US 12,443,147 B2
Electronic watch and electronic watch control method
Takuya Tanabe, Shiojiri (JP)
Assigned to SEIKO EPSON CORPORATION, (JP)
Filed by SEIKO EPSON CORPORATION, Tokyo (JP)
Filed on Jan. 18, 2023, as Appl. No. 18/155,981.
Claims priority of application No. 2022-006173 (JP), filed on Jan. 19, 2022.
Prior Publication US 2023/0229114 A1, Jul. 20, 2023
Int. Cl. G04C 3/14 (2006.01); H02P 8/12 (2006.01); H02P 8/34 (2006.01)
CPC G04C 3/14 (2013.01) [H02P 8/12 (2013.01); H02P 8/34 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An electronic watch comprising:
a hand;
a stepping motor including a coil, the stepping motor being configured to drive the hand;
a drive circuit configured to drive the stepping motor;
a controller configured to provide a drive pulse to the drive circuit to control the drive circuit;
a current detection circuit configured to detect a current value flowing through the drive circuit; and
a random access memory configured to store polarity information of the drive pulse,
wherein the controller is configured to:
delete the polarity information stored in the random access memory when the electronic watch is initialized;
store initialized polarity information into the random access memory after the polarity information stored in the random access memory has been deleted;
output a polarity detection pulse to the drive circuit based on the initialized polarity information stored in the random access memory, the polarity detection pulse not causing the stepping motor to rotate by one step;
perform a polarity determination processing of determining whether a polarity of the stepping motor and the initialized polarity information match based on the current value detected by the current detection circuit in response to the output of the polarity detection pulse; and
change the initialized polarity information when the polarity of the stepping motor and the initialized polarity information do not match.