Backup circuit with zero current switching and backup method thereof

Abstract

A backup circuit with zero current switching and a backup method thereof are provided, providing multiple input source backup loads, and the backup circuit includes: a first switch, a second switch and a control unit. The input source includes at least a first input source and a second input source; when the power supply source of the load is to be switched from the first input source to the second input source, the control unit controls the power supply current on the first power supply path and the second power supply path coupled to the first input source and the load to be reduced to less than a threshold, controls the first switch to switch to couple to the second input source, and controls the second switch to switch to couple to the second input source.

Description

Technical Field

[0001] The present invention relates to a backup circuit with zero current switching and a backup method thereof, and more particularly to a backup circuit and a backup method thereof for reducing the current passing through the backup circuit before switching. Background Art

[0002] As data centers are increasingly used, and as they must maintain stable operation and improve reliability, backup circuits are often used at the front end of today’s data centers to maintain continuous operation. Currently, backup circuits have been widely used in various data centers and servo power input stages to improve power supply reliability and flexibility.

[0003] In recent years, due to the requirements of system space and equipment capacity utilization, backup circuits have gradually been integrated from individual units of the system into power units. However, the current backup systems are not only large in size and high in cost, but also do not have a design that meets high power density in power supply design.

[0004] Therefore, how to design a backup circuit with zero current switching and a backup method thereof, and use the backup circuit to reduce the current flowing through the backup circuit before switching to improve power density and working efficiency, is a major issue that the inventors of the present disclosure want to overcome and solve. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a backup circuit with zero current switching to overcome the problems of the prior art. Therefore, the backup circuit of the present invention provides multiple input source backup loads, and the backup circuit includes: a first switch, including multiple first ends and second ends, the first end is correspondingly coupled to one end of the input source, the second end is coupled to one end of the load, and the path from the first end to the second end that is turned on is the first power supply path. A second switch, including multiple third ends and fourth ends, the third end is correspondingly coupled to the other end of the input source, the fourth end is coupled to the other end of the load, and the path from the third end to the fourth end that is turned on is the second power supply path. And a control unit, coupled to the first switch and the second switch. Among them, the input source includes at least a first input source and a second input source; when the power supply source of the load is to be switched from the first input source to the second input source, the control unit controls the power supply current on the first power supply path and the second power supply path to be reduced to less than a threshold, and then controls the second end of the first switch to switch to couple to the first end corresponding to the second input source, and controls the fourth end of the second switch to switch to couple to the third end corresponding to the second input source.

[0006] In order to solve the above problems, the present invention provides a backup method of a backup circuit with zero current switching to overcome the problems of the prior art. Therefore, the backup method of the backup circuit of the present invention provides multiple input power backup loads, and the input source includes at least a first input source and a second input source. The backup method includes the following steps: controlling one of the multiple first ends of the first switch to couple to one end of the first input source, so that the first end to the second end of the first switch constitutes a first power supply path for powering one end of the load. Controlling one of the multiple third ends of the second switch to couple to the other end of the first input source, so that the third end to the fourth end of the second switch constitutes a second power supply path for powering the other end of the load. When the input power is to be switched from the first input source to the second input source, the supply current on the first power supply path and the second power supply path is controlled to be reduced to less than a threshold. Controlling the first switch to switch to couple to the first end corresponding to the second input source. And controlling the second switch to switch to couple to the third end corresponding to the second input source.

[0007] In summary, the main purpose and technical effect of the present invention is to utilize the backup circuit to reduce the current flowing through the backup circuit before switching, so as to achieve the technical effect of improving power density and working efficiency.

[0008] In order to further understand the technology, means and technical effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, characteristics and features of the present invention can be deeply and specifically understood thereby. However, the drawings in the specification are only provided for reference and explanation and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a circuit block diagram of a first embodiment of a backup circuit with zero current switching according to the present invention;

[0010] Figure 2A The first embodiment of the backup circuit with zero current switching of the present invention is a waveform diagram in which the first switch and the second switch are magnetic latching relays;

[0011] Figure 2B A waveform diagram of the first embodiment of the backup circuit with zero current switching of the present invention, in which the first switch and the second switch are not magnetic latching relays;

[0012] Figure 3 is a circuit block diagram of a second embodiment of a backup circuit with zero current switching according to the present invention;

[0013] Figure 4A A waveform diagram of a second embodiment of a backup circuit with zero current switching according to the present invention, in which the first switch and the second switch are magnetic latching relays;

[0014] Figure 4B A waveform diagram of a second embodiment of a backup circuit with zero current switching according to the present invention, in which the first switch and the second switch are non-magnetic latching relays; and

[0015] Figure 5 FIG. 4 is a circuit block diagram of a third embodiment of a backup circuit with zero current switching according to the present invention.

