Tool/software:
I'll use a 12VDC main supply with on-board supplies running off that. The supply design requirements are:
|
Supply |
Measured Current |
Design Current - Includes large margins for possible requirement changes |
|
+5.0VDC |
149mA |
500mA |
|
+3.3VDC |
88mA |
300mA |
|
+1.8VDC |
< 10mA |
50mA |
|
-5.0VDC |
-1.54mA |
-25mA |
|
-12.0VDC |
-1mA |
-25mA |
Options?
- Individual switchers running off the +12VDC main
- Switcher from 12VDC to +5VDC and +3.3VDC, with LDO’s
- Off the +5V to generate a linear +3.3V, but that’s ~0.51W generated and wasted, worst-case
- Off the +5V or +3.3V switchers to generate the +1.8V. Not much in the way of heat but still an efficiency hit.
- Negative voltages could be
- Inverting switchers or grounded-output positive switchers
- Switched capacitor voltage inverters
- Just not as highly regulated unless I run through LDO negative linear regulators, but the efficiency would be lower.
The goals are
- To be able to handle these requirements
- Small board area
- Reasonable efficiency – any heat generated is received by the adjacent measurement boards
- Generating low heat
- Able to go to near zero load current without oscillations
- Able to provide the margined current levels noted above just in case … of whatever.
Do you guys have any “new-and-exciting” multiple-output ICs that would do the job, off the shelf recommendations, or combinations?
Any and all suggestions gratefully accepted. 
Thanks!
