Standby power supply circuit and control method thereof

Abstract

The invention discloses a standby power supply circuit and a control method thereof, and relates to a power supply circuit, the standby power supply circuit comprises a first interface, at least one second interface, an input and output loop, a DC conversion circuit, a control unit and a standby power supply; the first interface is connected with the input end of the input and output loop, and the at least one second interface is connected with the output end of the input and output loop; the first end of the direct current conversion circuit is connected with the standby power supply, and the second end of the direct current conversion circuit is connected with the input and output loop; the control unit is respectively connected with the first interface, the at least one second interface, the input / output loop and the direct current conversion circuit; the control unit controls the operation states of the input / output loop and the DC conversion circuit according to the access state of the first interface and the connection state of the at least one second interface.

Description

Technical Field

[0001] The present application relates to a power supply circuit, and in particular, to a backup power supply circuit and a control method thereof. Background Art

[0002] A traditional large UPS (uninterruptible power supply) is generally powered by AC (alternating current) output. For an average household, important uninterruptible power devices are often small devices with low power consumption, such as monitoring and routers. Obviously, purchasing a traditional large UPS is too expensive and overkill. In this case, a small UPS can be used.

[0003] However, small UPS usually only contains two main circuit parts: one is the charging circuit from the input power to the battery, and the other is the power supply circuit from the battery to the output device. This means that when the UPS system is connected to the power supply and the load device at the same time, it will charge the internal battery while the internal battery supplies power to the external load. This simultaneous charging and discharging process of the internal battery will accelerate the aging process of the UPS battery to a certain extent, thereby shortening its service life.

[0004] This section is intended to provide a background or context to the embodiments of the present application as recited in the claims. No admission is made that the description herein is prior art by inclusion in this section. Summary of the invention

[0005] The purpose of the present application is to provide a backup power supply circuit and a control method thereof, which can at least solve one of the above-mentioned technical problems existing in the current backup power supply circuit and a control method thereof.

[0006] An embodiment of the present application provides a backup power supply circuit, comprising: a first interface, at least one second interface, an input-output circuit, a DC conversion circuit, a control unit and a backup battery; wherein the first interface is connected to the input end of the input-output circuit, and the at least one second interface is connected to the output end of the input-output circuit; the first end of the DC conversion circuit is connected to the backup battery, and the second end of the DC conversion circuit is connected to the input-output circuit; the control unit is respectively connected to the first interface, the at least one second interface, the input-output circuit and the DC conversion circuit, and the control unit detects the access status of the first interface and the connection status of the at least one second interface, and controls the operating status of the input-output circuit and the DC conversion circuit according to the access status of the first interface and the connection status of the at least one second interface.

[0007] In some embodiments, the first interface includes a first DC socket, the first DC socket includes a first positive pin, a first negative pin and a first detection pin. When the first DC socket is not connected to an input power supply, the first detection pin is short-circuited with the first negative pin. When the first DC socket is connected to an input power supply, the first DC line of the input power supply will elastically push the first detection pin open, so that the first detection pin is separated from the first negative pin; the second interface includes a second DC socket, the second DC socket includes a second positive pin, a second negative pin and a second detection pin. When the second DC socket is not connected to a load, the second detection pin is short-circuited with the second negative pin. When the second DC socket is connected to a load, the second DC line of the load will elastically push the second detection pin open, so that the second detection pin is separated from the second negative pin.

[0008] In some embodiments, the control unit includes an input detection pin and an output detection pin, wherein the input detection pin is connected to the first detection pin, the number of the output detection pins is greater than or equal to the number of the second interfaces, and each second detection pin of the second interface is connected to one of the output detection pins.

[0009] In some embodiments, it also includes a load sampling resistor, the number of which is greater than or equal to the number of the second interfaces, and the second negative pin of each of the second interfaces is grounded through one of the load sampling resistors; the control unit also includes a current output detection pin, the number of which is greater than or equal to the number of the second interfaces, and the second negative pin of each of the second interfaces is connected to one of the current output detection pins.

[0010] In some embodiments, a charging sampling resistor is further included, and the negative electrode of the backup battery is grounded through the charging sampling resistor; the control unit also includes a charging current detection pin, and the charging current detection pin is connected to the negative electrode of the backup battery.

[0011] In some embodiments, the input-output loop includes a first branch and a second branch connected in parallel, and the second end of the DC conversion circuit is connected to the second branch.

[0012] In some embodiments, the first branch includes a first switch tube, the second branch includes a second switch tube and a third switch tube, and the control unit includes a first enable pin, a second enable pin and a third enable pin; wherein, the first end of the first switch tube is connected to the first positive pin, the second end of the first switch tube is connected to the second positive pin of each second interface, and the third end of the first switch tube is connected to the first enable pin of the control unit; the first end of the second switch tube is connected to the first positive pin, the second end of the second switch tube is connected to the first end of the third switch tube, the second end of the third switch tube is connected to the second positive pin of each second interface, the third end of the second switch tube is connected to the second enable pin of the control unit, and the third end of the third switch tube is connected to the third enable pin of the control unit; the second end of the DC conversion circuit is connected to the second end of the second switch tube.

[0013] In some embodiments, the DC conversion circuit includes a buck-boost circuit, a boost circuit, or a buck circuit.