[0016] Description of reference numerals:

[0017] 100, 100', 100" ... backup circuit

[0018] A~D…end

[0019] 12, 12'…First switch

[0020] 122…First End

[0021] 124…Second end

[0022] 13…Switch module

[0023] 132…Control coil

[0024] 14, 14'…Second switch

[0025] 142…The third end

[0026] 144…The fourth end

[0027] 16…Control unit

[0028] 22…First bypass unit

[0029] 222…First bypass switch

[0030] 224…First current limiting unit

[0031] SCR1…First silicon controlled rectifier unit

[0032] SCR2…Second silicon controlled rectifier unit

[0033] 24…Second bypass unit

[0034] 242…Second bypass switch

[0035] 244…Second current limiting unit

[0036] SCR3…The third silicon controlled rectifier unit

[0037] SCR4…the fourth silicon controlled rectifier unit

[0038] X…Anode

[0039] Y…Cathode

[0040] Z…Control terminal

[0041] 32, 34…Current detector

[0042] 200…Load

[0043] Vin1~Vin2…input source

[0044] I1, I2…input current

[0045] Sc11, Sc12... first control signal

[0046] Sc21, Sc22...second control signal

[0047] Si1, Si2…current signal

[0048] P1…First power supply path

[0049] P2…Second power supply path

[0050] t1~t7…time

[0051] Rp…predetermined range

[0052] Tr1…First switching period

[0053] Tr2…Second switching period DETAILED DESCRIPTION

[0054] The technical content and detailed description of the present invention are described as follows with reference to the accompanying drawings:

[0055] See also Figure 1 The first embodiment of the backup circuit with zero current switching of the present invention is a circuit block diagram. The backup circuit 100 is coupled between a plurality of input sources Vin1-Vin2 and a load 200, and is used to provide a plurality of input sources Vin1-Vin2 with backup for the load 200. When the input source Vin1-Vin2 (assuming the input source Vin1) coupled to the load 200 is abnormal, the backup circuit 100 switches to couple to another input source Vin1-Vin2 (assuming the input source Vin2) to provide a backup function for the input sources Vin1-Vin2. In one embodiment of the present invention, the input sources Vin1-Vin2 are AC power sources, and provide AC power to power the load 200. The redundancy circuit 100 includes a first switch 12 , a second switch 14 and a control unit 16 . The control unit 16 is coupled to the first switch 12 and the second switch 14 to provide first control signals Sc11 and Sc12 to control switching of the first switch 12 and to provide second control signals Sc21 and Sc22 to control switching of the second switch 14 .

[0056] The first switch 12 includes a plurality of first terminals 122 and a second terminal 124, wherein the first terminals 122 are respectively coupled to terminals A of the input sources Vin1-Vin2 (i.e., the live terminals of the input sources Vin1-Vin2), and the second terminal 124 of the first switch 12 is coupled to terminal B of the load 200 (i.e., the live terminal of the load 200). The path from the first terminal 122 to the second terminal 124 that is turned on is a first power supply path P1 (the present embodiment is illustrated by the input source Vin1 coupled to the load 200). The second switch 14 includes a plurality of third terminals 142 and a fourth terminal 144, wherein the third terminals 142 are respectively coupled to the other terminals C of the input sources Vin1-Vin2 (i.e., the neutral terminals of the input sources Vin1-Vin2), and the fourth terminal 144 of the second switch 14 is coupled to the other terminal D of the load 200 (i.e., the neutral terminal of the load 200). The path from the third end 142 to the fourth end 144 that is turned on is the second power supply path P2. The input source Vin1 can form a loop through the first power supply path P1 and the second power supply path P2 to supply power to the load 200. Therefore, at a single time point, only a single input source Vin1-Vin2 is coupled to the load 200 to supply power to the load 200, and the other uncoupled input sources Vin1-Vin2 provide a backup function.

[0057] The backup circuit 100 further includes a first bypass unit 22 and a second bypass unit 24, wherein the first bypass unit 22 is coupled between the first switch 12 and the load 200, and the second bypass unit 24 is coupled between the second switch 14 and the load 200. Specifically, the first bypass unit 22 includes a first bypass switch 222 and a first current limiting unit 224, and the second bypass unit 24 includes a second bypass switch 242 and a second current limiting unit 244. The first bypass switch 222 is coupled between the second end 124 of the first switch 12 and one end B of the load 200, and the first current limiting unit 224 is connected in parallel with the first bypass switch 222. The second bypass switch 242 is coupled between the fourth end 144 of the second switch 14 and the other end D of the load 200, and the second current limiting unit 244 is connected in parallel with the second bypass switch 242.

