# Connecting multiple DC sources in parallel without the use of diodes

Obviously to have more current is there a way to somehow connect multiple DC sources together not by using trivial series Schottky diodes, but using mosfets and LDO(Low dropout) circuits? To somehow use the mosfet body diode forward voltage drop as a one way "valve" as long as it's within 0.5V or less between any 2 sources in the array? I don't think it's possible. But I'm not sure... That's why I'm posting this question. I don't think it's possible because the mosfet is not a unidirectional switch but bidirectional? I think the N or P channel is symmetrical in the manufacturing of mosfets. I'm not sure... I don't know. But if the substrate is connected to the source then it's not symmetrical...I'm not sure...I don't know...I have many questions and very few answers and self-confidence. I'm almost sure the circuit in the picture does not work, but can somehow be made to work? Can two mosfets in anti-series be used somehow? I don't know...I don't know anything. Can somebody help me?

• Connecting 2 batteries in series increases current. Apr 5, 2022 at 13:18

Actually when multiple dc sources have to be connected to increase the current, the problem is not as simple as it looks.

First, you have to look into the actual problem which stems from basic electrical principle, ie.,

• Different rating Voltage Sources should not be connected in parallel and Current sources should not be connected in series.
• What is acceptable is like this: One controlled voltage source fixing the parallel combination voltage and other sources behaving as current sources.

simulate this circuit – Schematic created using CircuitLab

• Droop control is usually employed in parallel combination of voltage sources.(You can check the literature for that). Most commonly, it is used in grid where multiple sources are connected.

So, the problem comes down to a basic one. We have to control the dc link using one source acting as voltage source and other sources to behave as current sources(if more than one acting as voltage source, control problem comes into the picture with possibility of circulating current).

This implies we would need, a voltage to current converter (Power electronic circuits have to be dealt with). Now this becomes a little complicated in which you will have to study up a bit on it. It is difficult to tell all the things here.

Following are the references you can read in which they implemented such a thing:

Unitrode IC Application Design

Many more available on internet.