JAJU817 May   2021

 

  1.   概要
  2.   リソース
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1System Description
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 SimpleLink MCU
        1. 2.2.1.1 CC3235MODS
        2. 2.2.1.2 CC1352R LaunchPad
          1. 2.2.1.2.1 CC1352R
      2. 2.2.2 Power
        1. 2.2.2.1 TPS63802
        2. 2.2.2.2 TPS63900
        3. 2.2.2.3 TPS62825
        4. 2.2.2.4 TPS7A03
        5. 2.2.2.5 TPS7A20
        6. 2.2.2.6 TPS62840
        7. 2.2.2.7 TPS22919
        8. 2.2.2.8 LM66100
      3. 2.2.3 Peripherals
        1. 2.2.3.1 OPT3004
        2. 2.2.3.2 DRV8837C
        3. 2.2.3.3 TPA2011
        4. 2.2.3.4 TLV61048
      4. 2.2.4 OmniVision Video Encoder OA7000
      5. 2.2.5 OmniVision Image Sensor SP2329
      6. 2.2.6 YTOT Lens Module
    3. 2.3 Design Considerations
      1. 2.3.1  Input Power: Battery and USB
      2. 2.3.2  Power Requirements
      3. 2.3.3  Camera Wake-up and Day or Night Sensing
        1. 2.3.3.1 PIR and MSP430 Based Motion Detection Design for Low Cost and High Performance
      4. 2.3.4  Battery Gauging
      5. 2.3.5  IR LED Illumination
      6. 2.3.6  IR Cut Filter
      7. 2.3.7  Audio
      8. 2.3.8  System Operation
      9. 2.3.9  Wi-Fi and Host Subsystem
      10. 2.3.10 Firmware Control
        1. 2.3.10.1 Application Flow
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware
    2. 3.2 Software
    3. 3.3 Setup
      1. 3.3.1 Configuration Steps for Video over Wi-Fi
      2. 3.3.2 (Optional) Flash OA7000 With Latest Firmware or Stream Video Over USB
      3. 3.3.3 Audio Streaming
      4. 3.3.4 LPSTK-CC1352R Configuration Steps for Camera Module
    4. 3.4 Test Results
      1. 3.4.1 Power Supply Rails and Current Consumption
      2. 3.4.2 Battery Life Calculations
      3. 3.4.3 Video Streaming
      4. 3.4.4 IR LED Drive
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 Bill of Materials
    2. 4.2 Software
    3. 4.3 サポート・リソース
    4. 4.4 References
    5. 4.5 Trademarks
  10. 5About the Author

3.4.2 Battery Life Calculations

The following parameters affect the battery-life and power consumption for the entire system:

  • Capacity rating of battery (mAH)
  • Average off-state current consumption (mA)
  • Off-state duration (s)
  • Average on-state current consumption (mA)
  • On-state duration (s)

Equation 1 describes the estimated battery life for this design:

Equation 1. GUID-20210407-CA0I-B25G-9QQ3-7DVTHGGCTR8L-low.gif

Where:

  • IONAVG is the average on-state current consumption in mA
  • TON is the on-state duration in seconds
  • IOFFAVG is the average off-state current consumption in mA
  • TOFF is the off-state duration in seconds
  • Derating factor accounts for self aging of the battery - typically 80%

Substituting available battery capacity = 2100 mAH, TON = 5 s, number of activations per day = 5, IONAVG measured = 200 mA, IOFFAVG measured = 2 mA, TOFF per day = (24 × 60 × 60) - TON = 86375 s from Equation 1, the estimate for one month of battery life is shown in Equation 2.

Equation 2. GUID-20210422-CA0I-QDLF-QVHT-Z3RZ7K6WGP7H-low.gif

Software can be further optimized to achieve the standby current consumption of < 0.3 mA (CC3235MODS standby current of 120 μA for MCU in LPDS mode and NWP in idle mode), CC1352R standby current of 3 μA, 5 μA shutdown current for other peripherals and up to 100 μA current due to passives). This results in battery life of higher than 6 months as shown in Equation 3. Battery life of 1.5 years is achieved with 6000 mAH battery capacity for similar conditions. Table 3-2 and Table 3-3 show battery lifetime versus the number of activations for different battery capacities.

Equation 3. GUID-20210422-CA0I-1WHB-XQNN-S9CGQCMPCLXB-low.gif
Table 3-2 Battery Lifetime vs Number of Activations for 6000 mAH Battery
BATTERY CAPACITY (mAH) ACTIVE DURATION (s) NUMBER OF ACTIVATIONS PER DAY BATTERY LIFE
6000 5 5 1.5 years (18 months)
6000 5 10 1.3 years (16 months)
6000 5 15 1.1 years (14 months)
6000 5 20 1 year (12 months)
6000 5 25 0.9 year (11 months)
6000 5 30 0.8 year (10 months)
6000 5 35 0.7 year (9 months)
Table 3-3 Battery Lifetime vs Number of Activations for 2100 mAH Battery
BATTERY CAPACITY (mAH) ACTIVE DURATION (s) NUMBER OF ACTIVATIONS PER DAY BATTERY LIFE
2100 5 5 6.4 months
2100 5 10 5.5 months
2100 5 15 5 months
2100 5 20 4.3 months
2100 5 25 4 months
2100 5 30 3.5 months
2100 5 35 3.2 months

To optimize the system for even longer battery life, optimize the following factors:

  • Longer TOFF for each device
  • Shorter TON for each device
  • Lower ION and IOFF for each device
  • Lessen the number-of-activations per day