[0058] The first current limiting unit 224 includes a first silicon-controlled rectifier unit SCR1 and a second silicon-controlled rectifier unit SCR2, and the second current limiting unit 244 includes a third silicon-controlled rectifier unit SCR3 and a fourth silicon-controlled rectifier unit SCR4. The first silicon-controlled rectifier unit SCR1 includes an anode X, a cathode Y, and a control terminal Z, wherein the anode X is coupled to the second terminal 124 of the first switch 12, and the cathode Y is coupled to a terminal B of the load 200. The second silicon-controlled rectifier unit SCR2 includes an anode X, a cathode Y, and a control terminal Z, wherein the anode X is coupled to the cathode Y of the first silicon-controlled rectifier unit SCR1, and the cathode Y is coupled to the anode X of the first silicon-controlled rectifier unit SCR1. The control terminals Z of the first silicon-controlled rectifier unit SCR1 and the second silicon-controlled rectifier unit SCR2 are used to control the currents that can flow through the first silicon-controlled rectifier unit SCR1 and the second silicon-controlled rectifier unit SCR2, respectively, to achieve a current limiting effect. Among them, since the first silicon-controlled rectifier unit SCR1 and the second silicon-controlled rectifier unit SCR2 control the current that can flow through by the voltage of the control terminal Z, the coupling position of the control terminal Z is not limited. For example but not limited to, the control terminal Z can be coupled to the input source Vin1~Vin2, the control unit 16 or the external power supply to receive a voltage suitable for limiting the current. The coupling relationship and control method of the third silicon-controlled rectifier unit SCR3 and the fourth silicon-controlled rectifier unit SCR4 are similar to those of the first silicon-controlled rectifier unit SCR1 and the second silicon-controlled rectifier unit SCR2, and will not be repeated here.

[0059] Specifically, at the moment when the first switch 12 and the second switch 14 generate the first power supply path P1 and the second power supply path P2, since the working voltage of the load 200 may not be established or the working voltage of 200 may not be stable, a surge current with a current value that is too large instantly is easily generated at this time. This surge current may accelerate the aging of the first switch 12 and the second switch 14, or cause damage to the load 200. Therefore, at the moment when the first switch 12 and the second switch 14 generate the first power supply path P1 and the second power supply path P2, the first current limiting unit 224 and the second current limiting unit 244 are used to limit the current on the first power supply path P1 and the second power supply path P2 to avoid damage to the first switch 12, the second switch 14 or the load 200. Moreover, after there is no surge current, the first bypass switch 222 and the second bypass switch 242 are turned on to bypass the first current limiting unit 224 and the second current limiting unit 244, thereby avoiding the first current limiting unit 224 and the second current limiting unit 244 from continuously consuming power to save the power consumption of the backup circuit 100.

[0060] See also Figure 1The backup circuit 100 further includes current detectors 32 and 34. The current detectors 32 and 34 preferably use misplaced current detectors. That is, the current detector 32 is coupled to the live wire end of the input source Vin1 and the current detector 34 is coupled to the neutral wire end of the input source Vin2 (or the current detector 32 is coupled to the neutral wire end of the input source Vin1 and the current detector 34 is coupled to the live wire end of the input source Vin2), and provides current signals Si1 and Si2 to the control unit 16 according to the detected input currents I1 and I2, respectively, so that the control unit 16 can judge whether the switching action when the first switch 12 and the second switch 14 are switched is correct (i.e., it is normally executed) according to the current signals Si1 and Si2. Specifically, the control unit 16 uses the current detectors 32 and 34 to provide an error detection mechanism when the first switch 12 and the second switch 14 are switched. It determines whether the switch relationship is normally operated by detecting the current before and after each switching of the first switch 12 and the second switch 14, thereby avoiding the risk of damage to the backup circuit 100 or the load 200 due to erroneous switching action or switch damage. The current detectors 32 and 34 can also be used to detect the circuit structure in which the backup circuit 100 is a dual input source with the same source or a common neutral point.

[0061] See also Figure 2A The first embodiment of the backup circuit with zero current switching of the present invention is shown in FIG. 1 , and the first switch 12 and the second switch 14 are waveform diagrams of magnetic latching relays. Figure 1 The characteristic of the magnetic latching relay is that it can complete the switch conversion only by being triggered by a pulse signal of a certain width. For example, after the magnetic latching relay receives a high-level control signal to turn it on, the relay can be continuously adsorbed by the magnetic force. At this time, the control signal can be switched to a low level, and the relay can be kept on without continuously providing a high-level control signal. Therefore, its control signal forms a pulse. Therefore, the technical effect of saving the power consumption of the backup circuit 100 can be achieved.

