Electronic circuits for electrochemical gas sensors

Abstract

Various embodiments disclose an electronic circuit for an electrochemical gas sensor. The electronic circuit includes a first switching element electrically coupled to a reference terminal and a ground voltage terminal of the electrochemical gas sensor. In addition, the electronic circuit includes a second switching element electrically coupled to a sensing terminal and a ground voltage terminal of the electrochemical gas sensor. In an instance in which the electrochemical gas sensor is powered off, the first switching element and the second switching element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal, so that when the sensing electrode and the target gas react while the electrochemical gas sensor is powered off, the current generated flows to the ground voltage terminal and the potential of the reference terminal and the sensing terminal remain equal.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to electrochemical gas sensors, and more particularly to electronic circuits for electrochemical gas sensors. Background Art

[0002] Conventional electrochemical gas sensors typically include a reference electrode and a sensing electrode in contact with an electrolyte. In operation, the sensing electrode can be coupled to a control and measurement circuit and a voltage source (e.g., a battery), which can be configured to apply a predefined bias voltage to the sensing electrode relative to the reference electrode. When the sensing electrode contacts the gas to be detected, for example, when the gas diffuses in the electrochemical gas sensor, the gas reacts with the sensing electrode, which generates a current at the sensing electrode. The magnitude of the generated current can indicate the gas concentration detected by the electrochemical gas sensor.

[0003] Applicants have identified a number of deficiencies and problems associated with conventional electronic circuits for electrochemical gas sensors. Through applied effort, ingenuity, and innovation, many of these identified problems have been solved by developing solutions included in the embodiments of the present disclosure, many examples of which are described in detail herein. Summary of the invention

[0004] Various embodiments illustrated herein disclose an electronic circuit for an electrochemical gas sensor, comprising a first switching element electrically coupled to a reference terminal of the electrochemical gas sensor. The electronic circuit may also include a second switching element electrically coupled to a sensing terminal of the electrochemical gas sensor. In an instance where the electrochemical gas sensor is powered off, the first switching element and the second switching element may be configured to electrically couple the reference terminal and the sensing terminal to the same potential.

[0005] Various embodiments illustrated herein disclose a sensing system including an electrochemical gas sensor including a reference electrode and a sensing electrode. In some embodiments, the electrochemical gas sensor is electrically coupled to a voltage source. In addition, in some embodiments, the sensing system may include a first transistor including a first terminal electrically coupled to the reference electrode, a second terminal electrically coupled to a ground voltage terminal, and a gate terminal electrically coupled to the ground voltage terminal and to the voltage source. In some embodiments, the sensing system may include a second transistor including a first terminal electrically coupled to the sensing electrode, a second terminal electrically coupled to the ground voltage terminal, and a gate terminal electrically coupled to the ground voltage terminal and to the voltage source. In some embodiments, in an instance in which the electrochemical gas sensor is powered off, the gate terminals of the first transistor and the second transistor may be grounded, causing the reference electrode and the sensing electrode of the electrochemical gas sensor to be connected to the ground voltage terminal through the first transistor and the second transistor, respectively.

[0006] In some embodiments, the first terminal of the first transistor may be referred to as a "first terminal", the second terminal of the first transistor may be referred to as a "second terminal", the gate terminal of the first transistor may be referred to as a "first gate terminal", the first terminal of the second transistor may be referred to as a "third terminal", the second terminal of the second transistor may be referred to as a "fourth terminal", and the gate terminal of the second transistor may be referred to as a "second gate terminal".

[0007] Thus, in some embodiments, the electronic circuit may be configured to operate at least a portion of the functions of the electrochemical gas sensor. In some embodiments, the electrochemical gas sensor may include a reference electrode and a sensing electrode, the sensing electrode being configured to react with the target gas to generate an electric current. In some embodiments, the electronic circuit may include at least a first switching element and a second switching element. In some embodiments, the first switching element may be electrically coupled to a reference terminal and a ground voltage terminal of the electrochemical gas sensor. In some embodiments, the second switching element may be electrically coupled to a sensing terminal and a ground voltage terminal of the electrochemical gas sensor. In some embodiments, the first switching element and the second switching element may be configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal in an instance in which the electrochemical gas sensor is powered off, so that the current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered off flows to the ground voltage terminal and the potential at the reference terminal and the potential at the sensing terminal remain equal.

