TIDUDW4B January   2019  – December 2024 CC2640R2F , TMP117

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMP119
      2. 2.3.2 CC2340R5
    4. 2.4 System Design Theory
      1. 2.4.1 Shelf Life and Active Life
      2. 2.4.2 Wearer Comfort
      3. 2.4.3 System Accuracy
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Software
        1. 3.1.2.1 Reading From the Patch
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
        1. 3.2.1.1 Current Consumption and Life Span
      2. 3.2.2 Test Results
        1. 3.2.2.1 Current Consumption and Lifespan
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Considerations for the CC2340R5
      2. 4.3.2 Layout Considerations for the TMP119
        1. 4.3.2.1 WCSP (YBG) Package
      3. 4.3.3 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
    7. 4.7 Related Documentation
    8. 4.8 Trademarks
    9. 4.9 Revision History

3.2.2.1 Current Consumption and Lifespan

Figure 3-6, Figure 3-7, and Figure 3-8 show the current consumption of the patch under various settings. Table 3-1 summarizes the results. In the final design, the patch was configured to auto-advertise every 5 seconds, and read temperature every 5 seconds. The connection interval is determined by the mobile device connected, but the device was only allowed to connect for 1% of the active time. The remaining 99% of the active time, the device was placed in advertizing mode.

Equation 1 shows how to estimate the patch power consumption over a lifetime. Equation 2 shows the test example calculation with two years of shelf life and five days of active time, divided into 99% advertising mode and 1% connection mode. Using the average currents measured during testing and the mentioned testing parameters, was calculated that the device consumes 4.86mAh of battery charge. This is less than the battery capacity of 5.5mAh.

Equation 1. Q Battery = I Shelf × T Shelf + ( I Advertise × P Advertise + I Connected × P Connected ) × T Active

where

  • QBattery is the charge consumed from the battery (in mAh)
  • IShelf is the current consumption during device shutdown (in mA)
  • TShelf is the time the patch spends in device shutdown (in hours)
  • IAdvertise is the average current consumption when the patch is active and in advertising mode (in mA)
  • PAdvertise is the percentage of time the patch is active and in advertising mode (out of 1)
  • IConnected is the average current consumption when the patch is active and in connection mode (in mA)
  • PConnected is the percentage of time the patch is active and in connection mode (out of 1)
  • TActive is the time the patch spends in active mode after shutdown (in hours)
Equation 2. 4 . 86 mAh = 0 . 000165 × 17520 + ( 0 . 0143 × 0 . 99 + 0 . 227 × 0 . 01 ) × 120
Table 3-1 Average Current Consumption
CONDITION MEASURED CURRENT DRAW ASSOCIATED FIGURE
Initialization (Start-up) 3.3mA (Avg) for 75ms Figure 3-6
Advertising 9.6mA (Peak) Figure 3-7

Advertising

 14.3µA (Avg) Figure 3-7
Connected 7.6mA (Peak) Figure 3-8
Connected 227.7µA (Avg) Figure 3-8
TIDA-01624 Start-Up Current Consumption Figure 3-6 Start-Up Current Consumption
TIDA-01624 Average Current for 1s Auto-Advertisement Figure 3-7 Average Current for 1s Auto-Advertisement
TIDA-01624 Average Current Consumption When Connected to a Smart Device Figure 3-8 Average Current Consumption When Connected to a Smart Device