SNVAA88 December   2023 LM51581-Q1 , TPS1H000-Q1 , TPS92642-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2System Description
    1. 2.1 Dual Cable Concept
    2. 2.2 Single Cable Concept
  6. 3Camera Module Design with Single Coaxial Cable Connection
    1. 3.1 Power-Over-Coax Filter
    2. 3.2 Boost Converter
    3. 3.3 High-Side Switch
    4. 3.4 Buffer Capacitor
    5. 3.5 LED Driver
    6. 3.6 Serializer
    7. 3.7 Design Steps
  7. 4Test Results
    1. 4.1 LED and PoC Voltage Waveforms
    2. 4.2 Margin Analysis Program Result
    3. 4.3 Differential Supply Noise Level
    4. 4.4 Test Cases
  8. 5Summary
  9. 6References

3 Camera Module Design with Single Coaxial Cable Connection

Figure 4-8 shows a reference test design of a remote camera module with IR illumination and single coaxial cable connection. The module can be divided into two subsystems: An imager subsystem and the IR illumination subsystem. The imager subsystem includes the serializer and the 1.8V power supply for the serializer. Both subsystems are powered over the coaxial cable through the PoC filter. As the IR LEDs are driven with large current pulses the illumination subsystem includes additional components beside the LED driver to reduce the impact from the pulsing LEDs on other parts of the system, especially the high-speed FPD-Link communication.

The high peak current pulse driving the IR LEDs is transformed to a lower peak current on the input side. This allows to control the peak current on the coaxial cable.

GUID-20230928-SS0I-FWXW-VQ21-XWDGK6XDQSTD-low.svg Figure 3-1 Block Diagram of DMS Camera Module With Single Coax Connection

The individual functional blocks and design considerations are discussed in the following sections.