Propeller Mini board power

iseries

Looking at the spec sheet for the Propeller mini it stats a voltage of between 6.5Volts and 12Volts.

Ok, but then I look at the schematic for the unit and it states it's using a LM2904-5 voltage regulator and that regulator has a rating of 6.5Volts to 26Volts.

So why is it that the Propeller mini can only go to 12Volts?

Also I was doing a little power calculations since I was looking for a low power application and was curious as to what it took to power a Propeller Mini.
With a simple application that measure the joy stick position it uses about 29ma to run the application with two cogs.

For another application which is a weather station that uses 7 cogs the draw changes to 79ma to run the application. So each cog when used pushes the amount of current needed. So an application may be more efficient current wise if it did not use a cog to run the application.

Mike

kwinn

iseries wrote: »

Looking at the spec sheet for the Propeller mini it stats a voltage of between 6.5Volts and 12Volts.

Ok, but then I look at the schematic for the unit and it states it's using a LM2904-5 voltage regulator and that regulator has a rating of 6.5Volts to 26Volts.

So why is it that the Propeller mini can only go to 12Volts?

Also I was doing a little power calculations since I was looking for a low power application and was curious as to what it took to power a Propeller Mini.
With a simple application that measure the joy stick position it uses about 29ma to run the application with two cogs.

For another application which is a weather station that uses 7 cogs the draw changes to 79ma to run the application. So each cog when used pushes the amount of current needed. So an application may be more efficient current wise if it did not use a cog to run the application.

Mike

I'm guessing you meant LM2940-5, and that is a linear regulator which has to dissipate power equal to (Vin - 5V) x I. That may overheat the regulator at higher input voltages and currents. Also, the capacitors may not be rated for higher voltages.

Each cog uses power when it runs, but it is the cogs that execute code. If the tasks do not require high speeds then one cog may be all you need.

JasonDorie

Using the internal oscillator (or a lower value crystal) will reduce power consumption as well, and you can switch that on the fly. Using wait conditions (like waitcnt, waitpeq, waitpne) puts that cog in a low power mode too.

Someone on the forums did a bunch of testing to see how low they could push the Prop. I don't recall who it was, but a search of "micro power" or "low power" should turn up something.