KR19980065907A - Battery fast charge control device - Google Patents

Abstract

The present invention relates to a fast charging control device for a battery, and in particular, a sample and hold circuit unit for sampling the charging voltage of the battery; A first analog-digital converter for converting the analog signal of the charging voltage into a digital signal; A first digital-analog converter converting the digital signal into an analog signal; A second digital-analog converter converting the digital signal transmitted from the first analog-digital converter into an analog signal during a next sampling time interval; An amplifying unit configured to receive an analog signal of each of the first and second digital-to-analog converters and amplify and output the first derivative of the charging voltage; A second analog-to-digital converter for converting the analog signal output from the amplifier into a digital signal; A third digital-analog converter for converting the digital signal converted by the second analog-digital converter into an analog signal; A fourth digital-analog converter converting the digital signal transmitted from the second analog-digital converter into an analog signal during a next sampling time interval; And a comparator configured to receive respective analog signals from the third and fourth digital-analog converters, compare the respective analog signals, and output a comparison signal in the form of a second derivative of the charging voltage.

Description

Battery fast charge control device

The present invention relates to a fast charge control device, and more particularly, to a fast charge control device capable of preventing overcharging of a battery by sampling a battery charge voltage, detecting an inflection point of a charge voltage change curve, and controlling charging of the battery. will be.

In general, in a system for rapidly charging a NiCd battery or a NiMH battery, when overcharging occurs during charging, the battery not only consumes energy but also significantly affects the damage and life of the battery.

Therefore, it is necessary to detect the end point of charge of the battery early, and accordingly predict the overcharge of the battery so that the control system controls the charging of the battery.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rapid charge control device capable of preventing overcharging of a battery by sampling a battery charging voltage, detecting an inflection point of a charging voltage change curve, and controlling charging of the battery. There is.

In order to achieve the above object, the apparatus of the present invention comprises a sample and hold circuit unit for sampling the charge voltage of the battery in synchronization with the first clock signal; A first analog-digital converter for converting the analog signal of the charging voltage into a digital signal; A first digital-analog converter converting the digital signal into an analog signal; A second digital-analog converter converting the digital signal transmitted from the first analog-digital converter into an analog signal and outputting the analog signal during a next sampling time interval; An amplifier configured to receive a current analog signal from the first digital-analog converter and a previous analog signal from the second digital-analog converter, and output an amplified analog signal having a first derivative of the charging voltage; A second analog-digital converter for converting the analog signal output from the amplifier into a digital signal; A third digital-analog converter for converting the digital signal converted by the second analog-digital converter into an analog signal; A fourth digital-analog converter which converts the digital signal transmitted from the second analog-digital converter into an analog signal during a next sampling time interval and outputs the analog signal; And a comparator configured to receive a current analog signal of the third digital-analog converter and a previous analog signal of the fourth digital-analog converter and output a comparison signal in the form of a second derivative of the charging voltage. It is done.

1 is a block diagram illustrating a rapid charge control device according to the present invention.

2 is a block diagram illustrating a transmission path between an analog-digital converter and a digital-analog converter according to the present invention.

3 is a graph showing a charging voltage curve of a battery.

4 is a timing diagram showing a clock signal applied to the present invention.

5 is a graph for explaining the voltage change according to the inflection point of the charging voltage curve

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a rapid charge control apparatus according to the present invention, and as shown in FIG. 1, the charging voltage of the battery in synchronization with the current supply unit 10, the battery B, and the first clock signal 11. A sample-and-hold circuit section 20 for sampling the signal, a first analog-to-digital converter 40 for converting the analog signal of the charging voltage into a digital signal, and a first digital-to-analog converter for converting the digital signal into an analog signal. 60, a second digital-to-analog converter 80 that receives a digital signal from the first analog-to-digital converter 40 during the next sampling period, converts the analog signal into an analog signal, and outputs the analog signal; A) to receive and amplify the current analog signal and the previous analog signal from the second digital-to-analog converter 80 to output an analog signal having a first derivative of the charging voltage. The digital signal converted by the unit 100, the second analog-to-digital converter 120 for converting the analog signal output from the amplifier 100 into a digital signal, and the digital signal converted by the second analog-to-digital converter 120 are analog. A third digital-to-analog converter 140 for converting into a signal, and a fourth digital-to-analog converter 160 for receiving a digital signal from the second analog-to-digital converter 120 during the next sampling time, converting the signal into an analog signal, and outputting the converted analog signal; And receiving and comparing the current analog signal of the third digital-analog converter 140 and the previous analog signal of the fourth digital-analog converter 160 to output a second differential form of the charging voltage. Comparing unit 180 is included.

As shown in FIG. 3, a first transmission path between the first analog-to-digital converter 40 and the first and second digital-to-analog converters 60 and 80 is synchronized with the second clock signal 12. A plurality of flip-flops D0 to Dn for latching the digital signal converted by the first analog-to-digital converter 40, and transmitting the latched digital signal to the first digital-analog converter 60, and the third clock signal ( In response to 13), a plurality of flip-flops F1 to receive the digital signals from the plurality of flip-flops D0 to Dn and latch them, and transmit the latched digital signals to the second digital-analog converter 80. Fn).

