JP2011114911A - Charge control device and electronic timepiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further promptly operate a control part even if a voltage of a secondary-side power supply lowers due to a charge current at non-contact charging. <P>SOLUTION: This charge control device includes a secondary power supply 1 which generates power by electromagnetic induction action according to a magnetic field which is generated by a primary power supply, a secondary battery 7-1 charged by the generated power, a capacitor 4-2 which is charged by the generated power and is shorter in time than the secondary battery 7-1 until it is charged to a preset predetermined value, and a control part 6 which is operated when a voltage of the capacitor 4-2 exceeds the predetermined value, and controls charging the secondary battery 7-1 by opening and closing a power feed passage to the secondary battery 7-1 from the secondary power supply 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charging control device that controls charging of a secondary battery or the like mounted on a portable device such as a wristwatch.

  Due to the electromagnetic induction action between the two coils (primary coil, secondary coil), non-contact power is supplied from the power transmission side to the power reception side and the power storage unit such as a secondary battery or an electric double layer capacitor is charged. Contact charging is known. Non-contact charging using a coil has advantages over contact-type charging in terms of product airtightness and reduced contact failure. On the other hand, the charging efficiency and stability are inferior to the contact type.

  For example, in non-contact charging, a secondary coil is used as a power source. However, since the DC resistance of the secondary coil becomes the internal resistance of the power supply, a drop in the power supply voltage is unavoidable when a large current is passed. As a countermeasure for such a situation, Patent Document 1 discloses a technique for preventing a drop in the power supply voltage on the secondary side and making the voltage or current constant by increasing the power transmission capability on the primary side according to the load fluctuation on the secondary side. Has been proposed. Patent Document 2 proposes a technique for charging by controlling a power feeding path by a control unit.

  These technologies assume a product such as a mobile phone in which the casing is made of plastic or the like and the capacity of the secondary battery or electric double layer capacitor used for the standby current of the product is sufficient. Since the casing is made of plastic or the like, it is difficult to generate heat due to the linkage of magnetic flux. In addition, since the secondary battery has sufficient capacity, the battery voltage is unlikely to become extremely low even if left for a long time.

  On the other hand, the above technique is not suitable for products such as watches. One reason for this is that the watch case is made of metal. In the first place, when a metal is inserted between the primary coil and the secondary coil, the power transmission efficiency of power is significantly reduced. Also, if you try to forcibly supplement the power required to prevent the voltage drop that occurs on the secondary side by increasing the output on the primary side, most of the power is replaced with heat at the metal part of the housing, so heat is generated. This is very dangerous.

  Another reason is that a battery having a sufficiently large capacity cannot be mounted due to space limitations. Since the capacity of the battery is not sufficient, for example, even if it is configured to disconnect the discharge circuit below a certain voltage using a dedicated battery protection IC, the power consumption of the dedicated IC itself, leakage of circuit disconnecting means, When the battery is left for a long time due to self-discharge of the battery itself, the battery voltage may become extremely low. It is quite possible that the battery voltage has decreased so that at least the control unit (control circuit) that controls the operation of the wristwatch cannot be operated. For example, a case where a device that has been stored for a long time in a desk and has stopped functioning is charged with a wristwatch.

JP 2008-236880 A JP 2009-027781 A

  However, as described above, since there is a danger of heat generation of the metal casing, it is difficult to increase the output on the primary side in order to ensure the voltage on the secondary side. Therefore, in a wristwatch employing non-contact charging, a drop in power supply voltage due to the internal resistance of the secondary power supply cannot be avoided. For this reason, when charging a secondary battery or the like that has been left unattended for a long time and has a battery voltage that has dropped below the operating voltage of the control circuit, the voltage generated by the secondary power supply and the battery voltage are almost equal. The voltage can drop to some extent.

  In such a charged state, since the voltage is lower than the operating voltage of the control circuit, the secondary device does not start at the moment when it is put on the charger. Therefore, until the charging proceeds and the voltage generated at the secondary power supply exceeds the lower limit value of the operating voltage of the secondary circuit, even the charging display for notifying the user that charging is in progress does not function. For this reason, the user may misunderstand that the device has failed. In addition, there is a method of providing an LED (Light Emitting Diode) in the power supply path as a countermeasure for such a state. However, not only the efficiency of charging is lowered, but also the display switching performance cannot be controlled such as switching the display according to the charging process. Is limited.

  The present invention has been made in view of the above, and is a charge control capable of operating a control unit more quickly even when a voltage drop of a secondary power supply occurs due to a charging current of non-contact charging. An object is to provide a device and an electronic timepiece.

  In order to solve the above-described problems and achieve the object, the present invention provides a secondary power supply unit that generates power by electromagnetic induction according to a magnetic field generated by the primary power supply unit, and the generated power. A first power storage unit to be charged, a second power storage unit that is charged with the generated power and charged to a predetermined specified value, and is smaller than the first power storage unit, and a voltage of the second power storage unit And a controller that controls charging of the first power storage unit by opening and closing a first power supply path from the secondary power supply unit to the first power storage unit. It is characterized by.

  According to the present invention, there is an effect that the control unit can be operated more rapidly even when the voltage drop of the secondary power supply occurs due to the charging current of non-contact charging.

FIG. 1 is a schematic diagram showing a schematic configuration of a charging system according to the present embodiment. FIG. 2 is a block diagram illustrating an example of the configuration of the electronic timepiece according to the present embodiment. FIG. 3 is a circuit diagram showing an example of the circuit configuration of the electronic timepiece according to the present embodiment. FIG. 4 is a flowchart showing the overall flow of the charging control process in the present embodiment. FIG. 5 is a diagram illustrating the electronic timepiece in the switching charge state. FIG. 6 is a diagram illustrating the electronic timepiece in the switching charge state. FIG. 7 is a diagram illustrating the electronic timepiece in the switching charge state. FIG. 8 is a diagram illustrating the electronic timepiece in the switching charge end state. FIG. 9 is a diagram illustrating a change in voltage at a predetermined location during the switching charge control. FIG. 10 is a diagram showing the locations at which the voltages shown in FIG. 9 are measured. FIG. 11 is a diagram illustrating transition of various voltages when charged from an overdischarged state.

  Exemplary embodiments of a charge control device and an electronic timepiece according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following, an embodiment in which the charge control device is applied to a rechargeable wristwatch (electronic timepiece) will be exemplified, but the present invention can be applied to any device as long as the device operates with a battery or the like charged by a non-contact charging method.

  First, a configuration example of a charging system including an electronic timepiece and a charger for charging the electronic timepiece will be described with reference to FIG. FIG. 1 is a schematic diagram showing a schematic configuration of a charging system according to the present embodiment. This charging system includes a charger 200 and a rechargeable electronic timepiece 100. The charger 200 includes a power transmission module 211 that functions as a primary power supply unit, a power plug 212, an oscillation circuit 215, and a power supply circuit 216. The electronic timepiece 100 includes a secondary power supply unit 1 as a power receiving module, a control unit 6, and a secondary battery 7-1.

