CN110445248B - Main and standby power supply switching circuit and method - Google Patents

The invention relates to a main and standby power supply switching circuit and a method, belongs to the technical field of main and standby power supply switching, and solves the problems that seamless connection cannot be guaranteed and PCB area and chip pins are sacrificed due to the use of external capacitors in the conventional switching circuit. The standby power supply passage is provided with the adjustable buck-boost voltage stabilizer and the standby power supply anti-reverse current circuit which are sequentially arranged in the standby power supply circuit; the main power supply path voltage stabilizer and the main power supply anti-reflux circuit are sequentially arranged in the main power supply loop; the CPU control switching unit is used for adjusting the voltage level of the adjustable buck-boost voltage stabilizer of the standby power supply path when the standby power supply is needed to supply power until the voltage level after the standby power supply anti-reverse current circuit is higher than the voltage level of the voltage stabilizer of the main power supply path after the main power supply discharge reverse current circuit, and switching the standby power supply to supply power; and the standby power supply is switched to the main power supply when the main power supply is needed.

Main and standby power supply switching circuit and method

Technical Field

The invention relates to the technical field of main and standby power switching, in particular to a main and standby power switching circuit and a method.

Background

The existing external load, especially the SoC chip system, has higher and higher requirements on the stability and the continuity of a power supply system; for a digital module with data loss caused by power failure, the stability and the continuity of power supply are ensured; therefore, the power supply is generally required to be two-way or even more than two-way. In general, one path is a main power source and the other path is a standby power source. When the chip works normally, the main power supply supplies power to the system, and when the chip enters a sleep mode, the system automatically switches to a standby power supply to supply power so as to achieve the purpose of storing data.

In the existing standby power supply switching circuit, if a power supply circuit without an external energy storage element is adopted, severe jump of output voltage is easily caused; although the output voltage can be prevented from jumping to some extent by using an external energy storage element power supply circuit (such as adding an external capacitor), this approach will sacrifice the external PCB area and the number of pins of the chip, and is not suitable for the chip-level load.

Therefore, it is desirable to provide a circuit capable of switching between a main power supply and a standby power supply, which can prevent abrupt jump of output voltage, ensure seamless connection, and supply sufficient and uninterrupted power, and does not need to sacrifice external PCB area and the number of pins of a chip.

Disclosure of Invention

In view of the foregoing analysis, the present invention is directed to a main/standby power switching circuit, so as to solve the problems of the conventional main/standby switching circuit, such as severe output voltage jump, no guarantee of seamless connection, and no guarantee of sufficient and uninterrupted power supply, and the problem of sacrificing external PCB area and the number of pins of a chip due to the use of an external capacitor in the standby circuit.

The purpose of the invention is mainly realized by the following technical scheme:

a main/standby power switching circuit includes: the standby power supply passage adjustable buck-boost voltage stabilizer, the main power supply passage voltage stabilizer, the main power supply anti-reverse flow circuit, the standby power supply anti-reverse flow circuit and the CPU control switching unit; wherein,

the standby power supply passage adjustable buck-boost voltage stabilizer and the standby power supply anti-reverse current circuit are sequentially arranged in a standby power supply loop; the main power supply access voltage stabilizer and the main power supply anti-reflux circuit are sequentially arranged in a main power supply loop;

the CPU control switching unit is used for adjusting the voltage level of the adjustable buck-boost voltage stabilizer of the standby power supply path when the standby power supply is needed to supply power until the voltage level after the standby power supply anti-reverse current circuit is higher than the voltage level of the main power supply path voltage stabilizer after the main power supply discharge reverse current circuit, and switching the standby power supply to supply power; and the standby power supply is switched to the main power supply when the main power supply is needed.

On the basis of the scheme, the invention is further improved as follows:

further, after the CPU controls the switching unit to adjust the voltage level of the adjustable buck-boost regulator of the standby power supply path, the standby power supply anti-backflow circuit is started;

after the standby power supply supplies power, the main power supply path voltage stabilizer is closed when the standby power supply supplies power with stable voltage, and the voltage level of the voltage-boosting voltage stabilizer can be adjusted by adjusting the standby power supply path until the voltage level after the standby power supply anti-reverse current circuit is lower than the voltage level of the main power supply path voltage stabilizer after the main power supply discharge reverse current circuit.

