WO2009059516A1

WO2009059516A1 - Device and method for controlling switch of main power supply and backup power supply

Info

Publication number: WO2009059516A1
Application number: PCT/CN2008/072788
Authority: WO
Inventors: Huafu Li; Jigao Chen
Original assignee: Chengdu Huawei Symantec Technologies Co., Ltd.
Priority date: 2007-10-29
Filing date: 2008-10-22
Publication date: 2009-05-14
Also published as: CN101202468A; CN100563080C

Abstract

A device and method for controlling the switch of a main power supply and a backup power supply. The device includes a main circuit power switch module (110), an over-voltage and under-voltage detection module (120), a backup circuit slow-start module (140) and a backup circuit control module (130). When the voltage of the main power supply is normal, the main power supply is provided to a load. When an over-voltage or an under-voltage occurs, the backup power supply is provided to the load.

Description

Method and device for switching between main and standby power sources

Technical field

The present invention relates to power supply technologies, and in particular, to a method and apparatus for active/standby power switching control. Background technique

In the design of electronic equipment or electronic circuits, in order to improve the reliability of equipment or system operation, it is often necessary to set backup power supply corresponding to the main power supply; in the implementation scheme of setting backup power supply, the main power supply switching control is the most critical technical link. One.

Referring to FIG. 1 , it is a schematic structural diagram of a master/slave power switching control device in the prior art. The device comprises a main circuit power switch module, an undervoltage detection module, a backup path restart module and a backup path control module.

The undervoltage detection module is configured to perform undervoltage detection on a main power supply voltage input to the device, and output an indication signal that is higher than an undervoltage when the voltage is higher than the undervoltage point; and output an undervoltage when the voltage is lower than the voltage point The indication signal of the pressure. The undervoltage detection module is implemented by a high cost dedicated chip.

The main circuit power switch module provides a main power supply to the load when receiving an indication signal higher than the undervoltage transmitted by the undervoltage detection module; receiving an indication of the undervoltage transmitted by the overvoltage and undervoltage detection module When the signal is signaled, the main power supplied to the load is cut off. The main circuit power switch module is implemented by a diode.

The standby path slowing module is configured to slowly transfer the backup power to the backup path control module when the device is connected to the system. The standby slow-start module is implemented using separate components and a high-cost dedicated chip. The system is a motherboard that completes powering the load.

The standby path control module, when receiving the indication signal higher than the undervoltage transmitted by the undervoltage detection module, cuts off the backup power supply provided by the backup path buffer module provided to the load; When the voltage detection module transmits the undervoltage indication signal, the backup power transmitted by the backup buffer module is provided to the load. At present, in the circuit implementation of the apparatus for the active/standby power switching control shown in FIG. 1, the circuit shown in FIG. 2 is generally employed. The main power switch module in Figure 1 is realized by the diode D1 in Figure 2. The main power supply and the backup power supply are energized by the diode D1, and the main power input is higher than the replacement page (detail) In the case of an undervoltage point, the main power supply for the load is supplied through the diode D1. The standby buffer module in Figure 1 is implemented by the MOS switch Q1, the hot-swap chip LT1422 U2, R7, Rl, C2 and CI in Fig. 2, through hot-swappable chips LT1422 U2, R7, Rl, C2 and CI, The control MOS switch Q1 is slowly turned on, and the backup power of the input MOS switch Q1 is transmitted to the PMOS transistor Q2. The undervoltage detection module in Figure 1 is implemented by the voltage monitoring chips MC33161 U2, R5 and R6 in Figure 2 for undervoltage detection of the main supply voltage. When the main supply voltage is lower than the undervoltage point, the voltage monitoring chip MC33161 U2 The output low voltage controls the PMOS transistor Q2 to conduct, and supplies the backup power to the load. The standby control module in Figure 1 is implemented by Q2, R2, R3, and D2 in Figure 2. The existing scheme of active/standby power switching control has the following disadvantages:

In the prior art, the undervoltage detection is performed on the main power supply through the undervoltage detection module, so that the main power supply can be switched from the main power supply to the backup power supply when the main power supply is lower than the undervoltage point, but there is no corresponding protection measure when the main power supply voltage is too high. This causes damage to the device and power supply load of the active/standby power switching control. Therefore, the switching control of the active and standby power supplies is not perfect, and the power supply to the load cannot be ensured safely.

