JP2003224979A - Power supply device and portable electronic device - Google Patents

Abstract

(57) [Problem] To provide a power supply device capable of greatly improving the rectification efficiency of a power generation device that can be built into an arm-mounted electronic device. The power supply device according to the present invention includes a diode, a bypass switch connected in parallel to the diode, and a control unit that turns on the bypass switch when a forward voltage is generated in the diode. Rectification or backflow prevention from the power generator built into portable electronic devices such as wrist-worn type, using the power supply unit, it is possible to almost eliminate the loss associated with the forward voltage during power supply .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a power supply device equipped with a power generator such as a type that can be stored in a portable electronic device such as a wrist-worn type and that can convert the kinetic energy of the body into an alternating current by using the motion of a rotary weight. It is about.

[0002]

2. Description of the Related Art In a small and portable electronic device such as a wristwatch device, a portable electronic device in which a battery is replaced or the battery itself can be eliminated by incorporating a power generator is devised and put into practical use. Has been converted. FIG. 11 shows, as an example thereof, a schematic configuration of a wristwatch device 10 incorporating the power generator 1. In this portable electronic device (wristwatch device) 10, a rotary weight 13 that makes a turning motion in the case of the wristwatch device, a train wheel mechanism 11 that transmits the rotary motion of the rotary weight 13 to an electromagnetic generator, and an electromagnetic generator. 1
2 includes a rotor 14 and a stator 15, and when the two-pole magnetized disk-shaped rotor 14 rotates, an electromotive force is generated in the output coil 16 of the stator 15,
AC output can be taken out. Further, the power supply device 20 of the portable electronic device includes a rectifier circuit 24 that can rectify the alternating current output from the power generation device 1 and supply the rectified alternating current to the large-capacity capacitor 5 and the processing device 9, and its output side. A large-capacity capacitor 5 which is a charging device and a processing device 9 are connected. Therefore, the processing device 9 connected to the power supply device 20 uses the power of the power generation device 1, or
The timekeeping function 7 and the like mounted therein can be operated by the electric power discharged from the large-capacity capacitor 5. For this reason,
In this portable electronic device, the processing device 9 can be continuously operated without a battery, the processing device can be used anytime and anywhere, and the problem associated with battery disposal can be eliminated. Equipment.

In the electronic device shown in FIG. 11, since the electric power supplied from the built-in power generator 1 is AC power, it is rectified by the rectifier circuit 24 of the power supply device 20 and then charged in the large-capacity capacitor 5, In addition, it becomes the operating power of the processing device 9 including an IC and the like. In the power supply device 20 shown in FIG. 11, the power that has been half-wave rectified using the two diodes 25 and 26 is used as the auxiliary capacitor 2
A rectifier circuit 24 is used that can temporarily charge the battery 7 and perform boost rectification. Silicon diodes are used as the diodes 25 and 26, and as shown in FIG. 12, there is a forward voltage Vf of about 0.5 to 0.6 V with respect to the forward current If. Therefore, the electric power W1 obtained by rectifying the electric power W0 supplied from the power generation device 1 by the rectifying circuit 24 is as follows because there is a loss of the forward voltage Vf of the diode forming the rectifying circuit 24.

W1 = ηc × W0 (1) ηc = V1 / (V1 + 2 × Vf) (2) where ηc is the rectification efficiency during charging and V1 is the output voltage from the rectifier circuit. In the circuit shown in FIG. 11, this corresponds to the charging voltage of the large capacity capacitor 5.

As for the operating voltage of the processing device 9 of portable electronic equipment such as a wristwatch device, ICs are being driven at a lower voltage in order to reduce power consumption. For example, 0.9 to 1.
It is possible to start at about 0V. Therefore,
The voltage of the large-capacity capacitor 5 is selected to be about 1.5 to 2 V. On the other hand, considering the forward voltage Vf of about 0.5 to 0.6 V, the rectification efficiency ηc is about 0.6. turn into. Therefore, it is desirable that the forward voltage Vf be low in order to improve the rectification efficiency ηc.

As a power generator that can be built into a portable electronic device, a device that captures movements of a body or the like using a rotary weight to rotate a rotor to convert it into AC power, and energy is stored using a mainspring. Then, there are a device for converting to AC power, a device for vibrating a piezoelectric element by body movement or the like to obtain AC power, a device for obtaining DC power using a thermoelectric element or a solar cell, and the like. Among these, in a power generator that can obtain AC power, the kinetic energy obtained for power generation from movement of the body is small, and since the power generator itself is built in a portable electronic device, the power generator itself is also extremely miniaturized. Since the electromotive voltage is small, it also fluctuates greatly due to body movements, etc., and it is not always possible to obtain electric power. Therefore, the input voltage of the rectifier circuit is low, fluctuates at a voltage close to the forward voltage Vf, and reaches at most several times the forward voltage Vf. Therefore, by lowering the forward voltage Vf, the power supply efficiency is significantly improved.

Even in a power supply device using a power generator that generates direct-current power such as a solar cell, the electromotive voltage greatly varies depending on the illuminance and the like. Therefore, by reducing the forward voltage Vf of the diode for blocking the reverse current, the generated power can be effectively used even in a state where the illuminance is low and the electromotive voltage is small. As described above, in order to effectively use the electric power from the power generator that can be built in the portable electronic device, which has been developed in recent years, it is important to lower the forward voltage Vf used in the supply circuit. It is an issue.

Therefore, in the present invention, a unidirectional unit capable of lowering the forward voltage Vf is adopted in place of the diode, whereby the rectification efficiency ηc of the power supply device for portable electronic equipment is significantly improved, An object is to provide a power supply device with high power supply efficiency. It is an object of the present invention to provide a portable electronic device that can be used anytime and anywhere without replacing the battery by mounting such a high-efficiency power generation device together with a processing device.

[0009]

DISCLOSURE OF THE INVENTION Therefore, in a power supply device that can be incorporated in a portable electronic device of the present invention, a diode and a diode connected in parallel to the diode are provided in a supply unit that supplies power from a power generation device to a charging device or a processing device. The unidirectional unit includes a bypass switch connected to the switch and a control unit that turns on the bypass switch when a forward voltage is generated in the diode. In this unidirectional unit, when a current flows in the forward direction of the diode and a forward voltage is generated, the bypass switch is turned on, so that the loss due to the forward voltage can be prevented. When the current flows in the reverse direction of the diode, a voltage having a reverse polarity to the forward voltage is generated, so the bypass switch is not turned on and the diode can prevent the reverse current.

A field effect transistor is one that can be easily used as such a unidirectional unit, a field effect transistor functions as a bypass switch, and a parasitic diode of the bypass switch functions as a diode.

Furthermore, when using a power generator that captures energy around the user to generate power, such as a solar cell or a power generation system having a rotary weight employed in a wristwatch device, the power generator continues to operate. There is little to do. Therefore, it is desirable to be able to control the voltage supplied from the charged large-capacity capacitor or the voltage higher than the output voltage of the power generation device boosted by the booster circuit. By enabling control at a voltage higher than the output voltage of the power generator, the switching operation can be reliably performed at high speed even when the output voltage at the initial or final stage of power generation is low, so that the rectification efficiency can be further increased.

