KR19990030995U - Nickel-Hydrogen Battery Pack Protection Circuit - Google Patents

Abstract

The present invention relates to a nickel-hydrogen battery pack protection circuit that solves the unchargeable problem that occurs when charging a nickel-hydrogen battery pack with a lithium-ion charger and prevents the battery from being destroyed due to overcharging. The present invention and the constant voltage unit for making a constant voltage voltage supplied when the battery pack and the charger; A controller for controlling charging and discharging by determining whether the battery pack is connected to a charger; A charging control unit which supplies the power supplied through the connector to the charging power; A boosting unit for boosting a voltage required for charging the nickel-hydrogen battery; A temperature sensing unit configured to detect a temperature change of the battery as a voltage and determine whether to overcharge the control unit; In the nickel-hydrogen battery charging circuit using a lithium-ion charger composed of a discharge control unit for supplying the voltage charged in the nickel-hydrogen battery pack to the mobile phone under the control of the controller, detecting the voltage of the nickel-hydrogen battery pack A battery voltage sensing unit configured to input the control unit to the control unit; When the nickel-hydrogen battery pack is fully charged, the predetermined voltage (approximately 0.6V) is dropped to prevent the charger from recognizing the full charge and the microcomputer in the controller tracks the charging voltage during charging to fully charge the nickel-hydrogen cell. An additional diode is installed to detect and fully charge -dV.

Description

Nickel-Hydrogen Battery Pack Protection Circuit

The present invention relates to a battery pack protection circuit of a mobile phone, and more specifically, to solve the unchargeable problem that occurs when charging a nickel-hydrogen battery pack with a lithium-ion charger, and to prevent destruction of the battery due to overcharging. It relates to a nickel-hydrogen battery pack protection circuit.

In general, a portable telephone (hereinafter referred to as a mobile phone) is mainly supplied with power by a battery that is separately mounted. As such, a lithium-ion battery is commonly used as a battery for supplying power to the mobile phone.

However, when a battery pack is made using a nickel-hydrogen battery, which is cheaper than the lithium-ion battery and has a superior safety and lifespan, the characteristics of the lithium-ion battery and the nickel-hydrogen battery are unique. Due to the car, there was a problem in that it is impossible to charge in a charger made to charge only a lithium-ion battery pack.

For example, in case of lithium-ion battery, if the supply voltage from the charger is less than 8.4V for full charge, the input voltage of about 9V is required in case of nickel-hydrogen. In the case of lithium-ion, constant voltage charging should be performed after constant current charging. However, nickel-hydrogen takes constant current charging. In the case of lithium-ion, lithium-ion is determined as the lower limit of charging current, but nickel-hydrogen is charged. There is a problem of monitoring the change of the input voltage at the time and recognizing it as full charge when this voltage falls below a maximum voltage (-dV).

Due to this phenomenon, the user must use only a charger suitable for charging the corresponding battery, and thus there are limitations in various aspects.

The present invention is proposed to solve the above problems of the prior art,

The object of the present invention is to provide a nickel-hydrogen battery pack protection circuit that can solve the unchargeable problem that occurs when charging the nickel-hydrogen battery pack with a lithium-ion charger.

Another object of the present invention is to provide a nickel-hydrogen battery pack protection circuit to prevent destruction of the battery due to overcharging that occurs when charging the nickel-hydrogen battery pack with a lithium-ion charger.

Technical means for achieving the objects of the present invention, the constant voltage unit for supplying the drive voltage to the microcomputer in the control unit to make a voltage supplied when the battery pack and the charger connected;

It is driven by the voltage supplied from the constant voltage unit to control the charging control unit by determining whether the connection to the charger by the output voltage of the terminal indicating that the charger is connected to the charger of the battery pack of the battery pack, the battery temperature sensing signal and battery A controller for controlling charging and discharging according to the voltage of the controller;

A charging control unit for supplying power supplied through the connector to the charging power according to the charging control of the controller;

A boosting unit for boosting the voltage supplied from the charging control unit to a voltage required for charging the nickel-hydrogen battery so that a constant current flows and is charged in the nickel-hydrogen cell;

A temperature sensing unit comprising a resistor and a thermistor for dividing the output voltage of the constant voltage unit so as to detect a temperature change of the battery as a voltage and determine whether to overcharge the control unit;

In the nickel-hydrogen battery charging circuit using a lithium-ion charger composed of a discharge control unit for supplying a voltage charged in the nickel-hydrogen battery pack to the mobile phone under the control of the controller,

A battery voltage detector for detecting a voltage of the nickel-hydrogen battery pack and inputting it to a controller;

When the nickel-hydrogen battery pack is fully charged, the predetermined voltage (approximately 0.6V) is dropped to prevent the charger from recognizing the full charge and the microcomputer in the controller tracks the charging voltage during charging to fully charge the nickel-hydrogen cell. This can be achieved by installing a diode to detect and fully charge -dV, which is a full detection method.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention in detail as follows.

