US Patent 11372501 Control method and control circuit for fingerprint sensing

A control method for fingerprint sensing includes following steps. First fingerprint brightness codes detected in reference with a ramp-counting variable varying in a full range are received during a pre-scanning phase. An initial code is generated according to a distribution of the first fingerprint brightness codes. The initial code is applied to the ramp-counting variable during a normal scanning phase for detecting second fingerprint brightness codes in reference with the ramp-counting variable varying in a partial range. A boundary of the partial range is determined according to the initial code. A control circuit is also disclosure.