ZHCSL07C September   2019  – August 2021 TPS8802

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  System Power-up
      2. 8.3.2  LDO Regulators
        1. 8.3.2.1 Power LDO Regulator
        2. 8.3.2.2 Internal LDO Regulator
        3. 8.3.2.3 Microcontroller LDO Regulator
      3. 8.3.3  Photo Chamber AFE
        1. 8.3.3.1 Photo Input Amplifier
        2. 8.3.3.2 Photo Gain Amplifier
      4. 8.3.4  LED Driver
        1. 8.3.4.1 LED Current Sink
        2. 8.3.4.2 LED Voltage Supply
      5. 8.3.5  Carbon Monoxide Sensor AFE
        1. 8.3.5.1 CO Transimpedance Amplifier
        2. 8.3.5.2 CO Connectivity Test
      6. 8.3.6  Boost Converter
        1. 8.3.6.1 Boost Hysteretic Control
        2. 8.3.6.2 Boost Soft Start
      7. 8.3.7  Interconnect Driver
      8. 8.3.8  Piezoelectric Horn Driver
        1. 8.3.8.1 Three-Terminal Piezo
        2. 8.3.8.2 Two-Terminal Piezo
      9. 8.3.9  Battery Test
      10. 8.3.10 AMUX
      11. 8.3.11 Analog Bias Block and 8 MHz Oscillator
      12. 8.3.12 Interrupt Signal Alerts
    4. 8.4 Device Functional Modes
      1. 8.4.1 Sleep Mode
      2. 8.4.2 Fault States
        1. 8.4.2.1 MCU LDO Fault
        2. 8.4.2.2 Over-Temperature Fault
    5. 8.5 Programming
    6. 8.6 Register Maps
      1. 8.6.1  REVID Register (Offset = 0h) [reset = 0h]
      2. 8.6.2  STATUS1 Register (Offset = 1h) [reset = 0h]
      3. 8.6.3  STATUS2 Register (Offset = 2h) [reset = 0h]
      4. 8.6.4  MASK Register (Offset = 3h) [reset = 0h]
      5. 8.6.5  CONFIG1 Register (Offset = 4h) [reset = 20h]
      6. 8.6.6  CONFIG2 Register (Offset = 5h) [reset = 2h]
      7. 8.6.7  ENABLE1 Register (Offset = 6h) [reset = 10h]
      8. 8.6.8  ENABLE2 Register (Offset = 7h) [reset = 0h]
      9. 8.6.9  CONTROL Register (Offset = 8h) [reset = 0h]
      10. 8.6.10 SLPTMR1 Register (Offset = 9h) [reset = 0h]
      11. 8.6.11 SLPTMR2 Register (Offset = Ah) [reset = 0h]
      12. 8.6.12 GPIO_AMUX Register (Offset = Bh) [reset = 0h]
      13. 8.6.13 CO_BATTEST Register (Offset = Ch) [reset = 0h]
      14. 8.6.14 CO Register (Offset = Dh) [reset = 0h]
      15. 8.6.15 VBOOST Register (Offset = Eh) [reset = F2h]
      16. 8.6.16 LEDLDO Register (Offset = Fh) [reset = 0h]
      17. 8.6.17 PH_CTRL Register (Offset = 10h) [reset = 0h]
      18. 8.6.18 LED_DAC_A Register (Offset = 11h) [reset = 0h]
      19. 8.6.19 LED_DAC_B Register (Offset = 12h) [reset = 0h]
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Photo Amplifier Component Selection
        2. 9.2.2.2 LED Driver Component Selection
        3. 9.2.2.3 LED Voltage Supply Selection
        4. 9.2.2.4 Boost Converter Component Selection
        5. 9.2.2.5 Regulator Component Selection
      3. 9.2.3 Application Curves
      4. 9.2.4 3V Battery Smoke and CO Alarm
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Photo Amplifier Layout
      2. 11.1.2 CO Amplifier Layout
      3. 11.1.3 Boost Converter Layout
      4. 11.1.4 Ground Plane Layout
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 接收文档更新通知
    2. 12.2 支持资源
    3. 12.3 Trademarks
    4. 12.4 静电放电警告
    5. 12.5 术语表
  13. 13Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2.2.2 LED Driver Component Selection

The LED current depends on the TEMPCO bits, PDAC register and CSA and CSB resistors. Changing any of these values affects the LED current and temperature compensation. The following method selects the TEMPCO, PDAC, and CSA resistor value based on the required LED current and temperature compensation. The 100-mA LED current and 1 mA/°C temperature compensation is used as an example for LED A. Repeat the process for LED B.

