SLUSFM1 December   2024 TPS4812-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 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 Switching Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Charge Pump and Gate Driver Output (VS, GATE, BST, SRC)
      2. 8.3.2 Capacitive Load Driving
        1. 8.3.2.1 Using Low-Power Bypass FET (G Drive) for Load Capacitor Charging
        2. 8.3.2.2 Using Main FET (GATE Drive) Gate Slew Rate Control
      3. 8.3.3 Overcurrent and Short-Circuit Protection
        1. 8.3.3.1 I2t-Based Overcurrent Protection
          1. 8.3.3.1.1 I2t-Based Overcurrent Protection With Auto-Retry
          2. 8.3.3.1.2 I2t-Based Overcurrent Protection With Latch-Off
        2. 8.3.3.2 Short-Circuit Protection
      4. 8.3.4 Analog Current Monitor Output (IMON)
      5. 8.3.5 NTC-Based Temperature Sensing (TMP) and Analog Monitor Output (ITMPO)
      6. 8.3.6 Fault Indication and Diagnosis (FLT)
      7. 8.3.7 Reverse Polarity Protection
      8. 8.3.8 Undervoltage Protection (UVLO)
    4. 8.4 Device Functional Modes
      1. 8.4.1 State Diagram
      2. 8.4.2 State Transition Timing Diagram
      3. 8.4.3 Power Down
      4. 8.4.4 Shutdown Mode
      5. 8.4.5 Low Power Mode (LPM)
      6. 8.4.6 Active Mode (AM)
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application 1: Driving Power at all times (PAAT) Loads With Automatic Load Wakeup
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Typical Application 2: Driving Power at all times (PAAT) Loads With Automatic Load Wakeup and Output Bulk Capacitor Charging
      1. 9.3.1 Design Requirements
      2. 9.3.2 External Component Selection
      3. 9.3.3 Application Curves
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

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発注情報

8.3.5 NTC-Based Temperature Sensing (TMP) and Analog Monitor Output (ITMPO)

TPS4812-Q1 features an integrated temperature monitoring amplifier (ON in active mode and load wakeup only). This temperature monitoring function is implemented with a differential amplifier with input pin as TMP and output pin as ITMPO.

The analog output voltage, VITMPO represents the temperature sensed by RNTCwhich can be directly read on pin ITMPO (Temperature monitoring output) by microcontroller.

VITMPO can be calculated based on following equation:

Equation 18. V I T M P O   =   V R E F _ T M P   +   V T M P _ O F F S E T   ×   R I T M P O R N T C   +   R T M P

where,

VREF_TMP is 500mV (typical)

VTMP_OFFSET is ±5mV

RTMP is 330Ω for 10k NTC at 25°C

RTMP is 1kΩ for 47k NTC at 25°C

TPS4812-Q1 has integrated comparator on ITMPO pin to detect external main FET overtemperature fault. When voltage on ITMPO exceeds above V(TMP_OT) (2V typ) threshold then main FET (GATE) turns off, device goes into latch-off and FLT asserts low. Latch is reset on falling edge of INP or LPM going low or EN/UVLO (below V(ENF)) or power cycle VS below V(VS_PORF).

External FET overtemperature threshold can be programmed based on following equation:

Equation 19. V (T M P _O T)   =   V R E F _ T M P   +   V T M P _ O F F S E T   ×   R I T M P O + R I N T R N T C   +   R T M P

Where,

RITMPO is resistor in ohm on ITMPO pin.

V(TMP_OT) is fixed external FET overtemperature threshold of 2V (typical).

RINT is internal resistor with 200Ω (typical) and 90/340Ω min/max value.

RNTC is the NTC thermistor resistance which varies with the temperature and RTMP is a normal resistor used to linearize the thermistor behavior with respect to temperature, shown in Figure 8-12:

TPS4812-Q1 NTC-Based Temperature Sensing and Monitoring Output Figure 8-12 NTC-Based Temperature Sensing and Monitoring Output