State detecting circuit, key-press detector, and musical instrument

摘要

A state detecting circuit has a first switch circuit connected to a first selection line and a second switch circuit connected to a second selection line. The first switch circuit includes two switches, and performs an arithmetic operation of ON/OFF states of the switches and a selection signal. Thus, since one switch circuit performs an arithmetic operation using ON/OFF states of the two switches, the number of selection lines and the number of parts can be reduced.

主权项

1. A state detecting circuit comprising:
a plurality of switch circuits, each of the plurality of switch circuits comprising at least one switch which switches between an ON state and an OFF state in response to a change in a physical amount which is a target of detection, each of the plurality of switch circuits configured to output a state signal which changes according to an ON/OFF state of the switch included in the switch circuit itself, wherein the plurality of the switch circuits include one or a plurality of three-state switch circuit comprising two switches in which thresholds of the physical amount at which the switch switches between the ON state and the OFF state are different from each other, configured to invert the state signal when the physical amount exceeds a smaller one of the thresholds of the two switches, and further configured to invert the state signal when the physical amount exceeds a larger one of the thresholds of the two switches, wherein the plurality of switch circuits include at least one two-state switch circuit having a threshold between the thresholds of the two switches of the three-state switch circuit, and configured to invert the state signal when the physical amount exceeds the threshold.