TWI434488B - Multi-purpose power management apparatus, power path control circuit and control method therefor - Google Patents

Description

Multipurpose power management device, charging path control circuit and control method thereof

The invention relates to a multi-purpose power management device, a power supply path control circuit and a control method thereof, which can automatically determine whether a charging management circuit needs to be activated according to a connection mode between a system load and a battery, and thus can be flexibly applied to a system load directly or indirectly. Connect different battery drains of the battery.

Figure 1 shows a schematic diagram of a prior art power supply system. Referring to FIG. 1, a switching power supply 1a is used in the power supply system 10, and external power is converted from the input terminal Vin to the output terminal Vout, and the output terminal Vout is supplied to the system load (for example, a computer host). Charge the battery Batt. When there is no external power supply at the input, the battery Batt will output power to the output Vout. The feedback circuit 13 includes two series resistors R1 and R2, wherein one end of R1 is coupled to the output voltage Vout, one end of R2 is coupled to the ground potential, and the feedback signal FB1 is taken from the voltage division on the resistor R2. The error amplifier 11 receives the feedback signal FB1 and compares the reference voltage Vref1 to generate the error signal Comp1 to the pulse width modulation (PWM) signal generator 12. The PWM signal generator 12 generates a switching signal according to the error signal Comp1 to respectively switch the upper bridge transistor Q1 and the lower bridge transistor Q2, convert the input voltage of the power input terminal Vin into a current through the inductor L, and supply current from the power output terminal Vout. To charge the battery Batt. The upper bridge transistor Q1 and the lower bridge transistor Q2 form a switching circuit 14. In order to control the charging current of the battery Bat, a sensing resistor RS is disposed between the output terminal Vout and the battery Bat, and the voltage across the sensing resistor RS is detected by the error amplifier 16 and input to the PWM signal generator 12, thereby controlling The charging current to the battery Bat is within the specified range. Such prior art generally integrates the error amplifier 11, the PWM signal generator 12, the switching circuit 14 and the error amplifier 16 into a chip or a device. However, such a chip or device is only suitable for the battery Batt transmission resistance RS in FIG. The configuration directly connected to the output Vout cannot be used in the power supply system in Figure 2 below.

Referring to Fig. 2, the power supply system 20 includes a switching power supply 1a, a charge management circuit 2a, a battery Batt, and a PMOS transistor 27. The switching power supply 1a converts external electric energy from the input terminal Vin to the output terminal Vout, and the output terminal Vout supplies the system load (for example, the computer main body) and charges the battery Batt. When there is no external power supply at the input, the battery Batt will output power to the output Vout. The power supply system 20 detects whether the battery Batt needs to be charged or stops charging to control the PMOS transistor 27 to turn on or off the charging current flowing to the battery Batt.

The feedback circuit 26 includes two series resistors R3 and R4, wherein one end of R3 is coupled to the battery Batt output voltage Vbatt, one end of R4 is coupled to the ground potential, and the feedback signal FB2 is taken from the voltage division on the resistor R4. The error amplifier 21 receives the feedback signal FB2 and compares the reference voltage Vref2 to generate the error signal Comp2. The error amplifier 24 detects the voltage across the sense resistor RS and outputs an error signal Comp4, and the error amplifier 23 compares the error signal Comp4 with the reference voltage Vref3 and outputs an error signal Comp3. The adder 25 adds the two error signals Comp2 and Comp3, and outputs the summed signal to the charge controller 22. The charge controller 22 determines to turn the PMOS transistor 27 on or off based on the summed signal to determine whether the battery Batt needs to be charged or saturated without recharging.

Such prior art generally integrates the error amplifier 11, the PWM signal generator 12, the switch circuit 14, the error amplifiers (21, 23, 24), the charge controller 22, and the adder 25 into a chip or a power management device 2d. However, the power management device is only suitable for the configuration in which the battery Batt transmission resistor RS and the PMOS transistor 27 are connected to the output terminal Vout in FIG. 2, and cannot be used for the power supply of the PMOSless transistor 27 in the above FIG. system.