[0014] In some embodiments, the buck-boost circuit includes a first capacitor, a fourth switch tube, a fifth switch tube, a first inductor, a sixth switch tube, a seventh switch tube and a second capacitor; the control unit includes a first output pin for outputting a high level of a first pulse modulation signal, a second output pin for outputting a low level of the first pulse modulation signal, a third output pin for outputting a high level of a second pulse modulation signal and a fourth output pin for outputting a low level of the second pulse modulation signal; wherein, the first end of the first capacitor is connected to the second end of the second switch tube, and the second end of the first capacitor is grounded; the first end of the fourth switch tube is connected to the first end of the first capacitor, the second end of the fourth switch tube is connected to the first end of the first inductor, and the first end of the fourth switch tube is connected to the first end of the first inductor. The three ends are connected to the first output pin of the control unit; the first end of the fifth switch tube is connected to the first end of the first inductor, the second end of the fifth switch tube is grounded, and the third end of the fifth switch tube is connected to the second output pin of the control unit; the first end of the sixth switch tube is connected to the second end of the first inductor, the second end of the sixth switch tube is connected to the positive electrode of the backup battery, and the third end of the sixth switch tube is connected to the third output pin of the control unit; the first end of the seventh switch tube is connected to the first end of the sixth switch tube, the second end of the seventh switch tube is grounded, and the third end of the seventh switch tube is connected to the fourth output pin of the control unit; the first end of the second capacitor is connected to the positive electrode of the backup battery, and the second end of the second capacitor is grounded.

[0015] In some embodiments, the boost circuit includes a third capacitor, an eighth switch tube, a ninth switch tube, a second inductor and a fourth capacitor; the control unit includes a first output pin for outputting a high level of a first pulse modulation signal and a second output pin for outputting a low level of the first pulse modulation signal; wherein the first end of the third capacitor is connected to the second end of the second switch tube, and the second end of the third capacitor is grounded; the first end of the eighth switch tube is connected to the first end of the third capacitor, the second end of the eighth switch tube is connected to the first end of the second inductor, and the third end of the eighth switch tube is connected to the first output pin of the control unit; the first end of the ninth switch tube is connected to the second end of the eighth switch tube, the second end of the ninth switch tube is grounded, and the third end of the ninth switch tube is connected to the second output pin of the control unit; the second end of the second inductor is connected to the positive electrode of the backup battery; the first end of the fourth capacitor is connected to the positive electrode of the backup battery, and the second end of the fourth capacitor is grounded.

[0016] In some embodiments, the step-down circuit includes a fifth capacitor, a third inductor, a tenth switch tube, an eleventh switch tube and a sixth capacitor; the control unit includes a third output pin for outputting a high level of a second pulse modulation signal and a fourth output pin for outputting a low level of the second pulse modulation signal; wherein the first end of the fifth capacitor is connected to the second end of the second switch tube, and the second end of the fifth capacitor is grounded; the first end of the third inductor is connected to the first end of the fifth capacitor, the second end of the third inductor is connected to the first end of the tenth switch tube, the second end of the tenth switch tube is connected to the positive electrode of the backup battery, and the third end of the tenth switch tube is connected to the third output pin of the control unit; the first end of the eleventh switch tube is connected to the first end of the tenth switch tube, the second end of the eleventh switch tube is grounded, and the third end of the eleventh switch tube is connected to the fourth output pin of the control unit; the first end of the sixth capacitor is connected to the positive electrode of the backup battery, and the second end of the sixth capacitor is grounded.

[0017] An embodiment of the present application further provides a control method for a backup power supply circuit. Based on the backup power supply circuit described in any of the above embodiments, the method includes:

[0018] Detecting a connection status of the first interface and a connection status of the at least one second interface;

[0019] The operation states of the input-output circuit and the DC conversion circuit are controlled according to the connection state of the first interface and the connection state of the at least one second interface.

[0020] In some embodiments, controlling the operation state of the input / output circuit and the DC conversion circuit according to the connection state of the first interface and the connection state of the at least one second interface includes:

[0021] If the first interface is not connected to the input power supply and all the second interfaces are not connected to the load, the input-output circuit and the DC conversion circuit are controlled to be turned off;

[0022] If the first interface is not connected to an input power source and at least one of the second interfaces is connected to a load, the DC conversion circuit is controlled to be turned on, and the part of the input-output loop connected between the DC conversion circuit and the second interface is controlled to be turned on, so that the backup battery supplies power to the load connected to the at least one second interface;

[0023] If the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source first supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged;

[0024] If the first interface is connected to an input power source and all the second interfaces are not connected to a load, the DC conversion circuit is controlled to be turned on, and the input-output loop is controlled to be partially turned on between the first interface and the DC conversion circuit, so that the input power source charges the backup battery.

[0025] In some embodiments, the method further comprises:

[0026] Real-time detection of the current output by the at least one second interface to the load and the charging current of the backup battery;

[0027] Correspondingly, if the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source preferentially supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged, including:

[0028] If the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, controlling the input-output loop to be partially conductive between the first interface and the second interface;

[0029] Determine the charging current for the backup battery according to the current output to the load by the second interface connected to the load and the maximum operating current of the input power supply detected in real time;

[0030] Controlling the partial conduction of the input-output loop between the first interface and the DC conversion circuit, and controlling the DC conversion circuit to be turned on, so that the input power source charges the backup battery with the charging current;

[0031] According to the charging current of the backup battery detected in real time, it is determined whether the backup battery is fully charged, and when the backup battery is fully charged, the DC conversion circuit is controlled to be turned off, so that the backup battery is powered off.

[0032] The backup power supply circuit and control method provided by the embodiment of the present application include an input-output circuit and a DC conversion circuit, which can detect the connection status of the first interface and the connection status of the second interface respectively through a control unit, and control the operation status of the input-output circuit and the DC conversion circuit according to the connection status of the first interface and the connection status of the second interface. In this way, when the first interface is connected to the input power supply and the second interface is connected to the load, the input-output circuit and the DC conversion circuit are controlled to be turned on through the control unit, so that the input power supplies the load through the input-output circuit, and the backup battery is charged through the input-output circuit and the DC conversion circuit. That is to say, the backup power supply circuit provided by the embodiment of the present application can directly supply power to the load with the input power supply first when the input power supply and the load are connected at the same time, and if the input power supply has excess power, the backup battery is charged with the excess power, thereby avoiding the backup battery from being charged and discharged at the same time when the input power supply and the load are connected at the same time, thereby extending the life of the backup battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic diagram of the structure of a backup power supply circuit provided in an embodiment of the present application.

