CC3120MOD: power consumption calculation for indoor asset tracking.

Manjunath G14

Expert 2075 points

Part Number: CC3120MOD

Hi TI team,

This is Manjunath, Hardware engineer from Crevavi Technologies pvt ltd, Mysore

We have got a new requirement which is WiFi-Based indoor asset tracking for medical equipment in the hospital,

As I gone through the TI.com website I found CC3120MOD module suits,

Below are our target requirements:

The tags should be very very small
Need battery life of 5 years (the battery can be recharged onboard using something – we need to discuss)
Should withstand chemical cleaning (bleach etc)
Should be low cost.
These tags will directly work with the Wifi routers in the Customer locations (hospitals)
The tags will be used on IT (Laptop, desktops etc) and non IT medical devices (such as IV pumps)

Here the main concern is the battery life, Need a small battery with long life.

So here We need to consider the power saving modes in the Wifi module carefully and we should come out with the what is the battery spec and its life time with respect to the broadcast/advertising interval.

Current frequency of data transmission to be considered is 5min.

Please help us calculating the battery spec.

Thanks

Manjunath

Hardware Engineer

Crevavi Technologies pvt ltd, Mysore

over 4 years ago

0 Manjunath G14 over 4 years ago

Expert 2075 points

HI Team,

Request you to help on this immediately

0 Vincent Rodriguez over 4 years ago in reply to Manjunath G14

TI__Mastermind 28285 points

Manjunath,

I would take a look at this document that describes pretty well our current consumption in this use case:

http://www.ti.com/lit/an/swra628/swra628.pdf

Let me know if you have any additional questions.

Best Regards,

Vince

0 Manjunath G14 over 4 years ago in reply to Vincent Rodriguez

Expert 2075 points

Hi Vince,

I had gone through this document, can you give kne example to with calculation.

Below r the spec I have considered,

Tx current :229mA

Tx on time: 1sec

Sleep/shutdown current:5uA

Interval of data transmission for every 10min.

Battery spec:3.6v/1.2aH

Please correct if jm wrong kn above spec and share the battery life for the above mentioned spec.

Please reply ASAP.

THANKS

0 Vincent Rodriguez over 4 years ago in reply to Manjunath G14

TI__Mastermind 28285 points

Manajuth,

You'll need more info to accurately describe the power consumption ( # of packets, packet size, on which channel, output power?).

in section 5.2.2.1.2. there is a good example of the use case you are describing; if I use this as your use case, then during active mode (Sending packets) your average current is 22 mA for 90 ms. Assuming your sleeping for 10 mins @ 5 uA, this places the total average current around .008 uA, which with a 1200mAH battery would be around 50 days battery lifetime.

This is a rough estimate, and I encourage to perform the calculation yourself to verify.

BR,

Vince

0 Manjunath G14 over 4 years ago in reply to Vincent Rodriguez

Expert 2075 points

Hi Vince,

How did you get 22mA/90msec in active mode,

During transmission current it takes is 229mA as per the datasheet.

and time duration as per 5.2.2.1.2 section is around 25msec.

then have considered the wake-up time b/w hibernate and data transmit mode? How did you get 22mA/90msec in active mode,??

and if we consider your spec also

Active mode : 22mA/90msec in active mode,

during sleep/hibernate mode : 10mins@5uA

How did you get 50days as battery life.

Below are my calculations on the above information

Shutdown mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	600	Sec
Wake up mode current consumption (Iwp)	22mA	0.022	A
Wake up mode ON time (Twt)	90mSec	0.09	Sec
Data transmission interval (T)	10min	600	Sec

Average peak current during Shutdown mode	0.003	A
Average peak current during Active mode	0.00198	A

Average current consumed over T period (Iavg)	0.0000083	A
Battery Capacity (W)	1.2	AH
Battery life(C)= W / Iavg	144578.313253012	hours
	6024.0963855422	days
	16.9216190605	Years


Shutdown mode ON time(Tsd) = Data transmission interval(T)-(Wake up mode ON time+Active mode ON time)
Iavg= [(IsdTsd) + (ItxTtx)+(Iwp*Twp)] / T

Please check this also

Regards

Manjunath

0 Vincent Rodriguez over 4 years ago in reply to Manjunath G14

TI__Mastermind 28285 points

Manjunath,

Thanks for verifying. Yes i had my math incorrect. You're estimation looks correct. I get the 22mA over 90 ms from the measured data that I described earlier. In the diagram it shows the total time and average current for one burst of three packets. That is what I assumed as you TX cycle.

BR,

Vince

0 Manjunath G14 over 4 years ago in reply to Vincent Rodriguez

Expert 2075 points

Hi VInce,

Please find below calculations for different scenarios and just cross check with the spec I consider once.

