SLVSI14A March   2026  – September 2026 TPS922152

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Adaptive Off-Time Mode
      2. 6.3.2 Setting LED Current
      3. 6.3.3 VCC UVLO & Clamping
      4. 6.3.4 Dimming Mode
        1. 6.3.4.1 PWM Dimming
        2. 6.3.4.2 Analog Dimming
        3. 6.3.4.3 External Shunt Dimming
      5. 6.3.5 Fault Protection
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 TPS922152 60V Input Bus, 5A Output, 16-piece WLED With Analog and PWM Dimming
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Inductor Selection
          2. 7.2.1.2.2 MOSFET Selection
          3. 7.2.1.2.3 Diode Selection
          4. 7.2.1.2.4 MOSFET Selection
          5. 7.2.1.2.5 Diode Selection
          6. 7.2.1.2.6 Input Capacitor Selection
          7. 7.2.1.2.7 Output Capacitor Selection
          8. 7.2.1.2.8 Sense Resistor Selection
          9. 7.2.1.2.9 Other External Components Selection
        3. 7.2.1.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.1 Adaptive Off-Time Mode

The TPS922152 adopts an adaptive off-time current-mode control with quasi-constant frequency to maintain accurate current regulation and fast transient response over a wide load range.

For accurate output current regulation, the voltage sensed across the sense resistor via the CSZCD pin and ground is amplified and averaged to generate a voltage proportional to the output current. This sensed voltage is then compared, through the error amplifier, to the filtered ADIM voltage, which serves as the reference. The error voltage generated by the error amplifier regulates the PWM duty cycle, thereby enabling the output current to track the ADIM voltage. During each switching cycle, when the switching FET is turned on, the current is sensed through the CSZCD pin. The error amplifier output, VCOMP, passes through an internal compensation network and is compared to the rising edge of the sensed current. When the sensed current reaches VCOMP at the PWM comparator input, the switching FET is turned off to set the peak current.

An off-time counter begins counting immediately after the switching FET is turned off. The counting off time corresponding to a switching frequency is determined by the external resistor connected to the FSET pin. Once the off-time counter reaches the target, the off-time counter is reset and remains inactive until the next switching cycle begins. This mechanism allows the device to maintain a nearly constant switching frequency in both steady-state CCM and DCM. By connecting an external resistor between FSET pin and ground, the switching frequency can be set in the range of 50kHz to 1MHz. The resistor value and the corresponding switching frequency can be calculated using Equation 1

Equation 1. FSW=1RFSET×CFSET

where

  • CFSET = 100pF

Under light-load conditions, the device scales the peak current in proportion to the load. To maintain accurate regulation, the off-time is dynamically extended via Pulse Frequency Modulation (PFM). To maintain stability and prevent audible noise, the switching frequency is clamped at a minimum of 20kHz.

TPS922152 AOT mode average-current control Figure 6-1 AOT mode average-current control