KR100456448B1 - Built-in charge circuit to battery pack of portable phone - Google Patents

Abstract

The present invention has a built-in charging circuit in the battery pack so that it can be charged using a general adapter for supplying DC power directly to the battery without having to provide a separate auxiliary charging means for charging the mobile phone battery.

The charging circuit unit outputs a charging control signal to the first switch unit while monitoring the current and voltage values input from the current sensing unit and the voltage divider for the power flowing through the power input terminal to maintain the constant current and the constant voltage. Charge control IC unit for controlling the; A current amount detector for outputting a current amount generated at both ends of the resistor R1 connected between the power input terminal and the battery cell to the charge control IC unit; A first switch unit in which a FET Q1 and a zener diode ZD1 are connected in parallel between the current amount detection unit and the battery cell and switched according to a charge control signal input from the charge control IC unit; A voltage divider which outputs a voltage divided by a series of connected resistors R2 and R3 to the charge control IC; And a diode (D1) through which a discharge current flows without affecting the charging circuit unit during discharge.

Description

Built-in charge circuit to battery pack of portable phone}

The present invention relates to a charging circuit embedded in a mobile phone battery pack, and more particularly, to charging a mobile phone battery, a mobile phone battery using a general adapter for supplying a predetermined DC power without using a separate charging device or a mobile phone. Built-in a charging circuit inside the battery pack to charge the power itself to maintain a constant current and a constant voltage when charging the battery cell, but by connecting to a protection circuit in circuit damage from short and external pressure, etc. The present invention relates to a charging circuit embedded in a battery pack of a mobile phone that enables smooth charging and discharging of a battery cell while preventing overcharge or overdischarge due to the present invention.

In recent years, the popularity of mobile phones, which are carried by many people, is easy to carry and store, and the convenience of being able to use them regardless of time and place is increasing. Various information can be provided in real time, and various functions such as video call with anyone in the world in preparation for IMT-2000 (International Mobile Telecommunications-2000) can be provided. The situation requires a talk time.

In general, such a mobile phone is used by a user, so that the user can supply the power of the mobile phone with its own battery, compared to a landline phone, and when the battery is completely discharged, the battery can be recharged through a separate charging device. Afterwards, it can be mounted on a mobile phone and used again. Such a battery charging device includes a general charging device used to convert AC power provided from a home or an office into a DC power source, and a cigar jack charger and a department store using a car cigar jack. It is installed in a public place where a lot of people pay a predetermined price, there is a charge automatic charging device used.

As described above, in order to charge the mobile phone battery, it is charged using a dedicated charging device. In particular, a user must always carry a dedicated charging device which is inconvenient to carry when traveling or traveling. There is a lot of inconvenience when using the phone call is possible only after a certain time has elapsed until the charge.

In the case of the cigar jack charger, since the power supplied from the battery of the car must be supplied, it is always possible to charge only after boarding the vehicle, and fuel is unnecessary due to the acceleration of idling to prevent the discharge of the vehicle battery even during charging. Exhausted, there is a problem of exhaust pollution, even when the user is charged to the discharged battery of the mobile phone using a charge automatic charging device installed in a public place, such as after the user is moved to the place where the charging device is installed In order to receive a charge, a certain amount of payment is inconvenient in use.

In addition, since the shape of the battery changes according to the designed shape of the mobile phone, when the mobile phone is changed, the charging device must also be replaced, and thus there is a problem in that waste of resources is severe, and the charging device is designed because the charging circuit is designed for the battery. There is a problem in that the formation and control of the charging voltage is different from the battery and thus the compatibility is insufficient.

The reason why the problem occurs in charging the battery of the mobile phone as described above can be charged only through a dedicated charging device, looking at the method of charging the conventional mobile phone battery as follows.

In the first method, only the battery is separately stacked and charged in a charging device, and a charging circuit is built in the charging device so that a predetermined DC power can be supplied to the battery. The second method uses a mobile phone having a battery attached thereto. The charging device is coupled to the charging device, and the charging circuit is built in the charging device and the mobile phone so that a predetermined DC power can be supplied to the battery. The third method includes a cigar jack or a jack formed in the mobile phone where the battery is attached. It is a method to charge using a TC jack, a built-in charging circuit in the mobile phone so that a predetermined DC power can be supplied to the battery.