Since the forward voltage of such a unidirectional unit is lowered by turning on the bypass switch, it is desirable to detect the direction of the current by a different method in order to turn off the bypass switch. For example, after the control unit turns on the bypass switch and turns off the bypass switch after a lapse of a predetermined time, the presence or absence of the forward voltage can be detected (sampling), and the direction of the current can be determined. Therefore, the presence or absence of the forward voltage is periodically detected, and when the forward voltage is present, the bypass switch is turned on again to reduce the loss of the forward voltage and prevent the reverse current flow.

Further, a comparator may be provided in the control section as a comparing means for comparing the voltages across the diodes, and while the bypass switch is on, the voltage drop due to the bypass switch may be detected to detect the direction of the current. It is possible. It is also possible to connect a minute resistor in series with the bypass switch in order to generate a voltage drop that can be detected by the comparator. In this way, by adopting the unidirectional unit that controls the bypass switch depending on whether or not the forward voltage is generated in the diode, the unidirectional unit is based on the power generation state of the power generation device without increasing the interface with the power generation device. Can be controlled. Therefore, since a coil for detecting electromotive voltage is not required in the power generator itself, without complicating the structure of the power generator,
It is possible to perform control to eliminate loss due to forward voltage without increasing the number of interfaces with the power generator.

Further, in order to exert the performance as a unidirectional unit in a state where electric power for controlling the bypass switch is not obtained, it is desirable to adopt an enhancement type field effect transistor as the bypass switch. By adopting the enhancement type, since the bypass switch is turned off when the gate voltage is not applied, the diode can be used to prevent the reverse flow as the unidirectional unit.

When AC power is supplied from the generator, such a unidirectional unit for rectifying the AC power can be used in the supply section of the power supply to reduce the loss due to the forward voltage of the diode. . In particular, since the electromotive force of the power generator that can be built in the portable electronic device is low and is close to the forward voltage of the diode, it is possible to significantly improve the rectification efficiency and provide a power supply device with high power supply efficiency. .

When full-wave rectification is performed in the supply unit,
Instead of a diode, four unidirectional units may be used, but first and second input terminals connected to the generator and first and second output terminals connected to the charger or the processor. To the first and second input terminals and the first output terminal, the first and second unidirectional units are connected in parallel, and the first and second input terminals and the second output terminal are connected. The first and second field effect transistors can be connected in parallel between the two. A first conductivity type field effect transistor is adopted as the first and second unidirectional units. On the other hand, the first and second field effect transistors adopt the second conductivity type, and the voltage of the second input terminal is applied to the gate input of the first field effect transistor, and the second field effect transistor is applied. The voltage of the first input terminal is applied to the gate input of the effect transistor. As a result, the first and second field-effect transistors are turned on and off together with the unidirectional unit by the voltage change of the first and second input terminals, so that the loss due to the forward voltage is eliminated and the power supply efficiency can be significantly improved.

By connecting a driving element such as an inverter to the gate inputs of the first and second field effect transistors of the second conductivity type, it is possible to improve the accuracy of the timing at which the field effect transistor is turned on. . Also,
As a control unit for the first and second unidirectional units, the voltages of the first and second input terminals and the first and second input terminals are set so that the forward voltage can be collectively determined for each unidirectional unit.
It is also possible to provide a three-input comparator that compares the voltages of the output terminals of, and the total number of comparators can be reduced. As a result, the power consumption of the semiconductor device that realizes the power supply circuit can be reduced. Further, since the circuit is simplified, the area of the semiconductor device is reduced and the cost is reduced.

Further, also in the power supply device having the power generation device for supplying the DC power, the loss due to the forward voltage of the diode can be reduced by adopting the above unidirectional unit in order to prevent the backflow. That is, by adopting the above-described unidirectional unit, it is possible to prevent the loss due to the forward voltage of the diode during power generation. Also,
It is also possible to prevent backflow to the power generation device when no power is being generated or when the electromotive force is lower than that of the charging device.

As described above, the power supply device of the present invention can be incorporated in a portable electronic device such as a wrist-worn electronic device, and outputs AC power using an electromagnetic generator or a piezoelectric element. And a power generation device that outputs DC power such as a solar cell or a thermoelectric element, and the power from these power generation devices can be supplied to the charging device and the processing device with little loss. These power generators capture the movements and vibrations of the user's body to generate electricity,
It is a portable device that can convert discontinuous energy in the natural world such as sunlight and temperature difference into electric energy, but it cannot continuously obtain electric power and has a small electromotive force or current density. Therefore, the power supply device of the present invention can prevent power loss due to the forward voltage of the diode, which is almost equal to the electromotive force of the power generation device, and can prevent rectification or reverse current, and can supply power to the charging device and the processing device. It is very useful as a power supply device for electronic devices. Therefore, by using the power supply device of the present invention, a full-scale portable electronic device such as a wrist-worn type equipped with a processing device having a timekeeping function and the like can be provided with a processing function such as a timekeeping function anytime, anywhere. It is possible to provide electronic devices that can be demonstrated.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] The present invention will be described in more detail with reference to the drawings. FIG. 1 shows an outline of an electronic device including a power generation device according to the present invention. Power supply device 2 for electronic device 10 of this example
0 can be housed in a wristwatch device as described with reference to FIG. 11 and can supply AC power, and a processing device 9 such as a timing device that rectifies the power input from the power generation device 1. The rectifier circuit 24 for supplying the The first output end 22 and the second output end 23 of the power supply device 20 of the present example are connected to the large-capacity capacitor 5 and the processing device 9, which are charging devices, respectively, and the processing device 9
In addition to the one having the above-mentioned clock function, the one having a function of a radio, a pager, a personal computer or the like may be used.

Rectifier circuit 24 of power supply device 20 of this example
Is an auxiliary capacitor 27 and two unidirectional units 3
0 and 31 are provided so that boost rectification can be performed. In addition, the wristwatch device 10 of this example has a high-voltage side V
dd is grounded to be the reference voltage. Therefore, in the following, the low voltage side Vss is referred to as the output voltage, and the voltage values are all expressed as absolute values for simplicity.

The unidirectional units 30 and 31 used in the rectifier circuit 24 of this example are p-channel MOSFET 32 and n-channel MOSFET 33, respectively.
And the parasitic diodes 34 and 35 of these MOSFETs 32 and 33 are used as diodes for passing a current in one direction. Also MOSFET
Each unidirectional unit 30 and 31 comprises a control circuit 36 and 37, which detects the source (S) and drain (D) voltages of 32 and 33 and supplies a control signal to the gate (G 1).

First, the unidirectional unit 30 is configured so that the auxiliary capacitor 27 can be connected in parallel to the power generator 1, and the diode 34 of the unidirectional unit 30 half-wave rectifies the AC power to charge the auxiliary capacitor 27. Used. In the circuit of this example, the p-channel MOSFET 32
The source side 32S of is connected to the grounded Vdd side,
The drain side 32D is connected to the auxiliary capacitor 27 side. Therefore, the parasitic diode 34 in the forward direction from the drain 32D to the source 32S can be used for half-wave rectification, and the generated voltage V0 on the Mss side of the power generator 1 is higher than the ground voltage Vdd (in the positive direction). ), The auxiliary capacitor 27 can be charged.

