JPH08308100A - Electronic apparatus - Google Patents

Abstract

PURPOSE: To realize efficient power feeding from an external battery case by displaying the remaining capacity of a battery based on the difference between preset reference voltage and power supply voltage. CONSTITUTION: A power supply voltage detecting circuit 14 is connected with a battery remaining capacity displaying section 16. On the basis of the difference between the preset reference voltage and power supply voltage detected by the power supply voltage detecting circuit 14, the remaining capacity of a battery 13 is displayed on the battery remaining capacity display section 16. Namely, when there is no difference between the preset reference voltage and detected power supply voltage, no-remaining capacity of battery 13 is displayed. When the detected power supply voltage is higher than the preset reference voltage, the remaining capacity of battery 13 is judged as the difference increases and a judgment result is displayed. Thereby, power feeding from an external battery case 30 can be executed efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device that can be driven by a battery, and more particularly to an electronic device that is suitable for application to an electronic device that can both be driven by a battery and driven by a power source obtained from an external power source input terminal.

[0002]

2. Description of the Related Art Conventionally, there are various types of portable electronic devices that can use a battery as a power source.
In this case, in addition to being able to incorporate a battery, DC
There are many devices provided with an external power supply input terminal called a jack or the like so that the power supplied to this input terminal can also be used. For example, a converter (hereinafter referred to as an AC adapter) that converts a commercial AC power supply called an AC adapter into a DC low-voltage power supply is connected to the external power supply input terminal, and the device is driven by the power supply from this converter. Sometimes. Alternatively, the battery can be housed in a battery case prepared separately from the device body, and the battery case can be connected to an external power input terminal to supply power to the device from the battery in the battery case.

FIG. 3 is a diagram showing an example of the configuration of a power supply input section of a conventional electronic device having an external power supply input terminal. In the electronic device 1 shown in FIG. 3, the load circuit 2 is driven by the input jack 3
The external power source obtained in step 1 or the power source supplied from the battery 5 housed in the battery housing section 4 is used.

In this case, the input jack 3 includes a contact piece 3a which is a + side power source input terminal and a ground potential portion (G) of the load circuit 2.
ND), and a contact piece 3c that contacts the contact piece 3b when the plug is not inserted in the jack 3 and separates from the contact piece 3b when the plug is inserted. In this case, when a plug (not shown) such as an AC adapter is inserted into this jack 3, the contact on the + side of this plug contacts the contact piece 3a, and the contact on the ground side of the plug contacts the contact piece 3b. .

The contact piece 3a, which is the + side power supply input terminal of the input jack 3, is connected to the + side power supply input section of the load circuit 2 via the diode Da, and a reverse polarity current is applied to the load circuit 2 side. It is prevented from being supplied to.

The positive side of the battery 5 housed in the battery housing 4 is connected to the + side power source input part of the load circuit 2, and the negative side of the battery 5 is the contact piece 3c of the input jack 3. Connected to.

By configuring the power supply input section in this way, when the battery 5 is stored in the battery storage section 4 without inserting a plug such as an AC adapter into the input jack 3, the negative side of the battery 5 becomes , Input jack 3 contact piece 3
connected to the ground potential part of the load circuit 2 via c and 3b,
Power is supplied to the load circuit 2 from the battery 5, and the load circuit 2 can be driven.

When an AC adapter plug (not shown) is inserted in the input jack 3, the contact piece 3b of the input jack 3 is separated from the contact piece 3c by the insertion of the plug, and the negative side of the battery 5 is loaded. It is disconnected from the circuit 2 and the power supply from the battery 5 is cut off. The power supplied from the AC adapter to the input jack 3 is the diode D
It is supplied to the load circuit 2 side via a, and the load circuit 2 is driven by this power supply.

A power supply voltage detection circuit 6 is connected to the power supply input section of the load circuit 2, and the power supply voltage detection circuit 6 detects the power supply voltage from the power supply source connected to the battery 5 or the input jack 3. Is done. Then, when the detected voltage becomes lower than the minimum voltage at which the load circuit 2 can be driven by the battery 5, a command to stop the operation of the circuit in the load circuit 2 is sent to stop the operation of the load circuit 2. . The presence of the power supply voltage detection circuit 6 automatically stops the operation of the load circuit 2 when the output of the built-in battery 5 is lowered and the load circuit 2 cannot be driven.

