Low leakage current relay and circuit topology having the same

Abstract

The present invention provides a low-leakage relay and a circuit topology having the low-leakage relay, comprising: an external shielding layer, an external insulating layer, a coil, an intermediate insulating layer, an internal shielding layer, an internal insulating layer, a switch accommodating cavity, and a contact switch; the coil controls the on and off state of the contact switch via an input control signal; the intermediate insulating layer is used to isolate the coil from the internal shielding layer; when the contact switch is closed, a conduction signal is input to and transmitted through the contact switch, and the difference between the input internal shielding signal and the conduction signal is less than or equal to a preset value. When the contact switch is connected, the voltage difference between the internal shielding layer and the contact switch inside the relay is very small, thereby reducing leakage current of the contact switch inside the relay. When the contact switch is disconnected, the contact switch inside the relay is well protected from leakage current by the internal shielding signal.

Description

Technical Field

[0001] The present invention relates to the field of precision measurement technology, and in particular to a low leakage current relay and a circuit topology having the low leakage current relay. Background Art

[0002] With the advancement of semiconductor technology and processing techniques, the development of high-precision manufacturing processes, and the requirements of nanometer-level wafer processing, femtoampere-level current measurement is required. Relay switches are widely used in instrument measurement circuits, signal transmission links, high-precision instrument circuits, ATE, WAT, and other equipment. However, the leakage current of existing relay switches seriously affects precision measurement. The leakage current of a single relay when connected or disconnected can be as high as tens of picoamps. When performing precision measurements, multiple relays are often used. In this case, the leakage current of multiple relays is cumulative, which may reach the nanoampere level. For precision measurements requiring measurements of 0.1pA or 0.01pA, the leakage current is far greater than the measurement accuracy, making it impossible to achieve the performance requirements of circuit measurements.

[0003] The existing solution to reduce leakage current is to continuously increase the physical distance between the various components of the relay, thereby increasing the physical spacing between the signals transmitted by the relay and improving the insulation resistance of the relay itself. However, this will result in a large relay size, which is completely unsuitable for high-density, multi-channel and complex test scenarios.

[0004] In view of this, it is necessary to propose a low leakage current relay and a circuit topology having the low leakage current relay to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a low leakage current relay and a circuit topology having the low leakage current relay, so as to improve the problem that the existing relay is large in size and is incapable of handling high-density, multi-channel complex test scenarios.

[0006] The present invention provides a low leakage current relay, comprising: an external shielding layer, an external insulating layer, a coil, an intermediate insulating layer, an internal shielding layer, an internal insulating layer, a switch accommodating cavity, and a contact switch; an external shielding signal is input into the external shielding layer, and the external shielding layer provides electrical shielding for the internal circuit of the low leakage current relay through the external shielding signal; the external insulating layer is arranged between the external shielding layer and the coil, and is used to isolate the coil from the external shielding layer; the coil is arranged between the external insulating layer and the intermediate insulating layer, and the coil controls the conduction and disconnection of the contact switch through the input control signal; the intermediate insulating layer is arranged between the coil and the internal Between the shielding layers, it is used to isolate the coil from the internal shielding layer; the internal shielding layer is arranged between the intermediate insulating layer and the internal insulating layer, and the internal shielding signal is input into the internal shielding layer; the internal insulating layer is arranged between the internal shielding layer and the switch accommodating cavity, and is used to protect the switch accommodating cavity and isolate the internal shielding layer and the contact switch; the switch accommodating cavity is used to accommodate the contact switch, and is used to provide insulation from the contact switch to the coil and from the contact switch to the outer shell; when the contact switch is closed, the conduction signal is input into the contact switch and transmitted through the contact switch, and the difference between the input internal shielding signal and the conduction signal is less than or equal to the preset value.

[0007] The low-leakage relay provided by the present invention has the following beneficial effects: the internal shielding layer shields the electromagnetic interference of the coil on the contact switch, and the intermediate insulating layer isolates leakage current from the contact switch through the internal insulating layer to the coil. When the contact switch is connected, the voltage difference between the internal shielding layer and the contact switch inside the relay is very small, and the voltage difference between the two end points of the contact switch and the internal shielding layer is also very small. Therefore, the contact switch no longer leaks directly to the coil and external shielding layer, thereby reducing leakage current of the contact switch inside the relay. When the contact switch is disconnected, the contact switch inside the relay is well protected from leakage current by the internal shielding signal.

[0008] The present invention also provides a multi-circuit topology with a low-leakage relay, including the low-leakage relay in the above embodiment, and the multi-circuit topology includes n single-circuit topologies as in the above embodiment, the first end of the contact switch of the first relay in the n single-circuit topologies is connected to a first external circuit, there are n second external circuits and they correspond one-to-one to the n single-circuit topologies, and the second external circuits are connected to the second end of the contact switch of the second relay of the corresponding single-circuit topology, wherein n is a positive integer greater than 1.

[0009] The beneficial effects of the multi-channel circuit topology provided by the present invention are: in a connected branch in the multi-channel circuit topology, the internal shielding signal provides low leakage current protection for the contact switch of the first relay in the connected branch to the internal shielding layer of the first relay, and for the contact switch of the second relay in the connected branch to the internal shielding layer of the second relay; in a disconnected branch in the multi-channel circuit topology, the voltages at both ends of the contact switch of the first relay are approximately equal, so that the leakage current at the first end of the contact switch of the first relay in the disconnected branch is very small.

[0010] In one embodiment, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in all single-circuit topologies are connected to the first external circuit; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in all single-circuit topologies are connected to the first external circuit via a first protection voltage module; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in each single-circuit topology are respectively connected to the second external circuit of the corresponding branch; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in each single-circuit topology are connected to the second external circuit of the corresponding branch via a second protection voltage module. The beneficial effect of this solution is that by setting a first external circuit or a first protection voltage module at the first end of the contact switch of the first relay in all branches, leakage protection is provided for the first end of the contact switch of the first relay in all branches; or, by setting a second external circuit or a second protection voltage module at the second end of the contact switch of the second relay in all branches, leakage protection is provided for the second end of the contact switch of the second relay in all branches.

[0011] In one embodiment, when a multi-circuit topology is connected, the first external circuit is connected to the second external circuit via at least one connected single-circuit topology, while the single-circuit topologies of the remaining branches are disconnected. When a multi-circuit topology is disconnected, all single-circuit topologies are disconnected. This solution has the beneficial effect of enabling one or more branches in a multi-circuit topology based on the actual detection scenario, while disabling the remaining branches. Both connected and disconnected branches have a low leakage current effect, ensuring a low total leakage current. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of leakage current when a single relay is connected.

[0013] Figure 2 This is a schematic diagram of leakage current when a single relay is disconnected.

[0014] Figure 3This is a schematic diagram of a circuit topology using an existing single relay;

[0015] Figure 4 is a schematic diagram of a low leakage current relay of the present invention;

[0016] Figure 5 for Figure 4 Cross-sectional view in the direction of section A;

[0017] Figure 6 for Figure 4 Cross-sectional view in the direction of section B;

[0018] Figure 7 for Figure 4 Sectional view in the longitudinal direction;

[0019] Figure 8 This is a schematic diagram of the low leakage current relay of the present invention after removing the outer shielding layer and the outer insulation layer;

[0020] Figure 9 is a schematic diagram of a low leakage current relay of the present invention in a first embodiment;

[0021] Figure 10 is a schematic diagram of a low leakage current relay of the present invention in a second embodiment;

[0022] Figure 11 is a schematic diagram of a low leakage current relay according to a third embodiment of the present invention;

[0023] Figure 12 is a schematic diagram of a low leakage current relay according to a fourth embodiment of the present invention;

[0024] Figure 13 A schematic diagram of leakage current when the low leakage current relay of the present invention is connected;

[0025] Figure 14 A schematic diagram of leakage current when the low leakage current relay of the present invention is disconnected;

[0026] Figure 15 A schematic diagram of a single-circuit topology with a low leakage current relay of the present invention;

[0027] Figure 16 Schematic diagram of a single-circuit topology with a low leakage current relay of the present invention in an initial state, a connected state, and a disconnected state;

[0028] Figure 17 A schematic diagram of leakage current when a single-circuit topology with a low leakage current relay of the present invention is connected;

[0029] Figure 18 A schematic diagram of leakage current when a single-circuit topology with a low leakage current relay of the present invention is disconnected;

[0030] Figure 19 A schematic diagram of a multi-circuit topology with a low leakage current relay according to the present invention;

[0031] Figure 20 A schematic diagram of leakage current when at least one branch of a multi-circuit topology with a low leakage current relay of the present invention is connected;

[0032] Figure 21 The diagram is a schematic diagram of leakage current when a multi-circuit topology with a low leakage current relay of the present invention is disconnected.

