JP2914280B2 - Battery-operated electronic device and method of protecting electronic device when battery capacity is low - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery-driven electronic device having a protection device when the battery capacity is low, and more particularly to a portable battery-driven electronic device.

[0002]

2. Description of the Related Art Electronic devices have been miniaturized in response to miniaturization and higher density of electronic components, and portable electronic devices have been rapidly increasing as seen in recent personal computers, word processors and mobile terminals. In addition, with the reduction in power consumption of electronic components, it has become possible to operate for a long time using a battery power supply, and electronic devices that use a battery as a power source, mainly for portable devices, are increasing.

[0003] The output voltage of a battery of a power supply decreases with use, and if the output voltage falls below a certain limit, malfunction or destruction of memory contents may occur in electronic equipment. When a battery voltage detection circuit is provided and a battery voltage falls below a predetermined value during use, a message that warns of battery replacement or charging is displayed to alert the user.

[0004] However, at the stage when the message of battery replacement or battery charge is displayed, the user continues to use the battery because it is still usable. In some cases, a fatal trouble such as a malfunction below the allowable voltage during use and a malfunction of the memory or destruction of the memory contents may occur.

In order to prevent such a trouble, as disclosed in Japanese Patent Application Laid-Open No. 4-307613, in addition to a normal battery voltage detection circuit, a battery output voltage at the time of turning on a battery power is detected and a normal battery voltage detection circuit is used. A method was adopted in which a standard value higher than the voltage standard value of the battery voltage detection circuit was provided, and when this voltage was not detected, the battery power was not turned on and the electronic device did not operate.

FIG. 5 is a block diagram of a battery voltage detecting circuit when a power supply of an electronic device is turned on by a conventional method. In the figure, reference numeral 51 denotes a power switch, 52 denotes a battery, 53 denotes a voltage detection unit,
54, a mask circuit unit; 55, a DC / DC converter;
6 is an overall control unit, 60 is a keyboard, 61 is a memory, 6
Reference numeral 2 denotes a display unit.

[0007] Keyboard 60, memory 61, display unit 62
And other accessory elements (not shown) are controlled by a general control unit 56. The general control unit 56 is supplied with stabilized power from the battery 52 via a DC / DC converter 55 during operation. The operation is started by a power ON signal from the mask circuit unit 54, and the supply of power from the battery is also started.

When the power switch 51 is pressed by the user, a power switch signal from a backup battery (not shown) is transmitted to the mask circuit section 54. Voltage detector 53
Detects the output voltage of the battery 52, and sends a voltage drop detection signal to the mask circuit unit 54 when the output voltage is equal to or lower than a predetermined voltage standard value. The mask circuit section 54 is normally mask OFF, and receives a voltage drop detection signal, and turns mask ON.

Therefore, when the output voltage is equal to or higher than the predetermined voltage standard value, the mask is OFF, so that the power switch signal from the power switch 51 is transmitted to the overall control unit 56 and the DC / D
The stabilized power supplied from the battery 52 via the C converter 55 is supplied to each circuit via the overall control unit 56.

On the other hand, when the output voltage is equal to or lower than the predetermined voltage standard value, the mask is ON, so that the power switch signal of the power switch 51 is not transmitted to the overall control unit 56, so that the electronic device does not start operating and the battery is replaced. Alternatively, the state is maintained as if the power switch 51 was not pressed until the battery was charged.

[0011]

According to the method described above,
When the output voltage of the battery was lower than the specified value, the electronic device did not start and troubles such as malfunction due to voltage drop during use and destruction of memory recording could be prevented, but this method has the following problems. There was a point.

That is, the voltage of the battery fluctuates depending on the load current, and the voltage is restored after a lapse of time with a light load, and the voltage is rapidly reduced by use when the remaining capacity is small. Therefore, in order to determine the remaining capacity based on the voltage before startup, it is necessary to set the detection specified value to a high value. As well as the cost of discarding batteries that are still usable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery-driven electronic device capable of effectively estimating a remaining battery capacity based on a battery voltage, preventing an accident caused by a voltage drop during use, and economically performing battery replacement. Another object of the present invention is to provide a protection method when the battery capacity of an electronic device is low.

[0014]

The battery-driven electronic device of the present invention has a general control unit that uses a battery as a power source for driving, and receives power from the battery to start the electronic device upon receiving a power ON signal. In an electronic device, a pulse generator that generates a pulse signal having a fixed time width when the power is turned on, a discharge unit that receives the pulse signal and discharges electricity stored in the battery for a specified time, and detects a voltage of the battery. A voltage detection unit that generates a voltage drop signal when the detected voltage falls below a preset standard value, a delay circuit unit that receives a pulse signal and transmits a power-on signal delayed for a predetermined time, and a delay circuit unit. When the power supply ON signal is received from the power supply unit and the voltage drop detection signal is not transmitted from the voltage detection unit, the power supply ON signal is transmitted to the overall control unit, and the voltage drop detection signal is transmitted from the voltage detection unit. And a mask circuit for sometimes off the power supply ON signal.

