CN211958854U - Power supply switching circuit - Google Patents
Power supply switching circuit Download PDFInfo
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- CN211958854U CN211958854U CN202020288688.9U CN202020288688U CN211958854U CN 211958854 U CN211958854 U CN 211958854U CN 202020288688 U CN202020288688 U CN 202020288688U CN 211958854 U CN211958854 U CN 211958854U
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Abstract
The utility model relates to a power supply switching circuit, include: the first power supply input circuit is used for being electrically connected with a first power supply, converting an output signal of the first power supply and outputting a first power supply signal; the second power supply input circuit is used for being electrically connected with a second power supply and outputting a second power supply signal after converting an output signal of the second power supply, and the output end of the second power supply input circuit and the output end of the first power supply input circuit are both used for being electrically connected with the output end of the working power supply; and the switching detection circuit is electrically connected with the output end of the second power input circuit and the control end of the first power input circuit and is used for outputting a switching control signal to drive the first power input circuit to switch off and output when detecting that the second power input circuit outputs a second power signal, so that the first power signal is output to the working power output end and is switched to the second power signal to be output to the working power output end. The utility model discloses can realize the seamless switching of two powers, improve power efficiency and reliability.
Description
Technical Field
The utility model relates to a power technical field especially relates to a power supply switching circuit.
Background
In the field of power supply technology, input voltage can be divided into alternating current and direct current, and the direct current also includes DC28V, DC48V, DC110V, DC160V, DC270V and the like, and with the development of technology, a single voltage input is difficult to meet the requirements of electric equipment, so that technologies of dual power supply input, power supply management circuits and the like capable of providing different voltages for the electric equipment are developed.
In a traditional dual-input power supply, generally, the power supply is not switched, two input voltages are directly and simultaneously connected to a power supply circuit, and the two input voltages are selected through a power regulator. However, this method is difficult to realize seamless switching, and the input power supply is switched to have a voltage drop phenomenon, so that the power supply is not stable enough. In some cases, two power supply circuits are directly connected to the electric equipment in an OR gate circuit mode, and the two power supply circuits are not switched and controlled, so that the power supply efficiency and reliability are reduced.
SUMMERY OF THE UTILITY MODEL
Accordingly, there is a need for a power switching circuit that can improve power efficiency and reliability.
A power switching circuit, comprising:
the first power supply input circuit is used for being electrically connected with a first power supply, converting an output signal of the first power supply and outputting a first power supply signal;
the second power supply input circuit is used for being electrically connected with a second power supply and outputting a second power supply signal after converting an output signal of the second power supply, and the output end of the second power supply input circuit and the output end of the first power supply input circuit are both used for being electrically connected with the output end of the working power supply;
and the switching detection circuit is electrically connected with the output end of the second power input circuit and the control end of the first power input circuit and is used for outputting a switching control signal to drive the first power input circuit to switch off and output when detecting that the second power input circuit outputs a second power signal, so that the first power signal is output to the working power output end and is switched to the second power signal to be output to the working power output end.
In one embodiment, the power switching circuit further includes:
the input end of the first unidirectional output circuit is electrically connected with the output end of the first power supply input circuit, and the output end of the first unidirectional output circuit is electrically connected with the output end of the working power supply and is used for preventing a second power supply signal from flowing backwards to the first power supply;
and the input end of the second unidirectional output circuit is electrically connected with the output end of the second power input circuit, and the output end of the second unidirectional output circuit is electrically connected with the output end of the working power supply and is used for preventing the first power supply signal from flowing backwards to the second power supply.
In one embodiment, the switching detection circuit includes:
the voltage sampling circuit is used for sampling the output voltage of the second power output circuit and outputting a sampling signal;
and the driving circuit is electrically connected with the voltage sampling circuit and used for outputting a driving signal when a second power supply signal is output to the second power supply output circuit according to the sampling signal, and the driving signal is used for driving the first power supply output circuit to be switched off and output.