[0033] Explanation of reference numerals: external shielding layer 110; external insulating layer 120; coil 130; intermediate insulating layer 140; internal shielding layer 150; internal insulating layer 160; vacuum tube 170; contact switch 180; insulating sealing plug 190; first relay SW1; second relay SW2; third relay SW3. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] Figure 1 This is a schematic diagram of leakage current when a single relay is connected. Figure 2 This is a schematic diagram of leakage current when a single relay is disconnected. Figure 3 For a schematic diagram of the circuit topology using an existing single relay, see Figures 1 to 3 , taking the V / I source input voltage V0 = 200V and input current Iin = 10nA as an example, the insulation resistance IR00 and IR01 between the external shielding layer and the two ends of the contact switch are both equal to 1×10 13 Ω, the insulation resistance R10 and R11 between the coil and the two ends of the contact switch are both equal to 1×10 13 Ω, when the contact switch is disconnected, the insulation resistance Roff = 1×10 14Ω, when the contact switch is connected, the insulation resistance Ron = 150mΩ, IL00 and IL01 are the currents leaking from the contact switch to the coil, IL10 and IL11 are the currents leaking from both ends of the contact switch to the external shielding layer. Since the resistance of the relay contact switch is very small when it is turned on, the output voltage V1 = V0-Iin*Ron = V0-10nA*150mΩ. Therefore, the output voltage V1 is approximately equal to the input voltage V0. When a single relay is connected, the total leakage current IleakageOn = IL00+IL01+IL10+IL11 = 79.5pA. When a single relay is disconnected, the total leakage current IleakageOff =IL00+IL01+IL20=42pA. If the circuit topology includes multiple branches, the leakage current of the entire circuit is cumulative. For example, if the circuit topology contains 51 branches, the total leakage current when the circuit topology opens one branch and closes the other 50 branches is Ileakage=IleakageOn+50*ILeakageOff=2.1795nA. This shows that the leakage current when a single relay is connected or disconnected may be as high as tens of pA. The leakage current of a circuit topology composed of a single relay reaches the nA level, which cannot meet the precision measurement requirements of 0.1pA or 0.01pA.

[0036] Regarding the above existing technical problems, see Figures 4 to 8 An embodiment of the present invention provides a low-leakage current relay, comprising: an external shielding layer 110, an external insulating layer 120, a coil 130, an intermediate insulating layer 140, an internal shielding layer 150, an internal insulating layer 160, a switch accommodating chamber, and a contact switch 180. An external shielding signal is input to the external shielding layer 110, and the external shielding layer 110 uses the external shielding signal to provide electrical shielding for the internal circuit of the low-leakage current relay. The external shielding layer 110 is provided with an external shielding layer signal pin Shield1, which is connected to a certain voltage level to achieve electrical shielding. The external insulating layer 120 is disposed between the external shielding layer 110 and the coil 130 to isolate the coil 130 from the external shielding layer 110. The coil 130 is disposed between the external insulating layer 120 and the intermediate insulating layer 140, and the coil 130 controls the on and off state of the contact switch 180 via an input control signal. Coil 130 has a positive signal pin, Coil+, and a negative signal pin, Coil-, at either end. These pins are connected to the control circuit. Coil 130 powers the relay's opening and closing operations. Applying a voltage to these pins, Coil+ and Coil-, opens or closes the relay's internal contact switch 180. An intermediate insulating layer 140 is provided between coil 130 and internal shielding layer 150 to isolate them from each other.

[0037] Internal shielding layer 150 is disposed between intermediate insulating layer 140 and internal insulating layer 160 and can completely surround contact switch 180. An internal shielding signal is input into internal shielding layer 150 to shield contact switch 180 from electromagnetic interference from coil 130. Internal shielding layer 150 is provided with internal shielding layer signal pin Shield0, which connects to an external circuit and receives an internal shielding signal. Internal insulating layer 160 is disposed between internal shielding layer 150 and the switch housing, protecting the switch housing and isolating internal shielding layer 150 from contact switch 180. The switch housing houses contact switch 180 and provides insulation from contact switch 180 to coil 130 and from the housing. The switch accommodating cavity is a vacuum tube 170 with an internal vacuum or an accommodating cavity filled with an inert gas. Insulating sealing plugs 190 are provided at both ends of the vacuum tube 170 to seal the vacuum tube 170. Contact switch signal pins IO0 and IO1 are provided at both ends of the contact switch 180. The signal pins IO0 and IO1 of the contact switch 180 are respectively passed through the insulating sealing plugs 190 at both ends of the vacuum tube 170 to protect the signal pins at both ends of the contact switch 180 and play a role in fixing the contact switch 180 in the vacuum tube 170, providing high insulation performance to reduce leakage between the signal pins IO0 and IO1 at both ends of the contact switch 180 and surrounding conductive components (such as the coil 130, the housing, etc.). When contact switch 180 is closed, a conduction signal is input to and transmitted through contact switch 180. The difference between the input internal shield signal and the conduction signal is less than or equal to a preset value, minimizing the voltage difference between the internal shield signal and the conduction signal. The voltage difference between the two endpoints of contact switch 180 and internal shield layer 150 is also very small. Therefore, current from contact switch 180 no longer leaks directly to coil 130 and the external shield layer, thereby reducing leakage current from the switch within the relay. External insulating layer 120, intermediate insulating layer 140, and internal insulating layer 160 are made of insulating material.

[0038] In this embodiment, intermediate insulating layer 140 prevents current passing through contact switch 180 from flowing from internal insulating layer 160 to coil 130, thereby reducing leakage current between internal insulating layer 160 and coil 130. Because internal shielding layer 150 completely surrounds contact switch 180 and provides internal shielding layer 150 with an internal shielding signal whose difference from the on-state signal input to contact switch 180 is less than or equal to a preset value, the voltage difference between the two endpoints of contact switch 180 and internal shielding layer 150 is very small, preventing leakage current from contact switch 180 directly to coil 130 and external shielding layer 110. When contact switch 180 is connected, the voltage across internal shielding layer 150 is approximately equal to the voltage across the link between contact switch 180 within the relay. This means that the voltage difference between internal shielding layer 150 and contact switch 180 within the relay is very small, less than or equal to a preset value, thereby reducing leakage current from contact switch 180 within the relay. When the contact switch 180 is disconnected, because the internal shielding layer 150 is still connected to the internal shielding signal and the difference between the internal shielding signal and the conduction signal is less than or equal to the preset value, the voltage difference between the end of the contact switch 180 connected to the element providing the internal shielding signal and the internal shielding layer 150 will be very small, providing good leakage protection for the end of the contact switch 180 connected to the element providing the internal shielding signal.

[0039] It should be noted that the preset value refers to the signal loss caused by the transmission signal line or other devices during the signal transmission process. When the difference between the internal shielding signal and the conduction signal is less than or equal to the preset value, the internal shielding signal and the conduction signal can be approximately equal.

[0040] In some embodiments, there are K contact switches 180, each corresponding to an independent coil 130, intermediate insulating layer 140, inner shielding layer 150, and inner insulating layer 160. The K contact switches 180 share the outer shielding layer 110 and the outer insulating layer 120, where K is a positive integer. In this embodiment, each contact switch 180 corresponds to an independent coil 130, intermediate insulating layer 140, inner shielding layer 150, and inner insulating layer 160, providing good electromagnetic shielding and insulation protection for each contact switch 180. Even when the K contact switches 180 are integrated together, low leakage current can be ensured. Sharing the outer shielding layer 110 and the outer insulating layer 120 can reduce manufacturing costs.

[0041] In a specific embodiment, if Figures 9 to 12As shown, the first end of contact switch 180 is connected to a first external circuit, and the second end is connected to a second external circuit. The first external circuit outputs signal Signal0, and the second external circuit receives signal Signal1. The first external circuit is connected to the first end of contact switch 180 (i.e., contact switch signal pin IO0), and the second external circuit is connected to the second end of contact switch 180 (i.e., contact switch signal pin IO1) via signal Signal1. Coil 130 is connected to the control circuit, and external shielding layer 110 is connected to signal ground or device case ground. Specifically, external shielding layer signal pin Shield1 is connected to signal ground or device case ground.

