CN114252690A - Voltage isolation circuit - Google Patents
Voltage isolation circuit Download PDFInfo
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- CN114252690A CN114252690A CN202010993814.5A CN202010993814A CN114252690A CN 114252690 A CN114252690 A CN 114252690A CN 202010993814 A CN202010993814 A CN 202010993814A CN 114252690 A CN114252690 A CN 114252690A
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The application provides a voltage isolation circuit, electric connection is in a plurality of power supplies, voltage isolation circuit contains series switch group, parallel switch group and first high impedance component. The series switch set is controlled by a first control signal and comprises a transistor, and when the series switch set is conducted, the plurality of power supplies are electrically connected in series in the first current loop. The parallel switch set is controlled by a second control signal, and when the parallel switch set is conducted, the plurality of power supplies are electrically connected in parallel in the second current loop. The first high impedance component electrically connects the transistors in parallel. The transistor is arranged in the first current loop, the first high-impedance component is provided with a measuring end point, and the impedance values from the measuring end point to two ends of the first high-impedance component are the same.
Description
Technical Field
The present invention relates to a voltage isolation circuit, and more particularly, to a voltage isolation circuit connected between a power supply and a load device.
Background
Conventionally, in order to test a manufactured load device (such as a battery), a power supply is often used to provide a test voltage and current to measure electrical parameters of the load device during charging. The power supply with more functions can provide voltage and current to the load device, and can reversely receive and measure the voltage and current from the load device to measure the electrical parameters of the load device during discharging. However, with the rapid development of various power storage technologies, the rated power of the load device is higher and higher, and a single power supply may not be able to provide sufficient charging voltage and current to the load device, or may not be able to measure the voltage and current output by the load device through the single power supply.
In order to deal with the above problem, a plurality of power supplies are often connected in series. Referring to fig. 1, fig. 1 is a circuit diagram of a conventional power supply and a load device. As shown in fig. 1, the power supply 91, the power supply 92 and the power supply 93 are, for example, all of the same type, and the power supply 91, the power supply 92 and the power supply 93 are connected in series in order to provide a higher voltage to the load device DUT. In order to isolate the load device DUT from the power supplies 91-93, a switching unit 94 is also typically provided between the load device DUT and the power supply 93. In practice, although such a series connection can provide a sufficiently large voltage, when the power supplies 91, 92 and 93 are used to measure the voltage of the load device DUT, the problem of the power supplies being unable to read the voltage occurs. For example, assuming that the voltage across the load device DUT has 1000 volts (V), in the circuit configuration of fig. 1, the 1000V is almost across the switch unit 94 because the impedance across the switch unit 94 is much larger than the internal impedance of the power supply 91, the power supply 92 and the power supply 93. Obviously, in the case that the cross-over voltages carried by the power supplies 91, 92 and 93 are extremely small, the power supplies 91, 92 and 93 cannot read out the correct voltage values.
In addition, if the power supply 91, the power supply 92 and the power supply 93 are connected in series, it should be understood by those skilled in the art that the circuit architecture of fig. 1 can only provide high voltage to the load device DUT. If the load device DUT needs to be tested with a high current, the circuit architecture of fig. 1 can no longer be used, which also reduces the efficiency of the test. Accordingly, there is a need for a new voltage isolation circuit that, in addition to being able to switchably provide high voltage and high current, also allows the power supply to accurately sense the voltage across the load device DUT.
Disclosure of Invention
The present application provides a voltage isolation circuit disposed between a power supply and a load device. When the power supply supplies power to the load device, the voltage isolation circuit can provide high voltage and high current in a switching mode, and when the power supply measures the load device, the voltage isolation circuit can enable the power supply to correctly read the voltage across the load device.
The application provides a voltage isolation circuit, which is electrically connected between a first power supply and a second power supply, and comprises a first transistor, a second transistor, a third transistor and a first high impedance component. The first transistor is electrically connected to the negative terminal of the first power supply and the positive terminal of the second power supply respectively. The second transistor is electrically connected to the positive terminal of the first power supply and the positive terminal of the second power supply respectively. The third transistor is electrically connected to the negative terminal of the first power supply and the negative terminal of the second power supply, respectively. The first high impedance element is electrically connected in parallel with the first transistor and has a measurement terminal, and the impedance value from the negative terminal of the first power supply to the measurement terminal is the same as the impedance value from the measurement terminal to the positive terminal of the second power supply. The first transistor is controlled by a first control signal, and when the first transistor is conducted, the first power supply and the second power supply are electrically connected in series in the first current loop. The second transistor and the third transistor are controlled by a second control signal, and when the second transistor and the third transistor are conducted, the first power supply and the second power supply are electrically connected in the second current loop in parallel.