In one embodiment, the voltage sampling circuit comprises: a first resistor, a second resistor and a third resistor; the drive circuit includes: a first N-channel field effect transistor and an optical coupler;
the first end of the first resistor is used as the input end of the switching detection circuit and is electrically connected with the first power input circuit, and the second end of the first resistor is electrically connected with the first end of the second resistor;
the second end of the second resistor is grounded;
the first end of the third resistor is electrically connected with the first end of the first end circuit, and the second end of the third resistor is electrically connected with the anode of the light emitting diode of the optocoupler;
the drain electrode of the first N-channel field effect transistor is electrically connected with the cathode of the light-emitting diode of the optocoupler, the grid electrode of the first N-channel field effect transistor is electrically connected with the second end of the first resistor, and the source electrode of the first N-channel field effect transistor is grounded;
and the collector electrode of the phototriode of the optocoupler is used as a first potential of the driving signal output end, and the emitter electrode of the phototriode of the optocoupler is used as a second potential of the driving signal output end and is used for outputting a driving signal to the controlled end of the first power input circuit when the phototriode of the optocoupler is switched on.
In one embodiment, the first unidirectional output circuit includes: the first current flows to the controller and the second N-channel field effect transistor;
the first current flow direction controller comprises a power supply end, a first voltage input end, a second voltage input end, a control signal output end and a grounding end, the power supply end and the first voltage input end of the first current flow direction controller are both electrically connected with the output end of the first power supply input circuit, the second voltage input end of the first current flow direction controller is electrically connected with the output end of the working power supply, and the grounding end is grounded;
the source electrode of the second N-channel field effect transistor is electrically connected with the output end of the first power supply input circuit, and the drain electrode of the second N-channel field effect transistor is electrically connected with the output end of the working power supply; the grid is electrically connected with the control signal output end of the first current flow direction controller.
In one embodiment, the first unidirectional output circuit further comprises: a first capacitor;
the first end of the first capacitor is electrically connected with a power supply end of the first current flowing to the controller, and the second end of the first capacitor is grounded.
In one embodiment, the second unidirectional output circuit includes: the second current flows to the controller and the third N-channel field effect transistor;
the second current flow direction controller comprises a power supply end, a first voltage input end, a second voltage input end, a control signal output end and a grounding end, the power supply end and the first voltage input end of the second current flow direction controller are both electrically connected with the output end of the second power supply input circuit, the second voltage input end of the second current flow direction controller is electrically connected with the output end of the working power supply, and the grounding end is grounded;
the source electrode of the third N-channel field effect transistor is electrically connected with the output end of the second power supply input circuit, and the drain electrode of the third N-channel field effect transistor is electrically connected with the output end of the working power supply; the grid is electrically connected with the control signal output end of the second current flow direction controller.
In one embodiment, the second unidirectional output circuit further comprises: a second capacitor;
the first end of the second capacitor is electrically connected with the power supply end of the second current flowing to the controller, and the second end of the second capacitor is grounded.
In one embodiment, the first power input circuit and the second power input circuit each include:
an input filter circuit for filtering the output signal of the first power supply/the second power supply;
and the DC/DC conversion circuit is used for carrying out isolation conversion on the voltage output by the input filter circuit and converting the voltage into a first power supply signal/a second power supply signal.
In one embodiment, the power switching circuit further includes:
and the output filter circuit is electrically connected with the first power input circuit and the second power input circuit and is used for filtering the first power signal or the second power signal and then outputting a working power signal.
The power supply switching circuit respectively processes signals of the two power supplies through the first power supply input circuit and the second power supply input circuit and outputs the processed signals to the working power supply output end, the switching detection circuit is used for detecting output signals of the second power supply input circuit, and if the second power supply input circuit is detected to output second power supply signals, the switching detection circuit outputs switching control signals to the first power supply input circuit so as to drive the first power supply input circuit to stop outputting the first power supply signals, seamless switching of the two power supplies is achieved, and power supply efficiency and reliability are improved.
