A/D chip input voltage limiting protection circuit

Abstract

The invention discloses an A / D chip input voltage limiting protection circuit, and belongs to the technical field of data acquisition of high-reliability computer systems. The circuit is composed of an operational amplifier, a diode and a resistor, and by ingeniously using the negative feedback characteristic and saturated output characteristic of the ideal operational amplifier, the one-way conduction characteristic of the diode, the voltage reduction characteristic of the resistor and the like, the A / D chip input voltage limiting function is achieved. According to the circuit, by selecting different resistance values, arbitrary amplitude precise limiting of input voltages at the front end of an A / D chip can be achieved, and the positive voltage and negative voltage bidirectional limitingcan be achieved. When the input voltages of the A / D chip are within the limiting range, the limiting circuit does not influence an original circuit. The method is simple, practical and low in cost.

Description

technical field [0001] The invention relates to an A / D chip input voltage limiting protection circuit, which belongs to the technical field of data acquisition of highly reliable computer systems. Background technique [0002] In the design of high-reliability circuits, the reliability of the chip must be considered. The reliability of the chip is affected by many factors, and electrical stress is one of them. The voltage of each input interface of the chip is required to be limited within the recommended value, so as to avoid reducing the reliability of the chip due to exceeding the recommended value, resulting in reduced service life or even damage. The voltage conversion input terminal of the A / D chip usually requires a fixed range, and the multi-channel switching method is usually used to complete the acquisition of multiple analog inputs. In order to prevent the A / D The reliability of the D conversion chip is reduced or damaged. In high reliability applications, the A / ...

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Problems solved by technology

[0003] The commonly used TVS tube limiting method has the limiting voltage value limited by the design voltage of the selected TVS tube, and cannot adjust the limiting amplitude value arbitrarily and cannot complete the demand for accurate limiting. In order to overcome these problems, the present invention designs a An A / D chip input limiter protection circuit, which can perform arbitrary amplitude, bidirectional and precise limiter on the input voltage

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