May 1, 2007
Companies in the electronics industry continually strive to reduce costs and bring new, innovative products to market faster than ever before in order to be successful in today's competitive business climate. As electronic products become faster and more complex, so does the process of designing and verifying those new products. The aerospace and defense, consumer electronics, computers and peripherals, communications, semiconductor and automotive industries are facing pressure to reduce test costs by optimizing capital investments and by reducing test times. This is driving the development of automatic test equipment (ATE) systems that have faster system throughputs, use industry computer I/O and take up less floor space.
Power supplies are a key component of nearly every test set-up, and often multiple power supplies are needed to run today's complex ATE systems. But all power supplies are not equal. An ATE system may use several powers supplies, each having different power and performance requirements. For example, some power supplies may need to be fast, be able to change voltages quickly and provide high accuracy, while other power supplies only need to meet simple DC power requirements.
Currently, when several power supplies of various performance levels are needed in a system, the only way to do it is to use multiple power supplies. If the power supplies come from different manufacturers, test engineers have the additional hassle of working with multiple companies to purchase and support the power supplies. They also face the challenge of developing test programs using power supplies with different I/O and programming options. The use of multiple power supplies from different manufacturers also means that test engineers are not able to utilize rack space efficiently because of incompatible mechanical packages.
Recognizing that power supplies can have a significant impact on the performance and flexibility of ATE systems, Agilent introduced a new generation of system-ready power supply components that are designed to meet new application demands. This backgrounder will explore how Agilent's new power system provides convenient size, increased processing speeds and modular flexibility to help test system designers meet the challenges of today's ATE system requirements.
Transforming ATE System Design with the New Agilent Modular Power System
The advanced capabilities of Agilent's new N6700 modular power system (MPS) are transforming how test system designers power their ATE systems. The Agilent MPS provides three key benefits: small size, fast processing speeds and flexibility.
The Agilent MPS is the industry's first 1U (1.75" or 45 mm) high, multiple-output DC power supply targeted at automated test applications. Within that small rack space, the Agilent MPS modular power system gives test system designers the flexibility to configure a 1- to 4-channel DC power system at up to 300W per channel that is optimized to meet specific test requirements. Test system integrators can mix and match any of the available 22 modules in any of the three MPS mainframes to create a 1U-high DC power system. Where speed and accuracy are needed, test engineers can invest in high-performance outputs, or test engineers can purchase basic performance outputs for simple DC power requirements starting at $1000 per output. For many ATE systems, speed is critical to keeping test costs low, and the Agilent MPS provides an industry-leading command processing time of less than 1 millisecond.
The Agilent MPS also enables test engineers to use the PC standard software environment they are comfortable with - whether it is textual, graphical or a spreadsheet - and it provides the choice of PC standard I/O to simplify test system set-up. The new platform architecture offers a system-ready power supply optimized for both price and performance in either stand-alone operation, or for increased throughput in a more complex test system environment.
Maximizing Rack Space
In order to simplify test system design and keep capital costs low, test system designers need power supplies that consume a minimal amount of rack space. The Agilent MPS uses an advanced switch mode power supply technology to squeeze up to 4, 300W outputs into 1U. With output noise of 5 mV peak-to-peak and programming speeds of just a few milliseconds, the Agilent MPS offers the performance of a linear power supply with the small size typical of switching power supplies. In addition, because the Agilent MPS has no top or bottom air vents, other instruments can be mounted directly above or below it.
Industry-Leading Speeds Expand Power Supply Capabilities
The Agilent MPS has an industry-leading command processing time of less than 1 millisecond. This fast command processing time yields a speed improvement 10 to 50 times over other programmable power supplies and can significantly impact overall ATE system throughput.
Speed is taken a step further with the N6750 family of high performance, autoranging DC power modules and the N6760 family of precision DC power modules. To provide test system designers maximum system throughput, these modules offer output programming speeds (e.g., the time it takes the output to go from one voltage to another after receiving a command) that are so fast they are unlike a power supply.
FIGURE 1: N6700 DC power module output programming speeds compared to voltage changes
The Agilent MPS uses an advanced digital control system in place of a series of analog control loops to achieve these speeds. The digital control can dynamically adjust the drive circuitry within the DC power module to rapidly raise its output. When programming down in voltage, a digitally controlled down programming circuit acts like an internal electronic load to rapidly pull down the output voltage.
These speeds allow the Agilent MPS to be more than just a DC power supply that provides static voltage to the design-under-test (DUT). The Agilent MPS can also act like a stimulus device such as a power arbitrary waveform generator for testing semiconductors, motors, actuators, avionics and other devices that require both power and a rapidly changing voltage.
