Light source unit and lighting fixture

Patent metadata

Field	Value
Publication number	US-2016242249-A1
Application number	US-201615011739-A
Country	US
Kind code	A1
Filing date	Feb 1, 2016
Priority date	Feb 12, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

The light source unit includes a light source circuit including N (N≧3) pairs of a light source group including one or more solid light emitting elements and a constant current circuit connected in series with the light source group to keep, constant, current flowing through the light source group, a full-wave rectification circuit for performing full-wave rectification on AC voltage, and a control circuit. The first pair is connected to the full-wave rectification circuit. The k-th (2≦k≦N) pair is connected in parallel with the constant current circuit of the (k−1)-th pair so that the light source groups of the k-th and (k−1)-th pairs are in series. The control circuit terminates operations of the constant current circuits of the N pairs or limits currents flowing through the light source groups of the N pairs in response to detection of light or a signal.

First claim

1 . A light source unit, comprising:
a light source circuit including N pairs of a light source group including one or more solid light emitting elements and a constant current circuit connected in series with the light source group to keep, constant, current flowing through the light source group, where N is an integer equal to or greater than 3; a full-wave rectification circuit which includes a first output end and a second output end and is configured to perform full-wave rectification on AC voltage to cause DC voltage between the first output end and the second output end; and a control circuit including a detector configured to detect light or signal from an external source, a first pair of the N pairs being connected between the first output end and the second output end of the full-wave rectification circuit, a k-th pair of the N pairs being connected in parallel with the constant current circuit of a (k−1)-th pair of the N pairs so that the light source group of the k-th pair and the light source group of the (k−1)-th pair are in series, where k is an integer equal to or greater than 2 and equal to or smaller than N, and the control circuit being configured to, when the detector detects the light or signal, terminate operations of constant current circuits of the N pairs or limit current flowing through light source groups of the N pairs.

2 . The light source unit according to claim 1 , wherein:
in each of the N pairs, the constant current circuit includes a switching element connected to the light source group and is configured to keep current flowing through the switching element constant; and the k-th pair is connected to the switching element of the constant current circuit of the (k−1)-th pair.

3 . The light source unit according to claim 2 , wherein:
the control circuit is configured to, when the detector detects the light or signal, turn off the switching elements of the constant current circuits of the N pairs.

4 . The light source unit according to claim 2 , wherein:
each of the switching elements includes a control terminal and is configured to change current flowing through the switching element according to an electric potential at the control terminal; and the control circuit is configured to adjust electric potentials at the control terminals of switching elements of the constant current circuits of the N pairs so that current flowing through the light source groups of the N pairs decreases with an increase in an intensity of the light detected by the detector.

5 . The light source unit according to claim 2 , wherein:
the full-wave rectification circuit is configured to cause the DC voltage between the first output end and the second output end so that an electric potential at the first output end is higher than an electric potential at the second output end; each of the switching elements includes a control terminal and is configured to change current flowing through the switching element according to an electric potential at the control terminal; the control circuit includes a switching part electrically connected between the control terminals of the switching elements of the constant current circuits of the N pairs and the second output end; and the control circuit is configured to, when the detector detects the light or signal, control the switching part to terminate the operations of the constant current circuits of the N pairs or limit the current flowing through the light source groups of the N pairs.

6 . The light source unit according to claim 1 , wherein:
the full-wave rectification circuit is configured to cause the DC voltage between the first output end and the second output end so that an electric potential at the first output end is higher than an electric potential at the second output end; the control circuit includes a switching part electrically connected between a constant current circuit of the first pair and the second output end; and the control circuit is configured to, when the detector detects the light or signal, turn off the switching part.

7 . The light source unit according to claim 1 , wherein:
the full-wave rectification circuit is configured to cause the DC voltage between the first output end and the second output end so that an electric potential at the first output end is higher than an electric potential at the second output end; the control circuit includes a switching part electrically connected between a constant current circuit of the first pair and the second output end; and the control circuit is configured to, when the detector detects the light or signal, control the switching part to limit current flowing through the light source groups of the N pairs.

8 . The light source unit according to claim 1 , further comprising a substrate having a front surface and a rear surface,
the light source groups of the N pairs being on the front surface of the substrate, and the detector being on the rear surface of the substrate.

9 . A lighting fixture, comprising:
the light source unit of claim 1 ; and an attaching member for holding the light source unit.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Hiramatsu Akinori
• Ido Shigeru
• Ueda Daisuke
• Kido Hiroshi

Classifications

• H05B45/44 Primary

  with an active control inside an LED matrix · CPC title

• F21K9/00

  Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers · CPC title

• H05B45/10

  Controlling the intensity of the light · CPC title

• F21V23/003

  the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array · CPC title

• H05B45/50 Primary

  responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits · CPC title