1 is a block diagram of a nickel-hydrogen battery pack protection circuit according to the present invention.

Explanation of symbols for the main parts of the drawings

1 control unit 2 charge control unit

3: boosting unit 4: temperature sensing unit

5: battery voltage detection unit 6: discharge control unit

7: constant voltage unit 8: connector

1 is a block diagram of a nickel-hydrogen battery pack protection circuit according to the present invention.

Here, reference numeral 8 is a connector connecting the battery pack BATT and the charger.

In addition, reference numeral 7 is composed of several resistors (R8, R10, R19, R20, R22, R23, R90), constant voltage regulator (U2), transistors (Q3, Q10), and capacitor (C2). When the BATT is connected and a predetermined voltage is supplied to the pin IDR of the connector 8, the battery voltage is made to be a constant voltage using the constant voltage, and the battery voltage is supplied to the microcomputer U1 in the controller 1 as a driving power.

Further, reference numeral 1 is composed of resistors R9 and R91, a microcomputer U1, and a capacitor C6, and is driven by a voltage supplied from the constant voltage unit 7, and at the same time an input terminal (7) from the constant voltage unit 7 When the high signal is inputted to the IDR-IN), the battery pack (BATT) recognizes that it is connected to the connection terminal of the charger, and controls the charging and discharging according to the temperature detection signal of the battery pack (BATT) and the voltage of the battery, as well as the output. The controller outputs a low signal through the terminal IDR-OUT to recognize that the charger is continuously connected to the battery.

Reference numeral 2 is composed of several resistors R1, R16, R21, and R25, a transistor Q1, and a capacitor C4, and is output from the output terminal CHG ON of the microcomputer U1 in the controller 1. The charging control unit for supplying the power supplied through the connector 8 to the charging power in accordance with the charging control signal.

Further, reference numeral 3 is composed of several resistors R5, R11, R18, and R26, a constant voltage integrated circuit U3, a coil L1, a capacitor C5 and C8, and a Schottky diode D2 to charge the battery. The booster is a booster for boosting the voltage supplied from the controller 2 to the charge voltage required by the nickel-hydrogen battery pack BATT so that a constant current flows in the nickel-hydrogen pack and is charged. It is composed of a resistor (R6) and thermistor (RT1) for dividing the output voltage of 7) is a temperature sensing unit for detecting the temperature change of the battery as a voltage to determine whether or not overcharge in the control unit (1).

Then, when the nickel-hydrogen battery pack is fully charged, the voltage drop is about 0.6V so that the charger cannot recognize the full charge, and the microcomputer u1 in the control unit 1 tracks the charging voltage when charging the nickel. -It is a diode to detect and fully charge -dV, a full charge detection method of hydrogen cells.

In addition, reference numeral 5 is composed of several resistors (R13-R15), a capacitor (C3) and a diode (D3) to detect the voltage of the nickel-hydrogen battery pack (BATT) to input to the controller 1 A voltage sensing unit, and reference numeral 6 is composed of several resistors R7, R12, and R24, a transistor Q5, and a field effect transistor Q4, according to the discharge control signal output from the control unit 1, Discharge control unit for discharging by supplying the voltage charged in the hydrogen battery pack (BATT) to the mobile phone.

The nickel-hydrogen battery pack protection circuit according to the present invention configured as described above is controlled in two aspects, namely, charge control and discharge control.

First, when the battery pack BATT is connected to the charger, a voltage of about 4 V is applied to the pin IDR of the connector 8, and the voltage is applied to the transistor Q3, through the resistor R10 of the constant voltage unit 8. Since the transistors Q3 and Q10 are electrically connected to each other, the battery pack batt voltage is converted into a voltage of 5V through the constant voltage regulator U2, and the converted voltage is converted into the microcomputer U1 in the controller 1. The microcomputer starts to operate.

At this time, the microcomputer U1 in the control unit 1 recognizes that a high signal is input through the input terminal IDR-IN connected to the output terminal of the constant voltage unit 7, thereby indicating that the battery pack BATT is connected to the charger. The controller outputs a low to the constant voltage unit 7 through its output terminal IDR-OUT to recognize that the charger is continuously connected to the battery.

The connector 9 is a 4-pin connector having a CHARGE terminal, a SENSE terminal, an ID-R terminal, and a GND terminal for charging.

In addition, the microcomputer U1 outputs a low signal through the output terminal DCHG ON, thereby sequentially interrupting the driving of the transistor Q5 and the field effect transistor Q4 of the discharge control unit 6, so that the battery pack Batt After the voltage drops about 0.6V through the diode D1, it is applied to the pin (CHARGE terminal) of the connector 8, which is a nickel-hydrogen battery pack when the voltage of the nickel-hydrogen battery cell is fully charged (about 9V). Since it is about 0.6V higher, it is intended to prevent the charger from being mistaken for full charge.

