ion Cell and boost its voltage from 4. 12 Volts to 30 volts. Most of the boost converter go with a min voltage of 5 volts. Is there such a boost converter or could one be made?
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Very good video, I have been trying to look for a boost converter that will take a single 18650 Li Ion Cell and boost its voltage from 4. 12 Volts to 30 volts. Most of the boost converter go with a min voltage of 5 volts. Is there such a boost converter or could one be made?
reply
Alireza
I build it with lm358 with a little bit of modification. i lower the gain so i can get up to two amps out of that. but the issue is a high frequency pitch sound from the circuit can u help me with that please? Boost converter madule is based on xl6009e ic
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I build it with lm358 with a little bit of modification. i lower the gain so i can get up to two amps out of that. but the issue is a high frequency pitch sound from the circuit can u help me with that please? Boost converter madule is based on xl6009e ic
reply
CHRYSOULA
Nice video. A small error thought at 6: 20, I think the diff. Ampl circui5 is not correct at the point where you have shown the ground. The non inverting input should be connected after the 3. 3k and then the 100k from the non inverting to ground?
reply
Nice video. A small error thought at 6: 20, I think the diff. Ampl circui5 is not correct at the point where you have shown the ground. The non inverting input should be connected after the 3. 3k and then the 100k from the non inverting to ground?
reply
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