SLVS500D DECEMBER   2003  – June 2019 TPS54110

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
  4. 4 Revision History
  5. 5 Device Information
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Recommended Operating Conditions
    3. 7.3 Thermal Information
    4. 7.4 Electrical Characteristics
    5. 7.5 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 VBIAS Regulator (VBIAS)
      2. 8.3.2 Voltage Reference
      3. 8.3.3 Oscillator and PWM Ramp
      4. 8.3.4 Error Amplifier
      5. 8.3.5 PWM Control
      6. 8.3.6 Dead-Time Control and MOSFET Drivers
      7. 8.3.7 Overcurrent Protection
      8. 8.3.8 Thermal Shutdown
      9. 8.3.9 Power Good (PWRDG)
    4. 8.4 Undervoltage Lockout (UVLO)
    5. 8.5 Slow-Start/Enable (SS/ENA)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical TPS54110 Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Switching Frequency
          2. 9.2.1.2.2 Input Capacitors
          3. 9.2.1.2.3 Output Filter Components
            1. 9.2.1.2.3.1 Inductor Selection
            2. 9.2.1.2.3.2 Capacitor Selection
          4. 9.2.1.2.4 Compensation Components
          5. 9.2.1.2.5 Bias and Bootstrap Capacitors
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Very-Small Form-Factor Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Two-Output Sequenced-Startup Application
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curve
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Layout Considerations For Thermal Performance
    4. 10.4 Grounding and Powerpad Layout
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PWP|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.5 PWM Control

Signals from the error-amplifier output, oscillator, and current-limit circuit are processed by the PWM control logic. Referring to the internal block diagram, the control logic includes the PWM comparator, OR gate, PWM latch, and portions of the adaptive dead-time and control-logic block. During steady-state operation below the current-limit threshold, the PWM-comparator output and oscillator pulse train alternately reset and set the PWM latch. Once the PWM latch is set, the low-side FET remains on for a minimum duration set by the oscillator pulse duration. During this period, the PWM ramp discharges rapidly to its valley voltage. When the ramp begins to charge back up, the low-side FET turns off and high-side FET turns on. As the PWM ramp voltage exceeds the error-amplifier output voltage, the PWM comparator resets the latch, thus turning off the high-side FET and turning on the low-side FET. The low-side FET remains on until the next oscillator pulse discharges the PWM ramp.

During transient conditions, the error amplifier output could be below the PWM ramp valley voltage or above the PWM peak voltage. If the error-amplifier output is high, the PWM latch is never reset and the high-side FET remains on until the oscillator pulse signals the control logic to turn the high-side FET off and the low-side FET on. The device operates at its maximum duty cycle until the output voltage rises to the regulation set-point, setting VSENSE to approximately the same voltage as Vref. If the error-amplifier output is low, the PWM latch is continually reset and the high-side FET does not turn on. The low-side FET remains on until the VSENSE voltage decreases to a range that allows the PWM comparator to change states. The TPS54110 is capable of sinking current continuously until the output reaches the regulation set-point.

If the current-limit comparator remains tripped longer than 100 ns, the PWM latch resets before the PWM ramp exceeds the error-amplifier output. The high-side FET turns off and low-side FET turns on to decrease the energy in the output inductor, and consequently the output current. This process is repeated each cycle that the current-limit comparator is tripped.