SLUUCQ0A may   2023  – june 2023 TPS922052 , TPS922053 , TPS922054 , TPS922055

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Warnings and Cautions
  6. 3Description
    1. 3.1 Typical Applications
  7. 4Test Setup
    1. 4.1 Connector Description
    2. 4.2 Input/Output Connection
  8. 5Typical Characteristics Curves and Waveforms
    1. 5.1 Efficiency
    2. 5.2 Line Regulation
    3. 5.3 Load Regulation
    4. 5.4 Analog Dimming Performance
    5. 5.5 PWM Dimming Performance
    6. 5.6 Hybrid Dimming Performance
    7. 5.7 Flexible Dimming Performance
  9. 6Schematic
  10. 7Layout
  11. 8Bill of Materials
  12. 9Revision History

Hybrid Dimming Performance

Figure 5-14, Figure 5-15 show the hybrid dimming waveforms at 10%, and 20% duty cycles, respectively. Input voltage is 48 V, with 7 white LEDs in series used as load. The full-scale LED current is set at 4 A. The ADIM/HD pin is always low. The frequency of the input PWM signal at the PWM/EN pin is 20 kHz.

GUID-20230219-SS0I-DSN3-77L1-4FSCSMNML1WH-low.pngFigure 5-11 Waveforms at 10% Duty Cycle, 20 kHz Hybrid Dimming
GUID-20230219-SS0I-QZ8K-TDDC-MWQQ51BQZ7XJ-low.pngFigure 5-12 Waveforms at 20% Duty Cycle, 20 kHz Hybrid Dimming

When the hybrid dimming is enabled, the LED current is regulated by the analog dimming at high brightness level (12.5% ~ 100%) and by the PWM dimming at low brightness level (0%~12.5%).

Figure 5-13 gives the test result of linearity of hybrid dimming, in comparison with the theoretical value. Input voltage is 48V, with 7 white LEDs in series used as load. The full-scale LED current is set at 4 A. The frequency of the input PWM signal at the PWM/EN pin is 20 kHz.

GUID-20230220-SS0I-038W-HHH9-MXHRFTZV8KR5-low.pngFigure 5-13 Hybrid Dimming Linearity