  The charging system attaches the power plug 212 to a household AC 100V outlet (not shown), and sets the electronic timepiece 100 at a predetermined mounting position of the charger 200, thereby transferring the power from the power transmission module 211 to the secondary power supply unit 1. Power is supplied by contactless power supply. Thereby, the secondary battery 7-1 inside the electronic timepiece 100 is charged.

  The power transmission module 211 of the charger 200 includes, for example, a cylindrical magnetic core 213 made of a mixed material of manganese and zinc, and a primary coil 214 wound around the magnetic core 213. Yes. Both ends of the primary coil 214 are connected to the oscillation circuit 215. The oscillation circuit 215 is connected to a power supply circuit 216 that converts household AC 100 V into a desired voltage. The oscillation circuit 215 causes an alternating current to flow through the primary coil 214 when the power plug 212 is attached to a household AC 100V outlet. When an alternating current is passed through the primary coil 214, the primary coil 214 generates an alternating magnetic field in a direction along the winding center axis in accordance with the alternating current. At this time, since the magnetic core 213 is disposed at the winding center of the primary coil 214, the magnetic flux that goes around the outer periphery of the coil and short-circuits is reduced, and the alternating magnetic field generated from the primary coil 214 is an electronic timepiece. Propagates efficiently to the 100 side.

  On the other hand, the secondary power supply unit 1 built in the electronic timepiece 100 includes a secondary coil 1a and a magnetic core 1b. The secondary coil 1a is provided so as to face the primary coil 214 of the charger 200 via a predetermined gap when the electronic timepiece 100 is set at a predetermined mounting position of the charger 200. The magnetic core 1b is disposed on a surface opposite to the surface facing the primary coil 214 of the secondary coil 1a. The magnetic core 1b is made of a mixed material of manganese and zinc.

  Specifically, the secondary coil 1a is configured as a circular spiral coil, for example. Moreover, the magnetic body core 1b is comprised as an annular core arrange | positioned concentrically with the secondary coil 1a, for example. The secondary coil 1a and the magnetic core 1b are integrally supported by a bobbin (not shown in FIG. 1).

  When the electronic timepiece 100 is set at a predetermined mounting position of the charger 200 and an alternating magnetic field is generated from the primary coil 214, the magnetic flux of the alternating magnetic field from the primary coil 214 is applied to the secondary coil 1a by electromagnetic induction. An alternating current is induced in the direction of cancellation. In addition, the magnetic body core 1b is arrange | positioned on the surface on the opposite side to the opposing surface with respect to the primary coil 214 of the secondary coil 1a. For this reason, the magnetic flux of the alternating magnetic field generated from the primary coil 214 is attracted by the magnetic core 1b, and the leakage magnetic flux is reduced. Thereby, the alternating magnetic field generated from the primary coil 214 is efficiently converted into the alternating current of the secondary coil 1a. Both ends of the secondary coil 1 a are connected to the control unit 6, and an alternating current flowing through the secondary coil 1 a is supplied to the control unit 6. Details of the function of the control unit 6 will be described later.

  Note that the configuration in FIG. 1 is an example, and any configuration that has been used in the past can be used as long as it can be charged by supplying power in a non-contact manner by electromagnetic induction between the primary coil and the secondary coil. Applicable.

  Next, an outline of the configuration of the electronic timepiece 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of the configuration of the electronic timepiece 100 according to the present embodiment. As shown in FIG. 2, the electronic timepiece 100 includes, in addition to the above-described secondary power supply unit 1, control unit 6, and secondary battery 7-1, main components are a backflow prevention element 4-1 and a capacitor 4-2. And a switching unit 7-2, a load unit 8-1, and a switching unit 8-2.

  The secondary power supply unit 1 generates electric power by electromagnetic induction according to the magnetic field generated by the power transmission module 211 as described above. The control unit 6 controls the charging of the secondary battery 7-1 and the operation of the load unit 8-1. The secondary battery 7-1 is a power storage unit (first power storage unit) that is charged according to control by the control unit 6 with generated electric power. The first power storage unit may be configured by an electric double layer capacitor.

  The backflow prevention element 4-1 is an element that prevents the electric charge stored in the capacitor 4-2 from flowing into the secondary battery 7-1. The backflow prevention element 4-1 is preferably a Schottky diode with a small voltage drop because of the ease of selecting other components. At the time of selection, one having a small leakage current and little influence of temperature change is more preferable, but an appropriate one is selected from the characteristics, cost, size and the like.

  The capacitor 4-2 is a power storage unit (second power storage unit) that is connected to the secondary power supply unit 1 and is charged by electric power generated in the secondary power supply unit 1. As described above, in the present embodiment, in addition to the secondary battery 7-1, the capacitor 4-2 that is a power storage element having a shorter charging time than the secondary battery 7-1 is provided. The voltage of the capacitor 4-2 increases instantaneously when charging is started. Since the current that flows to charge the capacitor 4-2 is very small, a large voltage drop of the secondary power supply unit 1 that occurs when the secondary battery 7-1 is charged does not occur. In the present embodiment, the control unit 6 is operated by the voltage of the power storage unit (capacitor 4-2) that is instantaneously charged in this way. Thereby, even if it is a case where the voltage drop of the secondary power supply part 1 arises with the charging current of non-contact charge, the control part 6 can be operated more rapidly. It should be noted that the second power storage unit is charged at least from the first power storage unit (secondary battery 7-1) for a charging time to be charged to a predetermined specified value such as a lower limit value of the operating voltage at which the control unit 6 operates. Small is enough. As described above, since the battery can be charged up to the operating voltage instantaneously, it is desirable to use the capacitor 4-2 as the second power storage unit.

  The switching unit 7-2 is a means for opening and closing a power supply path (first power supply path) from the secondary power supply unit 1 to the secondary battery 7-1.

  The load unit 8-1 operates with electric power generated by the secondary power supply unit 1. The load unit 8-1 may be anything that can be operated only by the electric power of the secondary power supply unit 1. Moreover, considering the voltage drop of the secondary power supply unit 1, it is preferable to use a light load that can sufficiently operate with a current of less than 10 mA, for example. The load unit 8-1 can be configured by, for example, a display unit such as an LED that displays the state of charge, and the minimum necessary sensors for user operations. In addition, as the load unit 8-1, a hand moving unit for moving a hand for displaying time, a frequency detecting unit for detecting the frequency of AC power generated in the secondary power supply unit 1, and resonance of the secondary power supply unit 1. A frequency adjustment unit for electrically adjusting the frequency, a position detection unit for detecting a positional deviation between the primary coil 214 and the secondary coil 1a, a charger 200 (power transmission module 211), and the electronic timepiece 100 ( A communication unit that communicates information with the secondary power supply unit 1) by non-contact communication or the like can be applied. In FIG. 2, only one load unit is displayed, but the load unit is not limited to one.