[0062] See also Figure 2A When the control unit 16 detects that there are input sources Vin1-Vin2, and the control unit 16 intends to control the first switch 12 and the second switch 14 to conduct the input source Vin1 to couple the load 200, the control unit 16 provides a high-level first control signal Sc11 to the first switch 12 to couple the first terminal 122 corresponding to one terminal A of the input source Vin1 to the second terminal 124, so as to generate a first power supply path P1 belonging to the input source Vin1 (time t1). At the same time, the control unit 16 also provides a high-level second control signal Sc21 to the second switch 14 to couple the third terminal 142 corresponding to the other terminal C of the input source Vin1 to the fourth terminal 144, so as to generate a second power supply path P2 belonging to the input source Vin1 (time t1).

[0063] When the first switch 12 establishes the first power supply path P1 belonging to the input source Vin1 and the second switch 14 establishes the second power supply path P2 belonging to the input source Vin1, the first switch 12 and the second switch 14 can use magnetic force to respectively attract the first end 122 and the third end 142, so the first control signal Sc11 and the second control signal Sc21 are converted to a low level (time t2). At this time, the first current limiting unit 224 is turned on to limit the current flowing through the first power supply path P1 (time t2), and the second current limiting unit 244 is also turned on at the same time to limit the current flowing through the second power supply path P2 (time t2). After there is no surge current, the first bypass switch 222 and the second bypass switch 242 are turned on (time t3) to bypass the first current limiting unit 224 and the second current limiting unit 244 to prevent the first current limiting unit 224 and the second current limiting unit 244 from continuously consuming power.

[0064] When the control unit 16 detects that the input source Vin1 is powered off or the voltage value of the input source Vin1 is lower than the predetermined range Rp (indicated by the dotted line), or when the input power switching is required due to power allocation or scheduling (time t4), a backup circuit shutdown sequence is provided. The control unit 16 first controls the power supply current on the first power supply path P1 and the second power supply path P2 to be reduced to less than the threshold value, which is mainly based on the current when the load 200 is unloaded as the threshold setting, and the current value is mainly substantially equal to 0 as the preferred threshold value. Among them, the control unit 16 may include a variety of ways to reduce the power supply current to less than or equal to the threshold. For example, but not limited to, providing a signal to the load 200 so that the load 200 will reduce its own load to no load, or using an additional current limiting unit to limit the size of the power supply current.

[0065] Then, when the power supply current on the first power supply path P1 and the second power supply path P2 is reduced to less than the threshold value, the control unit 16 controls the first power supply path P1 and the second power supply path P2 to be disconnected (time t5). That is, the control unit 16 controls the first switch 12 to switch from the first end 122 coupled to the input source Vin1 to the first end 122 coupled to the input source Vin2, and the first power supply path P1 of the input source Vin1 coupled to the load 200 is turned off (the second switch 14 is the same). Since the current values ​​of the first power supply path P1 and the second power supply path P2 are very small (even 0), compared with the existing switching under the load 200, the switching process will not be subject to too much current stress, and no arc will be generated during the switching, so that the backup circuit 100 of the present invention can achieve the technical effect of safe backup under low current. Then, when the first power supply path P1 and the second power supply path P2 coupled to the input source Vin1 are turned off, the first current limiting unit 224 and the first bypass switch 222 are turned off at the same time (time t5), and the second current limiting unit 244 and the second bypass switch 242 are also turned off at the same time (time t5). Therefore, the load 200 can completely cut off the coupling relationship of the input source Vin1.

[0066] The control unit 16 controls the first power supply path P1 and the second power supply path P2 belonging to the input source Vin1 to be disconnected (time t5), and the control unit 16 also provides a backup circuit conduction sequence. The control unit 16 provides a high-level first control signal Sc12 to the first switch 12, so that the second end 124 of the first switch 12 switches from being coupled to the first end 122 of the corresponding input source Vin1 to being coupled to the first end 122 of the corresponding input source Vin2 (time t5), so as to establish the first power supply path P1 from the input source Vin2 to the load 200. The control unit 16 also simultaneously provides a high-level second control signal Sc22 to the second switch 14, so that the fourth end 144 of the second switch 14 switches from being coupled to the third end 142 of the corresponding input source Vin1 to being coupled to the third end 142 of the corresponding input source Vin2 (time t5), so as to establish the second power supply path P2 from the input source Vin2 to the load 200.

