KR100619890B1 - A method and a apparatus of charging constant current at rechargeable battery for mobile phone - Google Patents

Abstract

The present invention is to output a portable terminal battery with a constant current charging current precisely and precisely using a bias diode to suit the characteristics of the ABB, input a digital control signal for controlling the charging current and control by the internal current An ABS unit for outputting a signal; An FBT controlling the voltage applied to the gate by the control signal of the ABS unit and controlling the magnitude of the charging current; A bias diode connected to the FFT gate and outputting a forward internal voltage as a bias voltage; A bias resistor connected to the source terminal of the bias diode and FT to determine the bias voltage; A first step of connecting to a drain terminal of the FFT and including a battery unit configured to charge by a charging current, and further determining whether to charge the mobile terminal battery with a constant current; A second process of connecting a diode in series with the bias resistor of the FTC when the constant current is charged; And a third process of outputting a constant current for charging controlled by the bias voltage adjustment of the FM. There is an effect of outputting a precisely controlled charging current with a twice wider control range.

Description

A constant current charging device and method for a mobile terminal battery {A METHOD AND A APPARATUS OF CHARGING CONSTANT CURRENT AT RECHARGEABLE BATTERY FOR MOBILE PHONE}

1 is a functional configuration of a constant current charging device of a battery of a portable terminal of the prior art,

Figure 2 is a state diagram of the bias voltage change compared to the digital control signal of the battery constant current charging device of the prior art,

3 is a state diagram of charge current change with respect to a bias voltage of a battery constant current charger of the prior art;

4 is a functional configuration of the constant current charging device of the battery of the present invention terminal;

5 is a flow chart of a constant current charging method of a mobile terminal battery according to the present invention;

6 is a state diagram of charge current change compared to a digital control signal of a battery constant current charger according to an embodiment of the present invention;

7 is a diagram showing a charging current state controlled by a digital control signal according to an experimental example of the present invention and the prior art.

** Explanation of symbols on the main parts of the drawing **

100: ABS 110: Bias Diode 120: Bias Resistor

130: FT 140: Forward diode 150: Charge part

160: load resistance 170: battery unit

The present invention provides a constant current charging of a mobile terminal battery in a precisely controlled state. In particular, a bias diode is used by using ADI's TYPHOON chip, which controls charging current according to the earth function curve characteristics. The present invention relates to a constant current charging device and method for a portable terminal battery that outputs a constant current charging current that is precisely controlled using a connected P-type FET.

The mobile terminal (UE: USER EQUIPMENT) freely moves in the service area (SERVICE AREA) formed by the corresponding base station (RAN: RADIO ACCESS NETWORK) of the registered mobile communication system and monitors and monitors the mobile switching center (MSC). It is a high-tech wireless communication device that allows an individual to carry it anywhere while always carrying it directly by wirelessly connecting and communicating with a desired party anytime and anywhere through a communication path established by control and switching.

The mobile terminal (UE) is guaranteed mobility to communicate by the operating power supplied normally in the mobile state, the mobile battery can not be used as general operating power as the operating power, removable and easy to replace (BATTERY) The power supplied from) is used as the operating power.

The battery is simply supplied with a discharged power by the discharge (DISCHARGE), and the end of life by charging and discharging once is called a "DUMB" battery, the charging (CHARGING) and the discharging (DISCHARGING) Repeated reuse of the process is called a RECHARGEABLE battery.

In general, the battery has a maximum voltage of about 4.2 volts (V) normally output in a fully charged state, outputs a current by discharging, and decreases an output voltage as discharge progresses, and rapidly reaches about 3.2 volts (V). Discharge is possible, and the internal electronic circuit and the operation program of the portable terminal do not operate normally when about 3.2 volts or less are supplied. Therefore, below about 3.2 volts (V) to recover and protect the normal characteristics of the battery. Shut off further rapid discharge.

The 3.2 volt (V) is referred to as a cut-off voltage, the current output from the battery is cut off to protect the charging and discharging chemical characteristics of the battery and to prevent the malfunction of the portable terminal, and the time is counted by the control of the portable terminal. The minimum current is output only to essential functional units such as the functional unit.

The battery discharged in the cutoff state as described above should be charged (CHARGE), the charging method, there is a constant current (CC: CONSTANT CURRENT) charging method and a constant voltage (CV: CONVANT VOLTAGE) charging method, the present invention Relates to a constant current (CC) charging method.

The portable terminal is manufactured in a compact and lightweight to ensure mobility, in particular, the charging and discharging battery has a problem that the smaller the size and weight while adopting a structure that increases the capacity sensitively reacts to heat and shock and becomes unstable easily. There is.

In addition, the battery may easily generate heat when more than the allowed charging current is temporarily applied.

Therefore, there is a need to develop a constant current charging device that outputs a precisely controlled charging current to a charge / discharge battery for a portable terminal.

