Multiplexer Leakage Current Detection and Compensation

Abstract

A multiplexed input / output (I / O) system detects leakage currents on selected input channels. The system includes a leak detection multiplexer coupled to provide an output selected from one of a plurality of input channels. In addition, the leakage detection multiplexer provides the measured leakage current associated with the selected input channel as part of the output. Based on the detected leakage current, a determination may be made as to whether the detected leakage current is detrimental to the multiplexer output. Furthermore, the detected leakage current can be used to compensate the output provided by the multiplexer to account for the effect of the presence of the leakage current on the selected channel.

Description

technical field [0001] The present invention relates to a multiplexer, and more particularly to a multiplexer structure for detecting leakage current between input channels. Background technique [0002] A multiplexer is a device that provides an output selected from multiple inputs. Multiplexers are beneficial because they allow multiple devices to share more expensive resources such as analog-to-digital converters. In this way, a single ADC can be used for multiple devices as opposed to having a separate ADC for each device. [0003] Control (e.g., turn off and on) the multiple switches (e.g., metal-oxide-semiconductor devices, optocouplers, etc.) employed by the multiplexer to select the desired input (e.g., channel) to switch between multiplexers The output of the multiplexer is provided. Ideally, the switch when off provides complete isolation between each of the plurality of channels. In fact the switch allows a small amount of current to leak between the channels ...

AI Technical Summary

Problems solved by technology

However, factors such as temperature and device-to-device potential (i.e., intentionally or unintentionally keeping the input devices of a multiplexer at significantly different potentials) alone or in combination increase the The leakage current associated with the switch

[0005] In many applications, such as process control applications, even small changes in the signal integrity provided by the multiplexer can cause significant application errors

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