[0010]

By the way, the power obtained from the outside to the input jack 3 is supplied to the load circuit 2 through the diode Da. Therefore, when the external power supply means such as an AC adapter is connected, this Diode D
The power supply having the potential lowered by the voltage drop value in the forward direction of a is supplied to the load circuit 2. Here, when an AC adapter is connected to the input jack 3, the commercial AC power is converted to a DC low-voltage power, so that a relatively stable potential power is supplied. There is no problem even if there is some voltage loss.

On the other hand, when the external battery case is connected to the input jack 3, the potential of the power source supplied from the battery in the external battery case becomes lower by the amount of the voltage loss at the diode Da and the load is reduced. The efficiency of driving the circuit 2 is reduced accordingly.

Here, the reason for using the external battery case will be described. For example, a battery having a larger capacity than the battery that can be installed in the battery housing portion 4 of the apparatus 1 can be installed in the external battery case so that the battery can be used for a long time. Used to allow continuous drive in time. Alternatively, there is a case where a battery having a different shape from the battery 5 (dry battery or a secondary battery having the same shape as the dry battery) that can be mounted in the battery housing portion 4 in the device 1 is used by being mounted in an external battery case. .

When power is supplied from the battery in the external battery case through the input jack 3, the voltage value detected by the power supply voltage detection circuit 6 becomes
The potential becomes lower than the original battery voltage by the voltage loss in the diode Da. Therefore, when the potential detected by the power supply voltage detection circuit 6 is lower than the minimum voltage at which the load circuit 2 can be driven by the battery 5 while the power is being supplied from the battery in the external battery case, The actual terminal voltage of the battery is a potential higher by the amount of voltage loss in the diode Da, and although the current that can drive the load circuit 2 is still supplied from the external battery case, the power supply voltage detection circuit 6 The operation of the load circuit 2 is stopped when it is determined that the connected battery has run out. Therefore, when the external battery case is used, the battery is not effectively utilized.

In order to solve this inconvenience, in an electronic device such as a conventional portable tape reproducing device, a terminal for connecting an external battery case is provided separately from the input jack 3 to which an AC adapter or the like is connected, The external battery case connection terminal is directly connected to the power supply input section of the load circuit 2 without the diode Da.

However, if the dedicated terminal for connecting the external battery case is provided in this way, there is a problem that the structure of the apparatus becomes complicated accordingly.

In view of the above points, the present invention has a simple structure.
The purpose is to enable efficient power supply from the external battery case.

[0017]

In order to solve this problem, the present invention provides a detection means for detecting the type of a power supply connected to a power supply input terminal and a reference voltage value depending on the detection state of the detection means. And a power supply voltage monitoring means for changing.

[0018]

According to the present invention, the reference voltage value to be compared with the power supply voltage monitored by the power supply voltage monitoring means changes according to the type of the power supply to be connected. Monitoring is possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In this example, a power input section is constructed as shown in FIG. That is, in the electronic device 10 shown in FIG. 1, as the power supply source of the load circuit 11, the battery 13 in the battery housing 12 or the external power supply source connected to the input jack 20 can be selected. Here, as the external power supply source, a DC low-voltage power supply from a battery in the external battery case 30 or a DC low-voltage power supply obtained by converting a commercial AC power supply by the AC adapter 40 is used.

The battery accommodating portion 12 of this embodiment has a shape capable of accommodating three dry batteries 13 (or secondary batteries having the same shape as the dry batteries) in series, and the positive electrode side of the accommodated batteries 13 is a load. The negative side of the battery 13 is connected to the + side power input of the circuit 2, and the contact piece 23 of the input jack 20 is connected to the negative side.
Connected to.

The input jack 20 includes a contact piece 21 which is a + side power source input terminal and a ground potential portion (G) of the load circuit 11.
ND), and a contact piece 23 that contacts the contact piece 22 when the plug is not inserted in the jack 20 and separates from the contact piece 22 when the plug is inserted. In this case, when the plug 42 or the like of the AC adapter 40 is inserted into the jack 20, the contact on the + side of the plug comes into contact with the contact piece 21, and the contact at the ground potential of the plug comes into contact with the contact piece 22.