Hereinafter, according to the prior art, a constant current charging device for a portable terminal battery will be described with reference to the accompanying drawings.

1 is a diagram illustrating a function of a constant current charger of a portable terminal battery according to the prior art, and FIG. 2 is a state diagram of a bias voltage change compared to a digital control signal of a battery constant current charger according to the prior art. 3 is a state diagram of a charge current change relative to a bias voltage of a battery constant current charger according to the related art.

Referring to FIG. 1, a constant current charging device for a portable terminal battery according to the prior art will be described. ABB 10, which is a TYPHOON chip of ADI, inputs a 10-bit digital control signal as a charge control signal. The analog control unit 12 converts and outputs an analog signal from the analog unit (DAC: DIGITAL TO ANALOG CONVERTER) 12, and the analog control signal converted and output from the analog unit 12 is input to the comparator 14 to stabilize the level, and the FET It is applied to the gate (G) terminal of (16).

The FET 16 changes the amount of internal current I passed by the charging current control signal applied to the gate terminal, and the internal current I is varied in the range of 0 to 5 milliamps (mA). The internal current I flows to ground through a resistor 18.

That is, the amount or magnitude of the internal current I passed through the FET 16 is changed by the 10-bit digital control signal applied to the analog unit DAC.

The internal current I flowing through the ABB 10 is supplied from the charging unit 50, and is supplied through the bias resistor 20 through the forward diode 40 to block the current flowing in the reverse direction.

The voltage across the bias resistor 20 is a value obtained by multiplying the internal current (I) value supplied from the charging unit 50 by the bias resistor 20 value by the Ohm's law. Vgs), and is applied as a bias voltage Vgs between the gate and source terminals of the FET 30.

As the FET 30 is P type, the higher the + voltage applied to the gate, the greater the amount of current passing through, and the current becomes the charging current Ichg.

That is, in the constant current (CC) charging control controlled by the program of the ABB 10, the FET 16 is the internal current (I) by the 10-bit digital value control applied to the analog unit 12 The internal current I is converted into a voltage by Ohm's law with the resistor 20, and the voltage becomes a bias voltage Vgs, so that the gate terminal of the P-type FET 30 is controlled. It is applied to control the magnitude of the charging current (Ichg).

In other words, the bias voltage Vgs applied to the gate terminal of the P-type FET 30 is controlled by the 10-bit digital control signal of the ABB 10, and the magnitude of the charging current Ichg is controlled.

Since the charging current Ichg controlled by the P-type FET 30 is applied to the battery unit 70 through the resistor 60, the battery unit 70 is charged.

Referring to FIG. 2, it is a graph showing a state of change of the bias voltage Vgs by the digital control signal DAC, which is caused by the battery constant current charging device according to the prior art. : ESTIMATION The bias voltage values (Vgs) and measured bias voltage values (Vgs) are shown in tables and charts, respectively.

Referring to the diagram of FIG. 2, as an example, a decimal 705 value of a 10-bit digital control signal (DAC) is applied to the analog unit 120 of the ABB 10 to thereby gate the P-type FET 30. As the bias voltage applied to the terminal, it can be seen that the calculated and estimated bias voltage (Vgs) value is about 1.15 millivolts (mV), and the measured bias voltage (Vgs) value is about 1.14 millivolts (mV).

Referring to FIG. 3, the state of charge current change with respect to the bias voltage of the battery constant current charger according to the related art is illustrated. For example, the bias voltage Vgs applied to the gate terminal of the P-type FET 30 is described. Is applied at 1.14 millivolts (mV), it is confirmed that the charging current Ichg is supplied to the battery unit 70 at 187 milliamps (mA).

As described above, the relationship between the digital control signal DAC, the bias voltage Vgs, and the charging current Ichg is listed and recorded in the table of FIG. 2, and the Vsense value of the table is a value measured by the resistor 60. .

However, referring to FIG. 3, it is confirmed that the charging current Ichg value which is changed with respect to the bias voltage Vgs forms an exponential function curve.

That is, since the battery charger according to the related art changes rapidly or sensitively such as an exponential function curve by an input digital control signal DAC, there is a problem in that the charging current cannot be precisely controlled in the constant current charging method.

The present invention reduces the bias resistance by adding a bias diode between the gate and the source of the FM to control the magnitude of the charging current of the battery charging device of the portable terminal, so that the portable terminal precisely controls the charging current with the divided bias voltage It is an object to provide a constant current charging device and method for a battery.

The present invention devised in order to achieve the above object, the ABS unit for inputting a digital control signal for controlling the charging current and outputting a control signal by the internal current; An F to control the voltage applied to the gate by the control signal of the ABS and to control the magnitude of the charging current; A bias diode connected to the gate of the FM to output a forward internal voltage as a bias voltage; A bias resistor connected to the bias diode and the source terminal of FFT to determine a bias voltage; A battery unit is connected to the drain terminal of the FM and includes a battery unit for charging with a charging current.

