Hot!PIC24FJ128GA306 sleep mode current: 16+ mA current consumption

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PKaban
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2016/03/31 01:51:37 (permalink)
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Hi,
 
I've borrowed the code you have posted and ran it on GA306-I/MR (year 15, week 13), powered from NCP583XV30 with 22 uF polarized output cap. Current is ok (several microamps). Our board does have odd capacitor on VCAP (10 uF tantalum), but 1.8 V looks pretty good (with 10 mV, 40 kHz noise).
 
I take it that SPX-based power supply is equivalent to power supply of you previous, 24FJ256GB110 design, and previous designed was powered by 3.0 V, too? If so, there is little point in trying different power options (like wiring VDD directly from battery, or maybe from another board with different supply). Still, might give it a try.
 
Aside from trying different caps for VCAP while checking it and VDD with a scope, there is little I can suggest. Hope Microchip finds something.
post edited by PKaban - 2016/03/31 01:58:01
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dwalkes
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2016/03/31 06:53:07 (permalink)
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Thanks for testing this!
PKaban
I take it that SPX-based power supply is equivalent to power supply of you previous, 24FJ256GB110 design, and previous designed was powered by 3.0 V, too?

It used a fixed voltage regulator, also at 3.0V.  I haven't tried swapping power supplies with that one yet but it might be interesting to try.
PKaban
Aside from trying different caps for VCAP while checking it and VDD with a scope, there is little I can suggest. Hope Microchip finds something.

Me too.  I think we are going to wait to see if Microchip has any direction for us.  My first inclination is to try to reproduce on the LCD explorer board by changing the power supply voltage configuration.  Thanks for your help.
 
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dwalkes
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2017/06/27 20:22:28 (permalink)
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Hi,
For anyone who was following this - the problem was actually a x2 error in the layout related to the reset monitor, which was one of the few components I didn't cut out of the board thinking it couldn't cause this problem :).
 
The wrong part number was specified which resulted in an unexpected trip point of 3.0 V instead of 2.6.
 
In addition, the pinout was also wrong in the layout and the output pin was connected to VDD, meaning when the 3.0 trip point happened it attempted to short itself to ground!
 
DOH!
 
Thanks for your help and comments.
#23
Nikolay_Po
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2017/06/28 07:06:09 (permalink)
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Thanks for resume. One time I had to solder the chip by bare copper on the fly with bypassing capacitors right on the pins then washed it by a solvent to investigate the consumption problem.
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Charles Lo
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2017/12/06 15:00:54 (permalink)
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Hi dewalkes and others discussing about the problem of large current consumption in sleep mode,
 
I used the explorer16 with the pic24fj128ga010 chip and got the same problem recently.
In normal mode with a 8 Mhz clock operating, current consumption by the explorer16 was 19 mA.  In sleep mode, current consumption reduced to 13 Mhz, indicating the shutting down of the clock saved 6 mA which is consistent with what is stated in the datasheet.
As the scenario appeared to indicate that something in the explorer16 board was drawing the significant large current, probably not due to the pic24fj128ga010 chip itself, I  took out the chip (in a PIM package) from the explorer16 board and connected separate power, the primary crystal and the secondary crystal and run the same sleep mode program again.   With that test, the processor in sleep mode draw was only 0.14 mA (140 uA) which is consistent with what the datasheet states bearing in mind that small amount of current was still needed to power the primary and secondary oscillators.   I changed the power supply voltage from 3.3V to 3.0V, simulating what you mentioned to be the source of problem, now current draw became 0.18 mA which was larger but still was a reasonable figure.  
Your past finding of the reason due to 3.0V power supply (instead of 3.3V) does not appear to make reasonable sense to me and my test was not able to validate that.   I suspect that your problem of excessive current during sleep mode being solved was not due to the power supply voltage difference, but because of the fact that you cut all the IO pins and unnecessary connections in the development board which was equivalent to connecting the processor out from the development board as I just did.  There may be a possibility that you thought that it was the power supply voltage change solved the problem but in fact, it was the other thing (cutting other unnecessary connections to other devices) that solved the problem.    
My test and my solution shows that as the development board needs to power many accessories such as the USB port etc., it always draws significant large current even with the processor being put into sleep mode. After one's C program is being development board and with the processor being connected independently away from the development board, the problem will be solved. 
I hope that my experience of solving this problem will be of help to anyone encountering similar problem.  
 
 
 
#25
qɥb
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2017/12/06 15:09:31 (permalink)
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I assume you only read page 1, and didn't see the explanation in post#23

PicForum "it just works"
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Charles Lo
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Re: PIC24FJ128GA306 sleep mode current: 16+ mA current consumption 2017/12/07 14:24:19 (permalink)
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Hi qyb,
 
Thank you for your reminder.
Yes, you are right, post 23 did clarify that the problem was due to a faulty circuit connection. 
#27
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