It can be seen that the existing active/standby power switching control scheme has the disadvantage of being imperfect.

Summary of the invention

The embodiment of the invention provides a device for switching between the active and standby power sources, which can improve the switching control of the active and standby power sources.

The embodiment of the invention provides a method for switching between the active and standby power sources, which can improve the switching control of the active and standby power sources.

The invention adopts the following technical solutions:

A device for switching control of an active/standby power supply, the device comprising a main circuit power switch module, an over/under voltage detection module, a backup path slow start module and a backup path control module;

The over-undervoltage detection module is configured to perform over-voltage detection on the main power supply voltage input to the device, and detect an indication signal that the output voltage is normal when the voltage is normal; and an indication that the output voltage is abnormal when the voltage over-voltage or under-voltage is detected Signal

The main circuit power switch module receives the normal voltage transmitted by the overvoltage and undervoltage detection module Receiving a main power supply to the load when receiving the indication signal; and cutting off the main power supply provided to the load when receiving the indication signal of the abnormal voltage transmitted by the over-undervoltage detection module;

The standby path control module provides backup power to the load when receiving the indication signal of the abnormal voltage transmitted by the overvoltage and undervoltage detection module; and receiving the indication signal of the normal voltage transmitted by the overvoltage and undervoltage detection module , cut off the backup power supplied to the load.

Another technical solution used in the present invention is as follows:

A method for switching power between active and standby power sources, the method comprising:

The undervoltage detection is performed on the main power supply voltage, and an indication signal indicating that the output voltage is normal when the voltage is normal is detected, and the main power switch is controlled to supply the main power to the load;

An indication signal indicating that the output voltage is abnormal when the main power supply voltage is overvoltage or undervoltage is detected, and the backup standby power switch supplies the backup power to the load.

As can be seen from the above solution, the embodiment of the present invention not only performs undervoltage detection on the main power supply, but also performs overvoltage detection on the main power supply. When the main power supply is lower than the undervoltage point or higher than the overvoltage point, the main power source is switched to the main power source. Backup power. Thereby, the switching control of the active and standby power sources is further improved, and the load is normally powered more efficiently.

DRAWINGS

1 is a schematic structural diagram of an apparatus for switching between main and standby power sources in the prior art;

2 is a schematic circuit diagram of an apparatus for switching between main and standby power sources in the prior art;

3 is a schematic structural diagram of an apparatus for switching power supply between a main and a backup power supply according to an embodiment of the present invention;

4 is a schematic circuit diagram of an apparatus for switching between main and standby power supplies according to an embodiment of the present invention;

Figure 5 is a circuit diagram of the over-voltage detecting module 120 and the main-path power switch module 110 of Figure 4;

6 is a circuit diagram of the hysteresis control module 150 of FIG. 4;

7 is a circuit diagram of the standby path slow-start module 140 of FIG. 4;

8 is a circuit diagram of the backup path control module 130 of FIG. 4;

FIG. 9 is a circuit diagram of the main road abnormality display module 160 of FIG. detailed description

In order to make the objects, the technical solutions and the advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the embodiments and drawings.

3 is a schematic structural diagram of an apparatus for switching power supply between a main and a backup power supply according to an embodiment of the present invention. The apparatus includes a main power switch module 110, an over/under voltage detection module 120, a backup path refresh module 140, and a backup path control module 130.

The over-voltage detecting module 120 is configured to perform over-voltage detection on the main power supply voltage input to the device, and detect an output signal with a normal output voltage when the voltage is normal; and an indication signal that the output voltage is abnormal when a voltage over-voltage or under-voltage is detected. .

