
Verify Thousands of Devices Every Week With System Power Supplies
Key takeaways:
- System power supplies can provide tens of kilowatts with high efficiency and low heating losses for high-powered automotive, defense, and aerospace use cases.
- Modular system power supplies allow customers to upgrade their output power in the future when their loads increase.
- A system power supply's stable output is essential for thorough corner-case and stress testing using automated test equipment.
- The programmability and fast settling times of system power supplies enable them to emulate complex real-world scenarios.
Modern electronic systems are so complex that thoroughly testing a single component manually can take several days. But manufacturers need to routinely test and verify thousands of components every week if their businesses are to remain viable.
The only practical solution is to automate the entire testing process, preferably end-to-end. Automated test equipment (ATEs) are the workhorses of these initiatives, allowing companies to assemble standardized interoperable test equipment and program them for their needs.
The power supplies in these ATEs are critical to ensuring reliable tests. They're called system power supplies, and in this article, we are going to dive into what they do.
What is a system power supply in automated test equipment?
Fig 1. Automated test equipment
Automated test equipment are purpose-built assemblies of test and measurement instruments to automate the testing of specific electronic components or systems during their design and verification testing or production testing.
A block diagram of a typical ATE is shown above. Some characteristics of ATEs include:
- the use of racks for efficient use of floor space
- the use of rack-mountable and programmable versions of instruments like signal generators, digital multimeters, and power supplies whose form factors follow standardized dimensions and have their measurement and output ports at the back instead of the front like benchtop versions do
- special fixtures to position and connect to the devices under test (DUTs)
- extensive use of data acquisition systems (DAQs) for scaling up the number of measurement points and data recordings
- automated test plans using purpose-built ATE software
A system power supply is a specialized direct current power supply designed to facilitate automated testing. Let's look at some of the key features of system power supplies that make them suitable for mounting in ATEs.
Key features of system power supplies
The following capabilities of these DC power supplies make them perfect for use in ATEs:
- Programmability: Their output behaviors can be finely controlled either through simple output lists or more complex programs using the Standard Commands for Programmable Instruments (SCPI) protocol.
- Output stability: These instruments are designed to keep their outputs exceptionally stable, even in the presence of line or load fluctuations.
- Accuracy and precision: These instruments deliver voltages and currents with both high accuracy and precision.
- Autoranging: These supplies typically support autoranging, which is the ability to automatically adjust their voltage and current limits to match the demands of the load.
- Fast command processing time: They respond quickly to programming commands and change their states quickly in response to those commands.
- Fast settling times: System power supplies are designed for fast settling times so there's no lag in their responses to programming commands.
- High power efficiency: Although system power supplies like the N8900 can deliver up to 15 kilowatts (kW), they still manage to maintain their efficiency near 90%, which is essential to prevent heating losses.
- Connectivity: System power supplies support standard ATE connectivity buses like the Peripheral Component Interface (PCI) eXtensions for Instrumentation (PXI) and the local area network (LAN) eXtensions for Instrumentation (LXI).
- Stackability: Multiple system power supplies can be interconnected to combine their power. For example, N8900s have digital port connectors that enable many of them to work together to supply as much as 100 kW in total.
- Safety protections: System power supplies have reliable safety protections to keep the DUTs and the rest of the ATE safe.
In the following sections, we explore some of these aspects and their importance in more detail.
How does a system power supply handle different voltage and current demands?
ATE power supplies can handle different voltage and current demands through various strategies:
- Using modular power supplies: Modular power supplies can be expanded by inserting additional power supply modules. The modules can be independently configured to supply different voltages and currents to different DUTs.
- Using multiple channels: Some models offer multiple independent channels that can supply different voltages and currents.
- Using programmability: Another strategy is through programmable outputs that can be finely tuned for each DUT.
Why is the efficiency of an ATE system power supply important?
ATEs are often used for long-term functional and stress testing to examine how well DUTs perform under different conditions. So minimal heat losses, good cooling, and good temperature control are essential, mainly for stability and safety reasons.
High efficiency also offers bonus benefits like:
- lower electricity consumption and its environmental benefits
- reduction in operational costs since thermal management can be simpler
- reduction in the space taken up by test equipment since less heat means instruments can be placed closer together
- increased lifespan of the power supply and its components due to lower thermal stresses
What is power factor correction (PFC) and how does it impact efficiency?
Fig 2. Misalignment between voltage and current waveforms is solved by power factor correction.
Power factor correction improves the efficiency of the system power supply by aligning the voltage and current waveforms, especially under long-term inductive loads. PFC drastically reduces the wasteful reactive power demand, leading to higher effective efficiency, lower energy costs, and reduced stress on the electrical infrastructure.
How does system power supply contribute to system reliability?
In ATEs, power supply reliability directly influences the consistency and repeatability of test results. Features such as self-diagnostic routines, protections, and robust designs ensure that downtime is minimal, the integrity of test data is preserved, and DUT performance is not misinterpreted.
