Class D amplifier as four quadrant Power Supply - Stupid idea?

[ulwur]

Hi! I have searched the forum for a topic like this but haven't found anything useful.

 I have an idea.. Trying to design a 4-quadrant power supply for my bench, and got the idea to use a Class-D amplifier circuit for the output stage to minimize the losses.

Is this a good idea? Will it work? Have it been tried?

Most of the time the supply will, ofcource, be working like a simple Buck voltage regulator.
Ideas on how to create the PWM waveform? The resolution of the PWM would have to be something like 6000 steps to create +-30 volts with 10 mv resolution. The input to the PWM Circuit is analog so I cant use a Micro to create the PWM signal.

Is it too complicated? Am I Better off with a traditional Class AB amp with switching buck pre-regulators to keep the losses manageable?

[bitseeker]

A four-quadrant power supply is able to sink as well as source power. In other words, it's both a power supply and an electronic load, depending on which quadrant it's operating in. So, you'll need to understand how both types of equipment work.

A Class-D amplifier is a switch-mode power supply (SMPS). Search for that and you'll find lots of information. Note that they are more complex than linear power supplies.

[NiHaoMike]

Amplifiers generally are designed to supply predictable loads, not wildly varying ones.

[David Hess]

A bipolar (positive and negative, not transistor type) output class-D amplifier can make a great output stage for a 4 quadrant power supply with the usual caveats about noise and stability.  Higher power units do exactly this when high power density is required.

Just beware that when operating as a load, the power is transferred to the internal power supply which may rise out of bounds if not controlled.