8 Replies Latest reply on Apr 10, 2014 7:42 AM by user_14586677

    PSoC 5LP Consumption in Hibernate

    user_366036678

       Hello (again),

         

       

         

      I'm trying to measure the consumption for the PSoC 5LP (to be precise, CY8C5868LTI-LP039) device.

         

       

         

      Currently I'm just measuring power consumption with nothing in the schematics, but I change the operating modes (I cover all the modes possible).

         

       

         

      All other modes seems fine (even Sleep mode comes close to what the datasheets say, ~2 µA), except for the Hibernate mode, which somehow consumes ~45µA (well, that's what came up on the DMM screen).

         

       

         

      My current setup is using a DMM set to DC ammeter connected in series with the PSoC VDD (Digital, Analog and IO pins are tied together). The wirings and connections all follow the guidelines given by the documentations.

         

       

         

      Could this be a problem with wakeup? Currently all IO pins are not connected to anything. I didn't restore the clocks either after CyPmHibernate() since I thought that the device would hibernate forever. Maybe that isn't the case.

         

       

         

      Any ideas?

        • 1. Re: PSoC 5LP Consumption in Hibernate
          user_14586677

          "(Digital, Analog and IO pins are tied together)"

             

           

             

          What do you mean by this ?

             

           

             

          Are you doing this in a DVK board ? If so which one.

             

           

             

          Regards, Dana.

          • 2. Re: PSoC 5LP Consumption in Hibernate
            user_366036678

             Hello,

               

             

               

            Nope, it's on a custom circuit board.

               

             

               

            Tied together means, in this case, that they all share the same voltage source. On the board, the pins VDDD, VDDA and VDDIOx are all connected to a single terminal.

            • 3. Re: PSoC 5LP Consumption in Hibernate
              user_14586677

              You've seen this and followed the recommendations ?

                 

               

                 

                  

                 

                        

                 

              http://www.cypress.com/?docID=44199     AN77900

                 

               

                 

               

                 

              Regards, Dana.

              • 4. Re: PSoC 5LP Consumption in Hibernate
                user_366036678

                 Yep, seen it already, although I haven't actually applied any of the recommendations since I'm just trying to measure the static consumption.

                   

                 

                   

                Actually, I'm just trying to assess the best method to measure power consumption. I therefore need to know a configuration whose consumption is known (e.g. ~2µA in Sleep).

                   

                 

                   

                The only problem is that when I get to Hibernate, the measurements are not following the trend.

                • 5. Re: PSoC 5LP Consumption in Hibernate
                  user_366036678

                   Hello,

                     

                   

                     

                  I haven't been working with the device lately (been working on something else),

                     

                   

                     

                  But today I have finally solved the problem.

                     

                   

                     

                  In the DWR file, I changed the Programming/Debugging mode to GPIO and for the sake of it, I enabled Device Protection. I don't think it's necessary, but what the heck.

                     

                   

                     

                  And voila, it worked neatly. I got a baseline consumption of about 140 nA (kinda worrying if you ask me, it should be a bit higher).

                     

                   

                     

                  I'm not sure why it didn't work before, but my guess is that since I had the Programming/Debugging option set to SWD/SWV beforehand, the PSoC might be trying to stream debug data thru the debug port and maybe that consumes current (not sure how, since the MiniProg is disconnected) or it woke the PSoC up (again, the pins are not connected to each other, so how is that even possible).

                     

                   

                     

                  Oh, I also changed the Temp Range to 0 - 85/125 C. Could it be possible that that parameter causes the consumption to drop as well?

                  • 6. Re: PSoC 5LP Consumption in Hibernate
                    user_1377889

                    As you can see the temp range defines the limits within the announced power consumption will be fulfilled. Since you are not working at 85°C (presumably) your device consumes less than the specified rating.

                       

                     

                       

                    Bob

                    • 7. Re: PSoC 5LP Consumption in Hibernate
                      user_116077597

                      I'm at the same issue today (low energy) and I read the AN Dana linked, and on page 12 there is a chapter "Is Your Debug Interface Running? " where this is described. This could help you to understand what happened (although you described it).

                      • 8. Re: PSoC 5LP Consumption in Hibernate
                        user_14586677

                        Power consumption in CMOS a tad complicated. As T rises Rdson rises,

                           

                        dues to Vth rising, so switched R load based Pdiss drops. But then leakage

                           

                        rises dramatically with T, increasing that componet of Pdiss.

                           

                         

                           

                        Switching based Pdiss laregly just a f( f,C, V ).

                           

                         

                           

                        If you look at datasheet you will see Idd largely flat over T -