3 Replies Latest reply on May 29, 2015 5:13 PM by JoMe_264151

    PSoC 4 - High current consumption in hibernation mode 049-KIT



      I have done a simple project for my daughter, it’s a Lullaby tune player but with a hack!     



      I attach the project zip file.     



      The problem is that in hibernation mode I have a consumption current of 265uA instead of 1 to 6uA and after checking all the specifications I can’t see from where the current consumption is coming from.     



      The values are at 2.7Volts.     



      So that you understand the code, the project is a PSoC 4 049-KIT (3.8mA while playing the tune) without the USB-serial interface (this part consumes 2.7mA).     



      It has a power switch, 2 AA 1.5V batteries, a schottky Diode (0.3 v) to protect against polarity inversion, it has a piezo disk, it has a voltage divider (1MOhm and 10KOhm pot) (consumption 2.7uA), it uses the Low Power Comparator to exit from hibernation (6uA), it uses the switch from the board to enter a configuration mode and before it enters hibernation, all pins are configured to high Z (impedance). In hibernation mode the documentation states that the current consumption is from 150nA to 1uA.     



      When the power is turned on, it plays a Brahms Lullaby for 5 minutes then it goes to hibernation, if it detects movement in the piezo (can be a not very hard nok to the table 1.5meters in distance) the low power comparator wakes the system from hibernation and plays for another 5 minutes, and goes to hibernation.     



      If you press the 049-KIT button and turn the power on it enters a configuration mode to set the sensitivity of the movement with the potentiometer, in this mode it plays a 0.5 seconds beep and goes into hibernation, then you have to turn it off and on again to go into the normal mode.     



      My question is did I make something wrong that isn’t optimizing the current consumption?     



      Currently the batteries last for 280 days on hibernation, but I would like at least to improve by a factor of 25 to the 10uA range. I would like to know how much I can push this design with PSoC.     





      Thank you,     



      Best regards,     



      João Nuno Carvalho     


        • 1. Re: PSoC 4 - High current consumption in hibernation mode 049-KIT

          Start power reduction by disabling debug interface.


          in .cydwr-file -> System -> Debug Select = "GPIO"





          • 2. Re: PSoC 4 - High current consumption in hibernation mode 049-KIT

            You where right! 


            It was the debugger interface that had a current consumption of 260.5uA, the problem is resolved.




            The batteries now have a life of 6.6 years!!!!!     





            I know that the AA alkaline batteries discharge before 6.6 years but there are lithium batteries that last 10 years!     





            265uAh (Current consumption in hibernation  with the debugger interface turned on)     







            3.8mAh consumption while playing music.     



            4.5uAh total consumption in hibernation for the all project.     



            2.7uAh Consumption of the voltage divider     



            1.8uAh Consumption of PSoC 4 including Low Power comparator.     





            Two AA batteries of 1800mAh last 400 000 hours in hibernation, this is 16 666 days or 45 years, the batteries naturally discharge before that , but in the context of lithium batteries they last 10 years, and it starts to make sense, a great feet for something that costs only 4 dollars in a board!     





            I will give a practical example, in a normal utilization the little box plays the music once before my daughter sleeps, then with the lights turned off she knock’s on the table so that the box plays another time it plays 5 minutes + 5 minutes and the rest of the time is in hibernation while it is detecting movement.     





            Plays 2 times a day                                            10 minutes     



            Playing time                                                         0,17 of hour     



            Consumption playing in one hour                      0,0038 Ah  (3.8mAh)     



            Hibernation time                                                    24 hours     



            Consumption in hibernation                                 0,0000045 Ah  (4.5uAh)     



            AA Batteries capacity                                           1,8 A  2.7Volts     



            Number of days                                   2425     



            Number of years                                 6,643835616 <-------- 6.6 years (The alkaline batteries don’t last this long without naturally discharging, but there are lithium batteries that last 10 years)     



            Total current consumption                    1,797733333 A     





            This started like a labor of love, in the middle it was a hack, and it ended like a small piece off engineering! :-)     





            And in PSoC it was made in an instant, nice !!!!     





            Thank you very much,     





            Best regards,     



            João Nuno Carvalho     


            • 3. Re: PSoC 4 - High current consumption in hibernation mode 049-KIT

              You are always welcome!


              And a hug to your baby!