In some embodiments, the voltage isolation circuit may include a first terminal, a second terminal, and a switch unit, wherein a positive terminal of the first power supply is connected to the first terminal, a negative terminal of the second power supply is connected to the second terminal, the first terminal and the second terminal are electrically connected to the load device, and the switch unit is configured to selectively connect the first terminal and the second terminal to the first power supply and the second power supply. The voltage isolation circuit may include a reverse connection detection circuit, the reverse connection detection circuit is configured to determine whether the load device is reversely connected when the first power supply and the second power supply operate in the measurement mode, and the switch unit does not conduct the first terminal and the second terminal to the first power supply and the second power supply when the reverse connection detection circuit determines that the load device is reversely connected. In addition, the voltage isolation circuit may include a short detection circuit, the short detection circuit is configured to determine whether the first terminal and the second terminal are shorted when the first power supply and the second power supply operate in the power supply mode, wherein the switch unit does not conduct the first terminal and the second terminal to the first power supply and the second power supply when the short detection circuit determines that the first terminal and the second terminal are shorted.
In some embodiments, after the switch unit does not conduct the first terminal and the second terminal to the first power supply and the second power supply, the first power supply and the second power supply further stop supplying power, and when the output voltages of the first power supply and the second power supply are zero, the first power supply and the second power supply power in a constant current mode.
The application also provides a voltage isolation circuit, electrically connected to a plurality of power supplies, the voltage isolation circuit includes series switch group, parallel switch group and first high impedance component. The series switch set is controlled by a first control signal and comprises a transistor, and when the series switch set is conducted, the plurality of power supplies are electrically connected in series in the first current loop. The parallel switch set is controlled by a second control signal, and when the parallel switch set is conducted, the plurality of power supplies are electrically connected in parallel in the second current loop. The first high impedance component is electrically connected with the transistor in parallel, and two ends of the first high impedance component are respectively connected with one of the plurality of power supplies. The transistor is arranged in the first current loop, and two channel ends of the transistor are respectively connected with one of the power supplies. The first high impedance component has a measuring end point, and the impedance values from the measuring end point to two ends of the first high impedance component are the same.
In some embodiments, the voltage isolation circuit further includes a first terminal and a second terminal, the first terminal is connected to one of the power supplies, the second terminal is connected to the other power supply, and the first terminal and the second terminal are electrically connected to the load device to obtain the external voltage value of the load device. When the total voltage value provided by the plurality of power supplies is the same as the external voltage value, the processing unit provides a first control signal to enable the plurality of power supplies to be electrically connected in series in the first current loop. Or, when the respective voltage value provided by each power supply is the same as the external voltage value, the processing unit provides a second control signal to electrically connect the plurality of power supplies in parallel to the second current loop.
In summary, the voltage isolation circuit provided in the present application can provide high voltage and high current in a switched manner when supplying power to the load device, and can enable the power supply to correctly read the voltage across the load device when measuring the load device. In addition, the voltage isolation circuit provided by the application can also detect the voltage difference between the power supply and the load device, so that the power supply and the load device are prevented from being conducted when the voltage difference is overlarge, and the possibility of danger is reduced.
Other features and embodiments of the present application will be described in detail below with reference to the drawings.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic circuit diagram of a conventional power supply and load device;
FIG. 2 is a circuit schematic of a voltage isolation circuit according to an embodiment of the present application;
FIG. 3 is a circuit schematic of a voltage isolation circuit according to another embodiment of the present application;
fig. 4 is a circuit diagram of a voltage isolation circuit according to still another embodiment of the present application.
Description of the symbols
1. 2, 3 voltage isolation circuit 10, 20, 30 series switch group
12. 22, 32 parallel switch groups 14, 24, 34 switch units
16a, 26a, 36a first end 16b, 26b, 36b second end
91. 92, 93 power supply 94 switch unit
DUT load device Q1-Q6 transistor Z impedance component
Detailed Description
The positional relationship described in the following embodiments includes: the top, bottom, left and right, unless otherwise indicated, are based on the orientation of the elements in the drawings.
