SLUSEE5E January   2022  – April 2026 TPS4811-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Recommended Operating Conditions
    3. 6.3 ESD Ratings
    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, PU, PD, BST, SRC)
      2. 8.3.2 Capacitive Load Driving
        1. 8.3.2.1 FET Gate Slew Rate Control
        2. 8.3.2.2 Using Precharge FET - (with TPS48111Q1 Only)
      3. 8.3.3 Overcurrent and Short-Circuit Protection
        1. 8.3.3.1 Overcurrent Protection With Auto-Retry
        2. 8.3.3.2 Overcurrent Protection With Latch-Off
        3. 8.3.3.3 Short-Circuit Protection
      4. 8.3.4 Analog Current Monitor Output (IMON)
      5. 8.3.5 Overvoltage (OV) and Undervoltage Protection (UVLO)
      6. 8.3.6 Remote Temperature sensing and Protection (DIODE)
      7. 8.3.7 Output Reverse Polarity Protection
      8. 8.3.8 TPS4811x-Q1 as a Simple Gate Driver
    4. 8.4 Device Functional Mode (Shutdown Mode)
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application: Driving HVAC PTC Heater Load on KL40 Line in Power Distribution Unit
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Selection of Current Sense Resistor, RSNS
        2. 9.2.2.2 Selection of Scaling Resistor, RSET
        3. 9.2.2.3 Programming the Overcurrent Protection Threshold - RIWRN Selection
        4. 9.2.2.4 Programming the Short-Circuit Protection Threshold - RISCP Selection
        5. 9.2.2.5 Programming the Fault Timer Period - CTMR Selection
        6. 9.2.2.6 Selection of MOSFET, Q1
        7. 9.2.2.7 Selection of Bootstrap Capacitor, CBST
        8. 9.2.2.8 Setting the Undervoltage Lockout and Overvoltage Set Point
        9. 9.2.2.9 Choosing the Current Monitoring Resistor, RIMON
      3. 9.2.3 Application Curves
    3. 9.3 Typical Application: Driving B2B FETs With Pre-Charging the Output Capacitance
      1. 9.3.1 Design Requirements
      2. 9.3.2 External Component Selection
        1. 9.3.2.1 Selection of Pre-Charge Resistor
      3. 9.3.3 Application Curves
    4. 9.4 Typical Application: Designing for EMI
      1. 9.4.1 Common EMI Components
      2. 9.4.2 Programming the Overcurrent Protection Threshold with Added DC Resistance - RIWRN
      3. 9.4.3 Choosing the Current Monitoring Resistor with Added DC Resistance - RIMON
      4. 9.4.4 Programming the Short Circuit Protection Threshold with Added DC Resistance - RISCP
    5. 9.5 Power Supply and EMI Recommendations
    6. 9.6 Layout
      1. 9.6.1 Layout Guidelines
      2. 9.6.2 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

8.3.4 Analog Current Monitor Output (IMON)

TPS4811x-Q1 features an accurate analog load current monitor output (IMON) with adjustable gain. The current source at IMON terminal is configured to be proportional to the current flowing through the RSNS current sense resistor. This current can be converted to a voltage using a resistor RIMON from IMON terminal to GND terminal. This voltage, computed using Equation 12, can be used as a means of monitoring current flow through the system.

Use Equation 12 to calculate the V(IMON).

Equation 12. V ( I M O N ) = ( V S N S + V ( O S _ S E T ) ) × G a i n

Where:

  • VSNS = I_LOAD × RSNS
  • V(OS_SET) is the input referred offset (± 200µV) of the current sense amplifier (VSNS to V(IMON) scaling)

Use the following equation to calculate gain.

Equation 13. G a i n = 0.9 × R I M O N R S E T

Where:

  • 0.9 is the current mirror factor between the current sense amplifier and the IMON pass FET
The maximum voltage range for monitoring the current (V(IMONmax)) is limited to minimum([V(VS) – 0.5V], 5.5V) to establish linear output. This puts limitation on maximum value of RIMON resistor. The IMON pin has an internal clamp of 6.5V (typical).

Accuracy of the current mirror factor is < ± 1%. Use Equation 14 to calculate the overall accuracy of V(IMON).

Equation 14. % V ( IMON ) = V ( OS _ SET ) V SNS × 100

Figure 8-12 shows external connections and simplified block diagram of current sensing and overcurrent protection implementation.

TPS4811-Q1 Current Sensing and Overcurrent Protection Figure 8-12 Current Sensing and Overcurrent Protection