KR19980079177A - Portable computer and remaining power display method with voltage display function of rechargeable battery - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery voltage display device and method for preventing overcharging and overdischarging of a battery in a computer system operated by a secondary battery. A battery voltage detector for generating a corresponding voltage signal; A battery temperature detector for detecting a temperature of the battery and generating a temperature signal corresponding to the detected temperature; A load current detector for detecting an amount of current flowing from the battery to the loads and generating a current signal corresponding to the detected amount of current; A microcomputer that calculates a residual amount of the battery based on the voltage information signal, corrects the calculated residual amount based on the temperature information signal and the load current information signal, and outputs a remaining battery information signal; And a display unit for displaying remaining amount information corresponding to the remaining amount information signal, and detecting the voltage of the battery and displaying the remaining amount of the battery. After calculating by considering the voltage fluctuations according to the standing time, the remaining battery capacity is corrected and displayed. Therefore, more accurate battery level can be displayed.

Description

Portable computer and remaining power display method with voltage display function of rechargeable battery

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery level display circuit, and more particularly, to a battery level display circuit and a method of a secondary battery (charger) used in a portable electronic device such as a notebook computer.

Batteries are largely divided into chemical cells and physical cells, and chemical cells can be divided into primary cells, secondary cells, and fuel cells. Among them, rechargeable batteries are widely used as batteries of portable computers.

Most secondary batteries generate gas internally when they are overcharged (continuous charge current or voltage flows in), but a small amount of gas is absorbed inside the cell. At this time, the greater the charging current, the greater the generation of gas may cause the rechargeable battery to rupture. Therefore, in designing a charging device of a secondary battery, the biggest problem is detecting the completion time of charging (full charge time). Conventionally, when the voltage of the battery pack is detected and inputted to the micom, the micom displays an LCD ( The remaining charge of the battery pack was output by using a liquid crystal display (LED) or a light-emitting diode (LED) or the like to determine the completion point of charging.

1 is a view for explaining an operation of displaying the remaining amount of a conventional secondary battery, Figure 2 is a flow chart showing the operation of FIG.

Referring to FIGS. 1 and 2, in the related art, a voltage between both terminals of the secondary battery is measured by a method of measuring the remaining amount of a battery, and the remaining amount is displayed as information based on the measured voltage.

This method is simple, but the exact battery level is unknown. In particular, nickel-cadmium or nickel-hydrogen secondary batteries hardly estimate the remaining amount in voltage because the terminal voltage hardly changes until the end of discharge.

In addition, due to the change in the voltage level of the battery pack according to the use conditions of the system (for example, temperature change, standing time after full charge, voltage change during full charge, load change), the remaining amount of output is in error.

Therefore, the present invention has been proposed to solve the above-mentioned problems, and has an object of detecting a voltage fluctuation factor and correcting the residual value according to the variation of the fluctuation factor to accurately measure the remaining battery level.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining a conventional display method of a residual battery level;

2 is a flow chart showing the operation of FIG.

3 is a graph showing a relation between a general voltage and a residual amount;

4 is a block diagram showing a schematic configuration of a secondary battery remaining amount display device of the present invention;

FIG. 5 is a view for explaining a method of displaying a secondary battery remaining amount in FIG. 4; FIG.

6 is a flow chart showing the operation of FIG. 4;

7 is a graph showing a voltage change characteristic of a secondary battery according to a temperature change;

8 is a graph showing the voltage change characteristics of the secondary battery according to the standing time after full charge;

9 is a graph showing a voltage change characteristic according to a discharge rate;

According to one aspect of the present invention proposed to achieve the above object, the apparatus for displaying the remaining amount of the secondary battery, the circuit for detecting the voltage of the battery, and generating a voltage signal corresponding to the detected voltage; ; Circuitry for detecting a temperature of the battery and generating a temperature signal corresponding to the detected temperature; Means for detecting an amount of current flowing from the battery to loads and generating a current signal corresponding to the detected amount of current; A circuit for calculating a residual amount of the battery based on the voltage signal and outputting a corrected residual amount information display signal by correcting the residual amount calculated by the temperature signal and the load current signal; And a circuit for displaying remaining amount information corresponding to the remaining battery level displaying signal.