Referring to fig. 2, fig. 2 is a circuit diagram of a voltage isolation circuit according to an embodiment of the present application. As shown in fig. 2, the voltage isolation circuit 1 is provided between a power supply 91 (first power supply), a power supply 92 (second power supply), and a load device DUT. The voltage isolation circuit 1 includes a series switch group 10, a parallel switch group 12, and a switch unit 14, and is connected to a positive terminal of the load device DUT by a first terminal 16a and to a negative terminal of the load device DUT by a second terminal 16 b. In practice, the load device DUT may be a large capacitor or a high-capacity battery, and the present embodiment does not limit the kind of the capacitor or the battery. In addition, the power supply 91 and the power supply 92 may have a power supply mode and a measurement mode, wherein the power supply mode indicates that the power supply 91 and the power supply 92 provide voltage and current to the load device DUT, and the measurement mode indicates that the power supply 91 and the power supply 92 can measure the voltage and current from the load device DUT. In addition, although fig. 2 illustrates two power supplies as an example, the number of power supplies is not limited in the present embodiment. The following description will be made of each component in the voltage isolation circuit 1.
The series switch group 10 may have a transistor Q1 (first transistor) therein, and the parallel switch group 12 may have a transistor Q3 (second transistor) and a transistor Q5 (third transistor) therein. Here, since the transistor Q1, the transistor Q3, and the transistor Q5 are used as switches, the transistor Q1, the transistor Q3, and the transistor Q5 shown in fig. 2 look like components at both ends. However, it should be understood by those skilled in the art that the two terminals of the transistor Q1, the transistor Q3 and the transistor Q5 shown in fig. 2 are channel terminals, and the transistor Q1, the transistor Q3 and the transistor Q5 may further have respective control terminals (not shown) for receiving corresponding control signals. In one example, if the transistor Q1 is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the two channel terminals of the transistor Q1 are a source (source) and a drain (drain). The control terminal of the transistor Q1 may be a gate (gate) for receiving the first control signal, and the transistor Q1 is turned on or off by the first control signal. It should be understood by those skilled in the art that the device characteristics of the transistor Q3 and the transistor Q5 may be the same as the transistor Q1, and the control terminals of the transistor Q3 and the transistor Q5 may be controlled by the second control signal and the third control signal, respectively, so that the transistor Q3 and the transistor Q5 are turned on or off, which is not described herein again.
The switching unit 14 may be disposed between the power supplies 91, 92 and the load device DUT. The switching unit 14 may, for example, consist of one or more relays. The present embodiment does not limit the internal circuit architecture of the switch unit 14, and it is consistent with the scope of the switch unit 14 of the present embodiment as long as the power supply 91 and the power supply 92 can selectively electrically connect the load device DUT through the switch unit 14. In one example, the switch unit 14 can connect the positive terminal of the power supply 91 and the negative terminal of the power supply 92, and can selectively conduct the positive terminal of the power supply 91 to the first terminal 16a and/or conduct the negative terminal of the power supply 92 to the second terminal 16 b. It should be noted that the switch unit 14 is not a necessary component of the voltage isolation circuit 1, that is, the voltage isolation circuit 1 of the present embodiment does not necessarily need the switch unit 14 and should also be able to implement the basic functions of connecting a plurality of power supplies in series and connecting a plurality of power supplies in parallel.
For the circuit of fig. 2, the two channel terminals of the transistor Q1 may be respectively connected to the negative terminal of the power supply 91 and the positive terminal of the power supply 92. When the series switch bank 10 is turned on (i.e., the transistor Q1 is turned on), the power supply 91 may be connected in series with the power supply 92. In addition, two channel terminals of the transistor Q3 may be respectively connected to the positive terminal of the power supply 91 and the positive terminal of the power supply 92, and two channel terminals of the transistor Q5 may be respectively connected to the negative terminal of the power supply 91 and the negative terminal of the power supply 92. When the parallel switch 12 is turned on (i.e., the transistor Q3 and the transistor Q5 are turned on simultaneously), the power supply 91 can be connected in parallel with the power supply 92.
