CN220291721U - Power supply switching device for switching device and switching device - Google Patents

Abstract

The embodiment of the disclosure provides a power switching device for a switching device and the switching device. The power switching device includes: a main switch assembly coupled between a main power source and a load and including a main control terminal; an auxiliary switch assembly coupled between the backup power source and the load and including a first field effect transistor and a second field effect transistor, the gates of the first field effect transistor and the second field effect transistor being coupled together to form an auxiliary control terminal; the power supply monitoring circuit comprises a control signal output end, and the control signal output end is coupled to an auxiliary control terminal of the auxiliary switch assembly; and an inverting circuit coupled between the control signal output terminal and the main control terminal and adapted to invert the signal output by the control signal output terminal and provide the inverted signal to the main control terminal, and an output terminal of the inverting circuit is further coupled to drains of the first field effect transistor and the second field effect transistor. Therefore, the response time of power supply switching can be reduced, and the normal operation of the load is ensured.

Description

Power supply switching device for switching device and switching device

Technical Field

Example embodiments of the present disclosure relate generally to the field of switching devices, and in particular, to a power switching device for a switching device and a switching device.

Background

In a switchgear such as an air switch, in order to ensure that a trip record can be maintained after power failure, the trip mechanism typically uses dual power supplies, one of which is provided by a main line through a coil, and the other of which is a backup power supply, typically a lithium battery. The system power uses a battery or power supply depending on whether the coil power is normal or not, so there will be a battery-power switching. The life of the battery involves a requirement of at least 10 years. The aging internal resistance of the battery becomes large during the use process, and the voltage drop on the battery switching path needs to be considered for the design of long service life. However, the existing products still use diodes as effective measures for switching current backflow prevention, so that various problems such as stable voltage output, backflow current and the like cannot be guaranteed.

Disclosure of Invention

It is an object of the present disclosure to provide a power switching device and a switching device for a switching device that at least partially address the above-mentioned problems and/or other potential problems present in conventional switching devices.

In a first aspect of the present disclosure, a power switching device for a switching device is provided. The power switching device includes: a main switch assembly coupled between a main power source and a load and including a main control terminal; an auxiliary switch assembly coupled between the backup power source and the load and including a first field effect transistor and a second field effect transistor, the gates of the first field effect transistor and the second field effect transistor being coupled together to form an auxiliary control terminal; the power supply monitoring circuit comprises a control signal output end, and the control signal output end is coupled to an auxiliary control terminal of the auxiliary switch assembly; and an inverting circuit coupled between the control signal output terminal and the main control terminal and adapted to invert the signal output by the control signal output terminal and provide the inverted signal to the main control terminal, and an output terminal of the inverting circuit is further coupled to drains of the first field effect transistor and the second field effect transistor.

In the embodiment of the disclosure, the first field effect transistor and the second field effect transistor are coupled back to back and are coupled between the standby power supply and the load, so that current backflow caused during power supply switching can be avoided, the negative influence of backflow current on the standby power supply is eliminated, and meanwhile, the problem of overlarge voltage drop of a power supply branch of the standby power supply can be solved. Other benefits will be described below in connection with the corresponding embodiments.

In some embodiments, the power switching device further comprises: and a first resistor coupled between the output of the inverting circuit and the drains of the first and second field effect transistors.

In some embodiments, the inverting circuit includes: the gate of the third field effect transistor is coupled to the control signal output terminal, the source is grounded, and the second resistor is coupled between the main control terminal and the drain of the third field effect transistor.

In some embodiments, the main switch assembly includes: a fourth field effect transistor having a gate as a main control terminal, a source coupled to the load, and a drain coupled to the main power supply.

In some embodiments, the first field effect transistor and the second field effect transistor each comprise a P-channel metal-oxide-semiconductor field effect transistor, and the source of the first field effect transistor is coupled to the standby power supply and the source of the second field effect transistor is coupled to the load.

In some embodiments, the first resistor has a resistance value of 0 to 200Ω.

In some embodiments, the second resistor has a resistance greater than 1kΩ.