The second transmission path between the second analog-to-digital converter 120 and the third and fourth digital-to-analog converters 140 and 160 is the same as that of the first transmission path.

The amplifier 100 is composed of a transconductance amplifier 102 and a load resistor (R).

The operation of the apparatus of the present invention configured as described above will be described with reference to the graph diagrams of the charging voltage curves of FIGS. 3 and 5 and the clock signal waveform diagram of FIG. 4.

In FIG. 1, when the current is charged in the battery B by the current supply unit 10, that is, the current driver, the charging voltage of the battery increases. As shown in FIG. 3, when the charging voltage curve of the battery B suddenly increases and reaches a certain point, the battery does not charge any more. Here, the charging voltage is changed from the increase of the charging voltage to the decrease at the inflation point (A). Therefore, the present invention makes it possible to predict the state of charge of the battery by detecting this inflection point A.

The sample and hold circuit section 20 samples the charging voltage in a predetermined time interval in synchronization with the rising edge of the first clock signal 11 at time T1 shown in FIG.

Referring to FIG. 2, the sampled analog signal is converted into a digital signal in the first analog-to-digital converter 40 and then transmitted to the first digital-analog converter 60, and the second in the next sampling period T3. In synchronization with the clock signal 12, the plurality of flip-flops D0 to Dn latch the digital signal transmitted to the first digital-analog converter 60 and transmit it to the second digital-analog converter 80.

Subsequently, when the third clock signal 13 is activated at time T4, the digital signals latched to the plurality of flip-flops D0 to Dn are latched to the plurality of flip-flops F1 to Fn, and the second digital-to-analog converter ( 80).

Meanwhile, the plurality of flip-flops D0 to Dn latch new digital signals and transmit them to the first digital-analog converter 60.

The amplifier 100 amplifies and outputs each analog signal converted by the first digital-analog converter 60 and the second digital-analog converter 80 to the second analog-to-digital converter 120. Here, the amplifier 100 outputs an analog signal of the first derivative of the battery charging voltage.

The second analog-to-digital converter 120 converts the analog signal provided from the amplifier 100 back to a digital signal and transmits the analog signal to the third digital-analog converter 140 and the fourth digital-analog converter 160. This is the same as the transmission process of the first analog-to-digital converter 40 described above.

The comparator 180 compares the two analog signals converted by the third digital-analog converter 140 and the fourth digital-analog converter 160, and outputs a comparison signal, and the controller (not shown) by the comparison signal. By controlling the current supply unit 10 to narrow the sampling time interval and reduce the amount of current supply before the battery reaches full charge, it is possible to prevent damage to the battery due to overcharging.

Hereinafter, the charging voltage curve will be described in more detail with reference to FIG. 5. When the inflection point occurs at the sampling time Tn + 1, multiplying the amount of change in the charging voltage for the sampling time interval before and after the inflection point,

In the sampling time interval before the inflection point, the area An of ΔT × ΔVn / 2, the area An + 1 of ΔT × ΔVn + 1/2 and the area An + 2 of ΔT × ΔVn + 2/2 after the inflection point, respectively. You can get it. Here, the areas An, An + 1, An + 2 change from increasing to decreasing from the inflection point.

If the area An + 1 of the sampling time interval Tn + 1 is the output of the third digital-analog converter 140, the output of the fourth digital-analog converter 160 is in the previous sampling time interval Tn. Area (An + 1). Then, the comparator 180 generates a high output.

On the other hand, the area An + 2 of the sampling time interval Tn + 2 is the output of the third digital-analog converter 140 and the output of the fourth digital-analog converter 160 is the area An + 1. If, the comparison unit 180 is inverted to the output of the row.

Accordingly, the charging of the battery is controlled by controlling the current supply unit 10 according to the output signal of the comparator 180.

Therefore, as described above, the present invention detects the inclination of the battery charging voltage, determines the inflection point from the inclination, and controls the charging of the battery according to the generation of the inflection point, thereby predicting full charge during rapid charging of the battery, and overcharging There is an effect that can be prevented in advance.

Claims (1)

A sample and hold circuit unit configured to sample the charging voltage of the battery in synchronization with the first clock signal; A first analog-digital converter for converting the analog signal of the charging voltage into a digital signal; A first digital-analog converter converting the digital signal into an analog signal; A second digital-analog converter converting the digital signal transmitted from the first analog-digital converter into an analog signal and outputting the analog signal during a next sampling time interval; An amplifier configured to receive a current analog signal from the first digital-analog converter and a previous analog signal from the second digital-analog converter, and output an amplified analog signal having a first derivative of the charging voltage; A second analog-digital converter for converting the analog signal output from the amplifier into a digital signal; A third digital-analog converter for converting the digital signal converted by the second analog-digital converter into an analog signal; A fourth digital-analog converter which converts the digital signal transmitted from the second analog-digital converter into an analog signal during a next sampling time interval and outputs the analog signal; And a comparator configured to receive a current analog signal of the third digital-analog converter and a previous analog signal of the fourth digital-analog converter and output a comparison signal in the form of a second derivative of the charging voltage. Battery fast charge control circuit.