  The switching unit 8-2 is a means for opening and closing a power supply path (second power supply path) from the secondary power supply unit 1 to the load unit 8-1.

  As will be described later, the control unit 6 controls the opening and closing of the switching unit 7-2 and the switching unit 8-2 according to the voltage of the capacitor 4-2, the voltage of the secondary battery 7-1, and the like, thereby operating voltage. , The charging of the secondary battery 7-1 and the operation of the load unit 8-1 are controlled. Hereinafter, the process of controlling charging while switching the switching unit 7-2 and the switching unit 8-2 in this way is referred to as switching charge control.

  Next, a circuit configuration example for realizing the function shown in FIG. 2 will be described with reference to FIG. FIG. 3 is a circuit diagram illustrating an example of a circuit configuration of the electronic timepiece 100 according to the present embodiment. As shown in FIG. 3, the electronic timepiece 100 includes a secondary power supply unit 1, a rectifying / smoothing unit 2, a constant voltage unit 3, a backflow prevention element 4-1, a capacitor 4-2, and a reset unit 5. The control unit 6, the secondary battery 7-1, the switching unit 7-2, the load unit 8-1, the switching unit 8-2, the battery voltage detection unit 9, the charge detection unit 10, and the battery protection Part 11.

  The secondary power supply unit 1 includes the secondary coil 1a that performs non-contact charging as described above. The rectification / smoothing unit 2 rectifies and smoothes the electric power generated in the secondary coil 1a. The constant voltage unit 3 converts the smoothed voltage to a constant voltage (for example, 4.5 V). The constant voltage unit 3 is preferably composed of, for example, a regulator IC or a Zener diode.

  The backflow prevention element 4-1 is configured by a Schottky diode or the like as described above. The capacitor 4-2 is a power storage unit (second power storage unit) that is charged by the power generated in the secondary power supply unit 1 as described above.

Here, if the Schottky diode and the control unit 6 are approximately regarded as resistors, the CR curve with the capacitor 4-2 can be simply calculated. For example, assuming that the equivalent resistance for the forward current of the Schottky diode is R1, the equivalent resistance for the reverse current is R2, the equivalent resistance of the control unit 6 is R3, and the capacitance of the capacitor is C, the CR during charging and discharging The time constant of the curve is expressed by the following equations (1) and (2), respectively.
τ = (R1 + R3) / R1 * R3 * C (1)
τ = (R1 + R2) / R1 * R2 * C (2)

  Both are of the same form, but since R1> R2, charging is performed faster than discharging. For this reason, the charging time for the capacitor 4-2 can be made shorter than the feeding time for the secondary battery 7-1 or the load unit 8-1.

  The reset unit 5 resets the operation of the control unit 6. The reset unit 5 is preferably composed of a complementary output voltage detection IC. When the voltage of the capacitor 4-2 becomes equal to or lower than the control unit reset voltage (for example, 2.4 V) that is a predetermined threshold value (third threshold value), the reset unit 5 configured by such a voltage detection IC immediately Lower the subsequent voltage to L level. The ON / OFF and OFF → ON capabilities of the voltage detection IC should be selected to have a capability sufficient to satisfy the power-on reset conditions for the components selected by the CPU 6-4 of the control unit 6. In addition, it is preferable not to place a large-capacitance capacitor that hinders this ability after the reset unit 5.

  When the voltage of the capacitor 4-2 falls below the control unit reset voltage, the reset unit 5 immediately drops the voltage of the subsequent components to the L level, and the voltage of the capacitor 4-2 changes to a predetermined reset release voltage (= control). In the case where the voltage exceeds the reset voltage (hysteresis width + hysteresis width), the voltage of the subsequent components is immediately set to the H level.

  The control unit 6 includes a voltage regulator IC 6-1, external capacitors 6-2 and 6-3, a CPU 6-4, and resistors 6-5 to 6-7.

  The voltage regulator IC 6-1 generates a constant voltage (for example, 1.6 V). The voltage regulator IC 6-1 may be selected according to the operating voltage of the CPU 6-4. As the external capacitors 6-2 and 6-3, a large-capacity capacitor that hinders the ability of the reset unit 5 as described above is avoided.

  When the voltage becomes L level by the reset unit 5, the output signal of the CPU 6-4 becomes L. Therefore, basically, all the output signals of the CPU 6-4 are set to be active H. This is because when the active state is set to “L”, the function is always turned on during the reset state, and control becomes impossible. However, there is no problem with the configuration based on that expectation.

  Further, since the voltage is regulated by the voltage regulator IC 6-1, the input signal needs to be converted. For ease of configuration, these inputs are preferably an H input in a normal state by a pull-up resistor, and an L input when there is a signal. However, when this signal is input, the current flowing through the pull-up resistor is also an element that consumes the charge of the capacitor 4-2. For this reason, it is preferable to set the pull-up resistor to a higher resistance value as long as conditions permit. However, since an adverse effect may occur if the value is larger than necessary, it should be set within an allowable range. In addition, since the current consumption varies depending on the processing speed, the CPU 6-4 preferably forms a program so that the processing can be performed at a low speed.

  As shown in FIG. 3, the secondary battery 7-1 can be constituted by, for example, a lithium ion battery. In FIG. 3, an Nch MOSFET is disposed as the switching unit 7-2. The switching unit 7-2 may be configured with a transistor. However, in the case of a transistor, since the base current component is a consumption element of the capacitor 4-2, it is preferable to use a MOSFET. The MOSFET (switching unit 7-2) also functions as a charge control MOSFET of the battery protection unit 11 (described later).

  The load unit 8-1 operates with the electric power generated by the secondary power supply unit 1 as described above. The switching unit 8-2 functions as means for switching a power feeding path (second power feeding path) from the secondary power supply unit 1 to the load unit 8-1 during the switching charge control. The switching unit 8-2 functions as a drive circuit for controlling the load unit 8-1.

  The battery voltage detector 9 detects the voltage (battery voltage) of the secondary battery 7-1. The battery voltage detector 9 is preferably composed of an external A / D (analog / digital) element or a voltage detection IC. In particular, the battery voltage detector 9 is preferably composed of a voltage detection IC because it is inexpensive and consumes little current.

  The battery voltage detection unit 9 detects whether or not a detection value defined as a voltage (switching charge release voltage) that becomes a threshold value (second threshold value) for canceling the switching charge control is reached. However, an actual product may need to have a plurality of detection values for other purposes. If the battery voltage detection unit 9 is configured by only the voltage detection IC, only one voltage (detection value) that can be detected can be set. For this reason, a device such as increasing the voltage that can be detected by providing a plurality of voltage dividing resistors having different voltage dividing ratios is required. Further, since the voltage is different from that of the CPU 6-4, the output of the battery voltage detection unit 9 must be composed of an Nch open drain.

