[Vybrid] Lowpower current too much

[torus1000]

Hi.
According to the Vybrid data sheet on p20, max number*1 of lowpower current exceed 300mA.
   http://cache.freescale.com/files/microcontrollers/doc/data_sheet/VYBRIDFSERIESEC.pdf

Is there any workaroud to reduce such large current in lowpower mode?

If these max numbers include external NPN Ballast current, may an article*2 help to resolve this issue?

   Note *1: The Max numbers represent the single worst case value taken from a matrix
            lot of parts across normal process variation at maximum temperature.

   Note *2: https://community.freescale.com/message/335416#335416
            1) use PMIC can supply 3.3 1.2 1.5V simultaneously.
            2) use NPN for 1.2V

[torus1000]

Thank you, Naoum. Your answer will be helpful for my customer.

Unfortunately I couldn't access following URL:
      https://community.freescale.com/message/316584#316584
then following message came up.
      Unauthorized
      Access to this place or content is restricted. If you think this is a mistake,
      please contact your administrator or the person who directed you here.

Could you copy contents to my SR space ?
      FSL SR# 1-1086058751 : Vybrid low power current

Sorry for bother you.

B.R. Tohru

[naoumgitnik]

Dear Tohru-san,

Unfortunately, according to our company policy, we can only share such engineering data arrays with customers having signed an NDA.

The proper way of getting such data is via a local FAE in Japan.

Sincerely yours, Naoum Gitnik.

[naoumgitnik · Accepted solution]

Dear tohrusenbongi,

The low-power mode referred by you is named this way due to that Vybrid consumes in it relatively less power than in the high-power modes listed above it in the datasheet table. All the numbers in it refer to 1.2V core power as well, since the power scheme used is single-rail (3.3V only).

If you decide to keep the existing, i.e. linear, power management scheme, the only “workaround” is the one you've already found – lower ballast NPN transistor’s collector voltage. In this case you generate 3.3V (for I/Os) and 1.5V (for DDR) using switch-mode voltage regulators, and use 1.5V for the ballast transistor’s collector (whose size can be reduced tremendously). Then the 1.5V-to-1.2V conversion efficiency will be 80%, very close to that of a regular switch-mode voltage regulator, but the solution much simpler and cheaper.

Please also check if you can lower consumption by turning off Vybrid's blocks not used by your specific use case (refer to our documentation for details).

More detailed Vybrid power consumption data, for various use cases, can be found on the below link (not sure, though, if you have access permission for that):

https://community.freescale.com/message/316584#316584.

Sincerely yours, Naoum Gitnik.