In practice, the user can select the operation mode of the power supply 91 and the power supply 92 and select whether the power supply 91 and the power supply 92 are connected in series or in parallel according to the item to be tested of the load device DUT. In one example, assuming that a user needs to test the load device DUT with a large voltage, the user may first set the power supply 91 and the power supply 92 to operate in the power mode. Then, the user may control the voltage isolation circuit 1 through a processing unit (e.g., a computer) such that the series switch set 10 is turned on and the parallel switch set 12 is turned off. In detail, the processing unit may send the first control signal to turn on the transistor Q1 (at this time, the transistor Q3 and the transistor Q5 are not turned on), so that the power supply 91 and the power supply 92 may form a series-connected current loop (the first current loop). It should be understood by those skilled in the art that, since the power supply 91 and the power supply 92 operate in the power supply mode, when the power supply 91 is connected in series with the power supply 92, there may be a large voltage difference between the positive terminal of the power supply 91 and the negative terminal of the power supply 92. For convenience of illustration, the switch unit 14 may be set to the on state, so that the voltage across the first terminal 16a and the second terminal 16b is the sum of the output voltages of the power supply 91 and the power supply 92, and thus the load device DUT can be tested with a larger voltage.
On the other hand, assuming that the user needs to test the load device DUT with a large current, the user can also set the power supply 91 and the power supply 92 to operate in the power supply mode. And, the user can control the voltage isolation circuit 1 through a processing unit (e.g., a computer) such that the parallel switch set 12 is turned on and the series switch set 10 is turned off. In other words, the processing unit may send the second and third control signals to make the transistors Q3 and Q5 be turned on simultaneously (at this time, the transistor Q1 is not turned on), so that the power supply 91 and the power supply 92 may form a parallel current loop (the second current loop). It should be understood by those skilled in the art that since the power supply 91 and the power supply 92 operate in the power supply mode, the power supply 91 and the power supply 92 can provide a superimposed current when the power supply 91 is connected in parallel with the power supply 92. Similarly, assuming that the switch unit 14 is set to the conducting state, the sum of the output currents of the power supply 91 and the power supply 92 can be fed into the load device DUT from the first terminal 16 a.
As can be seen from the above, the voltage isolation circuit 1 of the present embodiment allows the power supply 91 and the power supply 92 to be connected in series or in parallel. Unlike the conventional example illustrated in fig. 1, the voltage isolation circuit 1 provided in the present embodiment does not require the wires of the power supply 91 and the power supply 92 to be detached, and has a function of outputting a large voltage or a large current to test the load device DUT. Of course, in the above example, the power supply 91 and the power supply 92 are operated in the power supply mode, and the power supply 91 and the power supply 92 may also be operated in the measurement mode to measure the voltage across the load device DUT (the external voltage value). As can be seen from fig. 2, the voltage isolation circuit 1 further comprises a high impedance component Z (first high impedance component), and the high impedance component Z is electrically connected in parallel with the transistor Q1. In practice, since the high impedance component Z has a very high impedance, the current flowing through the high impedance component Z can be substantially ignored. In addition, the high impedance device Z has a measurement terminal (not shown), and the impedance value from the measurement terminal to both ends of the high impedance device Z is the same. In one example, the power supply 91 may have one probe electrically connected to the measurement terminal of the high impedance device Z and another probe electrically connected to the positive terminal of the power supply 91. Similarly, the power supply 92 may have one probe electrically connected to the measurement terminal of the high impedance device Z and another probe electrically connected to the negative terminal of itself (the power supply 92).
For the example illustrated in fig. 2, assuming that the user needs to measure the voltage across the load device DUT, the user can set the power supply 91 and the power supply 92 to operate in the measurement mode, and set both the series switch set 10 and the parallel switch set 12 to the off state. As can be understood from the above description, assuming that the switch unit 14 is set to be in the conducting state, it can be understood by those skilled in the art that the voltage across the load device DUT almost entirely crosses the high impedance component Z. At this time, the power supply 91 can measure the voltage across the high impedance device Z from its positive terminal to its measurement terminal, and the power supply 92 can measure the voltage across the high impedance device Z from its measurement terminal to its negative terminal. Then, the voltage across the load device DUT can be obtained by adding the voltage across the power supplies 91 and 92.
