In a military world, victory can be held in the details. The more we know about our opponent’s movement, their mechanical and technological capabilities, and environmental conditions can sometimes be the edge needed for triumph – or at least survival.
The source of military data capture, therefore, must be reliable. Data sensors need to be versatile and scalable. A variety of military sensor technologies are used to fulfil this critical need. Sensors monitor the presence of threats, the activities of enemy forces, the conditions of the weather, the nature of the environment, the state of a piece of equipment during its operation, and whether biological or chemical changes have occurred. They are included in systems like drones, missiles, satellites, rockets, marine systems, combat and reconnaissance vehicles, and more.
Given the vast number of physical or chemical parameters that can be measured, not to mention the wide range of measurement settings required, you can imagine that there are all kinds of sensors already in existence. And more are on the way.
In fact, the military sensor market is expected to grow to $42.76 billion by 2027 .
“Military sensor and signal processing technologies are going through revolutionary improvements and offer to bring big enhancements to applications like radar, electronic warfare (EW), signals intelligence (SIGINT), high-performance edge computing, and anti-submarine warfare (ASW),” John Keller reports for Military & Aerospace Electronics.
Consider the need for situational awareness and intelligence on the typical fighting platforms:
- Aerial (fighter aircraft, helicopters, support aircraft, unmanned aerial aircraft)
- Land (armored ground and support vehicles, unmanned ground vehicles, soldiers, and operating bases),
- Munition (rockets, missiles, guided ammunition, artillery systems, and torpedoes),
- Naval (combat and support ships, submarines, unmanned sea vehicles ),
For each of these environments, sensors are essential to the performance of many critical applications.
Owing to the wide variety of uses, environments, and innovation, their construction is not fixed but comes in all shapes and sizes. Typical components include the hardware that determines its physical appearance and survivability, software with data processing and analytics, and the cybersecurity attribute to secure the data.
Rapid advances in technology in multiple fields have created opportunities for transforming novel applications to practical use. The result? Sensors that are more accurate, smaller, more lightweight and more robust than their predecessors. And since innovation continues as we speak, more sensors are on the way with defense forces everywhere finding more ways to use them.
Given the sensitivity of their application in measuring data, to providing complex controls, these sensors need to function when needed in harsh environments and a gamut of situations.
Uses for Sensors in Military
Sensors are key to missile defense operations and perform critical functions throughout the intercept cycle: early warning, discrimination, tracking, and kill assessment.
Some of the categories into which sensor systems are classified include:
- Surveillance and monitoring
- Intelligence and reconnaissance
- Communication and Navigation
- Target Recognition
- Electronic Warfare
- Command and Control
The Unique Electronic Component Requirements of Military Sensors
A point of failure for these types of devices is their electronic components that are susceptible to power surges.
As you know, any electronic device with complex circuitry that is built to last should have some circuit protection.
These sensor units are often exposed to harsh environments and must face the elements, leaving them at the mercy of lightning strikes and the effect of close lightning strikes.
High-performance components make sure the sensors stand up to the most unfavourable conditions – extreme weather, complete darkness, fog or dust, etc. But the electronic components need to be reliable and function normally throughout.
The key to such systems comes from small, yet powerful integrated circuitry
TVS diodes are desirable protection devices for many sensor scenarios in the battlefield. They are characterized by low capacitance (when signal integrity is important} and fast responses to overvoltages. More importantly, they do not degrade in the course of protecting against energetic events like MOVs do for instance. TVS diode operation involves the clamping of overvoltages in order to protect the load in parallel.
MDE Semiconductor, Inc. manufactures a wide range of TVS devices for military application. Tested rigorously to meet military standards, our products have found use in many devices today.
Protecting The Components of Military Sensors
Sensors typically consist of 4 main components:
- Sensing unit
- Power unit
The sensing unit usually consists of a sensor and a converter to transform analogue signals from the sensor to a digital signal. The digital signal is sent to the processor. The sensing unit optimizes for both processing logic or digital signals.
Whatever the parameter being measured or the mechanism of its measurement, the sensor operates to transfer the signal.
The transceiver receives and transmits the data signals. Its communication subsystem is equipped with a receiver to communicate with the outside world and any neighboring nodes.
Transceivers are designed to be robust, however external protection from transient events like current and voltage surges due to electrostatic discharge will ensure longevity and the entire sensor performs as it should.
The processor’s job is to make the billions of computations required to translate data within signals from the transceiver into usable data. According to recent reports from Military & Aerospace Electronics, new technology coming available this past year have made processors more effective than ever before.
