Power supply circuit device and electronic apparatus provided therewith

A technology of power supply circuit and current detection circuit, applied in emergency protection circuit devices, output power conversion devices, circuits, etc., can solve the problems of high electric power and affect the service life of batteries, etc., to achieve stable brightness, prolong service life, reduce The effect of electrical power consumption

Inactive Publication Date: 2007-11-21
SHARP KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the higher the reference potential Vref, the greater the electrical power lost in resistor R1
This affects the service life of a battery used as a DC power supply 1 in a power supply circuit device used in a portable electronic device or the like

Method used

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  • Power supply circuit device and electronic apparatus provided therewith
  • Power supply circuit device and electronic apparatus provided therewith
  • Power supply circuit device and electronic apparatus provided therewith

Examples

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Comparison scheme
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no. 1 example

[0035] A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the internal configuration of the power supply circuit device of the present embodiment. In FIG. 1 , circuit blocks that are used for the same purpose as those in the conventional power supply circuit device shown in FIG. 12 are denoted by the same reference numerals, and their detailed description will not be repeated.

[0036] As in the case of the power circuit device shown in FIG. 12, the power circuit device shown in FIG. 1 includes a DC (direct current) power source 1, an input capacitor 2, a coil 3, a diode 4, an output capacitor 5, and a resistor R1 , and provide the boosted output voltage to the load 7. The power circuit arrangement shown in FIG. 1 also comprises a control circuit arrangement 6 for switching between storing energy into the coil 3 and releasing energy from the coil 3 . Similar to the control circuit device 60 of the p...

no. 2 example

[0061] A second embodiment of the present invention will be described with reference to the drawings. As in the case of the power supply circuit device of the first embodiment, the power supply circuit device of the present embodiment is configured as shown in the block diagram of FIG. 1 . In the following description, only the differences from the power supply circuit device of the first embodiment are explained, and explanations for those circuit blocks that can also be found in the first embodiment will no longer be as in the first embodiment Repeat as in.

[0062] Unlike the power supply circuit device of the first embodiment, the power supply circuit device of the present embodiment makes the output current to the load 7 smaller than that in normal operation when low-power operation is performed. That is, it is assumed that the output current flowing through the load 7 in normal operation is Io, and the output current flowing through the load 7 in low power operation is ...

no. 3 example

[0068] A third embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram showing the internal configuration of the power supply circuit device of the present embodiment. In FIG. 4 , those circuit blocks that are used for the same purpose as in the power supply circuit device shown in FIG. 1 are identified with the same reference numerals, and their detailed description will not be repeated.

[0069] Unlike the power circuit device of the first embodiment (see FIG. 1 ), the power circuit device of this embodiment has a configuration in which switching between normal operation and low power operation is performed based on a control signal fed from the outside. Therefore, as shown in FIG. 4 , the control circuit device 6 a has a control signal input terminal CONT to which a control signal from the outside is fed. In addition, the control circuit 62a provided in the control circuit device 6a includes an external signal detecti...

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PUM

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Abstract

There are provided a resistor R 2 arranged in parallel with a resistor R 1 that produces a feedback signal indicating a value of an output current to a load 7 and, in a control circuit device 6 , a voltage changing circuit 68 that changes a reference potential applied to the inverting input terminal of an error amplifier 64 . Thus, when the electric power of a DC power source 1 decreases, by changing the reference potential applied to the error amplifier 64 and the resistance of a resistor that detects the value of the output current to the load 7 , it is possible to reduce the electric power consumption of the resistor and thereby prolong a lifespan of the DC power source.

Description

technical field [0001] The present invention relates to a power supply circuit device for stepping up or stepping down (set up or set down) an input voltage supplied from a direct current (DC) power supply to supply the input voltage to a load, and to an electronic device provided with such a power supply circuit device. Background technique [0002] In recent years, light-emitting diodes (white LEDs), which are excellent in durability, luminous efficiency, and space saving, have been incorporated in portable electronic devices such as cellular phones, PDAs (Personal Digital Assistants), and digital cameras. One of the lighting sources (backlight or foreground light) of the liquid crystal display device (LCD) in the LCD is used. The brightness of a white LED increases with the amount of current passing through it. However, white LEDs require a relatively high forward voltage of about 4V, and the forward voltage of these white LEDs varies greatly. [0003] A plurality of wh...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/28H02M1/08H02H7/12H01L33/00H02M3/155
CPCH02M2001/0009H02M3/156H02M1/0009
Inventor 铃木友广
Owner SHARP KK
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