Further, when the standby power supply is switched to the main power supply, the main power supply passage voltage stabilizer is started, and after the main power supply voltage is stabilized, the standby power supply passage adjustable buck-boost voltage stabilizer and the standby power supply anti-backflow circuit are closed.

Further, the adjustable buck-boost regulator of stand-by power supply path includes: the wide voltage domain linear voltage stabilizing circuit, the level conversion circuit and the voltage regulating circuit; wherein,

the output end of the CPU control switching unit is connected with the input end of the level switching circuit, the output end of the level switching circuit is connected with the input end of the voltage regulating circuit, and the output end of the voltage regulating circuit is connected with the input end of the wide voltage domain linear voltage stabilizing circuit;

the voltage regulating circuit is used for regulating the voltage division ratio according to the control signal output by the CPU control switching unit so as to regulate the current at the output end of the voltage regulating circuit;

the wide voltage domain linear voltage stabilizing circuit changes the voltage of the output end based on the current input by the input end;

and the output end of the wide voltage domain linear voltage stabilizing circuit is connected with the input end of the standby power supply anti-reverse current circuit.

Further, the wide voltage domain linear voltage stabilizing circuit comprises: the band-gap reference circuit, the operational amplifier, the first switch MOS tube and the resistor R1; wherein,

the output end of the standby power supply is respectively connected with the positive electrode of the power end of the band-gap reference circuit and the source electrode of the first switch MOS tube;

the output end of the band-gap reference circuit is connected with the inverting input end of the operational amplifier;

the non-inverting input end of the operational amplifier is connected with one end of the resistor R1, the other end of the resistor R1 is connected with the drain electrode of the first switch MOS tube, and the output end of the operational amplifier is connected with the grid electrode of the first switch MOS tube;

the drain electrode of the first switch MOS tube is the output end of the wide voltage domain linear voltage stabilizing circuit;

the non-inverting input end of the operational amplifier is the input end of the wide voltage domain linear voltage stabilizing circuit.

Further, the voltage regulating circuit comprises a second switch MOS tube, a resistor R2 and a resistor R3;

the grid electrode of the second switch MOS tube is connected with the output end of the level conversion circuit, and the drain electrode of the second switch MOS tube is connected with the input end of the wide voltage domain linear voltage stabilizing circuit; the source electrode of the second switch MOS tube is grounded through a resistor R3;

and two ends of the resistor R2 are respectively connected with the source electrode and the drain electrode of the second switch MOS tube.

Furthermore, the circuit also comprises a standby power supply electric quantity self-detection module which is used for detecting the voltage of the standby power supply and sending the detection result to the CPU control switching unit; and when the voltage of the standby power supply is lower than the voltage threshold value, stopping using the standby power supply for supplying power.

Further, the backup power supply anti-reverse current circuit includes: a third switch MOS tube, a fourth switch MOS tube and a fifth switch MOS tube; wherein,

the source electrode of the third switch MOS tube and the grid electrode of the fourth switch MOS tube are both connected with the main power supply voltage; the grid electrode of the third switch MOS tube and the source electrode of the fourth switch MOS tube are both connected with the voltage of the standby power supply battery; the third switch MOS tube is connected with the drain electrode and the substrate of the fourth switch MOS tube and then connected with the substrate of the fifth switch MOS tube; the drain electrode of the fifth switch MOS tube is connected with the output end of the wide voltage domain linear voltage stabilizing circuit; the grid electrode of the fifth switching MOS tube is used for receiving a switching signal of the CPU control switching unit; and taking the source electrode of the fifth switching MOS tube as the output end of the standby power supply anti-reverse-current circuit for connecting a load.

Further, the voltage level after the backup power supply anti-reverse current circuit is higher than the voltage level after the main power supply path voltage stabilizer passes through the main power supply discharge reverse current circuit, including:

the voltage is higher than the output voltage of the main power supply channel voltage stabilizer by 10-15 percent;

the voltage quasi-position behind the anti-reverse current circuit of stand-by power is less than the voltage quasi-position behind main power source discharge reverse current circuit of main power source access stabiliser, includes:

is lower than 10-15% of the output voltage of the main power supply channel voltage stabilizer.

