WL183x - maximum Power consumption

AnBer

Other Parts Discussed in Thread: WL1835MOD

Team,

There are some power consumption information at different places in the "WL1835MOD datasheet - SWRS152L" and “WL18xx Module HW intergartion UG - SWRU437”.
I am trying to find out how all the figures relate to each other in the WLAN use case.

For VBAT we have:
a) "Maximum power dissipation: 2.8 W" in section 5.4 of SWRS152L:
http://www.ti.com/product/WL1835MOD/datasheet/specifications#SWRA1702340

b) For calibration in table 6-1 of SWRS152L we have 3.6V x 850mA (which would be appr. 3.1W) on VBAT:
http://www.ti.com/product/WL1835MOD/datasheet/detailed_description#SWRS1526797
I understand note 2 as if the 30% are already included in the 850mA figures.

c) SWRU437 table-6 page 12 gives maximum current values:
   3.6V at 1A which makes 3.6W.

Q1: I think that b) superseed all the other information. The VBAT power supply must meet this power specification. Correct?
Or should 30% margin be added to the 850mA and c) would be the specification to meet?

Q2: At what VBAT voltage does this current value correspond to?
Do we have some information on what max current is at different VBAT? or should we assume 850mA max in all cases?

Q3: To what scenario does a) correspond to (VBAT voltage/current and VIO voltage/current)?

- For VIO:
a) SWRU437 table-6 page 12 gives:
   1.8V at 200mA
b) I did not find any max current for VIO.

Q1: Assuming that a) gives the max current for VIO:
on what use case is this maximum reached?
I guess that the SDIO activity the highest contributor to the VIO power. So the VIO power consumption depends on how much data are sent/received. Correct?
Any additional info available on the VIO current pattern?

Q2: what would be the VIO current consumption corresponding to the calibration phase? Should we assume 200mA?

Thanks in advance,

over 9 years ago

0 Eyal Reizer over 9 years ago

TI__Mastermind 20285 points

Hi,
Your thread has been assigned to our H/W expert. Please expect a follow up response.
BR,
Eyal

0 Rizwan Murji over 9 years ago

TI__Genius 13580 points

Hi Anber,

You have some excellent questions and can sometimes be a bit confusing. I will do my best to answer the topic / questions.

For VBAT we recommend a maximum supply voltage of 4.3V. You can operate at 4.8V but you will have a limited lifetime (2.33 years assuming operation at a 30% duty cycle). The data in the table is done for our typical VBAT voltage of 3.7V. During calibration for a short period of time you will reach up to 850mA. Our recommendation is that you size the VBAT supply to handle 1A for margin. Although if you calculate this for Power dissipation (3.7V x 0.85A = 3.2W) or at 4.3V you get 3.7W, this is only for a moment in time for calibration. The 2.8W maximum limit is a thermal limit of the package. Thus the device has been characterized and the internal algorithm of the WL18xx will ensure that the maximum power limitation is limited to 2.8W. What will happen internally is the power will roll back to maintain the max power dissipation limit. So to answer your questions:

Q1) Design the VBAT supply to be able to source 1A of current for margin

Q2) We specify this in the table at 3.7V. You can assume that the currents will be the same for the maximum voltage levels.

Q3) the 2.8W is the thermal limitation of the part and will roll back output power to not exceed this limit.

For VIO:

Q1) This is really user dependent on what they are doing with the SDIO lines. The spec is assuming all lines have activity and thus can be up to 200mA. We do not have any profiles for this.

Q2) During calibration, the VIO current is not affected as the VDD line is what is supplying the internal PA during calibration. The peak current is referring to VDD. That means assume 200mA max for VIO even during calibration as the SDIO lines may be active.

I hope this helps.

Thanks,

Riz

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WL183x - maximum Power consumption