Then, the contact piece 21 which is the + side power source input terminal of the input jack 20 is connected to the + side power source input portion of the load circuit 11 via the diode D1. Further, the ground potential part of the load circuit 11 and the negative electrode side of the battery 13 mounted in the battery housing part 12 are connected via the diode D2. The diodes D1 and D2 have a forward voltage drop of 0.4V.

Then, the power supply voltage detection circuit 14 detects the potential between the + side power supply input portion of the load circuit 11 and the ground potential portion. In this case, in the power supply voltage detection circuit 14 of the present example, the negative side of the power supply obtained at the battery 13 or the input jack 20 is supplied to the detection circuit 14 via the switch 15. The switch 15 is in a connected state when the operation portion is pushed by a protrusion 32 of the external battery case 30 described later, and is in a disconnected state in other states.

Then, the switch 15 is brought into the connected state, and the potential (ground potential) on the negative side of the power supply is detected.
Is supplied to the voltage detection circuit 14, the potential between the + side power supply input section of the load circuit 11 and the ground potential section detected by the voltage detection circuit 14 becomes
It is determined whether or not it is equal to or higher than the first potential Vth1. Then, the switch 15 is brought into the non-connection state, and the ground potential becomes the detection circuit 14
When the voltage is not supplied to the second potential Vth2, it is determined whether the potential between the + side power source input portion of the load circuit 11 and the ground potential portion detected by the voltage detection circuit 14 is the second potential Vth2 or more. Here, the first potential Vth1 is set to 2.2V and the second potential Vth2 is set to 2.6V.

In the power supply voltage detection circuit 14, the potential supplied to the load circuit 11 is the first potential Vth1 or the second potential Vth1.
When it is detected that the potential is lower than the potential Vth2, a command to stop the operation of the circuit in the load circuit 11 is sent to stop the operation of the load circuit 2.

A battery level indicator 16 is connected to the power supply voltage detection circuit 14, and the set reference potential (first potential Vth1 or second potential Vth2) and the detected potential are detected. The remaining battery level is displayed on the remaining battery level display unit 16 based on the difference between and. That is, when there is no difference between the set reference potential and the detected power supply voltage, it is displayed that the remaining battery level is low, and when the detected power supply voltage is higher, the higher the difference, the higher the difference. , Judge that there is a battery remaining, and display that fact.

Next, the external battery case 3 as a power supply source connected to the input jack 20 of the electronic device 10 of this example.
0 and the AC adapter 40, the external battery case 30 is designed so that batteries (not shown) such as dry batteries and secondary batteries can be stored in the case body, and the plug 31 is directly connected to the case body. By inserting the plug 31 into the input jack 20 of the electronic device 10, the external battery case 30 is integrated with the electronic device 10. In this case, the main body of the external battery case 30 is configured so as not to come off from the electronic device 10 by a connection mechanism (not shown). Furthermore, this external battery case 3
When 0 is connected to the electronic device 10, the protrusion 32 provided on the case body pushes the operating portion of the switch 15,
The switch 15 is connected.

The AC adapter 40 includes a converter main body 41 for converting a commercial AC power supply into a DC low-voltage power supply, and a plug 4 attached to the tip of a cord extending from the main body 41.
2 is inserted into the input jack 20 of the electronic device 10, and the AC plug 43 attached to the converter main body 41.
Is connected to an outlet (not shown) from which a commercial AC power supply is obtained, so that the DC low-voltage power supply is supplied to the electronic device 10 side. When this AC adapter 40 is connected,
The switch 15 remains unconnected.

Next, the load circuit 11 of the electronic device 10 of the present example.
The power supply state to the power supply will be described. First, when the battery 13 is mounted in the battery housing 12 in the device 10, the battery 1
The positive side of 3 is connected to the + side power input of the load circuit 2,
The negative side of the battery 13 has contacts 23, 2 of the input jack 20.
2 is connected to the ground potential portion of the load circuit 11 via 2, and power is supplied from the battery 13. Also, the contact pieces 22, 23
Even when is temporarily separated, the negative electrode side of the battery 13 is connected to the ground potential portion via the diode D2, and the power is stably supplied from the battery 13.

