Regulator LDO Low Drop-Out for high Currents

This regulator is straight forward.
Uses the OPA1655 to control 3 transistors.
It is a low drop-out regulator.
In my image you can see an example for 20.30V in and 20.00V out at load 2.5A.

I have simulated to see the PSRR.
At 100Hz it is better than 121dB. At 1kHz it is better than 93dB.
The PSRR is mainly determined by the Opamp OPA1655.

The regulator is adjustable from 10V out to 30V out.
Of course this is limited by the max supply to the opamp: 40V.

Regulator Only_20.jpg
 
Food for thought:
It always scares me when there is no current limiting, as repair is very costly to repair.

Adding emitter resistors to U3 & U5 will greatly help reduce current hogging. It also gives an opportunity to add current limiting circuity.

Adding local bypass to U2, and a reverse diode for inductive loads should be needed.

Boot Strapping the power supply to the Opamp can make it run @ higher voltage.
 
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