  Note that the battery voltage detector 9 requires attention to the following two points.

  The first caution is that the battery voltage detector 9 may not function when the battery voltage is extremely low. For example, when the battery voltage detection unit 9 is configured by a voltage detection IC, the voltage detection IC cannot operate up to about 1.0 V, and the output becomes unstable. This problem can be solved, for example, if the CPU 6-4 includes an A / D terminal. However, if the CPU 6-4 having an A / D terminal is indispensable, convenience is impaired due to restriction of component selection. Therefore, in the present embodiment, this problem is solved as follows.

  Here, the details of this problem will be further described. First, when charged from a level that is lower than the operating voltage of the voltage detection IC, the controller 6 is started after charging the capacitor 4-2. The program of the CPU 6-4 of the control unit 6 starts from the initial state. If charging is detected at this time, the charging can be uniquely interpreted as charging from an overdischarged state, so the control unit 6 immediately starts switching charge control. On the other hand, the control unit 6 performs charging while confirming the battery voltage. When the battery voltage reaches the switching charge release voltage, the control unit 6 immediately ends the switching charging control and connects the power supply path to the secondary battery 7-1. It is desirable to fix to. However, the control unit 6 cannot determine whether the battery is activated from a state where the battery voltage is less than 1.0 V or from a state where the battery voltage is slightly lower than the switching charge release voltage. Therefore, for example, in order to immediately stop the switching charge control when the battery voltage is started from the latter state and the battery voltage reaches the switching charge release voltage in a short time, the control unit 6 detects the battery voltage immediately after starting. There is a need to.

  On the other hand, as described above, the battery voltage detector 9 may not function in a state where the battery voltage is extremely low (the former state). Thus, it is not preferable to detect the battery voltage at the time when there is a risk of not functioning normally. When the switching charge control is canceled due to erroneous detection, the reset of the control unit 6 by the reset unit 5 works, and the switching charging control and reset are repeated, resulting in poor efficiency. In addition, if the processing for causing the load unit 8-1 to function is not included at least once from the start of the program until the voltage is detected, the battery is charged without being controlled as a result. is there.

  Therefore, as a workaround for this problem, in this embodiment, when switching charge control is performed from the initial state, at least the time until the battery voltage detection unit 9 reaches a voltage at which the battery voltage detection unit 9 can operate (detection impossible time) is the battery. Even if a voltage is not detected or a battery voltage is detected, the detection result is not reflected in the control.

  For example, when the battery voltage detection unit 9 is configured by a voltage detection IC, it is only necessary to secure a time for charging the voltage detection IC to a voltage (for example, 1.0 V) at which the voltage detection IC can operate normally. For example, an appropriate non-detectable time corresponding to the charging capability of the secondary power supply unit 1 is given in advance to the CPU 6-4, and the CPU 6-4 may be configured to detect the battery voltage after the non-detectable time has elapsed. .

  In the configuration of FIG. 3, since the discharge control MOSFET 11-2 (details will be described later) is closed, there is a voltage drop due to a parasitic diode. For this reason, the voltage applied to the battery voltage detector 9 apparently becomes higher than the battery voltage by the voltage drop of the parasitic diode. For example, if the value of the voltage drop is about 0.6V, the battery voltage detector 9 can function if the battery voltage is actually charged to 0.4V.

  Thereby, the control part 6 can control without a risk, even if it is any starting from the state from which a battery voltage is less than 1.0V, and starting from the state slightly less than a switching charge release voltage. .

  Even if the limitation of detection within the non-detectable time cannot be achieved for some reason and the switching charge control is canceled due to an erroneous determination, the reset unit 5 resets the control unit 6 so that the switching charge control is performed again. Will not cause any problems.

  When a lithium ion battery is used as the secondary battery 7-1, recharging from around 0 V may be prohibited. In such a case, a means for prohibiting recharging from around 0V may be provided. In many cases, a protection IC corresponding to a lithium ion battery has a specification that prohibits charging from 0 V, and therefore, the battery protection unit 11 may be configured to include the protection IC. When the operable voltage of the battery voltage detector 9 is high, or when the secondary battery 7-1 can be charged from 0V, the above-described control is required.

  The second caution is that an error is included in the detection result of the battery voltage due to the voltage drop of the discharge control MOSFET 11-2. As described above, while the discharge control MOSFET 11-2 is closed, the charging current flows through the parasitic diode of the discharge control MOSFET 11-2. For this reason, the voltage of the circuit seems to be higher than the actual battery voltage by the voltage drop due to the parasitic diode.

  Therefore, in order to prevent malfunction due to this, it is necessary to set the switching charge release voltage to a higher value by an appropriate value than the overdischarge release voltage of the protection IC 11-1 (details will be described later). For example, when the protection IC 11-1 having an overdischarge release voltage of 2.7V is used, the switching charge release voltage is set to 3.5V including the voltage drop of the parasitic diode and the influence of ripple caused by charging.

  The charge detection unit 10 detects the presence / absence of charge (start and end of charge) depending on whether or not power is supplied from the secondary power supply unit 1. The charge detection unit 10 includes a voltage conversion MOSFET 10-1, a detection resistor 10-2, and a backflow prevention diode 10-3.

  Note that the control unit 6 may be configured to start the switching charge control immediately without detecting the charger 200 when it is placed on the charger 200 and started. The reason why the control unit 6 is activated from the OFF state is that it is not connected to the charger 200 and does not need to be detected. However, in consideration of convenience in the inspection process and the like, it is preferable to detect the presence or absence of the charger 200 at startup. If the switching charge control is forcibly executed after the control unit 6 is activated, various operation modes may not be tested in the inspection process. For this reason, the control unit 6 is configured to detect charging at the time of start-up, shift to switching charge control if charging is detected, and determine that process inspection is being performed if charging is not detected.

  In order to configure in this way, the charge detection signal needs to be output before the control unit 6 goes to read the rising input signal. In addition, it is necessary to avoid a state in which the charge detection unit 10 cannot detect that it is charged even though it is actually charged.

  For this reason, it is preferable to increase the detection sensitivity by setting the value of the resistor 10-2 of the charge detection unit 10 higher, and to quickly send a signal to the CPU 6-4 by the MOSFET 10-1. However, if the value of the resistor 10-2 is excessive, there is a possibility of causing malfunction due to noise or exceeding the input rating of the MOSFET 10-1 depending on the charging current. For this reason, it is necessary to set the value of the resistor 10-2 in consideration of actual conditions.