In view of the above, the present invention is directed to the above-mentioned deficiencies of the prior art, and provides a multi-purpose power management device, a power supply path control circuit, and a control method thereof, which can automatically determine whether the charging management circuit needs to be activated according to the connection mode between the system load and the battery. Therefore, it can be flexibly applied to different power consuming devices in which the system load is directly or indirectly connected to the battery by a switch.

One of the objects of the present invention is to provide a multi-purpose power management apparatus.

Another object of the present invention is to provide a charging path control circuit.

It is still another object of the present invention to provide a charging path control method.

In order to achieve the above object, in one aspect, the present invention provides a multi-purpose power management apparatus for controlling power conversion from input power to output power and charging of a battery from output power, the multi-purpose power management The device comprises: a switching circuit comprising at least one first power transistor; a switch control circuit for generating a switching signal for controlling the power transistor to control power conversion from the input power to the output power; and a charging management circuit for Controlling the output power to charge the battery; and a path selection circuit for determining whether to use the charge management circuit to control charging of the battery.

In the multi-purpose power management device, when the output power and the battery are connected by a second power transistor, the path selection circuit selects the charge management circuit to operate the second power transistor to control charging of the battery; When the output power and the battery are not connected by a second power transistor, the path selection circuit does not select the charge management circuit to control the charging of the battery.

In one embodiment, the path selection circuit includes a multiplexer that determines whether to use the charge management circuit to control charging of the battery based on an external setting signal.

In another implementation, the charging management circuit generates an output signal, which is output from a pin, and wherein the path selection circuit includes: a detection signal generator, the detection signal generator generates a detection signal from The pin is output to generate a detection voltage; a comparator compares the detection voltage with a reference voltage; and a multiplexer determines whether to use the charge management circuit to control charging of the battery according to the output of the comparator In one embodiment, the charge management circuit includes a first error amplifier, the first error amplifier generates a first error signal according to information about a battery charging current, and the path selection circuit determines the first error signal. Transfer to the switch control circuit or the charge management circuit.

In another aspect, the present invention provides a charging path control circuit for selecting at least one control loop based on an output power and a connection relationship between batteries, the charging path control circuit comprising: a charging management circuit for controlling the output The charging of the battery by the power; and a path selection circuit determining whether to use the charging management circuit to control charging of the battery according to the output power and whether a power transistor is disposed between the batteries.

In another aspect, the present invention provides a charging path control method including: converting an input power into an output power; charging a battery from the output power via a charging path; detecting whether a charging path is provided a power transistor; a power transistor is disposed on the charging path, the power transistor is controlled to control charging of the battery; and when a power transistor is not disposed on the charging path, the input power and the output power are controlled Conversion to control charging of the battery.

Preferably, the charging path control method further comprises: detecting a current on the charging path to generate information about a charging current of the battery; and when a power transistor is disposed on the charging path, using the information feedback control to control the power a crystal; and when a power transistor is not disposed on the charging path, the information is used to control the conversion of the input power and the output power.

In the above charging path control method, the step of detecting whether a power transistor is disposed on the charging path preferably includes: providing a pin, the pin is connected to the gate of the power transistor, or grounded; generating a detect The test signal is output from the pin to generate a detection voltage; and the detection voltage is compared with a reference voltage to determine whether the power transistor is provided.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

The drawings in the present invention are schematic and are mainly intended to indicate the relationship between the functions of the various elements and the signals between the elements, and the dimensions, distances, etc. are not drawn to scale.