Drawings
FIG. 1 is a block diagram of a power switching circuit according to an embodiment;
FIG. 2 is a block diagram of a power switching circuit according to another embodiment;
FIG. 3 is a block diagram of a switch detect circuit according to one embodiment;
FIG. 4 is a schematic circuit diagram of a switching detection circuit according to an embodiment;
FIG. 5 is a schematic circuit diagram of a first unidirectional output circuit according to an embodiment;
FIG. 6 is a circuit diagram of a second unidirectional output circuit according to an embodiment.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described more fully below. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element and be integral therewith, or intervening elements may also be present. The terms "mounted," "one end," "the other end," and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In one embodiment, as shown in fig. 1, there is provided a power switching circuit including:
a first power input circuit 100, configured to be electrically connected to a first power supply, convert an output signal of the first power supply, and output a first power signal VO 1;
the second power input circuit 200 is electrically connected to a second power supply, and outputs a second power signal VO2 after converting an output signal of the second power supply, and an output end of the second power input circuit 200 and an output end of the first power input circuit 100 are both used for electrically connecting an output end of the working power supply;
the switching detection circuit 300 is electrically connected to the output terminal of the second power input circuit 200 and the control terminal of the first power input circuit 100, and configured to output a switching control signal to drive the first power input circuit 100 to turn off the output when detecting that the second power input circuit 200 outputs the second power signal VO2, so as to switch the first power signal VO1 from the working power output terminal to the second power signal VO2 and output the second power signal VO2 to the working power output terminal.
The first power input circuit 100 is configured to process an output signal of the first power source and convert the output signal into a power signal required by the electric device 400. The second power input circuit 200 is used for processing an output signal of the second power source and converting the output signal into a power signal required by the electric device 400. In one embodiment, the processing of the power output signal by the first power input circuit 100 and the second power input circuit 200 may include one or more of boosting, dropping, filtering, rectifying, and selecting according to the type and voltage level of the power source and the requirements of the powered device 400. The output end of the first power input circuit 100 and the output end of the second power input circuit 200 are both connected to the working power output end, and power is supplied to the electric device 400 through the working power output end.
The switching detection circuit 300 is configured to switch the first power input circuit 100 or the second power input circuit 200 to be connected to the working power output end, and when detecting that the second power input circuit 200 outputs the second power signal VO2, drive the first power input circuit 100 to turn off the output, that is, switch from the first power input circuit 100 to the second power input circuit 200; when the second power input circuit 200 is detected to stop outputting the second power signal VO2, the first power input circuit 100 is driven to be turned on, so as to implement seamless switching. In one embodiment, the first power source and the second power source may be a direct current power source and an alternating current power source, respectively. In one embodiment, the first power source and the second power source may be dc power sources of different voltages. In one embodiment, the first power source and the second power source may be different voltage AC power sources.
The power switching circuit respectively processes two power supplies through the first power input circuit 100 and the second power input circuit 200 and outputs the processed signals to the output end of the working power supply, the switching detection circuit 300 is used for detecting the output signal of the second power input circuit 200, if the second power input circuit 200 is detected to output the second power signal VO2, the switching detection circuit 300 outputs a switching control signal to the first power input circuit 100 to drive the first power input circuit 100 to stop outputting the first power signal VO1, seamless switching of the two power supplies is realized, switching of the power supplies can be carried out as required, the first power input circuit is cut off when necessary, heat loss is reduced, and power efficiency and reliability are improved.
In one embodiment, as shown in fig. 2, the power switching circuit further includes:
the input end of the first unidirectional output circuit 500 is electrically connected with the output end of the first power input circuit 100, and the output end of the first unidirectional output circuit is electrically connected with the output end of the working power supply, so that the second power signal VO2 is prevented from flowing backwards to the first power supply;
in the second unidirectional output circuit 600, an input end is electrically connected to the output end of the second power input circuit 200, and an output end is electrically connected to the output end of the working power supply, so as to prevent the first power signal VO1 from flowing backward to the second power supply.
Because the output end of the first power input circuit 100 and the output end of the second power input circuit 200 are both electrically connected to the output end of the working power supply, that is, the output end of the first power input circuit 100 is electrically connected to the output end of the second power input circuit 200, in order to prevent the mutual backward flow, the first unidirectional output circuit 500 is arranged at the output end of the first power input circuit 100, so as to prevent the second power signal VO2 output by the second power input circuit 200 from flowing to the first power supply through the first power input circuit 100; the second unidirectional output circuit 600 is disposed at the output terminal of the second power input circuit 200 to prevent the first power signal VO1 outputted from the first power input circuit 100 from flowing to the second power through the second power input circuit 200. The first power input circuit and the second power input circuit are connected to the output end of the working power supply in an OR gate circuit mode through the first unidirectional output circuit and the second unidirectional output circuit respectively, and switching control between the first power input circuit and the second power input circuit is performed in a matching mode through the switching detection circuit, so that voltage output to electric equipment in a switching process is kept stable, and seamless switching is achieved.