  The battery protection unit 11 is a circuit that protects the secondary battery 7-1. In FIG. 3, a lithium ion battery is assumed as the secondary battery 7-1, and the protection IC 11-1 is provided in the battery protection unit 11. In addition, the battery protection unit 11 includes a discharge control MOSFET 11-2, a voltage detection terminal protection resistor 11-3, a connection circuit 11-4 for transmitting a control output signal of the charge control MOSFET to the CPU 6-4, and 11-5, a resistor 11-6, and a capacitor 11-7.

  The connection circuits 11-4 and 11-5 are provided because it is necessary to perform overcharge protection of the lithium ion battery. That is, in the connection circuits 11-4 and 11-5, the CPU 6-4 needs to detect the overcharge detection by the protection IC 11-1, and control to turn off the switching unit 7-2 that is a MOSFET for charge control is necessary. Is provided. Note that FIG. 3 is an example of connection, and any configuration may be used as long as similar functions are satisfied.

  As described above, the switching unit 7-2 has both the function of switching the power feeding path during the switching charge control and the function of the charge control MOSFET. Normally, the charge control MOSFET is controlled from the output terminal of the protection IC 11-1. However, since the control function from the overdischarge state cannot be achieved with such a configuration, in this embodiment, the control function from the overdischarge state can be realized by connecting as shown in FIG.

  The voltage detection terminal of the protection IC 11-1 connected to the protection resistor 11-3 monitors the voltage difference from the terminal connected to the negative electrode of the secondary battery 7-1 and detects the direction and magnitude of the current. is doing. In the configuration of FIG. 3, the voltage detection terminal is connected between the discharge control MOSFET 11-2 and the switching unit 7-2 (charge control MOSFET). Although depending on the specification of the protection IC 11-1, the voltage detection terminal of the protection IC 11-1 is generally connected to the source side of the charge control MOSFET (switching unit 7-2).

  On the other hand, in the present embodiment, as will be described later, the charging control MOSFET (switching unit 7-2) is frequently turned ON / OFF regardless of the instruction of the protection IC 11-1. In such a configuration, when the electronic timepiece 100 is lowered from the charger 200 and the switching unit 7-2 is opened, a voltage corresponding to the voltage drop of the parasitic diode of the switching unit 7-2 is detected as a voltage. It occurs between the element and the negative electrode of the secondary battery 7-1. For this reason, it may be erroneously determined that an excessive current flows. For example, when the battery voltage has reached a level at which the discharge control MOSFET 11-2 is turned on, the protection IC 11-1 immediately turns off the discharge control MOSFET 11-2, so that there is a possibility of returning to the stop state again. .

  This state corresponds to a scene that is dropped from the charger 200 during the switching charge control. In such a case, the function is restored if it is placed on the charger 200 again, but this is not a preferable control. Therefore, in this embodiment, in order to avoid this phenomenon, the connection position of the voltage detection terminal of the protection IC 11-1 is changed. With this configuration, the voltage difference between the voltage detection terminal of the protection IC 11-1 and the negative electrode of the secondary battery 7-1 does not depend on ON / OFF of the charging control MOSFET (switching unit 7-2). Such a connection form deviates from the usage of the normal protection IC 11-1, but operates without inconvenience within the scope of the control method of the present embodiment.

  Next, the charging control processing by the electronic timepiece 100 according to the present embodiment configured as described above will be described with reference to FIGS. FIG. 4 is a flowchart showing the overall flow of the charging control process in the present embodiment. 5-7 is a figure showing the electronic timepiece 100 of a switching charge state. FIG. 8 is a diagram illustrating the electronic timepiece 100 in the switching charge end state. FIG. 9 is a diagram illustrating a change in voltage at a predetermined location during the switching charge control. FIG. 10 is a diagram showing the locations at which the voltages shown in FIG. 9 are measured. Note that the switching charge state refers to a state in which switching charge control is performed by the control unit 6. Further, the switching charge end state refers to a state where the switching charge control by the control unit 6 is ended.

  Here, the present embodiment is used in a scene where a product discharged to a level where the battery voltage of the secondary battery 7-1 falls below the lower limit value of the operating voltage of the control unit 6 is used. Hereinafter, the state in which the secondary battery 7-1 is discharged until it falls below the lower limit value of the operating voltage of the control unit 6 is referred to as an overdischarge state. In addition, the state of the electronic timepiece 100 in which the overdischarged secondary battery 7-1 is incorporated is referred to as an initial state. 2 described above represents the electronic timepiece 100 in the initial state.

  The electronic timepiece 100 in the initial state is in a state where it cannot perform any function (step S11). When the electronic timepiece 100 in such a state is placed on the charger 200 (step S12), the state of the electronic timepiece 100 immediately after being placed is the initial state (step S13). As shown in FIG. 2, since the power supply path is connected only to the capacitor 4-2, immediately thereafter, charging of the capacitor 4-2 is started. The voltage of the capacitor 4-2 increases instantaneously and is charged instantly. In this way, when the voltage of the capacitor 4-2 charged instantaneously reaches the lower limit value of the operating voltage, the control unit 6 is activated, and the switching charge control is immediately performed regardless of the battery voltage of the secondary battery 7-1. It shifts to the switching charge state which is a state to perform (step S14).

  Hereinafter, details of each state included in the switching charge state (step S14 in FIG. 4) will be described mainly with reference to FIGS.

  5 to 7 show the electronic timepiece 100 in the switching charge state. The switched charge state further includes a plurality of states in accordance with the progress of control. That is, according to the combination of the open / close state of the switching unit 7-2 that switches the power supply path of the secondary battery 7-1 and the open / close state of the switch unit 8-2 that switches the power supply path of the load unit 8-1. A state can exist. In the following, for convenience of explanation, an example constituted by the secondary battery 7-1 and one load unit 8-1 will be described. Even when the number of load units 8-1 is two or more, it is possible to realize control for switching a plurality of states by the same method.

  FIG. 5 shows a state in which the capacitor 4-2 is charged (hereinafter referred to as state A). FIG. 5 is the same as FIG. 2 showing the initial state in that the switching unit 7-2 and the switching unit 8-2 are open, but charging the capacitor 4-2 by being mounted on the charger 200. Is different.

  The control unit 6 does not start the operation immediately after the voltage of the capacitor 4-2 reaches the lower limit value of the operating voltage, but is determined in advance as the time until the capacitor 4-2 is sufficiently charged. The operation may be started after the waiting time has elapsed. The applied voltage to the capacitor 4-2 is preferably sufficiently higher than the lower limit value of the operating voltage of the control unit 6. However, since these are determined based on the balance between the capacitance of the capacitor and the current consumption of the control unit 6 and the like, the standby time and the applied voltage are not as good as possible, and the operation of the control unit 6 can be ensured for a certain time. It is sufficient if the electric charge can be accumulated in the capacitor 4-2.

