I was taught not to use voltage regulators when there is a large voltage drop between the source & output while drawing a large amount of current.
Are there any fancy ways to drop 12V down to 3.3V while allowing you to draw up to 1A of current, BESIDES using a switching regulator?

Using a voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?

 

Use a regulator IC, 1A is not a great deal to worry about ?
If concerned, drop it with a 6v zener first then the IC.

 

Are there any fancy ways to drop 12V down to 3.3V while allowing you to draw up to 1A of current, BESIDES using a switching regulator?

We use voltage regulators; linear or switching. When you have a large output to input voltage differential and high current, switching regulators are more appropriate.

Using a voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?

You question doesn't have a yes or no answer, but using resistors is usually the least effective way to reduce voltage. It only works if the load current is constant.

 

Here is an example of DC-DC buck on Amazon and Alie. It will not have the power loss of a LM7805 linear regulator.
I can find the schematic if you want to build one. It will buck 12V down to 3.3 at 2A just fine. (I know it said 3A but....) If you get it direct from China, it will cost less than the parts alone here.

 

There are a number of pre-regulator schemes that will split the power dissipation between two or more devices. This may get you where you want to be without using a switching regulator. I don't know why using a pre-built module would give you the willies however.

 

Are there any fancy ways to drop 12V down to 3.3V while allowing you to draw up to 1A of current, BESIDES using a switching regulator?

Not really. However, the power dissipation is less then 9 W, which the linear regulator chip should be able to handle easily with a moderate heatsink.

Using a voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?

Correct. If having all of the excess heat concentrated in the IC is a concern, consider placing a 4.7 ohm or 5.0 ohm, 10 W resistor in series between the 12 Vdc source and the regulator IC input. This will cut the IC power dissipation in half.

ak

 

Using a voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?

I have to disagree with some of the comments here. If you a linear regulator to drop 12v to 3v, 75% of the power will be converted to heat by the regulator. Adding series resistors or anything similar just spreads that 75% loss over more components.

A switching regulator on the other hand can have an efficiency of over 85% – power lost is less than 15%.

 

9W of dissipation will require a significant heat sink. I agree, use a switcher.

Bob

 

I have to disagree with some of the comments here. If you a linear regulator to drop 12v to 3v, 75% of the power will be converted to heat by the regulator.

Yup; that's kinda their thing.

Adding series resistors or anything similar just spreads that 75% loss over more components.

Yes, that is exactly my point. We are in perfect agreement.

I'm not saying it is the perfect or best solution, just that its one major drawback is mitigate-able. And given what we *don't* know about the TS skill set or application, it is a safe starting point.

We don't know the nature or noise-sensitivity of the load. And, little buck regulator modules on ebay look cute and cost next to nothing, but they are a royal pain to quiet down enough for an audio application. or video. or EKG monitor. or . . .

ak

 

Yes, that is exactly my point. We are in perfect agreement.

Not quite. There's a very important word missing. I don't mean to be pedantic, but that missing word is crucial.

Using a voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?

"Using a LINEAR voltage regulator is no different efficiency wise as using other linear ways of dropping voltage (like using resistors), right?"

As I explained, a switching regulator is entirely different.