In some embodiments, the fourth field effect transistor comprises a P-channel metal-oxide-semiconductor field effect transistor.

In some embodiments, the third field effect transistor comprises an N-channel metal-oxide-semiconductor field effect transistor.

In some embodiments, the power switching device further comprises a schottky diode. The anode of the schottky diode is coupled between the drain of the fourth field effect transistor and the main power supply and the cathode is coupled between the source of the fourth field effect transistor and the load.

In a second aspect of the present disclosure, a switching device is provided. The switching device includes: the tripping mechanism is used for controlling the switching device to realize tripping; a load for storing and/or indicating at least the state of the switching device; a main power supply and a standby power supply coupled to the trip mechanism and the load; and the power switching device according to the first aspect is configured to selectively switch on the main power supply or the standby power supply to supply power to the load.

It should be understood that what is described in this section of the disclosure is not intended to limit key features or essential features of the embodiments of the disclosure, nor is it intended to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, wherein like or similar reference numerals denote like or similar elements, in which:

fig. 1 illustrates an architectural schematic diagram of a power switching device according to some embodiments of the present disclosure;

fig. 2 illustrates a circuit schematic of a power switching device according to some embodiments of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure have been illustrated in the accompanying drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will be more thorough and complete. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In describing embodiments of the present disclosure, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions are also possible below. The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.

As mentioned briefly above, in switching devices such as air switches, a battery backup may be used to power a load such as a microprocessor, indicator lights, etc. For example, when a fault such as an electrical leakage, an arc, or the like exists in the circuit and is tripped, the microprocessor, the indicator lamp, or the like can still record and indicate the cause of the fault by supplying power from the standby battery.

When two independent main/backup power sources are used, conventional switching devices, some loads such as microprocessors or indicator lights in the switching devices need to quickly draw energy from the backup power source (e.g., backup battery) to maintain operation when the main power source fails (e.g., trips or fails). However, in practical applications, a large voltage drop may occur in the power supply branch of the backup battery due to unavoidable factors such as impedance of the lead, aging of the connection components and the battery, and the like. For example, when the standby power supply (such as a battery) supplies power, the voltage drop is 0.45V in the worst case, and the load circuit needs 2.5V minimum voltage to start working, at this time, the standby power supply needs to ensure 2.9V working current output to enable the load to operate normally. However, it is difficult to ensure that the backup battery can continuously and stably output a voltage of 2.9V in practical cases. If the voltage drop cannot be reduced, the battery life expectancy is greatly compromised.

The conventional switching device has a backflow phenomenon which occurs when the standby power is switched to the main power. When the main power supply is restored and then the power supply loop of the switching device is re-connected, the components in the high state (ON) or the low state (OFF) can cause current to reversely pass through other components, and the current backflow phenomenon can cause damage to the standby power supply. For example, a backup power supply coupled diode prevents current from flowing backward when switching, and current flowing backward occurs, so that the battery is aged rapidly.

To solve or at least partially solve the above-described problems or other potential problems with conventional switching devices, embodiments of the present disclosure provide a power switching device solution for switching devices such as air switches. In the power supply switching device, a voltage signal of a main power supply is identified through a power supply monitoring circuit and a control signal is generated and used for controlling an inverter circuit and an auxiliary control terminal so as to drive the on-off of a main switch assembly and an auxiliary switch assembly. The auxiliary switch assembly is coupled back-to-back through the first and second field effect transistors and couples the first and second field effect transistors between the backup power source and the load. The characteristic of low-resistance characteristics of the first field effect transistor and the second field effect transistor after being conducted is utilized to realize the characteristic of low voltage difference of the power supply branch of the standby power supply, so that the problem of overlarge voltage drop of the power supply branch of the standby power supply can be solved, meanwhile, current backflow caused during power supply switching can be prevented, and backflow current in the embodiment of the utility model is less than 100uA, so that damage of backflow current to a battery is eliminated.