[0042] In the first embodiment, see Figure 9 The internal shielding layer 150 is connected to the first external circuit. The internal shielding layer 150 is directly connected to the first external circuit. The first external circuit provides the internal shielding signal Guard to the internal shielding layer 150. The difference between the internal shielding signal Guard and the conduction signal Signal0 is less than or equal to the preset value. When the contact switch 180 is connected, the first external circuit also provides the conduction signal Signal0 to the contact switch 180. Since the resistance of the contact switch 180 is very small when it is turned on, the voltages at both ends of the contact switch 180 are approximately equal. Therefore, the voltage difference between the two ends of the contact switch 180 and the internal shielding layer 150 is very small. Therefore, the contact switch 180 The leakage current no longer directly flows to the coil and the external shielding layer. The internal shielding signal Guard protects the leakage current on the path of Signal0 passing through IO0 to the IO1 output, so that the leakage current when the contact switch 180 is on is very small. When the contact switch 180 is disconnected, the voltage at the first end of the contact switch 180 is approximately equal to the voltage of the internal shielding layer 150. The leakage current from the first end of the contact switch 180 to the internal shielding layer 150 is very small, so that the first end of the contact switch 180 is well protected from leakage current by the internal shielding signal inside the relay. In addition, this solution directly uses the first external circuit to provide leakage protection, reducing the additional protection voltage module and simplifying the circuit design.

[0043] In the second embodiment, see Figure 10The internal shielding layer 150 is connected to the first external circuit through the first protection voltage module, that is, the input of the first protection voltage module is connected to the first external circuit, the first protection voltage module tracks the voltage V0 of the conduction signal Signal0 output of the first external circuit, and outputs the internal shielding signal Guard. The voltage of the internal shielding signal Guard is approximately equal to the voltage V0 of the conduction signal Signal0. When the contact switch 180 is connected, since the resistance of the contact switch 180 is very small when it is turned on, the voltages at both ends of the contact switch 180 are approximately equal. Therefore, the two ends of the contact switch 180 are divided into Therefore, the contact switch 180 no longer leaks directly to the coil and the external shielding layer. The internal shielding signal Guard protects the leakage of Signal0 on the path from IO0 to IO1 output, making the leakage very small when the contact switch 180 is on. When the contact switch 180 is disconnected, the voltage at the first end of the contact switch 180 is approximately equal to the voltage of the internal shielding layer 150. The leakage from the first end of the contact switch 180 to the internal shielding layer 150 is very small, so that the first end of the contact switch 180 is well protected from leakage by the internal shielding signal inside the relay.

[0044] In the third embodiment, see Figure 11 , the internal shielding layer 150 is connected to the second external circuit, the internal shielding layer 150 is directly connected to the second external circuit, the second external circuit provides the internal shielding signal Guard to the internal shielding layer 150, the difference between which and the conduction signal Signal1 is less than or equal to the preset value, when the contact switch 180 is connected, the second external circuit will provide the conduction signal Signal1, because the resistance of the contact switch 180 is very small when it is turned on, the voltage at both ends of the contact switch 180 is approximately equal, therefore, the voltage difference between the two ends of the contact switch 180 and the internal shielding layer 150 is very small, so the contact switch 180 no longer directly leaks to the coil and the external The internal shielding layer is used as the shielding layer, and the internal shielding signal Guard protects the leakage current on the path of Signal0 (approximately equal to Signal1) passing through IO0 to reach IO1 output, so that the leakage current is very small when the contact switch 180 is turned off. When the contact switch 180 is disconnected, the voltage at the second end of the contact switch 180 is approximately equal to the voltage of the internal shielding layer 150, and the leakage current from the second end of the contact switch 180 to the internal shielding layer 150 is very small, so that the second end of the contact switch 180 is well protected from leakage current by the internal shielding signal inside the relay. In addition, this solution directly uses the second external circuit to provide leakage protection, reducing the additional protection voltage module and simplifying the circuit design.

[0045] In the fourth embodiment, see Figure 12, the internal shielding layer 150 is connected to the second external circuit through the second protection voltage module, that is, the input of the second protection voltage module is connected to the second external circuit, the second protection voltage module tracks the voltage V1 of the conduction signal Signal1 generated by the second protection voltage module, and outputs the internal shielding signal Guard, the internal shielding signal Guard voltage is approximately equal to the conduction signal Signal1 voltage V1, when the contact switch 180 is connected, since the resistance of the contact switch 180 is very small when it is turned on, the voltages at both ends of the contact switch 180 are approximately equal, therefore, the two ends of the contact switch 180 are connected to the internal shielding The voltage difference between the layers 150 is very small, so the contact switch 180 no longer leaks directly to the coil and the external shielding layer. The internal shielding signal Guard protects the leakage of Signal0 (approximately equal to Signal1) through IO0 to the IO1 output, so that the leakage current when on is very small; when the contact switch 180 is disconnected, the voltage at the second end of the contact switch 180 is approximately equal to the voltage of the internal shielding layer 150, and the leakage current from the second end of the contact switch 180 to the internal shielding layer 150 is very small, so that the second end of the contact switch 180 is well protected from leakage by the internal shielding signal inside the relay.

[0046] If low leakage is to be achieved, the leakage of the current of the sensitive signal in the link between the first external circuit and the second external circuit must be very small, and the first protection voltage module and the second protection voltage module also require input current. Therefore, in this solution, the first protection voltage module and the second protection voltage module can use devices with high input impedance and low input current, that is, the input voltage follows the output voltage, and the input current is isolated from the output current, ensuring that the leakage of the first protection voltage module and the second protection voltage module themselves is very small, further ensuring the effect of leakage protection.

[0047] In one embodiment, when the control circuit outputs a control signal and the voltage difference across the control coil 130 exceeds the threshold voltage for the contact switch 180 to operate, the contact switch 180 operates to a non-initial state; when the control circuit outputs a signal and the voltage difference across the control coil 130 is lower than the threshold voltage for the contact switch 180 to operate, the contact switch 180 returns to the initial state. The initial state includes disconnection or connection, and the non-initial state is a state different from the initial state. The threshold voltage is positive or negative, which depends on the electrical design of the relay coil 130 and the actuator of the contact switch 180. Figures 9 to 12As shown, the control circuit sends two signals, H and L, which are connected to the positive and negative signal pins Coil+ and Coil-, respectively, of coil 130. When the voltage difference between H and L exceeds the threshold voltage for contact switch 180 to operate, the relay switches to a non-initial state. When the voltage difference between H and L falls below the threshold voltage for switch operation, contact switch 180 returns to its initial state. For example, if the relay's initial state is with contact switch 180 open, the control circuit outputs a signal to control the voltage difference between Coil+ and Coil- to exceed the threshold voltage for relay coil 130 to operate, driving contact switch 180 to close and connect.

[0048] When Signal0 and Signal1 need to be connected, if the initial state of the relay is that the contact switch 180 is disconnected, the control circuit outputs a signal to control the pressure difference between Coil+ and Coil- to exceed the action threshold value of the coil 130, the relay coil 130 operates, and drives the contact switch 180 to close and connect; if the initial state of the relay is that the contact switch 180 is closed, the control circuit maintains the output signal to control the pressure difference between Coil+ and Coil- to be lower than the action threshold value of the relay coil 130, and the contact switch 180 remains in the initial closed (connected) state. When Signal0 and Signal1 need to be disconnected, if the initial state of the relay is that the contact switch 180 is disconnected, the control circuit outputs a signal to control the pressure difference between Coil+ and Coil- to be lower than the action threshold value of the relay coil 130, and the relay coil 130 operates, driving the contact switch 180 to disconnect; if the initial state of the relay is that the contact switch 180 is closed, the control circuit maintains the output signal to control the pressure difference between Coil+ and Coil- to be higher than the action threshold value of the coil 130, and the contact switch 180 remains in the initial closed (connected) state.

[0049] Figure 13 Schematic diagram of leakage current when the low leakage current relay of the present invention is connected, Figure 14 This is a schematic diagram of the leakage current of the low leakage current relay of the present invention when it is disconnected. Figure 13 and Figure 14 The signal pins IO0 and IO1 at both ends of the contact switch 180 are connected to the power supply and the load, respectively. Taking the V / I source input voltage V0 = 200V and the input current Iin = 10nA as an example, the output current is Iout and the output voltage is V1. The positive and negative signal pins Coil+ and Coil- of the coil are connected to the external control circuit, respectively. The voltages on the positive and negative signal pins of the coil are V(Coil+) and V(Coil-), respectively. The insulation resistances R10 and R11 between the two ends of the contact switch 180 and the internal shielding layer 150 are both equal to 1×10 13 Ω, when the contact switch 180 is disconnected, the insulation resistance Roff = 1×10 14Ω, when the contact switch 180 is connected, the insulation resistance Ron = 150mΩ. Since the resistance of the contact switch 180 is very small when it is turned on, the output voltage V1 = V0-Iin*Ron = V0-10nA*150mΩ = V0-1.5nV. Therefore, the output voltage V1 is approximately equal to the input voltage V0. The first protection voltage module is an operational amplifier, which works in the follower mode (gain equals 1). The voltage Vg of the operational amplifier is V0+ΔV0, ΔV0<3uV, and ΔV0 is the error of the operational amplifier (guaranteed by appropriate device selection and design).