The configuration and operation of each unidirectional unit 30 and 31 in the rectifier circuit 24 of this example will be described below with reference to the timing chart shown in FIG.
First, the MOSFET 3 forming the unidirectional unit 30
2 controls the voltage V on the source side 32S.
Comparator 41 that compares 3 and the voltage V2 on the drain side 32D, and the output of this comparator 41 is inverted and MO
Inverter 45 applied to the gate 32G of the SFET 32
Is equipped with. The voltage V3 on the source side is input to the inverting input 42 of the comparator 41, and the voltage V2 on the drain side is input to the non-inverting input 43. Diode 34
When a current flows from the drain side 32D in the forward direction to the source side 32S, a forward voltage Vf is generated in the diode 34. Therefore, the voltage V2 on the drain side becomes higher than the voltage V3 on the source side, and the output 4 of the comparator 41
4 outputs a high level signal. This high level signal is inverted by the inverter 45 and applied to the gate electrode 32G as a low level or negative potential signal. As a result, the p-channel MOSFET 32 is turned on, bypassing the parasitic diode 34 and turning on the MOSF.
Current flows through the channel formed in ET32. Therefore, since the voltage drop due to the forward voltage Vf of the diode 34 disappears, the voltage V3 on the source side rises to near the voltage V2 on the drain side, and the loss due to the forward voltage Vf can be reduced. However, since there is a voltage drop due to the channel formed in the MOSFET 32, the voltage V3 on the source side is kept lower than the voltage V2 on the drain side. The comparator 41 of this example has such an accuracy as to detect such a potential difference, and can keep the MOSFET 32 turned on while the current flows from the drain 32D to the source 32S in the MOSFET 32.

Alternatively, when the comparator 41 has a detection voltage hysteresis and a forward current flows through the diode 34 and a forward voltage Vf is generated to generate a potential difference of a certain level or more between the non-inverting input 43 and the inverting input 42. A high-level signal is output to the output 44 of the comparator 41, and the comparator 41 is switched so that the output 44 of the comparator 41 switches to the low-level signal when a predetermined potential difference smaller than the constant level potential difference or a negative potential difference occurs. It is also possible to configure. In this way MOSFET3
By providing a difference (hysteresis) in the detection voltage for turning on / off 2, it is possible to configure the MOSFET 32 with a switch with a smaller channel voltage drop, and further with an ideal switch with no voltage drop,
It is possible to further improve the rectification effect.

Referring to the timing chart of FIG. 2,
When the voltage V0 ′ generated when the generator 1 is unloaded is at a high level at time t11, that is, when Vss is higher than the ground potential Vdd, a current flows through the diode 34 and a voltage drop occurs due to the forward voltage of the diode. This allows MOS
The voltage (V2-V3) across the FET 32 is on the drain side 32
When the voltage V2 of D becomes higher and is detected by the comparator 41 at time t12, the output 4 of the comparator 41
4 becomes high level. Therefore, p-channel MOSFE
Since T32 is turned on, the voltage (V2-V3) across the unidirectional unit 30 does not reach the forward voltage Vf of the diode, and as shown in the figure, a minute voltage of several tens of mV due to the channel of the MOSFET 32. The descent will occur. Since a current flows through the unidirectional unit 30, the auxiliary capacitor 27 is charged and the voltage (V0-V2) across it is gradually increased.

At time t13, the AC power V of the power generator 1
When 0 ′ starts to decrease, electric charge starts to be discharged from the auxiliary capacitor 27 charged to the peak voltage Vc. When the discharge from the auxiliary capacitor 27 starts, the voltage V2 on the drain side 32D becomes lower than the voltage V3 on the source side 32S, so that the output of the comparator 41 becomes low level. For this reason,
The high-level signal inverted by the inverter 45 is supplied to the gate electrode 32G of the p-channel MOSFET 32, and the p-channel MOSFET 32 is turned off.
Further, when the voltage V3 on the source side becomes higher than the voltage V2 on the drain side, the voltage in the reverse direction is also applied to the diode 34. Therefore, no current flows through the diode 34. Therefore, the unidirectional unit 30 is turned off, the discharge from the auxiliary capacitor 27 is blocked, and after time t13, the voltage across the MOSFET 32 is the sum of the voltage V0 ′ generated by the generator and the voltage Vc (the polarity is If they are opposite, a difference will appear.

At time t14, when the phase of the AC power V0 'changes and the generated voltage V0 becomes lower (minus side) than the ground voltage Vdd, the auxiliary capacitor 27 is connected in series by the unidirectional unit 31. . Another unidirectional unit 31 used in the rectifier circuit 24 of this example
Is capable of connecting the auxiliary capacitor 27 in series to the power generation device 1, half-wave rectifying the AC power by the diode 35 thereof, and further applying the voltage charged in the auxiliary capacitor 27 to the output terminals 22 and 23. It can be supplied. Therefore, the AC power generated by the power generation device 1 by the power supply device 20 of this example is doubled as DC power, and the large capacity capacitor 5 connected to the output end 22 and the processing circuit connected to the output end 23. 9 is supplied.

In the rectifier circuit 24 of this example, the second 1
The directional unit 31 is an n-channel MOSFET 3
3 is adopted, and the source side 33 of the MOSFET 33 is
S is connected to the output ends 22 and 23 side, and the drain side 33D is connected to the auxiliary capacitor 27 side. Therefore, the parasitic diode 35, which is in the forward direction from the source 33S to the drain 33D, can be used for half-wave rectification, and the auxiliary capacitor 27 is charged when the generated voltage V0 becomes lower than the ground voltage Vdd. In addition to the electric power, the electric power generated by the power generation device 1 can be supplied to the output ends 22 and 23.

The control circuit 37 for controlling the MOSFET 33 includes a voltage V1 on the source side 33S and a drain side 33D.
Is provided with a comparator 41 for comparing the voltage V2 of the MOSFET 3 with an output 44 of the comparator 41.
3 is applied to the gate 33G. The voltage V2 on the drain side is applied to the inverting input 42 of the comparator 41.
Is input, and the voltage V1 on the source side is input to the non-inverting input 43. When a current flows from the source side 33S in the forward direction of the diode 35 to the drain side 33D, a forward voltage Vf is generated in the diode 35. For this reason,
The voltage V1 on the source side becomes higher than the voltage V2 on the drain side, and a high level signal is output from the output 44 of the comparator 41. Since this high-level signal is applied to the gate electrode 33G, the n-channel MOSFET 33 is turned on, bypassing the parasitic diode 35 and passing through the MOSFE.
A current flows through the channel formed in T33.
Therefore, since the voltage drop due to the forward voltage Vf of the diode 35 disappears, the voltage V1 on the source side drops to near the voltage V2 on the drain side, and the loss due to the forward voltage Vf can be reduced. In this unidirectional unit 31 as well, since there is a voltage drop due to the channel formed in the MOSFET 33, the voltage V1 on the source side is kept higher than the voltage V2 on the drain side, and this potential difference is detected by the comparator 41 of this example, The MOSFET 33 is turned on while the current is flowing from the source 33S to the drain 33D.