In the conventional methods of charging a mobile phone battery, although a charging target is a battery, a charging circuit for charging the battery is not built in the battery, and a protection circuit is formed in the battery to form a charging circuit of a charging device or a mobile phone. Through charging, it is possible to prevent malfunction due to overcharge, over-discharge and damage due to short or physical shock, and charging can be performed only through a charging device or a mobile phone. There is a problem in that the manufacturing cost of the mobile phone is increased because the battery can be charged only if the charging circuit is built in the battery.

Particularly, in Europe and abroad, a battery is integrated into the mobile phone by using a charging circuit only in a mobile phone without using a separate charging device, and then charged using a predetermined DC power provided through an adapter. Although it is possible to charge by using a general adapter that provides a predetermined DC power without having a separate dedicated charging device at the time, even in foreign countries, it is not possible to charge the battery separately, and always after connecting to a mobile phone, There is a problem that can not be charged if there is no mobile phone because it can be charged using a charging circuit.

The present invention has been made to solve the above-mentioned conventional problems, a built-in protection circuit and a charging circuit in the mobile phone battery pack to supply DC power without using a charging auxiliary device such as a dedicated charging device or mobile phone at the time of charging By using the adapter to charge the cell phone battery directly, the battery is easy to charge the product efficiency is improved, and when supplying a cell phone to the general consumer, there is no need to embed a separate charging device or a charging circuit in the cell phone The purpose is to reduce manufacturing costs and improve the competitiveness of mobile phones and battery products.

A power input stage for achieving the above object; A protection circuit part comprising a protection control IC part, a resistor (R5) (R6) connected to each terminal of the protection control IC part, and second and third switch parts to prevent overcharge and overdischarge during charging of the battery cell; In the mobile phone battery pack for charging and discharging the battery cell, the charging circuit unit is connected to the circuit between the protection circuit unit and the power input terminal, wherein the charging circuit unit for the current flowing through the power input terminal for detecting the amount of current and voltage divider A charge control IC unit configured to control a corresponding circuit element to maintain a constant current and a constant voltage by outputting a charge control signal to the first switch unit while monitoring current and voltage values input from the unit; A current amount detector for outputting a current amount generated at both ends of the resistor R1 connected between the power input terminal and the battery cell to the charge control IC unit; A first switch unit in which a FET Q1 and a zener diode ZD1 are connected in parallel between the current amount detection unit and the battery cell and switched according to a charge control signal input from the charge control IC unit; A voltage divider which outputs a voltage divided by a series of connected resistors R2 and R3 to the charge control IC; It is intended to implement a charging circuit embedded in a mobile phone battery pack consisting of a diode (D1) for flowing a discharge current without affecting the charging circuit unit during discharge.

1 is a circuit diagram embedded in a mobile phone battery pack applied to the present invention

2 is an internal configuration diagram of a charge control IC unit of a charging circuit according to the present invention;

* Description of Signs of Main Parts of Drawings *

1. Battery Cell 10. Charging Circuit

11. Power input terminal 12. Current amount sensing unit

13. First switch section 14. Voltage divider

20. Charge Control IC 21. Differential Amplifier

22. Inverting / Non-Inverting Amplifiers 23. Transconductance Amplifiers

30. Protection circuit part 31. Protection control IC part

32. Second switch section 33. Third switch section

R1, R2, R3, R4, R5, R6: Resistance

Q1, Q2, Q3: FET

D1, D2, D3: Diode

ZD1: Zener Diode

C1, C2, C3: Capacitor

The present invention provides a protection circuit unit 30 for preventing malfunction, overcharge, and overdischarge due to a short or physical shock in charging a mobile phone battery 1 and a charging circuit unit 10 for supplying constant current and constant voltage power to the battery. The circuit can be directly connected to the cell phone battery, but when charging, the battery 1 can be directly charged using a general adapter (not shown) that supplies DC power.

The protection circuit unit 30 included in the mobile phone battery pack is a circuit embedded to prevent overcharging and overdischarging due to a malfunction due to a short circuit or damage due to a physical shock. The battery cell is protected by the protection circuit unit 30. Looking at the process of charging and discharging in (1) is as follows.

Looking at the charging process, since the power of the constant current and the constant voltage supplied through the charging circuit unit 10 is charged in the battery cell 1 to the resistor R5 connected to the V _DD terminal of the protection control IC unit 31. By supplying power to drive the protection control IC unit 31 by the operation to be performed in the initialized state, the power supplied through the charging circuit unit 10 and the (+) terminal of the battery cell (1) Second and third in which the field effect transistors (Q2, Q3) and the diodes (D3) (D4) are connected in parallel in the flow out through the (-) terminal to the (-) terminal of the power input terminal 11. Passing through the switch unit 32, 33, the protection control IC unit 30 turns off the FET Q2 of the second switch unit 32 through the DO terminal to the second switch unit 32 through the diode D2. ), And through the CO terminal, the FET (Q3) of the third switch unit 33 is turned on to flow into the (-) terminal of the power input terminal 11 to smoothly charge. So this can be achieved.