Please refer to FIG. 3 and FIG. 4 , which shows that the multi-purpose power management device 3 d of the present invention can be used with different circuit board configurations, and can also be applied to the battery Batt through the resistor RS directly connected to the output terminal Vout in FIG. 1 . The arrangement method can also be applied to the arrangement in which the battery Batt transmission resistor RS and the PMOS transistor 27 are connected to the output terminal Vout in FIG. 2, which are illustrated in FIGS. 3 and 4, respectively. How the multi-purpose power management device 3d recognizes which configuration is connected, and can be manually set by an external signal. In one embodiment, it can be connected to the transistor 27 according to the multi-purpose power management device 3d (or not connected to the battery). The pin potential of the crystal 27 is connected to be automatically judged.

Referring to FIG. 3, the power supply system 30 includes a switching power supply 3a, a charge management circuit 3b, a battery Batt, and a transistor 27 (the transistor 27 is a PMOS transistor, but may of course be an NMOS transistor). And a path selection circuit 3c. The switching power supply 3a controls the power conversion between the input terminal Vin and the output terminal Vout, the charging management circuit 3b controls the charging of the battery Batt, and the path selecting circuit 3c according to whether or not the transistor is provided between the output terminal Vout and the battery Batt. 27, and selecting to return the charging current information of the battery Batt to the switching power supply 3a or the charging management circuit 3b.

In detail, the switching power supply 3a converts external power from the input terminal Vin to the output terminal Vout, and the output terminal Vout supplies the system load and charges the battery Batt. When there is no external power supply at the input, the battery Batt will output power to the output Vout. The power supply system 30 detects whether the battery Batt needs to be charged or stops charging to control the PMOS transistor 27 to turn on or off the charging current flowing to the battery Batt.

The feedback circuit 13 includes two series resistors R1 and R2, wherein one end of R1 is coupled to the output voltage Vout, one end of R2 is coupled to the ground potential, and the feedback signal FB1 is taken from the voltage division on the resistor R2. In the switching power supply 3a, the error amplifier 11 receives the feedback signal FB1 and compares the reference voltage Vref1 to generate an error signal COmp1 to the PWM controller 12. The PWM signal generator 12 generates a switching signal according to the error signal Comp1 to respectively switch the upper bridge transistor Q1 and the lower bridge transistor Q2, and convert the input voltage of the power input terminal Vin into a current through the inductor L, and supply and output from the power output terminal Vout. The current charges the battery Batt. The upper bridge transistor Q1 and the lower bridge transistor Q2 form a switching circuit 14. In Fig. 3, since the PMOS transistor 27 is provided between the output terminal Vout and the battery Batt, the multiplexer 32 in the path selection circuit 3c selects the path to the adder 25 and does not select the output to the adder. The path of 34 (details of the path selection circuit 3c are explained later); therefore, in the switched power supply 3a, the adder 34 accepts only the error signal Comp1. Further, the error amplifier 11, the adder 34, and the PWM signal generator 12 constitute a switch control circuit 15.

The feedback circuit 26 includes two series resistors R3 and R4, wherein one end of R3 is coupled to the battery Batt output voltage Vbatt, one end of R4 is coupled to the ground potential, and the feedback signal FB2 is taken from the voltage division on the resistor R4. In the charge management circuit 3b, the error amplifier 21 receives the feedback signal FB2 and compares the reference voltage Vref2 to generate the error signal Comp2. The error amplifier 24 detects the voltage across the sense resistor RS and outputs an error signal Comp4, and the error amplifier 23 compares the error signal Comp4 with the reference voltage Vref3 and outputs an error signal Comp3. Since the multiplexer 32 in the path selection circuit 3c selects the path to the adder 25, the adder 25 adds the two error signals Comp2 and Comp3, and outputs the summed signal to the charge controller 22, which adds the total signal. Battery voltage and information on the battery's Batt charging current. The charging controller 22 determines whether the battery Batt needs to be charged or saturated without recharging according to the sum signal, and outputs a signal PPCTRL (Power Path Control) to turn on or off the PMOS transistor 27.