[0008] In some embodiments, the first switch element and the second switch element can be configured to ground a reference electrode and a sensing electrode of the electrochemical gas sensor to a ground voltage terminal via the reference terminal and the sensing terminal, respectively, in an instance in which the electrochemical gas sensor is powered off. In some embodiments, the first switch element corresponds to a first transistor, and the second switch element corresponds to a second transistor. In some embodiments, the first transistor may include a first terminal electrically coupled to the ground voltage terminal, and a second terminal electrically coupled to the reference terminal of the electrochemical gas sensor. In some embodiments, the second transistor may include a third terminal electrically coupled to the ground voltage terminal, and a fourth terminal electrically coupled to the sensing terminal of the electrochemical gas sensor.

[0009] In some embodiments, the first terminal and the third terminal may correspond to the drain terminal, and the second terminal and the fourth terminal may correspond to the source terminal. In some embodiments, the first terminal and the third terminal may correspond to the source terminal, and the second terminal and the fourth terminal may correspond to the drain terminal. In some embodiments, the first transistor may include a first gate terminal, and the second transistor may include a second gate terminal. In some embodiments, the first gate terminal may be electrically coupled to the second gate terminal, the voltage source, and the ground voltage terminal. In an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal may be grounded, causing the first terminal and the third terminal to be shorted to the second terminal and the fourth terminal, respectively. In an instance in which the electrochemical gas sensor is powered on, the voltage source may be caused to apply at least a cutoff voltage to the first gate terminal and the second gate terminal, causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively.

[0010] In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to a voltage source through a diode, the diode being configured to cause a delay in the electrical coupling of the first gate terminal and the second gate terminal to the voltage source to prevent damage to the electrochemical gas sensor when the electrochemical gas sensor is powered on. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a resistive element. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to a ground voltage terminal through a capacitive element. In some embodiments, the first terminal and the third terminal may also be coupled to a voltage source, so that in an instance in which the electrochemical gas sensor is powered on, the voltage source applies a bias voltage at the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor, respectively, when the electrochemical gas sensor is powered on, and in an instance in which the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded. In some embodiments, the sensing terminal of the electrochemical gas sensor may be electrically coupled to a sensing electrode in the electrochemical gas sensor, and the reference terminal of the electrochemical gas sensor may be electrically coupled to a reference electrode in the electrochemical gas sensor.

[0011] According to some embodiments, a device for sensing a target gas may include an electrochemical gas sensor and a circuit. In some embodiments, the electrochemical gas sensor may include a reference electrode and a sensing electrode, the sensing electrode being configured to generate a current in response to the target gas. In some embodiments, the circuit may include a first transistor, the first transistor including a first terminal electrically coupled to the reference electrode, a second terminal electrically coupled to a ground voltage terminal, and a first gate terminal electrically coupled to the ground voltage terminal and to a voltage source through a capacitive element. The circuit may also include a second transistor, the second transistor including a third terminal electrically coupled to the sensing electrode, a fourth terminal electrically coupled to the ground voltage terminal, and a second gate terminal electrically coupled to the ground voltage terminal and to a voltage source through a capacitive element. In some embodiments, in an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal may be electrically coupled to the ground voltage terminal, causing the reference electrode and the sensing electrode to be electrically coupled to the ground voltage terminal through the first transistor and the second transistor, respectively. In some embodiments, the capacitive element may cause a delay in the electrical coupling of the reference electrode and the sensing electrode to the voltage source to prevent damage to the device when the device is powered on.

[0012] In some embodiments, the circuit may be configured so that in an instance where the first gate terminal and the second gate terminal are grounded, the first terminal and the third terminal are shorted to the second terminal and the fourth terminal, respectively, thereby causing the reference electrode and the sensing electrode to be connected to the ground voltage terminal. In some embodiments, the circuit may be configured so that in an instance where the electrochemical gas sensor is powered on, the voltage source applies at least a cut-off voltage at the first gate terminal and the second gate terminal, thereby causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a diode. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a resistive element. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the ground voltage terminal through a capacitive element. In some embodiments, the first terminal and the third terminal may be electrically coupled to the voltage source so that in an instance where the electrochemical gas sensor is powered on, the voltage source may apply a bias voltage to the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor when the electrochemical gas sensor is powered on. The sensing system may also be configured so that in an instance where the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded.

[0013] The methods described herein may be performed using any of the devices, circuits, sensors, apparatuses, systems, or components described herein. In some embodiments, the method may be a method of operating an electronic circuit for an electrochemical gas sensor. In some embodiments, the electronic circuit may include a first transistor including a first terminal configured to be electrically coupled to a ground voltage terminal and a second terminal electrically coupled to a reference terminal of the electrochemical gas sensor. In some embodiments, the electronic circuit may further include a second transistor including a third terminal configured to be electrically coupled to a ground voltage terminal and a fourth terminal electrically coupled to a sensing terminal of the electrochemical gas sensor. In some embodiments, the circuit may further include a capacitive element configured to delay electrical coupling of at least one of the first transistor and the second transistor to the ground voltage terminal. In any case, the method for operating such a circuit for an electrochemical gas sensor may include disconnecting the reference terminal and the sensing terminal from the ground voltage terminal in an instance in which the electrochemical gas sensor is powered on. In some embodiments, the method for operating such a circuit for an electrochemical gas sensor may also include, in an instance in which the electrochemical gas sensor is powered off, electrically coupling the reference terminal and the sensing terminal to a ground voltage terminal via the first terminal and the third terminal, respectively, so that the potential of the reference terminal and the potential of the sensing terminal are equal.