In addition, the present invention has been made in order to achieve the above object, the first process of determining whether or not to charge the mobile terminal battery constant current; A second step of connecting a diode in series with the bias resistor of the FTC when the constant current is charged; And a third process of outputting the charging constant current controlled by the bias voltage adjustment of the FM.

Hereinafter, the present invention will be described with reference to the accompanying drawings, a constant current charging device and method of a portable terminal battery.

4 is a functional configuration diagram of a constant current charging device of a portable terminal battery according to the present invention, FIG. 5 is a flowchart of a constant current charging method of a portable terminal battery according to the present invention, and FIG. Figure 7 is a state diagram showing the charge current change compared to the digital control signal of the battery constant current charging device according to the experimental example, Figure 7 is a state diagram showing the charge current controlled by the digital control signal according to the experimental example of the present invention and the prior art.

According to the present invention with reference to FIG. 4, the constant current charging device of the portable terminal battery is described by inputting a digital control signal (DAC) for controlling the charging current and outputting a control signal by the internal current (I). And an ANALOG BASEBAND PROCESSOR (ABB) unit 100 formed of TYPHOON chips (CHIP),

A bias diode 110 connected to the gate of the FM 130 and outputting a forward internal voltage as a bias voltage;

A bias resistor 120 connected to the source terminal of the bias diode 110 and the F 130 to determine a bias voltage;

The voltage applied to the gate (GATE) is controlled by the control signal of the ABS unit 100 to control the magnitude of the charging current, and outputs the forward internal voltage of the bias diode 110 and the bias resistor 120. And a voltage obtained by processing the internal current I of the ABS unit 100 with an Ohm law, and is supplied as a bias voltage Vgs between a source terminal and a gate terminal, and the bias voltage Vgs. Since the charging current Ichg is controlled and outputted at a predetermined rate with respect to the change of the power supply, the size of the charging current Ichg applied from the charging unit 150 is controlled by the internal current I signal of the ABS unit 100. FET 130 for outputting,

A forward diode 140 connected to the source terminal of the FM 130 to allow a current to flow in a forward direction;

A charging unit (TA: TRAVEL ADAPTER) 150 connected to the forward diode 140 to supply a charging current Ichg of the battery unit 170;

A load resistor 160 connected between the drain terminal of the FM 130 and the battery unit 170 to apply a charging current Ichg to the battery unit 170;

The battery unit 170 connected to the drain DRAIN terminal of the FM 130 and charged by the charging current Ichg is included.

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

The ABS unit 100 is a TYPHOON chip provided by ADI (ANALOG DEVICE INC), and inputs a 10-bit digital control signal (DAC) and converts it into an analog signal. Since the (FET) is controlled, the internal current I flows in a controlled state by the built-in FET.

The internal current I is supplied from the charging unit TA through the forward diode 140 and passes through the bias resistor 120 and the bias diode 110. Supplied to.

The bias resistor 120 and the bias diode 110 determine the bias voltage Vgs of the FT 130, and since the bias diode 110 is connected in the forward direction, it is always constant 0.6 volts (V). Is applied to the bias voltage (Vgs) of the FBT 130, and the voltage obtained by processing the internal current (I) flowing through the bias resistor 120 according to the Ohm's law is The bias voltage Vgs of the FT 130 is applied.

Generally, about 1.2 volts is required as the bias voltage Vgs of the FT 130, and about 0.6 volts is applied by the bias diode 110, so that the bias resistor 120 receives the remaining about 0.6 volts. Supply it.

Therefore, if the internal current I value is constant, the bias resistor 120 value is reduced, and the bias voltage is controlled in a subdivided state as follows.

(Mathematical formula)

Delta Vgs = ((max I) / (max value of digital control signal)) * bias resistance

The delta Vgs is the precision, the maximum I is the internal current value that can flow to the maximum, the maximum value of the digital control signal is a value by the DAC signal consisting of 10 bits (BIT), 1024 in decimal, the bias resistor The value is a resistance value of the bias resistor 120.

The smaller the value of the bias resistor 120 in the above formula is, the smaller the delta Vgs value is, which indicates that the precision or RESOLUTION is increased.

That is, since the bias voltage Vgs is not sensitive to a change in the value of the digital control signal DAC, a large range of digital control signal DAC values must be assigned.

Referring to the accompanying Figure 6, according to the experimental example of the present invention, the state diagram of the charge current change compared to the digital control signal of the battery constant current charging device.

The thick line of FIG. 6 is an exponential curve obtained by calculating input digital control signal (DAC) values from 590 to 750, and the dotted line indicates the charging current Ichg value measured by the experiment.

