Keithley 3185 Ensuring PwrSply Perf free download

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Number 3185 Ensuring that Power Supply Application Note Performance Meets Your Requirements Series Details beyond the specifications that can impact how well the power supply meets your requirements Most engineers feel that they understand power supplies very well. Power supplies are considered one of the simplest V instruments since they tend to be a one-function, DC device VMAX which outputs a controlled voltage. But of course there is much more to power supplies. While a power supply's specifications adequately describe performance for most applications, cost, time, and human resource limitations prevent the specification of all aspects of a power supply's (or any instrument's) performance. You will want to understand the power envelope I IMAX of the power supply so that it will be able to deliver the power at the voltage and current parameters that you need for your Figure 1a. Rectangular power supply envelope. Any current level can be work. For development, characterization, and testing of circuits delivered at any voltage. that generate or measure low level signals, then the selection of the design topology of the power supply and investigation into V its common mode current can be a necessity so that the power supply does not interfere with circuit performance. Similarly, if V1MAX you are developing a device with multiple isolated circuits, then you will want your power supply not to degrade the isolation of your device. When you use your power supply as an accurate V2MAX voltage source for testing your circuit over its operating voltage range or as a calibrating source, you will want to ensure that you can obtain the specified accuracy of the supply at the input to I I1MAX I2MAX the circuit-under-test. Applications such as these will require a more detailed investigation into a power supply's characteristics. Figure 1b. Multi-range output. This characteristic allows higher voltages at lower currents and higher currents at lower voltages. Understand the Power Envelope of the Power Supply V The most significant decision is ensuring that sufficient power is available to energiz