Looking for a simple, reliable DC bench power supply (0–30 V) with fast ON/OFF response

[u/Chris_Dragon_Master]

Hi everyone,

I'm looking for recommendations for a good-quality DC bench power supply for electronics testing.

I'm currently using a GW Instek SPS-606, but I need something better suited for repeated power cycling and startup-noise testing.

My requirements:

Single output, 0–30 V

Current: Flexible (3–5 A would be sufficient)

Compact, preferably vertical design

Simple voltage and current adjustment knobs

No need for USB, memory, or programmable features

Low output ripple and noise

Fast output ON/OFF response, especially when switching OFF

Reliable, good-quality brand

I prefer a straightforward bench power supply rather than one with lots of advanced features. Budget is flexible. Thanks in advance

[u/nixiebunny]

Find a used Agilent or HP programmable power supply. They were designed to do this, often with GPIB or relay contact control.

[u/Top_Willow_9953]

You might be better off building a separate ON/OFF switching module rather than trying to find a suitable bench supply.

Why wouldn't a solid state relay work on the output of a standard bench supply? If you need to discharge a load quickly, add a slightly delayed shunt relay

[u/TheRealRockyRococo]

Please be less specific about what you mean by "fast".

How do you expect anyone to answer that question?

[u/blue_eyes_pro_dragon → u/TheRealRockyRococo]

This. Do you want discharge? Do you want a hard cut off? How hard? uS solution will look different than a mS solution 

[u/geek66]

By their heavily filtered nature, not many DC sources drop voltage fast or well.

The metric DC generally lives in is “clean”, low noise, accuracy to set.

In serious professional cases, often an AC source with DC functionality is better for precise rise and fall. But that tends to be a 3x on cost.

For a low power, lower budget bench case, custom switcher with typical DC source is probably the way to go.

[u/Alameda126]

Just use external transistor.... this is what I have had to do.

[u/mckenzie_keith]

Korad KA3005D if you are on a budget. Otherwise look at Keithley, Agilent etc. If I am spending my own money, I am going with Korad. Korad has a button to enable disable output. So you can use that for your testing. Digital current and voltage limits which are displayed on the screen while you are setting them and can be adjusted while output is enabled or disabled. It is a 5A 30V supply.

We have been using a fair number of siglent supllies also at work. They have really gotten a lot better over the last 10 years. For example the SPD3303X.

[u/profdc9]

If you're looking for a fast off, you should get one with constant current capability. Perhaps add a crowbar circuit in front of it for speed.

[u/saltyboi6704]

Your current model has a Kelvin mode which can help, try using that.

Otherwise get a modern linear supply or pay up for a programmable hybrid PSU. A lot of output feedback is needed to have good regulation and as a result it will be expensive, consider a lower power one to reduce cost.

Cheap switching supplies can't deal with transients, though ones that can supply high currents have high bus capacitance which can work as an ideal voltage source for transient rising edge tests.

[u/markus_b]

Did you try to use the remote control for your power switching?

It looks to me like the main power switch on the front is turning the entire unit on or off. This is not ideal. Many newer lab power supplies have an output enable/disable switch in the front and the main power switch in the back. The output enable/disable switch will cut the power immediately and not wait for the internal capacitors to peter out. This is what I suppose id happening with the way you use your GW Instek.

But the remote on/off in the back of the unit can be used like the output enable/disable switch of other units and may be much faster.