Since the charging current Ichg controlled as described above is applied to the battery unit 170 via the load resistor 160, the battery unit 170 is charged.

Referring to FIG. 7, the present invention and the prior art are examples of the state of charge, which is controlled by the digital control signal DAC.

In FIG. 7, the dotted line is a state of the art and a state using a resistor for setting the bias voltage, and the dotted line of the circle is according to the present invention and the bias voltage is set using a resistor and a diode. Is also.

As shown in FIG. 7, the conventional technique using only resistance shows that the relative digital control signal (DAC) value is 1 to 5, and the present invention displays a value of 1 to 10, so that the control can be precisely doubled. .

That is, since the same charging current is controlled to be output by using twice as many digital control signal values, the accuracy is increased.

Hereinafter, with reference to the accompanying Figure 5, by the present invention, a constant current charging method of a mobile terminal battery will be described.

A first step (S100) of determining whether to charge a battery for charging / discharging a battery of a mobile communication terminal (CONTERANT CURRENT);

In the case of charging the constant current (CC) in the first process (S100), a bias bias (BIAS) diode (DIODE) having the same forward direction by the source terminal and the gate terminal is applied to the bias (BIAS) resistance of the FET. A second process (S110) for connecting in series (SERIAL),

The bias voltage (Vgs) of the FT (FET) by the second process (S110) is precisely and precisely controlled by adjusting the internal current (I) value flowing through the bias resistor, and finely controlled by the control of the bias voltage. Since the controlled charging constant current Ichg is output to the battery BATTERY, a third process S120 of charging is performed.

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

It is determined whether the mobile terminal battery is charged with a constant current (CC: CONSTANT CURRENT) (CHARGE), and when it is desired to charge with a constant current (CC) in the determination (S100), the bias resistance of the P-type FET 130 The bias diode 110 is connected to the 120 in series (SERIAL) (S110).

In step S110, a digital control signal DAC is input to the ABS unit 100 to control the bias voltage of the P-type FET 130 in which the bias diode 110 is connected in series.

Since the internal current I is set by the digital control signal DAC, and the internal current I flows through the bias resistor 120, a voltage drop by the bias resistor 120 occurs, and the bias In addition to the forward internal voltage by the diode 110 is applied to the bias voltage (Vgs) of the FM 130.

The FT 130 applied with the controlled bias voltage Vgs outputs the corresponding charging current as the constant current CC, thereby charging the battery unit 170 (S120).

Therefore, the present invention controls the bias voltage (Vgs) of the FM 130 by a bias resistor having a smaller resistance value, so that the charging current is precisely and precisely controlled by a wide range of digital control signal (DAC) values. There is an advantage.

According to the present invention, the forward diode and the resistor are used to set the bias voltage of the P-type FET, thereby reducing the value of the resistor in half and doubling the control range.

In addition, since the charging current is output by controlling the bias voltage of the P-type FET in a twice wide control range, there is a convenient effect in improving the stability of the charging device and improving the reliability.

Claims (7)

An ABS unit for inputting a digital control signal for controlling charging current and outputting a control signal based on an internal current; An F to control the voltage applied to the gate by the control signal of the ABS unit and to control and output the magnitude of the charging current; A bias diode connected to the FFT gate and outputting a forward internal voltage as a bias voltage; A bias resistor connected to the bias diode and the source terminal of FFT to determine a bias voltage; A constant current charging device for a portable terminal battery, characterized by comprising a battery portion connected to the drain terminal of the FM and charged by a charging current. According to claim 1, A load resistor connected between the drain terminal of the FM and the battery unit to apply a charging current to the battery unit; A forward diode connected to the source terminal of the FM to allow current to flow in a forward direction; And a charging unit for supplying the charging current of the battery unit by connecting to the forward diode. The method of claim 1, wherein the FFT, A forward internal voltage of the bias diode and a voltage obtained by performing ohmic law processing of the internal current of the bias resistor and the ABS unit are supplied as a bias voltage between the source terminal and the gate terminal, and the charging current is changed at a predetermined ratio to the change of the bias voltage. A constant current charging device for a portable terminal battery, characterized in that the control is configured to control the size. The method of claim 3, wherein the FFT, The constant current charging device of a portable terminal battery, characterized in that for controlling the magnitude of the charging current applied from the charging unit by the internal current signal of the ABS unit. Determining whether to charge the mobile terminal battery with a constant current; A second process of connecting a diode in series to the bias resistor of the FTC when the constant current is charged; And a third process of outputting the charging constant current controlled by the bias voltage adjustment of the FM. The method of claim 5, wherein the second process, And a diode connected in the same forward direction by the source terminal and the gate terminal of the FM terminal in series with a bias resistor. The method of claim 5, wherein the third process, And a bias voltage of the FT is controlled by a change in an internal current value flowing through the FFT bias resistor.

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