JPH04265635A - Battery life display - Google Patents

Abstract

PURPOSE:To always equalize the residual quantity of a battery at the point of time of life display, regardless of the condition of battery, in a battery life display equipped with an auxiliary function. CONSTITUTION:This is a battery life display, which displays life by detecting the battery getting under the battery voltage detection level Vs being set beforehand to a fixed value with a battery voltage detecting means 1 and stopping or decelerating a motor M with a switching control means 2 and makes the battery B have auxiliary function by making the battery B and the motor M conductive compulsively by a switch SW2, and this is equipped with a level changing means (Rx, SW3) for lowering the above set battery voltage detection level Vs by a specified value.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a device for displaying a decrease in the remaining capacity of a battery in a battery-operated device such as an electric shaver, and more particularly, the present invention relates to a device for displaying a decrease in the remaining capacity of a battery in a battery-powered device such as an electric shaver. The present invention relates to a battery life display device that makes it possible to display battery life.

0002

[Prior Art] Conventionally, a battery life warning device has been proposed for the power supply circuit of this type of battery-applied equipment, which not only warns that the battery capacity is low but also has a backup function. Publication number 62-23333)
. This battery-applied device has a basic configuration in which a battery, a motor as a load, and a switching means are connected in series. Then, a plurality of dividing resistors are connected in series to the battery voltage, the divided voltage from the middle point is extracted as the battery voltage, and when this voltage drops to a predetermined level, the remaining capacity of the battery is considered to be low and the switching is performed. The motor is stopped by the means, and the LED is turned on as necessary. In this way, a warning is given that the battery capacity has become low enough to last one or two uses. The remaining usage amount can be forcibly made available by a separate switch.

0003

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 62-23
The battery life warning device described in Publication No. 333 is configured to be controlled when the voltage at the midpoint of two series voltage divider resistors connected in parallel to the battery voltage drops to a predetermined level, and the voltage detection level is initialized. The level is fixed at the level adjusted by VR. By the way, the curve shown in FIG. 4 is Ni-C
d shows the discharge characteristics of batteries, etc. In the discharge characteristics shown in Fig. 4, Vs is the voltage slightly before the battery voltage suddenly drops, and this voltage Vs is set as a detection level to issue a life warning that there is some remaining usage. be. Now, under normal conditions, the battery voltage is at this detection level Vs
It is assumed that the time for the drop to decrease to t0 is t0.

However, the discharge characteristics of a battery vary depending on its condition, and it does not always exhibit the discharge characteristics shown by the solid line in FIG. If this happens, the following problems occur.

That is, when the battery is repeatedly charged and discharged over a long period of time or due to frequent use, the discharge characteristics of the battery decrease as shown from the solid line to the broken line in FIG. 4, so if the detection level Vs remains fixed. , the time it takes to reach the above-mentioned warning time is shortened from t0 at the normal time to t0', and the remaining capacity of the battery at the warning time differs greatly. In other words, in the case of the discharge characteristic shown by the broken line, although t0'' is preferable as the warning time in order to make the remaining capacity at the warning time approximately equal, the system operates early at the above-mentioned time t0'. becomes.

[0006] Also, electric razors are usually equipped with a sharpening blade, and when the sharpening blade is activated by a switching operation, both the main blade and the sharpening blade are activated. As the load current increases, the discharge characteristics become as shown by the broken line in FIG. 4, and the warning level is reached at an early point such as t0'. Furthermore, the usage time for electric shavers varies depending on the user, and for those who use it for a long time,
If the detection level Vs remains fixed, there is a possibility that the remaining capacity will not reach the amount used even once. Further, as the environmental temperature increases, the discharge characteristics tend to decrease as shown by the broken line in FIG. 4, so if the detection level Vs is fixed, the variation in remaining capacity at the time of warning will be relatively large.

[0007] In this way, when the discharge characteristics of the battery deviate from the normal state as shown by the broken line, a warning is given that the capacity is low even though there is sufficient remaining capacity.
Not only does it become less convenient to use, but the reliability of the device also decreases.

The present invention has been made in view of the above, and
The detection level of the battery voltage can be changed as appropriate between the case where the battery has a normal discharge characteristic as shown by the solid line in Figure 4 and the case where the battery has the discharge characteristic as shown by the broken line in Figure 4, that is, under the above-mentioned usage conditions. It is an object of the present invention to provide a battery life display device in which the remaining battery capacity at the time of display is equal.

[0009]

[Means for Solving the Problems] The present invention detects that the battery voltage has become lower than a battery voltage detection level Vs, which is set to a certain value in advance, by a battery voltage detection means, and controls the motor to stop or decelerate. A battery life display device that displays the battery life by forcibly connecting the battery and the motor to provide a reserve function to the battery, and lowers the battery voltage detection level Vs set above by a predetermined value. It is equipped with a level changing means.

