JP2006280069A - Electric circuit and digital clock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong the lifetime of a battery in an electric circuit comprising a battery, a control CPU for supplying power from that battery, and a controlled section being operated by the control CPU. <P>SOLUTION: In the electric circuit such as an LED drive circuit 33 comprising a secondary battery 30, a control CPU 60 for supplying power from that secondary battery, and a controlled section 61 being operated through the control CPU by supplying power from the battery, a charge pump 63 is provided in the controlled section and output from the charge pump is fed back to the power supply terminal of the control CPU when the controlled section is operated by the control CPU. In order to preventing the flow from the secondary battery and the flow from the charge pump from being mixed, a means for determining the current flow, e.g. a diode 65, is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention comprises a battery, a control CPU that supplies power from the battery, and a controlled unit that is also supplied with power from the battery and is operated by the control CPU. A light source such as an LED is provided in the controlled unit. The present invention relates to an electric circuit provided with a light emitting function for lighting, a sound function for emitting sound, a motor driving function for driving a vibration motor, a detection function for operating a sensor, a wireless transmission / reception function for wireless transmission / reception, and the like. The present invention also relates to a digital timepiece, particularly a wristwatch, which includes such an electric circuit and digitally displays time.

  Conventionally, a digital wristwatch is driven by a battery power source. When a battery power source continues to pass a current through a heavy load, the voltage value decreases with the passage of time while drawing a discharge curve as shown in FIG. When the voltage value decreases and a voltage value necessary for operating each element cannot be obtained, the battery life is reached.

  By the way, as shown in FIG. 7, the operation limit voltage value V1 necessary for the operation of the control CPU is generally higher than the operation limit voltage value V2 necessary for operating other elements such as some passive elements. . In other words, the control CPU cannot be operated even though the other portions still have sufficient voltage values to operate, resulting in a battery life.

  For this reason, until now, the time for supplying current to the load has been shortened, and the product life has been shortened.

JP-A-8-122468

  However, there are various inconveniences, and there are cases where the power supply voltage fluctuates due to the operation of the LED, etc., and the battery capacity still remains, but the operation voltage falls below the operating voltage of the clock circuit or additional function circuit. It was.

  SUMMARY OF THE INVENTION An object of the present invention is to extend battery life in an electric circuit comprising a battery, a control CPU that supplies power from the battery, and a controlled unit that is operated by the control CPU.

In order to achieve this object, a first aspect of the present invention includes a battery, a control CPU that supplies power from the battery, and a controlled unit that is supplied with power from the battery and is operated by the control CPU. In the electrical circuit
A charge pump is provided in the controlled portion, and when the controlled portion is operated by the control CPU, an output of the charger pump is fed back to a power supply terminal of the control CPU.

  When the controlled portion is operated by the control CPU, the voltage is boosted by the charger pump and the output is fed back to the power supply terminal of the control CPU.

  At this time, it is preferable to provide means for determining a current flow, such as a diode, which prevents mixing of the flow from the battery and the flow from the charger pump. In the controlled part, for example, in addition to the digital display LED, other light emitting functions, a sound function that emits sound, a motor drive function that drives a vibration motor, a detection function that activates a sensor, a wireless transmission / reception function that wirelessly transmits and receives Is provided.

  According to a second aspect of the present invention, there is provided a digital timepiece including the above-described electric circuit in which a digital display LED is provided in a controlled portion.

  According to the first aspect of the present invention, in an electric circuit comprising a battery, a control CPU that supplies electric power from the battery, and a controlled unit that is operated by the control CPU, the control CPU performs the control. When operating the control unit, it is boosted by the charger pump, and its output is fed back to the power supply terminal of the control CPU. Therefore, the battery capacity that has not been used before can be used in advance and the remaining battery capacity is less. It can be used until it reaches the end of its life.

  In addition, when a means for determining the current flow is provided to prevent mixing of the flow from the battery to the control CPU and the flow from the charger pump, the direction of the current is determined and the reverse flow to the battery is prevented. It is possible to make the voltage boosted by the above function effectively only for the control CPU.

  According to the second aspect of the present invention, a digital timepiece having a long battery life can be provided.

The best mode of the present invention will be described below with reference to the drawings.
FIG. 1 shows an analog-driven digital wrist watch that is analog-driven and can digitally display the time by turning on a light source as necessary.

  In the illustrated wristwatch, a windshield glass 11 is fixed to the front side of the watch case 10 and a back cover 12 is screwed to the back side. The back cover 12 is made of a non-magnetic material such as plastic or a metal that is not a ferromagnetic material.