How does a system power supply handle transient events and fluctuations in input power?
ATE power supplies are designed to swiftly respond to transient events and input power fluctuations to prevent inaccuracies in testing outcomes.
One strategy is to use very high-frequency switched-mode designs. System power supplies typically use switched-mode designs for high power efficiency and compactness. By switching at very high frequencies, they're able to quickly detect fast transients. Their correction circuits, which use high-quality capacitors, are then able to compensate to keep the output stable.
Fast correction circuits and comprehensive protection mechanisms safeguard the DUT from potential damage due to power anomalies, which is crucial when testing sensitive or high-value components.
What are the protection features in a system power supply?
System power supplies include extensive safety features to protect the DUT, itself, and the other test equipment. These features include:
- Overcurrent and overvoltage protection: They always keep the current and voltage under safe limits to prevent damage to the DUT or ATE components. If an anomaly is detected, the power supply automatically shuts down or limits the output to a safe level.
- Thermal protection: This protects the power supply and its surroundings from overheating, which can occur under heavy loads or faulty conditions.
- Short-circuit protection: This feature reduces safety, damage, and downtime risks.
What are the key considerations when designing a system power supply?
The design considerations for an ATE system power supply include:
- the maximum voltage and current it must support
- tradeoffs between a linear and switched-mode architecture
- fast, precise load regulation
- stable line regulation in its alternating current to direct current converter circuit to protect from fluctuations in the input voltage
- remote connectivity
- programmability
- real-time monitoring
What are the factors to consider when selecting a system power supply for a specific application?
Pay attention to these functions when choosing a system power supply for an application:
- Voltage and current requirements of the DUT: The power supply must match or exceed the DUT's voltage and current demands to ensure stable power under all test conditions.
- Programmability: For flexibility in automated testing, the power supply should offer precise remote control over the voltage and current levels. It should support fast and wide dynamic changes in power during testing.
- Support for test automation: The power supply must support complex test sequences through testing scripts.
- Precision and/or throughput: ATEs for design and verification tests typically need high precision, while those for production testing need high throughput more than precision.
- Ability to simulate complex scenarios: Check the ability of the system power supply to programmatically reproduce various operational conditions, such as low battery or voltage drops, to test the DUT's response under different power scenarios.
- Repeatability: Ensuring every DUT is tested under precisely the same conditions enhances the reliability of test results. Programmability and device stability help to maintain this consistency across multiple test runs and setups.
- Stability and low noise: The supply must provide stable and low-noise output to avoid interfering with the test results, especially critical for testing sensitive electronics like semiconductors.
- Modularity: A modular power supply consists of multiple power supply modules that can be individually configured to meet specific power requirements of the testing setup, including power levels, measurement accuracy, precision, and more. This modular design allows for a versatile and scalable solution, enabling users to customize the power supply according to the diverse and changing needs of different electronic devices under test.
What are some trends in system power supply technology?
Advances in ATE system power supply technology, such as improved digital interfaces and software control, offer enhanced programmability, precision, and efficiency. Digital power supplies facilitate complex and automated test sequences with improved accuracy and repeatability. The benefits of these advances include:
- more sophisticated testing capabilities
- high performance
- finer adjustment of output parameters
- better monitoring of the system status
- smart adaptable power supplies that dynamically adjust to changing system demands and predict maintenance needs
Applications of ATE system power supplies
System power supplies are critical to any domain where ATEs are extensively used.
These include:
- Defense: Reliability is a major focus of defense applications like radar systems, electronic warfare systems, marine electronics, and vehicle systems. The testing is rigorous, sometimes taking years. ATEs are extensively used in defense applications to improve confidence in these systems.
- Avionics: ATEs are used extensively to verify and qualify the complex avionics aboard both commercial and military aircraft.
- Satellite systems: ATEs are used to test the ground station systems and onboard equipment of military and commercial satellites.
- Automotive systems: High-power system power supplies like the 5-15 kW N8900 series are used for automated testing of electric vehicles and hybrids. They're also used to qualify infotainment systems, advanced driver assistance systems, and other internal systems of vehicles.
- Telecommunications: Telecom companies are using ATEs to validate 5G components in consumer electronics and network equipment.
- Semiconductor testing: Companies like Intel, AMD, and Nvidia use ATEs extensively to rigorously check computer components like central processing units (CPUs), graphics cards and graphical processing units (GPUs), field-programmable gate arrays, and more.
- Consumer electronics: Device manufacturers use ATEs to bulk test their devices and components, such as testing embedded processors, motherboards, hard drives, solid-state drives (SSDs), and other PC components.
System power supplies ensure reliability
In this article, we explored the features of system power supplies used in automated test equipment.
Keysight offers ATE system power supplies with various power specifications to suit different use cases.
Contact us for recommendations on your automated test equipment.