[0035] Figure 2 A schematic diagram of the structure of another backup power supply circuit provided in an embodiment of the present application.

[0036] Figure 3 A schematic diagram of the structure of another backup power supply circuit provided in an embodiment of the present application.

[0037] Figure 4 A flowchart of a method for controlling a backup power supply circuit provided in an embodiment of the present application.

[0038] Figure 5A schematic diagram of the switching logic between various working states of a backup power supply circuit provided in an embodiment of the present application.

[0039] Figure 6 A partial flow chart of a method for controlling a backup power supply circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] With reference to the following description and accompanying drawings, the specific embodiments of the present application are disclosed in detail, indicating the way in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope. Within the scope of the spirit and clauses of the appended claims, the embodiments of the present application include many changes, modifications and equivalents.

[0042] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0043] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0044] In order to solve at least one of the above problems existing in the prior art, in a first aspect, the present application provides a backup power supply circuit, such as Figure 1As shown, the backup power supply circuit 001 includes a first interface DC1, at least one second interface DC2, an input-output circuit 10, a DC conversion circuit (DC-DC circuit) 20, a control unit 30 and a backup battery BT; wherein the first interface DC1 is connected to the first end 10a of the input-output circuit 10, and the at least one second interface DC2 is connected to the output end 10b of the input-output circuit 10; the first end 20a of the DC conversion circuit 20 is connected to the backup battery BT, and the second end 20b of the DC conversion circuit 20 is connected to the input-output circuit 10; the control unit 30 is respectively connected to the first interface DC1, the at least one second interface DC2, the input-output circuit 10 and the DC conversion circuit 20, and the control unit 30 detects the connection status of the first interface DC1 and the connection status of the at least one second interface DC2, and controls the operation status of the input-output circuit 10 and the DC conversion circuit 20 according to the connection status of the first interface DC1 and the at least one second interface DC2.

[0045] It can be understood that the first interface DC1 is the input interface of the backup power supply circuit 001, which is used to connect the input power supply; the second interface DC2 is the output interface of the backup power supply circuit 001, which is used to connect the load. In an embodiment of the present invention, there may be more than one second interface DC2. When the backup power supply circuit 001 includes two or more second interfaces DC2, the connection method of each second interface DC2 and the input and output circuit 10 and the control unit 30 is similar, which will not be repeated here.

[0046] The connection state of the first interface DC1 includes no input power supply and input power supply, and the connection state of each second interface DC2 includes no load and load; the operation state of the input-output circuit 10 includes on and off, and similarly, the operation state of the DC conversion circuit 20 includes on and off. The control unit 30 has two functions of control and power conversion. The control unit 30 can be an editable device such as a single-chip microcomputer, a DSP (digital signal processor) or an FPGA (field programmable gate array), or the control unit 30 can include a controller and a dedicated analog power management chip, and the controller and the dedicated analog power management chip respectively realize the two functions of control and power conversion.

[0047] The backup power supply circuit 001 provided in the embodiment of the present application includes an input-output circuit 10 and a DC conversion circuit 20, and can detect the connection state of the first interface DC1 and the connection state of the second interface DC2 respectively through the control unit 30, and control the operation state of the input-output circuit 10 and the DC conversion circuit 20 according to the connection state of the first interface DC1 and the connection state of the second interface DC2. In this way, when the first interface DC1 is connected to the input power supply and the second interface DC2 is connected to the load, the control unit 30 controls the input-output circuit 10 and the DC conversion circuit 20 to be turned on, so that the input power supplies the load through the input-output circuit 10, and charges the backup battery BT through the input-output circuit 10 and the DC conversion circuit 20. That is to say, the backup power supply circuit 001 provided in the embodiment of the present application can, when the input power supply and the load are connected at the same time, the input power supply directly supplies power to the load through the input-output circuit 10, and if the input power supply has excess power, the backup battery BT is charged with the excess power, thereby avoiding the backup battery BT from being charged and discharged at the same time when the input power supply and the load are connected at the same time, thereby extending the life of the backup battery BT.

[0048] In addition, the current method of detecting device access and removal is often through the impedance of the device itself. Specifically, a weak output is designed and the voltage change of the weak output is detected to achieve load access identification. Removal depends on the output current. When the current is lower than the threshold point, the device is considered to have been removed and the output is turned off. It can be seen that for devices with very large non-working impedance, the access may not be identified due to the small change in the weak output voltage. In addition, for devices that work intermittently or have very low working currents, removal detection may be triggered incorrectly, causing the device to not work properly.

[0049] In this regard, the embodiment of the present application also provides a device access and removal detection circuit to solve the above-mentioned problems existing in the current method for detecting device access and removal. Figure 1As shown, the first interface DC1 includes a first DC (direct current) socket, the first DC socket includes a first positive pin 1a, a first negative pin 1b and a first detection pin 1c. When the first DC socket is not connected to the input power supply, the first detection pin 1c is short-circuited with the first negative pin 1b. When the first DC socket is connected to the input power supply, the first DC line of the input power supply will push the first detection pin 1c with elasticity to make the first detection pin 1c separate from the first negative pin 1b. Similarly, the second interface DC2 includes a second DC socket, the second DC socket includes a second positive pin 2a, a second negative pin 2b and a second detection pin 2c. When the second DC socket is not connected to the load, the second detection pin 2c is short-circuited with the second negative pin 2b. When the second DC socket is connected to the load, the second DC line of the load will push the second detection pin 2c with elasticity to make the second detection pin 2c separate from the second negative pin 2b.

