SLUUCI5A July   2021  – November 2021 TPS92519-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Warnings and Cautions
  4. 3Description
    1. 3.1 Typical Applications
    2. 3.2 Features
    3. 3.3 Connector and Test Point Description
    4. 3.4 Electrical Performance Specifications
  5. 4Test Setup
    1. 4.1 Input Supplies and LED Load Connections
    2. 4.2 Switching Frequency Selection
    3. 4.3 Analog Dimming Using IADJx
    4. 4.4 PWM Dimming Using UDIMx and PWM Test Points
  6. 5Performance Data and Typical Characteristic Curves
    1. 5.1 Efficiency
    2. 5.2 Analog Dimming
    3. 5.3 PWM Dimming
    4. 5.4 PWM Dimming Waveforms
  7. 6Schematic
  8. 7TPS92519EVM-169 PCB Layout
  9. 8Bill of Materials
  10. 9Revision History

4.3 Analog Dimming Using IADJx

Analog Dimming for each channel is controlled by IADJ1 (TP10) and IADJ2 (TP4) test points or by using the resistor divider attached to 5 V. The voltage on the IADJx pin sets the regulated LED current by the following equation.

Equation 1.

By default, RFB2x is not loaded and therefore needs an external power supply to set the VIADJx setpoint. J1 and J2 are not loaded by default.

Figure 4-4 Channel 1IADJ Using External Supply
Figure 4-5 Channel 2 IADJ Using External Supply

There is a placeholder for resistor divider and RFB2x has to be calculated for the desired ILEDx. See Figure 4-6 for the circuit diagram and equation. R1 controls the voltage for IADJ2 and R5 controls the voltage for IAdJ1. See Figure 4-7.

Figure 4-6 Setting IADJx Using On-Board Resistor Divider
Figure 4-7 IADJ Using Resistor Divider