Split one DC supply into 4 independent DC supplies

Question

I want to take one DC source from a Rigol 832 and split that output into 4 adjustable, independent DC outputs that I can connect in series.

Is this possible? The goal is to make a circuit that will emulate a 4S battery pack where I can adjust each independent output individually.

Provide some sort of spec in your question. What voltage range? what current range? — Jack Creasey, Commented Nov 26, 2021 at 23:04
Voltage range per cell is 2V - 4V. Total series voltage 8V - 16V. The current requirement should be low. This is only to provide voltage feedback through the BMS balance wires to a microcontroller on an LiFePO4 BMS, to power the BMS microcontroller and it's 2 status led's. The balance wires go through voltage dividers then to the adc input pins on the MC. I would estimate under 100mA. It's not my intent to load the circuit just to simulate cell voltage feedback to the MC and monitor the MC's output pins during various cell balance scenarios. — cubflier, Commented Nov 27, 2021 at 0:58

Jasen Слава Україні · Accepted Answer · 2021-11-26 21:12:07Z

3

4 shunt regulators connected in series.

schematic

^{simulate this circuit – Schematic created using CircuitLab}

depending on what to need to do with the outputs you may need something stronger than a TL431

eg: figure 21 from the TL431 datasgheet

schematic

answered Nov 26, 2021 at 20:53

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\$\begingroup\$ The desired voltage of the 4 outputs range is 2V-4V. TL431 Vref is 2.5. Is this output range workable with the TL431? \$\endgroup\$
– cubflier
Commented Nov 26, 2021 at 21:38
\$\begingroup\$ use TLV431 (which has a 1.24V vref and goes up to 6V ) instead then \$\endgroup\$
– Jasen Слава Україні
Commented Nov 26, 2021 at 21:39
\$\begingroup\$ The real disadvantage here is that the battery emulator is drawing a constant power from the power supply (whatever series limit you set) and has absolutely no pulse capability. Once you hit the current limit the voltage will begin to collapse and you have no control of the individual 'cell' voltage. \$\endgroup\$
– Jack Creasey
Commented Nov 26, 2021 at 22:43
\$\begingroup\$ capacitors could be added to improve pulse capability this is probably worth doing. efficiency could be improved by sensing the current through each shunt regulator and feeding that back to the current source to maintain only a minimum current through each regulator. but that seems like extra complexity for little gain. \$\endgroup\$
– Jasen Слава Україні
Commented Nov 26, 2021 at 23:12

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jp314 · Accepted Answer · 2021-11-26 20:56:43Z

-1

No, you can't do this with a power supply without adding many external circuits.

You could use the 30 V output to emulate the 4 cells, but you can't easily emulate the tap points between the cells.

answered Nov 26, 2021 at 20:56

jp314

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\$\begingroup\$ I do expect to add external components. Trying to get some idea of what that circuit involves. \$\endgroup\$
– cubflier
Commented Nov 26, 2021 at 21:31

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