An example architecture and operation of the power switching device of the switching device will be described below in connection with fig. 1-2. A switching device according to an embodiment of the present disclosure may include a trip mechanism, a load such as a microprocessor and/or an indicator, a main power supply, a backup power supply, and a power switching device. The trip mechanism is used to control the switching device to trip (again referred to as trip) when the connected main circuit fails. A load such as a microprocessor and/or an indicator is used to store and/or indicate the state of the switching device. The main power supply (e.g., operating voltage 3.3V) is typically coupled to the main loop through a coil to power the trip mechanism, etc. The backup power source (e.g., operating voltage 3.3V) is typically a backup battery and is coupled to the trip mechanism. The power switching device is used for selectively switching on the main power supply or the standby power supply to supply power to the load. For example, after the switching device is tripped, a load such as a microprocessor and/or an indicator is powered by the backup battery. The microprocessor can store the cause of the fault and indicate it on an indicator.

As shown in fig. 1, a power switching device according to an embodiment of the present disclosure generally includes a main switch assembly, an auxiliary switch assembly, a power monitoring circuit 160, and an inverter circuit. In some embodiments, the power switching device further includes a first resistor 170 and a schottky diode 150. For example, a main switch assembly is coupled between the main power supply and the load, an auxiliary switch assembly is coupled between the backup power supply and the load, and a power monitoring circuit 160 is coupled to the auxiliary switch assembly, and an inverter circuit is coupled between the power monitoring circuit 160 and the main switch assembly. In the embodiment of the present disclosure, the first resistor 170 is coupled between the auxiliary switch component and the inverter circuit, so that the fourth field effect transistor 140 and the first field effect transistor 110 and the second field effect transistor 120 can implement mutually exclusive control, and a specific implementation will be described below. When the standby power supply is started, before the main power supply completely stops working, the main power supply can continue to supply power to the load through the Schottky diode 150 until the standby power supply reaches the power supply requirement of the load, and then the main power supply stops supplying power. Therefore, the power supply switching device can realize high-efficiency and reliable automatic seamless switching between the main power supply and the standby power supply, can effectively limit the backward current and ensure continuous operation of the load.

A specific circuit configuration of the power switching device will be described below with reference to fig. 1 and 2. As shown in fig. 1 and 2, in an embodiment of the present disclosure, the main switch assembly includes a main control terminal, for example, the main switch assembly includes a fourth field effect transistor 140 having a gate as the main control terminal, a source coupled to a load, and a drain coupled to a main power supply. In some embodiments, the fourth field effect transistor 140 may be a P-channel metal-oxide-semiconductor field effect transistor (also referred to as a P-MOSFET or PMOS transistor). Referring to fig. 2, the main switching assembly further includes a resistor 141 and a resistor 142, the drain of the fourth field effect transistor 140 is coupled to the main power supply through the resistor 141, the source is coupled to the load through the resistor 142 and the resistor 190, and the gate is coupled to the inverter circuit as a main control terminal.

In an embodiment of the present disclosure, as mentioned previously, the auxiliary switch assembly includes a first field effect transistor 110 and a second field effect transistor 120. The gates of the first field effect transistor 110 and the second field effect transistor 120 are coupled together to form an auxiliary control terminal. The source of the first field effect transistor 110 is coupled to a standby power supply and the source of the second field effect transistor 120 is coupled to a load. The first field effect transistor 110 and the second field effect transistor 120 may employ P-channel type metal-oxide-semiconductor field effect transistors (may also be referred to as P-MOSFETs or PMOS transistors). For example, referring to fig. 2, the source of the first field effect transistor 110 is coupled to a standby power supply via a resistor 111. The source of the second field effect transistor 120 is coupled to a load via a resistor 190.