[0067] When the first switch 12 establishes the first power supply path P1 belonging to the input source Vin2 and the second switch 14 establishes the second power supply path P2 belonging to the input source Vin2, the first switch 12 and the second switch 14 can use magnetic force to attract the first end 122 and the third end 142, so the first control signal Sc12 and the second control signal Sc22 are converted to a low level (time t6). At this time, the first current limiting unit 224 is turned on to limit the current flowing through the first power supply path P1 (time t6), and the second current limiting unit 244 is also turned on at the same time to limit the current flowing through the second power supply path P2 (time t6). After there is no surge current, the first bypass switch 222 and the second bypass switch 242 are turned on (time t7) to bypass the first current limiting unit 224 and the second current limiting unit 244 to prevent the first current limiting unit 224 and the second current limiting unit 244 from continuously consuming power. Finally, when the first bypass switch 222 is turned on and the second bypass switch 242 is turned on, the control unit 16 releases the restriction that the supply current is less than the threshold, so that the load 20 starts to draw load.

[0068] The control unit 16 controls the first switch 12 to turn off the first end 122 of the corresponding input source Vin1 and couple it to the second end 124 (time t5) and couple it to the first end 122 of the corresponding input source Vin2 (time t6), and the control unit 16 controls the second switch 14 to turn off the third end 142 of the corresponding input source Vin1 and couple it to the fourth end 144 (time t5) and couple it to the third end 142 of the corresponding input source Vin2 (time t6), and the second switch 14 is controlled by the control unit 16. The period is the second switching period Tr2. Since the switching of the first switch 12 and the second switch 14 is performed when the power supply current is reduced to less than the threshold, the power supply current is extremely small, so that the first switch 12 and the second switch 14 can switch without burden. Therefore, the first switch 12 and the second switch 14 can simultaneously remove the input source Vin1 and connect the input source Vin2, so that the first switching period Tr1 and the second switching period Tr2 can be limited to approximately equal to the mechanical delay time of the switch switching. It is worth mentioning that in one embodiment of the present invention, the high level and the low level of the control signal can be interchanged, that is, the control of the high level and the low level is just opposite.

[0069] See also Figure 2B The first embodiment of the backup circuit with zero current switching of the present invention is a waveform diagram of the first switch and the second switch which are not magnetic latching relays. Figures 1 to 2A. Since the first switch 12 and the second switch 14 are not magnetic latching relays, the control unit 16 must continuously provide a high-level first control signal Sc11 to turn on the first power supply path P1 belonging to the input source Vin1, and continuously provide a high-level second control signal Sc21 to turn on the second power supply path P2 belonging to the input source Vin1. When the control unit 16 detects that the input source Vin1 is powered off or the voltage value of the input source Vin1 is lower than the predetermined range Rp (indicated by a dotted line), or when the input power switching is required due to power allocation or scheduling (time t4), the control unit 16 first controls the power supply current on the first power supply path P1 and the second power supply path P2 to be less than the threshold. Then, the control unit 16 converts the first control signal Sc11 and the second control signal Sc21 to a low level, and simultaneously converts the first control signal Sc12 and the second control signal Sc22 to a high level (time t5) to turn on the first power supply path P1 and the second power supply path P2 belonging to the input source Vin2. It is worth mentioning that regarding Figure 2B All control methods not mentioned are related to Figure 2A The same is not repeated here.

[0070] See also Figure 3 FIG. 1 is a circuit block diagram of a second embodiment of a backup circuit with zero current switching according to the present invention, and is also referred to in conjunction with FIG. Figures 1 to 2B . Figure 3 The backup circuit 100' and Figure 1 The difference between the backup circuit 100 and the backup circuit 100 is that the backup circuit 100' does not include the first bypass unit 22 and the second bypass unit 24. The second end 124 of the first switch 12 is directly coupled to one end B of the load 200, and the fourth end 144 of the second switch 14 is directly coupled to the other end D of the load 200. Specifically, since the input end of the current electronic device or conversion circuit usually includes a current limiting circuit for suppressing surge current, in order to avoid wasting power by repeatedly using the circuit with the same technical effect to perform the same control, the backup circuit 100' omits the first bypass unit 22 and the second bypass unit 24. Figure 1 The first bypass unit 22 and the second bypass unit 24 are shown to achieve the technical effect of further saving the power consumption of the backup circuit 100' and further improving the efficiency of the backup circuit 100'. It is worth mentioning that in one embodiment of the present invention, Figure 3 The components and coupling relationships not mentioned in Figure 1 , I will not elaborate on it here.