The main circuit power switch module 110 provides the main power supply to the load when receiving the indication signal of the normal voltage transmitted by the over-voltage detecting module 120; and receives the indication signal of the abnormal voltage transmitted by the over-voltage detecting module 120, and cuts off The main power supplied to the load.

The main power switch module 110 can be implemented by a diode or by a MOS switch. If the MOS switch is used to supply power to the load when the MOS switch is turned on, the internal resistance is small when the MOS switch is turned on, and the voltage loss is small, which can reduce power consumption.

The standby circuit control module 130, when receiving the indication signal of the voltage abnormality transmitted by the overvoltage detection module 120, provides the backup power transmitted by the backup buffer module 140 to the load; and receives the transmission by the overvoltage and undervoltage detection module 120. When the voltage is normal, the backup power supplied by the standby buffer module 140 to the load is cut off.

The backup path control module 130 includes a backup power switch control module 131 and a backup power switch module.

132.

The backup power switch control module 131 is configured to: when receiving the indication signal of the abnormality of the voltage transmitted by the overvoltage detection module 120, the control standby power switch module 132 provides the backup power transmitted by the backup buffer module 140 to the load; Upon receiving the indication signal of the normal voltage transmitted by the overvoltage detecting module 120, the control standby power switching module 132 cuts off the backup power supplied from the standby buffer module 140 to the load. The backup power switch module 132 is configured to provide the backup power transmitted by the backup buffer module 140 to the load under the control of the backup power switch control module 131, or to cut off the backup buffer module 140 provided to the load. The backup power delivered.

The backup path refresh module 140 is configured to slowly transfer the backup power to the backup path control module 130 when the device is connected to the system. The standby slow-start module 140 includes a backup slow-start power switch module 142 and a backup anti-shake and slow-start module 141.

The standby anti-shake and slow-start module 141 is respectively connected to the input end and the output end of the standby-powered power switch module 142. When the device is connected to the system, the backup bypass power switch module 142 is slow to prevent jitter. The backup power is transmitted to the backup power switch module 132, and the backup power switch module 142 is configured to transmit the backup power to the backup power switch module 132 under the control of the standby anti-shake and slow-start module 141.

The standby circuit module 140 can be implemented in the same manner as in the prior art, that is, by using the hot-swappable chip LT1422 U2 or the like; or by separating components, and the specific circuit can be as shown in FIG. 7. Since the cost of the discrete components is much lower than the components of the hot-swappable chip LT1422 U2, this reduces the cost.

Optionally, the apparatus for the active/standby power switching control of the embodiment of the present invention further includes a hysteresis control module 150, configured to send the indication signal of the normal voltage transmitted by the overvoltage and undervoltage detection module 120 to the overvoltage and undervoltage detection module 120. The hysteresis signal; when receiving the indication signal of the voltage abnormality transmitted by the overvoltage detection module 120, the hysteresis signal is not sent to the overvoltage/undervoltage detection module 120.

Correspondingly, the overvoltage and undervoltage detection module 120 reduces the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point according to the received hysteresis signal; or, raises the overvoltage point from the original overvoltage point to Overvoltage detection hysteresis switching point; or, the undervoltage point is reduced from the original undervoltage point to the undervoltage detection hysteresis switching point, and the overvoltage point is raised from the original overvoltage point to the overvoltage detection hysteresis switching point;

When the overvoltage and undervoltage detection module 120 does not receive the hysteresis signal transmitted by the hysteresis control module 150, the undervoltage point is set at the original undervoltage point, and the overvoltage point is set at the original overvoltage point.

Optionally, the apparatus for controlling the active/standby power supply of the embodiment of the present invention includes a circuit abnormal display mode. The block 160 is configured to display a state in which the main circuit is abnormal after receiving the indication signal of the voltage abnormality outputted by the undervoltage detection module 120.

