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Reduce startup power of Kinetis

Question asked by CARLOS OTERO on Aug 6, 2015
Latest reply on Aug 13, 2015 by David Diaz Marin

Hello community,


I would really appreciate any insight with reducing the power while doing a cold start for the KL03.



Some background:

I am using a KL03, custom board. I want to minimize the power used during a cold start as Vdd rises to settle at 1.8V. In order to quantify this, I didn't populate any components other than a 10k resistor between Vdd and Vss and a 1uF between Vdd and Vss. Then I would start with Vdd=0V and raise Vdd on 0.2V increments.  I would look then at the power draw using an ammeter (I dont know the voltage drop of the ammeter). I also looked at the voltage on the reset pin


Here are my results:


Vdd   |  I_vdd    |   V_reset

0            0              0

0.2         0              0.17

0.4         6u            0.4

0.6         33u          0.6

0.8         180u        0.1

1.1        300u          0

1.2        440u          0

1.4        370u          0

1.6       320u           0

1.7       20u            1.7   <<--- application is supposed to use 30uA, so we are good here



Then, I removed the resistor between Reset and Vdd ( there is an internal 20k-50k pup resistor there anyway).


Vdd   |  I_vdd    |  

0            0             

0.2         0             

0.4         0u            

0.6         40u         

0.8         130u       

1.0         200u        

1.2        210u         

1.4        150u         

1.6       370u         

1.7       20u          



So, removing the resistor between Reset and vdd seems to help a bit at the risk of having noise on Reset. I would like to reduce the power consumption even more _WITHOUT_ external active components (resistors, caps, etc are ok).


Any suggestions on what to do would be greatly appreciated..


I don't think it's relevant, but upon powering up, the chip sets  LVDV on, sets it's  clock at 60kHz and then toggles an LED at ~2Hz while entering and leaving VLPS (using LPTM to wake up).  The results posted are WITHOUT the LED, but the functionality was verified with the LED