Next, in an embodiment of the present disclosure, the power supply monitoring circuit 160 includes a control signal output coupled to the auxiliary control terminal of the auxiliary switch assembly such that the inverting circuit is coupled between the control signal output and the main control terminal and is adapted to invert the signal output by the control signal output and provide it to the main control terminal. The power supply monitoring circuit 160 is configured to detect whether the voltage of the main power supply reaches a preset threshold value, so as to switch between the main power supply and the standby power supply. And when the voltage of the main power supply is smaller than a preset threshold value, the standby power supply is turned on, and the main power supply is turned off. When the voltage of the main power supply is greater than the preset threshold, the standby power supply is turned off, and the main power supply is turned on, and the specific implementation will be described in detail below. In some embodiments, the preset threshold of the main power supply port may be 0-3V. The output of the inverting circuit is also coupled to the drains of the first field effect transistor 110 and the second field effect transistor 120. As shown in fig. 2, the control signal output is coupled to the auxiliary control terminal of the auxiliary switch assembly and the inverter circuit via resistor 161. In some embodiments, the inverter circuit includes a third field effect transistor 130 and a second resistor 180, the gate of the third field effect transistor 130 is coupled to the control signal output terminal, the source is connected to the virtual ground (e.g. GND terminal) of the circuit board, and the second resistor 180 is coupled between the main control terminal and the drain of the third field effect transistor 130. For example, the third field effect transistor 130 may include an N-channel metal-oxide-semiconductor field effect transistor (may also be referred to as an N-MOSFET or an NMOS transistor). In some embodiments, the resistance of the second resistor 180 may be a resistor greater than 1kΩ, for example, 10kΩ, 20kΩ, or 30kΩ may be used, which is not particularly limited by the embodiments of the disclosure.

In an embodiment of the present disclosure, a first resistor 170 is coupled between the output of the inverting circuit and the drains of the first field effect transistor 110 and the second field effect transistor 120. The drains of the first field effect transistor 110 and the second field effect transistor 120 are coupled to each other, that is, a circuit structure in which the first field effect transistor 110 and the second field effect transistor 120 are coupled back to back is implemented, so as to effectively prevent current flowing backward after the main power supply is started. Such a circuit configuration in which the first field effect transistor 110 and the second field effect transistor 120 are coupled back-to-back may also be referred to as an anti-parallel or anti-parallel connection. In some embodiments, the resistance of the first resistor 170 may be 0 to 200Ω, for example, 10Ω, 20Ω, 50Ω, 80Ω, 120Ω, 150Ω, or 180Ω may be used, which is not particularly limited in the embodiments of the disclosure.

In an embodiment of the present disclosure, the anode of the schottky diode 150 is coupled between the drain of the fourth field effect transistor 140 and the main power supply, and the cathode is coupled between the source of the fourth field effect transistor 140 and the load. The schottky diode 150 is used for supplying power to the load through the schottky diode 150 before the main power supply completely stops working before the load reaches the working voltage because the standby power supply cannot immediately output the working voltage reaching the load in a short time in the process from starting to completely supplying power to the load. For example, referring to fig. 2, the anode of schottky diode 150 is coupled between the drain of fourth field effect transistor 140 and the main power supply, and the cathode thereof is coupled between resistor 142 and resistor 190.

In order to more clearly understand the operation of the power switching device according to the embodiment of the present disclosure, an example of the power switching device is described below with reference to fig. 1 and 2. The power supply switching device mainly comprises 3 PMOS tubes, 1 NMOS tube and 2 resistors. And will not be described in detail here.

The power switching device according to the embodiment of the present disclosure includes a main power supply circuit and a standby power supply circuit (hereinafter referred to as a main circuit and a standby circuit). When operating normally, the main loop is connected to the load and is powered by the main power supply. At the same time, the backup circuit remains open. When the main power supply is interrupted or fails, the power supply monitoring circuit 160 of the power supply switching device monitors the situation and rapidly switches the load from the main loop to the standby loop. When the main circuit is powered up again, the standby circuit is transitioned to the off state. During switching, the power switching device can ensure smooth transition and stable energy transmission to avoid influencing the load. Therefore, the working process of the power switching device of the embodiment of the present disclosure is analyzed in the following three cases.

Referring to FIG. 2, V ₁ Control port for main power signal of power supply monitoring circuit 160, V ₂ The power supply voltage is recorded as V for the power supply port of the standby power supply _aux ，V ₃ The power supply voltage is recorded as V for the power supply port of the main power supply _main ，V ₄ For connecting the output port of the load, the output voltage is denoted as V _out . When the main power supply is at the power supply port V ₃ When power is supplied, the output port V ₄ The power supply port V is supplied by a main power supply ₃ And outputting power supply. When the main power supply is at the power supply port V ₃ When power is off, the power supply port V of the standby power supply is automatically switched ₂ And (5) supplying power.