In a preferred embodiment of the present invention, the secondary battery remaining indication display device comprises: a circuit for charging the battery; And a circuit for measuring the neglected time from full charge of the battery to before the start of its discharge and generating an idle time signal corresponding to the measured time.

In a preferred embodiment of this feature, the battery includes a dummyster for sensing its surface temperature.

According to another aspect of the present invention, a method comprising a battery, a battery voltage detector, a battery temperature detector, a load current detector, and a microcomputer, the method for displaying the remaining amount of the secondary battery comprises the steps of: detecting the voltage of the battery; Calculating a remaining amount of a battery by the detected voltage; Detecting remaining amount correction factors of the battery remaining value; Determining whether correction of the calculated remaining amount is necessary based on the remaining amount of battery correction factors; Correcting a residual amount deviation of the battery when operation correction is required; And displaying the corrected remaining amount.

In a preferred embodiment of this feature, the remaining battery correction factors include temperature, amount of load current, and time left from full charge of the battery.

In a preferred embodiment of this feature, the correcting step reduces the residual value by a value corresponding to the temperature deviation when the detected temperature of the battery is higher than the predetermined reference temperature, and conversely, when the detected temperature is lower than the reference temperature. And increasing the remaining value by a value corresponding to the temperature deviation.

In a preferred embodiment of this aspect, the correcting step increases the residual value by a value corresponding to the deviation of the load current when the detected load current is larger than the current when the normal load is applied. If less than the current, the process includes reducing the residual value by a value corresponding to the deviation of the load current.

In a preferred embodiment of this aspect, the correcting step increases the remaining value by a value corresponding to the leaving time, as the left time from the full charge of the battery to before the start of its discharge is measured, on the contrary, the leaving time. The shorter the process, the lower the remaining value.

The present invention relates to a secondary battery remaining amount display device and method for preventing overcharging and overdischarging of a battery in a computer system operated by a secondary battery, and detecting a voltage of the battery and corresponding to the detected voltage. A battery voltage detector for generating a voltage information signal; A battery temperature detector for detecting a temperature of the battery and generating a temperature information signal corresponding to the detected temperature; A load current detector for detecting an amount of current flowing from the battery to the loads and generating a current information signal corresponding to the detected amount of current; A microcomputer that calculates a residual amount of the battery based on the voltage information signal, corrects the calculated residual amount based on the temperature information signal and the load current information signal, and outputs a remaining battery information signal; And a display unit for displaying remaining amount information corresponding to the remaining amount information signal, and detecting the voltage of the battery and displaying the remaining amount of the battery. After calculating by considering the voltage fluctuations according to the standing time, the remaining battery capacity is corrected and displayed. Therefore, more accurate battery level can be displayed.

4 is a schematic block diagram of a rechargeable battery remaining amount display device according to an exemplary embodiment of the present invention. 4, a preferred embodiment of the present invention will be described. In addition, the secondary battery used in this embodiment will be described as an example of a nickel metal hydride battery (hereinafter referred to as a nickel hydrogen hydride battery).

Referring to FIG. 4, the secondary battery remaining amount display device of the present invention includes a charging unit 100, a battery 110, a DC / DC converter, a battery voltage detector 130, a battery temperature detector 140, and a load current detector 150. ), The microcomputer 160, the display unit 170, and the system unit 180.

First, the charging unit 100 rectifies and smoothes the commercial 100-220V AC power that changes over time, converts the DC power into a DC power source having a stable voltage level, and outputs a DC power source from an AC adapter. Is charged to charge the battery. At this time, in order to speed up the charging time of the battery, the size of the AC adapter should be increased. However, in such a case, the weight is heavy, so it is not suitable as a portable device. When constant current charging with a small wattage AC adapter, the charging time of the battery is long because the charging current is small.

