KR920005190B1 - Method and charging circuit of battery - Google Patents

Abstract

The circuit includes a charge selecting section (40) for generating quick/normal charge mode signals by the selection of the user. A control section (50) enables first and second control signals, and disables the first and second control signals upon detecting an over-charge signal. A current adjusting section (60) enables a quick charging means upon receiving the second control signals, and supplies a quick charging dc power to a battery pack. An over-charge detecting section (80) compares the voltage of the charged battery pack with a reference voltage to supply an over-charge detection signal upon detecting an over-charge to the control section (60).

Description

Charging Circuit and Method of Rechargeable Battery

1 is a conventional charging circuit diagram.

2 is a block diagram of a battery charging circuit according to the present invention.

3 is a concrete circuit diagram of FIG.

4 is a charging timing chart of a battery according to the present invention.

5 is a charging flowchart of a battery according to the present invention.

* Explanation of symbols for main parts of the drawings

10: adapter 20: regulator

30: battery pack 40: charge selector

50: control unit 60: current control unit

70: reference voltage generator 80: overcharge detector

The present invention relates to a charging circuit and a method of a rechargeable battery, and more particularly, to a circuit and a method capable of selecting a charging time as necessary and at the same time to prevent overcharging.

1 is a charging circuit diagram of a conventional rechargeable battery. The battery 3, an adapter 1 for rectifying AC power with a DC power supply, and a constant current are charged in the battery 3. And a load 4 for maintaining a constant DC voltage in the adapter 1.

Looking at the conventional battery charging process having the configuration as described above, the adapter 1 rectifies the AC power of 110V / 220V to a constant DC power supply, this rectified voltage is applied to the load (4) appears at point A. At this time, when the contacts T1 and T4 and T3 and T6 are connected to charge the battery 3, the voltage at the point A flows to the charging current circuit 2 so that the battery 3 is charged. In this case, the charging current is fixed and charged by either normal charging or quick charging.

However, the conventional charging method as described above is fixed to either normal charging or rapid charging, and thus the charging current cannot be adjusted, and thus the charging time cannot be changed, and there is no preventive measures against overcharging, and thus the battery life due to overcharging. There was a problem that caused the shortening of.

Accordingly, an object of the present invention is to provide a circuit and a method for controlling a charging time when charging a rechargeable battery.

Still another object of the present invention is to provide a circuit and a method capable of prolonging battery life by preventing overcharge when charging a rechargeable battery.

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

2 is a block diagram of the present invention, the adapter 10 for rectifying AC power to a predetermined level of DC power according to the load, and receives the output of the adapter 10, the received DC power is a constant voltage The battery pack (30), the charge selector (40) for generating a mode selection signal according to rapid or normal charging, and the P4 terminal. 30, P5 terminal is connected to the charge selector 40, the logic state of the mode selection signal received by the P5 terminal when the connection signal of the battery pack 30 is received from the P4 terminal Analyzing, enabling the P2 terminal in the fast charging mode and enabling the P1 terminal in the normal charging mode, and the microcomputer 50 for disabling the P1 terminal and the P2 terminal when receiving an overcharge signal to the P3 terminal, and a quick charging means. And a normal charging means, It is connected between the regulator 20 and the battery pack 30 and receives the output of the microcomputer 50 as a control signal, when the enable signal is generated to the P2 terminal to switch the rapid charging means and to enable the P1 terminal When the signal is generated, the normal charging means is switched to receive the output of the current adjusting unit 60 and the regulator 20 for supplying the charging current corresponding to the designated mode to the battery pack 30, and the received power is divided. The reference voltage generator 70 for generating a reference voltage for determining whether the battery pack 30 is overcharged, and the microcomputer 50 when the battery pack 30 is overcharged by comparing the state of charge of the battery pack 30 with the reference voltage. The overcharge detection unit 80 outputs an overcharge detection signal to the P9 terminal.

In the configuration of FIG. 2, the microcomputer 50 performs a function of a controller for controlling the overall operation of the charging circuit according to the present invention. In addition, a signal for enabling the P1 terminal in the normal charging mode becomes a first control signal, and a signal for enabling the P2 terminal in the quick charge mode becomes a second control signal.

3 is a diagram illustrating a specific embodiment of FIG. 2, wherein the regulator 20 includes a diode D1, a capacitor C1-C3, a resistor R1, a zener diode ZD1, and a transistor Q1. Battery pack 30 is composed of a resistor (R12, R13), a diode (D3), a transistor (Q4) and a battery (BT), the charge selector 40 is made of a switch, the current control unit 60 ) Is composed of resistors R2-R6, transistors Q2-Q3, and diodes D2, and the reference voltage generator 70 includes a constant voltage source 71, resistors R7-R8, variable resistor VR1. And a zener diode (ZD2), and the overcharge detection unit (80) is composed of resistors (R9-R12) and comparators (CMP).

4 is a waveform diagram showing a state of charge of a battery charged at 1.2 V and 500 mA at a temperature of 20 ° C., where 4A is a charging waveform diagram of the battery BT at the time of rapid charging, and 4B is a normal charging state. Is a charging waveform diagram of the battery BT.

