JPS63198546A - Electronic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device, particularly an electronic device having a rechargeable secondary battery, a solar cell for charging the secondary battery, and a charging circuit.

[Prior Art] Conventionally, devices using rechargeable batteries as secondary batteries have been known in small electronic devices such as tape recorders and calculators. This type of device usually has a built-in charging circuit,
Alternatively, the secondary battery can be charged and used using an external charging circuit. Possible power sources for the charging circuit include commercial power sources, car batteries, and the like.

In addition, in recent years, devices have become known that are equipped with a solar cell and charge a secondary battery with the solar cell during a period when there is sufficient incident light to the solar cell, allowing the device to operate even when there is insufficient incident light. ing.

Further, electronic devices that can use both a solar cell and a charging circuit using a power source such as the above-mentioned commercial power source are also being considered as means for charging a secondary battery.

[Problems to be Solved by the Invention] As described above, in a device in which both a solar cell and a charging circuit using a predetermined power source can be used to charge a secondary battery, the charging circuit is not in a usable state. When this happens, the charging circuit is prioritized as a power source for charging the secondary battery, so there is enough incident light on the solar cell and enough power to charge the secondary battery. Even when electricity is being generated, charging is performed using electricity from a commercial power source, which causes problems in that electricity is wasted and the electricity bill increases.

c. Means for Solving the Problems] In order to solve the above problems, the present invention provides a secondary battery, a solar cell for charging the secondary battery, and a charging system for charging the secondary battery using electric power from a predetermined power source. In an electronic device using the device, a means for detecting the output of the solar cell is provided, and when the detected value by the detection means is above a certain level, charging from the solar cell is given priority, and in other cases, charging from the solar cell is performed with priority. A configuration was adopted in which charging is performed using the charging device.

[Function] According to the above configuration, if the output of the solar cell is above a certain level, the solar cell is preferentially used as a charging means for the secondary battery, so energy resources are not wasted.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the structure of a power supply section of an electronic device adopting the present invention.

In the figure, the symbol l indicates a charging power source for charging the secondary battery indicated by the symbol B2. Here, power from a commercial power source (alternating current) la is transformed by a transformer lb, and further rectified by a rectifier 1c. A circuit for converting the current to direct current is shown. Rechargeable type [tl] is not limited to a commercial power source, and may be a power source such as a DC/DC converter using another DC power source such as a car battery.

The charging power source l is provided in the form of an AC adapter or the like that is externally attached to the device.

A solar cell SR can also be used to charge the secondary battery B2. The output of the solar cell SR is connected to a diode D to prevent backflow.
It is connected to the input of the charging control circuit 3 via. The output of the charging power supply 1 is connected to the input of a charging control circuit 3 via a current control circuit 2. Here, the current control circuit 2 is composed of an analog switch, etc., and the electric power of the charging power supply l is transferred to the charging control circuit 3 by the control of the voltage detection circuit 7, which will be described later.
This is to determine whether or not to supply the

The charging control circuit 3 is a circuit that charges the secondary battery B2 with a charging current suitable for the charging status of the secondary battery B2, and its operation is controlled by a charging voltage detection circuit 4, a temperature detection circuit 5, and a reference voltage detection circuit 6. be done.

Here, the charging voltage detection circuit 4 uses an operational amplifier or the like, and the difference voltage with respect to the reference voltage generation circuit 6 is detected by the charging control circuit 3.
It operates so that a charging current suitable for the state of charge indicated by the terminal voltage of the secondary battery is supplied to the secondary battery B2.

The reference voltage generating circuit 6 is similarly constructed using an operational amplifier or the like, and generates a reference voltage suitable for the ambient temperature detected by the temperature detecting circuit 5 made of a thermistor or the like.

In this embodiment, a voltage detection circuit 7 is provided to detect the output voltage of the solar cell SB. The voltage detection circuit 7 is a comparator configured using an operational amplifier or the like, and is connected to a predetermined reference voltage generated by a reference voltage generation circuit 8 configured using a Zener diode or the like and the solar cell SR.
The output voltage of the solar cell SB is compared, and when the output voltage of the solar cell SB is equal to or higher than a predetermined value, the current control circuit 2 operates to cut off the output of the charging power source 1.

The secondary battery B2 is constituted by a rechargeable battery such as a NiCd battery or a lead battery.

In the configuration described below, when the charging power source 1 is connected to the device, either the charging power source 1 or the solar cell SH can be used for charging.