Optionally, the output end of the main circuit power switch module 110 is connected to the output end of the backup power switch module 132, and then connected to the circuit abnormality display module 160 to provide power for the circuit abnormality display module 160; and connected to the hysteresis control module 150. Providing power to the hysteresis control module 150; and connecting to the backup power switch control module 131 to provide power for the backup power switch control module 131.

According to the actual design, the device structure of the active/standby power switching control of the embodiment of the present invention is implemented in various ways. Here, the structure shown in FIG. 3 is specifically illustrated by taking the circuit shown in FIG. 4 as an example. The main circuit power switch module 110 is implemented by using a MOS switch.

Referring to FIG. 4, it is a schematic circuit diagram of an apparatus for switching power supply between a main and a backup power supply according to an embodiment of the present invention, and a specific implementation circuit of each module is marked in the figure.

Referring to FIG. 5, it is a circuit diagram of the overvoltage detecting module 120 and the main power switching module 110 in FIG. The main circuit power switch module is the MOS switch Q1 described in the figure. The overvoltage and undervoltage detection module is implemented by two TL431 (Ul, U2) and peripheral resistors, including R1, R2, R3, R4, R5, R6 and Cl. The TL431 is a voltage comparator with a reference voltage with a reference voltage Vref of 2.5V or 1.25V. Overvoltage detection is performed by Rl, R2, and U1, and undervoltage detection is performed by R3, R4, and U2. The original overvoltage point of the overvoltage detection module is: (1+R1/R2) X Vref; The original undervoltage point of the undervoltage detection module circuit is: (1+R3/R4) Vref.

When the main power input voltage is between {{1+R3/R4) Vref ~ (1+R1/R2) Vref } between the original undervoltage point and the original overvoltage point, the overvoltage and undervoltage detection module outputs Vmoni as a low level voltage, MOS The switch Q1 is turned on, and the main power supply supplies power to the load. At the same time, the over-voltage and under-voltage detection module outputs a low level to the hysteresis control module. At this time, the hysteresis control module circuit and the over-under-voltage detection module circuit realize the undervoltage point. The pressure point (1+R3/R4) Vref is reduced to the undervoltage detection hysteresis switching point [1+(R3//R22)/R4] Vref. Correspondingly, the normal voltage of the overvoltage and undervoltage detection module is {(l+IG/). R ⁴ ) χ Vref ~ (1+R1/R2) Vref } becomes {[1+(R3//R22)/R4] Vref ~ (1+R1/R2) Vref } , where R22 is late Thereafter, when the main power input voltage is abnormal, that is, lower than [1+(R3//R22)/R4] X Vref or higher than (1+R1/R2) Vref, the over-undervoltage detection output Vmoni is a high-level voltage. That is, VOUT is high, MOS switch Q1 is turned off, the main power supply is disconnected from the power supply circuit provided by the load, and the normal voltage range of the overvoltage and undervoltage detection module is returned to { (1+R3/R4) Vref ~ (1+R1) /R2) Vref } , The over-voltage and under-voltage detection module performs over-voltage detection with the normal voltage range after the return. The above process is repeated until the voltage is detected to be normal.

In Figure 5, capacitor C1 is an anti-jitter capacitor to ensure that the output does not change during mains voltage transients.

Referring to FIG. 6, which is a circuit diagram of the hysteresis control module 150 of FIG. 4, the operation process is described in the description of FIG. When the main power supply is abnormal (ie, lower than the undervoltage detection point [l+(R3//R22)/R4] x Vref or higher than the overvoltage detection point (1+Rl/R2) x Vref), the overvoltage and undervoltage detection module outputs Vmoni High voltage

(See Figure 4), MOS transistor Q6 is turned on, diode D2 is turned off, hysteresis control module has no signal output to overvoltage and undervoltage detection circuit module; when main power is normal, overvoltage and undervoltage detection output Vmoni is low voltage

(See Figure 4), MOS transistor Q6 is turned off and diode D2 is turned on. It can be seen that the undervoltage point is determined by the resistor network consisting of R22 in the hysteresis control module and R3 and R4 in the overvoltage and undervoltage detection module.