[0014] Various embodiments illustrated herein disclose a method of operating an electronic circuit for an electrochemical gas sensor. The electronic circuit may include a first transistor having a first terminal electrically coupled to a ground voltage terminal, and a second terminal electrically coupled to a reference terminal of the electrochemical gas sensor. In some embodiments, the electronic circuit may include a second transistor having a first terminal electrically coupled to the ground voltage terminal, and a second terminal electrically coupled to a sensing terminal of the electrochemical gas sensor. The method may include, in an instance in which the electrochemical gas sensor is powered on, disconnecting the reference terminal and the sensing terminal from the ground voltage terminal. In addition, the method may include, in an instance in which the electrochemical gas sensor is powered off, connecting the reference terminal and the sensing terminal to the ground voltage terminal so that the reference terminal and the sensing terminal are at similar or identical voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The description of the illustrative embodiments may be read in conjunction with the accompanying drawings. It will be appreciated that, for simplicity and clarity of illustration, the elements illustrated in the various figures are not necessarily drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating the teachings of the present disclosure are shown and described with respect to the various figures presented herein, in which:

[0016] Figure 1A conventional electronic circuit for an electrochemical gas sensor is illustrated;

[0017] Figure 2A and 2B illustrates a schematic diagram of a sensing system according to one or more embodiments described herein;

[0018] Figures 3A-3D illustrates various schematic diagrams of electronic circuits for an electrochemical gas sensor in accordance with at least some of the embodiments described herein; and

[0019] Figure 4 A flow chart of a method for operating an electrochemical gas sensor in a sensing system according to one or more embodiments described herein is illustrated. DETAILED DESCRIPTION

[0020] Some embodiments of the present disclosure will now be more fully described below with reference to the accompanying drawings, in which some but not all embodiments of the present disclosure are shown. In fact, these disclosures can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. The terms used in this patent are not intended to be restrictive, as long as the devices described herein or their parts can be attached or utilized in other orientations.

[0021] The term "comprising" means including but not limited to, and should be interpreted in the manner in which it is commonly used in a patent context. The use of broader terms such as "including," "comprising," and "having" should be understood to provide support for narrower terms such as "consisting of," "consisting essentially of," and "composed essentially of."

[0022] The phrases "in one embodiment," "according to one embodiment," "in some embodiments," "in some examples," "in some instances," "in that regard," "in some configurations," "in some implementations," etc. generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure, or may be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

[0023] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0024] If the specification states that a component or feature "may", "could", "should", "will", "preferably", "perhaps", "usually", "optionally", "for example", "often", or "might" (or other such language) be included or have a property, then that particular component or feature is not required to be included or have that property. Such a component or feature may be optionally included in some embodiments, or it may be excluded.

[0025] The term "switch element" as used herein corresponds to a switch configured to maintain or interrupt an electrical path between two electrical components and / or electronic components. In some examples, the switch element may include, but is not limited to, a relay, a transistor, a reed switch, a toggle switch, and the like. In some embodiments, the switch element may correspond to a normally closed (NC) type switch element or a normally open (NO) type switch element. The NC type switch element may be configured to operate in a closed (CLOSED) state when the switch element is not connected to a power source, and may be configured to operate in an open (OPEN) state when the switch element is connected to a power source. In addition, the NO type switch element may be configured to operate in a closed state when the switch element is connected to a power source, and may be configured to operate in an open state when the switch element is not connected to a power source. In some embodiments, in a closed state, the switch element may be configured to maintain an electrical path between two electrical / electronic components. In addition, in some embodiments, in an open state, the switch element may be configured to interrupt the electrical path between two electrical / electronic components.

[0026] Conventional electrochemical gas sensors often include a reference electrode and a sensing electrode, the sensing electrode being configured to generate a current when in contact with a gas to be detected (also referred to as a "target gas") (e.g., when the target gas diffuses in the electrochemical gas sensor). To enable detection of the target gas, as discussed above, a bias voltage is applied to the sensing electrode relative to the reference electrode. In some examples, the bias voltage can be zero, for example, the voltage at the sensing electrode can be equal to the voltage on the reference electrode.

