TIDUDO6B May   2019  – October 2020

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Introduction to Parameters Measured Using TIDA-01580
    2. 1.2 High-Level System Description
    3. 1.3 Typical Applications
    4. 1.4 System Specifications and Design Features
    5. 1.5 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 AFE4900
      2. 2.2.2 CC2640R2F
      3. 2.2.3 TPS61099
      4. 2.2.4 TPS63036
      5. 2.2.5 TPD1E10B06
    3. 2.3 System Design Theory and Design Considerations
      1. 2.3.1  AFE4900 and Power Supply
      2. 2.3.2  CC2640R2F Microcontroller
      3. 2.3.3  PPG Measurement
      4. 2.3.4  ECG Measurement
        1. 2.3.4.1 Two-Electrode Configuration
        2. 2.3.4.2 Three-Electrode Configuration
      5. 2.3.5  Selecting TX Supply (TX_SUP) Value for Driving LEDs
      6. 2.3.6  Generating TX Supply for Driving LEDs
        1. 2.3.6.1 Programming Output Voltage
        2. 2.3.6.2 Maximum Output Current
        3. 2.3.6.3 Input and Output Capacitor Selection
        4. 2.3.6.4 Switching Frequency
        5. 2.3.6.5 WEBENCH® Simulation for TPS61099 Boost Converter
      7. 2.3.7  Generating RX Supply for AFE4900
        1. 2.3.7.1 Setting Output Voltage
        2. 2.3.7.2 Capacitor Selection
        3. 2.3.7.3 Output Current Limit
        4. 2.3.7.4 Inductor Selection
        5. 2.3.7.5 TINA-TI™ Simulation for TPS63036
      8. 2.3.8  Generating I/O Supply
      9. 2.3.9  Battery Input and Reservoir Capacitors
      10. 2.3.10 Battery Life Calculations
        1. 2.3.10.1 AFE4900 Current Consumption
        2. 2.3.10.2 CC2640R2F Current Consumption
        3. 2.3.10.3 On-State Current Calculations
        4. 2.3.10.4 Off-State Current Calculations (Considering Battery Voltage = 3 V)
      11. 2.3.11 External Memory
      12. 2.3.12 LED Indications
      13. 2.3.13 Connections Between Sensor Board and ECG Board
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 Connecting Optical Sensor and ECG Boards to Main Board
        2. 3.1.1.2 Difference Between PPG Sensor Boards
      2. 3.1.2 Software
        1. 3.1.2.1 Software Loading for TIDA-01580 Board (Transmit Side of BLE)
        2. 3.1.2.2 LabVIEW™ File Execution for Checking Measurement Data (Receive Side of BLE)
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
        1. 3.2.2.1 Heart-Rate Measurement Using PPG (Green LED) and ECG
        2. 3.2.2.2 SpO2 Measurement Using Red and IR LEDs
        3. 3.2.2.3 PTT Measurement
        4. 3.2.2.4 Lead-Off Detect
          1. 3.2.2.4.1 AC Lead-Off Detect
          2. 3.2.2.4.2 DC Lead-Off Detect
        5. 3.2.2.5 Low-Battery Indication
        6. 3.2.2.6 Waveforms for DC/DC Converters
        7. 3.2.2.7 Battery Life Test
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1  Layout for Main Board
      2. 4.3.2  Connection From PDs to AFE
      3. 4.3.3  Connections From LEDs to AFE
      4. 4.3.4  Connections From ECG PADs to AFE
      5. 4.3.5  Connections Between BT and AFE
      6. 4.3.6  Connections Between BT Antenna and Chip
      7. 4.3.7  Boost Converter
      8. 4.3.8  Buck-Boost Converter
      9. 4.3.9  Layouts for PPG Sensor Boards
      10. 4.3.10 Layout for ECG Sensor Board
      11. 4.3.11 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7About the Authors
  13.   Revision History

2.3.1 AFE4900 and Power Supply

Figure 2-2 shows different connections for the AFE4900 device.

The AFE4900 device needs three power supplies: TX_SUP, RX_SUP, and IO_SUP. TX_SUP (4.2 V) is generated using the TPS61099 device. RX_SUP (2.1 V) is generated using the TPS63036 device. IO_SUP is the same as RX_SUP.

For PPG measurement, the LEDs are driven using the TX2, TX3, and TX4 pins (TX1 is not connected in the design). The reflected signals are detected using PDs connected to the INP-INM and INP2-INM2 pins (INP3-INM3 pins are not connected in the design).

For ECG measurement, the signals coming from electrodes are connected to the INP_ECG and INM_ECG pins. The right-leg drive signal is available on RLD_OUT pin.

The BG pin is connected to the internal bandgap voltage. The BG pin is decoupled using a 0.1-µF capacitor (C11) on the board.

GUID-89EEB7F6-AA58-4C12-B5A8-FADE55EA7B6A-low.gifFigure 2-2 AFE4900 Connections Schematic

For the AFE4900 device, RX_SUP is filtered using an LC filter consisting of the ferrite bead L1 and capacitors C6 and C7.

Table 2-1 lists the connections between the AFE4900 and CC2640R2F devices.

Table 2-1 Connections Between AFE4900 and CC2640R2F
AFE4900 PIN NUMBERFUNCTIONCC2640R2F PIN NUMBERFUNCTIONCOMMENTS
E1/RESET6DIO_1Reset for the AFE
A4I2C_SPI_SELN/AN/ASelection between SPI and I2C. For this design, SPI is selected, so this pin is connected to RX_SUP through a 0-Ω resistor (R2).
F3I2C_CLK16DIO_10SPI_CLK
F2I2C_DAT14DIO_8SPI_IN
E2SDOUT15DIO_9SPI_OUT
E3SEN5DIO_0AFE_SPI_EN
D3PROG_OUT121DIO_15
F4ADC_RDY28DIO_18ADC ready signal
F1CLK29DIO_19AFE clock
B4CONTROL1N/AN/AEnables or disables the internal LDO. For this design, the internal LDO is enabled, so this pin is connected to GND through a 0-Ω resistor (R4).