The invention also provides a main/standby power switching method, which is realized based on the main/standby power switching circuit and executes the following operations in the CPU control switching unit:

receiving and analyzing a control instruction and detecting the current power supply state; wherein the control instruction is to supply power by using a main power supply or a standby power supply;

when the control instruction is that a main power supply is used for supplying power and the standby power supply is not used for supplying power at the current moment, controlling the main power supply to supply power;

when the control instruction is that a standby power supply is used for supplying power and a main power supply is supplying power at the current moment, starting the adjustable buck-boost voltage stabilizer of the standby power supply path, adjusting the voltage level of the adjustable buck-boost voltage stabilizer of the standby power supply path until the voltage level after passing through the anti-reverse-current circuit of the standby power supply is higher than the voltage level after passing through the main power supply discharge reverse-current circuit of the main power supply path stabilizer, starting the anti-reverse-current circuit of the standby power supply, and switching the power supply of the standby power supply; when the supply voltage of the standby power supply is stable, the main power supply path voltage stabilizer is closed, the voltage level of the voltage-boosting voltage stabilizer can be adjusted by adjusting the standby power supply path until the voltage level after passing through the standby power supply anti-reverse-current circuit is lower than the voltage level of the main power supply path voltage stabilizer after passing through the main power supply discharge reverse-current circuit;

when the control instruction is that the main power supply is utilized to supply power and the standby power supply is supplying power at the current moment, the main power supply passage voltage stabilizer is started, the standby power supply passage adjustable buck-boost voltage stabilizer is closed after the main power supply supplies power and the main power supply passage supply voltage is stable, and the standby power supply discharge reverse current circuit is closed.

The invention has the following beneficial effects:

according to the master and standby power switching circuit and method, the buck-boost pretreatment of the output voltage of the adjustable buck-boost voltage stabilizer of the standby power path is realized through control feedback, so that the power supply voltage has no voltage mutation and can meet the requirement of seamless power supply, off-chip linear energy storage elements are saved, and the external PCB area and the number of pins of a chip are not sacrificed; meanwhile, the wide-voltage-domain linear voltage stabilizing circuit in the adjustable buck-boost voltage stabilizer meets the requirements of a standby power supply circuit on large power supply voltage and large variation amplitude of the power supply voltage; in addition, the anti-reverse current circuit of the standby power supply circuit adopts a substrate switch design, and the switch can work effectively no matter whether the standby power supply circuit supplies power or not.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

Fig. 1 is a schematic structural diagram of a main/standby power switching circuit in embodiment 1 of the present invention;

fig. 2 is a schematic circuit diagram of an adjustable buck-boost regulator of a standby power path in embodiment 1 of the present invention;

fig. 3 is a schematic structural diagram of a backup power supply anti-backflow circuit in embodiment 1 of the present invention;

fig. 4 is a voltage waveform diagram of the output of the standby power switching circuit in the invention, which is respectively adopted without an external energy storage element, with an external energy storage element and.

Reference numerals:

1-a standby power supply electric quantity self-detection module; 2-main power supply; 3-a standby power supply; 4-main power path regulator; 5, adjusting a buck-boost voltage stabilizer by a standby power supply path; 6-main power supply anti-reverse current circuit; 7-backup power supply anti-reverse current circuit; 8-CPU controls the switching unit; 9-wide voltage domain linear voltage stabilizing circuit; 10-a level shifter circuit; 11-a voltage regulation circuit; 12-substrate switch.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

Example 1

A specific embodiment of the present invention discloses a main/standby power switching circuit, and a schematic structural diagram is shown in fig. 1. The circuit includes: the standby power supply path adjustable buck-boost voltage stabilizer (5), the main power supply path voltage stabilizer (4), the main power supply anti-reverse flow circuit (6), the standby power supply anti-reverse flow circuit (7) and the CPU control switching unit (8); the standby power supply passage adjustable buck-boost voltage stabilizer and the standby power supply anti-reverse current circuit are sequentially arranged in a standby power supply loop; the main power supply access voltage stabilizer and the main power supply anti-reflux circuit are sequentially arranged in a main power supply loop; the CPU control switching unit is used for adjusting the voltage level of the adjustable buck-boost voltage stabilizer of the standby power supply path when the standby power supply is needed to supply power until the voltage level after the standby power supply anti-reverse current circuit is higher than the voltage level after the main power supply path voltage stabilizer passes through the main power supply discharge reverse current circuit, and switching the standby power supply to supply power (3); and is also used for switching the power supply from the standby power supply to the main power supply (2) when the main power supply is needed.