  Since the standby time determined here is the time when power can be supplied to the secondary battery 7-1 and the load unit 8-1 described below, the capacity of the capacitor 4-2 is the type of the load unit 8-1 to be supplied, etc. Determine in consideration of However, it is better to set a value having a sufficient margin in consideration of a decrease in power due to a positional shift between the primary power transmission module 211 and the secondary power supply unit 1. The period of state A corresponds to the range of time t1 in FIG.

  After the state A in FIG. 5, the state transits to the state in FIG. FIG. 6 shows a state in which the secondary battery 7-1 is charged (hereinafter referred to as state B). As shown in FIG. 6, the control unit 6 controls the switching unit 7-2 so as to close the power supply path from the secondary power supply unit 1 to the secondary battery 7-1 to charge the secondary battery 7-1. To start.

  Here, when the power supply path switching means to the secondary battery 7-1 is connected, the voltage of the secondary power supply unit 1 in FIG. 4 drops to the vicinity of the battery voltage of the secondary battery 7-1 by the charging current. For this reason, the control unit 6 must consider that the voltage of the secondary power supply unit 1 falls below the lower limit value of the operating voltage of the control unit 6. That is, the control unit 6 performs control so that the secondary battery 7-1 is charged for a period until the voltage stored in the capacitor 4-2 falls below the operating voltage due to its current consumption.

  For example, the control unit 6 detects or calculates the voltage of the capacitor 4-2, and enters the secondary battery 7-1 during a period in which the voltage of the capacitor 4-2 is equal to or higher than a predetermined voltage threshold (first threshold). Control to charge. In this case, the control unit 6 controls the switching unit 7-2 to open a power supply path from the secondary power supply unit 1 to the secondary battery 7-1 when the voltage of the capacitor 4-2 becomes smaller than the threshold value. Then, the charging of the secondary battery 7-1 is stopped. Further, the control unit 6 is configured to charge the secondary battery 7-1 until a predetermined time (first time) elapses after the charging of the secondary battery 7-1 is started. May be. After this time has elapsed, the control unit 6 controls the switching unit 7-2 to open a power supply path from the secondary power supply unit 1 to the secondary battery 7-1 to charge the secondary battery 7-1. To stop.

  The voltage of the capacitor 4-2 may be detected by an A / D circuit, or may be calculated by a CR curve from the charging voltage of the capacitor 4-2. For example, when using the CPU 6-4 having a built-in A / D terminal, the A / D terminal may be used. In this case, there is a merit that the configuration for avoiding erroneous voltage detection as described above is unnecessary, but the selection range of the CPU 6-4 is limited. Therefore, a configuration in which the voltage of the capacitor 4-2 is predicted using a CR curve is preferable from the viewpoint of simplicity of configuration and cost.

  In this case, in order to improve the calculation accuracy, it can be said that it is a better configuration to give the capacitor 4-2 a potential that is made constant by a Zener diode or a regulator. This can be realized by using the constant voltage unit 3 as shown in FIG. When the no-load voltage of the secondary power supply unit 1 is higher than the withstand voltage of other components, it is necessary to protect by means such as the constant voltage unit 3. The period of state B corresponds to the range of time t2 in FIG.

  In terms of control, the next transition is to FIG. 5 or FIG. When charging the capacitor 4-2 that has decreased during the charging period of the secondary battery 7-1, the process proceeds to FIG. If the voltage of the capacitor 4-2 is within a range that does not stop the control unit 6, the transition to FIG. Further, when power can be secured and operation is possible, the state transitions to a state (not shown) in which both the secondary battery 7-1 and the load unit 8-1 are supplied with power simultaneously by combining FIGS. Also good. FIG. 9 shows an example of voltage change when the capacitor 4-2 is recharged once again as a typical example.

  Returning to FIG. 5, after charging the capacitor 4-2, the state transitions to the state of FIG. FIG. 7 shows a state where power is supplied to the load unit 8-1 (hereinafter referred to as state C). Also in the state C, the voltage drop of the secondary power supply unit 1 occurs due to the current flowing to the load unit 8-1 as in the case of charging the secondary battery 7-1 (state B). For this reason, the control unit 6 performs control so that power is supplied to the load unit 8-1 until the voltage stored in the capacitor 4-2 falls below the operating voltage. The current flowing through the load unit 8-1 is set to an appropriate value in consideration of the power generated by the secondary power supply unit 1. The period of state C corresponds to the range of time t3 in FIG.

  Thereafter, the control unit 6 controls the charging and the operation of the load unit 8-1 so as to alternately repeat the period from t1 to t3 as shown in FIG. Note that the control order need not be limited to the order from t1 to t3. For example, an order in which the period of t3 is intermittently driven and t1 is inserted therebetween is also possible. Further, only the combination of t1 and t2 may be repeated, and the period of t3 may be provided only once in a predetermined period (for example, several minutes).

  During the control, the capacitor 4-2 has an operating point voltage determined by the secondary power source unit 1, and the secondary battery 7-1 or the load unit 8-1, and the secondary power source. Charging / discharging is repeated with the no-load voltage of unit 1 (or a voltage obtained by making the no-load voltage constant). Since the time t1 required to charge the capacitor 4-2 decreases as the voltage of the secondary battery 7-1 increases, the power supply time t2 to the secondary battery 7-1 can be relatively extended.

  Such control is performed by adjusting the duty ratio between the charging of the secondary battery 7-1 and the charging of the capacitor 4-2 within the range in which the voltage of the capacitor 4-2 does not fall below the operating voltage of the control unit 6, and the control time width. It is possible to devise various things, such as change.

  Returning to FIG. 4, the reset unit 5 determines whether or not the voltage of the capacitor 4-2 is lower than the operating voltage of the control unit 6 during the switching charge control (step S15). When the voltage of the capacitor 4-2 is smaller than the operating voltage (step S15: Yes), the reset unit 5 resets the operation of the control unit 6 (circuit reset).

  As described above, the control unit 6 controls charging so that the voltage of the capacitor 4-2 does not fall below the operating voltage. However, for some reason, the voltage of the capacitor 4-2 may be lower than the operating voltage of the control unit 6. In such a case, the reset unit 5 resets the entire circuit and returns the circuit connection to the initial state (step S13).

  As described above, the circuit reset includes the reset unit 5 that fixes the potential of the CPU 6-4 to the L level when the voltage of the control unit 6 becomes a predetermined value (control unit reset voltage) or less, and This can be achieved by configuring the switching unit 8-2 that switches the power supply path of the load unit 8-1 with an Nch MOSFET or a transistor.

