Powering a LPC1343

[lpcware]

Content originally posted in LPCWare by JohnR on Sat Nov 27 06:44:07 MST 2010
Hi,

This question has come up before but I could not find a definitive answer.

I want to use the LPC-Link card with a LPC1343 board of our own design, which obviously will have its own 3.3v supply

The options for connecting the 3.3v supply from the LPC-Link card during programming the card seem to be:

1) Do not connect the 3.3v from the link card just use the on-board 3.3v to supply the 1343.

2) Connect the 3.3v from the link card and disconnect the on-board 3.3v during programming and later reconnect.

Silabs USB dongle boards use a dual diode (MMBD1404A) arrangement to allow either the 3.3v from the dongle or an external source on the PCB when is disconnected from the dongle to be used. Would this be preferable?

Thanks for any help,

John.

[lpcware]

Content originally posted in LPCWare by JohnR on Thu Dec 02 06:22:48 MST 2010
Hello NXP_Europe,

Thank you for your message.

I have not yet measured the current. When I was developing the application using the complete LPCXpresso board, I had 4 LEDs mounted on the PCB to show the upper 4 bits of a register - did not occur to me at the time to check the current consumption.

Now the LPC1343 is mounted on a separate board together with the associated analog electronics with only 2 LEDs to control but I will for interest's sake measure the current on the 3.3v supply.

JohnR

[lpcware]

Content originally posted in LPCWare by NXP_Europe on Wed Dec 01 15:13:47 MST 2010
Hello JohnR,

Did you measure how much current your application + LPCXpresso consumes?

You can measure what the current of the unconnected LPCXpresso is (may depend on the software) ... current = thought pin 1 and 2 (shortcut is takenout) ... connector J4 (LPC1343).

[lpcware]

Content originally posted in LPCWare by JohnR on Sun Nov 28 06:51:18 MST 2010
Thanks to you both - I will follow your advice.

JohnR

[lpcware]

Content originally posted in LPCWare by Ex-Zero on Sat Nov 27 13:18:05 MST 2010
For all my own boards (LPC11C14, LPC1343 & LPC1768) I don't use LPC-Link power supply.
I don't know how much current it could source, but I just don't want to damage it.
So my own small Debug connector only includes SWCLK, SWDIO, RESET & GND.

[lpcware]

Content originally posted in LPCWare by TheFallGuy on Sat Nov 27 08:39:49 MST 2010
Use your own power supply. The LPC-Link is very restrictive in the amount of power it can supply, as the power output is actually via the LPC3154's in-built PSU.