Encoder and light source of encoder

• Main Authors: Kawatoko, Osamu, Kobayashi, Hirokazu
• Format: Patent
• Language: English
• Published: 04.02.2020
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; GENERATION; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; SYSTEMS FOR STORING ELECTRIC ENERGY; TARIFF METERING APPARATUS; TESTING

An encoder includes a light source. A booster circuit boosts a power supply voltage output by a battery, and outputs the boosted voltage. The voltage is applied to one end of a light-emitting diode. A driver circuit is inserted between another end of the light-emitting diode and a ground, the driver circuit controlling current flowing through the light-emitting diode. A voltage detector circuit detects a voltage between the light-emitting diode and the driver circuit. A control circuit causes the booster circuit to boost the power supply voltage when the voltage is lower than the power supply voltage; stops the boosting performed by the booster circuit when the voltage is equal to the power supply voltage; and controls the driver circuit such that, after the voltage reaches a predetermined value, current flows to the light-emitting diode.