Also in the unidirectional unit 31, the comparator 41 is provided with detection voltage hysteresis so that a forward current flows through the diode 35 and a forward voltage Vf is generated to cause the non-inverting input 43 and the inverting force 42 to have a certain level or more. A high level signal is output to the output 44 of the comparator 41 when the potential difference of 1 is generated, and the output 44 of the comparator 41 is the low level signal when a predetermined potential difference or a negative potential difference smaller than the constant level potential difference is generated. It is also possible to configure the comparator 41 to switch to. In this way, by giving a difference (hysteresis) to the detection voltage for turning on / off the MOSFET 33, M
The OSFET 33 can also be composed of a switch having a small channel voltage drop, and further, an ideal switch having no voltage drop at all, so that the rectification effect can be further improved.

The movement of the unidirectional unit 33 will be summarized with reference to the timing chart shown in FIG. Time t14
At time t15, the voltage (V1-V2) across the MOSFET 33 becomes positive, that is, the voltage Vc of the auxiliary capacitor 27 and the generated voltage. When the sum of V0 'becomes equal to or higher than the charging voltage Vsc of the large-capacity capacitor (in the absolute value because it is on the negative side), a current flows through the diode 35. Therefore, a forward voltage is generated across the MOSFET 33 and is detected by the comparator 41 at time t16. As a result, the MOSFET 33 is turned on, the voltage drop across the MOSFET 33 does not reach the forward voltage Vf, and the voltage drop due to the channel is suppressed. The large-capacity capacitor 5 is charged in such a situation that the voltage drop due to the unidirectional unit 33 is very small.

At time t17, when the generated voltage V0 'exceeds the peak and the sum of the voltage Vc of the auxiliary capacitor 27 and the charging voltage Vsc of the large-capacity capacitor 5 becomes less than or equal to the charging voltage Vsc (MOSFET3
Although it includes the voltage drop due to the 3 channels),
Since the charging voltage Vsc of the large capacity capacitor 5 becomes higher, discharging starts from the large capacity capacitor 5.

When discharge starts from the large-capacity capacitor 5,
As described above, since the voltage V1 on the source side 33S becomes lower than the voltage V2 on the drain side 33D, the comparator 4
The one output 44 is inverted to a low level. Therefore, the n-channel MOSFET 33 is turned off, and the reverse voltage is applied to the diode 35 as well, so that the discharge from the large-capacity capacitor 5 is blocked by the unidirectional unit 33.

When the phase of the AC power supplied from the power generator 1 changes and the generated voltage V0 becomes higher than the ground voltage Vdd, the auxiliary capacitor 27 is operated by the other one-way unit 30 described above. And are connected in parallel to each other, and the auxiliary capacitor 27 is charged. During this time, the unidirectional unit 31 does not flow a current when the voltage V2 on the drain side is smaller than the voltage V1 on the source side (the voltage V2 becomes higher than V1). Therefore, even if there is an input from the power generator 1, if the generated voltage V0 is smaller than the charging voltage Vsc of the large-capacity capacitor 5, no current flows and the electric charge charged in the large-capacity capacitor 5 is discharged. Protects. In addition, the MOSFET 3 of this example
2 and 33 adopt the enhancement type, and when no voltage is applied to the gates 32G and 33G, the MOSFETs 32 and 33 are turned off,
The functions of the diodes 34 and 35 are utilized. Even when the large-capacity capacitor 5 has no voltage and the control circuits 36 and 37 do not operate, the rectifier circuit 24 is constituted by the diodes 34 and 35,
The power of the power generator 1 can be rectified and supplied to the large-capacity capacitor 5 and the processing device 9.

Thus, the one-way unit 30 of this example
And 31 are capable of blocking the reverse current, and the forward voltage loss with respect to the forward current, the MOSFET 3
It is possible to reduce the loss due to the on resistances of 2 and 33. Therefore, the unidirectional unit 30 can charge the auxiliary capacitor 27 to a voltage close to the generated voltage V0, and the unidirectional unit 31 also adds the voltage charged in the auxiliary capacitor 27 as the rectified voltage to the generated voltage V0. A voltage close to twice the voltage can be supplied to the outputs 22 and 23. Therefore, the rectification efficiency ηc shown in the equation (2) can be significantly improved. On the other hand, when the current flows in the opposite direction of the unidirectional units 30 and 31, the MOSFETs 32 and 33 are turned off, so that the diodes 34 and 35 can prevent the reverse current. Therefore, the leakage loss can be reduced. By using a unidirectional unit, this leakage loss can be made to a level that is almost negligible, that is, a reverse leakage current of the MOSFET, that is, 1 nA or less, which is a level that can be neglected. It is very effective in a low-power system of several 100 nA. As described above, in the power supply device 20 in which the rectifying circuit 24 is configured by the unidirectional unit of the present invention, the generated power can be supplied to the output ends 22 and 23 so that the loss is hardly generated. Therefore, it is possible to provide a power supply device with high power supply efficiency and low loss, and to efficiently supply the electric energy obtained from the motion of the rotary weight to the processing circuit 9 such as the timing device to operate its function. You can In addition, the large-capacity capacitor 5 connected to the output end 22
To the large-capacity capacitor 5 to charge the power generation device 1
Even when the power cannot be generated, the processing device 9 can be continuously operated by the electric power of the large-capacity capacitor 5. As described above, according to the present invention, it is possible to provide a small electronic device suitable for carrying.

[Second Embodiment] FIG. 3 shows, as a different example of the present invention, an outline of an electronic device 10 capable of operating a processing device 9 such as a clock device by a solar cell 2 which is a DC power source. . The electronic device 10 includes a power supply device 20 that supplies the DC power from the solar cell 2 to the large-capacity capacitor 5 that is a charging device and the processing device 9.
The power supply device 20 includes a first output end 22 connected to the large-capacity capacitor 5 and a second output end 23 connected to the processing device 9. The second output 23 has a first
A resistor 28 for start-up is connected in series to the output terminal 22, that is, the large-capacity capacitor 5, and a bypass switch 51 is connected in parallel with the resistor 28.
Therefore, when the charge level of the large-capacity capacitor 5 is low, the large-capacity capacitor 5 is connected to the output terminal 23 connected to the processing device 9 by the start-up resistor 28 in order to prevent power from being mainly consumed. Sufficient voltage is generated. Further, when a certain amount of voltage is generated in the large capacity capacitor 5, the startup resistor 28 is bypassed by the bypass switch 51 so that the large capacity capacitor 5 can be charged efficiently.