  In the watch case 10, an analog movement 13 is fixed and stored with a resin inner frame 14. The movement 13 is provided with a hand movement shaft 15 for the hour hand, the minute hand, and the second hand concentrically at the center. A disc-shaped circuit board 16 is overlaid on the movement 13. For example, a plurality of thin chip LEDs (digital display LEDs) 17 having a length of 1.6 mm, a width of 0.8 mm, and a thickness of 0.5 mm or less are attached to the circuit board 16.

  Then, as shown in FIG. 2, one number display DIG11, DIG12, DIG13, DIG14 is configured using seven LEDs 17, and the number display DIG11, DIG12, DIG13, DIG14 forming the figure 8 is a plane. Line up four. In the circuit board 16, a central hole a is formed at the center, and a colon 19 is configured by using LEDs 17 provided one by one above and below the central hole a. Then, two numbers DIG11, DIG12, DIG13, and DIG14 are distributed and arranged on the left and right with the colon 19 in between.

  As shown in FIG. 1, the circuit board 16 is attached to the light shielding plate 22 that is slightly thicker than the circuit board 16 and supported by the light shielding plate 22. As shown in FIG. 3, a plurality of light transmission holes 23 are formed in the light shielding plate 22 so as to penetrate the front and back surfaces. The light transmission holes 23 are opened to face the respective thin chip LEDs 17 of the circuit board 16, the LEDs 17 are provided corresponding to the light transmission holes 23, respectively, and the circuit board 16 is provided on the back side of the light shielding plate 22. When attached, the thin chip LED 17 is inserted. And even if the circuit board 16 is overlaid on the light shielding plate 22, the thickness is 1.5 mm or less.

  As shown in FIG. 1, on the light shielding plate 22, a dial plate 24 having a time display such as a time numeral or a time character is superimposed on the surface. The dial 24 is formed, for example, by attaching ink to the surface of a transparent material made of plastic, glass, or the like by printing or using a colored translucent material made of plastic, glass, or the like. Only when the display LED 17 is turned on, a digital display of the LED 17 is formed with a light transmittance that can be seen through the dial 24. Preferably, the light transmittance is 30 to 70%. Then, the entire periphery of the dial 24 is placed in the watch case 10 with the peripheral edge of the dial 24 being applied to the parting portion of the watch case 10.

  In this way, the light shielding plate 22 is provided on the back side of the dial plate 24, the circuit board 16 is disposed on the back side of the light shielding plate 22, and the movement 13 is provided on the back side of the circuit board 16. Thereby, the LED 17 for digital display on the circuit board 16 is arranged on the back side of the dial plate 24.

  The hand movement shaft 15 penetrates from the center hole a of the circuit board 16 to the center hole of the dial plate 24 (indicated by reference numeral c in FIG. 1) through the central hole of the light shielding plate 22 (indicated by reference numeral b in FIG. 3). The front end is exposed to the front side of the dial plate 24. Then, the hour hand 25, the minute hand 26, and the second hand 27 are attached to the tip.

  A charging circuit is provided on the back cover 12 side of such a movement 13, and a coin-type secondary battery 30 is arranged so as to overlap the movement 13, and the coil bobbin 31 is annularly surrounded so as to surround the secondary battery 30. And the secondary coil 32 is attached. That is, in the illustrated example, the secondary battery 30 and the secondary coil 32 are arranged on the same plane in the watch case 10.

  In the wristwatch case 10, an LED drive circuit 33 that drives the LEDs 17 is attached to the back side of the circuit board 16 in the same plane as the movement 13.

  On the other hand, in the illustrated wristwatch, a winding stem 36 for attaching the crown 35 to the outer end is inserted through the wristwatch case 10 and placed in the movement 13. Although not shown, an operation shaft for attaching a switch to the outer end is similarly inserted through the watch case 10 and placed in the movement 13.

  In the illustrated digital wristwatch, normally, the digital display LED 17 is not lit, the movement 13 is driven by the secondary battery 30 to rotate the hands 25 to 27, and the time display on the dial 24 is indicated. Analog display. For example, in a dark place, if necessary, the LED 17 is turned on by an appropriate external operation, and the light of the LED 17 is guided through the light transmission hole 23 of the light shielding plate 22 to pass through the dial plate 24. Etc. are digitally displayed.

