PSOC3 (CY8C3865) sleep current too high (~28µA) - What could be the cause?

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Anonymous
Not applicable

Hi,

I have a design based on a CY8C3865LTI-014.

I noticed that in reality the sleep current was much too high than anticipated (more than 25µA higher).

The steps I took to debug this were:

- remove all components but the PSOC and the surrounding caps from the PCB

- build a fresh project without components, and only this code:

```

int main(void)

{

    CyGlobalIntEnable; /* Enable global interrupts. */

   

    // set 32kHz crystal to operate in low power mode when in sleep

    CyXTAL_32KHZ_SetPowerMode(1);

   

    //start WDT

    CyWdtStart(CYWDT_1024_TICKS,CYWDT_LPMODE_DISABLED);

   

    /* Place your initialization/startup code here (e.g. MyInst_Start()) */

    CyPmSaveClocks();

    for(;;)

    {

        /* Place your application code here. */

        // clear wdt

        CyWdtClear();

       

        // sleep 1 s

       

        CyPmSleep(PM_SLEEP_TIME_ONE_PPS,PM_SLEEP_SRC_NONE);

        CyPmReadStatus(CY_PM_ONEPPS_INT);

       

    }

    CyPmRestoreClocks();

}

```

As one can see, after initialisation, the PSOC goes in sleep mode forever.

When measuring the current, I still measure ~28µA, which is much more than the specified 1µA in the datasheet.

What could be the cause of this high sleep current?

I attached the project for you reference.

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4 Replies
VenkataD_41
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello Christopher,

Please share us the project schematic in this thread.

We have tested our PSoC 3 kit at our side with your application code and found that the sleep current is less han 1 micro ampere. So we wold like to check you project schematic.

Thanks

Ganesh

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Anonymous
Not applicable

Dear Ganesh,

Thank you for your reaction!

In attachment you will find:

- the schematic and board layout

- a picture showing the board I used for current measurements, where I desoldered all components except the PSoC and the caps and xtal surrounding it.

Thank you in advance for all your suggestions and remarks!

Kind regards,

Christopher

Christopher Peirs

Operations Manager

R&D Manager

Panimpex NV

T +32 58 42 14 50

M +32 472 92 25 39

Offices

Veurnestraat 162

B-8660 De Panne, Belgium

Production & Repairs

Sint-Idesbaldusstraat 37

B-8630 Veurne, Belgium

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Hi,

Please check whether the PSoC itself is consuming 28uA or the current consumed from the entire circuitry is 28A. Please note that there will be leakage currents based on the components and board design. Please confirm this.

Regarding PSoC firmware side, enabling the external oscillators will draw more current. So please be aware of this.

Follow the kit schematics for CY8CKIT-001 and PSoC 3 module and design accordingly.

http://www.cypress.com/documentation/development-kitsboards/cy8ckit-001-psoc-development-kit

Thanks

Ganesh

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Anonymous
Not applicable

The EE101 Insight-Pro at www.EE101.com does a great job measuring current for these types of designs!

BLECurrent.jpg

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