0010

[Operation] According to the present invention, as the motor is driven and the battery consumption progresses, the battery voltage gradually decreases. When the battery voltage drops to the battery voltage detection level Vs, which is set to a certain value in advance, the drive of the motor is stopped or the rotational speed is controlled to slow down, and a lifespan display indicating that the remaining battery capacity is low is displayed. will be held. In addition, there is a configuration that forcibly establishes conduction between the battery and the motor, and when conduction is established using this configuration, the motor can continue to be driven for the remaining capacity of the battery after the above-mentioned lifespan is displayed, and is used as a so-called reserve. The function works.

On the other hand, if it is determined that the discharge characteristics of the battery have decreased or will decrease, and the level changing means decreases the battery voltage detection level Vs by a predetermined value, the battery voltage decreases faster than when it is normal. However, since the battery voltage detection level is also lowered by a predetermined value from the above Vs,
The time at which the battery voltage drops to the changed battery voltage detection level Vs is delayed, and therefore, at the time of life display, the remaining capacity of the battery remains approximately the same as in the normal state.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of battery application equipment equipped with a battery life display device according to the present invention. The battery-applied equipment in FIG. 1 consists of a series circuit of a battery B, a motor M, a switching control section 2, and a main switch SW1, and a battery voltage detection section 1, and the switching control section 2 is controlled by a detection signal from the battery voltage detection section 1. It is made to be done. The main switch SW1 supplies energy from the battery B to the series circuit. SW2 is a forced switch disposed at a suitable location outside the main body of the device, and is connected in parallel between the emitter and collector of the switching element Q3 of the switching control section 2, and is a forced switch for activating a reserve function to be described later. It is preferable for use to employ a configuration in which when the forced switch SW2 is closed, the main switch SW1 is also closed.

The battery voltage detection section 1 includes series resistors R1 and R2.
, IC circuit 11, initial setting variable resistor VR1, resistor R
x and switch SW3. Series resistance R
1 and R2 are connected in parallel to the battery B and are for extracting the battery voltage, and the divided voltage at the midpoint of the resistors R1 and R2 is detected as the battery voltage. This extracted divided voltage is input to the IC circuit 11. The initial setting resistor Ro initializes the battery voltage detection level Vs, and is fixed at the time of adjustment at the manufacturing stage or at the time of shipment, for example. The IC circuit 11 compares the battery voltage detected by dividing the voltage as described above with the battery voltage detection level Vs, and outputs a high level detection signal when the battery voltage is equal to or higher than the battery voltage detection level Vs. Battery voltage is at battery voltage detection level V
When the voltage drops below s, a low level detection signal is output.

A series circuit consisting of a resistor Rx and a switch SW3 constitutes a level changing means, and the initial setting resistor R
o in parallel. This switch SW3 is a normally open contact type switch disposed at a suitable location outside the main body of the device so that it can be operated by the user. When this switch SW3 is open, the battery voltage detection level Vs is set only by the set resistance value of the initial setting resistor Ro. On the other hand, when the switch SW3 is closed, the battery voltage detection level Vs is set only by the set resistance value of the initial setting resistor Ro. A battery voltage detection level Vs'(<Vs, see FIG. 4), which is lower by a predetermined value than the battery voltage detection level Vs, is changed and set by the parallel resistance value of Ro and the resistance value of the resistor Rx.

[0015] The battery voltage detection level Vs is determined when the remaining capacity of the battery is a required amount, for example, in the case of an electric shaver, there is 1 to 1 remaining capacity.
An amount (number of times) that can be used about twice is preferable. This remaining capacity is set to an amount suitable for functioning as a reserve function, as will be described later. Note that R3 is a power supply resistor.

The switching control section 2 is composed of switching elements Q1, Q2, Q3 and resistors R4, R5. The above IC circuit 1 is attached to the base of the switching element Q1.
The detection signal from 1 is inputted. Switching elements Q1 and Q2 are Darlington connected,
The emitter of switching element Q2 is connected to battery B via resistor R4. Further, a resistor R5 is connected between the emitter and collector of the switching element Q2. The emitter and collector of the switching element Q3 are connected in series to the series circuit, and the base is connected to the collector of the switching element Q2.

As will be described later, the resistor R5 is a resistor having a fairly high resistance value in order to turn off the switching element Q3 when the motor is controlled to stop driving as a function of the switching control section 2, as will be described later. On the other hand, motor M
When performing deceleration control, a resistor having a required resistance value is used to make the switching element Q3 semi-conductive. In this way, the resistance value of the resistor R5 can be set as appropriate depending on the control form of the motor M. Note that the resistance value of the resistor R4 is set to such a value that the switching element Q3 is completely turned on when the switching element Q2 is turned on.

Next, the operation will be explained. Battery B is
When determining that the discharge characteristics shown by the solid line in FIG. 4 are normal, the switch SW3 is used with the switch SW3 open. When the main switch SW1 is turned on and the motor M is driven to rotate and the energy of the battery B is consumed, the battery voltage gradually decreases. During this time, if the battery voltage is equal to or higher than the battery voltage detection level Vs, the IC circuit 11 outputs a high-level detection signal. Therefore, switching elements Q1 and Q2 are turned on, a base current flows from battery B to the base of switching element Q3 via resistor R4, and switching element Q3 maintains the on state.