Here, there is sufficient incident light on the solar cell SB, and the secondary battery B
When sufficient voltage is generated to charge the solar cell SR, the output voltage of the solar cell SR becomes higher than the reference voltage generated by the reference voltage generation circuit 8, and the current control circuit 2 is cut off.

When the charging power supply 1 is cut off by the current control circuit 2, the primary side output of the transformer ib of the charging power supply 1 becomes open, so almost no current flows through the primary side of the transformer ib, and the commercial power supply 1a Power consumption can be significantly reduced.

The power of the solar cell SH is given to the charging control circuit 3 via the diode D, and the secondary battery B2 is charged by the output of the solar cell SR.

At this time, a charging current corresponding to the terminal voltage of the secondary battery B2 detected by the charging voltage detection circuit 4 is applied to the secondary battery B2, and an appropriate charging current according to the charging state is applied.

At the same time, a reference voltage suitable for the ambient temperature detected by the temperature detection circuit 5 is generated by the reference voltage generation circuit 6,
Charging current is also controlled by ambient temperature. If the secondary battery B2 is a NiCd battery, the charging end voltage (
This is based on the charging characteristic that the higher the temperature, the higher the voltage value (voltage indicating the state of charge).

When the secondary battery B2 is sufficiently charged, the charging control circuit 3 takes appropriate measures such as switching the charging method to trickle charging, and controls the secondary battery B2 so that it does not become overcharged.

On the other hand, there is not enough incident light on solar cell SR, and secondary battery B
2 cannot be charged normally, the voltage detection circuit 7 is inverted and the current control circuit 2 becomes conductive. As a result, power is supplied to the charging control circuit 3 from the charging power source 1, and the secondary battery B2 is charged by the output of the charging power source 1. Charging current control at this time is performed using the charging control circuit 3, the voltage detection circuit 4, the temperature detection circuit 5, and the reference voltage generation circuit 6 in the same manner as described above. At this time, charging power supply l
The output of is blocked by diode D.

No voltage is applied to both ends of the solar cell SH.

As described above, according to this embodiment, when the solar cell generates a sufficient output voltage, the solar cell is used for charging with priority, so the power consumption of the charging power source l can be greatly reduced. It has a positive effect.

In the above embodiment, the output voltage of the solar cell SH is detected, and it is determined whether to connect the charging power source l via the current control circuit 2 based on the detected value. In addition to the voltage detection circuit, a current detection circuit 9 as shown in FIG. 2 may be used.

In FIG. 2, the current detection circuit 9 measures the output current by using a comparator or the like to detect the voltage drop across a detection resistor inserted into the power supply line of the solar cell SH, so that the output current of the solar cell SR is constant. If the value exceeds the current value, the current control circuit 2 cuts off the output of the charging power source 1.

The rest of the configuration is exactly the same as that in FIG. 1, and even with this configuration, when the output of the solar cell SH is sufficiently large, the charging power source can be cut off to reduce the power consumption of the charging power source I.

In the above, the power consumption of the charging power source 1 is reduced by changing the output of the charging power source 1 to el m. However, in a configuration where a transformer or the like is used as the charging Trl source as shown in the figure, even if the secondary side is cut off, a small
Current flows to the next side. Therefore, detect the output of the solar cell,
A configuration may be adopted in which the primary side of the transformer is controlled based on this, however, in this case, means such as a power transistor or a relay for controlling the power source of the charging power source 1 is required.

The above configuration can be applied to any electronic device that uses a secondary battery, a charging circuit for charging the secondary battery, and a solar cell.

[Effects of the Invention] As is clear from the above description, according to the present invention, a secondary battery, a solar cell for charging the secondary battery, and a charging device for charging using power from a predetermined power source are used. In the electronic device, means for detecting the output of the solar cell is provided, and when the detected value by the detection means is above a certain level, charging from the solar cell is given priority, and in other cases, the charging device Since a configuration is adopted in which charging is performed using It has the excellent effect of significantly reducing

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a power supply section of an electronic device adopting the present invention, and FIG. 2 is a block diagram showing a modification of FIG. 1. l...Charging power supply 2...Current control circuit 3...
・Charging control circuit 4...Charging voltage detection circuit 5...
Temperature detection circuit 6.8...Reference voltage generation circuit SR...Solar cell B2...Secondary battery D...
diode

Claims (1)

[Claims] In an electronic device that uses a secondary battery, a solar cell that charges the secondary battery, and a charging device that charges the secondary battery using electric power from a predetermined power source, means for detecting the output of the solar cell is provided, and An electronic device characterized in that when a detected value is above a certain level, charging from the solar cell is given priority, and in other cases, charging is performed by the charging device.