The hysteresis control module circuit shown in Figure 6 can prevent the main power supply from being damaged due to repeated switching of the main and standby power supplies when the main power supply continuously fluctuates.

Of course, the hysteresis control module can also prevent the main power supply from being damaged due to repeated switching of the main and standby power sources when the main power supply continuously fluctuates; or the hysteresis control module can prevent the main power supply from overvoltage. When the point and undervoltage point fluctuate continuously, the main and standby power supply switching control devices are damaged due to repeated switching of the main and standby power supplies. According to the idea of the hysteresis control module of the present invention, those skilled in the art can implement various corresponding circuit implementations, and details are not described herein again.

Referring to FIG. 7, which is a circuit diagram of the standby path slow-start module 140 in FIG. 4, the standby-side power-switching power module in the standby circuit-opening module is implemented by the MOS switch Q3 in the figure. When the active/standby power switching control device of the embodiment of the present invention is inserted into the system motherboard, since the voltage across the capacitor C2 is not abrupt, the PNP Transistor Q2 is turned on, the charge of capacitor C3 is discharged through Q2 and R9, the gate-source voltage VGS of the power MOS is lower than its threshold voltage Vth, the power MOS switch Q3 is turned off, and the output voltage VSO is zero.

After the system board is inserted normally, the voltage across the capacitor C2 is charged to the backup power supply, and the PNP transistor Q2 is turned off. The backup power supply starts charging the capacitor C3 through R10. When the voltage across C3 is charged to a certain voltage value [Vgh ( th ) When +Vd], the gate of MOS switch Q3 reaches the conduction threshold voltage Vgh ( th ), and MOS switch Q3 starts to conduct. During this time, the voltage of VSO is still 0, and the length of this period is determined by resistor R10 and capacitor C3. Determine together.

After the MOS switch Q3 is turned on, the C3 continues to be charged so that the gate source of the MOS switch Q3 reaches the platform voltage (Vplt), and the feedback capacitor C4, the MOS switch source/drain, and the VSO voltage change at the same voltage change rate; the VSO voltage is The constant voltage change rate is charged from 0 to the voltage of the backup power supply; after the VSO reaches the voltage value of the backup power supply, R10 continues to charge the capacitor C3 and reaches the voltage value of the backup power supply. At this time, the RDS of the MOS switch Q3 is minimum, and the VDS is also reached. The lowest value, the output backup voltage.

The feedback capacitor C4 is sized by the current flowing through it, the inrush current allowed by VSO, and the load capacitance on the VSO. The voltage change rate of the VSO is the ratio of the allowable inrush current of the output network VSO to the load capacitance of the VSO.

Referring to FIG. 8, which is a circuit diagram of the backup path control module 130 in FIG. 4, the backup power switch module in the backup path control module is the PMOS switch Q5 in FIG. When the main power supply is abnormal (ie, lower than the undervoltage detection point [1+(R3//R22)/R4] Vref or higher than the overvoltage detection point (1+R1/R2) Vref), the overvoltage and undervoltage detection module outputs Vmoni as High voltage (see Figure 4), NMOS transistor Q4 is turned on, PMOS switch Q5 is turned on, and the backup power supply supplies power to the load. Conversely, when the main power supply voltage is normal, the over-voltage and under-voltage detection output Vmoni is low voltage (see Figure 4). The standby power switch module PMOS tube Q5 is cut off, and the backup power supply is disconnected from the power supply circuit provided by the load.

Referring to FIG. 9, it is a circuit diagram of the main road abnormality display module 160 in FIG. When the main power supply is abnormal (ie, lower than the undervoltage detection point [1+(R3//R22)/R4] Vref or higher than the overvoltage detection point (1+R1/R2) X Vref), the overvoltage and undervoltage detection module outputs Vmoni. For high voltage (see Figure 4), the NMOS transistor Q7 is turned on, and the LED is lit. By selecting a suitable series current limiting resistor R26, the LED is turned on. The operating current of the LED is in the range of 5 ~ 10mA; on the contrary, when the main power is normal, the over-undervoltage detection module outputs Vmoni as low voltage, the NMOS transistor Q7 is turned off, and the LED is not lit.