[0027] In an instance where the electrochemical gas sensor is powered off, the bias voltage applied at the sensing electrode relative to the reference electrode is removed. Typically, for a conventional electrochemical gas sensor, when the bias voltage between the sensing electrode and the reference electrode is removed, the sensing electrode and the reference electrode remain floating (i.e., the sensing electrode and the reference electrode are not connected to any other component or any voltage terminal). Therefore, when a conventional electrochemical gas sensor is used, the target gas surrounding the electrochemical gas sensor may continue to diffuse into the electrochemical gas sensor and react with the sensing electrode when the electrochemical gas sensor is powered off. Such a reaction between the gas and the sensing electrode when the electrochemical gas sensor is powered off may result in the generation of a background current in the electrolyte that may interfere with the reference electrode and is therefore undesirable.

[0028] Conventional methods for avoiding such interference in conventional electrochemical gas sensors include shorting the reference electrode and the sensing electrode by a switching element (e.g., a depletion mode P-JFET such as type J177), as shown in FIG. Figure 1 Further described in .

[0029] Figure 1 A conventional electronic circuit 100 for an electrochemical gas sensor 102 is illustrated. The electrochemical gas sensor 102 includes a reference terminal 104, a sensing terminal 106, and a counter terminal 108. The reference terminal 104, the sensing terminal, and the counter terminal 108 are coupled to a reference electrode, a sensing electrode, and a counter electrode in the electrochemical gas sensor 102, respectively. The reference terminal 104, the sensing terminal 106, and the counter terminal 108 are electrically coupled to a measurement and control circuit 110. More specifically, the reference terminal is coupled to a first input terminal 112 of the measurement and control circuit 110, and the counter terminal 108 is coupled to a first output terminal 114 of the measurement and control circuit 110. In addition, a second input terminal 116 of the measurement and control circuit 110 is coupled to a first voltage source 118. The first voltage source 118 is configured to apply a reference voltage at the second input terminal 116 of the measurement and control circuit 110. The measurement and control circuit 110 is configured to maintain the reference voltage at the reference terminal 104 by changing the voltage at the counter terminal 108.

[0030] The sensing terminal 106 is electrically coupled to a third input terminal 122 of the measurement and control circuit 110. A fourth input terminal 124 of the measurement and control circuit 110 is coupled to a second voltage source 126. The second voltage source 126 is configured to supply a sensing voltage at the fourth input terminal 124 of the measurement and control circuit 110. In addition, the measurement and control circuit 110 includes a second output terminal 127, through which the voltage at the sensing terminal 106 is measured. The difference between the sensing voltage and the reference voltage corresponds to a bias voltage between the sensing terminal 106 and the reference terminal 104. In some examples, the bias voltage is zero, for example, the first voltage source 118 and the second voltage source 126 supply voltages of the same or similar magnitude to the reference terminal 104 and the sensing terminal 106, respectively.

[0031] Additionally, the reference terminal 104 and the sense terminal 106 are coupled via a switch element 128. The switch element 128 may be a normally closed "NC" type switch element such that when power (charge flow, such as current) is applied to the switch element 128, the switch element operates in an open state, thereby electrically decoupling the reference terminal 104 and the sense terminal 106. When power is removed, the switch element 128 operates in a closed state, thereby shorting the reference terminal 104 and the sense terminal 106.

[0032] An example of the NC type switching element 128 may include a P-JFET transistor 130. In the case where the transistor 130 is used as the switching element 128, the reference terminal 104 is coupled to a first terminal 132 of the transistor 130, and the sensing terminal 106 is coupled to a second terminal 134 of the transistor 130. The first terminal 132 of the transistor 130 corresponds to a drain terminal of the transistor 130, and the second terminal 134 of the transistor 130 corresponds to a source terminal of the transistor 130. In addition, the transistor 130 includes a gate terminal 136 coupled to a third voltage source 138. The third voltage source 138 is configured to supply a cutoff voltage to the gate terminal 136. When the electrochemical gas sensor 102 is powered off, the electrochemical gas sensor 102 is disconnected from the measurement and control circuit 110. In addition, when the electrochemical gas sensor 102 is powered off, the transistor 130 is disconnected from the third voltage source 138. Thus, transistor 130 operates in an ON state (because transistor 130 is a P-JFET), causing second terminal 134 to become electrically coupled with first terminal 132 , thereby shorting reference terminal 104 with sense terminal 106 .