In implementation, when the standby power supply is needed to supply power, the CPU controls the switching unit to send out a boost control signal, and adjusts the standby power supply path to adjust the voltage level of the boost-buck voltage stabilizer until the voltage level after passing through the standby power supply anti-reverse current circuit is higher than the voltage level of the main power supply path voltage stabilizer after passing through the main power supply discharge reverse current circuit, preferably higher than 10% -15% of the output voltage of the main power supply path voltage stabilizer; and meanwhile, the CPU controls the switching unit to send a starting signal to the standby power supply anti-backflow circuit for starting the standby power supply anti-backflow circuit. Since the standby power supply path output voltage is higher than the main power supply path output voltage at this time, the standby power supply (3) is automatically switched to supply power at this time; after the power supply voltage of the standby power supply is stabilized, the main power supply path voltage stabilizer is closed, a voltage reduction control signal is sent out, and the voltage level of the voltage reduction voltage stabilizer can be adjusted by adjusting the standby power supply path until the voltage level after the standby power supply anti-backflow circuit is lower than the voltage level of the main power supply path voltage stabilizer after the main power supply anti-backflow circuit passes through the main power supply discharge anti-backflow circuit, preferably lower than 10% -15% of the output voltage of the main power supply path voltage stabilizer; when the main power supply is needed, the main power supply path voltage stabilizer is enabled, and because the output voltage of the main power supply path is higher than the output voltage of the standby power supply path, the standby power supply is automatically switched to the main power supply; after the power supply voltage of the main power supply is stabilized, the standby power supply passage is closed to adjust the buck-boost voltage stabilizer, and meanwhile, the switch of the standby power supply anti-reverse-current circuit is closed; when the power supply is switched to the standby power supply again, the standby power supply path is required to be firstly started, the adjustable buck-boost voltage regulator is required to be started, and then the voltage regulation operation is carried out.

In the main power switching circuit provided by this embodiment, the step-up and step-down preprocessing is performed on the power supply voltage, so that the requirement of seamless power supply can be met without voltage mutation on the power supply voltage, and meanwhile, the off-chip linear energy storage element is saved without sacrificing the external PCB area and the number of pins of the chip.

Generally, a load (such as a chip and a peripheral load circuit thereof) needs to be powered by a main power supply when working normally; when the electronic device enters the sleep mode, part of functions are disabled, and at the moment, the standby power supply can be used for supplying power, so that the power supply requirements (such as operations of data storage and the like) of the existing functional parts can be met. In particular, the question of when to select the main power supply and when to select the backup power supply is not within the contemplation of the inventive solution. Generally, when the load is a chip and its peripheral load circuit, the CPU control switching unit may be directly disposed in the chip, and it is not necessary to separately provide a corresponding hardware structure for the CPU control switching unit, so as to save the PCB area.

Preferably, the circuit further comprises a standby power supply electric quantity self-detection module (1) for monitoring whether the output voltage of the standby power supply meets the power supply requirement, if so, the CPU control switching unit enables the standby power supply channel and sends the detection result to the CPU control switching unit; and when the output voltage of the standby power supply is lower than the voltage threshold value, stopping using the standby power supply for supplying power.