For practical purposes, assuming that the upper voltage limits that can be measured by the power supplies 91 and 92 are 600V, when the load device DUT is a large-capacity battery (for example, the voltage across the load device DUT is 1000V), theoretically, neither power supply can measure the voltage across the load device DUT alone. However, since the voltage isolation circuit 1 of the present application has the high impedance component Z, the power supply 91 and the power supply 92 respectively measure half of the voltage across the load device DUT, that is, each measure 500V (less than 600V of the upper limit). Finally, the 500V measured by the power supply 91 and the power supply 92 are added to obtain the voltage across the load device DUT. Therefore, the voltage isolation circuit 1 of the present embodiment includes the high impedance device Z, so that the upper limit of the voltage across the load device DUT can be increased.
It is worth mentioning that when testing the load device DUT, the load device DUT may already have a certain level of cross-over voltage. At this time, if the power supply 91, the power supply 92 and the load device DUT are directly turned on, the load device DUT is connected in series or in parallel with the power supply 91 and the power supply 92, and sparks and inrush currents may be generated in practice. In order to deal with the above problem, the present embodiment proposes a mechanism for connecting the load device DUT after precharging the voltage isolation circuit 1. In one example, the voltage isolation circuit 1 may first detect the voltage across the load device DUT by using the aforementioned means for measuring the voltage across the load device DUT (external voltage value). Next, if the power supply 91 and the power supply 92 are connected in series, the power supply 91 and the power supply 92 may be precharged first, so that the total voltage value of the series connection of the power supply 91 and the power supply 92 is the same as the external voltage value. When there is no voltage difference between the load device DUT and the power supplies 91-92, the series switch group 10 or the switch unit 14 is turned on, so as to effectively reduce the spark and surge current. Similarly, if the power supply 91 and the power supply 92 are to be connected in parallel, the power supply 91 and the power supply 92 may be precharged first, so that the respective voltage values of the power supply 91 and the power supply 92 themselves are the same as the external voltage value. When there is no voltage difference between the load device DUT and the power supply 91, or between the load device DUT and the power supply 92, the parallel switch set 12 or the switch unit 14 is turned on, which also effectively reduces the spark and surge current.
In practice, the voltage isolation circuit 1 of the present application is not limited to be connected to two power supplies, for example, the following embodiment will demonstrate an example in which the voltage isolation circuit is connected to a plurality of power supplies. Referring to fig. 2 and fig. 3 together, fig. 3 is a circuit schematic diagram of a voltage isolation circuit according to another embodiment of the present application. As shown, the voltage isolation circuit 2 may be connected between a power supply 91, a power supply 92, a power supply 93, and a load device DUT. As in the embodiment of fig. 2, the voltage isolation circuit 2 also includes a series switch bank 20, a parallel switch bank 22 and a switch unit 24, and is connected by a first terminal 26a to the positive terminal of the load device DUT and by a second terminal 26b to the negative terminal of the load device DUT. However, unlike the embodiment of fig. 2, the number of transistors in the series switch bank 20 and the parallel switch bank 22 varies with the number of power supplies. For example, the series switch group 20 may have a transistor Q1 and a transistor Q2 therein, and the parallel switch group 22 may have a transistor Q3, a transistor Q4, a transistor Q5, and a transistor Q6 therein. In addition, the number of the high impedance components Z is also different, for example, the transistor Q1 and the transistor Q2 of the present embodiment may be respectively connected in parallel with one high impedance component Z.
In practical operation, assuming that a user needs to test the load device DUT with a large voltage, the user can set the power supply 91, the power supply 92, and the power supply 93 to operate in the power supply mode. As in the previous embodiment, the series switch set 20 is turned on, and the parallel switch set 22 is turned off. At this time, the transistor Q1 and the transistor Q2 are turned on, so that the power supply 91, the power supply 92 and the power supply 93 can form a series current loop. On the other hand, assuming that the user needs to test the load device DUT with a large current, the user can also set the power supply 91, the power supply 92, and the power supply 93 to operate in the power supply mode. The parallel switch group 22 is turned on, and the series switch group 20 is turned off. At this time, the transistors Q3 to Q6 are turned on, so that the power supply 91, the power supply 92 and the power supply 93 can form a parallel current loop. Similarly, the voltage isolation circuit 2 of the present embodiment demonstrates that the plurality of power supplies can be switched between the series connection and the parallel connection, and has a function of outputting a large voltage or a large current to test the load device DUT without requiring the mounting and dismounting of the plurality of power supplies.