[0050] See also Figure 13 When the low leakage relay is connected, the current IL00 leaked from the first end of the contact switch 180 to the internal shielding layer 150 is IL00 = (Vg-V0) / IR00 = ΔV0 / IR00 < (3uV) / 1×10 13 Ω=0.0003fA, the current IL01 from the second end of the contact switch 180 to the internal shielding layer 150=(Vg-V1) / IR01=ΔV0 / IR01<3uV / 1×10 13 Ω=0.0003fA. When the low leakage relay is connected, the total leakage current ILSWOn=IL00+IL01=0.0006fA. When connected, the leakage current level of a single relay increases by: 79.5pA / 0.0003fA=2.65×10 9 Because the internal shielding layer 150 is provided, and the voltage of the internal shielding layer 150 is approximately equal to the voltage of the link between the contact switch 180, that is, the voltage difference between the internal shielding layer 150 and the switch inside the relay is as small as possible, thereby reducing the leakage current of the contact switch 180 inside the relay.

[0051] See also Figure 14 When the low leakage relay is disconnected, the current IL00 leaking from the first end of the contact switch 180 to the internal shielding layer 150 is IL00 = (Vg-V0) / IR00 = ΔV0 / IR00 = (3uV) / 1×10 13 Ω=0.0003fA, leakage current IL02 between the two ends of contact switch 180=(V0-V1) / Roff=(200-0) / 1×10 14=2pA. When the low-leakage relay is open, the total leakage current ILSWOff = IL00 + IL02 = 2.0003pA. When the circuit is open, the leakage current of a single relay increases by 42pA / 2.0003pA = 21 times. When a single switch is open, internal shield layer 150 is still connected to the internal shield signal, so the first end of contact switch 180 (i.e., IO0) is well protected from leakage current by the internal shield signal within the relay. However, the voltage difference between the two ends of contact switch 180 (i.e., IO0 and IO1) is not controlled when the switch is open, so the signal on the IO0 side leaks to the IO1 side through Roff. In summary, the single-switch mode cannot completely solve the leakage problem in the open circuit scenario in high-voltage scenarios. Refer to the following topology for better leakage control.

[0052] See also Figure 15 The present invention also provides a single-circuit topology with low-leakage relays, including a first relay SW1, a second relay SW2, and a third relay SW3, each of which utilizes the low-leakage relays of the above-described embodiment. The first end of the contact switch 180 of the first relay SW1 is connected to a first external circuit, the second end of the contact switch 180 of the first relay SW1 is connected to the first end of the contact switch 180 of the second relay SW2, and the second end of the contact switch 180 of the second relay SW2 is connected to a second external circuit. An internal shielding signal is input to the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, and the internal shielding layer 150 of the third relay SW3, as well as the first end of the contact switch 180 of the third relay SW3. The second end of the contact switch 180 of the third relay SW3 is connected to the second end of the contact switch 180 of the first relay SW1. The second ends of all relays are simultaneously output or input. It should be noted that when the second end of the first relay and the second end of the second relay are both output ends, the first external circuit is the signal input end and the second external circuit is the signal output end; when the second end of the first relay and the second end of the second relay are both input ends, the first external circuit is the signal output end and the second external circuit is the signal input end.

[0053] In this embodiment, the first relay SW1, the second relay SW2, and the third relay SW3 form a T-type topology. When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected. Since the resistance of each relay contact switch 180 is very small when turned on, the first terminal voltage of the contact switch 180 of the first relay SW1, the second terminal voltage of the contact switch 180 of the first relay SW1, the first terminal voltage of the contact switch 180 of the second relay SW2, and the second terminal voltage of the contact switch 180 of the second relay SW2 are approximately equal. The first terminal voltage of the contact switch 180 of the first relay SW1 or the second terminal voltage of the contact switch 180 of the second relay SW2 is the conduction signal voltage, and the difference between the internal shielding signal and the conduction signal is less than or equal to the preset value. Therefore, the voltage of the internal shielding layer 150 of the first relay SW1, the voltage of the internal shielding layer 150 of the second relay SW2, and the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 are connected. The voltages of the first relay SW1 and the second relay SW2 are approximately equal, and thus, the leakage current from the contact switch 180 of the first relay SW1 to the internal shielding layer 150 of the first relay SW1 is very small, and the leakage current from the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is also very small. When the third relay SW3 is disconnected, the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the second end of the contact switch 180 of the first relay SW1, and the voltages across the contact switch 180 of the first relay SW1 are approximately equal. Therefore, the voltages across the contact switch 180 of the third relay SW3 are approximately equal. Because the difference between the internal shielding signal and the conduction signal is less than or equal to the preset value, the voltages across the contact switch 180 of the third relay SW3 are approximately equal to the voltage of the internal shielding layer 150 of the third relay SW3. Therefore, the leakage current from the contact switch 180 of the third relay SW3 to the internal shielding layer 150 of the third relay SW3 is very small. In summary, the total leakage current of the single-channel circuit topology when it is on is very small.When the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected. The voltage at the first end of the contact switch 180 of the third relay SW3 is approximately equal to the voltage at the first end of the contact switch 180 of the first relay SW1. The voltages across the contact switch 180 of the third relay SW3 are equal, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the second end of the contact switch 180 of the first relay SW1. Therefore, the voltages across the contact switch 180 of the first relay SW1 are approximately equal. Because the difference between the internal shielding signal and the conduction signal is less than or equal to a preset value, the voltage at the first end of the contact switch 180 of the first relay SW1 is approximately equal to the voltage of the internal shield layer 150 of the first relay SW1. Therefore, the leakage current from the first end of the contact switch 180 of the third relay SW3 to the internal shield layer 150 of the first relay SW1 is very small, effectively protecting the first end of the contact switch 180 of the first relay SW1 from leakage.

[0054] In some preferred embodiments, the conduction signal includes a first conduction signal and a second conduction signal, and the preset value includes a first preset value and a second preset value. The coil 130 of the first relay SW1, the coil 130 of the second relay SW2, and the coil 130 of the third relay SW3 are respectively connected to the control circuit, and the external shielding layer 110 of the first relay SW1, the external shielding layer 110 of the second relay SW2, and the external shielding layer 110 of the third relay SW3 are connected to the signal ground or the device case ground. The external shielding layers 110 of the first to third relays are respectively connected to the signal ground or the device case ground, or the external shielding layers 110 of the first to third relays are connected together and connected to the signal ground or the device case ground.

[0055] In a first specific embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the contact switch 180 of the third relay SW3 are connected to a first external circuit, and the first external circuit provides an internal shielding signal Guard to the internal shielding layer 150 of the first relay SW1. The difference between the internal shielding signal Guard and the first conduction signal provided by the first external circuit to the first end of the contact switch 180 of the first relay SW1 is less than or equal to a first preset value. When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected. Since the resistance of each relay contact switch 180 is very small when turned on, the first terminal voltage of the contact switch 180 of the first relay SW1 (i.e., the first conduction signal voltage), the second terminal voltage of the contact switch 180 of the first relay SW1, the first terminal voltage of the contact switch 180 of the second relay SW2, and the second terminal voltage of the contact switch 180 of the second relay SW2 are approximately equal, and the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value. Therefore, the voltage of the internal shielding layer 150 of the first relay SW1, the voltage of the internal shielding layer 150 of the second relay SW2 and the voltage of the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 are approximately equal. Furthermore, the contact switch 180 of the first relay SW1 sends a signal to the internal shielding layer of the first relay SW1. The leakage current of 150 is very small, and the leakage current from the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small; the third relay SW3 is disconnected, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the second end of the contact switch 180 of the first relay SW1, and the voltages across the contact switch 180 of the first relay SW1 are approximately equal. Therefore, the voltages across the contact switch 180 of the third relay SW3 are approximately equal. Because the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value, the voltages across the contact switch 180 of the third relay SW3 are approximately equal to the voltage of the internal shielding layer 150 of the third relay SW3. Furthermore, the leakage current from the contact switch 180 of the third relay SW3 to the internal shielding layer 150 of the third relay SW3 is very small. In summary, the total leakage current of the single-channel circuit topology when it is on is very small.When the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected. The voltage at the first end of the contact switch 180 of the third relay SW3 is approximately equal to the voltage at the first end of the contact switch 180 of the first relay SW1. The voltages across the contact switch 180 of the third relay SW3 are equal, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the second end of the contact switch 180 of the first relay SW1. Therefore, the voltages across the contact switch 180 of the first relay SW1 are approximately equal. Because the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value, the voltage at the first end of the contact switch 180 of the first relay SW1 is approximately equal to the voltage of the internal shield layer 150 of the first relay SW1. Therefore, the leakage current from the first end of the contact switch 180 of the first relay SW1 to the internal shield layer 150 of the first relay SW1 is very small, so that the first end of the contact switch 180 of the first relay SW1 is well protected from leakage current of the internal shielding signal.