When the built-in battery 13 is used as a power supply source, the switch 15 is not connected and the power supply voltage detection circuit 14 supplies the power supply voltage from the battery 13 to the load circuit 11. Is the second potential Vth2
Judge whether it is (2.6V) or less. Here, when the remaining amount of the battery 13 is sufficient, it is determined that it is equal to or higher than the second potential Vth2, and the operation of the load circuit 11 is continued. Then, when it is detected that the power supply voltage supplied to the load circuit 11 becomes equal to or lower than the second potential Vth2 because the remaining amount of the battery 13 becomes small, the detection circuit 14 detects that the circuit in the load circuit 11 has the same voltage. Is sent to stop the operation of the load circuit 2.

When the plug 31 of the external battery case 30 is connected to the input jack 20 while the external battery case 30 is loaded with the remaining battery, the positive electrode of the battery in the battery case 30 is positive. Is connected to the + side power source input section of the load circuit 11 via the contact piece 21 of the input jack 20 and the diode D1, and the negative side of the battery in the battery case 30 is loaded via the contact piece 22 of the input jack 20. Circuit 1
It is connected to the ground potential part 1 and power is supplied from an external battery.

When the external battery case 30 is used as a power supply source, the protrusion 3 of the case 30 is used.
2 presses the operating portion of the switch 15 to bring the switch 15 into the connected state, so that in the power supply voltage detection circuit 14, the power supply voltage supplied from the external battery case 30 to the load circuit 11 is the first potential Vth1 (2. 2V) It is judged whether it is below. Here, when the remaining amount of the battery in the external battery case 30 is sufficient, it is determined that it is equal to or higher than the first potential Vth1, and the operation of the load circuit 11 is continued. Then, when it is detected that the power supply voltage supplied to the load circuit 11 becomes equal to or lower than the first potential Vth1 due to the low battery level, the detection circuit 14 detects that the circuit inside the load circuit 11 A command to stop the operation is sent to stop the operation of the load circuit 2.

Compared to the case of using the built-in battery 13, the voltage for stopping the operation of the load circuit 11 when the external battery case 30 is used is the second potential Vth2.
The first potential Vth1 is 0.4 V lower than (2.6 V)
Although it is (2.2V), the power from the external battery case 30 is supplied to the load circuit 11 via the diode D1. Since the diode D1 has a voltage drop of 0.4 V, when the internal battery 13 and the battery of the external battery case 30 have the same capacity, the internal battery 13
Is used as a power source, the detection circuit 14 detects the second potential Vth2, and the external battery case 30 is used as a power source.
When 1 is detected, the remaining battery levels are the same.

Therefore, by switching the voltage for stopping the operation of the load circuit 11 as in this example, it becomes possible to judge the remaining battery level under the same conditions when the internal battery is used and when the external battery is used. It is possible to always make a proper determination of the remaining amount of the battery and give an operation stop instruction based on the proper determination. Therefore, even when the external battery case 30 is used, the case 30
When the remaining battery level in the battery drops to such an extent that the load circuit 11 cannot be driven, the operation stops, and the battery in the case 30 can drive the load circuit 11 for a long time. Can be lengthened.

Since the jack 20 which is a terminal for connecting the external battery case 30 also serves as a terminal for connecting the plug 42 of the AC adapter 40, a dedicated terminal for the external battery case 30. Is unnecessary, and the structure of the device can be simplified accordingly.

Further, in the case of this example, when the built-in battery 13 and the external battery case 30 or the AC adapter 40 are connected at the same time, the diode OR gate circuit is formed by the diodes D1 and D2. This has the effect that the higher voltage power supply is automatically selected.

Further, in the case of this example, the display of the remaining amount of the battery can be performed under the same conditions for the internal battery and the external battery. That is, since the detection circuit 14 can determine the remaining battery level under the same conditions, the remaining battery level display on the display unit 16 is
Regardless of which battery is used, the same condition is used and accurate remaining amount can be displayed. In addition, since the remaining battery level display is accurate in this way, for example, when a rechargeable secondary battery is set in the external battery case and charged from a charging circuit (not shown) on the electronic device 10 side, The display unit 16 on the electronic device 10 side can display an accurate charging status, for example, it can accurately display that the charged amount is 100%.