[0050] Specifically, the DC socket provided in this embodiment has a detection pin in addition to the positive pin and the negative pin. When the DC line of the input power / load is not connected to the socket, the detection pin is short-circuited with the negative pole. When the DC line is connected to the socket, the wire head pushes the elastic detection pin away from the negative pin. This ensures that there is no false detection when connecting and removing the device, and allows the device to work intermittently or with very low current.

[0051] like Figure 1 As shown, in some embodiments, the control unit 30 includes an input detection pin IN_DET and an output detection pin OUT_DET, wherein the input detection pin IN_DET is connected to the first detection pin 1c, the number of the output detection pins OUT_DET is greater than or equal to the number of the second interfaces DC2, and each second detection pin 2c of the second interface DC2 is connected to one of the output detection pins OUT_DET. In other words, for a backup power supply circuit 001 having at least one second interface DC2, it is necessary to have at least the same number of output detection pins OUT_DET as the number of the second interfaces DC2, so that the second detection pin 2c of each second interface DC2 is connected to one of the output detection pins OUT_DET, so that the control unit 30 can detect the load access status of each second interface DC2.

[0052] Specifically, Figure 1For example, the backup power circuit 001 can be connected to the internal power supply VCC and the first detection pin 1c / second detection pin 2c through a relatively large resistance resistor R1 / R2. When the wire is connected, the first detection pin 1c / second detection pin 2c is pulled down to a low level by the negative electrode. When the wire is connected, the first detection pin 1c / second detection pin 2c is separated from the negative electrode and suspended in the air to a high level. By detecting the level change of the first detection pin 1c / second detection pin 2c, it can be known whether the input power / load is connected or removed.

[0053] like Figure 1 As shown, in some embodiments, the backup power supply circuit 001 further includes a load sampling resistor R6, the number of which is greater than or equal to the number of the second interfaces DC2, and the second negative pin 2b of each second interface DC2 is grounded through a load sampling resistor R6; the control unit 30 further includes a current output detection pin IOUT, the number of which is greater than or equal to the number of the second interfaces DC2, and the second negative pin 2b of each second interface DC2 is connected to a current output detection pin IOUT. In other words, for the backup power supply circuit 001 having at least one second interface DC2, at least the number of load sampling resistors R6 equal to the number of the second interfaces DC2 is required, so that the second negative pin 2b of each second interface DC2 can be grounded through a load sampling resistor R6; in addition, the control unit 30 also needs to have at least the number of current output detection pins IOUT equal to the number of the second interfaces DC2, so that the second negative pin 2b of each second interface DC2 can be connected to a current output detection pin IOUT, thereby enabling the control unit 30 to detect the load current of each second interface DC2.

[0054] like Figure 1 As shown, the backup power supply circuit 001 further includes a charging sampling resistor R5, and the negative electrode 1 of the backup battery BT is grounded through the charging sampling resistor R5; the control unit 30 further includes a charging current detection pin ICHG, and the charging current detection pin ICHG is connected to the negative electrode 1 of the backup battery BT. The charging current detection pin ICHG is used to set and monitor the charging current to ensure the safety and efficiency of the battery charging process.

[0055] like Figure 1 As shown, in some embodiments, the input-output circuit 10 includes a first branch 11 and a second branch 12 connected in parallel, and the second end 20 b of the DC conversion circuit 20 is connected to the second branch 12 .

[0056] like Figure 1As shown, in some embodiments, the first branch 11 includes a first switch tube Q1, the second branch 12 includes a second switch tube Q2 and a third switch tube Q3, and the control unit 30 includes a first enable pin BY_EN, a second enable pin IN_EN and a third enable pin OUT_EN; wherein, the first end of the first switch tube Q1 is connected to the first positive electrode pin 1a, the second end of the first switch tube Q1 is connected to the second positive electrode pin 2a of each second interface DC2, and the third end of the first switch tube Q1 is connected to the first enable pin BY_EN of the control unit 30. The first end of the second switch tube Q2 is connected to the first positive pin 1a, the second end of the second switch tube Q2 is connected to the first end of the third switch tube Q3, the second end of the third switch tube Q3 is connected to the second positive pin 2a of each second interface DC2, the third end of the second switch tube Q2 is connected to the second enable pin IN_EN of the control unit 30, and the third end of the third switch tube Q3 is connected to the third enable pin OUT_EN of the control unit 30; the second end 20b of the DC conversion circuit 20 is connected to the second end of the second switch tube Q2.

[0057] In some embodiments, the DC conversion circuit 20 includes a buck-boost circuit, a boost circuit, and a buck circuit. Figure 1 The DC conversion circuit 20 shown in the figure uses a buck-boost circuit to achieve power conversion. In addition, for backup power circuit products in which it is known that the backup battery voltage is always higher than the device power supply voltage, a BUCK circuit can be used. For backup power circuit products in which it is known that the backup battery voltage is always lower than the device power supply voltage, a BOOST circuit can be used. The control method of the backup power circuit can be the same.

[0058] like Figure 1As shown, in some embodiments, the DC conversion circuit 20 includes a buck-boost circuit, which may include a first capacitor C1, a fourth switch tube Q4, a fifth switch tube Q5, a first inductor L1, a sixth switch tube Q6, a seventh switch tube Q7 and a second capacitor C2, and the control unit 30 includes a first output pin PWM1H for outputting a high level of a first pulse modulation signal, a second output pin PWM1L for outputting a low level of the first pulse modulation signal, a third output pin PWM2H for outputting a high level of a second pulse modulation signal and a fourth output pin PWM2L for outputting a low level of the second pulse modulation signal; wherein the first end of the first capacitor C1 is connected to the second end of the second switch tube Q2, and the second end of the first capacitor C1 is grounded; the first end of the fourth switch tube Q4 is connected to the first end of the first capacitor C1, the second end of the fourth switch tube Q4 is connected to the first end of the first inductor L1, and the fourth switch The third end of the switch Q4 is connected to the first output pin PWM1H of the control unit 30; the first end of the fifth switch Q5 is connected to the first end of the first inductor L1, the second end of the fifth switch Q5 is grounded, and the third end of the fifth switch Q5 is connected to the second output pin PWM1L of the control unit 30; the first end of the sixth switch Q6 is connected to the second end of the first inductor L1, the second end of the sixth switch Q6 is connected to the positive electrode 2 of the backup battery BT, and the third end of the sixth switch Q6 is connected to the third output pin PWM2H of the control unit 30; the first end of the seventh switch Q7 is connected to the first end of the sixth switch Q6, the second end of the seventh switch Q7 is grounded, and the third end of the seventh switch Q7 is connected to the fourth output pin PWM2L of the control unit 30; the first end of the second capacitor C2 is connected to the positive electrode 2 of the backup battery BT, and the second end of the second capacitor C2 is grounded.