Further, the discharge unit may include a luminous body that generates light at the time of discharge, and the discharge unit may include a sounding body that generates a sound at the time of discharge.

Further, the electronic device may be portable.

According to the protection method of the present invention when the battery capacity of an electronic device is low, the electronic device includes an overall control unit that uses a battery as a power source for driving, receives a power ON signal, receives power from the battery and starts the electronic device. This is a protection method when the battery capacity of the device is low.When the power is turned on, the battery possesses the battery and discharges the battery for a predetermined time, compares the battery voltage after the discharge with a predetermined voltage specification value, and determines whether the battery voltage after the discharge is high. If the voltage falls below the predetermined voltage, the power supply ON signal to be sent to the overall control unit is cut off, the electronic device is not started, and if the battery voltage after discharging does not fall below the voltage predetermined value, the power is turned on. A signal is sent to the overall control unit to activate the electronic device.

When the power switch is turned on, the battery is discharged for a certain period of time by a pulse, so that the influence of voltage return due to the passage of time with a light load is eliminated, and the battery is compared with a specified value at a battery voltage close to the actual use. Thus, ON and OFF of the mask are determined, and it is determined whether or not continuous use is possible.

When the battery voltage after discharging falls below a specified value, the power switch signal transmitted to the mask circuit section with a delay by the delay circuit section is masked, and the electronic device automatically becomes inoperable. Accidents caused by the descent are prevented beforehand.

Further, by discharging the battery for a certain period of time using a light emitting body or a sounding body, the power switch ON operation can be confirmed, and whether the inoperability of the electronic device is due to a decrease in the battery capacity or whether the power switch is turned off. It can be determined whether it is due to a non-operation.

[0021]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a battery voltage detection circuit when a power supply of an electronic apparatus according to a first embodiment of the present invention is turned on. FIG. 2 is a time chart of the operation of each signal in FIG. The state at the time of normal operation, (b) is a state at the time of insufficient voltage / masking. In the figure, reference numeral 11 denotes a power switch, 12 denotes a battery, 13 denotes a voltage detection unit, 14 denotes a mask circuit unit, 15 denotes a DC / DC converter, 16 denotes a general control unit, 17 denotes a pulse generation unit, 18 denotes a discharge unit, and 19 denotes a discharge unit. A delay circuit unit, 20 a keyboard, 21 a memory, 22 a display unit, 101 a power switch signal, 102 a pulse signal,
103 is a delayed power pulse signal, 104 is a battery voltage signal, 105 is a voltage drop detection signal, and 106 is a power ON signal to the overall control unit.

The keyboard 20 and the memory 21 of the electronic device
The display unit 22 and other accessory elements (not shown) include the overall control unit 1
6 and the overall control unit 16 has a DC /
The stabilized power is supplied from the battery 12 via the DC converter 15, and the overall control unit 16
, And the supply of power from the battery is also started.

When the power switch 11 is depressed, a power ON signal is generated as a power switch signal 101 by a backup battery (not shown), shaped into a pulse signal 102 for a fixed time by the pulse generator 17 and transmitted to the pulse signal circuit. . The pulse signal transmitted to the discharging unit 18 defines a discharging time in the discharging unit 18, and the discharging unit 18 discharges electricity stored in the battery 12.

The pulse signal 102 sent to the pulse signal circuit is also transmitted to the delay circuit section 19. The delay circuit section 19 delays the transmitted pulse signal 102 by a predetermined time and sends it to the mask circuit section 14.

On the other hand, the voltage detecting section 13 detects the output voltage of the battery 12, and when the output voltage falls below a predetermined voltage standard value, the voltage drop detecting signal is sent to the mask circuit section 14 via the voltage drop detecting signal circuit. The signal 105 is continuously transmitted. The mask circuit 14 is always masked OFF, and is turned ON when a voltage drop detection signal is received.

Accordingly, when the output voltage is equal to or higher than the predetermined voltage specification value, the mask is OFF. If the output voltage of the battery does not fall below the predetermined voltage specification, the delayed pulse signal from the delay circuit section 19 is applied to the mask circuit section. 14, the pulse signal is transmitted to the overall control unit 16 to activate the overall control unit 16, and the stabilized power supplied from the battery 12 via the DC / DC converter 15 is transmitted to the overall control unit 1
6 to each circuit.