In this embodiment, the path selection circuit 3c includes a comparator 31, a multiplexer 32, and a detection signal generator 33. The detection signal generator 33 generates a detection signal, and detects the external connection state of the pin P through the output node PPCTRL and the pin P of the charge controller 22. In Fig. 3, since the pin P is connected to the PMOS transistor 27, the detection signal generated by the detection signal generator 33 generates a higher voltage at the node PPCTRL. The negative input terminal of the comparator 31 receives the voltage generated by the detection signal, and compares it with the reference voltage Vref4 of the positive input terminal, and then outputs a control signal to the multiplexer 32 to select the transmission path of the error signal Comp3. The path selection circuit 3c should preferably set the path only when the system is started or reset to prevent the output signal PPCTRL of the charge controller 22 from affecting the path selection circuit 3c when the system enters the normal operating state. In an embodiment, when the power supply system 30 is powered on, a Power-On Reset (POR) signal can be used as an enable signal to control the comparator 31 and/or the detection signal. Whether the generator 33 has an effect. When the boot phase is completed, the comparator 31 and/or the detect signal generator 33 are disabled, causing the multiplexer 32 to determine the selected path without being disturbed by the change in the signal PPCTRL.

Compared with FIG. 3, the system load in the power supply system 40 in FIG. 4 is only connected to the battery Batt by the sensing resistor RS, and the PMOS transistor 27 is not disposed therebetween, so the charging controller 22 outputs the signal PPCTRL. The foot P is grounded. The negative input terminal of the comparator 31 is also connected to the ground terminal, and after comparing with the reference voltage Vref4 of the positive input terminal, the control signal is output to the multiplexer 32 to selectively transmit the error signal Comp3 to the adder 34. The adder 34 adds the totals Comp1 and Comp3 and outputs them to the PWM signal generator 12. In an embodiment, the switch control circuit 15, the switch circuit 14, the error amplifiers (11, 21, 23, 24), the charge controller 22, the adders (25, 34), and the path selection circuit 3c may be integrated into a wafer or In a multi-purpose power management device 3d, such a chip or device can be adapted to the application example in which the battery Batt is connected to the output terminal Vout by the PMOS transistor 27 and the sensing resistor RS in FIG. 3, and can also be adapted to FIG. The application example of the middle battery Batt connected to the output terminal Vout by the sensing resistor RS. However, the circuits and components included in the multi-purpose power management device of the present invention are not limited thereto. For example, when the operating power of the power transistor in the switch circuit 14 is too high, the switch circuit 14 may not be integrated into the multi-purpose power management device 3d. Inside.

The above embodiment exemplifies that the path selection circuit 3c can automatically detect whether the transistor 27 is set in the path for charging the battery Batt to decide to feedback the charging current information of the battery Batt to the switching power supply 3a or the charging management circuit 3b. . Of course, as shown in FIG. 5, the feedback path of the battery Batt charging current information may also be set by a setting signal from the outside of the chip or the device. In this case, only the multiplexer 32 is required in the path selecting circuit 3c. .

6A-6B illustrates two embodiments of the detection signal generator 33. The detection signal generator 33 can be, for example, a weak current source or a resistor, and the upper end is connected to a suitable voltage (such as, but not limited to, a wafer operating voltage). VDD), the lower end is coupled to the output node PPCTRL (pin P) of the charging controller 22, and when the system is activated or reset, if the pin P is coupled to the PMOS transistor 27, the detection signal generator 33 can pull The voltage of the high node PPCTRL, on the other hand, if the pin P is grounded, the voltage of the node PPCTRL cannot be pulled high. When the system is in normal working state, the voltage of the node PPCTRL is controlled by the output of the charging controller 22, and is not affected by the detection signal generator 33.

FIG. 7A-7B illustrates two other embodiments of the detection signal generator 33. In the two embodiments, the detection signal generator 33 further includes a switch SW that is turned on by the power-on reset signal POR. When the system enters the normal working state after the startup phase is completed, the switch SW is turned to an open circuit to reduce power consumption.