[0033] On the other hand, when the electrochemical gas sensor 102 is powered on, the third voltage source 138 applies a cutoff voltage to the gate terminal 136 of the transistor 130. Therefore, the transistor 130 operates in an OFF state, causing the second terminal 134 to be electrically decoupled from the first terminal 132. This also causes the sensing terminal 106 to be decoupled from the reference terminal 104. In addition, when the electrochemical gas sensor 102 is powered on, the reference terminal 104 and the sensing terminal 106 are connected to the measurement and control circuit 110.

[0034] During operation of the electrochemical gas sensor 102, the magnitude of the voltage provided by the first voltage source 118 and the second voltage source 126 can be optionally modulated to improve the sensitivity of the electrochemical gas sensor 102, or to perform diagnostic functions on the main sensing electrode or the counter electrode. In addition, the bias voltage can be changed to electrochemically modify the sensing electrode surface, such as to remove contaminants from the electrode. Such voltage modulation can cause a voltage change at the first terminal 132 and / or the second terminal 134 of the transistor 130, which can also cause the transistor 130 to switch to an on state. As discussed, in the on state, the first terminal 132 becomes electrically coupled to the second terminal 134, thereby shorting the reference terminal to the sensing terminal when the electrochemical gas sensor 102 is powered on. Such a scenario is undesirable. Therefore, there has long been a need in the industry for an improved electronic circuit for an electrochemical gas sensor that does not cause these undesirable situations.

[0035] There is a long-standing industry need for continued miniaturization of electrochemical gas sensors, which in part means that it is desirable to operate electrochemical gas sensors at lower voltages. Although some electrochemical gas sensors and operational amplifiers are capable of operating at lower voltages, conventional transistors such as transistor 130 are not capable of operating at lower voltages. For example, the gate-source cutoff voltage of a J177 transistor can be as high as 2.5 volts.

[0036] In accordance with an embodiment of the present disclosure, an electronic circuit for an electrochemical gas sensor is disclosed below. In some embodiments, the electronic circuit includes a first switch element and a second switch element. In some embodiments, the first switch element and the second switch element may correspond to an NC-type switch element, which is configured to operate in a closed or on state when power is not applied to the switch element. In addition, when power is applied to the NC-type switch element, the switch element operates in a disconnected or off state. Some examples of switch elements may include, but are not limited to, transistors.

[0037] In some embodiments, the first switch element and the second switch element are electrically coupled to a reference terminal and a sensing terminal of the electrochemical gas sensor, respectively. In addition, the first switch element and the second switch element can be coupled to a voltage terminal. In some embodiments, the voltage terminal can correspond to an electrical terminal maintained at a predefined voltage or potential. For example, in some embodiments, the voltage terminal can be maintained at a ground voltage.

[0038] When the electrochemical gas sensor is to be operated, a bias voltage may be maintained between the reference terminal and the sensing terminal. In addition, when the electrochemical gas sensor is to be operated, a cutoff voltage may be applied at the first switching element and the second switching element, causing the first switching element and the second switching element to operate in a closed state. Without wishing to be bound by any particular theory, since the reference terminal and the sensing terminal are connected to different switching elements, a voltage change at the reference terminal and / or the sensing terminal may only affect the corresponding switching element. Thus, a short circuit of the reference terminal and the sensing terminal when the electrochemical gas sensor is powered on is avoided.

[0039] In some embodiments, when the electrochemical gas sensor is powered off, the cutoff voltage is removed from the first switch element and the second switch element, causing the first switch element and the second switch element to operate in the on state. When the first switch element and the second switch element are operated in the on state, the first switch element and the second switch element can respectively connect the reference terminal and the sensing terminal of the electrochemical gas sensor to the voltage terminal. Therefore, in some embodiments, when the electrochemical gas sensor is powered off, the sensing terminal and the reference terminal are at a similar or identical voltage. In some embodiments, when the electrochemical gas sensor is powered off, the reference terminal and the sensing terminal of the electrochemical gas sensor are grounded when the predefined voltage potential corresponds to the ground voltage. Without wishing to be bound by any particular theory, by grounding the reference terminal and the sensing terminal, any generated background current is grounded when the electrochemical gas sensor is powered off. This avoids generating a potential at a terminal (e.g., a sensing terminal) of the electrochemical gas sensor.

[0040] Furthermore, in some embodiments, the sensing system may include a first transistor including a first terminal electrically coupled to a reference electrode, a second terminal electrically coupled to a ground voltage terminal, and a gate terminal electrically coupled to the ground voltage terminal and a voltage source. In some embodiments, the sensing system may include a second transistor including a first terminal electrically coupled to a sensing electrode, a second terminal electrically coupled to the ground voltage terminal, and a gate terminal electrically coupled to the ground voltage terminal and to a voltage source. In some embodiments, in an instance where the electrochemical gas sensor is powered off, the gate terminals of the first transistor and the second transistor may be grounded, causing the reference electrode and the sensing electrode of the electrochemical gas sensor to be connected to the ground voltage terminal through the first transistor and the second transistor, respectively.

