Remote sensing is often used when a system's power supply must deliver a voltage which must remain within carefully designated range at the load, while the load is located at a distance from the source ("distance" in this context may be only a few inches) and the amount of current is large—often on the order of several amps. As a result, the actual voltage delivered will be out of spec, and lower than it was at the supply.
It is an especially challenging situation for low-voltage, high-current applications. If designer does not plan for the combination of current and distance, then the dynamic nature of the load coupled with the parasitic resistance of the power path may affect the operation of the power supply. To overcome this problem, the remote-sensing technique is often used.
This article discusses design considerations for remote sensing, including power-plane shortages, component placement, parasitic resistance, and potential oscillations. Also, a practical example demonstrates the effectiveness of a high-frequency bypass capacitor for mitigating oscillations associated with remote sensing.
Click to read the application note "Remote sensing for power supplies" which originally appeared in the Texas Instruments Analog Applications Journal, 2Q 2012 (May).
About the author
Tiger Zhou is a Senior Applications Engineer at Texas Instruments.
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