LPDS mode
LPDS mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	600	Sec
Wake up mode current consumption (Iwp)	27mA	0.027	A
Wake up mode ON time (Twt)	20mSec	0.02	Sec
Data transmission interval (T)	10min	600	Sec

Average peak current during Shutdown mode	0.003	A
Average current consumed b/w wake up and data transmit over (T-Twt) period (Iavg)	0.00054	A

Average current consumed over T period (Iavg)	0.0000059	A
Battery Capacity (W)	1.2	AH
Battery life(C)= W / Iavg	203389.830508475	hours
	8474.5762711864	days
	23.8049895258	Years

Hibernate Mode
Hibernate mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	600	Sec
Wake up mode current consumption (Iwp)	22mA	0.022	A
Wake up mode ON time (Twt)	100mSec	0.1	Sec
Data transmission interval (T)	10min	600	Sec

Average peak current during Shutdown mode	0.003	A
Average current consumed b/w wake up and data transmit over (T-Twt) period (Iavg)	0.0022	A

Average current consumed over T period (Iavg)	8.66666666666667E-006	A
Battery Capacity (W)	1.2	AH
Battery life(C)= W / Iavg	138461.538461538	hours
	5769.2307692308	days
	16.205704408	Years

Shutdown mode(External slow clock)
Shutdown mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	600	Sec
Wake up mode current consumption (Iwp)	20.5mA	0.0205	A
Wake up mode ON time (Twt)	116mSec	0.116	Sec
Data transmission interval (T)	10min	600	Sec

Average peak current during Shutdown mode	0.003	A
Average current consumed b/w wake up and data transmit over (T-Twt) period (Iavg)	0.002378	A

Average current consumed over T period (Iavg)	8.96333333333333E-006	A
Battery Capacity (W)	1.2	AH
Battery life(C)= W / Iavg	133878.765340275	hours
	5578.2818891781	days
	15.6693311494	Years

Thanks & regards,

Manjunath

Hardware design engineer

LPDS mode
LPDS mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	600	Sec
Wake up mode current consumption (Iwp)	27mA	0.027	A
Wake up mode ON time (Twt)	20mSec	0.02	Sec
Data transmission interval (T)	10min	600	Sec

Average peak current during Shutdown mode	0.003	A
Average current consumed b/w wake up and data transmit over (T-Twt) period (Iavg)	0.00054	A

Average current consumed over T period (Iavg)	0.0000059	A
Battery Capacity (W)	1.2	AH
Battery life(C)= W / Iavg	203389.830508475	hours
	8474.5762711864	days
	23.8049895258	Years

0 Vincent Rodriguez over 4 years ago in reply to Manjunath G14

TI__Mastermind 28285 points

Hi,

The LPDS current is not the same as hibernate. LPDS current is around 120 uA.

BR,

Vince

0 Manjunath G14 over 4 years ago in reply to Vincent Rodriguez

Expert 2075 points

Hi VInce,

Yes you are right?

Please confirm the below calculations finally.

LPDS mode

LPDS mode
LPDS mode current consumption (Isd)	120uA	0.00012	A
Shutdown mode ON time (Tsd)	10min	3600	Sec
Wake up mode current consumption (Iwp)	27mA	0.027	A
Wake up mode ON time (Twt)	20mSec	0.02	Sec
Data transmission interval (T)	10min	3600	Sec

Average peak current during Shutdown mode	0.432	A
Average current consumed b/w wake up and data transmit Over (T-Twt) period (Iavg)	0.00054	A

Average current consumed over T period (Iavg)	0.00012015	A
Battery Capacity (W)	1.2	AH	By considering the Self discharge 1%
Battery life(C)= W / Iavg	9987.5156054931	hours	9887.6404494382
	416.1464835622	days	411.9850187266
	1.1689507965	Years	1.1572612886

Hibernate Mode

Hibernate Mode
Hibernate mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	3600	Sec
Wake up mode current consumption (Iwp)	22mA	0.022	A
Wake up mode ON time (Twt)	90mSec	0.09	Sec
Data transmission interval (T)	10min	3600	Sec

Average peak current during Shutdown mode	0.018	A
Average current consumed b/w wake up and data transmit Over (T-Twt) period (Iavg)	0.00198	A

Average current consumed over T period (Iavg)	0.00000555	A
Battery Capacity (W)	1.2	AH	By considering the Self discharge 1%
Battery life(C)= W / Iavg	216216.216216216	hours	214054.054054054
	9009.009009009	days	8918.9189189189
	25.3062050815	Years	25.0531430307

Shutdown mode:

Shutdown mode(External slow clock)
Shutdown mode current consumption (Isd)	5uA	0.000005	A
Shutdown mode ON time (Tsd)	10min	3600	Sec
Wake up mode current consumption (Iwp)	20.5mA	0.0205	A
Wake up mode ON time (Twt)	116mSec	0.116	Sec
Data transmission interval (T)	10min	3600	Sec

Average peak current during Shutdown mode	0.018	A
Average current consumed b/w wake up and data transmit Over (T-Twt) period (Iavg)	0.002378	A

Average current consumed over T period (Iavg)	5.66055555555556E-006	A
Battery Capacity (W)	1.2	AH	By considering the Self discharge of 1%
Battery life(C)= W / Iavg	211993.326136029	hours	209873.392874669
	8833.0552556679	days	8744.7247031112
	24.8119529654	Years	24.5638334357

0 Vincent Rodriguez over 4 years ago in reply to Manjunath G14

TI__Mastermind 28285 points

Yes this looks correct.

BR,

VInce

0 Manjunath G14 over 4 years ago in reply to Vincent Rodriguez

Expert 2075 points

Thanks Vince

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CC3120MOD: power consumption calculation for indoor asset tracking.