That is, since the full charge voltage of the lithium-ion battery pack is 8.4V and the full charge voltage of the nickel-hydrogen battery pack is about 9V, the battery voltage is blocked by blocking the field effect transistor Q4 of the discharge control unit 6 during charging. A voltage drop of 0.6V is generated through this diode (D1) to prevent the charger from recognizing full charge, and microcomputer (U1) tracks the charge voltage during charging to detect -dV, a full charge detection method of nickel-hydrogen. It can be fully charged.

In this case, since the charging voltage output from the charger is supplied to the battery again through the field effect transistor Q4 of the discharge control unit 6 through the CHG terminal of the connector 8, the battery pack is charged. While continuing, the microcomputer U1 can keep track of the voltage of the battery.

When the battery voltage connected to the connector 8 is relatively low, the microcomputer U1 conducts the field effect transistor Q4 of the discharge control unit 6 so that the current supplied by the charger does not pass through the booster unit 3. The charging efficiency can be increased by charging through the field effect transistor Q4, and since the charger cannot supply more than 8.4V of the charging voltage, when the battery voltage is 8V or more, the transistors Q2, Q1) is conducted to be charged using the booster 3.

In addition, if the battery is over-discharged and the microcomputer U1 does not operate normally, ground the resistors R22 and R90 to allow the charger to recognize the battery as a small capacity battery and charge the battery with low current. In this case, by outputting a low signal to the output terminal (IDR OUT) so that only the resistor (R22) is grounded, the charger recognizes it as a large capacity battery and charges the battery with a large current, thereby greatly reducing the charging time.

On the other hand, the microcomputer U1 outputs a high signal for about 1 second through its output terminal DCHG ST to sense the voltage of the battery pack BATT. The output terminal DCHG of the microcomputer U1 is as described above. When the high signal is output from the ST, the voltage divided by the voltage of the battery pack according to the voltage dividing ratio of the resistors R15, R13, and R14 is charged to the capacitor C3.

When the charging of the capacitor C3 in the battery voltage detecting unit 5 is completed, the microcomputer U1 outputs a low signal through its output terminal DCHG ST to discharge the charge charged in the capacitor C3. Be sure to

That is, when the battery voltage is charged to the capacitor C3, the high signal is output from the output terminal DCHG ST of the microcomputer U1, so that the diode D3 is connected in the reverse direction so that the battery voltage is connected to the resistors R15, R13, and R14. Since only the partial pressure is charged by the voltage, the output voltage of the microcomputer U1 does not affect the charging of the capacitor C3 at all, and during discharge, a low signal is output from the output terminal DCHG ST of the microcomputer U1. Since D3) is discharged in the forward direction, the RC coefficient can have sufficient precision when used as a relative comparison value.

The discharged voltage is input through the input terminal VTG IN of the microcomputer U1 and transferred to the '+' input terminal of the comparator inside the microcomputer, which is not shown. In this case, the '-' input of the comparator in the microcomputer U2 is input. As the terminal (that is, VTG REF terminal) is inputted with 2.5V obtained by dividing 5V generated at the output of the constant voltage regulator U2 by the resistors R20 and R23, the microcomputer U1 is built in from the start of discharge. By counting until the result of the comparator is low, you can read the voltage value.

As a result of detecting the voltage of the battery as described above, if the microcomputer U1 outputs a high signal through the output terminal CHG ON, the transistors Q2 and Q1 of the charging control unit 2 sequentially. The charge may be conducted to start charging through the output voltage of the booster 3.

That is, when a high signal is output from the output terminal CHG ON of the microcomputer U1, the voltage supplied from the charger passes through the transistor Q1 of the charge control unit 2 and the constant voltage integrated circuit U3 of the boost unit 3. Since the switching voltage is determined by the capacitor C8, the maximum supply current is determined by the resistor R18, and is supplied by the divided voltage ratio of the resistors R5 and R26. The desired output voltage of the constant voltage is determined.

At this time, the constant voltage collecting circuit U3 switches ON / OFF the input terminal SW_DRV to maintain the selected constant voltage, thereby accumulating and discharging charges in the coil L1, thereby achieving a desired boost. .

In this design, a maximum of 300mA of current is allowed to flow at a constant voltage of 10V.

Of course, while charging is continued in the battery pack BATT as described above, the microcomputer U1 in the controller 1 senses the voltage of the battery and terminates the charging when it is determined that the battery has reached full charge.

As a method of detecting that the battery pack is fully charged as described above, in the case of the nickel-hydrogen battery cell, the voltage of the battery cell is continuously increased during the rapid charging, but when the full charge is reached, the voltage drop of about 25.4 mV per cell is reversed. It was used to generate this.

