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I have started to using low power modes of PSoC 3 and i'm wondering how to minimize current consumption in hibernate mode.
I am using CY8C3866LTI-068ES3 device, i have made blank project - without any components, i have changed some parameters such as:
- disabled pll,
- master clock changed to IMO (3MHz),
- completly disable debugging port.
On my PCB i have 3.3V connected to: Vdda, Vcca, Vddio0, Vddio1, Vddio2, Vddio3, Vddd, Vccd
The ground is connected to: Vbat, Vb, Vssb, Vssd, Ex_Pad
All other pins are unconnected.
The only two lines in my code are:
CyPmSaveClocks(); //Save Clock configuration before entering Hibernate
CyPmHibernate(); // put the device into hibernate mode
When i measure current taken by PSoC 3 (after starting this program) it's about 100 uA - when in datasheet it says that it supouse to be about 200nA.
I'm wondering where such big difference comes from?
What can i change to minimize current consumption?
I was testing with forcing some pins to be outputs in high impedance, some to inputs and etc. - but any such move leads to bigger current.
I have also tried "Hibernate_WakeupWithPICU" (application note and example) - but the minimum current is the same (over 100uA).
I have attached example project which takes 100uA.
Thanks in advance for any help/hints.
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PSoC 3
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Hi,
Can you give us more information on the test setup? Are you using the Cypress DVk. Or is it a custom board. How are you measuring the current? Is it the board current or PSoC current that you are measuring?
-Udayan
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Hi,
Can you give us more information on the test setup? Are you using the Cypress DVk. Or is it a custom board. How are you measuring the current? Is it the board current or PSoC current that you are measuring?
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Hi,
Can you give us more information on the test setup? Are you using the Cypress DVk. Or is it a custom board. How are you measuring the current? Is it the board current or PSoC current that you are measuring?
-Udayan
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Thanks for reply.
So this is my custom board and i'm measuring board current.
But as i wrote, on my board there are just few capacitors between GND and VCC and all other pins are uconnected - they are floating. When i remove Cypress chip, the current is 0 - as it supouse to be.
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Hello,
I understand from your first commment that the VCCA terminal on PSoC is connected to VDDD/VDDA terminal as well. If this is the case what you are doing is wrong.
-
- PSoC3 has two internal 1.8V regulators that provide the digital (Vccd) and analog (Vcca) supplies for the internal core logic.
-
- The output pins of the regulators (Vccd and Vcca) have very specific capacitor requirements that are listed in the data sheet.
Hence you may have to connect VCCA and VCCD terminal to an appropriate capacitor. There is a possibility that the chip may not work because of excess voltage applied at VCCA.
-Udayan
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Yep, You are right!
- the one (Vcca) was was my mistake during writing that post. On PCB Vcaa is connected to 1uF capacitor - (not to 3.3V - as i wrote before)
- but Vccd is connected to 3.3V - so this can be the reason of these extra 100uAmps. (device is still working properly)
Thank You for finding it, i will change my design and PCB and try again soon.
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Hello Vac,
After making the changes, let us know if it works.
Thanks,
Udayan