dc-dc power supply used on Azul

Alessandruino's picture

Thanks Harland !!! So this is

Thanks Harland !!! So this is definitely enough to power the whole InMoov??

Or you would go with 3 voltage regulators?

The heatsink gets hot?

harland's picture

heat sink

As you can see heat sink is big. It gets warm but have not seen it hot. I think I hooked it up Sat. and it has been on all week, but Azul has not been used much. I leave it on for Greg to work and test the software on a working inmoov. The TI manual shows 3 in parallel for 15 amps. I just decided to go with 2. The meter that shows up on the ip camera is showing the 6.5 volts from the dc-dc supply. It does not drop much (6.3v) when rasing both arms which should use a lot of current. Who knows what we will need when Gael get working legs?

kwatters's picture

parallel vs series

Awesome!  Thanks for sharing this!   It looks likie this circuit is basically running two LM338's in parallel to generate a total of 10 amps when each individual lm338 is only rated for 5amps each.  They are both driven by the same control resistance, so the output (if the devices are truly identical) should be the same.

I'm sure some natural varience in fabriation will favor one vs. the other in this design, but this design is really nice because it splits the amperage across multipel LM338's.  

I have been estimating power consumption based on the max amperage per servo/devices, so if you have 1 servo, figure on 1 amp (coudl be more at peak operation).  The full inmoov is 20+ servos (depending on how far along in the build you are.  So, you might want to extend this circuit with 2-3 more LM388's to cover the full load to the servos you want to drive.