[0071] See also Figure 4A FIG. 1 is a waveform diagram of a second embodiment of a backup circuit with zero current switching according to the present invention, wherein the first switch and the second switch are magnetic latching relays. Figures 1 to 3 .like Figure 4AAs shown, since the backup circuit 100' does not have the first bypass unit 22 and the second bypass unit 24, when the first switch 12 establishes the first power supply path P1 belonging to the input source Vin1 and the second switch 14 establishes the second power supply path P2 belonging to the input source Vin1, the first control signal Sc11 and the second control signal Sc21 are converted to a low level (time t2). When the first control signal Sc11 and the second control signal Sc21 are converted to a low level (time t2), the input source Vin1 supplies power to the load 200 through the first power supply path P1 and the second power supply path P2, and the current flowing through the first power supply path P1 and the second power supply path P2 is not limited after time t2. At this time, whether the current flowing through the first power supply path P1 and the second power supply path P2 is limited is determined by the load 200.

[0072] When the control unit 16 detects that the input source Vin1 is powered off or the voltage value of the input source Vin1 is lower than the predetermined range Rp (indicated by a dotted line), or switching is required due to power allocation or scheduling (time t3), the control unit 16 controls the power supply current on the first power supply path P1 and the second power supply path P2 to be reduced to less than the threshold value, and when the power supply current on the first power supply path P1 and the second power supply path P2 is reduced to less than the threshold value, the control unit 16 controls the first power supply path P1 and the second power supply path P2 to be disconnected (time t4).

[0073] When the control unit 16 controls the first power supply path P1 and the second power supply path P2 to be disconnected (time t4), the control unit 16 provides a high-level first control signal Sc12 to the first switch 12, so that the second end 124 of the first switch 12 switches from the first end 122 coupled to the corresponding input source Vin1 to the first end 122 coupled to the corresponding input source Vin2 (time t4), so as to establish the first power supply path P1 from the input source Vin2 to the load 200. The control unit 16 also simultaneously provides a high-level second control signal Sc22 to the second switch 14, so that the fourth end 144 of the second switch 14 switches from the third end 142 coupled to the corresponding input source Vin1 to the third end 142 coupled to the corresponding input source Vin2 (time t4), so as to establish the second power supply path P2 from the input source Vin2 to the load 200.

[0074] When the first switch 12 establishes the first power supply path P1 belonging to the input source Vin2 and the second switch 14 establishes the second power supply path P2 belonging to the input source Vin2, the first switch 12 and the second switch 14 can use magnetic force to attract the first end 122 and the third end 142, so the first control signal Sc12 and the second control signal Sc22 are converted to a low level (time t5). Finally, when the first switch 12 switches to couple the first end 122 corresponding to the input source Vin2, and the second switch 14 switches to couple the third end 142 corresponding to the input source Vin2, the control unit 16 releases the restriction that the power supply current is less than the threshold value, so that the load 20 starts to draw the load. After the first control signal Sc12 and the second control signal Sc22 are converted to a high level (time t4) and after the mechanical delay time (time t5), the input source Vin2 supplies power to the load 200 through the first power supply path P1 and the second power supply path P2, and the current flowing through the first power supply path P1 and the second power supply path P2 is not limited after time t5. At this time, whether the current flowing through the first power supply path P1 and the second power supply path P2 is limited is determined by the load 200 .

[0075] See also Figure 4B FIG. 1 is a waveform diagram of a second embodiment of a backup circuit with zero current switching according to the present invention, wherein the first switch and the second switch are non-magnetic latching relays. Figures 1 to 4A Since the first switch 12 and the second switch 14 are not magnetic latching relays, the control unit 16 must continuously provide a high-level first control signal Sc11 to turn on the first power supply path P1 belonging to the input source Vin1, and continuously provide a high-level second control signal Sc21 to turn on the second power supply path P2 belonging to the input source Vin1. Figure 4B All control methods not mentioned are related to Figure 4A The same is not repeated here.

[0076] See also Figure 5 FIG. 1 is a circuit block diagram of a third embodiment of a backup circuit with zero current switching according to the present invention, and is also referred to in conjunction with FIG. Figures 1 to 4B . Figure 5 The backup circuit 100" and Figure 1The difference between the backup circuit 100 and the backup circuit 100 is that the first switch 12' and the second switch 14' in the backup circuit 100" are integrated into a single switch module 13, the first switch 12' includes a plurality of second ends 124 corresponding to the number of the first ends 122, and the second switch 14' includes a plurality of fourth ends 144 corresponding to the number of the third ends 142. The switch module 13 also includes a control coil 132, and the control coil 132 is a center-tapped coil, and can also be a single coil. When the control coil 132 is excited, the first switch 12' will only have a single first end 122 corresponding to the second end 124 coupled (the second switch 14' is also the same). It is worth mentioning that in one embodiment of the present invention, Figure 5 The components and coupling relationships not mentioned in Figure 1 , and the control method is the same as Figure 2A or Figure 2B The same is not repeated here.

