Various configuration of linear regulator for parallel operation discussed in this technical article from Analog Devices. Linear regulators provide a simple, low noise solution for dc-dc regulation. However, at higher VIN-VOUT differentials the low efficiency and high power dissipation of linear regulators limits the amount of output current that can realistically be delivered.
Connecting multiple linear regulators in parallel spreads the load and the heat over several ICs, increasing the useful range of output currents a solution can deliver. However, connecting linear regulators in parallel is not always straightforward. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies.
Feel free to reach him for feedback, random tips or just to say hello Let's look at the LT At full load and over temperature, The LT's output voltage ranges from 3. When paralleling devices, If one LDO output is at the upper value and the other is at the lower value, the paralleled LDOs will not share current; the one with the higher output voltage dominates over the entire load current range.
To improve current sharing capability, identical balancing resistors can be added at the output of each regulator as shown in the figure below, but for tight matching i. For example, when paralleling two 3.
Once it supplies an additional mA, the additional drop across the balancing resistor causes the two output voltages to match and the LDOs will share current. However, the voltage drop across the current balancing resistors is much too large at full load 1. One can add current sensing circuitry current sense resistors and an amplifier at the input or output or on current limiting pins if the amplifier has this feature to balance the currents and maintain proper output voltage, but the external circuitry adds cost and requires additional board space.
A feedback loop is used to match the two current limits by adjusting the output voltage of one of the amplifiers. As with the previous example, an external amplifier and current setting resistors are required for operation. The LT is an example of a linear regulator solves this problem in a very simple, unique way. The LT is a 1. The devices are easy to parallel and share current very well.
Connect and share knowledge within a single location that is structured and easy to search. I need a 12V 2. I happened to have 2x 2A 12V linear regulators I brought and did nothing with. I was wondering could I wire them together and get 12V 4A or would I have divide my circuit amongst the two regulators? A schematic of how I would wire them would be much appriciated. It all depends on the regulator, and how "balanced" the two should be.
The normal method is to simply run the output of the two regulators through a diode one each , and then connect the outputs of the diodes together. The diodes are there mainly to isolate one regulator from the other.
While simple, this method doesn't always work well. First, you have the voltage drop of the diodes to contend with. And second, the regulators are not well balanced. As the load increases, the balancing gets better but it's never perfect. Because of this balancing issue, the max load is not quite double what one regulator can do.
The better method is called "active load balancing". It still uses the OR-ing diodes, but this time a small circuit dynamically adjusts the output voltage of the regulators to keep the load balanced. And thus, the max current can be double what any one regulator can achieve by itself.
Doing this kind of circuit is tricky and challenging, but not beyond an experienced hobbyist. A third method requires the use of regulators with an isolated output. In this case, you set up the regulators to provide all the current, but half the voltage 6v 2. Then wire the regulators in series to give you the proper voltage.
Of course, this isn't appropriate for every situation. The fourth method is simple. Just wire up the two regulators in parallel.
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