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Too much power consumption

Inbum Lee
Prodigy 110 points
Other Parts Discussed in Thread: MSP430F5437

We made small test board including msp430F5437.

The board works fine but too much power is consumed.

Below is the schematic, and removing any peripherals, It takes more than 400 uA in LPM3.

The right side of MSP is all opened and left side is mounted.

The test code is LPM3 example code supplied by TI. (see the code below)

Could you tell me what is the problem of this circuit?

 

 

#include  "msp430x54x.h"

 

void main(void)

{

  WDTCTL = WDTPW + WDTHOLD;                 // Hold WDT

  UCSCTL4 = SELM_1 + SELS_1 + SELA_1;       // MCLK = SMCLK = ACLK = VLO

 

  P1OUT = 0x00;

  P2OUT = 0x00;

  P3OUT = 0x00;

  P4OUT = 0x00;

  P5OUT = 0x00;

  P6OUT = 0x00;

  P7OUT = 0x00;

  P8OUT = 0x00;

  P9OUT = 0x00;

  P10OUT = 0x00;

  P11OUT = 0x00;

  PJOUT = 0x00;

 

  P1DIR = 0xFF;

  P2DIR = 0xFF;

  P3DIR = 0xFF;

  P4DIR = 0xFF;

  P5DIR = 0xFF;

  P6DIR = 0xFF;

  P7DIR = 0xFF;

  P8DIR = 0xFF;

  P9DIR = 0xFF;

  P10DIR = 0xFF;

  P11DIR = 0xFF;

  PJDIR = 0xFF;

 

  __bis_SR_register(LPM3_bits);             // Enter LPM3

  __no_operation();

}

  • 0
    Expert 1240 points

    CoreMind,

    Could you also post a schematic of your measurement system showing where and how the current is being measured, and with what sort of equipment?  This will help to pinpoint all of the branches where the current might be flowing.

    Sparkchaser

  • 0 in reply to sparkchaser
    Prodigy 110 points

    Dear sparkchaser

    Thank you for your interest and reply.

     

    I measured current with two different method.

    At first I connected 100ohm resistance serially into the power cable, then measured voltage between each side of resistance with oscilloscope.

    Second, instead of resistance, Fluke 289 digital multimeter was used to measure current directly.

    The multimeter's accuracy is lower than 5%.

     

    The results from these two experiments shows similar results.

     

     

  • 0 in reply to Inbum Lee
    Prodigy 60 points

    Electrolytic caps installed backwards can increase current consumption.

  • 0 in reply to Bob555
    Prodigy 60 points

    Also, don't forget that at high temperatures correctly installed caps cab be quite leaky, especially in the realm of LPM3.

  • 0 in reply to Bob555
    Prodigy 110 points

    Thank you for your interest and replies.

     

    The answer was outside of schematic I showed you.

     

    +3VA was not implemented so that AVcc and was not activated.

    The chip worked well but consumed more currents.

     

    I am really sorry for my mistakes.

    Best regards,

    Inbum Lee.

     

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