Looking at the process of discharging, that is, when the battery is coupled to the mobile phone to supply power in the inflow to the negative terminal of the battery cell 1 via the mobile phone through the (+) terminal of the battery cell (1) The protection control IC unit 31 turns off the FET Q3 of the third switch unit 33 through the CO terminal so that it can pass through the third switch unit 33 through the diode D3, and the DO terminal. The FET Q2 of the second switch unit 32 is turned on to flow into the negative terminal of the battery cell 1 so that a smooth discharge can be achieved.

Hereinafter, a charging circuit built in a mobile phone battery pack according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a circuit diagram embedded in a mobile phone battery pack according to the present invention, FIG. 2 is an internal configuration diagram of a charge control IC unit 10 of a charging circuit unit 10 according to the present invention, and FIG. 4 is an internal configuration diagram of the protection control IC unit 31 of the protection circuit unit 30, FIG. 4 is a configuration diagram showing the charging current flow applied to the present invention, and reference numeral 311 denotes a logic block R311. R314 is a divider resistor, COMP1 to COMP4 are comparators, Vref ₁ and Vref ₂ are reference voltages, I _{1 to} I ₄ are input terminals of the logic circuit 311, and DO is a logic circuit 311. Is a discharge control signal, CO is a charge control signal of the logic circuit 311.

1 is a circuit diagram embedded in a mobile phone battery pack according to the present invention.

As shown in the present invention, the charging circuit unit 10 and the protection circuit unit 30 is connected to the circuit, the charging circuit unit 10 is a charging terminal, discharge terminal, ( Charge control IC unit 20 for controlling each circuit element to maintain the power input terminal 11 having the terminal and 5-12V power flowing through the power input terminal 11 as the constant current and the constant voltage power. ) And an adapter (not shown) and a battery cell 1 according to a current amount detector 12 for sensing an amount of current flowing into the power input terminal 11 and a charge control signal input from the charge control IC unit 20. A voltage dividing unit 14 and a charge control IC unit for outputting a divided voltage with respect to a voltage charged in a battery, the first switch unit 13 being controlled to cut off the power charged between them or to maintain a constant current and a constant voltage; 20) of normal operation and voltage Constitute a capacitor (C1) to remove the plug (C2) (C3) and the power supply to the diode (D1) to flow in one direction.

According to the present invention, when power is supplied from a general adapter supplying DC power of 5 to 12V, the charging circuit unit 10 is driven to charge the battery cell 1 with constant current and constant voltage, and the protection circuit unit 30 ) Is driven to ensure smooth charging and discharging while preventing overcharge and overdischarge.

The charging circuit unit 10 is formed between the power input terminal 11 and the protection circuit unit 30 coupled to the adapter, the 5 to 12V of flowing through the charging terminal of the power input terminal 11 in the charging circuit unit 10 In charging the battery cell 1, a charge control IC unit 20 is formed to maintain and supply power with constant current and constant voltage, and each pin of the charge control IC unit 20 is connected to a corresponding circuit element. As a result, the battery cell 1 is charged in a state in which the constant current and the constant voltage are maintained with respect to the power introduced through the power input terminal 11.

The charging control IC unit 20 is an IC circuit that controls the power in a linear manner to maintain and supply 5 to 12 V of power introduced into the power input terminal 11 as a constant current and a constant voltage power supply. Looking at the internal configuration to maintain a differential amplifier (21), an inverting / non-inverting amplifier (Inverting / Non-inverting Amplifier) (22) and a transconductance amplifier (Transconductandce Amplifier) (23) is formed and integrated do.

The input terminals of the differential amplifier 21 and the inverting / non-inverting amplifier 22 are connected to Pin1 and Pin6, and the Pin1 and Pin6 are connected to connection points of both ends of the resistor R1 of the current amount sensing unit 12. If a different amount of current is detected while monitoring and reading the amount of current generated at both ends of the resistor R1, the FET Q1 of the first switch unit 13 is controlled through the output terminal of Pin8 to connect between the adapter and the battery cell 1. It cuts off or controls to pass a certain amount of current to stabilize the output current.