[0059] like Figure 2As shown, in some embodiments, the DC conversion circuit 20 includes a boost circuit, which includes a third capacitor C3, an eighth switch tube Q8, a ninth switch tube Q9, a second inductor L2 and a fourth capacitor C4; the control unit 30 includes a first output pin PWM1H for outputting a high level of a first pulse modulation signal and a second output pin PWM1L for outputting a low level of the first pulse modulation signal; wherein the first end of the third capacitor C3 is connected to the second end of the second switch tube Q2, and the second end of the third capacitor C3 is grounded; the first end of the eighth switch tube Q8 is connected to the first end of the third capacitor C3, The second end of the eighth switch tube Q8 is connected to the first end of the second inductor L2, and the third end of the eighth switch tube Q8 is connected to the first output pin PWM1H of the control unit 30; the first end of the ninth switch tube Q9 is connected to the second end of the eighth switch tube Q8, the second end of the ninth switch tube Q9 is grounded, and the third end of the ninth switch tube Q9 is connected to the second output pin PWM1L of the control unit 30; the second end of the second inductor L2 is connected to the positive electrode 2 of the backup battery BT; the first end of the fourth capacitor C4 is connected to the positive electrode 2 of the backup battery BT, and the second end of the fourth capacitor C4 is grounded.

[0060] like Figure 3 As shown, in some embodiments, the DC conversion circuit 20 includes a step-down circuit, which includes a fifth capacitor C5, a third inductor L3, a tenth switch tube Q10, an eleventh switch tube Q11 and a sixth capacitor C6; the control unit 30 includes a third output pin PWM2H for outputting a high level of the second pulse modulation signal and a fourth output pin PWM2L for outputting a low level of the second pulse modulation signal; wherein the first end of the fifth capacitor C5 is connected to the second end of the second switch tube Q2, and the second end of the fifth capacitor C5 is grounded; the first end of the third inductor L3 is connected to the first end of the fifth capacitor C5, and the third The second end of the inductor L3 is connected to the first end of the tenth switch tube Q10, the second end of the tenth switch tube Q10 is connected to the positive electrode 2 of the backup battery BT, and the third end of the tenth switch tube Q10 is connected to the third output pin PWM2H of the control unit 30; the first end of the eleventh switch tube Q11 is connected to the first end of the tenth switch tube Q10, the second end of the eleventh switch tube Q11 is grounded, and the third end of the eleventh switch tube Q11 is connected to the fourth output pin PWM2L of the control unit 30; the first end of the sixth capacitor C6 is connected to the positive electrode 2 of the backup battery BT, and the second end of the sixth capacitor C6 is grounded.

[0061] In any of the above embodiments, NMOS (N-type metal oxide semiconductor) can be used as a switch tube. In addition, other transistors can also be used in applications to achieve similar switching functions, such as PMOS (P-type metal oxide semiconductor), thyristor, triode, etc.

[0062] Based on the same inventive concept, an embodiment of the present application also provides a control method for a backup power supply circuit, based on the backup power supply circuit described in any of the above embodiments. Figure 4 is a flow chart of a control method for a backup power supply circuit provided in an embodiment of the present application, such as Figure 4 As shown, the method includes:

[0063] S1. Detecting a connection status of the first interface and a connection status of the at least one second interface;

[0064] S2. Controlling the operation status of the input / output circuit and the DC conversion circuit according to the connection status of the first interface and the connection status of the at least one second interface.

[0065] The control method of the backup power circuit provided in the embodiment of the present application is shown in Figure 1 When the first interface DC1 is connected to the input power supply and the second interface DC2 is connected to the load, the control unit 30 can control the input-output circuit 10 and the DC conversion circuit 20 to be turned on, so that the input power supplies the load through the input-output circuit 10, and the backup battery BT is charged through the input-output circuit 10 and the DC conversion circuit 20. That is to say, the backup power supply circuit 001 provided in the embodiment of the present application can, when the input power supply and the load are connected at the same time, the input power supply directly supplies power to the load through the input-output circuit 10, and if the input power supply has excess power, the excess power is used to charge the backup battery BT, thereby avoiding the backup battery BT from being charged and discharged at the same time when the input power supply and the load are connected at the same time, thereby extending the life of the backup battery BT.

[0066] In some embodiments, the above step S2 may include: if the first interface is not connected to the input power supply and all the second interfaces are not connected to the load, controlling the input-output loop and the DC conversion circuit to be turned off;

[0067] If the first interface is not connected to an input power source and at least one of the second interfaces is connected to a load, the DC conversion circuit is controlled to be turned on, and the part of the input-output loop connected between the DC conversion circuit and the second interface is controlled to be turned on, so that the backup battery supplies power to the load connected to the at least one second interface;

[0068] If the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source first supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged;

[0069] If the first interface is connected to an input power source and all the second interfaces are not connected to a load, the DC conversion circuit is controlled to be turned on, and the input-output loop is controlled to be partially turned on between the first interface and the DC conversion circuit, so that the input power source charges the backup battery.