1. When the main power supply is at the power supply port V ₃ Restoring power supply, standby power supply port V ₂ No power is supplied.

When the main power supply is at the power supply port V ₃ Is set to the input voltage V of _main Through the body diode output of the fourth field effect transistor 140. Main power supply signal control port V ₁ Is provided with a detection main power supply port V ₃ Is set to the input voltage V of _main Is a high level signal, and the gate voltage (V _g ) Is greater than the source voltage (V) _s ) Thereby being in a conductive state, so that the drain voltage (V _d ) Pulled low and through the third field effect transistor 130A resistor 180 of large resistance (e.g., resistance greater than 1kΩ) is coupled between the drain and the gate of the fourth field effect transistor 140 for voltage drop. Therefore, the gate (G-pole) of the fourth field effect transistor 140 is simultaneously enabled to be a low level signal, so that the fourth field effect transistor 140 is turned on to enable the main loop to supply power.

Next, the states of the first field effect transistor 110 and the second field effect transistor 120 will be described, since the gate voltage (V _g ) Is a high signal so that the gates of the first field effect transistor 110 and the second field effect transistor 120 are in a high signal and are in an off state. Thus, the output voltage of the output port is not supplied to the output through the backup loop. It should be noted here that, due to the presence of the second resistor 180, the turn-on process of the fourth field effect transistor 140 is delayed from the turn-off process of the first field effect transistor 110 and the second field effect transistor 120 after the main power is restored. In other words, the turn-off process of the first field effect transistor 110 and the second field effect transistor 120 is faster.

2. When the main power supply is at the power supply port V ₃ Power supply port V of standby power supply without power supply ₂ And (5) supplying power.

When the main power signal controls the port V ₁ Is provided with a detection main power supply port V ₃ Is set to the input voltage V of _main When the threshold value is smaller than the preset threshold value, the gate voltage (V _g ) Is a low level signal so that the gates of the first field effect transistor 110 and the second field effect transistor 120 are in a low level signal, and are in an on state, while the third field effect transistor 130 and the fourth field effect transistor 140 are in an off state. So output port V ₄ Output voltage V of (2) _out At the same time through the standby loop and the main power supply port V ₃ Output port V is provided via schottky diode 150 ₄ And (5) supplying power and outputting. Until the standby loop reaches the output voltage V ₄ After that, the main loop stops supplying power.

Standby power supply port V ₂ Is set to the supply voltage V of _aux Body diode through first field effect transistor 110 and second field effect transistor 120Tube output voltage, i.e. V _out ＝V _aux -V _ds ，V _ds As the voltage drop of the body diodes of the first field effect transistor 110 and the second field effect transistor 120, the maximum resistance value of the first field effect transistor 110 and the second field effect transistor 120 is 0.2 Ω, i.e. V _out ≈V _aux . Therefore, the problem that the voltage drop of the standby loop is overlarge and the power supply requirement of a load cannot be met when the power supply of the existing switching device is switched can be solved. In some embodiments, the first resistor 170 is coupled between the gate of the fourth field effect transistor 140 and the drains of the first field effect transistor 110 and the second field effect transistor 120, and since the resistance of the first resistor 170 is smaller, the high-level signal of the first field effect transistor 110 directly acts on the gate of the fourth field effect transistor 140 through the first resistor 170, so that the fourth field effect transistor 140 does not have a conducting voltage difference and is in a state close to the off state, and thus the transient reverse current is smaller.

3. When the main power supply is at the power supply port V ₃ Electrifying again, and supplying power to the port V by the standby power supply ₂ Switching to the off state.

