JP3232596B2 - Battery level display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for displaying a remaining amount of a secondary battery which is a power source of a portable electronic device.

[0002]

2. Description of the Related Art Battery level display devices are generally of the battery voltage detection type, which is advantageous in terms of cost, and most of them are built in and used in the main body of a portable device or a battery pack (for example, JP-A-1-100479). Gazette).

A conventional battery remaining amount display device will be described below with reference to the drawings. FIG. 3 is a configuration diagram showing a conventional battery remaining amount display device. In FIG. 3, reference numeral 1 denotes a secondary battery, and 4 denotes battery voltage comparing means. Voltage comparators 41, 42 and 43 and a voltage source 48 for generating a predetermined reference voltage at the input thereof and a divided voltage at the other input. Resistors 44, 45, 46,
47 and a voltage dividing circuit for battery voltage.
Reference numeral 5 denotes display means for displaying the remaining battery level based on a signal from the battery voltage comparison means 4. Reference numeral 6 denotes a load corresponding to a portable device.

The operation of the conventional battery remaining amount display device configured as described above will be described below.

First, when the load 6 operates, the secondary battery 1 is discharged, and its voltage gradually decreases. This battery voltage is used as a voltage dividing point voltage of a voltage dividing circuit by a voltage comparator 4.
1, 42, and 43, and are compared with a predetermined reference voltage output from a voltage source 48. At 1.0 C discharge, the voltage comparator 41 detects the remaining battery level of less than 10%, the voltage comparator 42 detects the remaining battery level of less than 30%, and the voltage comparator 43 detects the remaining battery level of less than 60%. Resistances 44, 45, 46,
47 and a voltage source 48 are set, and the display means 5 displays 100% or less, 60% or more, less than 60%, 30% or more, less than 30%, 10% or more, 1% or less based on the output of each voltage comparator.
The remaining battery level is displayed in four stages of less than 0%.

[0006]

However, in the above configuration, the remaining battery level is detected only by the battery voltage.
In applications such as camera-integrated video, word processors, and mobile phones, the discharge current changes every moment, and the battery voltage also fluctuates. Therefore, there is a problem that the display differs depending on the discharge current and the remaining amount cannot be accurately displayed.

FIG. 2 is a characteristic diagram showing the relationship between the battery voltage and the remaining amount detection voltage depending on the difference in the discharge current. When the remaining amount detection voltage is constant regardless of the discharge current, the remaining amount is larger than the discharge current. It is different.

The present invention solves the above problems,
An object of the present invention is to provide a battery remaining amount display device whose display is constant regardless of a discharge current.

[0009]

In order to achieve this object, a battery remaining amount display device according to the present invention comprises a current detecting means for measuring the magnitude of a discharge current, and a battery divided by a dividing resistor.
Battery voltage comparing means for detecting a battery voltage by a plurality of voltage comparators which receive the respective voltage dividing point voltages and a common reference voltage as input, and display means for displaying a remaining battery level by an output of the battery voltage comparing means. And flowing a minute current proportional to a value detected by the current detecting means into a voltage dividing point of the highest potential of the divided resistor, thereby increasing and decreasing each of the discharge currents in proportion to an increase or decrease of the discharge current.
It has a configuration provided with comparison voltage correction means for increasing and decreasing the voltage at the division point.

[0010]

The battery remaining amount display device of the present invention has a battery voltage divided by a dividing resistor which is an input of a voltage comparator in the battery voltage comparing means by a comparison voltage correcting means which receives a value detected by the current detecting means as an input . Each divided voltage is corrected according to the discharge current, and the remaining voltage is increased in proportion to the increase or decrease of the discharge current.
It causes reduction. By appropriately setting the correction rate, the display can be made constant regardless of the discharge current.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a secondary battery, and 2 denotes current detection means for converting a discharge current into a voltage. Reference numeral 3 denotes comparison voltage correction means for outputting a small current proportional to the output voltage which is the value detected by the current detection means 2. Other configurations are basically the same as those in FIG. 3, and the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

The operation of the battery remaining amount display device of the present invention configured as described above will be described below.

