Abstract: A power conversion device includes: a DC/DC converter including a conversion circuit; and a control circuit that detects a first voltage at an output terminal, a first current flowing through the conversion circuit, and a second voltage at an input terminal, obtains information indicating a target output voltage and a predetermined voltage, and performs calculations to emit a PWM signal for operating the conversion circuit. The control circuit performs: a first calculation for calculating a target current for approximating the first voltage to the target output voltage; a second calculation for calculating a first duty ratio for approximating the first current to the target current; a third calculation for calculating a second duty ratio based on the predetermined voltage and the second voltage; and a fourth calculation for calculating a driving duty ratio of the PWM signal using the first and the second duty ratios to control the first voltage.

Abstract: A power conversion device includes: a DC/DC converter including a conversion circuit; and a control circuit that detects a first voltage at an output terminal, a first current flowing through the conversion circuit, and a second voltage at an input terminal, obtains information indicating a target output voltage and a predetermined voltage, and performs calculations to emit a PWM signal for operating the conversion circuit. The control circuit performs: a first calculation for calculating a target current for approximating the first voltage to the target output voltage; a second calculation for calculating a first duty ratio for approximating the first current to the target current; a third calculation for calculating a second duty ratio based on the predetermined voltage and the second voltage; and a fourth calculation for calculating a driving duty ratio of the PWM signal using the first and the second duty ratios to control the first voltage.

Abstract: Provided is a watch, including: an exterior case having electroconductivity; an operating member having electroconductivity, which is inserted into the exterior case through an opening formed through the exterior case, and which is configured to accept an operation performed by a user; and an electrostatic motor including: an electret substrate having an electret surface on which electret films being electrically charged are provided; a counter substrate, on which electrodes to be arranged so as to be opposed to the electret films are provided; and a rotary shaft configured to rotate the electret substrate and the counter substrate relative to each other, wherein the operating member and the exterior case are electrically continuous with each other via a conduction path formed so as to avoid overlapping with the electret surface in plan view.

Abstract: Provided is a watch, including: an exterior case having electroconductivity; an operating member having electroconductivity, which is inserted into the exterior case through an opening formed through the exterior case, and which is configured to accept an operation performed by a user; and an electrostatic motor including: an electret substrate having an electret surface on which electret films being electrically charged are provided; a counter substrate, on which electrodes to be arranged so as to be opposed to the electret films are provided; and a rotary shaft configured to rotate the electret substrate and the counter substrate relative to each other, wherein the operating member and the exterior case are electrically continuous with each other via a conduction path formed so as to avoid overlapping with the electret surface in plan view.