12 Replies Latest reply on Dec 21, 2011 2:09 AM by userc_44249




      I'm going to use  a 2,8V littium battery in order to supply the PSoC3 core with 1,8V through its own internal Analog and Digital Regulators.


      In my application I want to achieve very low consumption. Therefore, I would like to use the Power management modes such sleep, hibernation etc.


      I have just read the datasheet and the PSoC3 has 1 Sleep Regulator and 1 Hibernate Regulator but, unfortunately, there is no description for them in it.


      Could any one tell me how do they work? For example, when PSoC3 is in sleep mode, does the Sleep Regulator into operation inmediately delivering the 1,8V? And the same for the Hibernation?


      Thanks in advance.

        • 1. Re: Regulators

          Its an interesting topic that you have brought up. Let me answer your question one by one. PSoC3/PSoC5 device typically has the following reggulators:

          • Analog regulator for core, VCCA
          • Digital regulator for core, VCCD
          • Hibernate regulator for RAM etc during hibernate
          • I2C Regulator for I2C block while in sleep
          • Sleep reggulator for Sleep domain

          Typically, in active mode operation, the VCCA and VCCD suppies come from thhe Analog and digital regulators. 


          In hibernate mode, all the regulators except hibernate regulator is turned off. This generates what is called keep alive signal and provides it to necessary on chip circuitry that is responsible for state retention.


          In Sleep mode the operation is little different. In sleep mode, every regulator is disabled. The sleep regulator is turned. This reggulator powers VCCA and VCCD. The interesting thing with sleep is, this regulator is not supplied power continuously. Thhis regulator is powered intermittently on a periodic basis. This is called ''buzzing". The buzzing interval is determined a register value. 

          • 2. Re: Regulators

             In addition to this, the buzz interval actually controls the actual power consumtion indirectly. If for some reason the capacitor on VCCA and VCCD discharges quickly, it might be necessary to increase buzz frequency.


            Also note that if I2C address match is used to wake up the device, the I2C regulator is turned on.

            • 3. Re: Regulators

              Thanks for your answer U2.


              I have understood in general what you've said. I supose that the problems will come later, when I try it...



              • 4. Re: Regulators

                Hello again,


                following the topic of the supply with the 2,8V Battery, i have encountered with another doubt:


                I've thought supply Vddd and Vdda pins through 2,8V Battery. Then, it's supposed that the internal Analog and Digital regulators supply their corresponding parts with 1.8V, right?


                But what about the Vddio? Is it possible supply all the I/O pins with the internal 1,8V of the regulators? Or do I have to supply all the I/O ports with the external 2,8V battery? In my case, I'm interested in supply all the I/O ports with 1.8V.


                Thanks. Regards.

                • 5. Re: Regulators

                   I'm no expert on this,but I think if you tie the VDDIOs to the VCCA and VCCD rails,you should get 1.8V for all of them.

                  • 6. Re: Regulators

                    The VDDIOs are supplies required for the GPIOs to operate. Generally VDDIOs have to supplied from a seperate regulator. If shorted with VCCA, VCCD you might get 1.8V on all the pins, but we have not tried it yet. Note that if you tie VCCA/VCCD to VDDIOs and put the device to sleep you might see weird behavior. Because in Sleep mode, the regultors for VCCA and VCCD are not on always. These regulators are turned On at predetermined rate to charge the capacitors on VCCA and VCCD. If VDDIOs are supplied using these cpacitors, they might discharge at a faster rate. 

                    • 7. Re: Regulators

                      Thank's everyone.


                      @U2: I understand what you say. But, as you have also said, it's possible to change the buzz periode  of the Sleep Regulator by register. Therefore, if you set up a short periode of buzzing in order to supply faster the capacitors of Vcca and Vccd, would be possible to solve the conflict?



                      • 8. Re: Regulators

                        Trotis, generally if you observe we recommend a specific value of capacitor on the VCCA and VCCD terminals of PSoC3 device. These values are based on what is required for the internal regulator to operate consistently. If you connect VCCA/VCCD to VDDIO, you might end up adding additional capacitance. I would not discourage you from doing this, but you could always give it a shot to see if it works without any issues.


                        You can even try Buzzing the device at a higher frequency after connecting VCCA/VCCD to VDDIO, but we have not done anything like that in the past.

                        • 9. Re: Regulators

                          Thank's U2. I'll try it.



                          • 10. Re: Regulators

                            Thank's U2. I'll try it.



                            • 11. Re: Regulators

                              Kepp us updated via this thread, since you are doing something novel.

                              • 12. Re: Regulators

                                Consider it done. But for the time being, I'm working in other issues.


                                Thank's for your support.