[0070] Specifically, if Figure 5 As shown, the backup power supply circuit provided in this embodiment includes four states: standby, discharging, charging, and charging and discharging. The switching logic and conditions between the states are as follows:

[0071] When there is no load and no input power is connected, the default state is standby, at which time the input and output circuits and the DC conversion circuit stop working.

[0072] When a load line is connected alone (connected to at least one load), it enters the discharge state, at which time the DC conversion circuit is turned on, and the part of the input and output loop connected between the DC conversion circuit and the second interface is turned on, so that the backup battery supplies power to the load. After the load is removed, it returns to the standby state, and the backup power supply circuit is the same as the standby state described above.

[0073] After the input power is connected in the discharge state, it enters the charge-and-discharge state. At this time, the input-output circuit is turned on, so that the input power supply gives priority to supplying power to the load, and when there is excess power, the DC conversion circuit is turned on to charge the backup battery, and when the backup battery is fully charged, the DC conversion circuit is turned off, and the backup battery is not charged or discharged, thereby extending the battery life; and when there is no excess power, the DC conversion circuit is turned off and the backup battery is not charged.

[0074] In the charging and discharging state, all loads are removed or input power is connected in the standby state to enter the charging state. At this time, the DC conversion circuit is turned on, and the part of the input and output loop between the first interface and the DC conversion circuit is also turned on, and the backup battery is charged at full speed.

[0075] In some embodiments, the method further comprises: detecting in real time the current outputted by the at least one second interface to the load and the charging current of the backup battery; accordingly, Figure 6As shown, if the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source preferentially supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged, including:

[0076] S21, if the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, controlling the input-output loop to be partially conductive between the first interface and the second interface;

[0077] S22, determining a charging current for the backup battery according to the current output to the load by the second interface connected to the load and the maximum operating current of the input power supply detected in real time;

[0078] S23, controlling the input-output circuit to be partially turned on between the first interface and the DC conversion circuit, and controlling the DC conversion circuit to be turned on, so that the input power source charges the backup battery with the charging current;

[0079] S24. Determine whether the backup battery is fully charged according to the charging current of the backup battery detected in real time, and control the DC conversion circuit to shut down when the backup battery is fully charged, so that the backup battery is powered off.

[0080] Specifically, Figure 1 For example, when the first interface DC1 is connected to the input power supply, the input-output circuit 10 is partially turned on between the first interface DC1 and the second interface DC2, so that the input power supply supplies power to the load. In addition, the control unit 30 detects the ground voltage Viout of the load sampling resistor R6, and then calculates the actual discharge current to the load as Iout=Viout / R6; assuming that the maximum operating current of the input power supply is Imax, then as long as the charging current Ichg=Imax-Iout is ensured, it can be guaranteed that the input power supply is maximized to achieve charging and discharging at the same time. According to the above logic, in the state of charging and discharging at the same time, the input power supply is output to the load first, and the backup battery BT is charged when there is excess power. When the backup power supply circuit 001 includes two or more second interfaces DC2, the calculation method is similar when multiple second interfaces DC2 are connected to loads respectively, and it will not be repeated here.

[0081] To better understand the control method of the backup power supply circuit provided by the present application, the following is Figure 1 The control method of the backup power supply circuit provided in the present application is described in detail by taking the backup power supply circuit 001 shown as an example.

[0082] like Figure 1 As shown, the control unit 30 can be an MCU (not limited to a single-chip microcomputer, DSP, FPGA, etc.), or an MCU + an external analog chip. The connection relationship between the control unit 30 and other components of the backup power supply circuit is as follows: PWM1H is connected to the gate end (gate) of the fourth switch tube Q4, PWM1L is connected to the gate end of the fifth switch tube Q5, PWM2L is connected to the gate end of the seventh switch tube Q7, PWM2H is connected to the gate end of the sixth switch tube Q6, VI is connected to the voltage-dividing resistors R3 and R4, BY_EN is connected to the gate end of the first switch tube Q1, OUT_EN is connected to the gate end of the third switch tube Q3, OUT_DET is connected to the detection pin 2c of the interface DC2, IN_DET is connected to the detection pin 1c of the interface DC1, and IN_EN is connected to the gate end of the second switch tube Q2. The first positive pin 1a of the interface DC1 is connected to the source end (source) of the first switch tube Q1, the source end of the second switch tube Q2 and one end of the voltage-dividing resistor R3, and the first negative pin 1b is connected to the ground wire. The second positive pin 2a of the DC2 interface is connected to the source end of the third switch tube Q3 and the drain end (drain) of the first switch tube Q1, and the second negative pin 2b is connected to one end of the load sampling resistor R6.

[0083] The backup power supply circuit 001 has four states: standby, discharge, charge, and charge and discharge. The switching logic and conditions between the states are as follows:

[0084] When there is no load and the charging adapter is not connected (that is, the input power is not connected), that is, when the charging adapter is not connected, the default state is standby. At this time, OUT_EN, IN_EN and BY_EN are set to low level, the first switch tube Q1, the second switch tube Q2, and the third switch tube Q3 are turned off, PWM1H / PWM1L / PWM2H / PWM2L output low level, the fourth switch tube Q4 / the fifth switch tube Q5 / the sixth switch tube Q6 / the seventh switch tube Q7 are turned off, and the DC conversion circuit 20 stops working. Because there is no wireless material connected, the detection pins 1c and 2c of the interface DC1 and the interface DC2 are short-circuited with the negative pins 1b and 2b respectively, so OUT_DET and IN_DET are both low level at this time.

