Input device with ghost key suppression

摘要

An input device with ghost key suppression includes a switch module, a comparator, an exchange unit, a bias voltage resistor, and a processing module. The switch module includes a plurality of strobe lines, a plurality of sense lines, and a plurality of switch units. Each of the switch units has a switch and a resistor connected in series between a corresponding one of the strobe lines and a corresponding one of the sense lines. The comparator is configured for comparing a signal received at an input end thereof with a reference signal for generating the comparison signal. The exchange unit is electrically connected to the sense lines and the comparator, and is operable in response to a control input for making and breaking electrical connection between each of the sense lines and the input end of the comparator. The processing module controls operation of the switch module and the exchange unit based on the comparison signal.

主权项

1. An input device comprising:
a switch module including a plurality of strobe lines, a plurality of sense lines, and a plurality of switch units, each of said switch units having a switch and a resistor connected in series between a corresponding one of said strobe lines and a corresponding one of said sense lines, said switch of each of said switch units being operable at a selected one of conducting and non-conducting states; a comparator including a first input end, a second input end for receiving a reference signal, and an output end for outputting a comparison signal, said comparator being configured for comparing a signal received at said first input end with the reference signal for generating the comparison signal; an exchange unit electrically connected to said sense lines and said first input end of said comparator, and operable in response to a control input for making and breaking electrical connection between each of said sense lines and said first input end of said comparator; a bias voltage resistor including a first end and a second end, said first end being electrically connected to said first input end of said comparator, said second end being configured for receiving a first voltage level; and a processing module that is electrically connected to said strobe lines, said comparator and said exchange unit,
wherein said processing module is configured for outputting a plurality of strobe signals respectively to said strobe lines, the reference signal to said second input end of said comparator, and the control input to said exchange unit, said processing module being further configured for receiving the comparison signal from said output end of said comparator;wherein said processing module is configured to set at least a part of the strobe signals, the reference signal and the control input such that the comparison signal is able to indicate whether said switch of at least one of said switch units is at a conducting state;wherein, upon determination by said processing module that the comparison signal indicates said switch of at least one of said switch units is at a conducting state, said processing module is further configured to set at least a part of the strobe signals, the reference signal and the control input such that the comparison signal is able to indicate whether said switch of at least one of said switch units that are electrically connected to a selected one of said sense lines is at a conducting state;wherein, upon determination by said processing module that the comparison signal indicates said switch of at least one of said switch units that are electrically connected to the selected one of said sense lines is at a conducting state, said processing module is further configured to set at least a part of the strobe signals, the reference signal and the control input such that the comparison signal is able to indicate whether said switch of said switch unit that is electrically connected to the selected one of said sense lines and a selected one of said strobe lines is at a conducting state.