0 Practical Tips You Need to Know About Your Power Products Simple ways to improve your operation and measurement capabilities
Use remote sensing to compensate for load-lead effects Tip 1 When your power supply leaves the factory, its regulation sense terminals are usually connected to the output terminals. This limits the supply’s voltage regulation abilities, even with very short leads. The longer the leads and the higher the wire gauge, the worse the regulation gets (Figure 1). Compare the output impedance of a well-regulated 10 A supply, which might have an output impedance of 0.
Increase safety with remote disable feature Tip 2 Remote disable offers a safe way to shut down a power supply to respond to some particular operating condition or to protect system operators (in response to a cabinet door being opened unexpectedly or someone pushing a panic button, for instance). +5 V To microprocessor RI Com DFI From microprocessor Remote inhibit (RI) is an input to the power supply that disables the output when the RI terminal is pulled low (Figure 1).
Eliminate noise from low-level measurements Tip 3 Noise in low-level measurements can come from a number of different sources, and it’s easier to eliminate noise than to filter it. Check these noise sources: 1. Power supply Starting with a low-noise supply is naturally a great way to keep noise out of your measurements. Linear power supplies have lower commonmode noise currents and generally operate at low frequency.
Tip 4 Use down programming to increase test speed Under light or no load conditions, a power supply’s output capacitor discharges slowly. If you’re using the supply as a static voltage source, this is not problematic, but when you’re making tests at varying voltage levels, slow discharge means slow tests. Down programming circuits in power supplies rapidly decrease the output voltage, reducing discharge times by hundreds of milliseconds.
Tip 5 Simplify setup with autoranging power supplies With bench and rack space at a premium, having the ability to produce a wide range of voltage and currents with one power supply is beneficial. Applications that require many voltage and current combinations require many power supplies or a very large power supply to span the largest voltage and current combination. For example, a dc/dc converter is tested under several voltage and current combinations at about the same power level.
Connect power supplies in series or parallel for higher output Tip 6 + Power supply #1 – EM + Power supply #2 – E1 + Power supply #3 – E2 EL RL Connecting two or more power supplies in series (Figure 1) provides higher voltages, but observe these precautions: Connecting two or more power supplies in parallel (Figure 2) provides higher currents, but again, observe these precautions: • Never exceed the floating voltage rating of any of the supplies.
Tip 7 Simplify battery drain analysis with analysis tools To adequately specify the power source for products that exhibit pulsed and dynamic current loading (such as digital cellular phone and hard drives), you need to evaluate both the peak and dc averages current draws. You could use an oscilloscope to monitor a shunt or a current probe, but this approach raises issues with voltage drops, ground loops, common mode noise, space, and calibration.
Tip 8 Characterize inrush current with an ac power source/analyzer The inrush current characteristics of ac-dc switch mode power supplies vary with the turn-on phase of the voltage cycle. Usually, these power supplies have input capacitors that draw high peaks of inrush current as they charge from the rectified ac line at turn-on.
Tip 9 Use a power supply to measure DUT supply current Accurately measuring DUT supply currents above 10 A is beyond the range of the typical DMM in ammeter mode. You could use an external shunt and the DMM’s voltage mode, but using the power supply itself is a better solution. Many supplies include an accurate measurement system, including a shunt. Current (with the internal shunt) or voltage measurements at the DUT can be as simple as sending a MEAS command to the power supply.
Create dc power waveforms with list mode Tip 10 Instead of using a DAC or arbitrary waveform generator to drive a power supply to create dc power waveforms, consider using a single power product with list mode. List mode lets you generate complex sequences of output changes with rapid, precise timing which may be synchronized with internal or external signals. They contain up to 512 individually programmed steps and can be programmed to repeat themselves.
Power products that do more and less demand Agilent Technologies’ “one-box” philosophy means we pack more and more capability into the power products themselves, in some cases giving you a rack’s worth of capability in a single box. By offering more, these products demand less from you—fewer instruments, less rack space, simpler test setups, and lower cost of ownership.
Power you can count on year after year We’ve been a leader in the power products business for more than half a century because engineers like you know they can count on Agilent performance, reliability and value. Even our least-expensive dc supplies offer low ripple and noise with tight load and line regulation. Our high precision products give you the exact power levels you need, with accurate readback measurements to match. Plus, every product you see here is covered by a one-year warranty.
Power products that do more and demand less Dynamic measurement dc supplies Solar array simulator (SAS) Electronic Loads The Agilent 66300 series are the first power supplies with instantaneous peak measurement capability, so you no longer need a scope or high-speed digital voltmeter to test devices that draw pulsed current. The Agilent E4350-series SAS simulates the output characteristics of a satellite’s solar panels.
ac power source/analyzers From avionics to uninterruptible power supplies, customers are demanding products that can use power efficiently while handling all kinds of ac line disturbances. To make sure your products meet these growing expectations, test them with the Agilent 6800-series ac power source/analyzers.
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