Referring to Figures 8 and 9, there is shown an application of another embodiment of the present invention to a different connection between a system load and a battery. Compared with FIGS. 3 and 4, the present embodiment adds error amplifiers 55 and 56 to accurately control the switching power supply 5a and the charge management circuit 5b, respectively. Other details similar to those of the third and fourth embodiments will not be repeated.

As shown in Fig. 8, the power supply system 50 includes a switching power supply 5a, a charge management circuit 5b, a battery Batt, a PMOS transistor 27, and a path selection circuit 3c. The multiplexer 32 in the path selection circuit 3c selects to transmit the error signal Comp3 to the error amplifier 55 or 56. The error amplifier 55 compares the error signal Comp3 and the reference voltage Vref5 to output the error signal Comp5, and the adder 34 adds the total error signals Comp1 and Comp5 to the PWM signal generator 12. Similarly, the error amplifier 56 compares the error signal Comp3 and the reference voltage Vref6 to output the error signal Comp6, and the adder 25 adds the total error signals Comp2 and Comp6 to the charge controller 22. The difference between the circuit of FIG. 8 and the circuit of FIG. 3 is that the information Comp3 representing the charging current of the battery Batt is not input to the adder 25 or 34 by the same value, but is compared with the reference voltage Vref5 or the reference voltage Vref6 to generate an error signal. The Comp5 or COmp6 is input to the adder 25 or 34, so that the switching circuit 14 or the PMOS transistor 27 can be controlled more accurately.

Compared with FIG. 8, the system load in the power supply system 60 in FIG. 9 is connected to the battery Batt by the sensing resistor RS, and the PMOS transistor 27 is not disposed therebetween, so the charging controller 22 outputs the pin of the signal PPCTRL. P is grounded, and the detection signal outputted by the detection signal generator 33 generates a different voltage at the output node PPCTRL of the charge controller 22 according to whether or not the PMOS transistor 27 is provided. Therefore, after the judgment of the comparator 31, the multiplexer 32 to select the appropriate path. Further, the error amplifiers (11, 55), the adder 34, and the PWM signal generator 12 constitute a switch control circuit 15'.

In an embodiment, the switch control circuit 15', the switch circuit 14, the error amplifiers (11, 21, 23, 24, 55, 56), the charge controller 22, the adders (25, 34), and the path selection circuit 3c may Integrated into a chip or a multi-purpose power management device 5d, and the chip or device can be adapted to the application example of the battery Batt connected to the output terminal Vout by the PMOS transistor 27 and the sensing resistor RS in FIG. It may be suitable for an application example in which the battery Batt is connected to the output terminal Vout by the sensing resistor RS in FIG.

The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. In the same spirit of the invention, various equivalent changes can be conceived by those skilled in the art. For example, if the charging current is sensed between the output terminal Vout and the battery Batt and the charging current of the Batt is directly set (the output terminal Vout is directly connected to the battery Batt), the configuration of the multi-purpose power supply of the present invention can still be applied. The device 3d or 5d only needs to ground or float the input of the error amplifier 24. Therefore, the scope of the invention should be construed as covering the above and all other equivalents.

