Light emitting element drive device and mobile apparatus

• US 8,970,117 B2
• Filed: 01/31/2011
• Issued: 03/03/2015
• Est. Priority Date: 02/01/2010
• Status: Expired due to Fees

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Sumisaki, Katsushi, Taniguchi, Toshihiko, Yoshino, Tsunemi, Amari, Satoshi
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Chan, Wei
• Application Number:
  US13/518,044
• Publication Number:
  US 20120262073A1
• Time in Patent Office: 1,492 Days
• Field of Search: 315/250, 315/291, 315/224, 315/159, 315/240, 320/167
• US Class Current: 315/159
• CPC Class Codes: G03B 15/0447 Energy sources; Batteries; Capacitors
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0503 Built-in units
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H04N 23/651 for reducing power consumption by affecting camera operations, e.g. sleep mode, hibernation mode or power off of selective parts of the camera
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A light emitting element drive device of the present invention includes a light emitting element; a drive unit for driving the light emitting element; an electricity storage element capable of storing electric power; a battery power supply capable of supplying electric power to the electricity storage element; and a boost chopper circuit having an inductor, for boosting voltage by opening and closing a switching element. The drive unit is switchable between three states: a storing state in which electric power from the battery power supply is stored in the electricity storage element; a first discharging state in which the electric power stored in the electricity storage element is supplied to the light emitting element; and a second discharging state in which electric power from the battery power supply is boosted by the boost chopper circuit and is supplied to the light emitting element.

Claims

1. A light emitting element drive device comprising:

a light emitting element;

a drive unit for driving the light emitting element;

an electricity storage element capable of storing electric power;

a battery power supply capable of supplying electric power to the electricity storage element; and

a boost chopper circuit having an inductor, for boosting voltage by opening and closing a switching element,

wherein the drive unit is switchable between;

a storing state in which electric power from the battery power supply is stored in the electricity storage element, wherein electric power from the battery power supply is prevented from being supplied to the light emitting element;

a first discharging state in which the electric power stored in the electricity storage element is supplied to the light emitting element, wherein electric power from the battery power supply is prevented from being stored in the electricity storage element; and

a second discharging state in which electric power from the battery power supply is boosted by the boost chopper circuit and is supplied to the light emitting element, wherein electric power from the battery power supply is prevented from being stored in the electricity storage element.

2. The light emitting element drive device of claim 1, wherein the drive unit in the first discharging state causes the electric power stored in the electricity storage element to be boosted by the boost chopper circuit and to be supplied to the light emitting element.

3. The light emitting element drive device of claim 2, wherein the boost chopper circuit in the first discharging state changes time of opening and closing the switching element so as to uniformize voltage applied to the light emitting element.

4. The light emitting element drive device of claim 1, wherein the drive unit further includes a current limit unit for limiting a level of a current output from the battery power supply in the storing state in which electric power from the battery power supply is stored in the electricity storage element and in the second discharging state.

7. A mobile apparatus including the light emitting element drive device of one of claim 1.

9. The light emitting element drive device of claim 2, wherein the drive unit further includes a current limit unit for limiting a level of a current output from the battery power supply in the storing state in which electric power from the battery power supply is stored in the electricity storage element and in the second discharging state.

10. The light emitting element drive device of claim 3, wherein the drive unit further includes a current limit unit for limiting a level of a current output from the battery power supply in the storing state in which electric power from the battery power supply is stored in the electricity storage element and in the second discharging state.

5. A light emitting element drive device comprising:

a light emitting element;

a drive unit for driving the light emitting element;

first and second electricity storage elements capable of storing electric power;

a battery power supply capable of supplying electric power to the drive unit and the electricity storage elements; and

a control unit supplied by the battery power supply with electric power, for controlling the drive unit,

wherein the drive unit is switchable between;

a storing state in which the electricity storage elements and the light emitting element are parallel-connected to the battery power supply and in which electric power supplied from the battery power supply is stored in the electricity storage elements wherein electric power from the battery power supply is prevented from being supplied to the light emitting element; and

a discharging state in which the first electricity storage element and the light emitting element are series-connected to the battery power supply and in which the electric power stored in the first electricity storage element is supplied to the light emitting element while the electric power stored in the second electricity storage element is supplied to the control unit.

11. A mobile apparatus including the light emitting element drive device of claim 5.

6. A light emitting element drive device comprising:

a light emitting element;

a drive unit for driving the light emitting element;

first and second electricity storage elements capable of storing electric power; and

a battery power supply capable of supplying electric power to the drive unit and the electricity storage elements,

wherein the drive unit is switchable between;

a storing state in which the electricity storage elements and the light emitting element are parallel-connected to the battery power supply and in which electric power supplied from the battery power supply is stored in the electricity storage elements wherein electric power from the battery power supply is prevented from being supplied to the light emitting element;

a first discharging state in which the battery power supply, the first electricity storage element and the light emitting element are series-connected and in which the electric power stored in the first electricity storage element is supplied to the light emitting element; and

a second discharging state in which the battery power supply, the second electricity storage element and the light emitting element are series-connected and in which the electric power stored in the second electricity storage element is supplied to the light emitting element.

8. A mobile apparatus comprising:

the light emitting element drive device of claim 6;

an optical system for collecting light; and

an imaging element for receiving the light collected by the optical system,

wherein the optical system has an automatic focusing mechanism, and

wherein the drive unit switches to the first discharging state so as to cause the light emitting element to emit light as auxiliary light for automatic focusing and switches to the second discharging state so as to cause the light emitting element to emit light as flash light for imaging.