FIG. 4 shows a block diagram of the LED drive circuit 33 of the wristwatch described above.
Reference numeral 30 in the figure denotes the secondary battery described above. Reference numeral 60 denotes a control CPU that supplies power from the secondary battery 30. Reference numeral 61 denotes a controlled unit that is supplied with electric power from the secondary battery 30 and is turned on / off by the control CPU 60. The controlled unit 61 has a digital display unit 62 and a charger pump 63. The digital display unit 62 is composed of a number display DIG 11, DIG 12, DIG 13, DIG 14, and colon 19, each of which includes the thin chip LED (digital display LED) 17.

  The charger pump 63 is, for example, an element having the ability to change the input of 1V, 3A to the output of 3V, 1A, and converts the current supplied from the secondary battery 30 into a predetermined voltage and outputs it. The number of V output is a value specific to the element, and the designer selects an appropriate one according to the application. When the controlled portion 61 is turned on by the control CPU 60, the charger pump 63 is also turned on simultaneously. When the controlled portion 61 is turned on, the voltage is boosted by the charger pump 63 and the output is fed back to the power supply terminal of the control CPU 60.

  Reference numeral 64 in FIG. 4 denotes an input unit that activates the LED drive circuit 33. Specifically, the input unit 64 is configured by a switch that operates when the digital display unit 62 is turned on to operate the operation shaft described above. When the switch operation is released, that is, when the input unit 64 is turned off, the control CPU 60 turns it off to end the operation of the controlled unit 61, turns it off, and returns to the standby state.

  Reference numeral 65 in FIG. 4 denotes a diode which is a means for determining a current flow. The diode 65 determines the direction of current and mixes the flow of supplying power from the secondary battery 30 to the power supply terminal of the control CPU 60 and the flow of returning the output of the charger pump 63 to the power supply terminal of the control CPU 60. prevent. Thereby, the backflow to the secondary battery 30 is prevented by the diode 65 so that the voltage boosted by the charger pump 63 works effectively only for the control CPU 60. Further, when the digital display unit 62 operates, the control CPU 60 is prevented from being stepped down, and the clock circuit and the additional function circuit are prevented from being inactivated.

  In this way, as shown in FIG. 4, the secondary battery 30, the control CPU 60 that supplies power from the secondary battery 30, and the controlled unit 61 that is operated by the control CPU 60 are included. In the LED driving circuit 33, when the controlled CPU 61 operates the controlled portion 61, the charger pump 63 boosts the voltage and feeds back the output to the power supply terminal of the control CPU 60. Therefore, the conventional shaded portion s in FIG. Use the battery capacity that was not used upfront, and change the discharge curve of the secondary battery 30 from p to q as shown in FIG. 6 until the remaining capacity of the secondary battery 30 decreases. The battery life can be extended from f to g.

  In the above-described example, the case where the present invention is applied to the LED drive circuit 33 of the digital wristwatch has been described. However, the present invention is not limited to the LED drive circuit 33, and the battery-driven electric circuit has a large voltage difference between operation and stop. And a product including the same. For example, in addition to switch input, wireless input via an antenna, voice input using a microphone, timer signal input using a timer, etc. The present invention can be applied to an electric circuit provided with an audio function, a motor driving function for driving a vibration motor, a detection function for operating a sensor, a wireless transmission / reception function for wireless transmission / reception, and a product including the electric circuit.

1 is a schematic longitudinal sectional view of an analog-led digital wrist watch according to the present invention capable of performing digital display. It is a top view of the circuit board used with the wristwatch. It is a top view of the light-shielding plate used with the wristwatch. It is a block diagram of the LED drive circuit of the wristwatch. It is a graph which shows the battery discharge curve explaining the forward use of battery capacity. It is a graph which shows the battery discharge curve of the said wristwatch. It is a graph which shows the battery discharge curve of the conventional wristwatch.

Explanation of symbols

17 Digital display LED
30 Secondary battery 33 LED drive circuit (electric circuit)
60 CPU for control
61 Controlled Unit 62 Digital Display Unit 63 Charger Pump 64 Input Unit 65 Diode (Means to Determine Current Flow)

Claims (4)

In an electric circuit comprising a battery, a control CPU that supplies power from the battery, and a controlled unit that is supplied with power from the battery and is operated by the control CPU,
An electric circuit comprising: a charge pump provided in the controlled portion; and when the controlled portion is operated by the control CPU, an output of the charger pump is fed back to a power supply terminal of the control CPU.   The electrical circuit of claim 1, comprising means for determining a current flow that prevents mixing of the flow from the battery and the flow from the charger pump.   The electric circuit according to claim 1, wherein a digital display LED is provided in the controlled portion.   A digital timepiece comprising the electric circuit according to claim 3.

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