5 is a flow chart of the charging of the battery BT according to the present invention, a process of checking whether a battery pack is connected to recognize a start of charging when the battery pack is connected, and a process of checking a charging selection mode when the start of charging is recognized. And enabling the rapid charging means in the quick charge mode during the mode inspection process to supply the rapid charging current to the battery pack, and enabling the normal charging means in the normal charging mode during the mode inspection process. Supplying a normal charging current to the battery pack, and discharging the charging means when the overcharge detection signal of the battery pack is received in the charging process to terminate the charging.

Based on the above configuration, the present invention will be described with reference to FIGS. 2, 3, 4, and 5. FIG.

First, when the battery pack 30 is connected to the charging circuit of the present invention, the T1 terminal, the T4 terminal, the T2 terminal, the T5 terminal, the T3 terminal, and the T6 terminal are in contact with each other, and thus, the transistor Q4 of the battery pack 30. ) Is turned on to apply a "low" signal to the P4 terminal of the microcomputer 50. Therefore, the microcomputer 50 detects the charge up (charge ON) by recognizing that the battery pack 30 is in contact with the charger. At this time, the time for detecting the charging up of the microcomputer 50 takes into account the delay time when the high voltage applied to the collector of the transistor Q1 is converted into the voltage level of the battery BT and the mechanical chattering time of the terminal. It is about 1 second. At this time, the regulator 20 inputs the DC power of the adapter 10 to regulate the voltage to a predetermined voltage level. The zener diode ZD1 takes about 8.5V to the collector terminal of the transistor Q1. So that it is adjusted.

When the "low" signal is received through the P4 terminal to detect the charging increase in the microcomputer 50, that is, when the battery pack 30 is recognized as being loaded on the charger, the microcomputer 50 receives the P5 terminal. Through the sensing of the fast charging or normal charging mode signal selected by the switch of the charging selection unit 40 to determine the type of charging. In this case, when the switch of the charging selector 40 is "on", it is assumed that the normal charging mode is set, the microcomputer 50 recognizes the selection of the fast charging mode when the "high" signal is received to the P5 terminal. When the P5 terminal is in the "low" state, it is recognized as the selection of the normal charging mode.

First, the operation process in the fast charge mode will be described.

In the quick charge mode, the microcomputer 50 receives a "high" signal through the P5 terminal, in which case the microcomputer 50 generates a "high" signal through the P2 terminal and a low signal through the P1 terminal. "Generates the signal. Then, the transistor Q3 of the current controller 60 is turned on and the transistor Q3 is turned off. If the values of the resistors R2-R4 are set to R2 > R3 > R4, the configurations of the resistors R4 and Q3 serve as rapid charging means, and the resistors R3 and Q2 are normally charged. Means, and resistor R2 is a trickle charging means. Therefore, when the transistor Q3 is turned on, a rapid charging current path is formed through the resistor R4 and the transistor Q3 so that a large current is applied to the battery BT. Here, the rapid charging is a 0.3C current flows to the battery BT, the normal charging is a 0.1C current flows to the battery BT. In this case, "C" refers to the current required to charge the standard capacity for 1 hour.

Therefore, in the fast charging mode, the transistor Q3 is turned on, so that the fast charging current I3 flowing through the resistor R3 becomes 0.3C current, and this I3 current is discharged through the diode D2 and the terminals T1 and T4. The fast charging operation is performed at BT.

When the charging mode is performed as described above, it should be possible to test whether the battery BT is being overcharged by analyzing the state of charge of the battery BT. To this end, the charging voltage of the battery BT is applied as a comparison voltage of the comparator CMP, where the resistors R9 are formed at the resistors R9 and R10 that generate the comparison voltage of the comparator CMP for detecting the presence of overcharge. Set the resistance value of to very large and adjust so that a fine current flows. At this time, the voltage charged in the battery BT is gradually increased over time, and thus the divided voltages of the resistors R9 and R10 applied as the comparison voltages of the comparator CMP are also gradually increased. The reference voltage of the comparator CMP divides a constant DC voltage through the constant voltage source 71 and the zener diode ZD2 of 5V through the resistor R8 and the variable resistor VR1 to thereby divide the non-inverting terminal of the comparator CMP. Is applied. In this case, the reference voltage is set to be switched when the charging voltage of the battery BT is generated to be higher than 4.3V (1.43VX3). If the charging voltage of the battery BT is overcharged as at the point S1 of 4A during the rapid charging as described above, a voltage of 4.3 V is generated. In this case, the comparator CMP generates a "low" signal indicating an overcharge state and applies it to the P3 terminal of the microcomputer 50. At this time, the microcomputer 50 turns off the transistors Q2 and Q3 of the current control unit 60 by generating a "low" signal indicating that the signal received through the P3 terminal indicates an overvoltage detection state. Therefore, the passage of 13 currents, which are fast charging flows, is blocked, and only a trickle current path through the resistor R2 is formed so that the I1 current is supplied to the battery BT. The trickle current I1 current is 0.033C, which does not affect the life of the battery BT at all.

Second, look at the case of normal charging.