An auxiliary capacitor 8 is connected in parallel to the processing device 9 of the present example in order to stabilize the operating voltage. In addition, the power supply device 20 is connected to the solar cell 2 in parallel with the short-circuiting switch 52, and the voltage V 0 generated by the solar cell 2 becomes too high, so that the processing device 9 and the large-capacity capacitor 5 are adversely affected. When it reaches, the input from the solar cell 2 is short-circuited so that the output voltage V1 does not become too high. In order to perform such control, the power supply device 20 is provided with a control circuit 37. The control circuit 37 monitors the generated voltage V0 and the output voltage V1 on the output terminal 23 side of the large-capacity capacitor 5 for short-circuiting. Switch 5
2 and the bypass switch 51 can be operated.

In this power supply device 20, when the output of the solar cell 2 for converting discontinuous light energy into electric power decreases, the electric power discharged from the large-capacity capacitor 5 is output to the output terminal 2.
2 is supplied to the output end 23 and the processing device 9 is driven. At this time, if a current flows from the large-capacity capacitor 5 to the solar cell 2, electric power is wasted and the solar cell 2 may be damaged. For this reason, the power supply device 20 is provided with a unidirectional unit 31 for preventing backflow from the large-capacity capacitor 5 to the solar cell 2.

The unidirectional unit 31 of this example is connected so that a current flows when the electromotive voltage V0 of the solar cell 2 is larger in absolute value than the voltage V1 of the output terminal 22 connected to the large capacity capacitor 5. And a switch 38 connected in parallel with the diode 35. The switch 38 is provided with a control signal φ from the control circuit 37.
It is designed to be operated by 1. FIG. 4 shows an example of the control signal φ1. The generated voltage V0 and the output voltage V1 of the output end 22 are introduced into the control circuit 37,
These voltages V0 and V1 correspond to the voltage across the diode 35. First, at time t1, when the solar cell 2 is not generating power and no electric charge is stored in the large-capacity capacitor 5, the generated voltage V0 and the output voltage V1 are 0, and the difference between them is also 0. Therefore, the control signal φ1 is held at the low level and the switch 38 is off. In order to turn off when the control power supply cannot be secured, for example, a field effect transistor switch such as an enhancement type MOSFET can be used.

Next, when the solar cell 2 starts to generate electricity at time t2, the generated voltage V0 increases (to the minus side). Therefore, a current flows through the diode 35 and a forward voltage Vf is generated. Therefore, the voltage V at the other end of the diode 35 is
1 becomes smaller than the generated voltage V0 on the plus side. The control circuit 37 detects the potential difference and detects the control signal φ1 at time t3.
Is set to a high level and the switch 38 is turned on. As a result,
Electric power from the solar cell 2 bypasses the diode 35 and flows, and the large-capacity capacitor 5 does not lose the forward voltage Vf.
And to the processing circuit 9.

When the bypass switch 38 is turned on, the diode 35 does not influence the forward voltage Vf.
There is almost no difference between the voltages V1 and V0. Of course, since there is a voltage drop due to the switch 38, the bypass switch 38 may be controlled by detecting this voltage drop as in the above example. In this example, the bypass switch 38 is once turned off at a time t4 when a predetermined time has passed since the bypass switch 38 was turned on. Bypass switch 38
When the diode is turned off, the forward voltage Vf generated by the diode 35
Is detected, the bypass switch 38 is again activated at time t5.
Turn on. Thus, the unidirectional unit 3 of this example
In No. 1, the bypass switch 38 is turned off periodically to sample the forward voltage Vf so that the direction of the current flowing through the diode 35 can be detected. Therefore, the forward voltage Vf of the diode 35 is periodically set.
Occurs between the solar cell 2 and the large-capacity capacitor 5, so that the charging efficiency is impaired. However, the influence of the forward voltage Vf can be removed while the switch 38 is on. Therefore, in the conventional voltage supply device, the loss of the forward voltage Vf is always generated, so that the power supply efficiency of the voltage supply device 20 can be significantly increased as compared with the loss.

When the solar cell 2 stops generating electricity at time t9, the difference between the voltages V1 and V0 is reversed, and the absolute value of the voltage V0 becomes smaller. As a result, the control signal φ1 goes low and the switch 38 is turned off. When the value obtained by subtracting V0 from the voltage V1 becomes negative, the diode 35 also goes in the reverse direction, so that no current flows. Therefore, a current does not flow through the unidirectional unit 31 of this example, the power does not flow backward from the large-capacity capacitor 5 to the solar cell 2 side, and the power of the large-capacity capacitor 5 is supplied to the processing device 9 via the output terminal 23. Is supplied,
The processing device 9 continues to operate.

As described above, also in the power supply device 20 of this embodiment, by using the unidirectional unit 31 of the present invention for blocking the reverse current, the loss due to the forward voltage Vf of the diode can be prevented and the power can be efficiently supplied. Can be transferred. Also,
Since the large-capacity capacitor 5 can eliminate the loss due to the forward voltage Vf when supplying the electric power to the processing device 9, it is possible to employ an element having a large forward voltage Vf and a small reverse leakage current and leakage. A silicon diode capable of reducing loss can be adopted as the backflow prevention element 35.

Further, in this example, the operation and effect of the resistor 28, the switch 51, the capacitor 8 and the switch 52 have been mainly described, but these configurations are applied to the above-described first embodiment and equivalent operation is performed. And of course, it is possible to obtain the effect. Furthermore, in this example, the direction of the current flowing through the diode is detected by periodically turning off the bypass switch 38 of the unidirectional unit 31, but the same applies to the MOSFETs 32 and 33 of the first embodiment. Is possible. By detecting the directions of the currents flowing in the diodes 34 and 35 by sampling in this way, it is possible to configure a rectifier circuit using an ideal MOSFET that does not cause a voltage drop due to the channel, and more efficiently. Power can be supplied. Further, since the operation of the comparator 41 may be sampling (discrete) by detecting the current direction or the voltage direction in a sampling manner, the power consumption of the control circuit can be reduced. Power supply efficiency can be improved.

As described above, the power supply apparatus according to the present invention can detect the forward voltage generated in the diode and turn on the switch for bypassing the diode to prevent the loss of the forward voltage. Therefore, it is possible to significantly reduce the loss in the rectifier circuit that rectifies the AC power and the loss in the backflow prevention element, and the power can be transferred from the input end to the output end without the loss due to the forward voltage. Further, in the unidirectional unit of the present invention, the switch is turned off when a voltage is applied in the reverse direction, and the diode can prevent the reverse current, so that the reverse current from the output end to the input end is also blocked as in the conventional case. Therefore, it is possible to prevent the power once stored in the large-capacity capacitor or the auxiliary capacitor of the processing device from being wasted.

