LPC1754 consumption

[lpcware]

Content originally posted in LPCWare by kocoedin on Mon May 12 01:59:05 MST 2014
Hello everybody,

im struggling with the same problem for 2 weeks now. Im using LPC1754 MCU to control a low power device. The MCU is having low power consumption (around 100uA) in Deep power down mode, which is ok for me. But i need to use the regular power down to wake up the device using GPIO interrupt. But in this mode the consumption is unreasonably high (25 mA). It is the same for deep sleep (25 mA) and sleep mode (27 mA). I have used the code from the application note from NXP and from KEIL evaluation board. I made sure no pins are draining current and at this point it seems as a software problem. Did anyone face a similar situation?

I would be grateful for some guidelines concerning this problem because i have exhausted all the solutions i could think of.

[lpcware]

Content originally posted in LPCWare by nxp_apps on Sat Jul 26 14:43:01 MST 2014
Hi,

The software I used is from the the application note I mentioned before....please try this.
Application note and software are all zipped into one folder.

Hope it works out.

Thanks.

nxp_support

[lpcware]

Content originally posted in LPCWare by mosi on Fri Jul 11 12:32:54 MST 2014
Hi nxp_apps,

could you please post your code?

We have a bare processor LPC 1768 programmed with the code from AN10915 going to deep sleep.
The power consumption is cca 2mA.
When removing 3.3V to GPIO, power drops to microamps.

When re-configuring pins to pull-down, power drops to 1.2 mA.

AN10915 states "Please note that in deep power-down mode, state of the port pins does not affect the current consumption and the steps mentioned above do not need to be considered in this mode." which is obviously not true in our case.

We have revision 'A' of 1768.

Thank you!

[lpcware]

Content originally posted in LPCWare by kocoedin on Sun May 18 13:09:57 MST 2014
Ok i guess i misunderstood it. I thought you meant the main oscillator XTAL. I made a custom PCB for my application. I managed to lower my consumption to 400 uA on deep power down. I have some other periphery that could be draining 200 uA at the most. Guess i need to look for more ways to reduce consumption to the specified value.

[lpcware]

Content originally posted in LPCWare by R2D2 on Sat May 17 07:43:18 MST 2014

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Quote: kocoedin
My application requires USB connectivity so it needs the oscillator.

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You need the Ethernet PHY oscillator to run your USB  :quest:  :O  :~

Not sure which hardware you are using, but usually LPC1754 does not support Ethernet, so probably you don't have an Ethernet PHY with oscillator. Should not cause problems if you solder it out  :)

[lpcware]

Content originally posted in LPCWare by kocoedin on Sat May 17 06:39:18 MST 2014
Thank you for the answer. I failed to notice to remove the oscillator. I will try it and see how it goes. I don't see why would you specify consumption's without the oscillator and how does it even influence it since its turned off. My application requires USB connectivity so it needs the oscillator.

Either way i will try it.

[lpcware]

Content originally posted in LPCWare by nxp_apps on Fri May 16 16:58:32 MST 2014
Hi,

As per the app note (http://www.lpcware.com/content/nxpfile/an10915-using-lpc1700-power-modes-0), I am able to replicate the numbers mentioned in the app note and LPC176x Keil eval board.
Are you running the software provided from the app note or have you modified it to run own your own board?

Also, as mentioned in the app note, was the 50 MHz oscillator de-soldered and removed from the board?

Thanks.

nxp_support