PIC10F322 Sleep Current Challenge

[nickelflippr]

Hey, I'm checking in to see if anyone has some ideas on my high PIC10F322 sleep current. In the past I've never had a problem getting sleep current down to a reasonable level of <30ua or much lower depending on the chip.

The app is running from a single 3.7V li-ion cell. And after going to sleep it is still reading 400ua! Some pertinent info, sorry no schematic.

CONFIG: OSC= INTOSC, BOREN = OFF, PWRTE = OFF, MCLRE= OFF, WDTEN = OFF, LVP = OFF
OSCCON set to 4Mhz
RA3 is being used a button input with a 10k pulldown resistor and bypassed with a 0.1 uf cap.
RA0 is being used as a PWM1 output.
RA1 and RA2 are unused and in a digital output state.
VREGCON,VREGPM1 bit is SET so it will be in low power mode during sleep

With the amount of current being used I'm thinking either the OSC is still trying to run at a high speed, or the internal voltage regulator is being used?

Tried setting OSCCON to LPINTOSC prior to sleep, no luck.

Also hooked up a lower battery at < 3.0V thinking the internal regulator would have no reason to regulate. No luck with that either, though the sleep current went down to 300ua.

I haven't worked with the 10f322 too much, so must be overlooking something obvious.

 

[Joe G]

when I put my pic to "sleep", I clear everything that isn't being used, is your pwm still on? Have you read micrchips DS01146B chapter 2, has some useful power saving ideas.

 

[nickelflippr]

Cleared the PWM1CON and PORTA registers and still the same high current. Reread tip's and tricks chapter 2, but didn't see anything there that could help. Thanks for reminding me though, it's a great little book for refreshing the old gray cells.

SOLVED:
This was really bugging me, so I plopped a dip package in a breadboard and fired it up and back down to 29ua....

The board I was using was the little PIC10F322 demo board. I have done a lot of monkeying around with it in the proto area, smoked a pin on the micro and replaced it, and so on. So, I will chalk it up to parasitic's someplace on the board.

The 10f322 power down current draw is around 10X that of say a 10f222. There is a price to pay for all the extra peripherals and functionality.

 

[Joe G]

I'd be REALLY happy w/ a sub 1ma sleep, I could only get my latest project down to just over 1ma. Reading your post made me reread that tips and tricks also and recheck
my own code...

 

[3v0]

It looks like they are talking about chapter 2 in
https://ww1.microchip.com/downloads/en/devicedoc/01146b_chapter%202.pdf

 

[nickelflippr]

I'd be REALLY happy w/ a sub 1ma sleep, I could only get my latest project down to just over 1ma. Reading your post made me reread that tips and tricks also and recheck
my own code...

Aside from clearing the outputs like you mentioned, pulling floating inputs up or down is another one to look at. Also, any voltage dividers or voltage references can be run off the micro pin while awake. There was post awhile back where a fet was used to switch a peripheral IC ground off, it all adds up. Switching off the FVR (fixed voltage reference) was worth 37ua on the 10f322. All the PIC clock and peripheral loads are spelled out in the Electrical Specifications/DC Characteristics chapter of the data sheet.

I would like to try for na sleep current on one of the XLP (extra low power) devices if the project presents itself.

@3VO sorry about that

 

[Joe G]

my latest project has been a solar tracker for my anemometer, My goal is to use less then 20ma. lol. I almost got it, just finishing it up the coding today I hope, finding a
motor to run under that at 2.5 volts max was a tough one though.