[0041] In some embodiments, the first terminal of the first transistor may be referred to as a "first terminal", the second terminal of the first transistor may be referred to as a "second terminal", the gate terminal of the first transistor may be referred to as a "first gate terminal", the first terminal of the second transistor may be referred to as a "third terminal", the second terminal of the second transistor may be referred to as a "fourth terminal", and the gate terminal of the second transistor may be referred to as a "second gate terminal".

[0042] Thus, in some embodiments, the electronic circuit may be configured to operate at least a portion of the functions of the electrochemical gas sensor. In some embodiments, the electrochemical gas sensor may include a reference electrode and a sensing electrode, the sensing electrode being configured to react with the target gas to generate an electric current. In some embodiments, the electronic circuit may include at least a first switching element and a second switching element. In some embodiments, the first switching element may be electrically coupled to a reference terminal and a ground voltage terminal of the electrochemical gas sensor. In some embodiments, the second switching element may be electrically coupled to a sensing terminal and a ground voltage terminal of the electrochemical gas sensor. In some embodiments, the first switching element and the second switching element may be configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal in an instance in which the electrochemical gas sensor is powered off, so that the current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered off flows to the ground voltage terminal and the potential at the reference terminal and the potential at the sensing terminal remain equal.

[0043] In some embodiments, the first switch element and the second switch element can be configured to ground a reference electrode and a sensing electrode of the electrochemical gas sensor to a ground voltage terminal via the reference terminal and the sensing terminal, respectively, in an instance in which the electrochemical gas sensor is powered off. In some embodiments, the first switch element corresponds to a first transistor, and the second switch element corresponds to a second transistor. In some embodiments, the first transistor may include a first terminal electrically coupled to the ground voltage terminal, and a second terminal electrically coupled to the reference terminal of the electrochemical gas sensor. In some embodiments, the second transistor may include a third terminal electrically coupled to the ground voltage terminal, and a fourth terminal electrically coupled to the sensing terminal of the electrochemical gas sensor.

[0044] In some embodiments, the first terminal and the third terminal may correspond to the drain terminal, and the second terminal and the fourth terminal may correspond to the source terminal. In some embodiments, the first terminal and the third terminal may correspond to the source terminal, and the second terminal and the fourth terminal may correspond to the drain terminal. In some embodiments, the first transistor may include a first gate terminal, and the second transistor may include a second gate terminal. In some embodiments, the first gate terminal may be electrically coupled to the second gate terminal, the voltage source, and the ground voltage terminal. In an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal may be grounded, causing the first terminal and the third terminal to be shorted to the second terminal and the fourth terminal, respectively. In an instance in which the electrochemical gas sensor is powered on, the voltage source may be caused to apply at least a cutoff voltage to the first gate terminal and the second gate terminal, causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively.

[0045] In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to a voltage source through a diode, the diode being configured to cause a delay in the electrical coupling of the first gate terminal and the second gate terminal to the voltage source to prevent damage to the electrochemical gas sensor when the electrochemical gas sensor is powered on. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a resistive element. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to a ground voltage terminal through a capacitive element. In some embodiments, the first terminal and the third terminal may also be coupled to a voltage source, so that in an instance in which the electrochemical gas sensor is powered on, the voltage source applies a bias voltage at the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor, respectively, when the electrochemical gas sensor is powered on, and in an instance in which the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded. In some embodiments, the sensing terminal of the electrochemical gas sensor may be electrically coupled to a sensing electrode in the electrochemical gas sensor, and the reference terminal of the electrochemical gas sensor may be electrically coupled to a reference electrode in the electrochemical gas sensor.

[0046] According to some embodiments, a device for sensing a target gas may include an electrochemical gas sensor and a circuit. In some embodiments, the electrochemical gas sensor may include a reference electrode and a sensing electrode, the sensing electrode being configured to generate a current in response to the target gas. In some embodiments, the circuit may include a first transistor, the first transistor including a first terminal electrically coupled to the reference electrode, a second terminal electrically coupled to a ground voltage terminal, and a first gate terminal electrically coupled to the ground voltage terminal and to a voltage source through a capacitive element. The circuit may also include a second transistor, the second transistor including a third terminal electrically coupled to the sensing electrode, a fourth terminal electrically coupled to the ground voltage terminal, and a second gate terminal electrically coupled to the ground voltage terminal and to a voltage source through a capacitive element. In some embodiments, in an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal may be electrically coupled to the ground voltage terminal, causing the reference electrode and the sensing electrode to be electrically coupled to the ground voltage terminal through the first transistor and the second transistor, respectively. In some embodiments, the capacitive element may cause a delay in the electrical coupling of the reference electrode and the sensing electrode to the voltage source to prevent damage to the device when the device is powered on.