In one embodiment, as shown in fig. 3, the switching detection circuit 300 includes:
the voltage sampling circuit 310 is used for sampling the output voltage of the second power output circuit and outputting a sampling signal;
and the driving circuit 320 is electrically connected with the voltage sampling circuit 310 and is used for outputting a driving signal when the second power supply signal VO2 is output to the second power supply output circuit according to the sampling signal, wherein the driving signal is used for driving the first power supply output circuit to turn off the output.
The output voltage of the second power input circuit 200 is sampled by the voltage sampling circuit 310 for detecting whether the second power output circuit outputs the second power signal VO2, and when the driving circuit 320 recognizes that the second power output circuit outputs the second power signal VO2 according to the sampling signal output by the voltage sampling circuit 310, the driving circuit 320 outputs a driving signal to drive the first power input circuit 100 to turn off the output. In one embodiment, a controlled switch may be disposed in the first power input circuit 100, the on/off of the first power input circuit 100 is controlled by controlling the on/off of the controlled switch, a controlled end of the controlled switch is electrically connected to the driving circuit 320, and the on/off of the controlled switch is controlled according to a driving signal output by the driving circuit 320.
Since the output voltage of the second power input circuit 200 may exceed the tolerable voltage range of the driving circuit 320, sampling by the voltage sampling circuit 310 can reduce the voltage signal input to the driving circuit 320, reduce the influence of voltage fluctuation, protect the driving circuit 320, and improve the identification accuracy of the driving circuit 320.
In one embodiment, as shown in fig. 4, the voltage sampling circuit 310 includes: a first resistor R1, a second resistor R2 and a third resistor R3; the driving circuit 320 includes: a first N-channel field effect transistor S1 and an optical coupler OC;
a first end of the first resistor R1 is electrically connected to the first power input circuit 100 as an input end of the switching detection circuit 300, and a second end is electrically connected to a first end of the second resistor R2;
a second end of the second resistor R2 is grounded;
a first end of the third resistor R3 is electrically connected with a first end of the first end circuit, and a second end of the third resistor R3 is electrically connected with an anode of a light emitting diode of the optocoupler OC;
the drain electrode of the first N-channel field effect transistor S1 is electrically connected with the cathode of a light emitting diode of the optocoupler OC, the grid electrode of the first N-channel field effect transistor S1 is electrically connected with the second end of the first resistor R1, and the source electrode of the first N-channel field effect transistor S1 is grounded;
the collector electrode of the phototriode of the optocoupler OC is used as a first potential NH + of the driving signal output end, and the emitter electrode of the phototriode of the optocoupler OC is used as a second potential NH-of the driving signal output end, and the phototriode of the optocoupler OC is used for outputting a driving signal to the controlled end of the first power input circuit 100 when being conducted.
An output signal of the second power input circuit 200 is divided by the first resistor R1 and the second resistor R2 and then a sampling signal is output to a grid electrode of the first N-channel field effect transistor S1, when the sampling signal reaches a starting voltage of the first N-channel field effect transistor S1, the first N-channel field effect transistor S1 is conducted, after an output signal of the second power input circuit 200 is limited by the third resistor R3, a path is formed through a light emitting diode of the optical coupler OC and the first N-channel field effect transistor S1, at this time, the optical coupler OC is conducted, a phototriode of the optical coupler OC is conducted, a driving signal output end is conducted to a controlled end of the first power input circuit 100, when the controlled end of the first power input circuit 100 receives a driving signal, the first power input circuit 100 is disconnected from output, and at this time, the second power input circuit 200 supplies power to the power consumption device 400.
In one embodiment, as shown in fig. 5, the first unidirectional output circuit 500 includes: the first current flows to the controller U1 and the second N-channel FET S2;
the first current flow controller U1 includes a power supply terminal VCC, a first voltage input terminal IN, a second voltage input terminal OUT, a control signal output terminal and a ground terminal GND, the power supply terminal VCC and the first voltage input terminal IN of the first current flow controller U1 are both electrically connected to the output terminal of the first power supply input circuit 100, the second voltage input terminal OUT of the first current flow controller U1 is electrically connected to the working power supply output terminal, and the ground terminal GND is grounded;
the source electrode of the second N-channel field effect transistor S2 is electrically connected with the output end of the first power input circuit 100, and the drain electrode is electrically connected with the output end of the working power supply; the gate is electrically connected to the control signal output of the first current flow controller U1.
