| abstract |
An electronic device capable of increasing the braking torque applied to an electric power generator without causing a significant reduction in electric power generated by the electric power generator. The electronic device, which may be embodied in an electronically controlled mechanical clock, includes an electric power generator for converting mechanical energy transmitted from a spring via a wheel train to electrical energy, and a rotation controller for controlling the rotation period of the electric power generator. The rotation controller includes switches capable of connecting two terminals of the electric power generator in a closed-loop state, a chopping signal generator for generating two or more types of chopping signals which are different in duty ratio or frequency for use in a strong braking operation, and chopping signal selector that selects one of the chopping signals, wherein, in the strong braking operation, the selected chopping signal is applied to the switches so as to control the electric power generator in a chopping fashion. The strong braking operation is performed in one of two modes such that a higher priority is given to generation of electric power or the braking torque depending on the mode, thereby achieving an increase in the braking torque of the electric power generator without causing a significant reduction in the voltage generated by the electric power generator. |