Power consumption of Controller (and circuit)

[adeel.sid]

In my circuit, there are two main components: 1- Pic628A and 2- Bluetooth module
BT power consumption is 7mW (tx) and controller datasheet says 800mW
Three transistors are also connect LED to controller.
the circuit will work on demand so i put switch to on when needed.
It is expected to used it for 3hr a day
What battery capacity will be required in mAhr?
Can anyone suggest nano/micro power controller? (4 I/Os and UART are enough)

Regards

 

[wp100]

Hi,

You need to check your calculations.

First , what voltage are you running the 628 and BT module at.

Are you intending to run direct from a battery or via a regulator, if so what type ?

Would be interesting to have a link to that BT model datasheet and also know if you are constantly transmitting or receiving for that 3 hours of use.

Look at page 1 of the 628s datasheet and you will see it uses micro amps , not 800mw A = W/V =.8/5 = 160ma

My concern would be the current draw from the LED, what is its function , duration and current ?

Because the 628 is, or can be made to run at low power compared to the led and BT module I would not think it worthwhile trying to use a Xteme low power chip.

 

[FvM]

You are reporting PIC16F628A absolute maximum ratings as power consumption. I presume, you didn't understand the meaning of this datasheet paragraph. Actual power consumption must be calculated according to the DC Characteristics section.

 

[adeel.sid]

Hi,

First , what voltage are you running the 628 and BT module at.

Are you intending to run direct from a battery or via a regulator, if so what type ?

BT through LM3940 (3.3 V out)
PIC directly from 5v Battery
Tx power of BT is 7dbm
{https://www.digikey.com/product-detail/en/WT32I-E-AI6/1446-1037-6-ND/4806567}

 

[wp100]

BT through LM3940 (3.3 V out)
PIC directly from 5v Battery
Tx power of BT is 7dbm
{https://www.digikey.com/product-detail/en/WT32I-E-AI6/1446-1037-6-ND/4806567}

Hi,

Think the only true way to establish the power used will be to test the complete working circuit with a multi-meter.

You can use datasheets but they are bench test figures only, often quiet different from final project figures.