27-08-2019, 10:53 AM
(This post was last modified: 27-08-2019, 10:57 AM by ppppenguin.)
Mike, I think you've discovereed that an apparently simple regulator isn't as easy as it might seem.
Is it worth asking the question about what you want the PSU for? Your proposed design is going to need a very hefty heatsink as well as all the other issues that you've had with 338 regulators. If I wanted a 5A PSU I'd be using a switchmode unless there was some very good reason not to.
You can buy good quality mains input switchmode PSUs. Both chassis mount boards and "lump in cord". Don't know if you need variable voltage which makes thing s a bit harder. For 5V at 5A there are low cost regulator modules such as: http://www.hobbytronics.co.uk/d24v50f5-5...-regulator haven't looked for other output voltages.
Incidentally it's probably not worth building your own switchmode regulator. I've designed with the original National "simple switcher" chips but would now always look to a packaged solution if possible. If I want several amps at low voltage and low disspation it's much easier to buy than make.
If you must have a linear reg, the also consider the LM1084, a more modern part that may be less expensive than a good 338.
PS: The LM1084 is udner £3 from RS: https://uk.rs-online.com/web/p/low-dropo...s/5339331/
Is it worth asking the question about what you want the PSU for? Your proposed design is going to need a very hefty heatsink as well as all the other issues that you've had with 338 regulators. If I wanted a 5A PSU I'd be using a switchmode unless there was some very good reason not to.
You can buy good quality mains input switchmode PSUs. Both chassis mount boards and "lump in cord". Don't know if you need variable voltage which makes thing s a bit harder. For 5V at 5A there are low cost regulator modules such as: http://www.hobbytronics.co.uk/d24v50f5-5...-regulator haven't looked for other output voltages.
Incidentally it's probably not worth building your own switchmode regulator. I've designed with the original National "simple switcher" chips but would now always look to a packaged solution if possible. If I want several amps at low voltage and low disspation it's much easier to buy than make.
If you must have a linear reg, the also consider the LM1084, a more modern part that may be less expensive than a good 338.
PS: The LM1084 is udner £3 from RS: https://uk.rs-online.com/web/p/low-dropo...s/5339331/
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
