JPS5928678A - Display device of residual electric power of battery - Google Patents

Abstract

PURPOSE:To display the residual electric power of a battery, by integrating the electric current flowing in a load with time. CONSTITUTION:A resistance 1 is a resistance for current detection which is interposed between a battery 2 and a load (not shown). An amplifier 3 amplifies the slight voltage drop at both terminals of the resistance and yields the signal proportional to the current flowing in the resistance 1 as its output. This output signal is converted to about 4-6 bit digital signal by an AD converter 4 and the digital signal is transmitted to the adder 5a of a cumulator 5. The adder 5a outputs the output of the converter 4 and the output fed back from a register 5b and transmits the same to the register 5b. The register 5b reads the output of the adder 5a by the clock pulses transmitted from a clock pulse generator 6 and stores the same. Thus the output of the adder 5a indicates the time-integrated value of the current flowing in the resistance 1. A display device 7 displays the content of the register 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a battery power remaining amount display device that integrates the amount of liquid flowing into a load so that the amount of power remaining in the battery can be easily known.

In the case of conventional portable video, when the battery discharges, the lamp indicating voltage shortage 1 lights up and stops. FIG. 1 is a characteristic diagram of a nickel-cadmium battery commonly used as the 7-inch battery. The portable video is rated at 12V and has a voltage of 10V.
．． It stops when it drops to 5 V, so 10
．． At 7■, a warning lamp is lit. As is clear from Figure 1, this type of battery has a characteristic sound that drops rapidly when the voltage begins to drop. Incidentally, the warning voltage is 10.7V and the stop voltage is 10.
There is only about 30 seconds to fall at 5Vt. Because the battery suddenly runs out like this, you must always carry a spare battery with you.

On the other hand, for portable videos that require convenience and length, especially 8m videos that have recently been developed, spare cassettes are particularly important, and carrying a spare battery is not desirable as it impairs the above-mentioned features. However, since the characteristics of the -9 battery are as shown in FIG. 1, detection based on voltage makes it unusable within a short period of time after the warning of insufficient voltage9, so it is necessary to carry a spare battery.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a connoisseur remaining battery power display device that can easily and accurately determine how many minutes of remaining battery life is left. The technical concept of the present invention, which achieves this object, is based on the fact that the amount of power remaining can be known from the amount of power used by accumulating the current flowing through the load.

Embodiments of the present invention will be described in detail below based on the drawings. As shown in FIG. 2, a resistor 1 is a resistor for current detection and is interposed between a battery 2 and a load (not shown). The amplifier 3 amplifies the weak voltage drop across the resistor 1, and obtains a signal proportional to the current flowing through the resistor 1 as its output. This output signal converter 4
The signal is converted into a digital signal of about 4 to 6 bits and sent to the adder 5alC of the accumulator 5. Adder 5
The output of the A/D converter 4 and the output of the A/D converter 4, which has been packed together with the outputs of the A/D converter 4 and the outputs of the A/D converter 4, are added together and sent to the register 5b.

The register 5b reads and stores the output of the adder 5a using a clock pulse sent from the clock pulse generator 6. Thus, the output of the adder 5a represents the time integral value of the current flowing through the resistor 1. The display 7 is for displaying the contents of the register 5b, for example 10.
It is possible to arrange all the liquid crystals in a rod shape. At this time, the cumulative amount of current consumption is displayed as each of 10 steps, so if the full scale corresponds to the capacity of battery 2, the remaining power can be displayed by the length of the bar created by the LCD. Furthermore, in order to improve the display accuracy of this type of remaining battery power display device, the ambient temperature and self-discharge of the battery 2 must be taken into consideration. This is because the characteristics of the battery 2 generally depend on temperature, and it can be used for a longer time when the temperature is high, and losses due to self-discharge inevitably occur over time. In the non-embodiment, as a measure against the former, the dyne of the amplifier 3 is changed by the resistance temperature element 8. That is, amplifier 3
A resistance temperature element 8 such as a thermistor is used as a feedback resistance for the ambient temperature, and the gain can be lowered when the ambient temperature becomes higher, and the dyne is increased when the ambient temperature becomes lower. Further, in this embodiment, as a countermeasure against the latter problem, the clock pulse of the clock pulse generator 6 is used for time measurement. That is, the clock pulses of the clock pulse generator 6 are counted by the counter Z9, and when the count reaches a predetermined number, in other words, when a predetermined time has elapsed and π, one pulse is added to the minimum digit of the adder 5a. I'll do it. Therefore, the count number may be set in consideration of the temporal self-discharge characteristics of the battery 2 and in correspondence with the temporal decrease in battery power.