[0077] However, the above description is only a detailed description and drawings of the preferred specific embodiments of the present invention, and the features of the present invention are not limited thereto and are not intended to limit the present invention. The entire scope of the present invention shall be based on the following claims. All embodiments that are consistent with the concepts of the claims of the present invention and similar variations thereof shall be included in the scope of the present invention. Any changes or modifications that can be easily conceived by any person skilled in the art within the field of the present invention shall be covered by the following claims of the present disclosure.

Claims

1. A backup circuit with zero current switching, providing multiple input sources to backup a load, and the backup circuit comprises: a first switch, comprising a plurality of first ends and a second end, wherein the plurality of first ends are coupled to one end of the plurality of input sources respectively, the second end is coupled to one end of the load, and the path from the first end to the second end that is turned on is a first power supply path; a second switch, comprising a plurality of third terminals and a fourth terminal, wherein the plurality of third terminals are correspondingly coupled to the other terminals of the plurality of input sources, the fourth terminal is coupled to the other terminal of the load, and a path from the third terminal to the fourth terminal that is turned on is a second power supply path; a control unit, coupled to the first switch and the second switch; and A plurality of current detectors are respectively coupled to the plurality of input sources and the control unit; Wherein, the multiple input sources include at least a first input source and a second input source; when the power supply source of the load is to be switched from the first input source to the second input source, the control unit controls a power supply current on the first power supply path and the second power supply path to be reduced to less than a threshold value, controls the second end of the first switch to switch and couple to the first end corresponding to the second input source, and controls the fourth end of the second switch to switch and couple to the third end corresponding to the second input source, Wherein, the current detector provides a first current signal corresponding to a live wire end of the first input source and a second current signal corresponding to a neutral wire end of the second input source; or, the current detector provides the first current signal corresponding to a neutral wire end of the first input source and the second current signal corresponding to a live wire end of the second input source, and the control unit determines whether the first switch and the second switch are working normally by switching the first current signal and the second current signal before and after switching the first switch and the second switch.

2. The backup circuit as claimed in claim 1, wherein after the second end of the first switch is switched to couple to the first end corresponding to the second input source, and the fourth end of the second switch is switched to couple to the third end corresponding to the second input source, the control unit releases the restriction that the power supply current is less than the threshold.

3. The backup circuit as claimed in claim 1, further comprising: A first bypass unit, comprising: a first bypass switch, coupling the second end of the first switch and one end of the load; a first current limiting unit connected in parallel with the first bypass switch; and A second bypass unit, comprising: a second bypass switch, coupling the fourth terminal of the second switch and the other terminal of the load; and A second current limiting unit is connected in parallel with the second bypass switch.

4. The backup circuit as described in claim 3, wherein the backup circuit conduction sequence of the first switch, the first bypass switch and the first current limiting unit switching from the first input source to the second input source is as follows: the second end of the first switch is switched to couple the first end corresponding to the second input source, the first current limiting unit is turned on and the first bypass switch is turned on; the backup circuit conduction sequence of the second switch, the second bypass switch and the second current limiting unit is as follows: the fourth end of the second switch is switched to couple the third end corresponding to the second input source, the second current limiting unit is turned on and the second bypass switch is turned on. 5 . The backup circuit as claimed in claim 4 , wherein when the first bypass switch is turned on and the second bypass switch is turned on, the control unit releases the restriction that the supply current is less than the threshold.

6. The backup circuit as described in claim 3, wherein when the power supply source of the load is to be switched from the first input source to the second input source, a shutdown sequence of the backup circuit of the first switch, the first bypass switch and the first current limiting unit is as follows: the first power supply path is disconnected, and the first current limiting unit and the first bypass switch are turned off simultaneously; and a shutdown sequence of the backup circuit of the second switch, the second bypass switch and the second current limiting unit is as follows: the second power supply path is disconnected, and the second current limiting unit and the second bypass switch are turned off simultaneously.

7. The redundancy circuit as claimed in claim 3, wherein the first current limiting unit comprises: A first silicon-controlled rectifier unit includes an anode and a cathode, wherein the anode is coupled to the second end, and the cathode is coupled to one end of the load; A second silicon-controlled rectifier unit includes an anode and a cathode, wherein the anode is coupled to the cathode of the first silicon-controlled rectifier unit, and the cathode is coupled to the anode of the first silicon-controlled rectifier unit; and The second current limiting unit comprises: a third silicon-controlled rectifier unit, comprising an anode and a cathode, the anode being coupled to the fourth terminal, and the cathode being coupled to the other terminal of the load; and A fourth silicon-controlled rectifier unit includes an anode and a cathode. The anode is coupled to the cathode of the third silicon-controlled rectifier unit, and the cathode is coupled to the anode of the third silicon-controlled rectifier unit.