[0085] When the load line is connected alone, the second detection pin 2c in the interface DC2 is connected due to the DC male connector, and the second detection pin 2c is disconnected from the second negative pin 2b (the second detection pin 2c and the second negative pin 2b are short-circuited by default when the wireless material is connected), so OUT_DET is pulled up from a low level to a high level. After the control unit 30 detects the level change, it turns on the DC conversion circuit 20, sets OUT_EN to a high level, IN_EN and BY_EN to a low level, turns on the third switch tube Q3, and turns on the second switch tube Q2 and the first switch tube Q1; the interface DC2 outputs a preset voltage to power the load. After the load is removed, it returns to the standby state, and the states of the pins of the control unit 30 are the same as the states of the pins of the control unit 30 in the standby state described above.

[0086] After the adapter is connected in the discharge state (that is, the input power supply is connected), the backup power supply circuit 001 enters the charging and discharging state. At this time, IN_EN and BY_EN are set to high level, OUT_EN is set to low level, the second switch tube Q2, the first switch tube Q1 are turned on, and the third switch tube Q3 is turned off. Since the first switch tube Q1 is turned on, the adapter directly supplies power to the load at this time. At the same time, the control unit 30 detects that the voltage of the load sampling resistor R6 to the ground is Viout, and the actual discharge current to the load can be calculated as Iout=Viout / R6; assuming that the maximum operating current of the adapter is Imax, then as long as Ichg=Imax-Iout is ensured, it can be guaranteed that the adapter is maximized to achieve charging and discharging. According to the above logic, in the charging and discharging state, the adapter supplies power to the output load first, and charges the backup battery BT when there is excess power.

[0087] When the load is removed in the charging and discharging state or the adapter is connected in the standby state, the backup power circuit 001 enters the charging state, the second switch tube Q2 is turned on, and the third switch tube Q3 is turned off. At this time, the backup battery BT is charged at full speed. In this case, the first switch tube Q1 can be in the on state or in the off state. When the first switch tube Q1 is in the off state at this time, the first switch tube Q1 can be controlled to turn on when the output detection pin OUT_DET detects that the second interface DC2 is connected to the load.

[0088] It can be seen that the backup power supply circuit and control method provided by this embodiment can output DC power without human intervention when the device is connected and when the power is off, and at the same time, the power path management is done well to ensure the service life of the battery. Compared with the traditional UPS, the backup power supply circuit provided by this embodiment is both economical and effective.

[0089] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0090] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0091] Specific embodiments are used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core idea of ​​this application. At the same time, for those skilled in the art, according to the idea of ​​this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on this application.

Claims

1. A backup power supply circuit, characterized in that: It includes a first interface, at least one second interface, an input-output circuit, a DC conversion circuit, a control unit and a backup battery; wherein, The first interface is connected to the input end of the input-output loop, and the at least one second interface is connected to the output end of the input-output loop; The first end of the DC conversion circuit is connected to the backup battery, and the second end of the DC conversion circuit is connected to the input-output loop; The control unit is respectively connected to the first interface, the at least one second interface, the input-output circuit and the DC conversion circuit. The control unit detects the access status of the first interface and the connection status of the at least one second interface, and controls the operating status of the input-output circuit and the DC conversion circuit according to the access status of the first interface and the connection status of the at least one second interface.

2. The backup power supply circuit according to claim 1, characterized in that: The first interface includes a first DC socket, the first DC socket includes a first positive pin, a first negative pin and a first detection pin, when the first DC socket is not connected to an input power source, the first detection pin is short-circuited with the first negative pin, when the first DC socket is connected to an input power source, the first DC line of the input power source pushes the first detection pin with elasticity open, so that the first detection pin is separated from the first negative pin; The second interface includes a second DC socket, which includes a second positive pin, a second negative pin and a second detection pin. When the second DC socket is not connected to a load, the second detection pin is short-circuited with the second negative pin. When the second DC socket is connected to a load, the second DC line of the load pushes the elastic second detection pin open, so that the second detection pin is separated from the second negative pin.

3. The backup power supply circuit according to claim 2, characterized in that: The control unit includes an input detection pin and an output detection pin, wherein the input detection pin is connected to the first detection pin, the number of the output detection pins is greater than or equal to the number of the second interfaces, and each second detection pin of the second interface is connected to one of the output detection pins.

4. The backup power supply circuit according to claim 3, characterized in that: It also includes a load sampling resistor, the number of which is greater than or equal to the number of the second interfaces, and the second negative pin of each of the second interfaces is grounded through a load sampling resistor; The control unit further includes current output detection pins, the number of which is greater than or equal to the number of the second interfaces, and each second negative electrode pin of the second interface is connected to one of the current output detection pins.

5. The backup power supply circuit according to claim 4, characterized in that: It also includes a charging sampling resistor, and the negative electrode of the backup battery is grounded through the charging sampling resistor; The control unit further comprises a charging current detection pin, and the charging current detection pin is connected to the negative electrode of the backup battery.

6. The backup power supply circuit according to any one of claims 2 to 5, characterized in that: The input-output loop includes a first branch and a second branch connected in parallel, and the second end of the DC conversion circuit is connected to the second branch.

7. The backup power supply circuit according to claim 6, characterized in that: The first branch includes a first switch tube, the second branch includes a second switch tube and a third switch tube, and the control unit includes a first enable pin, a second enable pin and a third enable pin; wherein, The first end of the first switch tube is connected to the first positive pin, the second end of the first switch tube is connected to the second positive pin of each second interface, and the third end of the first switch tube is connected to the first enable pin of the control unit; The first end of the second switch tube is connected to the first positive pin, the second end of the second switch tube is connected to the first end of the third switch tube, the second end of the third switch tube is connected to the second positive pin of each second interface, the third end of the second switch tube is connected to the second enable pin of the control unit, and the third end of the third switch tube is connected to the third enable pin of the control unit; The second end of the DC conversion circuit is connected to the second end of the second switch tube.

8. The backup power supply circuit according to claim 7, characterized in that: The DC conversion circuit includes a step-up / step-down circuit, a boost circuit or a step-down circuit.