Of course, the device for controlling the active/standby power supply switching that can be implemented by the idea of the embodiment of the present invention is not limited to the above-mentioned circuit, and is not enumerated here.

The embodiment of the invention not only discloses the device for the active/standby power switching control, but also discloses the method for the active/standby power switching control, the method comprising:

Specifically, when the voltage is detected to be normal, the hysteresis control module receives the indication signal of the normal voltage and sends the hysteresis signal; when the over-under-voltage detection module receives the hysteresis signal, the undervoltage point is lowered from the original under-voltage point. To the undervoltage detection hysteresis switching point, or to raise the overvoltage point from the original overvoltage point to the overvoltage detection hysteresis switching point, or to reduce the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point, and Increase the overvoltage point from the original overvoltage point to the overvoltage detection hysteresis switching point. The normal voltage indication signal is transmitted to the main circuit power switch and the backup power switch, and the control main power switch supplies the main power to the load, and the backup power switch controls the backup power supply provided to the load.

When a voltage abnormality is detected, the hysteresis control module receives an indication signal of a voltage abnormality, but does not transmit a hysteresis signal. The indication signal of the abnormal voltage is transmitted to the main circuit power switch and the backup power switch, the main power switch is controlled to cut off the main power supply provided to the load, and the backup power switch is provided to supply the backup power to the load; and the undervoltage point is set in the original At the undervoltage point, set the overvoltage point to the original overvoltage point.

The main circuit power switch module can use a MOS switch.

The method may further include: displaying a status when the main power source is normally powered. When the main power supply voltage overvoltage or undervoltage is detected, the status of the main circuit is abnormal.

In the embodiment of the present invention, the overvoltage and undervoltage detection module not only performs undervoltage detection on the main power supply, but also performs overvoltage detection on the main power supply. When the main power supply is abnormal, that is, the main power supply is lower than the undervoltage point or higher than the overvoltage point, Both switch from primary power to backup power. Thereby, the switching control of the active and standby power sources is further improved, and the load is normally powered more efficiently.

Moreover, compared with the prior art, the scheme of the active/standby power switching control of the embodiment of the present invention further has the following advantages:

1) In the prior art, since the main power switch module uses a diode combination to supply power to the load, the voltage loss of the power supply is large due to the characteristics of the diode itself, and the power consumption is large. In the embodiment of the present invention, when the main power switch module is implemented by the MOS switch, the MOS switch is turned on to supply the main power to the load, and the internal resistance of the MOS switch is small, the voltage loss is small, and the power consumption is reduced.

2) Since the main components of the circuit of the prior art main-supply switching control device use two dedicated chips: the hot-swappable chip LT1422 and the voltage monitoring chip MC33161, which leads to relatively high cost. Moreover, there are relatively many types of main devices in the prior art: In addition to two kinds of dedicated chips, there is one power NMOS transistor, one power PMOS and one diode, which will also lead to an increase in cost. In the embodiment of the present invention, the circuit of the main power supply switching control is implemented by a conventional and general-purpose device, and the cost thereof is mainly represented by the cost of the TL431 and the MOS switch, and the cost of the TL431 and the MOS switch is smaller than that of the dedicated chip (the hot-swappable chip LT1422). The voltage monitoring chip MC33161) is much lower, thus reducing the cost.

Moreover, in the embodiment of the present invention, the main function of the main power supply switching control circuit is less, and the normalization of the device type also brings a cost advantage, thereby further reducing the cost.

3) For the difference of power and voltage required by the load, only the MOS switch for realizing the main power switch module, the MOS switch for realizing the backup power switch module, and the MOS for implementing the backup power switch module need to be adjusted. The switch can meet the requirements and is easy to use.