[0056] In the second specific embodiment, see Figure 15The internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the contact switch 180 of the third relay SW3 are connected to the first external circuit through the first protection voltage module, and the first conduction signal is provided through the first external circuit, and the first external circuit provides an internal shielding signal through the first protection voltage module; the difference between the internal shielding signal and the first conduction signal provided by the first external circuit to the first end of the contact switch 180 of the first relay SW1 is less than or equal to the first preset value, the input of the first protection voltage module is connected to the first external circuit, and the output is the same as the first conduction signal. The shielding signal Guard, the internal shielding signal Guard voltage and the conduction signal Signal0 voltage V0 can be equal. The first protection voltage module provides the internal shielding signal Guard to the internal shielding layer 150 of the first relay SW1. When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected. Since the resistance of each relay contact switch 180 is very small when turned on, the first terminal voltage of the contact switch 180 of the first relay SW1 (i.e., the first conduction signal voltage), the second terminal voltage of the contact switch 180 of the first relay SW1, the first terminal voltage of the contact switch 180 of the second relay SW2, and the second terminal voltage of the contact switch 180 of the second relay SW2 are equal. The voltages are approximately equal, and the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value. Therefore, the voltage of the internal shielding layer 150 of the first relay SW1, the voltage of the internal shielding layer 150 of the second relay SW2, and the voltage of the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 are approximately equal. Furthermore, the leakage current from the contact switch 180 of the first relay SW1 to the internal shielding layer 150 of the first relay SW1 is very small, and the leakage current from the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small. The third relay SW3 is disconnected, and the contact switch 180 of the third relay SW3 is energized. The voltage at the second end of contact switch 180 is equal to the voltage at the second end of contact switch 180 of first relay SW1, and the voltages at both ends of contact switch 180 of first relay SW1 are approximately equal. Therefore, the voltages at both ends of contact switch 180 of third relay SW3 are approximately equal. Moreover, because the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value, the voltages at both ends of contact switch 180 of third relay SW3 are approximately equal to the voltage of internal shielding layer 150 of third relay SW3. Consequently, the leakage current from contact switch 180 of third relay SW3 to internal shielding layer 150 of third relay SW3 is very small. In summary, the total leakage current of the single-circuit topology when it is on is very small.When the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected. The voltage at the first end of the contact switch 180 of the third relay SW3 is approximately equal to the voltage at the first end of the contact switch 180 of the first relay SW1. The voltages across the contact switch 180 of the third relay SW3 are equal, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the second end of the contact switch 180 of the first relay SW1. Therefore, the voltages across the contact switch 180 of the first relay SW1 are approximately equal. Because the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value, the voltage at the first end of the contact switch 180 of the first relay SW1 is approximately equal to the voltage of the internal shield layer 150 of the first relay SW1. Therefore, the leakage current from the first end of the contact switch 180 of the first relay SW1 to the internal shield layer 150 of the first relay SW1 is very small, so that the first end of the contact switch 180 of the first relay SW1 is well protected from leakage current of the internal shielding signal.

[0057] In a third specific embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the contact switch 180 of the third relay SW3 are connected to a second external circuit, and a second conduction signal and an internal shielding signal are provided through the second external circuit; the second external circuit provides an internal shielding signal Guard to the internal shielding layer 150 of the second relay SW2, and the difference between the internal shielding signal and the second conduction signal provided to the first end of the contact switch 180 of the second relay SW2 is less than or equal to a second preset value. When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected. Since the resistance of each relay contact switch 180 is very small when turned on, the first end voltage of the contact switch 180 of the first relay SW1, the second end voltage of the contact switch 180 of the first relay SW1, the first end voltage of the contact switch 180 of the second relay SW2, and the second end voltage of the contact switch 180 of the second relay SW2 (i.e., the second conduction signal voltage) are approximately equal, and the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value. Therefore, the voltage of the internal shielding layer 150 of the first relay SW1, the voltage of the internal shielding layer 150 of the second relay SW2 and the voltage of the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 are approximately equal. Furthermore, the contact switch 180 of the first relay SW1 sends a signal to the internal shielding layer of the first relay SW1. The leakage current of 150 is very small, and the leakage current from the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small; the third relay SW3 is disconnected, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the first end of the contact switch 180 of the second relay SW2, and the voltages across the contact switch 180 of the second relay SW2 are approximately equal. Therefore, the voltages across the contact switch 180 of the third relay SW3 are approximately equal. Because the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value, the voltages across the contact switch 180 of the third relay SW3 are approximately equal to the voltage of the internal shielding layer 150 of the third relay SW3. Furthermore, the leakage current from the contact switch 180 of the third relay SW3 to the internal shielding layer 150 of the third relay SW3 is very small. In summary, the total leakage current of the single-channel circuit topology when it is on is very small.When the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected. The voltage at the first end of the contact switch 180 of the third relay SW3 is approximately equal to the voltage at the second end of the contact switch 180 of the second relay SW2. The voltages across the contact switch 180 of the third relay SW3 are equal, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the first end of the contact switch 180 of the second relay SW2. Therefore, the voltages across the contact switch 180 of the second relay SW2 are approximately equal. Because the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value, the voltage at the second end of the contact switch 180 of the second relay SW2 is approximately equal to the voltage of the internal shielding layer 150 of the second relay SW2. Therefore, the leakage current from the second end of the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small, so that the second end of the contact switch 180 of the second relay SW2 is well protected from leakage current of the internal shielding signal.

[0058] In a fourth specific embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the contact switch 180 of the third relay SW3 are connected to the second external circuit through a second protection voltage module, and a second conduction signal is provided through the second external circuit, and the second external circuit provides an internal shielding signal through the second protection voltage module, and the difference between the internal shielding signal and the second conduction signal provided to the first end of the contact switch 180 of the second relay SW2 is less than or equal to a second preset value. The input of the second protection voltage module is connected to the second external circuit, and outputs an internal shielding signal Guard that is the same as the conduction signal. The voltage of the internal shielding signal Guard can be equal to the voltage V1 of the conduction signal Signal1. The second protection voltage module provides the internal shielding signal Guard to the internal shielding layer 150 of the second relay SW2. When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected. Since the resistance of each relay contact switch 180 is very small when turned on, the first end voltage of the contact switch 180 of the first relay SW1, the second end voltage of the contact switch 180 of the first relay SW1, the first end voltage of the contact switch 180 of the second relay SW2, and the second end voltage of the contact switch 180 of the second relay SW2 (i.e., the second conduction signal voltage) are approximately equal, and the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value. Therefore, the voltage of the internal shielding layer 150 of the first relay SW1, the voltage of the internal shielding layer 150 of the second relay SW2, and the voltage of the contact switch 180 of the first relay SW1 and the second The voltage of the link between the contact switch 180 of the relay SW2 is approximately equal, and thus, the leakage current from the contact switch 180 of the first relay SW1 to the internal shielding layer 150 of the first relay SW1 is very small, and the leakage current from the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small; the third relay SW3 is disconnected, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the first end of the contact switch 180 of the second relay SW2, and the contact switch 180 of the second relay SW2 is equal to the voltage at the first end of the contact switch 180 of the second relay SW2. 0 is approximately equal, so the voltages across the contact switch 180 of the third relay SW3 are approximately equal. Since the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value, the voltages across the contact switch 180 of the third relay SW3 are approximately equal to the voltage of the internal shielding layer 150 of the third relay SW3. Furthermore, the leakage current from the contact switch 180 of the third relay SW3 to the internal shielding layer 150 of the third relay SW3 is very small. In summary, the total leakage current of the single-circuit topology when it is on is very small.When the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected. The voltage at the first end of the contact switch 180 of the third relay SW3 is approximately equal to the voltage at the second end of the contact switch 180 of the second relay SW2. The voltages across the contact switch 180 of the third relay SW3 are equal, and the voltage at the second end of the contact switch 180 of the third relay SW3 is equal to the voltage at the first end of the contact switch 180 of the second relay SW2. Therefore, the voltages across the contact switch 180 of the second relay SW2 are approximately equal. Because the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value, the voltage at the second end of the contact switch 180 of the second relay SW2 is approximately equal to the voltage of the internal shielding layer 150 of the second relay SW2. Therefore, the leakage current from the second end of the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2 is very small, so that the second end of the contact switch 180 of the second relay SW2 is well protected from leakage current of the internal shielding signal.

