voltage regulator vs LDO

[jordan76]

Hi guys,

Sometimes we need to generate an internal power using external power.
I know two options:
No 1. Generate a banggap reference first, then amplify to the volatge level as needed and buffer to the specific circuit
No 2. LDO

What are the cons and pros of these two methods? Any other good approaches to achieve same goal?

Any inputs/comments are welcomed. Thanks.

regards,
jordan76

 

[flatulent]

No. 2 is the cheapest way. No. 1 will have the lowest ripple output if you design it properly. It all depends on your circuit needs.

 

[Fom]

In really you mentioned only one option, because LDO = Voltage reference (usually bandgap) + Amplifier. So if do that in IC design both of this options are absolutely the same. If you mean PCB design see previous post.

 

[Sprint Zagato]

LDO IC is so cheap.
Using discrete components to make the same function as LDO serves only wasting PCB space and sometimes money also.

 

[frankon_o2]

I think the two options are same, LDO is the voltage regulator, why we call it LDO is because it can work under very low drop out conditions, then the heat and wasted power on LDO can be reduced. If we use it with high drop out voltage, it also work well, also it can be called voltage regulator.

 

[nicleo]

Just posted some useful links at **broken link removed**. Hope this will help.

 

[jordan76]

Thanks for your replies!

In my opinion, No.1 option may be different from LDO in their circuit architecture.
LDO is usually a pass gate(PMOS for CMOS) with a resistor-divider feedback applied to an error amplifier while No.1 option consists of at least three stages including bandgap, linear opamp and voltage buffer.

That raised another question about voltage regulator: what circuit architecture do you think is better for use in practice? or better for what application? Thanks.

regards,
jordan76