The first current flow controller U1 is used for comparing the voltages at the output terminal of the first power input circuit 100 and the output terminal of the working power supply, and outputting a control signal to the gate of the second N-channel fet S2, so as to control the current flow and prevent the second power signal VO2 output by the second power input circuit 200 from flowing into the output terminal of the first power input circuit. When the output voltage of the first power input circuit 100 is higher than the voltage of the working power output terminal, the first current flow controller U1 outputs a high level signal to the gate of the second N-channel fet S2, and the second N-channel fet S2 is turned on, so that the first power signal VO1 output by the first power input circuit 100 can flow to the working power output terminal; when the output voltage of the first power input circuit 100 is lower than the voltage of the working power output terminal, the first current flow controller U1 outputs a low level signal to the gate of the second N-channel fet S2, and the second N-channel fet S2 is turned off, i.e., the path between the first power input circuit 100 and the working power output terminal is cut off, so as to prevent the second power signal VO2 output by the second power input circuit 200 from flowing backward to the first power supply through the first power input circuit 100. Compared with the traditional method of realizing one-way conduction by adopting a diode, the method can provide an OR gate channel with low on-resistance, reduce the heat loss of a power supply and be applied to a large-current load.
In one embodiment, the first current flow controller U1 may be a comparator, a comparison circuit, or a control chip with voltage comparison function.
In one embodiment, the first unidirectional output circuit 500 may also implement unidirectional conduction using a diode.
In one embodiment, the first unidirectional output circuit 500 further includes: a first capacitance C1;
the first terminal of the first capacitor C1 is electrically connected to the power terminal VCC of the first current flow controller U1, and the second terminal is grounded.
The first capacitor C1 is a filter capacitor, and is configured to filter the first power signal VO1 output by the first power input circuit 100, and then input the first power signal VO1 to a power supply terminal VCC of the first current flow controller U1.
In one embodiment, as shown in fig. 6, the second unidirectional output circuit 600 includes: the second current flows to the controller U2 and the third N-channel FET S3;
the second current flow controller U2 includes a power supply terminal VCC, a first voltage input terminal IN, a second voltage input terminal OUT, a control signal output terminal and a ground terminal GND, the power supply terminal VCC and the first voltage input terminal IN of the second current flow controller U2 are both electrically connected to the output terminal of the second power supply input circuit 200, the second voltage input terminal OUT of the second current flow controller U2 is electrically connected to the working power supply output terminal, and the ground terminal GND is grounded;
the source electrode of the third N-channel field effect transistor S3 is electrically connected to the output end of the second power input circuit 200, and the drain electrode is electrically connected to the output end of the working power supply; the gate is electrically connected to the control signal output of the second current flow controller U2.
The second current flow controller U2 is used for comparing the voltages at the output terminal of the second power input circuit 200 and the output terminal of the working power supply, and outputting a control signal to the gate of the third N-channel fet S3, so as to control the current flow and prevent the first power signal VO1 output by the first power input circuit 100 from flowing into the output terminal of the second power input circuit. When the output voltage of the second power input circuit 200 is higher than the voltage of the working power output terminal, the second current flow controller U2 outputs a high level signal to the gate of the third N-channel fet S3, and the third N-channel fet S3 is turned on, so that the second power signal VO2 output by the second power input circuit 200 can flow to the working power output terminal; when the output voltage of the second power input circuit 200 is lower than the voltage of the working power output terminal, the second current flow controller U2 outputs a low level signal to the gate of the third N-channel fet S3, and the third N-channel fet S3 is turned off, i.e., the path between the second power input circuit 200 and the working power output terminal is cut off, so as to prevent the first power signal VO1 output by the first power input circuit 100 from flowing backward to the second power supply through the second power input circuit 200. Compared with the traditional method of realizing one-way conduction by adopting a diode, the method can provide an OR gate channel with low on-resistance, reduce the heat loss of a power supply and be applied to a large-current load.