[0047] In some embodiments, the circuit may be configured so that in an instance where the first gate terminal and the second gate terminal are grounded, the first terminal and the third terminal are shorted to the second terminal and the fourth terminal, respectively, thereby causing the reference electrode and the sensing electrode to be connected to the ground voltage terminal. In some embodiments, the circuit may be configured so that in an instance where the electrochemical gas sensor is powered on, the voltage source applies at least a cutoff voltage at the first gate terminal and the second gate terminal, thereby causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a diode. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the voltage source through a resistive element. In some embodiments, the first gate terminal and the second gate terminal may be electrically coupled to the ground voltage terminal through a capacitive element. In some embodiments, the first terminal and the third terminal may be electrically coupled to the voltage source so that in an instance where the electrochemical gas sensor is powered on, the voltage source may apply a bias voltage to the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor when the electrochemical gas sensor is powered on. The sensing system may also be configured so that in an instance where the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded.

[0048] The methods described herein may be performed using any of the devices, circuits, sensors, apparatuses, systems, or components described herein. In some embodiments, the method may be a method of operating an electronic circuit for an electrochemical gas sensor. In some embodiments, the electronic circuit may include a first transistor, the first transistor including a first terminal configured to be electrically coupled to a ground voltage terminal and a second terminal electrically coupled to a reference terminal of the electrochemical gas sensor. In some embodiments, the electronic circuit may further include a second transistor, the second transistor including a third terminal configured to be electrically coupled to a ground voltage terminal and a fourth terminal electrically coupled to a sensing terminal of the electrochemical gas sensor. In some embodiments, the circuit may further include a capacitive element configured to delay electrical coupling of at least one of the first transistor and the second transistor to the ground voltage terminal. In any case, the method for operating such a circuit for an electrochemical gas sensor may include, in an instance in which the electrochemical gas sensor is powered on, disconnecting the reference terminal and the sensing terminal from the ground voltage terminal. In some embodiments, the method for operating such a circuit for an electrochemical gas sensor may also include, in an instance in which the electrochemical gas sensor is powered off, electrically coupling the reference terminal and the sensing terminal to a ground voltage terminal via the first terminal and the third terminal, respectively, so that the potential of the reference terminal and the potential of the sensing terminal are equal.

[0049] Figure 2A and 2B A schematic diagram of a sensing system 200 according to some embodiments described herein is illustrated. As shown, the sensing system 200 includes an electrochemical gas sensor 202, an electronic circuit 203, and a measurement and control circuit 208. The electronic circuit 203 may include a first switching element 204 and a second switching element 206. The electrochemical gas sensor 202 may include a sensing terminal 210 and a reference terminal 212. In some embodiments, the electrochemical gas sensor 202 may also include a counter terminal 214. In some embodiments, the sensing terminal 210 may be coupled to a sensing electrode (not shown) in the electrochemical gas sensor 202. Similarly, in some embodiments, the reference terminal 212 and the counter terminal 214 may be coupled to a reference electrode and a counter electrode in a housing of the electrochemical gas sensor 202.

[0050] In some embodiments, the reference terminal 212, the sense terminal 210, and / or the counter terminal 214 can be connected to the measurement and control circuit 208. In some embodiments, the reference terminal 212, the sense terminal 210, and the counter terminal 214 can be coupled to the measurement and control circuit 208 through one or more switches 207a, 207b, and 207c, respectively. The one or more switches 207a, 207b, and 207c can correspond to solid-state switches configured to power on or off the electrochemical gas sensor 202. For example, to power on the electrochemical gas sensor 202, the one or more switches 207a, 207b, and 207c can be configured to operate in a closed state, such as Figure 2A In addition, in order to power off the electrochemical gas sensor 202, the one or more switches 207a, 207b and 207c can be configured to be in an open state, such as Figure 2B As shown in the figure.

[0051] In some embodiments, the measurement and control circuit 208 may be configured to supply a reference voltage and a sensing voltage to the reference terminal 212 and the sensing terminal 210, respectively, when the sensing system 200 is powered on. In some embodiments, the measurement and control circuit 208 may include a first amplifier 216 and a second amplifier 218. In some embodiments, the first amplifier 216 and the second amplifier 218 may be implemented using an operational amplifier (OP-AMP). However, the scope of the present disclosure is not limited to implementing the first amplifier 216 and the second amplifier 218 using an OP-AMP. In some embodiments, known transistor circuits may be used as the first amplifier 216 and the second amplifier 218 without departing from the scope of the present disclosure.