The input terminal of the transconductance amplifier 23 is connected to Pin5, and the pin5 reads the voltage generated from the resistors R2 and R3 connected in series with the voltage divider 14 to read the transconductance amplifier ( 23 is applied to the non-inverting input Vsen terminal (not shown), and when a different voltage is detected while monitoring the voltage at the terminal, the FET Q1 of the first switch unit 13 is connected through the output terminal of Pin8. It controls to stabilize the output voltage.

The current amount detecting unit 12 converts a voltage generated in proportion to the amount of current across the resistor R1 mounted between the power input terminal 11 and the battery cell 1 to Pin1 and Pin6 of the charge control IC unit 20. Output and maintain the constant current while monitoring in the charge control IC unit 20.

When the first switch unit 13 receives the charge control signal of the charge control IC unit 20, the first switch unit 13 connects the adapter connected to the charge terminal of the power input terminal 11 and the battery cell 1 to charge. Or to control the interruption between the adapter and the battery cell 1 and to maintain a constant current and a constant voltage, and the FET Q1 and the Zener diode ZD1 are connected in parallel, and the gate of the FET Q1 is connected. Is connected to Pin8 of the charge control IC unit 20 to receive a charge control signal.

Since the voltage divider 14 has resistors R2 and R3 connected in series, a current due to a voltage difference is generated at a connection point of the resistors R2 and R3 so that the voltage generated in the load is controlled. Output to the IC unit 20, the connection point is connected to the pin 5 of the charge control IC unit 20 to be connected to the internal transconductance amplifier 23.

The capacitor C1 is connected to Pin3 of the charge control IC unit 20 to enable normal driving of the charge control IC unit 20, and the capacitor C2 can remove ripple with respect to the charge voltage. The capacitor C3 improves the input ripple of the power flowing into the charging terminal of the power input terminal 11.

The diode D1 does not affect the charge control IC unit 20 at the time of discharging, thereby preventing self-discharge in the battery and smoothly charging at the time of charging.

Looking at the embodiment of the charging by the charging circuit unit 10 and the protection circuit unit 30 built in the mobile phone battery pack configured according to the present invention as follows.

When the connection terminal of the adapter for supplying DC power of 5-12V to the charging terminal of the power input terminal 11 is connected and the power is applied, the operating power is applied to the charging control IC unit 20, and accordingly the charging control IC unit Operation 20 is initialized, and the driver output terminal of Pin8 is controlled to output a charge-on control signal to the first switch unit 13.

When the first switch unit 13 receives the charge-on control signal from the charge control IC unit 20, the FET Q1 is turned on and the charging current flowing into the charging terminal of the power input terminal 11 is the FET Q1. and the diode via the D1) gives applying a charging current to the positive terminal of the battery cell 1, the protection control IC unit 31 of by the resistor (R5) that is connected to the V _DD terminal control the protection IC Power is supplied to drive the unit 31 so that the operation is performed in an initialized state.

The power introduced into the (+) terminal of the battery cell 1 flows out to the (-) terminal of the power input terminal 11 through the (-) terminal to allow a smooth current to flow, but the battery cell (1) In order to prevent the overcharge and over-discharge of the) and to pass through the second 32 and the third switch unit 33 formed.

That is, when the charging current flows through the negative terminal of the battery cell 1, the protection control IC unit 31 turns off the FET Q2 through the DO terminal and the second switch unit 32 through the diode D2. ), The FET (Q3) is turned on via the CO terminal, and is connected to the power input terminal 11 via the (-) terminal of the power input terminal 11 through the third switch unit 33. As shown in FIG. 4, the charging circuit unit (1) is connected to the battery cell 1 as shown in FIG. 4. Referring to FIG. 4, the DO and CO signals for smooth charging and discharging are controlled. When the charging power is connected to the charging terminal of 10), the second switch part Q2 (32) and the third switch part Q3 (33) are all in the OFF state, and thus the terminal voltage V _VSS of Vss is determined by the charging voltage. is higher than the terminal voltage (V _VM). the potential of the Vss terminal 2 as shown in Figure 3 is ∮ as the ground (GND) potential, Through the piezo-resistor R314 non-inverting input terminal of the comparator COMP312 (-) is input to, is lower than the reference voltage Vref _2, and the output of the comparator COMP213 is high, the input terminal I ₂ of the logic circuit 311 has is high is input On the other hand, the V _VM input through the VM terminal 5 is input to the inverting input terminal of the comparator COMP314, and the output thereof becomes high so that high is input to the input terminal I ₄ of the logic circuit 311. The logic circuit 311 The truth table, which defines the input / output operation relationship by the logic gate structure inside, operates as shown in Tables 1 and 2. Therefore, CO outputs a high control signal to turn on the third switch section Q3 (33), DO becomes LOW to turn off the second switch section Q2 (32) so that the charging current flows as shown in FIG. do.

