Linear or switching regulator?

[Gergo]

For my microcontroller based system, I need regulated 5V from a 24VDC input supply. Should I design the power supply unit with a switching regulator, or is it fine if I just use a simple LDO, capable of accepting 24V input voltage? As I saw, its cheaper and less complicated circuitry. What do you think?

 

[kellys_eye]

Depends what you feel is acceptable 'losses' in the system.

For a simple LDO regulator and 5V drawing 3A you will have to drop 19V @ 3A in the regulator - a power loss (heat dissipation) of some 27 watts.......

A switching regulator might have 90% efficiency so losses would be only 2.7W

Sounds like a simple choice to me......

Equally, you usually only use LDO regulators when the input voltgae is close to the output voltage - it's probably irrelevant but that's what LDO regulators were designed for.

 

[Gergo]

Depends what you feel is acceptable 'losses' in the system.

For a simple LDO regulator and 5V drawing 3A you will have to drop 19V @ 3A in the regulator - a power loss (heat dissipation) of some 27 watts.......

A switching regulator might have 90% efficiency so losses would be only 2.7W

Sounds like a simple choice to me......

Equally, you usually only use LDO regulators when the input voltgae is close to the output voltage - it's probably irrelevant but that's what LDO regulators were designed for.

Sounds reasonable, thank you!

 

[BobK]

Well, it depends on the current. If you are using only 1mA, the wasted power is only 19mW , and a linear regulator is a no brainer. The changeover point is probably somewhwe in the region of 50mA, which results in 1W of loss, which can be handled by a TO220 case woth no heat sink.

Bob