Patent ID: 9524069
Filing Date: 2016-12-20
CPC Classification: H03K,H03M

Claim Text:
1. A method for operating a capacitive touch keypad, the method comprising: receiving a touch by a conductive object to one or more keys of the keypad, in which the keypad has a plurality of keys that each have a separate capacitive key electrode; precharging a pseudo-randomly selected set of key electrodes a number (M) of iterations while the keyboard is being touched; producing a sense voltage for each iteration by coupling all of the key electrodes to a reference capacitor; producing a 1-bit sense measurement for each iteration by comparing the sense voltage to a reference voltage to form a set of M 1-bit sense measurements; and determining each touched key location by applying a modified binary iterative hard threshold (BIHT) algorithm to the set of M 1-bit sense measurements, in which only the non-zero locations of the solution are monitored in each iteration.