In addition, since this embodiment has a self-discharge compensation function that uses a clock control for timekeeping, the accumulator 5 is activated even when the portable video to which this is applied is not used, that is, when the main switch connected to the battery 2 is opened. , the clock pulse generator 6 and the counter 9 must be powered up to function properly. However, in principle, such /< pull-up is performed only on register 5b.
, or even if the pull-up function is removed, the register
A non-volatile memory may be used as 5b. Furthermore, it goes without saying that the accumulator 5 and counter 9 must be cleared when the battery 2 is replaced, but this can be easily done by, for example, canceling the backup when the battery 2 is replaced. obtain.

In the above embodiment, it is assumed that the battery 2 is always replaced with a new one.

That is, if the product is replaced with a used product, the display will be incorrect.

However, it is quite conceivable that the user may exchange the item for a used item due to carelessness. This can be resolved by the following measures. That is, as shown in FIG. 3 [a], the battery 2
All the circuits shown in FIG. 2 may be integrated into the case 2a so that the display 7 can be viewed through the window 2b provided in the case 2&. Incidentally, since the circuit shown in FIG. 2 can be accommodated in an 8-pin IC package, there is no problem. This Yorinagu Tsuterry 2 is the 3rd
As shown in Figure (b), it is housed in a grip 10a of a portable video 10, for example, and the display 7 is made visible through a window 10bk provided in the grip 10a. Furthermore, clearing of the accumulator 5 etc. in this case can be easily accomplished by fully utilizing the charge completion signal.

As described above in conjunction with the embodiments, the present invention integrates the current flowing through the load over time, so that the remaining amount of battery power can be displayed. Therefore, when applied to portable video, for example, it is possible to leave the battery in a car or the like and safely go to a video location without carrying a spare battery.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram showing the characteristics of a nickel-cadmium battery, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3(a) shows the embodiment shown in Fig. 2 integrated into a battery case. FIG. 3(b) is an external view showing the case where the video camera is incorporated, and FIG. In the drawing, ■ is a resistor, 2 is a battery, 5 is an accumulator, and 7 is a display. Patent Applicant: Fuji Photo Film Co., Ltd. Representative: Patent Attorney: Shibe Motoishi (and one other person) Letter of Amendment 1981 Showa 5th Fi I Patent Application No. 137853-3 [
]1 B] Trial No. 2, Name of the invention Battery power level display device 3-1+1111 Relationship with the person IIf'l Patent applicant Fuji Photo Film Co., Ltd., 210 (520) Nakanuma, Minamiashigara City, Kanagawa Prefecture Shizuku: (Su 2nd Shishi 107
ゝ"-'Self "Detailed Description of the Invention" column of Invention #l. 7. Page 5, line 18 of the “Detailed Description of the Invention” column of the statement of contents of the amendment
Delete the phrase "Just use something like this..." written in the second line of page 6.

Claims (1)

[Claims] a resistor interposed between the battery and the load; an accumulator that detects the current flowing through the resistor and integrates it over time;
An LZ battery power remaining amount display device comprising: a display device that displays the remaining power amount of the battery based on the accumulated result of the accumulator.