Voltage Regulator - Powering a 3-Phase BLDC Motor and Propeller MCU from a 48V Source

entropy3

I am working on a project to control a 3-phase BLDC motor with a Propeller MCU. Up to this point I have been working with a power supply with two sources, giving me the luxury of powering my EEPROM/Propeller chip at one voltage and set another voltage for the motor.

Unfortunately, I won't be able to do this when I start operating from a 48V battery pack, which is my plan. Does anyone have any idea as to where to look for a voltage regulator that can handle this high voltage? I have both the 3.3 and 5V EM2937 voltage regulators sold by Parallax. It looks like these components are rated for transient voltages up to 60V, but I'm less clear on what kind of differential voltage they can manage (or should manage, for reliability) in continuous operation.

Can anyone point me to another voltage regulator suited for this application? Or should I be using some other DC-to-DC converter setup?

I'm new to both the Propeller platform and circuit design, so any comments from people with relevant experience would be greatly appreciated!

Thanks,

Leon

Have a look at the Nat Semi Simple Switchers:

http://www.national.com/en/power/index.html

Don M

Hi Jeremy,

Welcome to the forum! In one of my designs I use the National LM2674M-3.3 but that is only good to 40Vdc input. They have many others and their website makes it easy to design a power supply. Here's one I found that you might look at- http://www.national.com/ds/LM/LM2594.pdf It's good to 60Vdc and fixed at 3.3Vdc out @ 500mA. They have many others as well. Good luck! If you have any other questions please ask.

Don

Lawson

Dropping form 48V to 5-6V is a large drop. I've seen this solved by building a basic discrete transistor pre-regulator, but power loss can quickly get out of hand. Assuming just a Propeller at 80MHz (~75mA) the regulator would need to dissipate about 3.3 watts. A better option, in my mind, is to use a switching power supply. I'd look for a small pre-built module unless you want to learn how to build switching power supplies.

Digikey # 945-1062-ND or 945-1061-ND would work well. Digikey 445-3276-ND is isolated, and a bit cheaper. (this last one would also replace the 5v regulator unless it's output was trimmed higher than 5v) Anyway there are lots of options available if you search the catalog of your favorite electronics vendor.

Lawson

Zap-o

The simple solution is to use this regulator [ TL783CKCSE3 ] http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-20687-5-ND. It will tolerate up to 125Volts and regulate down to 1.25Volts.

2 resistors and a capacitor is all you'll need. Plus its in a To220 package so easy to breadboard and test.

Don M

The National device I mentioned in the above post is a switching device. Heat dissipation is not a problem. They are pretty efficient.

icepuck

These are drop in replacements for the 78xx regulators
http://www.dimensionengineering.com/SWADJHV.htm
-dan

Zap-o

@ icepuck

That is a nice drop in replacement but hell look at the price ^^ The one I listed should not get to hot useless a lot of current is needed and at ~ $2 its an affordable solution.

@Don
I do prefer switchers as well

ManAtWork

Hello Jeremy,

I use the LM5008 for that purpose. It can handle up to 100V input and 350mA load. An alternative part is the LM2594HV which can take up to 60V input and 500mA output. If you need more current, an LM2575HV would do. National has online design tools for all of them for free.