Device for detecting the state of a switch

摘要

A device for detecting the state of a switch. The device includes a detection circuit which delivers a signal of specified value (Vpullup) when the value of an electrical quantity (RSw) characterizing the state of the switch is less than a threshold called the lower threshold (Rclosed) and/or a signal of different value when the value of the electrical quantity is greater than a threshold different from the lower threshold, called the upper threshold (Ropen). The disclosed embodiments also concern flight control systems, in which the device is implemented, and the aircraft including the systems.

主权项

1. A device for detecting the state of a switch, including a switch and a feed circuit of said switch, the device comprising:
a detection circuit which delivers at least one of:
a first signal of a first specified value when the value of an electrical quantity characterizing the state of the switch is any value less than a lower threshold value at a terminal of the detection circuit; anda second signal of a second specified value, different than the first value of the first signal, when the value of said electrical quantity is any value greater than an upper threshold value, different from the lower threshold value at the same terminal of the detection circuit as the first signal; the device further comprising said feed circuit and an adjustment circuit that includes a voltage divider having resistors, a voltage delivered by the adjustment circuit to the detection circuit being made dependent on a resistance of the switch, the adjustment circuit allowing for reading the resistance of the switch through the voltage divider, the feed circuit, and the voltage delivered to the detection circuit; and wherein at least one of:
a voltage of the feed circuit, andvalues of the resistors of the voltage divider, are adjusted in such a way to provide sufficient current to clean a contact of the switch based on the reading, and wherein the detection circuit includes a hysteresis circuit which delivers a first output-voltage value for an input voltage less than a first voltage threshold and a second, different output-voltage value for an input voltage greater than a second voltage threshold, and the first output-voltage value is determined based on a following expression:VHyHigh=AR5⁢R6R4⁢R5+R4⁢R6+R5⁢R6and the second output-voltage value is determined based on a following expression:VHyLow=AR5⁢R6R4⁢R5+R4⁢R6+R5⁢R6+BR4⁢R5R4⁢R5+R4⁢R6+R5⁢R6 wherein VHy High denotes the first voltage threshold, VHy Low denotes the second voltage threshold, A denotes a first constant value, B denotes a second constant value, R4 denotes a first resistance value of the hysteresis circuit, R5 denotes a second resistance value of the hysteresis circuit, and R6 denotes a third resistance value of the hysteresis circuit.