“Artificial intelligence (AI) and machine learning for so-called smart sensors, open-systems industry standards like the Sensor Open Systems Architecture (SOSA), new architectures for field-programmable gate arrays (FPGAs), information security, fast networking over copper and optical interfaces, and fast A/D and D/A conversion- with these enhancements, systems designers can process more data than ever before; reduce, size, weight, and power consumption (SWaP); free-up slots in the embedded computing enclosure for additional capabilities; and place high-performance sensor and signal processing as close to receiver antennas as possible in SWaP-constrained applications like unmanned vehicles.”
The final component, the power unit, is often a battery. Yet even a component as seemingly simple as a battery has to pull heavy duty for military applications. Sensor batteries need to manage a trade off between full functionality and power-saving optimization. To preserve battery life in the field, the components often switch on and off regularly.
Therefore, both the hardware and software design must optimize efficient energy usage, e.g reducing energy through data compression for radio transmission but then requiring processing high power on the other end.
A major challenge with sensor devices is power consumption, which impacts performance. One way to design with this challenge in mind is to utilize TVS diode operation within the system.
Protecting a Sensor System from Electrical Transients
Surge pulses in a printed circuit board (PCB) can be destructive when the spike exceeds the absolute maximum (abs max) ratings of the integrated circuit. Therefore protection is critical. Depending on a variety of factors, including design and operational mechanisms, protection might be required on interface lines.
It is also important that any protective devices do not interfere with the normal operation of the sensor system and its electric components. The protection devices should remain idle under these conditions. A TVS diode acts as an open circuit so that signals and data are fed through without errors. Although, it must be borne in mind that a TVS has a small leakage current. But the protective devices must activate when a transient event occurs. Below is a brief description of how tvs diodes operation in a protected circuit will help correct selection.
- When a TVS diode activates, it limits the voltage across the protected circuit. TVS diodes are typically placed in parallel to the circuit.
- MDE Semiconductor, Inc. produces a range of TVS diodes for different voltage, power, or form factors, as well as designed in many different configurations.
TVS Diode Operation
When the operating voltage exceeds a certain value [should we include a specific value here?] the TVS diode junction avalanches, and the overvoltage is diverted away from the protected circuit and shunted through the TVS diode. When the overvoltages disappear and things revert to normal, the TVS diode automatically resets.
Reasons for temporary voltage spikes that can last for a few microseconds or less include lightning or minor arcing. It’s not hard to imagine the damage that high voltage spikes of a few thousand volts can do to a miniaturized integrated circuit, especially one with a voltage rating of a few hundred volts.
The TVS diode operation can be unidirectional or bidirectional. A unidirectional diode can handle large peak currents for a short time and act as rectifiers in the forward direction. They can also provide protection for both negative and positive transient events in DC power applications.
Bi-directional TVS diodes are ideal for AC power applications and have less capacitance then an equivalent unidirectional device.
A TVS diode is characterized by its:
- Reverse standoff voltage/working voltage: This is the normal operating voltage of the diode. At this value or below, it conducts a negligible amount of electricity and acts as an open circuit.
- Reverse breakdown voltage: the TVS diode begins to conduct electric current at this voltage because of the avalanche effect. The breakdown voltage is associated with/ corresponds to a specified test current (1mA or 10mA).
- Peak pulse current: Currents above this value will damage the TVS diode. Datasheets provide a peak pulse current for a specific transient waveform (e.g., 8/20 ųs, 10/1000 ųs)
- Clamping voltage: This refers to the maximum voltage drop across the TVS diode for a given peak pulse current
For sensing applications where signal integrity is important, choose a diode with minimal capacitive loading while not sacrificing clamping performance.
MDE Semiconductor, Inc. Offers a Variety of Circuit Protection Solutions Used in Military Grade Smart Sensor Systems.
A MAX40-30A can be utilized to provide a means of protecting a filter and the load connected to the filter. This TVS can be utilized at both the input and output of the filter to minimize the effect of impulses on the filter and load.
* * *
Sensors are ubiquitous in the military. They provide measuring, monitoring, and execution capabilities for the defense ecosystem. They are critical for delivering critical, time-sensitive, high-security data that, in turn, helps our military outmaneuver its adversaries.
From tiny, hidden sensors for covert carrying by individual soldiers to all-weather environmental sensors, sensor circuitry calls for lightweight, miniaturized materials that must use power efficiently.
TVS diode operation guards these complex circuits against destructive energy spikes. Proper TVS diode operation is ideal for repeated power surges since they don’t depreciate with each event. Additionally, their operation allows for/ affords lower clamping voltages than is possible with other methods.
MDE Semiconductor, Inc. designs and manufactures circuit protection devices used in sensor applications that are RoHs and REACH compliant.
*Featured image from International Defense, Security and Technology website