First, the operation of the load 6 causes the secondary battery 1 to be discharged, and its voltage gradually decreases. The discharge current is converted into a voltage by the current detection means 2, and the detected value is input to the comparison voltage correction means 3. The comparison voltage correction means 3 outputs a very small current according to the input voltage, that is, in proportion to the discharge current. This output current is input to the contact point between the resistor 44 and the resistor 45, and increases each voltage dividing point voltage of the voltage dividing circuit in proportion to the discharge current. Therefore, the battery voltage at the time when these divided point voltages fall below the predetermined reference voltage decreases in proportion to the increase in the discharge current. Voltage comparators 41, 42, 43
Compares each of the battery voltages divided by the dividing resistor, that is, each voltage dividing point voltage with a predetermined common reference voltage, and outputs a result. The voltage comparator 41 detects the remaining battery level of less than 10%, the voltage comparator 42 detects the remaining battery level of less than 30%, and the voltage comparator 43 detects the remaining battery level of less than 60%. , 46, 47, the voltage source 48, and the output current of the comparison voltage correction means 3 are set, and the display means 5 displays 100% or less, 60% or more, less than 60% and 30% or more based on the output of each voltage comparator. Less than 30% 10% or more, 1
The remaining battery level is displayed in four stages of less than 0%.

As described above, according to the present embodiment, the current detecting means 2 for converting the discharge current into a voltage, and the comparison voltage correcting means 3 which receives the converted voltage as an input and outputs a minute current proportional to the input voltage A battery that injects this minute current into the highest potential voltage dividing point of the voltage dividing circuit and detects a drop in battery voltage with each voltage comparator that receives each voltage dividing point voltage and a predetermined common reference voltage as inputs. By providing the voltage comparison means 4 and the display means 5 for displaying the remaining amount value based on the signal of the battery voltage comparison means 4, it becomes possible to increase or decrease the remaining amount detection voltage in proportion to the increase or decrease of the discharge current. By setting the correction rate of the comparison voltage correction means 3 appropriately, the display can be made constant regardless of the discharge current. FIG. 2 shows that when the remaining amount detection voltage is appropriately reduced in proportion to the discharge current, the remaining amount value is constant regardless of the discharge current.

In this embodiment, the comparison voltage correction means 3 outputs a small current proportional to the input voltage and injects it into the highest potential voltage dividing point of the voltage dividing circuit. The output voltage may be reduced, and this may be used as a reference voltage instead of the voltage source 48.

[0017]

As described above, according to the present invention, the current detecting means for measuring the magnitude of the discharge current, the plurality of voltage dividing points of the battery voltage divided by the dividing resistor and the common reference voltage are inputted. Battery voltage comparing means for detecting the battery voltage by the number of voltage comparators, display means for displaying the remaining battery level by the output of the battery voltage comparing means, and dividing the minute current proportional to the value detected by the current detecting means. Proportionate to increase / decrease of discharge current by flowing to the highest potential division point of resistance
By providing the comparison voltage correcting means for increasing and decreasing each voltage dividing point voltage, it is possible to realize an excellent battery remaining amount display device in which the display is constant regardless of the discharge current.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram showing a relationship between a battery voltage and a remaining amount detection voltage depending on a difference in discharge current.

FIG. 3 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Current detection means 3 Comparison voltage correction means 4 Battery voltage correction means 5 Display means 6 Load

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/36 H01M 10/42-10/48 H02J 7/00

Claims (1)

(57) [Claims] 1. A battery voltage detector comprising: a current detecting means for measuring a magnitude of a discharge current; and a plurality of voltage comparators each of which receives a voltage dividing point voltage of a battery voltage divided by a dividing resistor and a common reference voltage. a battery voltage comparing means for detecting a and display means for displaying the remaining battery capacity by the output of the battery voltage comparator means, in proportion to the value detected by said current detecting means
Small current flows into the voltage dividing point of the highest potential of the divided resistor.
The voltage at each voltage dividing point in proportion to the increase or decrease of the discharge current.
A battery level display device comprising a comparison voltage correction means for increasing / decreasing the battery voltage.