[0059] It should be noted that the first preset value and the second preset value refer to the amount of signal loss caused by the transmission signal line or other devices during the signal transmission process, and since the signal transmission can use the same signal line or device or different signal lines or devices, the first preset value and the second preset value can be the same or different. Therefore, when the difference between the internal shielding signal and the first conduction signal is less than or equal to the first preset value, the internal shielding signal and the first conduction signal can be approximately equal, and when the difference between the internal shielding signal and the second conduction signal is less than or equal to the second preset value, the internal shielding signal and the second conduction signal can be approximately equal. In this solution, the voltage being approximately equal includes the voltage being equal, or the difference between the voltage values ​​being within a preset range.

[0060] See also Figure 15 The control circuit sends four signals, H0, H1, H2, and L. Signal H0 is input to the positive coil signal pin Coil+ of the first relay SW1, signal H1 is input to the positive coil signal pin Coil+ of the second relay SW2, signal H2 is input to the positive coil signal pin Coil+ of the third relay SW3, and signal L is input to the negative coil signal pins Coil- of the first through third relays, respectively. When the voltage difference between Hx (X=0, 1, 2) and L exceeds the threshold voltage for contact switch 180 to operate, the corresponding relay SWx (X=0, 1, 2) operates to a non-initial state. When the voltage difference between Hx (X=0, 1, 2) and L falls below the threshold voltage for contact switch 180 to operate, the corresponding SWx (X=0, 1, 2) contact switch 180 returns to its initial state.

[0061] In one embodiment, see Figure 16When the single-circuit topology is connected, the first relay SW1 and the second relay SW2 are connected, and the third relay SW3 is disconnected; when the single-circuit topology is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected.

[0062] See also Figure 16 , the first single-circuit topology shows the initial state, the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 is disconnected, the link between the contact switch 180 of the third relay SW3 is connected, the first relay SW1 is disconnected, the second relay SW2 is disconnected, and the third relay SW3 is connected; the second single-circuit topology shows the connected state, the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 is connected, the link between the contact switch 180 of the third relay SW3 is disconnected, the first relay SW1 is connected, the second relay SW2 is connected, and the third relay SW3 is disconnected; the third single-circuit topology shows the disconnected state, the link between the contact switch 180 of the first relay SW1 and the contact switch 180 of the second relay SW2 is disconnected, the link between the contact switch 180 of the third relay SW3 is connected, the first relay SW1 is disconnected, the second relay SW2 is disconnected, and the third relay SW3 is connected.

[0063] In another embodiment, the first relay SW1, the second relay SW2, and the third relay SW3 can be independent relays or integrated together to form a relay structure. For example, the three relays are packaged together, and the control signals H0, H1, and H2 are not limited to sampling linkage control mode. The integrated relay structure does not require a separate control signal for each relay, but can control all relays through a unified control signal, reducing the number and complexity of control signals. The integrated relay structure makes the circuit more compact and takes up less space, making it suitable for miniaturized equipment and space-limited application scenarios. Independent relays facilitate circuit design and modification, and the position and connection method of each relay can be flexibly configured according to actual needs.

[0064] In one embodiment, the first and second protection voltage modules include operational amplifiers or circuits that provide internal shielding signals. The operational amplifiers can provide a high-precision signal following function. In follower mode (gain of 1), the operational amplifiers can accurately replicate the input voltage to the output, ensuring that the shielding signal voltage is approximately equal to the conduction signal voltage, thereby effectively reducing leakage current across the contact switch 180. The operational amplifiers have high input impedance and low output impedance.

[0065] See also Figure 16 and Figure 17, the controlled signal is connected to the first end of the first relay SW1 (abbreviated as end A), the load is connected to the second end of the second relay SW2 (abbreviated as end B), and the first end of the third relay SW3 (abbreviated as end G) is connected to the first protection voltage module. The connectivity state of the T-type single-channel circuit topology: the first relay SW1 is connected, the second relay SW2 is connected, and the third relay SW3 is disconnected. The voltage of the internal shielding layer 150 of the first relay SW1 and the voltage of the internal shielding layer 150 of the second relay SW2 are taken from the voltage of end A, so the voltage of the internal shielding layer 150 of the three relays is equal to the voltage of end A. Since the on-resistance of each of the three relays is very small, in the low current scenario, the voltage of end B is approximately equal to the voltage of the second end of the first relay SW1 (abbreviated as end D), and the voltage of point D is approximately equal to the voltage of end A. It can be seen that in the path between ends A and B, the voltage difference between the sensitive signal and the internal shielding layer 150 is very small (uV level), and the insulation resistance between the contact switch 180 of each relay and the internal shielding layer 150 can be achieved to 1×10 13 Ω, so it can be obtained that the leakage current between the AB path and its corresponding internal shielding layer 150 is much less than the 1fA level. The third relay SW3 is disconnected, and the voltage at the second terminal IO1 of the third relay SW3 is equal to the voltage at point D, while the voltage at terminal G is approximately equal to the voltage at terminal A. According to the above analysis, the voltage at point D is approximately equal to the voltage at terminal A. Therefore, the voltage difference between IO0 and IO1 of the third relay SW3 is also at the uV level, and the relay Roff is 1×10 14 Ω, so the leakage current through Roff of the third relay SW3 is also far less than 1fA. The voltage difference between the IO1 port of the third relay SW3 and the voltage of its internal shield layer 150 is also in the uV range, so the current leaking from IO1 of the third relay SW3 to the internal shield layer 150 is also far less than 1fA. The above shows that the leakage current of the T-type topology switch when it is on is very small.

[0066] See also Figure 16 and Figure 18The function of the third relay SW3 is to disconnect the first and second relays SW1 and SW2 of the T-type single-circuit topology, while closing the third relay SW3. At this time, the internal shielding signal Guard is connected to the second terminal of the first relay SW1 (referred to as the D terminal) to prevent leakage current when the T-type topology switch is disconnected. The T-type topology switch provides excellent leakage protection when disconnected between terminals A and B. When the first and second relays SW1 and SW2 of the T-type topology switch are disconnected, the closing of the third relay SW3 ensures that the voltage at terminal G is approximately equal to the voltage at terminal A. Because the closing of the third relay SW3 connects the first terminal IO0 and the second terminal IO1 of the third relay SW3, the voltage at terminal D is equal to the voltage at terminal G of the third relay SW3. Since the voltage at terminal G is equal to the voltage at terminal A, the voltage at terminal G is approximately equal to the voltage at terminal A, with a voltage difference of μV. When the AB path of the T-type relay topology is disconnected, the leakage current to the A terminal is contributed by the first terminal IO0 of the first relay SW1. The voltage of the first terminal IO0 of the first relay SW1 is the voltage of the A terminal. The voltage of the internal shielding layer 150 of the first relay SW1 is equal to the voltage of the G terminal. Therefore, the voltage difference between the first terminal IO0 of the first relay SW1 and its internal shielding layer 150 is also at the uV level. Its insulation resistance is greater than 1×10 13 Ω, so the leakage current from the first terminal IO0 of the first relay SW1 to the internal shielding layer 150 is much less than 1fA. The operational amplifier OPA0 also contributes leakage current to terminal A, but this case requires that the input current of the operational amplifier OPA0 or a circuit similar to the operational amplifier be at the fA level; therefore, when the T-type topology is disconnected, the present invention effectively protects the leakage current at terminal A. The principles of leakage protection for terminal A are provided herein by providing an internal shielding signal through an operational amplifier connected to a first external circuit. Leakage protection for terminal A can also be achieved by directly providing an internal shielding signal through the first external circuit. Leakage protection for terminal B can also be achieved by providing an internal shielding signal through a second protection voltage module (e.g., an operational amplifier) ​​connected to a second external circuit. Leakage protection for terminal B can also be achieved by directly providing an internal shielding signal through the second external circuit. The principles of leakage protection for these schemes are similar and will not be repeated here.

[0067] Combine Figure 15 ,The workflow of a single circuit topology is explained below.

[0068] The control circuit sends a control signal to switch the single-circuit topology from an initial state to a connected state;

[0069] When all relays in the single-circuit topology are switched to a predetermined connection state according to the control requirements, the signal link between the first external circuit and the second external circuit is connected, and the link between the G terminal and the D terminal is disconnected;

[0070] The first protection driving module follows the change of the voltage V0 of the first external circuit output signal Signal0 in real time and outputs an internal shielding signal guard equal to the voltage of V0. The internal shielding signal guard is connected to the inside of the single-channel circuit topology through the G terminal to provide leakage protection for the sensitive signals at the A and B terminals.

