SLUSFL6 June   2024 TPSM82866C

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Options
  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 I2C Interface Timing Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Power Save Mode
      2. 7.3.2 Forced PWM Mode
      3. 7.3.3 Optimized Transient Performance from PWM to PSM Operation
      4. 7.3.4 Low Dropout Operation (100% Duty Cycle)
      5. 7.3.5 Enable and Soft-Start Ramp
      6. 7.3.6 Switch Current Limit and HICCUP Short-Circuit Protection
      7. 7.3.7 Undervoltage Lockout
      8. 7.3.8 Thermal Warning and Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable and Disable (EN)
      2. 7.4.2 Output Discharge
      3. 7.4.3 Start-Up Output Voltage and I2C Target Address Selection (VSET)
      4. 7.4.4 Select Output Voltage Registers (VID)
    5. 7.5 Programming
      1. 7.5.1 Serial Interface Description
      2. 7.5.2 Standard-Mode, Fast-Mode, and Fast-Mode Plus Protocol
      3. 7.5.3 HS-Mode Protocol
      4. 7.5.4 I2C Update Sequence
      5. 7.5.5 I2C Register Reset
  9. 8 Register Map
    1. 8.1 Target Address Byte
    2. 8.2 Register Address Byte
    3. 8.3 VOUT Register 1
    4. 8.4 VOUT Register 2
    5. 8.5 CONTROL Register
    6. 8.6 STATUS Register
  10. 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 Input and Output Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
        1. 9.4.2.1 Thermal Considerations
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
  • RCF|15
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.6 Switch Current Limit and HICCUP Short-Circuit Protection

The switch current limit prevents the device from high inductor current and from drawing excessive current from the battery or input voltage rail. Excessive current can occur with a heavy load or shorted output circuit condition. If the inductor current reaches the threshold ILIM, cycle by cycle, the high-side MOSFET is turned off and the low-side MOSFET is turned on until the inductor current ramps down to the low-side MOSFET current limit.

When the high-side MOSFET current limit is triggered 32 times, the device stops switching. The device then automatically re-starts with soft start after a typical delay time of 128μs has passed. The device repeats this mode until the high load condition disappears. This HICCUP short-circuit protection reduces the current consumed from the input supply during an overload condition. Figure 9-23 shows the hiccup short-circuit protection.

The HICCUP can be disabled by the CONTROL register bit Enable HICCUP. Disabling HICCUP changes the overcurrent protection to latching protection. The device stops switching after the high-side MOSFET current limit is triggered 32 times. Toggling the EN pin, removing and reapplying the input voltage, or writing to the CONTROL register bit Software Enable Device unlatches the device.

The low-side MOSFET also contains a negative current limit to prevent excessive current from flowing back through the inductor to the input. If the low-side sinking current limit is exceeded, the low-side MOSFET is turned off. In this scenario, both MOSFETs are off until the start of the next cycle. The negative current limit is only active in forced PWM mode.