In this case, in order to smoothly charge the battery cell 1, since supply of a constant power by constant current and constant voltage is essential, the output voltage and current are stabilized by the constant current and constant voltage modes set by the charging circuit unit 10. Take a look.

Referring to the case of the constant voltage mode set by the charging circuit unit 10, when the charging power introduced through the charging terminal of the power input terminal 11 passes through the first switch unit 13, the voltage generated in the load is divided into voltages. It is applied to the resistors R2 and R3 connected in series of the unit 14, and the voltage set by the resistors R2 and R3 is read from Pin 5 of the charge control IC unit 20. The voltage value read from Pin 5 is applied to the non-inverting input Vsen terminal of the internal transconductance amplifier 23, and stabilizes the output voltage while monitoring the voltage at the terminal. The driver output terminal is turned on to output a charge control signal to the first switch unit 13, and the FET Q1 of the first switch unit 13 is in accordance with the charge control signal input from the charge control IC unit 20. Controlled to maintain a constant voltage Check it.

That is, when the voltage flowing through the power input terminal 11 is 5V and the voltage divided by the resistors R2 and R3 connected in series with the voltage divider 14 is applied, the charge control IC unit 20 The constant voltage value read from Pin 5 of) is monitored by the non-inverting input Vsen terminal of the transconductance amplifier 23. If the voltage flowing through the power input terminal 11 is abnormally high, the voltage divider 14 A voltage equal to or greater than the reference voltage is applied to the resistors R2 and R3 of the circuit). Stabilizes.

Referring to the case of the constant current mode set by the charging circuit unit 10, when the charging power flowing through the charging terminal of the power input terminal 11 passes through the resistance R1 of the current amount sensing unit 12, the resistance R1. The amount of current generated at both ends is read from Pin1 and Pin6, and the current value read from Pin1 and Pin6 is monitored by an internal circuit consisting of a combination of an internal differential amplifier 21 and an inverted / non-inverted amplifier 22. While stabilizing the output current, if different current values are detected, the output terminal of Pin8 is controlled to output a charge control signal to the first switch unit 13, and the FET Q1 of the first switch unit 13 is controlled. In order to maintain a constant current according to the charge control signal input from the charge control IC unit 20. As described above, when overcharging occurs in the process of charging the battery cell 1 by the charge circuit unit 10, the protection circuit unit (30) Looking at the process to detect this to prevent overcharge, as follows. As shown in Figure 4 as the charging proceeds, the voltage of the battery cell 1 is increased to the V _DD of the protection control IC unit 31 When the terminal voltage V _VDD rises to reach 4.35 V, the voltage divided by the divided resistors R311 and R312 is input to the non-inverting input terminal (+) of the comparator COMP311, and the inverting input terminal (-) of the comparator COMP311 is provided. a is compared to the applied reference voltage Vref1. At this time, the divided voltage R311, according to the partial pressure ratio and the reference set of values of the voltage Vref1 of R312 output of the comparator COMP311 becomes high, the logic circuit 311, the input terminal I ₁ is the high is input, and the internal logic gate of the logic circuit 311 operates as a truth table as shown in Table 3 (CO output truth table for I ₂ , I ₄ , and I ₁ input) to output a LOW signal through the CO terminal. Done. Accordingly, the third switch Q3 33 is turned off so that no charging current flows any more, thereby preventing overcharging.

As described above, after the cellular phone battery is charged according to the present invention, the battery is coupled to the cellular phone and looks at an embodiment of discharging the battery to operate the cellular phone.

Since the current generated at the positive terminal of the battery cell 10 flows into the mobile phone through the discharge terminal of the power input terminal 11, the current is self-discharged in the battery due to the flow of the current into the charging circuit unit 10. The current is discharged through the discharge terminal by the reverse polarity of the diode D1 formed so as to prevent it and not affect the charging circuit unit 10.