[0071] After all circuit states of the first external circuit and the second external circuit are stable and the signals are stable, high-precision output and measurement can be started;

[0072] When the single-circuit topology is required to disconnect the link between the first external circuit and the second external circuit, the control circuit controls the single-circuit topology to return to the disconnected state TSWoff, ie, the initial state.

[0073] See also Figure 19 The present invention also provides a multi-circuit topology with a low-leakage relay, including the low-leakage relay in the above embodiment, and the multi-circuit topology includes n single-circuit topologies such as the above embodiment, the first end of the contact switch 180 of the first relay SW1 in the n single-circuit topologies is connected to a first external circuit, the second external circuits are n and correspond one-to-one to the n single-circuit topologies, and the second external circuits are connected to the second end of the contact switch 180 of the second relay SW2 of the corresponding single-circuit topology, wherein n is a positive integer greater than 1.

[0074] In this embodiment, in a connected branch in a multi-way circuit topology, an internal shielding signal is provided for the contact switch 180 of the first relay SW1 in the connected branch to the internal shielding layer 150 of the first relay SW1 and for the contact switch 180 of the second relay SW2 to the internal shielding layer 150 of the second relay SW2, so as to provide leakage protection for the first end and the second end of the contact switch of the first relay SW1 in the connected branch; in a disconnected branch in the multi-way circuit topology, the voltages at both ends of the contact switch 180 of the first relay SW1 are approximately equal, so that the leakage current at the first end of the contact switch 180 of the first relay SW1 in the disconnected branch is very small.

[0075] In a first possible embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the third relay SW3 in all single-circuit topologies are connected to the first external circuit. By setting the first end of the contact switch 180 of the first relay SW1 in all branches, leakage protection is provided for the link between the first end of the contact switch 180 of the first relay SW1 on all connected branches and the second end of the contact switch 180 of the second relay SW2 through the first external circuit. At the same time, the first external circuit can also provide leakage protection for the first end of the contact switch 180 of the first relay SW1 on all disconnected branches.

[0076] In a second possible embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3, and the first end of the third relay SW3 in all single-circuit topologies are connected to the first external circuit through the first protection voltage module, such as Figure 19 As shown, the first external circuit A1 outputs a signal SourceBus0 and inputs it to the A terminals of all branches. The signal SourceBus0 is then input to the first protection voltage module LG0. The first protection voltage module LG0 outputs a signal LG0 with the same voltage as the input. This output signal LG0 is then input to the G terminals of all branches. The second external circuit Bx is connected to the B terminals of the corresponding branch TSWx via LoadBusx (x = 1 to n). By providing a first protection voltage module at the first terminal of the contact switch 180 of the first relay SW1 in all branches, leakage protection is provided for the link between the first terminal of the contact switch 180 of the first relay SW1 and the second terminal of the contact switch 180 of the second relay SW2 in all connected branches. Simultaneously, the first external circuit can also provide leakage protection for the first terminal of the contact switch 180 of the first relay SW1 in all disconnected branches.

[0077] In a third possible embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3 and the first end of the third relay SW3 in each single-circuit topology are respectively connected to the second external circuit of the corresponding branch, and a second external circuit is separately set for the second end of the contact switch 180 of the second relay SW2 of each branch. For a connected branch, leakage protection is provided for the link between the first end of the contact switch 180 of the first relay SW1 and the second end of the contact switch 180 of the second relay SW2 on the connected branch through the second external circuit on the connected branch; for a disconnected branch, leakage protection is provided for the second end of the contact switch 180 of the second relay SW2 on the disconnected branch.

[0078] In a fourth possible embodiment, the internal shielding layer 150 of the first relay SW1, the internal shielding layer 150 of the second relay SW2, the internal shielding layer 150 of the third relay SW3 and the first end of the third relay SW3 in each single-circuit topology are connected to the second external circuit of the corresponding branch through a second protection voltage module, and a second protection voltage module is separately provided for the second end of the contact switch 180 of the second relay SW2 of each branch. For a connected branch, leakage protection is provided for the link between the first end of the contact switch 180 of the first relay SW1 and the second end of the contact switch 180 of the second relay SW2 on the connected branch through the second protection voltage module on the connected branch; for a disconnected branch, leakage protection is provided for the second end of the contact switch 180 of the second relay SW2 on the disconnected branch through the second protection voltage module on the disconnected branch.

[0079] See also Figure 19 , one port drives a multi-port load, with the left end connected to the source and each right end connected to a load. TSW1, TSW2, ..., TSWn are the basic switch topology for each branch. The output voltage signal of the V / I_0 signal source is recorded as SourceBus0. SourceBus0 is input to the A terminals of all branches. The B terminals of each branch are connected to their own independent loads. OPA_L0 is an operational amplifier operating in follower mode (gain of 1). The input of OPA_L0 is the signal SourceBus0, and the output signal LG0 of OPA_L0 is input to the G terminals of all branches. The figure shows an example of selecting one from multiple channels. In fact, the present invention is not limited to the scenario where multiple loads are connected simultaneously.

[0080] In this example of multiple-way selection, TSW1 is open and the other branches are open (this is not a limitation of the present invention, but merely an example). Based on the previously described leakage current calculation results for the single-way circuit topology, the leakage current when the TSW branch is open is: ILTSWon = 0.00153fA; the leakage current when the TSW branch is open is: ILTSWoff = 0.00033fA. In a multi-way circuit topology, the leakage current when one branch is connected is: Ileakage = ILTSWon + (N-1) * ILTSWoff; the leakage current when X branches are connected is: Ileakage = X * ILTSWon + (NX) * ILTSWoff, where 0 ≤ X ≤ N. If N-1 = 50, the leakage current when only one branch is connected is: Ileakage = ILTSWon + 50 * ILTSWoff = 0.01803fA. Compared with the leakage current of 2.1795nA in the circuit topology using a single relay, the leakage current of the invented multi-channel circuit topology is improved by: 2.1795nA / 0.01803fA=1.2×10 8 times.

[0081] In one embodiment, see Figure 20 , when the multi-circuit topology is connected, the first external circuit is connected to the second external circuit through at least one single-circuit topology in a connected state, and the single-circuit topologies of the remaining branches are in a disconnected state; see Figure 21 When the multi-circuit topology is disconnected, all single-circuit topologies are disconnected. In this multi-circuit topology, all branches can be disconnected, disconnecting the first external circuit A1 from all second external circuits Bx (x=1-n). Alternatively, any branch TSWx can be opened, with the first external circuit A1 connected to only one of the second external circuits Bx (connected branches with x=1-n). Alternatively, any number of branches TSWx can be opened, with the first external circuit A1 connected to multiple second external circuits Bx (connected branches with x=1-n) through these opened branches. The specific functions of the first external circuit A1 and the second external circuit Bx depend on the actual application, and their combined function is achieved through branch connection.

[0082] In the connected branch, the first relay SW1 and the second relay SW2 are connected, and the third relay SW3 is disconnected. Since the voltage of signal LG0 is equal to the voltage of SourceBus0, LG0 provides low leakage protection from contact switch 180 to internal shield 150 for the first and second relays SW1 and SW2 in the connected branch. Since the on-resistance of each relay switch is very low (typically less than 150 milliohms), when the current transmitting the signal from terminal A to terminal B in the branch is less than 10uA, the DC voltage drop from terminal A to terminal D of the first relay SW1 in the connected branch is less than 10uA * 150mA = 1.5uV. From the leakage current analysis of the connected single-circuit topology, it can be seen that the voltage at terminal A is approximately equal to the voltage at terminal G. Therefore, the voltage difference between terminals D and G in the connected branch is also less than 1.5uV. Therefore, the third relay SW3 in the connected branch is disconnected in the connected branch. The small voltage difference between terminals D and G ensures that the current leaking from terminal D to terminal G is very small. From the above, it can be seen that the connecting branch achieves ultra-low leakage from end A to end B.

[0083] When the branch is disconnected, the first relay SW1 and the second relay SW2 are disconnected, and the third relay SW3 is connected: because the third relay SW3 is connected, the voltages at both ends of the third relay SW3 are equal, and the voltage at the second end of the third relay SW3 is equal to the voltage at the D end, and the voltage at the first end of the third relay SW3 is approximately equal to the voltage at the A end, so the voltages at both ends of the contact switch 180 of the first relay SW1 that disconnects the branch are approximately equal, and because the voltage at the A end is the voltage of LG0, and the voltage of LG0 is equal to SourceBus0, even though SourceBus0 is connected to the A ends of all branches, the above-mentioned characteristics of the disconnected branch ensure that the leakage current of SourceBus0 at the A end of the disconnected branch is also very small.