9. The backup power supply circuit according to claim 8, characterized in that: The buck-boost circuit includes a first capacitor, a fourth switch tube, a fifth switch tube, a first inductor, a sixth switch tube, a seventh switch tube and a second capacitor; the control unit includes a first output pin for outputting a high level of a first pulse modulation signal, a second output pin for outputting a low level of the first pulse modulation signal, a third output pin for outputting a high level of a second pulse modulation signal and a fourth output pin for outputting a low level of the second pulse modulation signal; wherein, The first end of the first capacitor is connected to the second end of the second switch tube, and the second end of the first capacitor is grounded; The first end of the fourth switch tube is connected to the first end of the first capacitor, the second end of the fourth switch tube is connected to the first end of the first inductor, and the third end of the fourth switch tube is connected to the first output pin of the control unit; A first end of the fifth switch tube is connected to a first end of the first inductor, a second end of the fifth switch tube is grounded, and a third end of the fifth switch tube is connected to a second output pin of the control unit; The first end of the sixth switch tube is connected to the second end of the first inductor, the second end of the sixth switch tube is connected to the positive electrode of the backup battery, and the third end of the sixth switch tube is connected to the third output pin of the control unit; The first end of the seventh switch tube is connected to the first end of the sixth switch tube, the second end of the seventh switch tube is grounded, and the third end of the seventh switch tube is connected to the fourth output pin of the control unit; A first end of the second capacitor is connected to the positive electrode of the backup battery, and a second end of the second capacitor is grounded.

10. The backup power supply circuit according to claim 8, characterized in that: The boost circuit includes a third capacitor, an eighth switch tube, a ninth switch tube, a second inductor and a fourth capacitor; the control unit includes a first output pin for outputting a high level of a first pulse modulation signal and a second output pin for outputting a low level of the first pulse modulation signal; wherein, The first end of the third capacitor is connected to the second end of the second switch tube, and the second end of the third capacitor is grounded; The first end of the eighth switch tube is connected to the first end of the third capacitor, the second end of the eighth switch tube is connected to the first end of the second inductor, and the third end of the eighth switch tube is connected to the first output pin of the control unit; The first end of the ninth switch tube is connected to the second end of the eighth switch tube, the second end of the ninth switch tube is grounded, and the third end of the ninth switch tube is connected to the second output pin of the control unit; The second end of the second inductor is connected to the positive electrode of the backup battery; A first end of the fourth capacitor is connected to the positive electrode of the backup battery, and a second end of the fourth capacitor is grounded.

11. The backup power supply circuit according to claim 8, characterized in that: The step-down circuit includes a fifth capacitor, a third inductor, a tenth switch tube, an eleventh switch tube and a sixth capacitor; the control unit includes a third output pin for outputting a high level of the second pulse modulation signal and a fourth output pin for outputting a low level of the second pulse modulation signal; wherein, The first end of the fifth capacitor is connected to the second end of the second switch tube, and the second end of the fifth capacitor is grounded; The first end of the third inductor is connected to the first end of the fifth capacitor, the second end of the third inductor is connected to the first end of the tenth switch tube, the second end of the tenth switch tube is connected to the positive electrode of the backup battery, and the third end of the tenth switch tube is connected to the third output pin of the control unit; The first end of the eleventh switch tube is connected to the first end of the tenth switch tube, the second end of the eleventh switch tube is grounded, and the third end of the eleventh switch tube is connected to the fourth output pin of the control unit; A first end of the sixth capacitor is connected to the positive electrode of the backup battery, and a second end of the sixth capacitor is grounded.

12. A method for controlling a backup power supply circuit, characterized in that: Based on the backup power supply circuit according to any one of claims 1 to 11 above, the method comprises: Detecting a connection status of the first interface and a connection status of the at least one second interface; The operation states of the input-output circuit and the DC conversion circuit are controlled according to the connection state of the first interface and the connection state of the at least one second interface.

13. The method according to claim 12, characterized in that The controlling the operation state of the input-output circuit and the DC conversion circuit according to the connection state of the first interface and the connection state of the at least one second interface includes: If the first interface is not connected to the input power supply and all the second interfaces are not connected to the load, the input-output circuit and the DC conversion circuit are controlled to be turned off; If the first interface is not connected to an input power source and at least one of the second interfaces is connected to a load, the DC conversion circuit is controlled to be turned on, and the part of the input-output loop connected between the DC conversion circuit and the second interface is controlled to be turned on, so that the backup battery supplies power to the load connected to the at least one second interface; If the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source first supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged; If the first interface is connected to an input power source and all the second interfaces are not connected to a load, the DC conversion circuit is controlled to be turned on, and the input-output loop is controlled to be partially turned on between the first interface and the DC conversion circuit, so that the input power source charges the backup battery.

14. The method according to claim 13, characterized in that The method further comprises: Real-time detection of the current output by the at least one second interface to the load and the charging current of the backup battery; Correspondingly, if the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, the input-output circuit is controlled to be turned on, and the DC conversion circuit is controlled to be turned on or off, so that the input power source preferentially supplies power to the load connected to the at least one second interface, and charges the backup battery when there is excess power, and the backup battery is powered off after being fully charged, including: If the first interface is connected to an input power source and at least one of the second interfaces is connected to a load, controlling the input-output loop to be partially conductive between the first interface and the second interface; Determine the charging current for the backup battery according to the current output to the load by the second interface connected to the load and the maximum operating current of the input power supply detected in real time; Controlling the partial conduction of the input-output loop between the first interface and the DC conversion circuit, and controlling the DC conversion circuit to be turned on, so that the input power source charges the backup battery with the charging current; According to the charging current of the backup battery detected in real time, it is determined whether the backup battery is fully charged, and when the backup battery is fully charged, the DC conversion circuit is controlled to be turned off, so that the backup battery is powered off.

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