MULTI-SWITCH SYSTEM FOR INPUTTING MULTI-KEYS

摘要

A multi-switch system for inputting multi-keys includes: a (N+1) number of resistance which are connected in series; an N number of switches which are respectively positioned between a node which is not connected to a second resistance between two nodes of both ends of a first resistance and a node which is adjacent to a (N+1)^th resistance between two nodes of both ends of each of a first to an N^th resistance among the (N+1) number of resistance; and a capacitor which is connected to the (N+1)^th resistance in series among the (N+1) number of resistance. The multi-switch system for inputting multi-keys of the present invention determines which switch among the N number of switches is in a turned on state by detecting the voltage of the first node which is a node between the (N+1)^th resistance and the capacitor. According to a desired embodiment of the present invention, the provided multi-switch system for inputting multi-keys can be cost effective by having a fewer number of required I/O terminals and being composed by a simple circuit. [Reference numerals] (AA) Level detector