1a, 3a, 5a. . . Switching power supply

2a, 3b, 5b. . . Charging management circuit

2d. . . Power management device

3c. . . Path selection circuit

3d, 5d. . . Multi-purpose power management unit

10, 20. . . Power supply system

11. . . Error amplifier

12. . . PWM signal generator

13. . . Feedback circuit

14. . . Switch circuit

15, 15’. . . Switch control circuit

16. . . Error amplifier

21, 22, 23, 24, 31. . . Error amplifier

25. . . Adder

26. . . Feedback circuit

27. . . PMOS transistor

30, 40, 50, 60. . . Power supply system

31. . . Comparators

32. . . Multiplexer

33. . . Detection signal generator

34. . . Adder

55, 56. . . Error amplifier

Batt. . . battery

Comp1～Comp6. . . Error signal

FB1, FB2. . . Feedback signal

L. . . inductance

P. . . Pin

PPCTRL. . . Signal

Q1. . . Upper bridge transistor

Q2. . . Lower bridge transistor

R1 ~ R4. . . resistance

RS. . . Sense resistor

SW. . . switch

Vin. . . Input voltage

Vout. . . The output voltage

Vbatt. . . Voltage

Vref1～Vref6. . . Reference voltage

Figure 1 shows a schematic diagram of a prior art power supply system.

Figure 2 shows a schematic diagram of another prior art power supply system.

Fig. 3 is a view showing a schematic diagram of a multi-purpose power management apparatus according to an embodiment of the present invention applied to a power supply system.

Fig. 4 is a view showing the application of the multipurpose power management device of the present invention to a power supply system.

Fig. 5 shows another embodiment of the path selecting circuit 3c.

6A-6B illustrate two embodiments of the detection signal generator 33.

FIGS. 7A-7B illustrate two other embodiments of the detection signal generator 33.

Figure 8 is a diagram showing a multi-purpose power management device according to another embodiment of the present invention applied to a power supply system.

Fig. 9 is a view showing the application of the multipurpose power management apparatus of the present invention to a power supply system.

11. . . Error amplifier

12. . . PWM signal generator

13. . . Feedback circuit

14. . . Switch circuit

15. . . Switch control circuit

21, 22, 23, 24, 31. . . Error amplifier

25. . . Adder

26. . . Feedback circuit

27. . . PMOS transistor

30. . . Power supply system

31. . . Comparators

32. . . Multiplexer

33. . . Detection signal generator

34. . . Adder

3a. . . Switching power supply

3b. . . Charging management circuit

3c. . . Path selection circuit

3d. . . Multi-purpose power management unit

Batt. . . battery

FB1, FB2. . . Feedback signal

Comp1~Comp3. . . Error signal

L. . . inductance

P. . . Pin

PPCTRL. . . Signal

Q1. . . Upper bridge transistor

Q2. . . Lower bridge transistor

R1 ~ R4. . . resistance

RS. . . Sense resistor

Vin. . . Input voltage

Vout. . . The output voltage

Vbatt. . . Voltage

Vref1～Vref4. . . Reference voltage

Claims (14)