In one embodiment, the second unidirectional output circuit 600 may also realize unidirectional conduction through a diode.
In one embodiment, the second unidirectional output circuit 600 further includes: a second capacitance C2;
the first terminal of the second capacitor C2 is electrically connected to the power terminal VCC of the second current flow controller U2, and the second terminal is grounded.
The second capacitor C2 is a filter capacitor, and is configured to filter the second power signal VO2 output by the second power input circuit 200, and then input the second power signal VO2 to the power supply terminal VCC of the second current flow controller U2.
In one embodiment, the first power input circuit 100 and the second power input circuit 200 each include:
an input filter circuit for filtering the output signal of the first power supply/the second power supply;
and the DC/DC conversion circuit is used for carrying out isolation conversion on the voltage output by the input filter circuit and converting the voltage into a first power supply signal VO 1/a second power supply signal VO 2.
When the first power supply is a DC power supply, the first power input circuit 100 includes an input filter circuit and a DC/DC conversion circuit, and after the output signal of the first power supply is filtered by the input filter circuit, the filtered output signal is input to the DC/DC conversion circuit for isolation conversion, and is converted into a first power supply signal VO 1. In one embodiment, the DC/DC conversion circuit can boost or buck the output signal of the input filter circuit as required, in addition to implementing voltage isolation conversion.
When the second power supply is a DC power supply, the second power input circuit 200 includes an input filter circuit and a DC/DC conversion circuit, and after the output signal of the second power supply is filtered by the input filter circuit, the filtered output signal is input to the DC/DC conversion circuit for isolation conversion, and is converted into a second power supply signal VO 2. In one embodiment, the DC/DC conversion circuit can boost or buck the output signal of the input filter circuit as required, in addition to implementing voltage isolation conversion.
In one embodiment, when the first power source is an ac power source, the first power input circuit 100 includes an input filter circuit and a rectifier circuit, and the output signal of the first power source is filtered by the input filter circuit and then input to the rectifier circuit, so that the ac signal is rectified and then output as a dc signal to power the electric device 400.
In one embodiment, when the second power source is an ac power source, the second power input circuit 200 includes an input filter circuit and a rectifier circuit, and the output signal of the second power source is filtered by the input filter circuit and then input to the rectifier circuit, so that the ac signal is rectified and then output as a dc signal to power the electric device 400.
In one embodiment, the power switching circuit further includes:
and the output filter circuit is electrically connected to the first power input circuit 100 and the second power input circuit 200, and is configured to filter the first power signal VO1 or the second power signal VO2 and output the working power signal VO.
The output filter circuit is configured to filter the first power signal VO1 output by the first power input circuit 100 or the second power signal VO2 output by the second power input circuit 200, suppress interference, and output a low-noise operating power signal VO to the electric device 400.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. A power switching circuit, comprising:
the first power supply input circuit is used for being electrically connected with a first power supply, converting an output signal of the first power supply and outputting a first power supply signal;
the second power supply input circuit is used for being electrically connected with a second power supply and outputting a second power supply signal after converting an output signal of the second power supply, and the output end of the second power supply input circuit and the output end of the first power supply input circuit are both used for being electrically connected with the output end of a working power supply;
and the switching detection circuit is electrically connected with the output end of the second power input circuit and the control end of the first power input circuit and is used for outputting a switching control signal to drive the first power input circuit to switch off and output when detecting that the second power input circuit outputs the second power signal, so that the first power signal is output to the working power output end and is switched to the second power signal to be output to the working power output end.
2. The power switching circuit of claim 1, further comprising:
the input end of the first unidirectional output circuit is electrically connected with the output end of the first power supply input circuit, and the output end of the first unidirectional output circuit is electrically connected with the output end of the working power supply and is used for preventing a second power supply signal from flowing backwards to the first power supply;
and the input end of the second unidirectional output circuit is electrically connected with the output end of the second power supply input circuit, and the output end of the second unidirectional output circuit is electrically connected with the output end of the working power supply and is used for preventing the first power supply signal from flowing backwards to the second power supply.