On the other hand, when it is detected that the output voltage has become equal to or lower than the predetermined voltage specification value, the mask is turned on thereafter. Therefore, when the output voltage of the battery becomes equal to or lower than the predetermined voltage specification value after discharging, the delay circuit Even if the delayed pulse signal from the section 19 is input to the mask circuit section 14, it is cut off and the pulse signal is not transmitted to the general control section 16, so that the electronic device does not start operation and the battery is replaced or charged. Until the power switch 11 is not pressed, the same state is maintained.

Unlike the conventional example described above, the power switch 11
When the button is pressed, the battery is once discharged for a short time to eliminate the effect of voltage return due to the passage of time under a light load, and the voltage after the removal of the effect is compared with a reference value, and the battery is discharged. Has been determined. By delaying the power supply pulse signal by the delay circuit unit, the electronic device is activated according to the determination.

Next, the operation of the embodiment of the present invention will be described in detail with reference to FIG. FIG. 2A shows a temporal change in the state of each signal or voltage during normal operation. Here, the normal operation means that the battery has a sufficient capacity for the operation of the apparatus, and the apparatus normally operates with the power turned on.

First, when the power switch 11 is pressed, the power switch signal 101 is at a low level while being pressed. This signal is shaped into a pulse signal for a fixed time by the pulse generator 17 to become a pulse signal 102.

Next, the discharging section 18 receives the pulse signal 102 and discharges the connected battery. As a result, a voltage drop of (the internal resistance of the battery × discharge current) occurs in the battery voltage 104. At this time, the dropped battery voltage 104 is the standard value 1
07, the voltage drop detection signal 105 is not generated, so that the mask circuit unit 14 does not perform the masking by the voltage drop detection signal 105, and the mask circuit unit 1
4 is transmitted to the overall control unit 16 as a power-on signal 106 to the overall control unit, and the electronic device starts operating. At this time, a voltage drop occurs in the battery voltage 104 according to the load at that time.

FIG. 2B shows a temporal change in the state of each signal or voltage at the time of insufficient voltage / masking. Here, when the voltage is insufficient or at the time of masking, the power of the apparatus is turned on because the battery capacity is small.
It means that the signal is masked.

The description up to the point where the discharge unit 18 discharges by the pulse signal 102 is the same as that described with reference to FIG. 2A, but this time is a case where the internal resistance of the battery is large because the remaining capacity of the battery is small. . Therefore, the voltage of the battery is largely dropped due to the discharge in the discharge unit 18, and is lower than the voltage drop detection standard value 107. Therefore, the voltage drop detection signal 105 becomes high level thereafter, so that the mask of the mask circuit section 14 is turned on, and the delayed power supply pulse signal 103 transmitted to the mask circuit section 14 is masked and transmitted to the overall control section 16. The electronic device does not start operating.

In this embodiment, a keyboard, a memory,
Although the present invention has been described with reference to an electronic device having a display portion, the present invention is naturally applicable to all battery-driven electronic devices.

Although the present invention can be effectively applied to a portable electronic device using a battery as a power source, an electronic device using a battery as a power source or a battery as a power source without being a portable type device is also possible. Of course can be applied.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram of a battery voltage detection circuit when the electronic device according to the second embodiment of the present invention is powered on. In the figure, reference numeral 31 denotes a power switch, 32
Is a battery, 33 is a voltage detector, 34 is a mask circuit, 35
Is a DC / DC converter, 36 is an overall control unit, 37 is a pulse generation unit, 38 is a light emitting unit, 39 is a delay circuit unit, 301
, A power switch signal; 302, a pulse signal; 303, a delayed power pulse signal; 304, a battery voltage signal;
5 is a voltage drop detection signal, and 306 is a power supply O to the overall control unit.
N signal.

In the second embodiment, the discharge section 18 of the first embodiment is replaced with a light emitting section 38. When the luminous body emits light using the luminous body, the luminous body emits light at the same time as the discharge.Therefore, there is not enough battery capacity left to operate the electronic device, but there is still enough capacity to emit the luminous body However, when the power is turned on, the electronic device does not operate, but the luminous body emits light, so that it is possible to inform the operator that the electronic device does not operate due to insufficient battery capacity.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram of a battery voltage detection circuit when the electronic device according to the third embodiment of the present invention is powered on. In the figure, reference numeral 41 is a power switch, 42
Is a battery, 43 is a voltage detection unit, 44 is a mask circuit unit, 45
Is a DC / DC converter, 46 is an overall control unit, 47 is a pulse generator, 48 is a sound generator, 49 is a delay circuit, 401
Is a power switch signal, 402 is a pulse signal, 403 is a delayed power pulse signal, 404 is a battery voltage signal, 40
5 is a voltage drop detection signal, and 406 is a power supply O to the overall control unit.
N signal.

