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

1.1 Why Building Automation Need IR LED in Video Doorbell, Security Cam System

In Infrared LED illumination sub-system cameras with day and night vision, the system features a cut filter control, LED dimming, ambient light measuring, and ballasting for the current of each IR LED string. Ballasting is an alternative for driving multi-string LED arrays with a single string LED driver while maintaining uniform illumination under low-light conditions.

PARAMETERSPECIFICATIONS
Power supply voltage2.5 approximately 5.5V
IR LED current

Max 1.5A

IR LED minimum15mA
IR LED current matching<5%
IR LED wavelength

800 approximately 980nm

Operation temperature-40 °C to 85 °C
Figure 1-1 Simply Block Diagram in IR LED system
GUID-F717DA59-28D6-4434-B597-9BFB946326A0-low.pngFigure 1-2 TPS92201 EVM Board
GUID-FF3ED7BF-93DB-4B8C-AE13-28F2FB3B3B62-low.pngFigure 1-3 TPS92201 EVM Schematic