3. The power switching circuit of claim 1, wherein the switching detection circuit comprises:
the voltage sampling circuit is used for sampling the output voltage of the second power output circuit and outputting a sampling signal;
and the driving circuit is electrically connected with the voltage sampling circuit and used for outputting a driving signal when the second power supply signal is output to the second power supply output circuit according to the sampling signal, and the driving signal is used for driving the first power supply output circuit to be switched off and output.
4. The power switching circuit of claim 3, wherein the voltage sampling circuit comprises: a first resistor, a second resistor and a third resistor; the drive circuit includes: a first N-channel field effect transistor and an optical coupler;
a first end of the first resistor is used as an input end of the switching detection circuit and is electrically connected with the first power input circuit, and a second end of the first resistor is electrically connected with a first end of the second resistor;
the second end of the second resistor is grounded;
the first end of the third resistor is electrically connected with the first end of the first end circuit, and the second end of the third resistor is electrically connected with the anode of a light emitting diode of the optocoupler;
the drain electrode of the first N-channel field effect transistor is electrically connected with the cathode of the light emitting diode of the optocoupler, the grid electrode of the first N-channel field effect transistor is electrically connected with the second end of the first resistor, and the source electrode of the first N-channel field effect transistor is grounded;
and the collector electrode of the phototriode of the optocoupler is used as a first potential of the driving signal output end, and the emitter electrode of the phototriode of the optocoupler is used as a second potential of the driving signal output end and is used for outputting the driving signal to the controlled end of the first power input circuit when the phototriode of the optocoupler is switched on.
5. The power switching circuit of claim 2, wherein the first unidirectional output circuit comprises: the first current flows to the controller and the second N-channel field effect transistor;
the first current flow direction controller comprises a power supply end, a first voltage input end, a second voltage input end, a control signal output end and a grounding end, wherein the power supply end and the first voltage input end of the first current flow direction controller are electrically connected with the output end of the first power supply input circuit, the second voltage input end of the first current flow direction controller is electrically connected with the output end of the working power supply, and the grounding end is grounded;
the source electrode of the second N-channel field effect transistor is electrically connected with the output end of the first power supply input circuit, and the drain electrode of the second N-channel field effect transistor is electrically connected with the output end of the working power supply; the grid is electrically connected with the control signal output end of the first current flow controller.
6. The power switching circuit of claim 5, wherein the first unidirectional output circuit further comprises: a first capacitor;
the first end of the first capacitor is electrically connected with a power supply end of the first current flowing to the controller, and the second end of the first capacitor is grounded.
7. The power switching circuit of claim 5, wherein the second unidirectional output circuit comprises: the second current flows to the controller and the third N-channel field effect transistor;
the second current flow direction controller comprises a power supply end, a first voltage input end, a second voltage input end, a control signal output end and a grounding end, wherein the power supply end and the first voltage input end of the second current flow direction controller are electrically connected with the output end of the second power supply input circuit, the second voltage input end of the second current flow direction controller is electrically connected with the output end of the working power supply, and the grounding end is grounded;
the source electrode of the third N-channel field effect transistor is electrically connected with the output end of the second power supply input circuit, and the drain electrode of the third N-channel field effect transistor is electrically connected with the output end of the working power supply; the grid is electrically connected with the control signal output end of the second current flow controller.
8. The power switching circuit of claim 7, wherein the second unidirectional output circuit further comprises: a second capacitor;
and the first end of the second capacitor is electrically connected with the power supply end of the second current flowing to the controller, and the second end of the second capacitor is grounded.
9. The power supply switching circuit according to claim 1, wherein the first power supply input circuit and the second power supply input circuit each comprise:
an input filter circuit for filtering output signals of the first power supply/the second power supply;
and the DC/DC conversion circuit is used for carrying out isolation conversion on the voltage output by the input filter circuit and converting the voltage into the first power supply signal/the second power supply signal.
10. The power switching circuit of claim 1, further comprising:
and the output filter circuit is electrically connected with the first power supply input circuit and the second power supply input circuit and is used for outputting a working power supply signal after filtering the first power supply signal or the second power supply signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020288688.9U CN211958854U (en) | 2020-03-10 | 2020-03-10 | Power supply switching circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020288688.9U CN211958854U (en) | 2020-03-10 | 2020-03-10 | Power supply switching circuit |
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| CN211958854U true CN211958854U (en) | 2020-11-17 |
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