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STM32F051 possible missconfig? makes Battery pin takes 100mA

Question asked by gnoss.juergen on Mar 5, 2013
Latest reply on Mar 6, 2013 by waclawek.jan
Hi, I have a STM32F051C6 on a PCB that has a socket for a Battery, connected to VBat using a Schottky diode.
While development phase I don't fit the battery, just use a jumper wire and connect the Plus of the battery socket to same supply as the MCU.
All the PCB uses 3.3V Supply, so I have 3V on VBat.

My circuits are always connected to power source using an programmable Amp-meter with Amp limitation.

At one instant (I was programming some Timers and ISR's) the Circuit tries to suck about 120mA, and the Amp-Meter instantly disconnected the entire circuit (because of preprogrammed 60mA max)

I investigated the cause and found that the VBat Pin tries to get about 100mA.
When I disconnect that Jumper wire to the battery socket, the entire circuit takes about 21mA and the MCU works normal.

I have no idea what caused that change.
Somebody please can give me an idea where to look for that.