Lighting Circuit and Luminaire

摘要

A lighting circuit includes an input unit, an output unit, a rectifying circuit, first and second switching circuits, a dimming signal generating circuit, and first and second control units. The input unit is connected to a control device that outputs an alternating-current voltage. The output unit is connected to a light-emitting unit. The rectifying circuit converts the alternating-current voltage into a rectified voltage. The first switching circuit converts the rectified voltage into a first voltage with a first switching element. The second switching circuit converts the first voltage into a second voltage with a second switching element and outputs the second voltage to the output unit. The dimming signal generating circuit generates a dimming signal. The first control unit controls the first switching element. The second control unit controls the second switching element.

主权项

1. A lighting circuit comprising:
an input unit electrically connected to a control device that converts a first alternating-current voltage subjected to conduction angle control into a second alternating-current voltage having a different effective value and outputs the second alternating-current voltage; an output unit electrically connected to a light-emitting unit, the light-emitting unit including a first terminal, a second terminal, and a light-emitting element electrically connected between the first terminal and the second terminal and configured to emit light when an electric current flows from the first terminal to the second terminal; a rectifying circuit electrically connected between the input unit and the output unit and configured to rectify the second alternating-current voltage input via the input unit and convert the second alternating-current voltage into a rectified voltage; a first switching circuit electrically connected between the rectifying circuit and the output unit, including a first switching element, and configured to convert the rectified voltage into a first voltage according to switching of the first switching element, the first switching element including a first electrode, a second electrode, and a first control electrode for switching a first state in which an electric current flows between the first electrode and the second electrode and a second state in which an electric current flowing between the first electrode and the second electrode is smaller than the electric current in the first state, and the first electrode and the second electrode being connected to the light-emitting element in parallel; a second switching circuit electrically connected between the first switching circuit and the output unit, including a second switching element, and configured to convert the first voltage into a second voltage of a direct current according to switching of the second switching element and output the second voltage of the direct current to the output unit, the second switching element including a third electrode, a fourth electrode, and a second control electrode for switching a third state in which an electric current flows between the third electrode and the fourth electrode and a fourth state in which an electric current flowing between the third electrode and the fourth electrode is smaller than the electric current in the third state, and the third electrode and the fourth electrode being connected to the light-emitting element in series; a dimming signal generating circuit electrically connected between the input unit and the rectifying circuit or between the rectifying circuit and the first switching circuit and configured to generate a dimming signal corresponding to the conduction angle control on the basis of one of the second alternating-current voltage and the rectified voltage; a first control unit electrically connected to the first control electrode and configured to control the switching of the first switching element and set an effective value of an electric current flowing to the input unit to be equal to or larger than a predetermined value; and a second control unit electrically connected to the second control electrode and the dimming signal generating circuit and configured to control the switching of the second switching element and set the second voltage to a voltage value corresponding to the dimming signal.