8. The backup circuit as described in claim 1, wherein the first switch and the second switch are a magnetic holding relay, the control unit provides a first control signal to control the first switch to switch the coupling corresponding to the first end of the second input source, and provides a second control signal to control the second switch to switch the coupling corresponding to the third end of the second input source; the first control signal and the second control signal are a pulse.

9. The backup circuit as described in claim 1, wherein the control unit controls the first switch to turn off a period of time from the first end of the first input source coupled to the second end to the second end coupled to the first end of the second input source as a first switching period, and the control unit controls the second switch to turn off a period of time from the third end of the first input source coupled to the fourth end to the fourth end coupled to the third end of the second input source as a second switching period; the first switching period and the second switching period are approximately equal to the mechanical delay time of switching between the first switch and the second switch.

10. A backup method for a backup circuit with zero current switching, providing a plurality of input sources to backup a load, wherein the plurality of input sources at least include a first input source and a second input source, the backup method comprising the following steps: Controlling one of the first terminals of a first switch to couple to one terminal of the first input source, so that the first terminal to a second terminal of the first switch forms a first power supply path for supplying power to one terminal of the load; Controlling one of the third terminals of a second switch to couple to the other terminal of the first input source, so that the third terminal to a fourth terminal of the second switch constitutes a second power supply path for supplying power to the other terminal of the load; When the input source is to be switched from the first input source to the second input source, controlling a supply current on the first power supply path and the second power supply path to be reduced to less than a threshold; Control the second end of the first switch to switch and couple to the first end corresponding to the second input source; Controlling the fourth end of the second switch to switch and couple to the third end corresponding to the second input source; Detecting a live line current of the first input source to provide a first current signal and detecting a neutral line current of the second input source to provide a second current signal, or detecting a neutral line current of the first input source to provide the first current signal and detecting a live line current of the second input source to provide the second current signal; and Whether the first switch and the second switch are operating normally is determined by the first current signal and the second current signal before and after the first switch and the second switch are switched.

11. The backup method of a backup circuit as claimed in claim 10, wherein after the first switch is switched to couple to the first end corresponding to the second input source and the second switch is switched to couple to the third end corresponding to the second input source, the restriction that the supply current is less than the threshold is released.

12. The backup method of the backup circuit as claimed in claim 10, wherein the second end of the first switch is coupled to one end of the load through a first bypass switch, and a first current limiting unit is connected in parallel with the first bypass switch; the fourth end of the second switch is coupled to the other end of the load through a second bypass switch, and a second current limiting unit is connected in parallel with the second bypass switch, and the backup method of the backup circuit further comprises: The first switch, the first bypass switch and the first current limiting unit are switched from the first input source to the second input source in a backup circuit conduction sequence in which the second end of the first switch is switched to couple to the first end corresponding to the second input source, the first current limiting unit is turned on and the first bypass switch is turned on; and The conduction sequence of the backup circuit of the second switch, the second bypass switch and the second current limiting unit is that the fourth end of the second switch is switched to couple to the third end corresponding to the second input source, the second current limiting unit is turned on and the second bypass switch is turned on. 13 . The backup method of a backup circuit as claimed in claim 12 , wherein when the first bypass switch is turned on and the second bypass switch is turned on, the restriction that the supply current is less than the threshold is released.

14. The backup method of a backup circuit as claimed in claim 12, wherein when the input source is to be switched from the first input source to the second input source, a backup circuit shut-down sequence of the first switch, the first bypass switch and the first current limiting unit is as follows: the first power supply path is disconnected, and the first current limiting unit and the first bypass switch are shut down simultaneously; and The backup circuit of the second switch, the second bypass switch and the second current limiting unit is turned off in the following order: the second power supply path is disconnected, and the second current limiting unit and the second bypass switch are turned off simultaneously.

15. The redundancy method of a redundancy circuit as claimed in claim 10, wherein a first control signal is used to excite the first switch so that the first switch is switched to couple to the first terminal corresponding to the second input source; and A second control signal is used to excite the second switch so that the second switch is switched to couple to the third terminal corresponding to the second input source; the first control signal and the second control signal are a pulse.

16. The backup method for a backup circuit as described in claim 10, wherein the time period from when the first end of the first input source corresponding to the first input source is coupled to the second end to when the second end is coupled to the first end of the second input source is a first switching time period, and the time period from when the second end of the first input source corresponding to the third end is coupled to the fourth end to when the fourth end is coupled to the third end of the second input source is a second switching time period; the first switching time period and the second switching time period are approximately equal to the mechanical delay time of switching between the first switch and the second switch.

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