  1. Determine the room temperature current and temperature compensation required by the application.
    • 100mA and 1mA/°C is required by the design.
  2. Calculate the compensation in percentage per degree by dividing the compensation coefficient by the current and multiplying by 100.
    • 1 mA/°C divided by 100 mA is 1%/°C.
  3. Use Table 9-1 or Table 9-2 to select a TEMPCO setting which contains the required compensation. If the required compensation is in two ranges, use the range with a higher TEMPCO setting. If the required temperature coefficient is not in any of the ranges, choose the TEMPCO and PDAC setting closest to the required temperature coefficient, then go to step 5.
    • 1%/°C is between the mimumum and maximum for TEMPCO = 11.
  4. Calculate the target CSA voltage. Divide the driver temperature coefficient [mV/°C] by the desired temperature coefficient [%/°C] and multiply by 100.
    • 1.040 mV/°C divided by 1 %/°C is 104 mV.
  5. Calculate the CSA resistor by dividing the target CSA voltage by the required current and subtracting 0.1 Ω for internal resistance.
    • 104 mV divided by 100 mA is 1.04 Ω. Subtract 0.1 Ω to get 0.94 Ω.
  6. Select the closest available resistor and calculate the final CSA voltage by multiplying the required current by the total resistance (external and internal).
    • Use a 0.92 Ω resistor. Multiply 100 mA and 1.02 Ω to get 102mV CSA voltage.
  7. Calculate the PDAC value by subtracting the final CSA voltage by the specified CSA voltage at PDAC = 0x00 and dividing the result by 1.176 mV (the DAC LSB, equal to 300 mV divided by 255).
    • 102 mV minus 79 mV is 23 mV, divided by 1.176 mV is 20. Write 0x14 to the PDAC register.
  8. Calibrate the PDAC value. If using the LED A driver, read the CSA_BIN register bits and add 0x11 if CSA_BIN=00b, add 0x06 if CSA_BIN=01b, subtract 0x06 if CSA_BIN=10b, or subtract 0x11 if CSA_BIN=11b. The CSA_BIN value varies from unit to unit and must be read on each unit calibrated using this method. Alternatively, measure the CSA or CSB voltage using the MCU ADC and adjust PDAC accordingly.
    • The microcontroller reads that a unit has CSA_BIN=01b. 0x20 is written to PDAC_A.
Table 9-1 Temperature Coefficients for Each TEMPCOA and DAC_A Setting
Register SettingCSA Voltage [mV],
T = 27°C		Temperature Coefficient [mV/°C]Temperature Coefficient [%/°C]Coefficient Information
TEMPCOA[1:0] = 11, PDAC_A = 0x00791.0401.316%Max for TEMPCO = 11b
TEMPCOA[1:0] = 11, PDAC_A = 0xFF3761.0400.277%Min for TEMPCO = 11b
TEMPCOA[1:0] = 10, PDAC_A = 0x001880.6930.369%Max for TEMPCO = 10b
TEMPCOA[1:0] = 10, PDAC_A = 0xFF4840.6930.143%Min for TEMPCO = 10b
TEMPCOA[1:0] = 01, PDAC_A = 0x002770.4160.150%Max for TEMPCO = 01b
TEMPCOA[1:0] = 01, PDAC_A = 0xFF5720.4160.073%Min for TEMPCO = 01b
TEMPCOA[1:0] = 00, PDAC_A = 0x002990.3470.116%Max for TEMPCO = 00b
TEMPCOA[1:0] = 00, PDAC_A = 0xFF5930.3470.059%Min for TEMPCO = 00b
Table 9-2 Temperature Coefficients for Each TEMPCOB and DAC_B Setting
Register SettingCSB Voltage [mV], T = 27°CTemperature Coefficient [mV/°C]Temperature Coefficient [%/°C]Coefficient Information
TEMPCOB[1:0] = 11, PDAC_B = 0x00811.0401.284%Max for TEMPCO = 11b
TEMPCOB[1:0] = 11, PDAC_B = 0xFF3791.0400.272%Min for TEMPCO = 11b
TEMPCOB[1:0] = 10, PDAC_B = 0x001890.6930.369%Max for TEMPCO = 10b
TEMPCOB[1:0] = 10, PDAC_B = 0xFF4860.6930.143%Min for TEMPCO = 10b
TEMPCOB[1:0] = 01, PDAC_B = 0x002770.4160.150%Max for TEMPCO = 01b
TEMPCOB[1:0] = 01, PDAC_B = 0xFF5720.4160.073%Min for TEMPCO = 01b
TEMPCOB[1:0] = 00, PDAC_B = 0x002990.3470.116%Max for TEMPCO = 00b
TEMPCOB[1:0] = 00, PDAC_B = 0xFF5940.3470.059%Min for TEMPCO = 00b

Use the same procedure for the blue LED, requiring 50 mA and 0.1 mA/°C, to calculate TEMPCOB = 10, RCSB = 6.8 Ω, VCSB = 345 mV, PDAC_B = 0x85 (before calibration).

The two drivers are identical, except for the CSA_BIN code to improve the accuracy of the LED_A driver for IR LEDs. Connect the IR LED to the LED A driver and the blue LED to the LED B driver in multi-wave systems.