Is it ok to switch VDD and PVDD of CLRC663PLUS on/off while TVDD is powered?

[pekka_leinonen]

Hi,

I would like to keep TVDD of CLRC663PLUS powered most of the time, but I would like to switch VDD and PVDD on/off separately from TVDD to save power. Do you see any problems in this?

Is there fore example a risk that current flows from TVDD power rail into those other power rails which are switched off?

I assume that PDOWN pin should be driven low when VDD and PVDD are not powered. So is following condition ok in a low power device:

- PDOWN = 0

- VDD = 0

- PVDD = 0

- TVDD = 3.3V - 4.2V

Br, Pekka

[Kan_Li]

Hi Pekka,

VDD, PVDD and TVDD are independent from each other. so I could not see any problem in this, but I could not find what the purpose is as well. Would you please clarify? For power saving? and please also note "A hard power-down is enabled with HIGH level on pin PDOWN."

Have a great day,
Kan

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[pekka_leinonen]

Hi Kan,

In my system there are two supplies for CLRC663plus. A 3.3v linear regulator for VDD and PVDD and an other 3.3V - 4.2V for TVDD. Both of these supplier are shared also with other modules than CLRC663plus. There are situations (unrelated to CLRC663plus) where some power saving can be achieved by disabling 3.3V regulator although the other supply 3.3V - 4.2V needs to be kept powered.

Br, Pekka

[Kan_Li]

Thanks for the clarification! 

Have a great day,
Kan

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[pekka_leinonen]

Thanks!