SLOU567B March   2025  – November 2025 THS3470

 

  1.   1
  2.   Description
  3.   Features
  4.   4
  5. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  6. 2Configuration Details
    1. 2.1 Heat Sink Usage
    2. 2.2 Power Connections
    3. 2.3 Input and Output Connections
    4. 2.4 Output Current Limits
    5. 2.5 Power Control Modes
    6. 2.6 Die Temperature and Output Current Readings
  7. 3Quick Start Instructions
    1. 3.1 Required Equipment for Basic Evaluation
    2. 3.2 Steps for Standard AC or DC Evaluation
    3. 3.3 Using Multiple Power Supplies
    4. 3.4 TI Evaluation Setup Images
  8. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Layouts
    3. 4.3 Bill of Materials (BOM)
  9. 5Additional Information
    1. 5.1 Trademarks
  10. 6Revision History

2.4 Output Current Limits

The THS3470 features both a sinking and sourcing output current limit function. The current limit values are set by the ISRC_LIMIT (pin 28) and ISINK_LIMIT (pin 7) pins with a resistor. The default EVM configuration features a resistor and potentiometer to adjust the limit and can be altered to change the total limit range as desired. Table 2-1 describes the relationship to properly set the current limits using the EVM resistors.

Table 2-1 THS3470 Current Limit Settings
Current LimitPin NumberCurrent Limit EquationEVM Resistors
Sourcing28ILIMIT = [(VSMID – VEE) / RISRC] × 2048RISRC = R17 + R18 + R22
Sinking7 ILIMIT = [(VCC – VSMID) / RISNK] × 2048RISNK = R27 + R28 + R31

Alternatively, to using the potentiometers, the limits can be shorted to resistors using jumpers J10 and J11 for quick switching between different values. If users are using this method, then R18 and R28 need to be removed.

The current limiting function is enabled by setting pin 3 low for the source limit or pin 4 low for the sink limit. The EVM includes switches S1 and S2 to control the current limit enable function. The switches can be set to GND to enable the limits, VDD to disable the limits, or the the overcurrent source and sink flag voltages to automatically enable the current limit when the flag is tripped.