In this way, the current generated in the battery cell 1 is discharged through the discharge terminal due to the OFF of the charge control IC unit 20 and the reverse polarity of the diode D1, and through the mobile phone (-) of the power input terminal 11 (- The second and third switch parts 32 and 33 are prevented from being discharged in the negative terminal of the battery cell 1 through the terminal, and the negative terminal of the power input terminal 11 is provided. When the voltage flowing in through the resistor R6 is sensed, the protection control IC unit 31 turns off the FET Q3 through the CO terminal and passes the third switch unit 33 through the diode D3. In addition, the FET Q2 is turned on through the DO terminal to flow into the negative terminal of the battery cell 1 through the second switch unit 32 to smoothly discharge the charging circuit unit 10 as described above. When the over-discharge is in the process of discharging the battery cell 1 by the protection circuit 30 to detect this process to prevent over-discharge As shown in FIG. 4, when the load is connected to the discharge terminal of the charging circuit unit 10, the discharge of the voltage charged in the battery cell 1 starts to flow to the load, and the discharge continues. Accordingly, when the terminal voltage of V _DD gradually decreases to 2.3 V, the output of the comparator COMP311 goes through the divided resistors R311 and R312 to LOW. When the output of the comparator COMP311 goes LOW, the input terminal I of the logic circuit 311 _The LOW signal is input to ₁ , and the internal logic gate of the logic circuit 311 operates as a truth table as shown in Table 4 (DO output truth table for I ₂ , I ₄ , and I ₁ inputs), so that the LOW signal is applied to the DO terminal. The control signal is output so that the second switch part Q2 is turned off so that no further discharge proceeds. That is, before overdischarge, the discharge current flows in the opposite direction to the charging current shown in Fig. 4 during the normal discharge operation, at which time the third switch Q3 33 is OFF (i.e., the CO control signal is low output). When the second switch unit Q2 32 is turned ON (i.e., the DO control signal is high output) and overdischarged, LOW is input to the input terminal I ₁ of the logic circuit 311 as shown in the truth table of Table 4 above. Then, the DO control signal also drops to LOW so that the second switch part Q2 (32) is turned off so that the discharge current is turned off.

As described above, the present invention does not use an auxiliary charging means such as a dedicated charging device or a mobile phone in charging a mobile phone battery, and uses a charging circuit unit within the battery to directly charge the battery using a general adapter for supplying DC power. 10) and the protection circuit unit 30 are incorporated.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those having ordinary knowledge in the technical field to which the present invention belongs, and the above-described embodiments and accompanying It is not limited to the drawing.

The present invention is configured to be built by connecting the protection circuit and the charging circuit to the cell phone battery pack, and to provide a DC power that can be easily obtained on the market without using a dedicated charging device or a mobile phone when charging the battery. The battery can be directly charged through a general adapter, which improves user convenience and product efficiency, and reduces manufacturing costs when manufacturing and selling a mobile phone, thereby improving product competitiveness.

Claims (2)

A power input terminal; A protection circuit part comprising a protection control IC part, a resistor (R5) (R6) connected to each terminal of the protection control IC part, and second and third switch parts to prevent overcharge and overdischarge during charging of the battery cell; In the mobile phone battery pack to charge and discharge the battery cells, A charging circuit unit is connected to the protection circuit unit and the power input terminal in a circuit. The charging circuit unit controls charging while monitoring current and voltage values input from a current amount sensing unit and a voltage divider unit with respect to power flowing through the power input unit. A charge control IC unit which outputs a signal to the first switch unit and controls a corresponding circuit element to maintain a constant current and a constant voltage; A current amount detector for outputting a current amount generated at both ends of the resistor R1 connected between the power input terminal and the battery cell to the charge control IC unit; A first switch unit in which a FET Q1 and a zener diode ZD1 are connected in parallel between the current amount detection unit and the battery cell and switched according to a charge control signal input from the charge control IC unit; A voltage divider which outputs a voltage divided by a series of connected resistors R2 and R3 to the charge control IC; A charging circuit embedded in a mobile phone battery pack, characterized in that consisting of; diode (D1) for flowing a discharge current without affecting the charging circuit portion during discharge. The method of claim 1, The charge control IC unit is connected to a connection point of both ends of the resistor R1 of the current amount sensing unit, and reads and monitors the current value generated at both ends of the resistor R1 to charge the FET Q1 to the FET Q1 through the output terminal. A differential amplifier and an inverting / non-inverting amplifier for outputting a stabilizing output current; Transconductance amplifier which stabilizes output voltage by outputting charge control signal to FET Q1 of switch part through output terminal while monitoring by reading voltage value generated from resistors R2 and R3 connected in series of voltage divider Charging circuit built in the mobile phone battery pack, characterized in that consisting of.