Preferably, this embodiment further provides a circuit structure of an adjustable buck-boost regulator with a standby power path, including: the circuit comprises a wide voltage domain linear voltage stabilizing circuit (9), a level conversion circuit (10) and a voltage regulating circuit (11); the output end of the CPU control switching unit is connected with the input end of the level conversion circuit, the output end of the level conversion circuit is connected with the input end of the voltage regulating circuit, and the output end of the voltage regulating circuit is connected with the input end of the wide voltage domain linear voltage stabilizing circuit; the voltage regulating circuit is used for regulating the voltage division ratio according to the control signal output by the CPU control switching unit so as to regulate the current at the output end of the voltage regulating circuit; the wide voltage domain linear voltage stabilizing circuit changes the voltage of the output end based on the current input by the input end; and the output end of the wide voltage domain linear voltage stabilizing circuit is connected with the input end of the standby power supply anti-reverse current circuit. Wherein, wide voltage domain linear voltage regulator circuit includes: the band-gap reference circuit, the operational amplifier, the first switch MOS tube and the resistor R1; the output end of the standby power supply is respectively connected with the positive electrode of the power end of the band-gap reference circuit and the source electrode of the first switch MOS tube and used for supplying power to the band-gap reference circuit and the source electrode of the first switch MOS tube. The output end of the band-gap reference circuit is connected with the inverting input end of the operational amplifier; the non-inverting input end of the operational amplifier is connected with one end of the resistor R1, the other end of the resistor R1 is connected with the drain electrode of the first switch MOS tube, and the output end of the operational amplifier is connected with the grid electrode of the first switch MOS tube; the drain electrode of the first switch MOS tube is the output end of the wide voltage domain linear voltage stabilizing circuit; the non-inverting input end of the operational amplifier is the input end of the wide voltage domain linear voltage stabilizing circuit. The voltage regulating circuit comprises a second switching MOS tube, a resistor R2 and a resistor R3; the grid electrode of the second switch MOS tube is connected with the output end of the level conversion circuit, and the drain electrode of the second switch MOS tube is connected with the input end of the wide voltage domain linear voltage stabilizing circuit; the source electrode of the second switch MOS tube is grounded through a resistor R3; and two ends of the resistor R2 are respectively connected with the source electrode and the drain electrode of the second switch MOS tube.

When the CPU sends the voltage rising and reducing signals to control the adjustable voltage rising and reducing voltage stabilizer of the standby power supply passage, the voltage rising and reducing signals are digital signals, and the voltage of the digital signals is too low to directly control the analog circuit of the high-voltage element. Therefore, a level conversion circuit is provided, by which a digital low voltage is converted into an analog high voltage. The Level conversion circuit can be realized by adopting a common Level-Shifter, and the converted analog signal can control the voltage regulating circuit. The voltage regulating circuit is realized by connecting a switch MOS and a resistor string in parallel, and the resistance value of the resistor string is changed by controlling the short circuit and the conduction of the resistor string. Because the resistance value of the resistor string is changed, the voltage division ratio is changed, the current at the input end of the wide voltage domain linear voltage stabilizing circuit is changed, and because the reference voltage given by the gap reference in the wide voltage domain linear voltage stabilizing circuit is not changed, the voltage fed back to the connection point of the resistor string is not changed by utilizing the principle of virtual short circuit at the two input ends of the two-stage operational amplifier and the negative feedback principle. And the proportion of voltage division of the resistor string is changed, the current flowing through the resistor R1 is changed, and then the voltage division on the R1 is changed, so that the voltage of the output end is changed finally, and the voltage increasing and decreasing operation is realized. The step-up and step-down ratio can be realized by changing the resistance in the voltage regulating circuit. Preferably, the operational amplifier can be a two-stage operational amplifier, the number of cascaded MOS of the amplifier is small, the required total overdrive voltage is low, and the operation in a saturation region can be satisfied even if the power supply voltage is low, so that a wide voltage domain is realized. A schematic diagram of a circuit structure of the adjustable buck-boost regulator with the standby power path is shown in fig. 2.

Preferably, the present embodiment further provides a schematic diagram of a backup power supply anti-backflow circuit structure, as shown in fig. 3. The circuit includes: a third switch MOS tube, a fourth switch MOS tube and a fifth switch MOS tube; and a substrate switch (12) is formed by combining the third switch MOS tube and the fourth switch MOS tube. The source electrode of the third switch MOS tube and the grid electrode of the fourth switch MOS tube are both connected with the main power supply voltage; the grid electrode of the third switch MOS tube and the source electrode of the fourth switch MOS tube are both connected with the voltage of the standby power supply battery; the third switch MOS tube is connected with the drain electrode and the substrate of the fourth switch MOS tube and then connected with the substrate of the fifth switch MOS tube; the drain electrode of the fifth switch MOS tube is connected with the output end of the wide voltage domain linear voltage stabilizing circuit; the grid electrode of the fifth switching MOS tube is used for receiving a switching signal of the CPU control switching unit; and taking the source electrode of the fifth switching MOS tube as the output end of the standby power supply anti-reverse-current circuit for connecting a load. Because the voltage of the battery is lower than the power supply voltage, if a common diode anti-reverse current switch of a power supply circuit is adopted, the final output voltage level is too low due to the fact that the diode has overlarge cross voltage (700mV), and power cannot be supplied to a load chip, a special switch structure is adopted, the substrate switch of the structure is used for enabling a high level in the battery or the power to be always connected to a Body (substrate) end of the switch MOS, so that the switch MOS can normally work due to the fact that the Body end is at the highest potential regardless of battery power supply or power supply, and the cross voltage of the switch MOS is very low (less than 200mV), so that the power supply requirement of the battery circuit is met, the reverse current of an output end can be blocked, and the cross voltage requirement of a standby power supply which is a low-voltage battery can also be guaranteed.