  With such a configuration, (1) start-up of the control unit 6, (2) switching charge control, (3) accidental voltage drop, (4) the voltage of the control unit 6 decreases and falls below the control unit reset voltage. 5) The reset unit 5 sets the voltage of the control unit 6 to the L level, (6) the output signal level of the control unit 6 = L level, (7) the Nch MOSFET or the transistor is turned off, and (8) the load unit 8-1. A loop of power supply stop, (9) start of charging the capacitor 4-2, (10) activation of the control unit 6 (= (1) above), etc. occurs. That is, even if the voltage of the capacitor 4-2 falls below the operating voltage of the control unit 6 during the switching charge control, the control unit 6 can be operated again, so that a highly reliable control circuit can be configured. it can.

  If at least such a configuration is provided, the control unit 6 controls the switching unit 7-2 and the switching unit 8-2 so that the voltage of the capacitor 4-2 falls within the time range below the operating voltage. do not have to. However, only the method by the circuit reset may cause a time loss for restarting the CPU 6-4 and a non-control state during that time. For this reason, in this Embodiment, it is comprised so that it may electrically feed to the load part 8-1 in the time when the voltage of the capacitor | condenser 4-2 is not less than the operating voltage of the control part 6. FIG.

  When the voltage of the capacitor 4-2 is equal to or higher than the operating voltage in step S15 (step S15: No), the control unit 6 determines whether or not the voltage (battery voltage) of the secondary battery 7-1 is equal to or higher than the switching charge release voltage. Is determined (step S16). When the battery voltage is not equal to or higher than the switching charge release voltage (step S16: No), the control unit 6 continues the switching charging control (step S14).

  When the battery voltage is equal to or higher than the switching charge release voltage (step S16: Yes), the control unit 6 ends the switching charge control and transitions to the switching charge end state (step S17). When charging is completed in the switching charging end state (when the electronic timepiece 100 is placed on the charger 200), the charging of the secondary battery 7-1 is continued (step S18).

  FIG. 8 shows the electronic timepiece 100 in the switching charge end state. It is not necessary to switch the power supply path from the secondary power supply unit 1 to the secondary battery 7-1 after the battery voltage becomes equal to or higher than the switching charge release voltage. The switching charge release voltage may be set to be equal to or higher than the lower limit value of the operating voltage range of the control unit 6. Note that the switching charge release voltage needs to be set according to the components constituting the control unit 6. For example, when the control unit 6 is configured only by the CPU 6-4, the lower limit value of the operation range of the CPU 6-4 may be set as the switching charge release voltage. In addition, when the reset unit 5 that fixes the potential of the CPU 6-4 to the L level when the voltage of the control unit 6 becomes equal to or lower than a predetermined voltage (control unit reset voltage), the switching charge release voltage is the reset unit. Must be greater than 5 H level return voltage. When the protection IC 11-1 is provided, the switching charge release voltage must be equal to or higher than the voltage at which the discharge control MOSFET 11-2 is turned on. When the secondary battery 7-1 is a lithium ion battery, a configuration including the protection IC 11-1 is more preferable.

  However, when the protection IC 11-1 is used, the voltage drop of the parasitic diode of the discharge control MOSFET 11-2 is added to the detected voltage value during the period when the discharge control MOSFET 11-2 is open. The switching charge release voltage must be set in consideration of the above.

  The switching charge control is also ended when the charge detection unit 10 detects that no power is supplied from the secondary power supply unit 1. For example, the case where the power plug 212 of the charger 200 is removed from the outlet, the case where the electronic timepiece 100 is removed from the charger 200, and the case where the electronic timepiece 100 is accidentally dropped from the charger 200 may be applicable. .

  In FIG. 4, step S <b> 21 corresponds to the situation where the switching charging state is changed to the switching charging end state in this way. The situation in which the electronic timepiece 100 is removed from the charger 200 can occur in any state. Steps S19 and S23 in FIG. 4 correspond to the case of being removed in the initial state and the case of being removed in the switching charge end state, respectively.

  In FIG. 4, for convenience of explanation, the charging start (start of power supply from the secondary power supply unit 1) and the end of charging (end of power supply from the secondary power supply unit 1) to the charger 200, respectively. It was expressed that it was put on and removed from the charger 200. This is because the charger 200 generally used for non-contact charging is a sheet type or a cradle type, and charging can be performed by placing a secondary product (electronic timepiece 100) on it. However, depending on the form of the charger 200 for non-contact charging, fitting / disconnecting, connection / disconnection, and the like may correspond to the start / end of charging.

  When the electronic timepiece 100 in the initial state is not placed on the charger 200 (in the case of “no charge” on the right in FIG. 4), the switching charge control is not executed, and the transition to the switching charge end state is made (step S24). Next, the control unit 6 determines whether or not the voltage (battery voltage) of the secondary battery 7-1 is equal to or higher than the operating voltage of the control unit 6 (step S25). When the battery voltage is not equal to or higher than the operating voltage (step S25: No), the switching charge end state is maintained while the voltage of the capacitor 4-2 is equal to or higher than the operating voltage, but thereafter the initial state is restored (step S11). When the battery voltage is equal to or higher than the operating voltage (step S25: Yes), the control unit 6 continues to operate using the secondary battery 7-1 as a power source (step S26).

  In addition, although the state which performs the process of step S24 and step S25 exists as a transient state for a very short time, in fact, it immediately shifts to the next state.

  When the electronic timepiece 100 is put on the charger 200 in the switching charging end state in step S24 (step S20), the state transits to the switching charging state (step S14). In addition, when the electronic timepiece 100 is put on the charger 200 in the switching charging end state in step S26 (step S22), after the transition to the switching charging end state in step S17, the secondary battery 7-1 is charged. Continue (step S18).

  FIG. 9 shows a change in voltage during the switching charge control. The solid line (V1) in FIG. 9 corresponds to the voltage supplied from the secondary power supply unit 1 as shown in FIG. The broken line (V2) in FIG. 9 corresponds to the voltage supplied from the capacitor 4-2 to the control unit 6 as shown in FIG. As described above, since time t1 in FIG. 9 represents the state A in which the capacitor 4-2 is charged, V2 increases. Thereafter, the control unit 6 transitions to the state B, and charges the secondary battery 7-1 for a time during which V2 does not fall below the lower limit value of the operating voltage of the control unit 6 (time t2).

  FIG. 9 shows an example of control for supplying power to the load unit 8-1 (state C, time t3) after repeating time t1 (state A) and time t2 (state B). .

  It is preferable that the control part 6 operates the light load part 8-1 intermittently as much as possible. Further, when the control unit 6 makes the drive waveform finer, the merit may increase. For example, when the LED that is the load unit 8-1 is lit for 1 second, it is always lit for 1 second. In this case, although depending on current consumption of the CPU 6-4 and the like, it is necessary to prepare a capacitor 4-2 having a capacity capable of holding power for lighting the LED for 1 second.