Therefore, at the input end of the power supply device of the present invention, a power generation device for outputting direct current such as a solar cell or a thermoelectric element, or a power generation device for outputting alternating current using an electromagnetic generator or a vibration type thermoelectric element. By connecting,
It is possible to provide a power generation device with high power supply efficiency, which has no loss due to the forward voltage of the diode and has little leakage loss. Therefore, by the power generator of the present invention, the power from a solar cell or thermoelectric element having a small energy density, or a generator using a rotary weight that captures the movement of the user to generate power can be efficiently supplied to the processing device and the charging device. Can supply,
A power generator suitable for carrying can be provided. Further, the unidirectional unit of the present invention is a very simple and miniaturizable unit such as a combination of a diode and a switch, or a field effect transistor switch such as MOSFET and its parasitic diode. Suitable for equipment. In addition, by mounting the power supply device or the power generation device of the present invention together with a processing device having a timekeeping function, it is possible to provide a portable and self-powered electronic device, and to charge a large-capacity capacitor or the like. By using the device together, it is possible to provide an electronic device capable of continuously operating the processing device for a long time under various environments. The electronic device of the present invention can be realized as a wristwatch or other portable type, or a vehicle-mounted type, and is not limited to the electronic device having the clock function described in the above example, but a pager. , A telephone, a wireless device, a hearing aid, a pedometer (registered trademark), an information terminal such as a calculator, an electronic notebook, an IC card, a radio receiver, and the like can be incorporated with various processing devices which operate by consuming power. Of course.

Of course, the present invention is not limited to the circuit examples of the electronic devices 10 described above. For example,
The unidirectional unit for backflow prevention shown in FIG. 3 can be used as the unidirectional unit of the rectifier circuit of the AC power supply shown in FIG. 1 and vice versa. Further, the rectifier circuit may be a circuit for performing full-wave rectification by combining a unidirectional unit in a bridge type or a circuit for performing half-wave rectification using the unidirectional unit, in addition to the boost rectifier circuit described above. Of course good things. Also, in boost rectification, not only the above-mentioned double boosting but also a boosting circuit of triple or more can be used. Further, as the switch for bypassing the diode, a bipolar transistor switch can be used in addition to the unipolar transistor such as a field effect transistor, and the power supply device can be provided as an IC or provided on the same semiconductor substrate together with the processing device. Various variations are possible.

[Third Embodiment] FIG. 5 shows a power generator 1
An example of a power supply device 20 capable of full-wave rectifying the AC power from the device using the unidirectional unit 30 and supplying the AC power to the processing device 9 and the charging device 5 is shown. As described above, it is possible to assemble four unidirectional units into a bridge for full-wave rectification, but in the power supply device 20 of this example, the unidirectional unit 30a including the comparator 41 is used.
And 30b and the MOSFETs 60a and 60b constitute a bridge for full-wave rectification. Therefore, in the rectifier circuit 24 of this example, the number of the one-way units 30 is two, and the two comparators 41 may be provided. Therefore, the circuit is simplified, and the semiconductor device (ASIC) in which the rectifier circuit 24 is mounted is installed. Power supply device 20 that can be made compact and can be easily installed in a portable electronic device at a lower cost
Can be realized.

In the rectifier circuit 24 of this example, the input terminal A connected to the power generator 1 in order to form a bridge.
Two unidirectional units 30a and 30b are connected in parallel between G1 and AG2 and one output terminal O1 connected to the charging device 5 and the processing device 9, and the input terminals AG1 and AG2 and the other one Rectification MOSFETs 60a and 60b are connected in parallel with the output terminal O2. The unidirectional units 30a and 30b are
A p-channel type MOSFET 32 and a control comparator 41 are provided respectively, and their detailed configurations are the same as those of the above-mentioned one-way unit, and therefore description thereof will be omitted below. On the other hand, the MOSFETs 60a and 60b connected in parallel with the output terminal O2 are
It is an n-channel type, the drain side 60D is connected to the input terminals AG1 and AG2 on the power generator side, and the source side 60S is connected to the output terminal O2. further,
The gate terminal 60G of the MOSFET 60a is an input terminal AG
2 is connected to the gate terminal 60G of the MOSFET 60b
Is connected to the input terminal AG1. Furthermore, MOSF
The gate side 60G of the ETs 60a and 60b is connected to respective input terminals AG2 and AG1 via a drive element including an inverter 61, a MOSFET 62 for driving the inverter 61, and a pull-up resistor 63. These drive elements are driven by the voltages of the power generator side AG1 and AG2, and further rectification MOSFETs 60a and 60 are used.
b can be controlled so that MOSFETs 60a and 60b
It is possible to adjust the on / off timing without affecting the. That is, by arbitrarily changing the threshold value of the driving element MOSFET 62, the rectification MOSFET 60
The timing at which a and 60b move can be arbitrarily selected. The voltage on the side of the power generator may be directly supplied to the gate side 60G of the rectifying MOSFETs 60a and 60b, but if the threshold value is changed to adjust the timing, the drive capability is reduced or the leak current is increased. Poor performance. On the other hand, when the driving element is provided, the timing can be adjusted without affecting the performance of the MOSFETs 60a and 60b.

The operation of the rectifier circuit 24 of the power supply apparatus 20 of this example will be described based on the timing chart shown in FIG. Power generation is started in the power generator 1, the potential of the input terminal AG1 rises from the low potential Vsc to the high potential Vdd,
When the threshold value of the driving element MOSFET 62 is reached at time t21, the MOSFET 62 is turned on. Therefore, the output of the inverter 61 changes from the low potential to the high potential, and the rectifying MOSFET 60b is turned on. Furthermore, input terminal AG1
When the voltage rises and becomes equal to or higher than the charging voltage Vdd of the charging device 5, a forward voltage is generated in the unidirectional unit 30a. As a result, at time t22, M of the unidirectional unit 30a is
When the voltage across the OSFET 32 reaches a predetermined value, the output of the comparator 41 changes to a low potential and the MOSFET 32
Turns on, and the unidirectional unit 30a conducts without loss due to the forward voltage. Therefore, the electric power from the power generation device 1 is supplied to the charging device 5 or the processing device 9. Generator 1
When the electromotive voltage starts to reverse, the voltage across the MOSFET 32 of the unidirectional unit 30a decreases at time t23, the output of the comparator 41 changes to high level, and MO
The SFET 32 turns off. Further, when the voltage of the input terminal AG1 decreases, it becomes less than or equal to the threshold of the MOSFET 62 that is a driving element, and at time t24, the rectifying MOSFET 60
b also turns off. Therefore, the reverse direction current does not flow due to the parasitic diode 34 of the unidirectional unit 30a and the parasitic diode 65 of the MOSFET 60b.

The same applies when the electromotive voltage of the power generator 1 is reversed, and the voltage of the input terminal AG2 rises, the rectifying MOSFET 60a is turned on at time t25, and time t26.
Then, the unidirectional unit 30b conducts without loss of forward voltage. Therefore, electric power is supplied from the power generation device 1 to the charging device 5 and the processing device 9 with high efficiency. On the other hand, the input terminal AG
The voltage of 2 drops and at time t27, the unidirectional unit 30
b is turned off, and at time t28, the rectifying MOSFET 6
0a turns off. Thereby, the unidirectional unit 30
The current in the opposite direction does not flow through b and MOSFET 60a. In this way, the full-wave rectification is performed, and even when the full-wave rectification is performed using the bridge of this example, the unidirectional unit 30a
And 30b, and MOSFETs 60a and 60b
It is possible to prevent the loss due to the forward voltage of the diode at the time of conduction. Power generator 1 that can be stored in a portable electronic device
Since the electromotive voltage is less than the forward voltage of the silicon diode to several times higher, the rectification efficiency is very high and the power supply efficiency is high by removing the loss due to the forward voltage of the silicon diode as in the above embodiment. A power supply device can be provided.