In the third embodiment, the discharge unit 18 of the first embodiment is replaced with a sound generator 48. When the sound is emitted using the sounding body, the sounding body emits a sound at the same time as the discharge, so there is not enough battery capacity left to operate the electronic device, but there is still enough capacity to sound the sounding body. However, when the power is turned on, the electronic device does not operate, but the sounding body emits a sound, so that it is possible to notify the operator that the operation is not performed due to the shortage of the battery capacity.

[0040]

As described above, according to the present invention, when the power switch is turned on, the battery is discharged for a certain period of time by a pulse, and the influence of the return of the voltage due to the lapse of time under a light load is eliminated. There is an effect that the ON / OFF of the mask is determined as compared with the specified value at a close battery voltage, and whether or not the continuous use is possible is determined.

When the battery voltage after discharging is lower than the specified value, the power switch signal transmitted to the mask circuit section with a delay by the delay circuit section is masked, and the electronic device automatically becomes inoperable, and the voltage drop occurs. This has the effect of preventing an accident caused by the accident.

Further, by discharging the battery for a certain period of time by using a light emitting body or a sound emitting body, it is possible to confirm that the power switch is turned on. An effect is obtained that it can be determined whether or not the operation is due to a non-operation.

[Brief description of the drawings]

FIG. 1 is a block diagram of a battery voltage detection circuit when a power supply of an electronic device according to a first embodiment of the present invention is turned on.

FIG. 2 is a time chart of the operation of each signal in FIG. 1;
(A) is a state at the time of normal operation. (B) Insufficient voltage
This is the state at the time of masking.

FIG. 3 is a block configuration diagram of a battery voltage detection circuit unit when a power supply of an electronic apparatus according to a second embodiment of the present invention is turned on.

FIG. 4 is a block configuration diagram of a battery voltage detection circuit unit when a power supply of an electronic apparatus according to a third embodiment of the present invention is turned on.

FIG. 5 is a block diagram of a battery voltage detection circuit when power is supplied to an electronic device according to a conventional method.

[Explanation of symbols]

 11, 31, 41, 51 Power switch 12, 32, 42, 52 Battery 13, 33, 43, 53 Voltage detection unit 14, 34, 44, 54 Mask circuit unit 15, 35, 45, 55 DC / DC converter 16, 36, 46, 56 Overall control unit 17, 37, 47 Pulse generation unit 18 Discharge unit 19, 39, 49 Delay circuit unit 20, 60 Keyboard 21, 61 Memory 22, 62 Display unit 38 Light emission unit 48 Sound generation unit 101 Power switch signal 102 pulse signal 103 delayed power pulse signal 104 battery voltage signal 105 voltage drop detection signal 106 power ON signal to overall control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02J 7/00-7/12 H02J 7/34-7/36 G01R 31/36 G06F 1/28

Claims (5)

(57) [Claims] 1. An electronic device having a general control unit that uses a battery as a power source for driving and receives power from the battery to start an electronic device when a power ON signal is received, wherein a pulse signal having a fixed time width when the power is turned on. A pulse generator for receiving the pulse signal and discharging the electricity held in the battery for a prescribed time; detecting a voltage of the battery, and detecting the detected voltage with a preset standard. A voltage detection unit that generates a voltage reduction signal when the voltage falls below the value; a delay circuit unit that receives the pulse signal and transmits a power-on signal delayed by a predetermined time; and receives the power-on signal from the delay circuit unit. Transmitting a power ON signal to the overall control unit when the voltage drop detection signal is not transmitted from the voltage detection unit;
A battery-driven electronic device, comprising: a mask circuit unit that shuts off the power-on signal when a voltage drop detection signal is transmitted from the voltage detection unit. 2. The battery-driven electronic device according to claim 1, wherein the discharge unit includes a luminous body that generates light at the time of discharge. 3. The battery-driven electronic device according to claim 1, wherein the discharge unit includes a sounding body that generates a sound when discharging. 4. The battery-driven electronic device according to claim 1, wherein the electronic device is portable. 5. A method of protecting a battery capacity of an electronic device having a general control unit that uses a battery as a power source for driving and receives an electric power from the battery when receiving a power ON signal and starts the electronic device. When the power is turned on, discharge the electricity held by the battery for a predetermined time, compare the battery voltage after discharge with a predetermined voltage specification value, and when the battery voltage after discharge falls below the predetermined voltage value, If the power supply ON signal to be sent to the overall control unit is cut off and the electronic device is not activated, and the battery voltage after discharging does not fall below the predetermined voltage value, the power ON signal is transmitted to the overall control unit. A protection method when the battery capacity is low, which is sent to a control unit to activate the electronic device.