That is, the microcomputer U1 continuously monitors the voltage of the battery and recognizes the full charge when a voltage lower than the maximum voltage is generated (-dV generation). When the full charge is detected, the microcomputer U1 outputs the output terminal ( CHG ON) outputs a low signal so that the transistors Q2 and Q1 of the charging control unit 2 are sequentially turned off to block the voltage of the charger from being supplied into the battery pack BATT across the boosting unit 3.

In addition, a high signal is output from the output terminal DCHG ON of the microcomputer U1 in the control unit 1 so that the transistor Q5 and the field effect transistor Q4 in the discharge control unit 6 are sequentially turned on. The charging voltage of the BATT is all transmitted to the pin (CHAGE terminal) of the connector 8 so that the charger can recognize that the charging voltage is higher than the full charge voltage.

On the other hand, in the circuit of the present invention there is a temperature sensing unit (4) to prevent overcharging, which uses the principle that the temperature rises during overcharging in the case of nickel-hydrogen battery, typically 0-45 degrees Celsius in the case of nickel-hydrogen battery The battery's protection is included because it needs to be charged inside.

That is, the temperature sensing unit 4 divides the output voltage 5V of the constant voltage regulator U2 into the resistor R6 and the thermistor RT1 and outputs the result of the input terminal THR IN of the microcomputer U1 in the controller 1. Since the microcomputer (U1) is transmitted to the '+' input terminal of another comparator (not shown) existing therein and the '-' input terminal is output from the constant voltage unit 7 as described above. A reference voltage of 2.5V is supplied through the input terminal VTG REF. In general, the thermistor RT1 has a resistance value of about 10 mA at room temperature, so that the output of the comparator is always in a high state.

However, if the temperature of the battery pack (BATT) rises above 50 degrees Celsius due to overcharging, the resistance value of the thermistor (RT1) falls below 5.6 kV and the voltage input to the '+' input terminal of the comparator is 2.5 V or less. Therefore, since the output of the comparator is low, the microcomputer U1 recognizes the overcharge and terminates the charging as described above, thereby preventing damage to the nickel-hydrogen battery cell due to the overcharge.

In this way, the nickel-hydrogen battery pack can be charged using a nickel-hydrogen battery pack charger (including all household vehicles) so that the nickel-hydrogen battery pack can be used in a portable telephone.

As described above, according to the present invention, a nickel-hydrogen battery can be safely charged using a lithium-ion charger as well as a nickel-hydrogen charger, thereby protecting the battery pack and significantly improving its function. In addition, since the user's battery is a nickel-hydrogen battery and the charger is a lithium-ion charger, the battery can be charged normally. Therefore, it is possible to solve the economical loss and inconvenience that the user needs to have a nickel-hydrogen charger. It is

Claims (1)

When the battery pack BATT is connected to the charger and a predetermined voltage is supplied to the pin IDR of the connector 8, the battery voltage is made to be a constant voltage by using the battery pack BATT to supply the driving power to the microcomputer U1 in the controller 1. A constant voltage unit 7; When a high signal is inputted to the input terminal IDR-IN connected to the output terminal of the constant voltage unit 7 while being driven by the voltage supplied from the constant voltage unit 7, the battery pack BATT is connected to the connection terminal of the charger. It recognizes that the battery is connected and controls charging and discharging according to the battery sensed battery temperature and battery voltage, and outputs a low signal through the output terminal (IDR-OUT) to recognize that the charger is continuously connected to the battery. A control unit 1 configured to allow; A charging control unit (2) for supplying the power supplied through the connector (8) to the charging power according to the charging control signal output from the output terminal (CHG ON) of the microcomputer (U1) in the control unit (1); A booster (3) for boosting the voltage supplied from the charge control unit (2) to the charge voltage required by the nickel-hydrogen battery pack (BATT) to allow a constant current to flow in the nickel-hydrogen pack; A temperature sensing unit 4 which detects a temperature change of the battery as a voltage and determines whether or not the controller 1 is overcharged; In accordance with the discharge control signal output from the control unit 1, the nickel-hydrogen battery using the lithium-ion charger comprising a discharge control unit 6 for discharging by supplying the voltage charged in the nickel-hydrogen battery pack (BATT) to the mobile phone side In the charging circuit, A battery voltage sensing unit 5 composed of several resistors R13-R15, a capacitor C3, and a diode D3 detects a voltage of the nickel-hydrogen battery pack Batt and inputs it to the controller 1. Wow; When the nickel-hydrogen battery pack is fully charged, the predetermined voltage drops to prevent the charger from recognizing the full charge and the microcomputer U1 in the controller 1 tracks the charging voltage during charging to A nickel-hydrogen battery pack protection circuit comprising a diode (D1) for detecting the full charge detection method -dV to fully charge.