Here, the charging unit needs a function to properly maintain the charging voltage or the charging current. Various charging circuits are used depending on the application, from the simple method of limiting the current to a single resistor to the method of managing the microcomputer with the conditions such as current, voltage, and temperature with great detail.

On the other hand, the charge in a short time with a large current becomes more severe the demand for overcharge prevention. In addition to precisely controlling voltage and current, it is necessary to stop charging by detecting a full charge state. Moreover, it is also important to fully charge similarly to preventing overcharge. Interrupting with insufficient charging shortens the battery's useful life. In general, if you charge with a large current and suddenly stop the current, it will not be fully charged. Once the full charge is detected, the charging amount can be further increased by lowering the current value or charging while changing the pulse current.

In the charging method, in more detail, the charging method is classified into a constant voltage charging method and a constant current charging method. The constant voltage charging method is a method of charging by applying a constant voltage higher than a nominal voltage (nominal voltage) of the battery at a predetermined ratio, and charging and discharging occur by comparing the charging voltage and the load. In other words, when the load is larger than that of the charging power source, the battery is discharged, and charging is usually performed. Here, the nominal voltage is a voltage displayed on the battery, and a value close to the discharge voltage in practical use is used.

The constant current charging method is a method of charging by applying a constant current to the battery regardless of the terminal voltage of the battery. The constant current charging method requires a constant current power supply for supplying a constant current, and by charging with a constant current, rapid charging is possible, it is possible to fully charge. However, overcharging beyond the full charge point inflicts more serious damage (eg, breakage) on the battery when overcharged in constant voltage charging.

The battery 110 is charged by a constant voltage and a constant current from the charging unit 100, and includes a dirt 111. The dummyster 111 is a semiconductor device having a resistance inversely proportional to temperature, and is a device for detecting the temperature of the battery 110.

The DC / DC converter 120 receives a DC voltage from the battery 110 and outputs a plurality of levels of DC voltages. That is, provide each load with the power they need.

The battery voltage detector 130 detects voltages of both terminals of the battery and provides a voltage signal Vd corresponding to the detected voltage to the microcomputer 160.

The battery temperature detector 140 includes a comparator for comparing the reference temperature and the detected temperature. In operation, the dummyster 111 detects the temperature of the battery 110 and provides a temperature signal Td corresponding to the detected temperature to the microcomputer 160. On the other hand, rapid charging causes a rapid temperature rise after full charge. At this time, it may add a role of sensing the temperature of the battery and stopping charging when the temperature reaches a predetermined temperature.

7 is a graph illustrating a change in battery voltage according to a temperature change of the battery 110. Referring to FIG. 7, graph 1 is a graph showing the voltage and the residual amount when the temperature of the battery 110 is 25 ° C., that is, the reference temperature (25 ° C.), and graph 2 shows that the temperature thereof is the reference value. It is a graph which shows the voltage and residual amount when it is higher than temperature, and graph 3 is a graph which shows the voltage and residual amount when its temperature is lower than the said reference temperature.

For example, if the voltage is 1.24V when the temperature is 25 ° C, the actual remaining amount is measured as 60% .However, when the temperature rises to graph 2, the remaining amount becomes higher than the voltage at the point B. It is measured that this is 80%. That is, when the temperature is higher than the reference temperature, the remaining amount is displayed higher than the actual remaining amount. On the contrary, when the temperature is lower than the reference temperature, the remaining amount is displayed lower than the actual remaining amount.