In place of the pull-up resistor 63, a suitable constant current generating circuit is used for the high voltage side Vdd and N channel MO.
It may be connected to the drain side of the SFET 62. Further, the N-channel MOSFET 62 is off in the steady state during non-power generation, and no current flows through the resistor 63 and the MOSFET 62. This is the same even when the constant current generating circuit is used. Further, instead of the driving elements of the N-channel MOSFET 62 and the pull-up resistor 63, a CMOS inverter circuit composed of an N-channel MOSFET and a P-channel MOSFET may be used. Even in this case, it is off in the stable state during non-power generation, and no current flows. Furthermore, the input terminal AG
1 and power supply voltage Vsc, and input terminal AG2 and power supply voltage Vsc
It is also possible to stabilize the potentials of the input terminals AG1 and AG2 in a steady state during non-power generation by inserting a pull-down resistor between and.

In FIG. 7, unidirectional units 30a and 3 are shown.
0b and a different example of the power supply device 20 including the rectifying circuit 24 that performs full-wave rectification using the rectifying MOSFETs 60a and 60b. Wristwatch device 10 of this example
Is a booster circuit 70 capable of boosting the voltage Vsc discharged from the capacitor 5 and operating the processing device 9 as the power supply voltage Vss.
Is equipped with. Such a booster circuit 70 can be realized by using a circuit capable of boosting two, three, or more stages by switching a plurality of capacitors. Of course, the booster circuit 70 can also supply the voltage Vsc of the capacitor 5 as the power supply voltage Vss without boosting it.

Further, the power supply device 20 of this example is provided with a power supply terminal 29 for receiving the supply of the power supply voltage Vss which can be boosted by the booster circuit 70, and the power supply voltage Vss is one-way units 30a and 30b. MOSFET 6 for rectification
It is designed to be used as an operating power supply for the control circuits 0a and 60b, that is, the comparator 41 and the inverter 61. Therefore, even when the capacitor (large-capacity capacitor) 5 is being charged, or even when the capacitor 5 is discharged and the voltage Vsc is decreasing, the unidirectional unit 30 is generated by the power supply voltage Vss obtained by boosting the voltage Vsc several times.
a and 30b, rectification MOSFETs 60a and 6
0b can be controlled. Therefore, even when the voltage Vsc of the capacitor 5 is low at the initial stage of charging or the final stage of discharging, a sufficient voltage can be secured to drive these MOSFETs forming the switch, so that the switching operation can be surely performed at high speed. It is possible to rectify efficiently. Therefore, the rectification loss at the initial stage of charging or the final stage of discharging can be reduced. For example, high potential Vdd
On the other hand, when the voltage Vsc is as small as about -0.5V, for example, a power supply voltage Vss of about -1.5V boosted three times can be secured, and the P-channel of the unidirectional unit 30a is secured by this power supply voltage Vss. The MOSFET 32 can be driven. Since the drive capability of the P-channel MOSFET increases with the square of the gate voltage, it is possible to achieve almost 9 times the drive capability by controlling with the boosted power and to perform rectification efficiently.

FIG. 8 shows an example of a power supply device 20 different from the above. The power supply device 20 of this example is
N on the low potential side (Vsc side) of the rectifier circuit 24 that performs full-wave rectification
The unidirectional units 31a and 31b using the channel MOSFET 33 are connected, and a P-channel type MOSFE as a rectifying MOSFET on the high potential side (Vdd side).
T80a and T80b are connected. And MO
The gate terminal 80G of the SFET 80a is operated by the voltage of the input terminal AG2, and the gate terminal of the MOSFET 80b is operated by the voltage of the input terminal AG1 on the opposite side. The gate side 80G of the MOSFETs 80a and 80b includes an inverter 81 and an MO for driving the inverter 81.
A driving element including an SFET 82 and a pull-down resistor 83 is provided. Further, a receiving terminal 29 for receiving the power supply voltage Vss is provided, and at the power supply voltage Vss, the unidirectional units 31a and 31b and the rectifying MOSFET.
It is possible to control 80a and 80b. The operation of these drive elements is similar to that of the circuit described above with reference to FIG. 7 in consideration of the difference in polarity, and therefore detailed description thereof is omitted here.

As described above, it is possible to configure the power supply circuit 20 by inverting the polarities of the MOSFETs forming the unidirectional unit and the switch. Further, in this example, since the unidirectional units 31a and 31b using N-channel MOSFETs having a larger drive capacity than the P-channel MOSFETs are adopted, the output of the comparator 41 for controlling the unidirectional units is changed to the N-channel MOSFETs. It can be made smaller. Therefore, the area occupied on the chip can be reduced in order to realize the unidirectional unit for achieving the same drive capability, and the power consumption can be reduced as compared with the above.

[Fourth Embodiment] FIG. 9 shows unidirectional units 30a and 30b and a rectifying MOSFET 6.
Rectifier circuit 24 for full-wave rectification using 0a and 60b
A different example of the power supply device 20 having the is shown.
In this example, unidirectional units 30a and 30b
Each has an OR circuit 48 as a control unit of the p-channel type MOSFET 32, and further has a three-input comparator 47 as a common control unit of the unidirectional units 30a and 30b.

The non-inverting input 47a of the comparator 47, which is common to the two unidirectional units, is connected to the high potential Vdd, and the two inverting inputs 47b and 47c are respectively connected to the input terminals AG1 and AG2 connected to the generator 1. It is connected. Therefore, as for the output of the comparator 47, the potential of either one of the input terminals AG1 and AG2 is the high potential Vdd.
The higher the potential, the higher the potential changes to the lower potential. And
In each of the unidirectional units 30a and 30b, the input signal of the inverter 61 for driving the corresponding rectifying MOSFETs 60b and 60a and the 3-input comparator 4 are provided.
The output signal of No. 7 is input to the OR circuit 48, and when both signals become low potential, the p-channel MOSFET 32 is turned on so that power can be supplied without loss due to the forward voltage of the diode. By thus sharing the comparators that control the unidirectional units 30a and 30b, the total number of comparators can be reduced, so that the semiconductor device (ASIC) that constitutes the power supply device 20 can be made compact and portable. It is possible to facilitate the storage in a mold type electronic device and reduce the manufacturing cost. Furthermore, since the number of comparators can be reduced, the power consumed by the comparators can also be reduced. Comparator 1
Since the power consumption per group is about 50 nA, by reducing the number of comparators from two to one in this example,
It is possible to improve the power consumption by about 0 nA. As explained earlier, power consumption like a wristwatch is several hundreds.
In a low power system of about nA, the effect of reducing the power consumption by reducing the number of comparators is very large.

Since the other configurations are common to those of the power supply device 20 described with reference to FIG. 5, description thereof will be omitted.