  Therefore, the control unit 6 is configured to control with a drive waveform having a cycle of 10 ms, for example, lighting for 7 ms (power consumption of the capacitor 4-2) and extinguishing for 3 ms (charging the capacitor 4-2). Thereby, the capacity | capacitance of a capacitor | condenser should just be able to light LED for 7 ms. In this example, if lighting for 7 ms can be maintained, the LED can theoretically be lit for any number of seconds. Although it is actually intermittent driving, it is because the light of the LED seems to be lit continuously because the cycle is short.

  Since the lighting duty is 70%, the brightness decreases. However, there are merits in that the capacity of the capacitor can be reduced, the lighting time can be extended, and the operating voltage margin can be secured by suppressing the voltage drop of the capacitor 4-2.

  FIG. 11 is a diagram illustrating the transition of various voltages when charged from an overdischarged state by the control as described above. Note that the dotted line (battery voltage ') in FIG. 11 represents the voltage detected by the battery voltage detector 9 as a value higher by the voltage drop of the parasitic diode. FIG. 11 shows an example in which the protection IC 11-1 turns off the discharge control MOSFET 11-2 at 2.5V (overdischarge detection voltage) and stops the power supply to the circuit. Thereby, the control part 6 is dropped to L level by the reset part 5 (2.4V detection). Note that the set voltage described in FIG. 11 is an example.

(Modification)
A blue LED or a white LED has a characteristic that current starts to flow from 3.0 V or higher. For this reason, even if the battery voltage is at a level at which the control unit 6 can be operated, there may be a case where the voltage is still low to light such an LED. Therefore, when operating such a load unit 8-1, the control unit 6 is configured so that the secondary battery 7-1 is disconnected from the circuit and the load unit 8-1 is directly operated by the power of the secondary power supply unit 1. It may be configured. Thereby, the operating current of the load unit 8-1 can be ensured with a higher voltage.

  As described above, in the charging control device according to the present embodiment, a power storage unit (capacitor or the like) having a charging time shorter than that of a power storage unit (secondary battery, electric double layer capacitor, or the like) that supplies power for operating a product is used. By using it, the control unit can be operated more quickly even when a voltage drop of the secondary power supply occurs due to the charging current of non-contact charging.

  For this reason, for example, even if the case contains metal, such as an electronic watch, and the voltage of the secondary battery or the like drops below the operating voltage of the circuit, the CPU control is performed from the moment when the battery is put on the charger. The charging display can be obtained.

  Further, as a load unit controlled by the control unit, in addition to a display unit (LED or the like) that displays a charging state, a hand moving unit that moves the hands of an electronic timepiece, a resonance frequency control circuit, a positional deviation detection circuit, and information communication A circuit or the like can also be used. Thereby, regardless of the voltage state of the on-board battery, it is possible to execute the hand movement, the resonance frequency control, the positional deviation detection control, and the information communication between the primary and secondary coils from the moment when the battery is put on the charger. .

  In addition, by providing the electronic timepiece with the charge control device of the present embodiment, it is possible to charge efficiently even when the casing contains metal.

DESCRIPTION OF SYMBOLS 1 Secondary power supply part 1a Secondary coil 1b Magnetic core 2 Rectification / smoothing part 3 Constant voltage part 4-1 Backflow prevention element 4-2 Capacitor 5 Reset part 6 Control part 6-1 Voltage regulator IC
6-2, 6-3 External capacitor 6-4 CPU
6-5-6-7 Resistance 7-1 Secondary battery 7-2 Switching unit 8-1 Load unit 8-2 Switching unit 9 Battery voltage detection unit 10 Charging detection unit 10-1 MOSFET
10-2 Resistance 10-3 Diode 11 Battery Protection Unit 11-1 Protection IC
11-2 MOSFET for discharge control
11-3 Protection resistance 11-4, 11-5 Connection circuit 11-6 Resistance 11-7 Capacitor 100 Electronic clock 200 Charger 211 Power transmission module 212 Power plug 213 Magnetic body core 214 Primary coil 215 Oscillation circuit 216 Power supply circuit

Claims (17)

A secondary power source that generates power by electromagnetic induction in response to a magnetic field generated by the primary power source;
A first power storage unit charged with the generated electric power;
A second power storage unit that is charged with the generated power and is charged to a predetermined specified value, and is smaller than the first power storage unit;
It operates when the voltage of the second power storage unit exceeds the specified value, and controls the charging of the first power storage unit by opening and closing the first power supply path from the secondary power supply unit to the first power storage unit. A control unit;
A charge control device comprising: The second power storage unit is charged with the generated power when the first power supply path is open,
The controller repeats the process of opening the first power supply path and charging the second power storage unit, and the process of closing the first power supply path and charging the first power storage unit, thereby Controlling charging of the power storage unit,
The charge control device according to claim 1, wherein: The control unit opens the first power feeding path to stop charging the first power storage unit when a voltage of the second power storage unit becomes smaller than a predetermined first threshold;
The charge control device according to claim 2, wherein: The control unit opens the first power supply path when a predetermined first time has elapsed after closing the first power supply path and starting charging the first power storage unit. Stop charging the
The charge control device according to claim 2, wherein: A voltage detection unit for detecting a voltage of the first power storage unit;
The controller is configured to fix the first power feeding path in a closed state when the detected voltage exceeds a predetermined second threshold;
The charge control device according to claim 1, wherein: The control unit fixes the first power supply path in a closed state when a predetermined second time elapses from the start of operation and the detected voltage exceeds the second threshold. ,
The charge control device according to claim 5. A reset unit that resets the operation of the control unit when a voltage supplied to the control unit is equal to or lower than a predetermined third threshold;
A switching unit that opens the first power supply path when the operation of the control unit is stopped,
The charge control device according to claim 1, wherein: A load unit that operates by the power generated by the secondary power source unit;
The control unit further controls the operation of the load unit by opening and closing a second power supply path from the secondary power supply unit to the load unit;
The charge control device according to claim 1, wherein: The controller, when closing the second power feeding path and operating the load unit, opens the first power feeding path and stops charging the first power storage unit;
The charge control device according to claim 8. The load unit is a display unit for displaying a charge state of the first power storage unit;
The charge control device according to claim 9. The display unit is an LED (Light Emitting Diode);
The charge control device according to claim 10. The load portion is a hand moving portion for moving a hand for displaying time;
The charge control device according to claim 9. The load unit is a frequency detection unit for detecting a frequency of AC power generated in the secondary power supply unit, and a frequency adjustment unit for electrically adjusting a resonance frequency of the secondary power supply unit. ,
The charge control device according to claim 9. The load unit is a position detection unit that detects a shift in position between the primary power source unit and the secondary power source unit;
The charge control device according to claim 9. The load unit is a communication unit that communicates information between the primary power source unit and the secondary power source unit;
The charge control device according to claim 9. The second power storage unit is a capacitor,
Further comprising a diode for preventing current backflow of the capacitor;
The charge control device according to claim 1, wherein:   An electronic timepiece comprising the charge control device according to claim 1.

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