JPH065265B2 - Battery remaining capacity display circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a battery that displays a remaining capacity of a battery in a battery-using device that shares a battery to be a remaining capacity display target and a battery as a power source of an arithmetic control unit. The present invention relates to a remaining capacity display circuit.

BACKGROUND ART Conventionally, as a remaining capacity display circuit of this type of battery, there is one that calculates and displays the remaining capacity of a storage battery by an arithmetic control circuit. However, when the storage battery as the target of the remaining capacity display and the storage battery as the power source of the arithmetic control circuit are shared, if the remaining capacity of the storage battery decreases and the voltage applied to the arithmetic control circuit decreases, the arithmetic control A large error may occur in the display of the remaining capacity due to the malfunction of the circuit.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to provide a remaining capacity of a battery capable of preventing a malfunction of an arithmetic control circuit to prevent a display error. It is to provide a display circuit.

DISCLOSURE OF THE INVENTION (Embodiment) FIG. 1 is a diagram showing an embodiment of the present invention. A charging circuit 8 for charging a storage battery 1 and a discharging circuit 4 for discharging the storage battery 1 by turning on a switch 2. And a current detection resistor 3 inserted between the switch 2 and the discharge circuit 4 for detecting the discharge current of the storage battery 1, and the voltage generated by the discharge current across the current detection resistor 3 is converted into a digital value. A /
A D converter 5, an arithmetic control circuit 6 as arithmetic control means for detecting the remaining capacity of the storage battery 1 from the output of the A / D converter 5, and a display means for displaying the remaining capacity detected by the arithmetic control circuit 6. A display circuit 7, a power supply circuit 10 for supplying power to each of the above-mentioned parts by boosting the voltage of the storage battery 1, and an electronic switch as a switching element for controlling the supply of the power supply of the power supply circuit 10 to the arithmetic control circuit 6. 9 and 9 form a remaining capacity display circuit. The display circuit 7 includes a display holding unit such as a latch circuit that holds a display when the capacity of the storage battery 1 drops below a predetermined value.

The operation of this embodiment having the above-mentioned circuit configuration is as follows. First, the display method of the display circuit 7 will be described with reference to FIG. The figure (a) shows the relationship of the capacity and voltage of the storage battery 1 with respect to discharge time, and the figure (b) has shown that the display by the display circuit 7 is four-step display of A, B, C, D. . Here, as shown in the curve (shown by the thick line a in the figure) showing the relationship between the discharge time and the voltage of the storage battery in FIG. 6A, the voltage of the storage battery 1 significantly decreases with respect to the discharge time. Until the capacity of the storage battery 1 becomes almost zero, the capacity of the storage battery 1 drops sharply. Here, the thin line B indicates a change in battery capacity. Next, the operation of the entire remaining capacity display will be described with reference to the flowchart of FIG. First, when the charging circuit 8 operates and the storage battery 1 is charged, the reference capacity a previously obtained by measurement or the like is initially set as the remaining capacity z. Next, when the switch 2 is turned on and the discharge is started in the discharge circuit 4, a voltage is generated in the battery detection resistor 3. Then, this voltage is input to the arithmetic control circuit 6 through the A / D converter 5, the arithmetic control circuit 6 detects the discharge current I, the discharge current I is integrated to obtain the integrated value It, and the initial setting is performed. The integrated value It is subtracted from the calculated remaining capacity z to obtain the remaining capacity of the storage battery 1. This remaining capacity z is displayed by the display circuit 7.
Will be displayed in four stages. The above operation is performed until the discharge is completed. Here, in the present embodiment, whether the remaining capacity z is larger than a predetermined value b before the arithmetic control circuit 6 determines whether to change from the discharge state to the charge state (“charge?” In the figure). Is determined (indicated by “z> b” in the figure). When the arithmetic control circuit 6 determines that the remaining capacity z is smaller than the predetermined value b, the arithmetic control circuit 6 controls the display circuit 7 so as to hold the display, and the arithmetic control circuit 6 itself is controlled by the electronic switch 9. The arithmetic control circuit 6 controls the electronic switch 9 so as to stop the supply of the power. Here, the predetermined value b is a value corresponding to the D state of the four-step display of FIG. 2 (b). In the above-described operation, the operation of detecting the remaining capacity z of the arithmetic control circuit 6 is not performed, and the display circuit 7 also holds the display D state as the constant remaining capacity z. Therefore, the wrong remaining capacity z is displayed. There is no. Needless to say, even if the power supply to the arithmetic control circuit 6 is stopped, the display circuit 7 maintains the display state of the remaining capacity. Further, in the present embodiment, the remaining capacity is displayed in the four-level display D
When the predetermined value corresponding to the display (minimum capacity display) is reached, the arithmetic control circuit 6 performs the display holding output, and this display holding output is also used as the display output for D display. Next, the power supply to the arithmetic control circuit 6 is restored by, for example, the rise of the voltage (or the fall at the end of the charge) that occurs when charging is started across the Zener diode provided on the AC power supply side of the charging circuit 8. Electronic switch 9
Is turned on to supply power to the arithmetic control circuit 6.

[Effects of the Invention] As described above, the present invention includes the calculation control means for detecting the remaining capacity of the battery, and the display means for displaying the remaining capacity which is the detection result from this calculation control means in stages, and displays the remaining capacity. In the battery remaining capacity display circuit that displays the remaining capacity of the battery in a battery-using device that shares the target battery of the above and the battery as the power source of the arithmetic control means, the battery capacity corresponds to the final stage display of the display means. When the voltage drops below a predetermined value, a display holding means for holding the final display on the display means is provided in the display means, and when the battery capacity drops below the predetermined value, power is supplied to the arithmetic control means. A switching element for stopping is provided, and when the battery capacity falls below a predetermined value corresponding to the final display on the display means, the switch is for stopping the power supply to the arithmetic control means. Since the battery element is provided, when the battery capacity drops below a predetermined value corresponding to the final display on the display means, the arithmetic control means is not operated and fluctuations in the current consumption of the device using the battery (so-called load fluctuations) and It is possible to prevent the influence control means from malfunctioning by preventing the influence of noise or the like. Further, since the display holding means is provided in the display means for holding the last-stage display on the display means when the battery capacity drops below a predetermined value corresponding to the last-stage display on the display means, the operation of the arithmetic control means is stopped. In this case, it is possible to prevent the remaining capacity display from disappearing. Therefore, if the drive limit voltage of the arithmetic control unit is higher than the drive limit voltage of the load driven by the battery, the load cannot be driven. The battery can be used up, and deterioration of the battery due to repeated charging with the battery capacity remaining can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic circuit configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a display method of the above, and FIG. 3 is an operation explanatory diagram of the same. 1 is a storage battery, 4 is a discharge circuit, 6 is an arithmetic control circuit, 7 is a display circuit, 8 is a charging circuit, 9 is an electronic switch, and 10 is a power supply circuit.

Claims (1)

[Claims] 1. A calculation control means for detecting a remaining capacity of a battery,
In a battery-using device that includes a display unit that displays the remaining capacity, which is the detection result from the calculation control unit, in stages, and a battery that is a target of the remaining capacity display and a battery as a power source of the calculation control unit. In the battery remaining capacity display circuit for displaying the remaining capacity, the display means is provided with a display holding means for holding the last-stage display in the display means when the battery capacity falls below a predetermined value corresponding to the last-stage display of the display means. At the same time, a battery remaining capacity display circuit provided with a switching element for stopping the supply of power to the arithmetic control means when the battery capacity drops below the predetermined value.