In the normal charging mode, the microcomputer 50 receives a "low" signal through the P5 terminal. As a result, the microcomputer 50 outputs a "high" signal to perform the normal charging mode and generates a "low" signal through the P2 terminal. Therefore, the path of the normal charging current is formed so that the normal charging current I2 of 0.1C is applied to the battery BT, thereby the battery BT performs the normal charging operation.

At this time, the microcomputer 50 checks the output of the comparator CMP, and when the comparator CMP outputs a "high" signal, the microcomputer 50 considers that it is not in an overcharge state and continuously controls to form a normal charging current path. When the output of the comparator (CMP) changes to the "low" signal as in S2 of 4B), it recognizes it through the P3 terminal and outputs the "low" signal to the P1 and P2 terminals, considering it as an overcharge state. Therefore, since the passage of I2 is blocked because the passage of I2 is blocked, the passage of I1 performing trickle charging is maintained and applied to the battery BT.

In order to generate I3, I2, and I1 currents for performing rapid charging, normal charging, and trickle charging as described above, the resistance value is set to R2> R3> R4. When the resistance value is obtained, the following <1>, < 2>, <3> is the same as the formula.

5 is a flowchart of controlling the microcomputer 50 during charging. First, the microcomputer 50 checks whether the battery pack 30 is placed on the charging circuit of the present invention through a P4 terminal. ) Is received, a "low" signal is received at the P4 terminal. Therefore, when the microcomputer 50 receives a "low" signal through the P4 terminal, the microcomputer 50 recognizes the charging signal as a charging up signal connecting the battery BT to a charging circuit in order to charge the battery BT in step (A). In the step (B) is charged by analyzing the state of the switch of the charge selection unit 40 through the P5 terminal. That is, the logic state of the P5 terminal is determined by the switch of the charging selector 40. In the fast charging mode, a "high" signal is received, and in the normal charging mode, a "low" signal is received.

At this time, when the "high" signal is received at the P5 terminal, the microcomputer 50 considers the fast charging mode in step (B) and generates a "low" signal at the P1 terminal and a "high" signal at the P2 terminal. Then, the transistor Q3 is turned on to form a passage of the rapid charging current I3 through the resistor R4 and the transistor Q3 which are fast charging means, and the charging current I3 is applied to the battery BT. Therefore, in step (C), the battery BT performs a fast charging function, and the microcomputer 50 checks the state of the P3 terminal in step (D) to check for overcharge. At this time, when the comparator CMP outputs a "high" signal to the P3 terminal, it continues to form a passage of I3 to rapidly charge the battery BT, but when the comparator CMP outputs a "low" signal ( Proceed to Step E) and output a "low" signal to the P1 terminal to control to form only the I1 passage which is the trickle charging current.

In addition, when it is determined in the normal charging mode in the step (B), the microcomputer 50 outputs a "high" signal to the P1 terminal and a "low" signal to the P2 terminal in the (F) step is a normal charging current A passage of I2 is formed and controlled to be supplied to the battery BT. After that, in step (G), the output state of the comparator (CMP) is analyzed through the P3 terminal, and when overcharge is detected, a "low" signal is output to the P1 and P2 terminals in the (H) step to pass the I1 current, the trickle charging current. Form a bay.

As described above, when charging the rechargeable battery, the charging time can be adjusted so that the charging type can be selected so as to rapidly or normally charge the rechargeable battery, and the life of the battery can be extended by adding an overcharge preventing circuit.

Claims (2)

A battery pack charging circuit having a rechargeable battery, the battery pack charging circuit comprising: means for rectifying AC power to generate a predetermined level of DC power, a charging selector for generating a fast / normal charging mode signal by a user's selection; It is connected to the battery pack and the charge selector, and receives the mode signal of the charge selector when detecting the battery pack connection, enable the first control signal in the normal charging mode and enable the second control signal in the fast charging mode And a control unit for disabling the first and second control signals upon reception of an overcharge detection signal, a normal charging means and a rapid charging means, connected between the DC power supply and the battery pack, and the first control signal. Receiver The normal charging means is enabled to turn the DC power supply at the normal charge level into the battery pack red, and the second control signal receiver is enabled. For example, a current control unit for applying a DC power of a fast charging level to the battery pack, and receives a predetermined divided signal of the DC power supply as a reference voltage, and receives the charging voltage of the battery pack as a comparison voltage, and compares the two voltages And an overcharge detector configured to output an overcharge detection signal to the controller when the charge voltage is greater than the reference voltage. In a charging method of a battery pack having a charge control unit having a rapid charging means and a normal charging means, and a rechargeable battery, the process of recognizing the start of charging when the battery pack is connected by checking the connection of the battery pack and In the process of checking the charging selection mode at the start of the charging, and in the mode checking process during the fast charging mode during the fast charging means to supply a fast charging current to the battery pack, and in the mode checking process In the normal charging mode, enabling the normal charging means to supply a normal charging current to the battery pack, and disabling the charging means when the overcharge detection signal of the battery pack is received in the charging process to terminate charging. Charging method of a rechargeable battery, characterized in that consisting of.

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