[0084] In summary, in a multi-circuit topology, the present invention successfully solves the leakage problem of the switching topology network, ensuring that the signal of the second external circuit Bx (the connecting branch in x=1~n) connected to the first external circuit A1 through the connecting branch has very low leakage when passing through the switch matrix, and makes the leakage of SourceBus0 at the A-end branch also very small, thereby realizing the ultra-low leakage transmission of electrical signals between the first external circuit A1 and the second external circuit Bx (x=1~n).

[0085] The following explains the workflow of the multi-channel circuit topology.

[0086] See also Figure 21 , the control circuit sends a control signal to control the disconnection state of all TSWx (x=1~n);

[0087] See also Figure 20According to application requirements, the control circuit sends a control signal to control the branch TSWx that needs to be connected (multiple branches can be connected at the same time) to be connected, thereby realizing the signal connection between the first external circuit A1 and the second external circuit Bx;

[0088] After the connected branch circuit is stable, the first external circuit A1 and the second external circuit Bx are turned on and started;

[0089] The first protection voltage module LG0 detects the voltage of SourceBus0 in real time and outputs an LG0 signal of equal voltage;

[0090] When the signal between the first external circuit A1 and the second external circuit Bx stabilizes, the voltage of LG0 also stabilizes synchronously. At this time, the multi-path switching topology is in a low leakage current state. The application can then perform precise signal transmission and measurement between the first external circuit A1 and the second external circuit Bx.

[0091] Although embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the invention as set forth in the appended claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways. Unless otherwise defined, technical or scientific terms used herein shall have the same ordinary meaning as would be understood by a person of ordinary skill in the art to which this invention pertains.

Claims

1. A low leakage current relay, characterized in that: include: External shielding layer, external insulating layer, coil, intermediate insulating layer, internal shielding layer, internal insulating layer, switch accommodating cavity and contact switch; An external shielding signal is input into the external shielding layer, and the external shielding layer provides electrical shielding for an internal circuit of the low leakage current relay through the external shielding signal; The external insulating layer is provided between the external shielding layer and the coil, and is used to isolate the coil from the external shielding layer; The coil is arranged between the outer insulating layer and the middle insulating layer, and the coil controls the on and off of the contact switch through an input control signal; The intermediate insulating layer is provided between the coil and the internal shielding layer, and is used to isolate the coil from the internal shielding layer; The internal shielding layer is provided between the intermediate insulating layer and the internal insulating layer, and the internal shielding signal is input into the internal shielding layer; The internal insulating layer is provided between the internal shielding layer and the switch accommodating cavity, and is used to protect the switch accommodating cavity and isolate the internal shielding layer from the contact switch; The switch accommodating cavity is used to accommodate the contact switch and to provide insulation between the contact switch and the coil and between the contact switch and the housing; When the contact switch is closed, a conduction signal is input into the contact switch and transmitted through the contact switch, and a difference between the input internal shielding signal and the conduction signal is less than or equal to a preset value.

2. The low leakage current relay according to claim 1, characterized in that: There are K contact switches, each of which corresponds to an independent coil, the intermediate insulating layer, the inner shielding layer, and the inner insulating layer. The K contact switches share the outer shielding layer and the outer insulating layer, and K is a positive integer.

3. The low leakage current relay according to claim 1, characterized in that: The first end of the contact switch is connected to the first external circuit and the second end is connected to the second external circuit; The internal shielding layer is connected to the first external circuit, or the internal shielding layer is connected to the first external circuit through a first protection voltage module, or the internal shielding layer is connected to the second external circuit, or the internal shielding layer is connected to the second external circuit through a second protection voltage module; The coil is connected to the control circuit, and the external shielding layer is connected to the signal ground or the device shell ground.

4. The low leakage current relay according to claim 3, characterized in that: When the control circuit outputs a control signal to control the voltage difference across the coil to exceed the threshold voltage for the contact switch to operate, the contact switch operates to a non-initial state; When the control circuit output signal controls the voltage difference across the coil to be lower than the threshold voltage for the contact switch to operate, the contact switch returns to an initial state, where the initial state includes disconnection or connection, and the non-initial state is a state different from the initial state, where the threshold voltage is positive or negative.

5. A single circuit topology with a low leakage current relay, characterized in that: comprising a first relay, a second relay, and a third relay using the low leakage current relay according to claim 1 or 2; The first end of the contact switch of the first relay is connected to the first external circuit, the second end of the contact switch of the first relay is connected to the first end of the contact switch of the second relay, and the second end of the contact switch of the second relay is connected to the second external circuit; The internal shielding signal is input into the internal shielding layer of the first relay, the internal shielding layer of the second relay, the internal shielding layer of the third relay and the first end of the contact switch of the third relay. The second end of the contact switch of the third relay is connected to the second end of the contact switch of the first relay. The second end of the first relay and the second end of the second relay are both output ends or input ends.

6. The single-circuit topology with a low leakage current relay according to claim 5, characterized in that: The conduction signal includes a first conduction signal and a second conduction signal, and the preset value includes a first preset value and a second preset value; The internal shielding layer of the first relay, the internal shielding layer of the second relay, the internal shielding layer of the third relay, and the first end of the contact switch of the third relay are connected to the first external circuit, and the first conduction signal and the internal shielding signal are provided through the first external circuit; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, the internal shielding layer of the third relay, and the first end of the contact switch of the third relay are connected to the first external circuit through a first protection voltage module, and the first conduction signal is provided through the first external circuit, and the first external circuit provides the internal shielding signal through the first protection voltage module; the difference between the internal shielding signal and the first conduction signal provided to the first end of the contact switch of the first relay is less than or equal to the first preset value; or, The internal shielding layer of the first relay, the internal shielding layer of the second relay, the internal shielding layer of the third relay, and the first end of the contact switch of the third relay are connected to the second external circuit, and the second conduction signal and the internal shielding signal are provided through the second external circuit; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, the internal shielding layer of the third relay, and the first end of the contact switch of the third relay are connected to the second external circuit through a second protection voltage module, and the second conduction signal is provided through the second external circuit, and the second external circuit provides the internal shielding signal through the second protection voltage module, and the difference between the internal shielding signal and the second conduction signal provided to the first end of the contact switch of the second relay is less than or equal to the second preset value; The coil of the first relay, the coil of the second relay, and the coil of the third relay are respectively connected to the control circuit, and the external shielding layer of the first relay, the external shielding layer of the second relay, and the external shielding layer of the third relay are connected to the signal ground or the device shell ground.

7. The single-circuit topology with a low leakage current relay according to claim 6, characterized in that: When the single-circuit topology is connected, the first relay and the second relay are connected, and the third relay is disconnected; When the single-circuit topology is disconnected, the first relay and the second relay are disconnected, and the third relay is connected.

8. The single-circuit topology with a low leakage current relay according to claim 6, characterized in that: The first relay, the second relay, and the third relay may be independent relays or integrated together to form a relay structure.

9. The single-circuit topology with a low leakage current relay according to claim 6, characterized in that: The first protection voltage module and the second protection voltage module include an operational amplifier or a circuit providing the internal shielding signal.

10. A multi-circuit topology with low leakage current relays, characterized in that: The invention comprises a low leakage current relay according to claim 1 or 2, wherein the multi-circuit topology comprises n single-circuit topologies according to any one of claims 5 to 9, The first end of the contact switch of the first relay in the n single-circuit topologies is connected to a first external circuit, there are n second external circuits and they correspond one-to-one to the n single-circuit topologies, and the second external circuit is connected to the second end of the contact switch of the second relay of the corresponding single-circuit topology, where n is a positive integer greater than 1.

11. The multi-circuit topology with low leakage relays according to claim 10, characterized in that: The internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in all the single-circuit topologies are connected to the first external circuit; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in all the single-circuit topologies are connected to the first external circuit through the first protection voltage module; or, The internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in each single-circuit topology are respectively connected to the second external circuit of the corresponding branch; or, the internal shielding layer of the first relay, the internal shielding layer of the second relay, and the internal shielding layer of the third relay in each single-circuit topology are connected to the second external circuit of the corresponding branch through a second protection voltage module.

12. The multi-circuit topology with low leakage relays according to claim 10, characterized in that: When the multi-circuit topology is connected, the first external circuit is connected to the second external circuit through at least one of the single-circuit topologies in a connected state, and the single-circuit topologies of the remaining branches are in a disconnected state; When the multi-way circuit topology is disconnected, all the single-way circuit topologies are in a disconnected state.

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