The load current detector 150 detects the amount of current discharged from the battery 110 and provides a load current signal Id corresponding to the detected discharge current (or 'load current') to the microcomputer 160. do. 9 is a graph showing the characteristics of the voltage change according to the magnitude of the discharge current. Referring to FIG. 9, the voltage of the battery 110 is lowered when using a load current 1C that is larger than when the system unit 180 is generally used, that is, when the magnitude of the discharge current is 0.5C. As the voltage of the battery 110 is lowered, the remaining amount displayed is lower than the actual remaining amount. On the contrary, when the magnitude of the discharge current is smaller than 0.5C (for example, 0.2C), the voltage of the battery 110 becomes high. As the voltage of the battery 110 increases, the remaining amount displayed is higher than the actual remaining amount. At this time, the current at the time of charging or discharging of the battery 110 is generally expressed as a multiple of the rated capacity (a reference value representing the capacity of the battery, 'C'). For example, the amount of discharge current is 0.5C means that it is discharged with the amount of current 0.5 times the rated capacity (C).

The microcomputer 160 receives the information signals Vd, Id, Td, and Tid of the battery 110 and outputs a corresponding remaining amount information display signal FG_S.

5 is a view for explaining a method of displaying the remaining amount of a secondary battery. Referring to FIG. 5, the microcomputer 160 receives a voltage signal Vd to calculate a corresponding residual amount, and receives a temperature information signal Td and a load current signal Id to correct a calculated battery residual value. do.

In more detail, when the temperature information signal Td from the battery temperature detector 140 is large, the microcomputer 160 may have a higher temperature than the reference temperature (25 ° C). In this case, since the terminal voltage of the battery 110 is increased, the remaining amount displayed is displayed in an increased amount than the actual remaining amount. Therefore, the microcomputer 160 reduces the residual value by a value corresponding to the deviation between the reference temperature and the detected temperature. On the contrary, when the detected temperature is lower than the reference temperature, the micom 160 reduces the residual value by the value corresponding to the deviation between the two temperatures. To increase.

In addition, the microcomputer 160 has a large load current signal Id from the load current detection unit 150, that is, when the detected load current amount is larger than the current (0.5C) at a normal load application (1C). As the terminal voltage of the battery 110 is reduced, the remaining amount displayed is displayed in a reduced amount than the actual remaining amount. Therefore, the microcomputer 160 increases the residual value by a value corresponding to the deviation between the current 0.5C and the detected load current value 1C when the general load is applied, and conversely, the detected load current is applied to the general load. When the current is smaller than the current, the remaining value is decreased by a value corresponding to the deviation of the two load currents.

In addition, the microcomputer 160 may be configured by adding a timer 161 for measuring the time left from the full charge of the battery 110 before the start of its discharge.

8 is a graph showing the variation of the battery voltage according to the standing time after full charge. Referring to FIG. 8, the microcomputer 160 corrects the remaining value by a value corresponding to the idle time information signal Ti from the timer 161. That is, as the length of time left from the full charge of the battery 110 to the start of its discharge is measured longer, the voltage of the battery 110 decreases, so that the remaining amount displayed is reduced than the actual remaining battery amount. . Accordingly, the microcomputer 160 increases the remaining value by a value corresponding to the leaving time, and conversely, the shortening time decreases the remaining value.

The display unit 170 is configured of an LCD and displays a remaining amount value corresponding to the remaining amount information display signal FG_S from the microcomputer 160.

6 is a flowchart illustrating the operation of the secondary battery remaining amount display device of the present invention. An embodiment of the present invention will be described with reference to FIG. 6.

The battery 110, the battery voltage detector 130, the battery temperature detector 140, the load current detector 150, the microcomputer 160, the display unit 170, and the system unit 180 may be provided. In the method for displaying, the battery voltage detector 130 detects voltages of both terminals of the battery 110 (S20) and outputs a voltage signal Vd corresponding to the detected voltage to the microcomputer 160. . The microcomputer 160 calculates a battery remaining value based on the voltage signal Vd (S21).