Built-in Measurements Broaden Range of Applications
All Agilent MPS modules feature a built-in digital multi-meter (DMM) to measure the power supply's voltage and current. Traditionally, while the power supply controls voltage on the DUT, the current into the DUT is typically unknown and therefore requires measurement. In order to measure the current entering the DUT, a DMM or shunt is inserted into the current path, breaking it. This complicates system wiring, and can introduce noise and measurement error. By building voltage and current measurements into the power supply, measurements can easily be made right at the source, eliminating wires, noise pickup and inaccuracies. In addition, the built-in measurements can be calibrated as part of the power supply calibration, thereby increasing measurement accuracy.
In addition to DC measurements made by the built-in DMM, the Agilent MPS offers an optional built-in digitizer to make measurements on time-varying voltage and current in the DUT. This capability is important for applications such as digital phones, which draw current from the battery in pulses as the transmitter pulses on and off. Most digital devices (PDAs, laptops, cameras, etc.) and battery powered devices (automotive electronics, consumer electronics, etc.) pulse on and off to conserve battery power.
Typically, an oscilloscope is used to make these kinds of time-varying measurements, although using an oscilloscope can be challenging. Current measurements with an oscilloscope require a shunt that interrupts the current path, a current probe, or some kind of current transducer such as a Hall Effect sensor. All of these options introduce additional wiring and system complexity, and require calibration to achieve an accurate measurement.
The Agilent MPS, when configured with optional high-speed test extensions, provides an oscilloscope-like digitizer built into the power module to capture voltage and current measurements of 4096 points at 50,000 measurements per second. It also includes the ability to capture dynamic information about the current flowing into the DUT. For applications such as design validation of battery powered digital devices, it allows designers to better understand the current drain on DUT batteries and optimize DUT power management during normal DUT operation and in DUT standby mode.
Autoranging to Test a Wider Range of DUTs
The Agilent MPS gives test system designers even more flexibility by providing autoranging capabilities on the N6750 family of high-performance, autoranging DC power modules and the N6760 family of precision DC power modules. The autoranging capability provides maximum output power at any output voltage up to 50V. This allows one power supply to do the job of several power supplies because its operating range covers low-voltage, high-current as well as high-voltage, low-current operating points.
For example, the Agilent N6751A high performance, autoranging DC module, rated at 50V, 5A and 50W can operate at:
- 10V at 5A (=50W)
- 20V at 2.5A (=50W)
- 33.3V at 1.5A (=50W)
- 50V at 1A (=50W)
- or any combination in-between that equals 50W.
Therefore, due to its extended voltage and current range, this 50W autoranging power supply can produce voltage and current combinations similar to a 250W non-autoranging power supply.
The flexibility of autoranging is useful when the DUT operates over a wide range of voltages, when the ATE system needs to test a wide range of DUTs, or when margin is needed because the ATE power supply must be selected before final DUT power requirements are determined.
Flexible Input/Output Options
The Agilent N6700 is the first power supply to provide universal serial bus (USB 2.0), 10/100 Base-T Ethernet (LAN) and general-purpose interface bus (GPIB) interfaces as standard features. This allows quick and simple connectivity to a PC, other instruments in a test system, or to a network for access across an engineering workgroup. The Agilent N6700 can also be operated remotely from any browser by connecting to its built-in Web-page for control and monitoring of power supply operations.
Flexibility to Maximize Power, Performance and Price
The Agilent MPS offers three performance levels to ensure that engineers can configure a power supply that meets specific application needs, including:
- ATE applications in which the power supply plays a critical role. The Agilent N6750 family of high-performance, autoranging DC power modules provide low noise, high accuracy and fast programming speeds.
- ATE applications such as semiconductor testing. The Agilent N6760 family of precision DC power modules provides precise control and measurements in the milliamp and microampere region.
- Basic DC applications. The Agilent N6730 and N6740 families of DC power modules provide programmable voltage and current, measurement and protection features at a very economical price, making these modules suitable to power the DUT or to provide power for ATE system resources, such as fixture control.
Agilent's new MPS platform is ideal for developers of complex test applications and systems who require faster processing speeds and more flexibility for their measurement requirements. The Agilent N6700 1U high, multiple-output programmable DC power supply system enables test system integrators to optimize performance and power to match their test needs, and helps to dramatically drive down the overall cost of test system development.
|Related links for more information|
|Press Release:||Agilent Technologiesí N6700 Modular Power System extends industry-leading processing speeds, autoranging output, advanced measurement capabilities into higher power for ATE applications
|For more information:||www.agilent.com/find/N6700|