The operation of the power supply voltage detection circuit 14 is shown in the flow chart of FIG. That is, it is determined whether the switch 15 is in the connected state (step 10
1) When in the connected state, the first potential Vth1 is set as the reference voltage (step 102), and when not in the connected state, the second potential Vth2 is set as the reference voltage (step 103).

In this state, it is judged whether the power supply voltage supplied to the load circuit 11 is equal to or lower than the reference voltage (step 10
4) If the voltage is equal to or lower than the reference voltage, a command to stop the operation is sent to the load circuit 11 (step 105).

When the plug 42 of the AC adapter 40 is connected to the jack 20 and the DC low voltage power supply obtained by converting the commercial AC power supply by this AC adapter 40 is used as the power supply, the switch 15 is not connected. Therefore, the reference potential in the power supply voltage detection circuit 14 is the second potential Vth.
2, the drop in the power supply voltage is detected in the same state as in the conventional case. However, the DC low-voltage power supply output from the AC adapter 40 is a power supply of stable current and voltage in a normal use state, and unless there is any abnormality, the power supply voltage detection circuit 1
4 does not detect a voltage drop.

In the above embodiment, the switch 15 is made up of mechanical contacts that are brought into a connected state when the operating portion is pressed. However, when the connection of the external battery case is detected by some means, the switch 15 is turned on. The switch may be configured by using an electric switching element or the like.

Further, in each of the above-described embodiments, the specific configuration of the load circuit in the electronic equipment is not shown, but various electronic equipment which can be driven by the DC low voltage power supply can be used as a load. .

[0044]

According to the present invention, the reference voltage value to be compared with the power supply voltage monitored by the power supply voltage monitoring means changes according to the type of the power supply to be connected. Allows voltage monitoring.

In this case, when it is detected that the power supply voltage monitored by the power supply voltage monitoring means is lower than the reference voltage value, a command for stopping the operation of the load circuit is output, so that the connection is established. Even if the type of power supply is different, it is possible to stop the operation of the load circuit under the same conditions.

Further, in this case, the power from the battery housed in the battery housing and the power supplied to the power input terminal are selectively supplied to the load circuit. Even when used, proper operation control is possible. be able to.

Further, in this case, the change amount of the voltage value in the power supply voltage monitoring means is set to the forward voltage drop value of the reverse polarity current blocking means, so that the control in the power supply voltage monitoring means is always the same condition. For example, when using the external battery connected to the power input terminal and when using the built-in battery, each battery can be used until it has an appropriate remaining amount, and the connected battery can be used as much as possible. Can be used for.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control state according to an embodiment.

FIG. 3 is a configuration diagram showing an example of a power supply input section of a conventional electronic device.

[Explanation of symbols]

 10 Electronic Equipment 11 Load Circuit 12 Battery Storage 13 Built-in Battery 14 Power Supply Voltage Detector 15 Switch 20 Input Jack 30 External Battery Case 40 AC Adapter D1, D2 Diode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H02J 9/06 503 H02J 9/06 503A 503C

Claims (4)

[Claims] 1. A power supply input terminal, a reverse polarity current blocking means connected in series with the power supply input terminal, a detection means for detecting the type of a power supply connected to the power supply input terminal, and a detection by the detection means. An electronic device comprising: a power supply voltage monitoring unit that changes a reference voltage value depending on a state. 2. The method according to claim 1, wherein when it is detected that the power supply voltage monitored by the power supply voltage monitoring means is lower than the reference voltage value, a command to stop the operation of the load circuit is output. Electronics. 3. A battery accommodating portion, wherein power supplied from a battery accommodated in the battery accommodating portion and power supplied to the power supply input terminal are selectively supplied to the load circuit. Item 2. The electronic device according to item 2. 4. The electronic apparatus according to claim 3, wherein the amount of change in the voltage value in the power supply voltage monitoring means is a forward voltage drop value of the reverse polarity current blocking means.