SLVSGH1B April   2023  – February 2025 TPS923652 , TPS923653 , TPS923654 , TPS923655

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 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 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 Adaptive Off-Time Current Mode Control
        1. 7.3.1.1 Switching Frequency Settings
        2. 7.3.1.2 Spread Spectrum
      2. 7.3.2 Setting LED Current
      3. 7.3.3 Undervoltage Lockout
      4. 7.3.4 Internal Soft Start
      5. 7.3.5 Dimming Mode
        1. 7.3.5.1 PWM Dimming
        2. 7.3.5.2 Analog Dimming
        3. 7.3.5.3 Hybrid Dimming
        4. 7.3.5.4 Flexible Dimming
      6. 7.3.6 CC/CV Charging Mode
      7. 7.3.7 Fault Protection
      8. 7.3.8 Thermal Foldback
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 TPS923654 Boost, 12V Input, 1A Output, 12-piece WLED Driver With Analog Dimming
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Input Capacitor Selection
          3. 8.2.1.2.3 Output Capacitor Selection
          4. 8.2.1.2.4 Sense Resistor Selection
          5. 8.2.1.2.5 Other External Components Selection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 TPS923654 Buck-Boost, 24V Input, 2A Output, 4-piece WLED Driver with PWM Dimming
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Inductor Selection
          2. 8.2.2.2.2 Input Capacitor Selection
          3. 8.2.2.2.3 Output Capacitor Selection
          4. 8.2.2.2.4 Sense Resistor Selection
          5. 8.2.2.2.5 Other External Components Selection
        3. 8.2.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.5.3 Hybrid Dimming

The TPS92365x family supports a unique hybid dimming function to maximize the dimming performance, especially when both high dimming frequency and high dimming ratio are needed. The hybrid dimming mode is enabled when the ADIM/HD pin is always low and the EN/PWM pin is configured by a PWM input signal. A first falling edge at EN/PWM pin is necessary to enter hybrid dimming mode and then the EN/PWM pin can be always high for 100% duty cycle. The device exits hybrid dimming mode once a rising edge appears at ADIM/HD pin. Once the device exits hybrid dimming mode, the device can only work either in PWM, analog or flexible dimming mode until the device is disabled and renabled.

In the hybrid dimming mode, the LED current is regulated by the analog dimming at high brightness level (12.5% to 100%) and by the PWM dimming at low brightness level (0% to 12.5%), respectively. At high brightness level, the internal voltage reference, VREF, changes in proportion to the duty cycle of the PWM input signal at the EN/PWM pin with 8-bit resolution. At low brightness level, VREF stays unchanged and an internal PWM generator is enabled. Thus, the LED is turned on and off corresponding to the on and off of the internal PWM signal of which the frequency and the duty cycle are configured by the PWM input signal at the EN/PWM pin. In addition, the internal PWM signal has a 0.4% hystersis response when the PWM input duty cycle changes between increasing and decreasing. The detailed hybrid dimming behavior is illustrated in the below figure.

TPS923652 TPS923653 TPS923654 TPS923655 Hybrid Dimming Figure 7-3 Hybrid Dimming