The operation of the rectifier circuit 24 of the power supply device 20 of this example will be described based on the timing chart shown in FIG. When power generation is started in the power generator 1, the potential of the input terminal AG1 rises from the low potential Vsc to the high potential Vdd and reaches the threshold of the MOSFET 62 of the driving element at time t31, the MOSFET 62 turns on. Therefore, the input side of the inverter 61 changes from a high potential to a low potential, and the output side changes from a low potential to a high potential, and the rectifying MOSFET 60
b turns on. Furthermore, the voltage of the input terminal AG1 rises,
When the charging voltage of the charging device 5 becomes equal to or higher than Vdd, a forward voltage is generated in the unidirectional unit 30a. Therefore, time t32
Since the output of the 3-input comparator 47 has a low potential and both signals input to the OR circuit 48 of the unidirectional unit 30a have a low potential, the p-channel MOSFE
T32 turns on. Thereby, the unidirectional unit 30
a conducts without loss due to the forward voltage of the diode, and the power from the power generation device 1 is supplied to the charging device 5 or the processing device 9. When the electromotive voltage of the power generator 1 starts to reverse, at time t33, the MOSFET 32 of the unidirectional unit 30a
The voltage across both ends of the MOSFET decreases, the output of the common comparator 47 changes to high level, and the MOSFET 32 turns off. Further, when the voltage of the input terminal AG1 decreases, the voltage becomes less than or equal to the threshold value of the MOSFET 62, which is a driving element, and the rectifying MOSFET 60b also turns off at time t34. Therefore, 1
Parasitic diode 34 and MO of directional unit 30a
The parasitic diode 65 of the SFET 60b prevents current from flowing in the opposite direction.

When the electromotive voltage of the power generator 1 is inverted, the voltage of the input terminal AG2 rises and the rectifying MOS is generated at time t35.
The FET 60a is turned on. At time t36, the output of the common 3-input comparator 47 becomes low potential, and the MOSFET
Since the input voltage of the inverter 61 on the side of 60a has a low potential, the output of the OR circuit 38 of the unidirectional unit 30b has a low potential and the MOSFET 32 is turned on. Therefore, the unidirectional unit 30b and the MOSFET 6
0a conducts without loss of forward voltage, and power is supplied from the power generation device 1 to the charging device 5 and the processing device 9 with high efficiency. When the voltage of the input terminal AG2 drops, 1 at time t37
Directional unit 30b is turned off, and at time t3
8, the rectifying MOSFET 60a is turned off. Thereby, the unidirectional unit 30b and the MOSFET 60
The reverse current does not flow in a. In this way, full-wave rectification is performed, and power is supplied with almost no loss of forward voltage due to the diode.

In a wrist-worn electronic device using a rotary weight for the power generator 1, a power supply device having a rectifying circuit using the unidirectional unit as described above, and a Schottky diode having a Vf smaller than that of a silicon diode. A comparison has been made of the amount of electric charge charged in a power supply device that has a rectifier circuit using the. As a result, in the power supply device employing the one-way unit, the movement of the rotary weight is larger, that is, the movement of the rotary weight is 1.32 times when the rotary weight is vertically set and turned 180 degrees. Is small, that is, 1.71 when the rotary weight is raised to 30 degrees and rotated 90 degrees.
Double the amount of charge is obtained. From this result, it is found that the rectification efficiency is significantly improved by adopting the unidirectional unit, and further, when the electromotive voltage is small,
That is, it can be seen that the smaller the movement of the rotary weight, the higher the improvement rate of the rectification efficiency. Therefore, in the portable electronic device that employs the power supply device using the unidirectional unit of this example, power can be efficiently supplied even with a small movement of the arm, and a portable electronic device with high charging capability can be provided.

In the above example, the unidirectional unit is composed of a p-channel type MOSFET and a rectifying MOS is formed.
Although the FET is an n-channel type, it is of course possible to configure the power supply device by using a conductivity type different from these.

As described above, according to the present invention, the rectification function or the backflow prevention function is realized by using the unidirectional unit in the power supply device having the power generator which can be housed in the portable electronic equipment. , Has realized a power supply device with high power supply efficiency. In particular, the electromotive force of the power generator that can be housed in the portable electronic device is close to the forward voltage of the diode, and since the electromotive force fluctuates, it is possible to supply the power by removing the loss due to the forward voltage of the diode.
The charging ability of the portable electronic device can be dramatically improved. Therefore, the power supply device adopting the one-way unit of the present invention uses a rotary weight or the like to detect the movement of the solar cell or thermoelectric element whose power generation capacity greatly varies depending on environmental conditions, or electromagnetic power for AC power generation. The power supply capacity of a power generator using a generator or thermoelectric element can be significantly improved, and the charging device of a portable electronic device can be charged.
In addition, sufficient power can be supplied to operate the processing device. Therefore, according to the present invention, it is possible to provide a portable electronic device that can continuously operate the processing device under various environments, regardless of the presence or absence of a battery, etc.
It is possible to provide an electronic device that allows the functions of the processing device to be fully exerted at any time and anywhere.

The power supply device of the present invention is suitable for portable electronic equipment, and is worn on a body such as an arm-mounted type,
By capturing such movements and the like, electric power is automatically generated, and the electronic device can be operated without using the battery or as an auxiliary power source of the battery.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a power supply device and an electronic device according to the present invention which employs a unidirectional unit.

FIG. 2 is a timing chart for explaining the operation of the rectifier circuit shown in FIG.

FIG. 3 is a block diagram showing an outline of a power supply device and an electronic device according to the present invention, which are different from the above and include a unidirectional unit.

4 is a timing chart showing a control signal for operating a switch of the unidirectional unit shown in FIG.

FIG. 5 is a block diagram schematically showing a power supply device and an electronic device that perform full-wave rectification using a unidirectional unit.

6 is a timing chart showing an operation of the power supply device shown in FIG.

FIG. 7 is a block diagram showing a different example of a power supply device and an electronic device that perform full-wave rectification using a unidirectional unit.

FIG. 8 is a block diagram showing different examples of a power supply device and an electronic device that perform full-wave rectification using a unidirectional unit.

FIG. 9 is a block diagram showing still another example of a power supply device and an electronic device that perform full-wave rectification using a unidirectional unit.

10 is a timing chart showing an operation of the power supply device shown in FIG.

FIG. 11 is a block diagram showing an example of a conventional electronic device.

FIG. 12 is a graph showing the characteristics of the forward voltage of a diode.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Osamu Shinkawa             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Tadao Kadowaki             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F-term (reference) 2F002 AA00 AB04 AE01 GA04                 2F084 AA00 GG02 GG04 GG08 JJ07                 5H006 AA06 BB08 CA02 CA07 CB04                       CB07 DC05

Claims (2)

[Claims] 1. A power supply device that can be incorporated in a portable electronic device, the power generation device generating DC power, and the power from the power generation device being charged or processed through at least one unidirectional unit. A supply unit for supplying the device, wherein the unidirectional unit turns on the bypass switch when a forward voltage is generated in the diode, a bypass switch connected in parallel with the diode, and the diode. And a control unit, wherein the supply unit uses the unidirectional unit to prevent backflow from a charging device or a processing device to the power generation device. 2. The power supply device according to claim 1, a charging device capable of accumulating direct-current power supplied from the power supply device, and a processing device operated by the direct-current power supplied from the power supply device. A portable electronic device comprising: