SLVAFQ9 January   2024 TPS92201

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Why Building Automation Need IR LED in Video Doorbell, Security Cam System
  5. 2Basic Dimming Knowledge – PWM and Analog Dimming
    1. 2.1 Analog Dimming
    2. 2.2 PWM Dimming
  6. 3Video Doorbell, Security Cam Industry Common Design for IR LED
    1. 3.1 External PWM Low Pass Filter
    2. 3.2 Industry Application Advantage and Disadvantage
  7. 4TPS92201 Design in Video Doorbell, Security Cam
  8. 5Summary
  9. 6References

3.1 External PWM Low Pass Filter

Figure 3-1 is the common design in Cam and doorbell that is usually seen in the industry. Customers usually use a PWM dimming IC and connect an external resistor and capacitor as a low pass filter and adjust the current. Adjusting the current makes the design as analog dimming.

GUID-20231123-SS0I-MRDL-HQD0-PT8MDKRGQFXJ-low.svgFigure 3-1 Current Comment Design
GUID-20231123-SS0I-SC9D-1QCC-MZPTBBPFK88W-low.svgFigure 3-2 Design Schematic