The above described specific embodiments of the present invention are further described in detail, and are intended to be illustrative of the embodiments of the present invention. The scope of the protection, any modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Claim

A device for switching control of active and standby power sources, comprising:

The over-undervoltage detection module is configured to perform over-voltage detection on the main power supply voltage, and detect an indication signal that the output voltage is normal when the voltage is normal; and an indication signal that the output voltage is abnormal when a voltage over-voltage or under-voltage is detected;

The main circuit power switch module provides a main power supply to the load when receiving the indication signal of the normal voltage transmitted by the over-undervoltage detection module; receiving an indication signal indicating that the voltage is abnormally transmitted by the over-undervoltage detection module When the main power supply to the load is cut off;

The standby path control module provides backup power to the load when receiving the indication signal of the abnormal voltage transmitted by the over-voltage detecting module; and receiving the indication signal of the normal voltage transmitted by the over-voltage detecting module , cut off the backup power supplied to the load.

2. The device of the active/standby power switching control according to claim 1, further comprising: a backup path slow-up module, configured to slowly transmit the backup power to the backup path control module;

The standby slow-start module includes a backup slow-start power switch module and a backup anti-shake and slow-start module; the standby anti-shake and slow-start module is configured to control the anti-jitter ground of the backup slow-start power switch module Slowly transfer the backup power to the backup control module;

The standby circuit power switch module is configured to transmit the backup power source to the backup path control module under the control of the standby anti-shake and slow-start module.

The device of the active/standby power switching control according to claim 1, further comprising a hysteresis control module, configured to receive an indication signal that the voltage transmitted by the over-voltage detecting module is normal, to the The undervoltage detection module sends a hysteresis signal;

The overvoltage and undervoltage detection module reduces the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point according to the received hysteresis signal; or, the overvoltage point is raised from the original overvoltage point to the overvoltage Detect the hysteresis switching point; or, reduce the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point, and raise the overvoltage point from the original overvoltage point to the overvoltage detection hysteresis switching point.

4. The apparatus for switching between active and standby power sources according to claim 1, wherein said preparation path The control module includes a backup power switch control module and a backup power switch module;

The standby power switch control module is configured to control the backup power switch module to provide backup power to the load when receiving the indication signal of the abnormal voltage transmitted by the overvoltage and undervoltage detection module; When the voltage indication signal transmitted by the undervoltage detection module is normal, controlling the backup power switch module to cut off the backup power supply provided to the load;

The backup power switch module is configured to provide backup power to the load under the control of the backup power switch control module, or cut off the backup power provided to the load.

The apparatus for switching between active and standby power sources according to claim 2, wherein the standby mode restart module is implemented by a separate component.

The apparatus for switching between active and standby power sources according to claim 1, wherein the main power switch module is a MOS switch.

The device of the active/standby power supply switching control according to claim 1, further comprising a circuit abnormality display module, configured to: after receiving the indication signal of the abnormal voltage output by the overvoltage and undervoltage detection module, displaying the main road abnormality status.

8. A method for switching control of active and standby power sources, comprising:

An indication signal indicating that the output voltage is abnormal when the main power supply voltage is overvoltage or undervoltage is detected, and the backup power switch controls the backup power supply to the load.

The method according to claim 8, further comprising: receiving an indication signal that the voltage is normal when the voltage is normal, and transmitting a hysteresis signal; and detecting the voltage abnormality, receiving the voltage Abnormal indication signal, no hysteresis signal is sent.

10. The method according to claim 9, further comprising: reducing the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point when receiving the hysteresis signal , or, raise the overvoltage point from the original overvoltage point to the overvoltage detection hysteresis switching point, or reduce the undervoltage point from the original undervoltage point to the undervoltage detection hysteresis switching point, and pass the overvoltage point from the original Pressure point up to overpressure check Measure the hysteresis switching point.

The method of the active/standby power switching control according to claim 9 or 10, further comprising:

When the main power supply voltage overvoltage or undervoltage is detected, the status of the main circuit is abnormal.