Fig. 4 is a voltage waveform diagram of output when the switching standby power supply without the external energy storage element, with the external energy storage element and adopting the buck-boost modulation of the invention without the energy storage element is adopted from top to bottom. It can be seen that when there is no external energy storage element, since the output voltage levels of the initial main and standby circuits are equal, even if the standby circuit voltage stabilizer is enabled in advance, power cannot be supplied, so that the standby voltage stabilizer can start to supply power when switching, the output voltage has severe jump, the output voltage is pulled to be very low, and if power is supplied at this time, an error is brought to the output of a subsequent circuit; when the external energy storage element with a large capacitance value is provided, the jump of the output voltage is effectively prevented by using the voltage mutation-free characteristic of the external capacitor, but the external PCB area and the pin number of the chip are sacrificed at the moment; when the main/standby power supply switching circuit in this embodiment is applied, the standby circuit is boosted in advance during switching, so that the standby power supply supplies power in advance, and further, the output voltage is prevented from jumping, and the purpose of seamless voltage transition is achieved.

Example 2

In embodiment 2 of the present invention, a method for switching a main/standby power supply is also disclosed, which is implemented based on the main/standby power supply switching circuit, and executes the following operations inside a CPU control switching unit:

step S1: receiving and analyzing a control instruction and detecting the current power supply state; wherein the control instruction is to supply power by using a main power supply or supply power by using a standby power supply. The control instruction is supplied with power by a main power supply or by a standby power supply, and the time and the type of the control instruction can be designed by a user according to needs. For example, when the system works normally, the control instruction is sent to supply power by using a main power supply; when entering the sleep mode, the control instruction is sent to supply power by using the standby power supply.

Step S2:

step S21: when the control instruction is that a main power supply is used for supplying power and the standby power supply is not used for supplying power at the current moment, controlling the main power supply to supply power;

step S22: when the control instruction is that a standby power supply is used for supplying power and a main power supply is supplying power at the current moment, starting the adjustable buck-boost voltage stabilizer of the standby power supply path, adjusting the voltage level of the adjustable buck-boost voltage stabilizer of the standby power supply path until the voltage level after passing through the anti-reverse-current circuit of the standby power supply is higher than the voltage level after passing through the main power supply discharge reverse-current circuit of the main power supply path stabilizer, starting the anti-reverse-current circuit of the standby power supply, and switching the power supply of the standby power supply; when the supply voltage of the standby power supply is stable, the main power supply path voltage stabilizer is closed, the voltage level of the adjustable voltage-boosting and voltage-reducing voltage stabilizer of the standby power supply path is adjusted to be lower than the voltage level of the main power supply path voltage stabilizer, and the voltage level is lower than the voltage level of the main power supply path voltage stabilizer after passing through the main power supply discharge reverse-flow circuit after passing through the standby power supply reverse-flow prevention circuit;

step S23: when the control instruction is that the main power supply is utilized to supply power and the standby power supply is supplying power at the current moment, the main power supply passage voltage stabilizer is started, the standby power supply passage adjustable buck-boost voltage stabilizer is closed after the main power supply supplies power and the main power supply passage supply voltage is stable, and the standby power supply discharge reverse current circuit is closed.

The specific implementation process of the method embodiment of the present invention may refer to the above circuit embodiment, and this embodiment is not described herein again. Since the principle of the embodiment of the method is the same as that of the circuit embodiment, the method also has the corresponding technical effect of the circuit embodiment.

Those skilled in the art will appreciate that all or part of the flow of the method implementing the above embodiments may be implemented by a computer program, which is stored in a computer readable storage medium, to instruct related hardware. The computer readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.