Further, assuming that the user needs to measure the voltage across the load device DUT, the user can set the power supply 91, the power supply 92, and the power supply 93 to operate in the measurement mode, and set the series switch group 20 and the parallel switch group 22 to be in the off state. Similar to the previous embodiment, the power supply 91 may measure the voltage between its positive terminal and the measurement terminal of the first high impedance device Z, the power supply 92 may measure the voltage between the measurement terminal of the first high impedance device Z and the measurement terminal of the second high impedance device Z, and the power supply 93 may measure the voltage between the measurement terminal of the second high impedance device Z and its negative terminal. The present embodiment can also increase the upper limit of the voltage across the load device DUT. On the other hand, compared to fig. 1, since the voltage across the load device DUT of fig. 1 (for example, 1000V) falls on the switch unit 94, the switch unit 94 needs to withstand up to 1000V. Conversely, because the transistor Q1 is disposed between the power supply 91 and the power supply 92, and the transistor Q2 is disposed between the power supply 92 and the power supply 93, the transistor Q1 and the transistor Q2 only need to carry half of the voltage across the load device DUT, e.g., 500V. As will be appreciated by those skilled in the art, the voltage withstanding requirement of the switch unit 94 is much higher than that of the transistor Q1 and the transistor Q2 of the present embodiment, and it is obvious that the voltage isolation circuit 2 of the present embodiment can have a lower cost.
In addition, since a user may inadvertently malfunction when connecting the load device DUT to the voltage isolation circuit, there is a high possibility of damage to the power supply. In order to avoid the above problems, the voltage isolation circuit of the present application may further have a reverse connection detection function and a short circuit detection function. Referring to fig. 3 and 4 together, fig. 4 is a circuit schematic diagram of a voltage isolation circuit according to another embodiment of the present application. As shown, the voltage isolation circuit 3 of fig. 4 is identical to the voltage isolation circuit 2 of fig. 3 in that the voltage isolation circuit 3 also has a series switch bank 30, a parallel switch bank 32 and a switch unit 34, and is connected by a first end 36a to the positive terminal of the load device DUT and by a second end 36b to the negative terminal of the load device DUT. The series switch group 30 may include a transistor Q1 and a transistor Q2, the parallel switch group 32 may include a transistor Q3, a transistor Q4, a transistor Q5, and a transistor Q6, and the transistor Q1 and the transistor Q2 may be connected in parallel with each other by a high impedance component Z.
In contrast to the voltage isolation circuit 2 of fig. 3, the voltage isolation circuit 3 further comprises a diode 38a and a protection component 38 b. In one example, assume that a user needs to measure the voltage across the load device DUT and set the power supply 91, the power supply 92, and the power supply 93 to operate in the measurement mode. At this time, if the user erroneously connects the positive terminal of the load device DUT to the second terminal 36b and connects the negative terminal of the load device DUT to the first terminal 36a, the load device DUT may be connected in reverse. Since the voltage across the load device DUT is very large, it is very likely that a large current will momentarily flood the power supply and voltage isolation circuitry from the incorrect terminal (e.g., the second terminal 36b), causing serious damage. To avoid the above-mentioned malfunction, the diode 38a of the present embodiment provides a current path from bottom to top (from the second end 36b to the first end 36a) (reverse connection detection loop). When the load device DUT is reverse connected, a large current entering from the second terminal 36b can flow to the first terminal 36a via the diode 38a and back to the load device DUT, avoiding the large current from damaging other circuit components of the voltage isolation circuit 3 or the power supply.
In addition, the protection component 38b provided in this embodiment may be a fuse, and when the current entering from the second end 36b is too large, the protection component 38b will automatically burn to form an open circuit, so as to protect other circuit components or power supplies of the voltage isolation circuit 3. In one example, the voltage isolation circuit 3 may be a multi-circuit board structure, for example, a mother circuit board may be provided, and more than one daughter circuit boards may be inserted. In practice, the protection component 38b may be disposed on the daughter circuit board, and other circuit components in the voltage isolation circuit 3 may be disposed on the mother circuit board. In the above example of the protection component 38b being burned out, since other circuit components of the mother circuit board are all operating normally, the voltage isolation circuit 3 of the present embodiment does not need to be removed from the whole set for maintenance or replacement, but only needs to be replaced with a new daughter circuit board (i.e. a new protection component 38 b).