When the main power signal controls the port V ₁ Is provided with a detection main power supply port V ₃ Is set to the input voltage V of _main When the threshold is greater than the preset threshold, the gate voltage (V _g ) Is a high level signal, so that the gates of the first field effect transistor 110 and the second field effect transistor 120 are located in a high level signal, and are in an off state, and the third field effect transistor 130 and the fourth field effect transistor 140 are in an on state, which is similar to the first case and is not described herein.

The states of the first field effect transistor 110 and the second field effect transistor 120 are described, since the gate voltage (V _g ) Is a high signal so that the gates of the first field effect transistor 110 and the second field effect transistor 120 are in a high signal and are in an off state. The output voltage of the output port is not supplied to the output through the backup loop. In this case, the main loop is in the second FET 120The leakage current is guided to the virtual ground (e.g., GND terminal) of the circuit board through the third fet 130, so that the leakage current can be prevented from flowing backward into the standby power supply and the accelerated aging of the battery can be prevented.

The three conditions are that the power supply switching device mainly uses the main power supply port V ₃ Power supply output to output port V ₄ And (5) supplying power. When the main power supply is at the power supply port V ₃ Power supply port V of standby power supply during power failure ₂ Output to output port V ₄ And (5) supplying power. Thereby realizing the function of automatically switching the power supply with low voltage drop of the power supply switching device.

The foregoing description of implementations of the present disclosure has been provided for illustrative purposes, is not exhaustive, and is not limited to the implementations disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various implementations described. The terminology used herein was chosen in order to best explain the principles of each implementation, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand each implementation disclosed herein.

Claims (9)

1. A power switching device for a switching device, comprising:

a main switch assembly coupled between a main power source and a load and including a main control terminal;

an auxiliary switch assembly coupled between a backup power source and a load and comprising a first field effect transistor (110) and a second field effect transistor (120), the gates of the first field effect transistor (110) and the second field effect transistor (120) being coupled together to form an auxiliary control terminal;

a power supply monitoring circuit (160) comprising a control signal output coupled to the auxiliary control terminal of the auxiliary switch assembly; and

-an inverting circuit coupled between the control signal output and the main control terminal and adapted to invert the signal output by the control signal output and provide it to the main control terminal, and the output of the inverting circuit is further coupled to the drains of the first field effect transistor (110) and the second field effect transistor (120).

2. The power switching device according to claim 1, further comprising:

a first resistor (170) coupled between an output of the inverting circuit and the drains of the first and second field effect transistors (110, 120).

3. The power switching device according to claim 1, wherein the inverter circuit includes:

-a third field effect transistor (130) and-a second resistor (180), the gate of the third field effect transistor (130) being coupled to the control signal output, the source being grounded, and the second resistor (180) being coupled between the main control terminal and the drain of the third field effect transistor (130).

4. A power switching device according to any one of claims 1 to 3, wherein the main switch assembly comprises:

-a fourth field effect transistor (140), the gate of the fourth field effect transistor (140) acting as the main control terminal, the source being coupled to the load and the drain being coupled to the main power supply.

5. A power switching device according to any of claims 1-3, characterized in that the first field effect transistor (110) and the second field effect transistor (120) each comprise a P-channel metal-oxide-semiconductor field effect transistor, and that the source of the first field effect transistor (110) is coupled to the standby power supply and the source of the second field effect transistor (120) is coupled to the load.

6. The power switching device of claim 4, wherein the fourth field effect transistor (140) comprises a P-channel metal-oxide-semiconductor field effect transistor.

7. A power switching device according to claim 3, wherein the third field effect transistor (130) comprises an N-channel metal-oxide-semiconductor field effect transistor.

8. The power switching device according to claim 4, further comprising:

-a schottky diode (150), the anode of the schottky diode (150) being coupled between the drain of the fourth field effect transistor (140) and the main power supply, and the cathode being coupled between the source of the fourth field effect transistor (140) and the load.

9. A switching device, comprising:

the tripping mechanism is used for controlling the switching device to realize tripping;

a load for storing and/or indicating at least the state of the switching device;

a main power supply and a backup power supply coupled to the trip mechanism and the load; and

the power switching device of any of claims 1-8, configured to selectively turn on the primary power source or the backup power source to power the load.