A multi-purpose power management device for controlling power conversion from input power to output power and charging of a battery from output power, the multi-purpose power management device comprising: a switching circuit comprising at least one first power transistor; a switch control circuit for generating a control signal for controlling the power transistor to control power conversion from the input power to the output power; a charge management circuit for controlling the output power to charge the battery; and a path selection circuit for Determining whether to use the charging management circuit to control charging of the battery; wherein when the output power and the battery are connected by a second power transistor, the path selecting circuit selects the charging management circuit to operate the second power transistor To control charging of the battery; when the output power and the battery are not connected by a second power transistor, the path selection circuit does not select the charging management circuit to control charging of the battery. The multi-purpose power management device of claim 1, wherein the path selection circuit selects information about a battery charging current when the output power and the battery are not connected by a second power transistor. The switch control circuit is granted. The multi-purpose power management device of claim 1, wherein the path selection circuit comprises a multiplexer that determines whether to use the charging management circuit to control charging of the battery according to an external setting signal. The multi-purpose power management device of claim 1, wherein the charging management circuit generates an output signal, which is output from a pin, and wherein the path selection circuit comprises: a detection signal generator, the detection signal generator generates a detection signal output from the pin to generate a detection voltage; a comparator for comparing the detection voltage with a reference voltage; and a multiplexer And determining, according to the output of the comparator, whether to use the charging management circuit to control charging of the battery. The multi-purpose power management device of claim 1, wherein the charging management circuit comprises a first error amplifier, the first error amplifier generating a first error signal according to information about a battery charging current, and the path The selection circuit determines to transmit the first error signal to the switch control circuit or the charge management circuit. The multi-purpose power management device of claim 5, wherein the switch control circuit comprises: a second error amplifier, comparing the feedback signal related to the output power with a second reference voltage to generate a second error a signal, the adder receives the second error signal, and when the path selection circuit determines to transmit the first error signal to the switch control circuit, the second error signal and the first error signal are added together, otherwise And summing the second error signal and the first error signal; and the pulse width modulation controller generates a switching signal for controlling the first power transistor according to an output of the adder. The multi-purpose power management device of claim 5, wherein the switch control circuit comprises: a second error amplifier, comparing the feedback signal related to the output power with a second reference voltage to generate a second error a third error amplifier, when the path selection circuit determines to transmit the first error signal to the switch control circuit, the first error signal and a third parameter Comparing the voltage comparison to generate a third error signal; an adder summing the second error signal and the output of the third error amplifier; and a pulse width modulation controller generating a control according to the output of the adder Power transistor switching signal. The multi-purpose power management device of claim 5, wherein the charge management circuit comprises: a second error amplifier, comparing the feedback signal related to the battery voltage with a second reference voltage to generate a second error a signal, the adder receives the second error signal, and when the path selection circuit determines to transmit the first error signal to the charge management circuit, the second error signal and the first error signal are added together, otherwise And summing the second error signal and the first error signal; and the charging controller generates a signal for controlling the second power transistor according to the output of the adder. The multi-purpose power management device of claim 5, wherein the switch control circuit comprises: a second error amplifier, comparing a feedback signal related to a battery voltage with a second reference voltage to generate a second error a third error amplifier, when the path selection circuit determines to transmit the first error signal to the charge management circuit, comparing the first error signal with a third reference voltage to generate a third error signal; And summing the second error signal and the output of the third error amplifier; and the charging controller generates a signal for controlling the second power transistor according to the output of the adder. A charging path control circuit selects at least one control loop according to an output power and a connection relationship between the batteries, the charging path control circuit includes: a charging management circuit for controlling the output power to charge the battery; and a path Selecting a circuit, determining whether to use the charging management circuit to control charging of the battery according to the output power and whether a power transistor is disposed between the batteries; wherein the output power is converted by an input power through a switching power supply And when the output power and the power transistor are disposed between the batteries, the path selection circuit returns information about the battery charging current to the charging management circuit, and when the output power and the battery are not provided with power In the case of a crystal, the path selection circuit returns information about the battery charging current to the switching power supply. The charging path control circuit of claim 10, wherein the charging management circuit generates an output signal, which is output from a pin, and wherein the path selecting circuit comprises: a detecting signal generator, the detecting signal The generator generates a detection signal from the pin output to generate a detection voltage; a comparator compares the detection voltage with a reference voltage; and a multiplexer determines whether to use the output according to the output of the comparator A charge management circuit controls the charging of the battery. A charging path control method includes: converting an input power into an output power; charging a battery from the output power via a charging path; detecting whether a power transistor is disposed on the charging path; a power transistor to control the power transistor Controlling charging of the battery; and when a power transistor is not provided on the charging path, controlling the conversion of the input power and the output power to control charging of the battery. The charging path control method according to claim 12, further comprising: detecting a current on the charging path to generate information about a charging current of the battery; and using a power transistor when the charging path is provided, using the information The power transistor is controlled by feedback; and when a power transistor is not disposed on the charging path, the information is used to control the conversion of the input power and the output power. The charging path control method of claim 12, wherein the step of detecting whether a power transistor is disposed on the charging path comprises: providing a pin, the pin being connected to a gate of the power transistor Or grounding; generating a detection signal from the pin output to generate a detection voltage; and comparing the detection voltage with a reference voltage to determine whether the power transistor is provided.