Light emitting element drive apparatus and portable apparatus using the same
First Claim
1. A light emitting element drive apparatus wherein a plurality of light emitting elements of different drive voltages required for emitting light are connected in parallel and one or more light emitting elements among the plurality of light emitting elements are driven, comprising:
- a plurality of drive circuits connected to corresponding light emitting elements of said plurality of light emitting elements and driving the corresponding light emitting elements with luminances based on set values;
a decision circuit for deciding a drive voltage value required for the highest light emission among one or more light emitting elements driven to emit light based on drive states of said plurality of drive circuits; and
a power supply circuit for supplying a drive voltage to said plurality of light emitting elements in response to the decision result of said decision circuit,wherein said power supply circuit includes a down-converted power supply for down-converting a supplied power supply voltage to any value down to the drive voltage value required for the light emission of the light emitting elements and supplying the down-converted power supply voltage as said drive voltage to the target light emitting elements for the light emitting elements having values of drive voltages required for emitting light smaller than the value of said power supply voltage.
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Accused Products
Abstract
A light emitting element drive apparatus capable of always outputting the lowest voltage satisfying the drive conditions and having a high light emitting efficiency and a low power loss, and a portable apparatus using the same, comprising a LED drive apparatus 10 to which LEDs 20-1 to 20-n of different drive voltages required for emitting light are connected in parallel and driving one or more LEDs, wherein the LED drive apparatus 10 has drive circuits 13-1 to 13-n connected to the corresponding LEDs among a plurality of LEDs and driving the corresponding LEDs with luminances based on set values and power supply circuits 14 and 15 for deciding a drive voltage value required for the highest light emission among one or more LEDs driven to emit light based on drive states of drive circuits (for example terminal voltages of the current source) and supplying a drive voltage having at least the decided value to a plurality of LEDs in parallel.
51 Citations
20 Claims
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1. A light emitting element drive apparatus wherein a plurality of light emitting elements of different drive voltages required for emitting light are connected in parallel and one or more light emitting elements among the plurality of light emitting elements are driven, comprising:
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a plurality of drive circuits connected to corresponding light emitting elements of said plurality of light emitting elements and driving the corresponding light emitting elements with luminances based on set values; a decision circuit for deciding a drive voltage value required for the highest light emission among one or more light emitting elements driven to emit light based on drive states of said plurality of drive circuits; and a power supply circuit for supplying a drive voltage to said plurality of light emitting elements in response to the decision result of said decision circuit, wherein said power supply circuit includes a down-converted power supply for down-converting a supplied power supply voltage to any value down to the drive voltage value required for the light emission of the light emitting elements and supplying the down-converted power supply voltage as said drive voltage to the target light emitting elements for the light emitting elements having values of drive voltages required for emitting light smaller than the value of said power supply voltage.
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2. A portable apparatus having a battery as a power supply voltage source, comprising:
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a plurality of light emitting elements of different drive voltages required for the light emission; at least one illuminated portion illuminated by said light emitting element; and a light emitting element drive apparatus to which said plurality of light emitting elements are connected in parallel and driving one or more light emitting elements among the plurality of light emitting elements, wherein said light emitting element drive apparatus includes; a plurality of drive circuits connected to corresponding light emitting elements of said plurality of light emitting elements and driving the corresponding light emitting elements with luminances based on set values, a decision circuit for deciding a drive voltage value required for the highest light emission among one or more light emitting elements driven to emit light based on drive states of said plurality of drive circuits, and a power supply circuit for supplying a power supply voltage as the drive voltage to said plurality of light emitting elements in response to the decision result of said decision circuit, wherein said power supply circuit supplies a supplied power supply voltage as said drive voltage to said plurality of light emitting elements when the value of said power supply voltage is larger than the voltage value decided by said decision circuit. - View Dependent Claims (3)
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4. A light emitting diode drive device wherein a plurality of light emitting diodes of different drive voltages required for emitting light are connected in parallel and one or more light emitting diodes of the plurality of light emitting diodes are driven, comprising:
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a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values; and a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a drive voltage having a decided value to the plurality of light emitting diodes. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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13. A portable device having a battery as a power supply voltage source, comprising:
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a plurality of light emitting diodes of different drive voltages required for the light emission; at least one illuminated portion illuminated by the light emitting diode; and a light emitting diode drive device to which the plurality of light emitting diodes are connected in parallel and driving one or more light emitting diodes of the plurality of light emitting diodes, wherein the light emitting diode drive device includes; a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values, a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a power supply voltage as a drive voltage having a decided value to the plurality of light emitting diodes, the power supply circuit supplying the supplied power supply voltage as the drive voltage to the plurality of light emitting diodes when a value of the power supply voltage is larger than the decided voltage value. - View Dependent Claims (14, 15)
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16. A portable device having a battery as a power supply voltage source, comprising:
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a plurality of light emitting diodes of different drive voltages required for the light emission; at least one illuminated portion illuminated by the light emitting diode; and a light emitting diode drive device to which the plurality of light emitting diodes are connected in parallel and driving one or more light emitting diodes of the plurality of light emitting diodes, wherein the light emitting diode drive device includes; a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values and a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a power supply voltage as a drive voltage having a decided value to the plurality of light emitting diodes, the power supply circuit fixing the output drive voltage of the power supply circuit to a predetermined set voltage irrespective of the drive states of the light emitting diodes when receiving a predetermined flash operation instruction command.
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17. A portable device having a battery as a power supply voltage source, comprising:
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a plurality of light emitting diodes of different drive voltages required for the light emission; at least one illuminated portion illuminated by the light emitting diode; and a light emitting diode drive device to which the plurality of light emitting diodes are connected in parallel and driving one or more light emitting diodes of the plurality of light emitting diodes, wherein the light emitting diode drive device includes; a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values and a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a power supply voltage as a drive voltage having a decided value to the plurality of light emitting diodes, the power supply circuit down-converting the supplied power supply voltage to any value down to the decided voltage value when the value of the power supply voltage is larger than the decided voltage value and supplying the down-converted power supply voltage as the drive voltage to the plurality of light emitting diodes.
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18. A portable device having a battery as a power supply voltage source, comprising:
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a plurality of light emitting diodes of different drive voltages required for the light emission; at least one illuminated portion illuminated by the light emitting diode; and a light emitting diode drive device to which the plurality of light emitting diodes are connected in parallel and driving one or more light emitting diodes of the plurality of light emitting diodes, wherein the light emitting diode drive device includes; a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values and a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a power supply voltage as a drive voltage having a decided value to the plurality of light emitting diodes, the power supply circuit down-converting the supplied power supply voltage to any value down to the decided voltage value when the value of the power supply voltage is larger than the decided voltage value and supplying the down-converted power supply voltage as the drive voltage to the plurality of light emitting diodes, supplying the supplied power supply voltage as the drive voltage to the plurality of light emitting diodes when the decided voltage value and the value of the power supply voltage are substantially equal, and boosting the supplied power supply voltage to at least the decided voltage value when the value of the power supply voltage is smaller than the decided voltage value and supplying the boosted power supply voltage as the drive voltage to the plurality of light emitting diodes.
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19. A portable device having a battery as a power supply voltage source, comprising:
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a plurality of light emitting diodes of different drive voltages required for the light emission; at least one illuminated portion illuminated by the light emitting diode; and a light emitting diode drive device to which the plurality of light emitting diodes are connected in parallel and driving one or more light emitting diodes of the plurality of light emitting diodes, wherein the light emitting diode drive device includes; a plurality of drive circuits connected to corresponding light emitting diodes of the plurality of light emitting diodes and driving the corresponding light emitting diodes with luminances based on set values and a power supply circuit deciding a drive voltage value required for the highest light emission of one or more light emitting diodes driven to emit light based on drive states of the plurality of drive circuits and supplying at least a power supply voltage as a drive voltage having a decided value to the plurality of light emitting diodes, the power supply circuit including a down-convert power supply down-converting the supplied power supply voltage to any value up to the drive voltage value required for light emission of the light emitting diodes and supplying the down-converted power supply voltage as the drive voltage to the one or more target light emitting diodes for the light emitting diodes having the values of drive voltage required for emitting light smaller than the value of the power supply voltage. - View Dependent Claims (20)
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Specification