At this time, the battery temperature detector 140, the load current detector 150, and the timer 161 detects a remaining amount correction factor from the battery 110 (S22), respectively corresponding signals (Td, Id, And Tid) to the microcomputer 160. The microcomputer 160 stores the detected remaining amount correction factors (battery temperature, the magnitude of the load current, and the time left after full charge), respectively, by a predetermined reference value (for example, the temperature is 25 ° C. and the magnitude of the load current is 0.5C). Etc.) and if there is a difference from the reference value in step S23, i.e., if the remaining amount is lower than the actual remaining amount, or if the remaining amount is higher than the actual remaining amount, The displayed remaining amount is corrected as high or as low as a value corresponding to each difference (S24) and the battery remaining amount information display signal FG_S corresponding to the corrected value is generated.

The display unit 170 receives the remaining amount information display signal FG_S from step S24 and displays the remaining amount value (S25).

As described above, according to the present invention, when the voltage of the battery is detected and the remaining amount of the battery is displayed, the voltage variation according to the change of the load current, the voltage variation according to the temperature, and the idle time after full charge By calculating the voltage fluctuation by the microcomputer and correcting the battery remaining amount, more accurate battery remaining amount can be displayed.

Claims (8)

A portable computer device having a function of indicating the remaining voltage of a rechargeable battery; Means (130) for detecting a voltage of the battery (110) and generating a voltage signal (Vd) corresponding to the detected voltage; Means (140) for detecting a temperature of the battery (110) and generating a temperature signal (Td) corresponding to the detected temperature; Means (150) for detecting the amount of current flowing from the battery (110) to the loads and generating a current signal (Id) corresponding to the detected amount of current; The remaining battery information display signal corrected by calculating the remaining amount of the battery 110 by the voltage signal Vd and correcting the calculated remaining amount by the temperature signal Td and the load current signal Id ( Correction means (160) for outputting FG_S; And a means (170) for displaying remaining amount information corresponding to the remaining amount information indicating signal (FG_S). The method of claim 1, Means (100) for charging the battery (110); Means for measuring the neglected time from full charge of the battery 110 before the start of its discharge, and generating an idle time information signal Tid corresponding to the measured time, and adding the correction means And (160) correcting the calculated remaining amount by the idle time signal (Tid). The method of claim 1, The battery (110) is a battery level indicator of a portable computer system, characterized in that it comprises a dummyster (111) for sensing its surface temperature. In the method for displaying the remaining amount of the secondary battery, comprising a battery 110, voltage detection means 130, temperature detection means 140, load current detection means 150, correction means 160, Detecting a voltage of the battery 110 (S20); Calculating a residual amount of a battery based on the detected voltage (S21); Detecting battery residual correction factors causing inaccuracy of the battery residual value (S22); Determining whether correction of the calculated remaining amount is necessary based on the remaining amount of battery correction factors (S23); Correcting the residual amount deviation of the battery when operation correction is required (S24); And displaying (S25) the corrected remaining amount of battery. The method of claim 3, wherein The remaining battery level correction factor is a time remaining from the temperature, the amount of load current, the full charge of the battery. The method of claim 4, wherein In the step 24, when the detected temperature of the battery 110 is higher than the predetermined reference temperature, the remaining value is decreased by a value corresponding to the temperature deviation, and conversely, when the detected temperature is lower than the reference temperature, And displaying a remaining battery value by a corresponding value. The method of claim 4, wherein In step 24, if the detected load current is larger than the current when the load is applied, the remaining value is increased by a value corresponding to the load current deviation, and conversely, when the load current is smaller than the current when the load is applied, A remaining battery value display method of a portable computer system, characterized in that for reducing the residual value by a value corresponding to a current deviation. The method of claim 4, wherein In step 24, the remaining value from the full charge of the battery to the start of its discharge is measured longer, and the remaining value is increased by a value corresponding to the leaving time, and conversely, the remaining value is shortened as the leaving time is short. A battery level display method of a portable computer system, characterized in that the.