After that, when the battery voltage decreases to the battery voltage detection level Vs, the IC circuit 11 outputs a low level detection signal. Therefore, the switching element Q
1 and Q2 are turned off, and a base current flows from battery B to the base of switching element Q3 via resistors R4 and R5. Therefore, when the resistance value of the resistor R5 is a fairly high resistance value, the switching element Q3 is turned off and the rotation of the motor M is stopped.On the other hand, when the resistance value of the resistor R5 is not a high resistance value, the switching element Q3 is turned off. The motor M enters a semi-conducting state, and the rotational speed of the motor M is reduced due to a decrease in the load current. When the motor M stops or decelerates, the user is notified of the lifespan display and can know that the number of remaining uses is, for example, 1 or 2 times. When the battery is to be used subsequently, the remaining capacity can be used as a backup function by turning on the forced switch SW2 and forcibly supplying the energy of the battery B to the motor M.

When the condition of battery B has deteriorated as shown in the discharge characteristics shown by the broken line in FIG. 4, that is, when the device has been charged and discharged many times due to long-term or frequent use, the load current increases. If it is determined that the environment or battery temperature is high (such as when both the main blade and the diagonal blade are used), the switch SW3 is closed. switch SW
3, the battery voltage detection level is changed to Vs'(<Vs), and as a result, even if the battery discharge characteristics deteriorate, the IC
Since the time at which the circuit 11 outputs the low-level detection signal is delayed, the remaining capacity of the battery can be brought closer to equaling the remaining capacity during normal operation. Then, as described above, after the life is displayed, the reserve function can be operated with the remaining capacity close to normal by using the forced switch SW2.

FIGS. 2 and 3 are partial circuit diagrams showing other embodiments. FIG. 2 shows a system in which the battery voltage detection level is automatically changed with respect to the environmental temperature. That is, in FIG. 2, in the circuit diagram of FIG. 1, a temperature sensing element having negative temperature characteristics, such as a thermistor TH1, is provided in place of the resistor Rx and switch SW3.

The thermistor TH1 is provided, for example, in contact with or adjacent to the battery B, and adjusts the discharge characteristics of the battery by changing the parallel combined resistance value with the initial setting resistor Ro in accordance with changes in battery or environmental temperature. The battery voltage detection level corresponding to the above can be suitably set. That is, as the battery temperature and the environmental temperature rise and the discharge characteristics of battery B approach the broken line in FIG. Lower towards the side. In this way, since the battery voltage detection level is lowered in accordance with the rise in battery and environmental temperature, it is possible to make the remaining capacity of the battery at the time of life display equal to the remaining capacity of the battery during normal operation.

FIG. 3 shows how the battery voltage detection level is changed depending on the magnitude of the load current. In the same figure, R6
is a load current detection resistor connected in series with the series circuit and between load current detection terminals P1 and P2 of the IC circuit 11. For example, in an electric shaver, the load current is different when only the main blade is used and when both the main blade and the diagonal blade are used, and therefore the discharge characteristics of the battery are also different.

The IC circuit 11 reads the voltage generated across the load current detection resistor R6, and based on this detected voltage, determines whether the load current is large or small, or detects the load current value. . The IC circuit 11 internally stores a battery voltage detection level corresponding to the magnitude of the load current, or stores a battery voltage detection level corresponding to the load current, and detects the battery voltage corresponding to the load current or the magnitude of the load current. Levels are set. In other words, when the load current is large, the battery voltage detection level is set low, and when the load current is small, the battery voltage detection level is set high, so that the remaining battery capacity at the time of life display is always the same. I can do it.

[0025]

[Effects of the Invention] As explained above, according to the present invention,
Since the battery voltage detection level Vs, which has been set to a constant value in advance, is equipped with a level changing means that lowers it by a predetermined value as necessary, the remaining capacity of the battery at the time of life display is always displayed regardless of the state of use of the battery. This makes it possible to provide equipment that is easy to use and highly reliable.

[Brief explanation of the drawing]

FIG. 1 shows an example of a battery application device equipped with a battery life display device according to the present invention.

FIG. 2 is a partial circuit diagram showing another embodiment of the battery life display device.

FIG. 3 is a partial circuit diagram showing another embodiment of the battery life display device.

FIG. 4 shows the discharge characteristics of Ni-Cd batteries, etc.

[Explanation of symbols]

1 Battery voltage detection section 2 Switching control section 11 IC circuit B Battery M Motor R1, R2　Voltage dividing resistance R4, R5 resistance Rx resistance R6 Load current detection resistor SW1 Main switch SW2 Force switch SW3 Level change switch Q1~Q3 Switching element TH1 Thermistor Ro Initial setting resistor

Claims (1)

[Claims] Claim 1: A battery voltage detection means detects that the battery voltage has fallen below a battery voltage detection level Vs set to a certain value in advance, and controls the motor to stop or decelerate, thereby displaying the lifespan of the battery. A battery life display device that provides a reserve function to the battery by forcibly conducting between the motors, the battery voltage detection level V being set as described above.
A battery life display device comprising a level changing means for lowering s by a predetermined value.