TIDUEZ4 May   2021

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  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 Support Resources
    4. 4.4 References
    5. 4.5 Trademarks
  10. 5About the Author

2.3.2 Power Requirements

Video surveillance products such as a video doorbell or Wi-Fi camera consist of a processor interfacing with high-speed image sensor and video encoder. The processor also interfaces with SD RAM, audio codec supporting two-way audio communication, and a lens driver with IR cut filter sub circuitry. From the power perspective many different supply rails are required to be generated to drive core voltage, I/O rail, and analog rail for the previously-mentioned peripherals.

The wireless MCU and the peripherals (except IR LED Driver) are designed to operate at standard 3.3 V logic levels. The IR LED driver is powered directly from the battery with a load switch in series.

Imaging sensors generally require two voltage sources for the analog and digital circuits in the chip. The analog circuits are typically powered from 2.8 V to 3.3 V and the digital circuits are powered from 1.2 V to 1.8 V. Similarly, video encoders require multiple power-supply rails: analog circuits powered from 3 V, the core and other digital circuits (I/O, PLL) powered from multiple power rails ranging between 1.0 V to 1.8 V. The power supply for the video encoder and image sensor must be designed to minimize ripple and transients in the output voltage to avoid image distortion.

The overall power supply requirements as well as power-tree for this reference design is illustrated in the Table 2-2.

Table 2-2 Power Requirements and Power-Tree Matrix
POWER RAIL MAXIMUM CURRENT CONSUMPTION INPUT COMMENTS IC
3.3 V Main Up to 1 A Battery or USB

MCU and peripherals

Always-on when battery input or USB input present

 TPS63802 buck-boost
3.3 V 100 mA 3.3 V Main

OA7000 analog supply

Triggered by MCU (HOST_ON)

 TPS22919 load switch
1.1 V 500 mA Battery or USB

OA7000 core supply

Triggered by MCU (HOST_ON)

 TPS62825 buck
1.35 V 200 mA Battery or USB

OA7000 DDR I/O supply

Triggered by MCU (HOST_ON)

 TPS62821 buck
1.8 V 200 mA Battery or USB

OA7000 I/O (PLL, NAND, JTAG) supply

SP2329 I/O supply

Triggered by MCU (HOST_ON)

 TPS62821 buck
2.5 V <100 mA Battery or USB

OA7000 eFuse

Triggered by OA7000 (EFUSE_SW)

 TPS7A0325 LDO
2.8 V 100 mA 3.3 V

SP2329 analog supply

Triggered by MCU (HOST_ON)

 TPS7A2028 LDO and TPS62840 buck