It should be noted that the protection component 38b is not necessarily a necessary component, and the present embodiment can also achieve similar functions by controlling the switch unit 34. For example, it is also possible to provide the voltage isolation circuit 3 with a component for detecting current, such as a hall sensor (not shown) in the reverse connection detection loop. When the current value detected by the Hall sensor exceeds a threshold value, the load device DUT can be judged to be reversely connected. At this time, as long as the switch unit 34 is controlled to be open-circuited, that is, the first terminal 36a and the second terminal 36b are not conducted to the plurality of power supplies, other circuit components or the power supplies of the voltage isolation circuit 3 can be protected. In this way, the function of the protection component 38b can be replaced by the switch unit 34. In addition, when the current value detected by the hall sensor exceeds a threshold value, the voltage isolation circuit 3 may also issue an alarm to prompt the user that the load device DUT is connected reversely, which is not limited in this embodiment.
The human error is not limited to the voltage across the load device DUT, and may occur when a large current is fed into the load device DUT. In practical terms, when the power supply 91, the power supply 92 and the power supply 93 are set to operate in the power supply mode, if the first terminal 36a and the second terminal 36b are inadvertently shorted together or a short circuit is temporarily formed inside the load device DUT, a spark or a surge current may be generated. The present embodiment also has a corresponding control strategy for the case where the load device DUT is short-circuited. In one example, a current detecting element, such as the aforementioned hall sensor (not shown), may be disposed at the first end 36a or the second end 36 b. At this time, if the load device DUT between the first end 36a and the second end 36b is short-circuited, it indicates that the current value measured by the hall sensor exceeds a threshold value, and it can be determined that the load device DUT is short-circuited. Similar to the above example of the reverse connection load device DUT, the protection effect of other circuit components or power supplies of the voltage isolation circuit 3 can be achieved as long as the switch unit 34 is controlled to be open, i.e., not to conduct the first terminal 36a and the second terminal 36b to the plurality of power supplies.
In view of the above example, the present embodiment also provides a means for electrically reconnecting the voltage isolation circuit 3 to the load device DUT, especially in the case where the voltage isolation circuit 3 is reconnected to the load device DUT that is short-circuited. First, after the switch unit 34 is opened, the processing unit (e.g., a computer) automatically turns off the power supply 91, the power supply 92 and the power supply 93, or automatically sets the output voltages of the power supply 91, the power supply 92 and the power supply 93 to zero. Then, after the output voltages of the power supply 91, the power supply 92 and the power supply 93 are zero, the processing unit will provide the control signal to make the switch unit 34 turn on again. Since the output voltages of the power supply 91, the power supply 92 and the power supply 93 at this time are zero and there is almost no voltage difference between the short-circuited load devices DUT, the occurrence of sparks when the switching unit 34 is turned back on can be avoided. In addition, when the load device DUT is out of the short circuit state, the power supply 91, the power supply 92 and the power supply 93 can charge the load device DUT in a constant current mode to resume normal operation. It should be noted that the switch unit 34 of the present embodiment is also an unnecessary component, and the same effect should be obtained by controlling the series switch group 30 and the parallel switch group 32.
For example, without the switch unit 34, if the load device DUT between the first terminal 36a and the second terminal 36b is short-circuited, the series switch set 30 and the parallel switch set 32 can be turned off immediately to protect the plurality of power supplies instantaneously. After the plurality of power supplies disconnect the load device DUT, the processing unit (e.g., computer) automatically turns off the plurality of power supplies, or automatically sets the output voltages of the plurality of power supplies to zero. The processing unit then provides a control signal to turn the series switch set 30 or the parallel switch set 32 back on again. Likewise, because there is little voltage difference between the multiple power supplies and the shorted load device DUT, sparking can be avoided when either the series switch bank 30 or the parallel switch bank 32 is turned back on. Finally, when the load device DUT is out of the short circuit state, the power supply 91, the power supply 92 and the power supply 93 can charge the load device DUT in the constant current mode to resume normal operation.
In summary, the voltage isolation circuit provided in the present application can provide high voltage and high current in a switched manner when supplying power to the load device, and can enable the power supply to correctly read the voltage across the load device when measuring the load device. In addition, the voltage isolation circuit provided by the application can also detect the voltage difference between the power supply and the load device, so that the power supply and the load device are prevented from being conducted when the voltage difference is overlarge, and the possibility of danger is reduced.
