by Neal Kurfiss and Michael Jackson
Earlier blogs in this series showed how to use ADI Trinamic solutions to design stepper motors that enable surveillance cameras to move quietly (to avoid detection) and smoothly (to avoid jerky video streams). Now the series switches focus to consider camera connectivity and power, starting with this blog which discusses how industrial Ethernet offers a 2-for-1 solution for both requirements.
Balancing the Burden of Expectations on Camera Suppliers and Installers
Security and Surveillance camera suppliers typically don’t sell directly to end consumers, instead opting to use a network of installers. While this approach offers advantages, it limits suppliers’ ability to ensure installers follow recommended guidelines. Inevitably, in the desire to reduce costs by finishing a job quickly, or else due to a lack of training, some installations end up being sub-optimal and this has the potential to negatively impact camera performance and therefore (somewhat unfairly), the camera supplier’s reputation. Mitigating this requires balancing the burden of expectations on both the supplier and installer:
What are the Connectivity Challenges?
For surveillance and security cameras, connectivity “downtime” is much more than a simple inconvenience – it can be the difference between life and death. Therefore, cameras must be able to operate reliably in even the harshest of environments, and to do so they need a robust communications protocol, capable of transporting video data reliably.
What are the Power Challenges?
As camera complexity increases, design details and power solutions need to be adaptable. For example, if the camera housing requires grounding, galvanic isolation may be required while on the other hand, designs that don’t require isolation can have a more compact form factor. In addition, high frame-rate video streams and always-on infrared LEDs can consume a significant amount of power. These requirements are further complicated by the fact that single cable cameras are now the standard.
Figure 1 Connectivity and power challenges
Industrial Ethernet: A 2-in-1 Connectivity and Power Solution
Analog Devices’ ADIN1300 is a gigabit industrial Ethernet physical layer transceiver (PHY) in a small footprint of 6 mm × 6 mm, 40-lead LFCSP package, offering low power consumption (330 mW) and latency (only 290 ns to transmit and receive over an RGMII interface). For lower data rate applications, the ADIN1200 10/100 Mbps industrial Ethernet PHY comes in an even smaller 5 mm × 5 mm, 32-lead LFCSP package and consumes only 139 mW of power, while also providing low 300ns latency over MII.
Figure 2 Analog Devices’ ADIN1300 and ADIN1200 industrial Ethernet PHYs
These transceivers have been subjected to extensive EMC and robustness testing to meet the most demanding industrial standards including:
Their proven ability to survive harsh industrial environments makes them an excellent choice to withstand the worst conditions likely to be experienced by security and surveillance cameras.
Power Over Ethernet (PoE) Power Options
Apart from robust and reliable data connectivity, another significant advantage of using industrial Ethernet is that it can also be used to transport power to end devices. Analog Devices offers three different PoE solution options to power all components including the motor, camera, and illuminator as well as the downstream (lower voltage) PMIC input.
Power Option 1:
Where non-isolated power is an acceptable option, the LT4293 + LTC7801 controllers provide a 60 W IEEE 802.3bt power delivery (PD) solution that can withstand overvoltage spikes up to 100 V. This makes it incredibly robust, while the absence of large transformers makes it exceptionally compact.
Power Option 2:
This solution offers added electrical isolation to enable case-grounding and other hard-wired connections. Here the LT4295 manages the PD interface and voltage regulation. Flyback design options for the LT4295 can further reduce circuit complexity.
Power Option 3:
Camera designs with a lower power burden on the 12 V line can be simplified even further. The LT4269-1 uses a passive diode bridge serving as a PD controller and voltage rectifier in a 25W IEEE 802.3at PD solution.
Partner with Experts You Can Trust
PoE is not a ‘one size fits all’ solution. Security and surveillance camera designers can benefit by partnering with Analog Devices, which has the system domain expertise and expansive technology portfolio to provide optimal power and connectivity solutions for a multitude of camera designs. The next blog in this series will look at how the unique features of GMSL can be exploited in this application.
