How can I get the lowest power consumption ?

[shinnlin]

Posted on September 17, 2004 at 13:21

How can I get the lowest power consumption ?

[shinnlin]

Posted on September 14, 2004 at 13:12

We just mount Xtal, STR710, SD card slot, reset circuit and switching power regulator circuit on the target board to test the power consumption. Both internal Main Voltage Regulator and Low Power Voltage Regulator are turned off since we use external 1.8V and 3.3V.

The target board is powered by 1.5V DC from power supply.

Then, we test the DC current on the power +/-.

The measured DC current is always around 160mA in normal operation with main clock 8MHz.

If I turn off the Xtal and ask STR710 goes into STANDBY mode by PCU_EnterLPM( PCU_STANDBY), I get the low DC current at 16 mA.

( main VR and low power VR are both turned off )

The value seems still far away from what stated in datasheet ?!

( STANDBY mode current = 30 uA )

How can I get the lowest power consumption ?

Thanks in advance !!

[shinnlin]

Posted on September 17, 2004 at 00:05

May I know how you measure the power consumption in Table 7. Power Consumption, page 24 of STR71xF Data Sheet Rev. 3 ?

I'd like to know if we meet the limitation of this chip or not !!!

[hichem2]

Posted on September 17, 2004 at 13:21

Hi Shinn,

It's evident that in order to minimize power consumption, you can program the STR71xF to switch to SLOW, WAIT FOR INTERRUPT, STOP or STANDBY mode depending on the current system activity in the application.

I tried to measure STANDBY mode current and I found a near value of the one indicated in the datasheet (30 uA).

This that I propose for you:

1-Be sure that you measure the power consumption for the chip and not for the board. You can use the standby pin (STDBY) to switch off all the other devices implemented in the board.

2-Be sure that your software allows correctly the passage of the chip to the standby mode.

Hopefully this helps you.

kind Regards,

Hich