POWER_DOWN_MODE consume too much power

[lpcware]

Content originally posted in LPCWare by pgr on Thu Feb 27 08:29:23 MST 2014
Hy everyones,

I am using a LPC1763 on a custom board. When sleeping using DEEP_POWER _DOWN, the board consume 80uA. According to the LPC1763 the consumption in this mode should be 0.6uA so the board consume approx 79.4uA. This value match my expectation, as the 80uA is approximately the sum of the quiescent current of the power stage and external wakeup logic.

I now I use POWER_DOWN_MODE I expect to have the same 79.6uA plus the 31uA from the chip (according to the datasheet).
But in this case I measure 243uA so I have 132uA more than expected. Do you have any idea why ? Should I disable other things ?

Note that in both case I have already disabled most peripherals and Brown-Out detector

Any hints would be really appreciated

[lpcware]

Content originally posted in LPCWare by pgr on Fri Feb 28 02:23:51 MST 2014
I could definitively not do what you suggest (the power pins are directly connected to a power plan).
For me the board consumption is around 80uA because this is the value I measure when in DEEP_POWER_DOWN mode. Then going to POWER_DOWN_MODE I expect to have only 31uA more according to the LPC176x datasheet.

So I think that there is a difference between the two mode that could influence the rest of the board consumption but I could not find what are the difference between the two mode...

Thanks for your help

[lpcware]

Content originally posted in LPCWare by rocketdawg on Thu Feb 27 09:09:24 MST 2014
modify one board by lifting all the Vcc pins to the CPU. (can't do that with a BGA package, but maybe you can cut traces)
then measure current.
most likely, it is not the CPU, but all the other circuitry.

you would really have to attach a schematic.