The above-described embodiments and/or implementations are only for illustrating the preferred embodiments and/or implementations of the technology of the present application, and are not intended to limit the implementations of the technology of the present application in any way, and those skilled in the art can make modifications or changes to other equivalent embodiments without departing from the scope of the technology disclosed in the present application, but should be construed as technology or implementations substantially the same as the present application.
Claims (9)
1. A voltage isolation circuit electrically connected between a first power supply and a second power supply, the voltage isolation circuit comprising:
a first transistor electrically connected to the negative terminal of the first power supply and the positive terminal of the second power supply, respectively;
a second transistor electrically connected to the positive terminal of the first power supply and the positive terminal of the second power supply, respectively;
a third transistor electrically connected to the negative terminal of the first power supply and the negative terminal of the second power supply, respectively; and
a first high impedance element electrically connected in parallel to the first transistor and having a measurement terminal, the impedance of the negative terminal of the first power supply to the measurement terminal being the same as the impedance of the measurement terminal to the positive terminal of the second power supply;
the first transistor is controlled by a first control signal, and when the first transistor is conducted, the first power supply and the second power supply are electrically connected in series in a first current loop;
the second transistor and the third transistor are controlled by a second control signal, and when the second transistor and the third transistor are conducted, the first power supply and the second power supply are electrically connected in a second current loop in parallel.
2. The voltage isolation circuit of claim 1, further comprising a first terminal, a second terminal, and a switch unit, wherein a positive terminal of the first power supply is connected to the first terminal, a negative terminal of the second power supply is connected to the second terminal, the first terminal and the second terminal are electrically connected to a load device, and the switch unit is configured to selectively connect the first terminal and the second terminal to the first power supply and the second power supply.
3. The voltage isolation circuit of claim 2, further comprising a reverse connection detection circuit, wherein when the first power supply and the second power supply operate in a measurement mode, the reverse connection detection circuit is configured to determine whether the load device is reverse connected, and when the reverse connection detection circuit determines that the load device is reverse connected, the switch unit does not conduct the first terminal and the second terminal to the first power supply and the second power supply.
4. The voltage isolation circuit of claim 2, further comprising a short detection circuit for determining whether the first terminal and the second terminal are shorted when the first power supply and the second power supply operate in a power supply mode, wherein the switch unit does not conduct the first terminal and the second terminal to the first power supply and the second power supply when the short detection circuit determines that the first terminal and the second terminal are shorted.
5. The voltage isolation circuit of claim 4, wherein the switch unit turns off the first terminal and the second terminal after the first power supply and the second power supply, the first power supply and the second power supply further stop supplying power, and the first power supply and the second power supply power in a constant current mode after the output voltages of the first power supply and the second power supply are zero.
6. A voltage isolation circuit electrically connected to a plurality of power supplies, the voltage isolation circuit comprising:
the series switch group is controlled by a first control signal and comprises a transistor, and when the series switch group is conducted, the power supplies are electrically connected in series in a first current loop;
the parallel switch group is controlled by a second control signal, and when the parallel switch group is conducted, the power supplies are electrically connected in parallel in a second current loop; and
a first high impedance component, which is electrically connected with the transistor in parallel, and two ends of the first high impedance component are respectively connected with one of the power supplies;
the transistor is arranged in the first current loop, and two channel ends of the transistor are respectively connected with one of the power supplies;
the first high impedance component has a measuring end point, and the impedance values from the measuring end point to two ends of the first high impedance component are the same.
7. The voltage isolation circuit of claim 6, further comprising a first terminal and a second terminal, wherein the first terminal is connected to one of the power supplies, the second terminal is connected to the other power supply, and the first terminal and the second terminal are electrically connected to a load device to obtain an external voltage value of the load device.
8. The voltage isolation circuit of claim 7, wherein when a total voltage provided by the power supplies is equal to the external voltage, a processing unit provides the first control signal to electrically connect the power supplies in series with the first current loop.
9. The voltage isolation circuit of claim 7, wherein a processing unit provides the second control signal to electrically connect the power supplies in parallel to the second current loop when a respective voltage provided by each of the power supplies is the same as the external voltage.
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| CN202010993814.5A CN114252690A (en) | 2020-09-21 | 2020-09-21 | Voltage isolation circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010993814.5A CN114252690A (en) | 2020-09-21 | 2020-09-21 | Voltage isolation circuit |
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