[0052] In some embodiments, the first amplifier 216 and the second amplifier 218 may include first input terminals 220a and 220b, second input terminals 222a and 222b, and output terminals 224a and 224b, respectively. The first input terminal 220a of the first amplifier 216 may be coupled to the reference terminal 212 of the electrochemical gas sensor 202, for example, through a switch 207b. The second input terminal 222a of the first amplifier 216 may be coupled to a first voltage source 226. In some embodiments, the first voltage source 226 may be configured to apply a reference voltage to the second input terminal 222a. In addition, the output terminal 224a of the first amplifier 216 may be coupled to the counter terminal 214 of the electrochemical gas sensor 202, for example, through a switch 207c.

[0053] The first input terminal 220b of the second amplifier 218 can be coupled to the sensing terminal 210 of the electrochemical gas sensor 202, for example, through the switch 207a. The second input terminal 222b of the second amplifier 218 can be coupled to the second voltage source 228. In some embodiments, the second voltage source 228 can be configured to apply a sensing voltage to the second input terminal 222b of the second amplifier 218. In addition, the output terminal 224b of the second amplifier 218 can be coupled to the first input terminal 220a, for example, through the resistor element 230.

[0054] In some embodiments, if the first amplifier 216 and the second amplifier 218 are implemented using op-amps, the voltages at the first input terminals 220a and 220b of the first amplifier 216 and the second amplifier 218 may be similar to, substantially equal to, or equal to the voltages at the second input terminals 222a and 222b of the first amplifier 216 and the second amplifier 218, respectively. Therefore, the voltage at the first input terminal 220a of the first amplifier 216 may be similar to, substantially equal to, or equal to the reference voltage. In addition, the voltage at the first input terminal 220b of the second amplifier 218 may be similar to, substantially equal to, or equal to the sensing voltage. In some embodiments, if the sensing terminal 210 and the reference terminal 212 of the electrochemical gas sensor 202 are coupled to the first input terminal 220a and the first input terminal 220b, respectively, the sensing voltage and the reference voltage may be applied to the sensing terminal 210 and the reference terminal 212, respectively.

[0055] In addition, in some embodiments, the reference terminal 212 and the sense terminal 210 may be electrically coupled to the first switch element 204 and the second switch element 206, respectively. In some embodiments, the first switch element 204 and the second switch element 206 may also be coupled to a ground voltage terminal 232. In some embodiments, the ground voltage terminal 232 may correspond to an electrical terminal, for example, an electrical terminal maintained at a predefined voltage. For example, the ground voltage terminal 232 may be maintained at a ground voltage, as further described in conjunction with Figures 3a-3d. In some embodiments, the first switch element 204 and the second switch element 206 may also be electrically coupled to a third voltage source 234. The third voltage source 234 may be configured to supply a cutoff voltage to the first switch element 204 and the second switch element 206. In some embodiments, the first switch element 204 and the second switch element 206 may be configured to connect the reference terminal 212 and the sense terminal 210 to the ground voltage terminal 232, for example, when the first switch element 204 and the second switch element 206 are operated in a closed state. Furthermore, in some embodiments, the first switch element 204 and / or the second switch element 206 may be configured to disconnect the reference terminal 212 and / or the sensing terminal 210 from the ground voltage terminal 232, for example, when the first switch element 204 and / or the second switch element 206 are operated in an open state. In some embodiments, the first switch element 204 and the second switch element 206 may be operated in an open state when the first switch element 204 and the second switch element 206 receive a cutoff voltage from the first voltage source 226. In some embodiments, the first switch element 204 and the second switch element 206 may receive a cutoff voltage when the sensing system 200 is powered on. Furthermore, in some embodiments, the first switch element 204 and the second switch element 206 may be operated in a closed state when the first switch element 204 and the second switch element 206 do not receive a cutoff voltage from the first voltage source 118. In some embodiments, the first switch element 204 and the second switch element 206 do not receive a cutoff voltage when the sensing system 200 is powered off.

[0056] In some embodiments, first voltage source 226, second voltage source 228, and third voltage source 234 may correspond to a single voltage source configured to supply reference voltage, sensing voltage, and ground voltage terminal 232. Some examples of a single voltage source may include, but are not limited to, a battery, a switch mode power supply (SMPS), and the like.

[0057] In operation, when the sensing system 200 is powered on (e.g., in response to a user of the electrochemical gas sensor 202 pressing a power button (not shown), in response to receiving a signal indicating a power-on command, in response to feedback from a sensor or from the circuit itself, etc.), the one or more switches 207a, 207b, and 207c may be operated in a closed state. Thus, in some embodiments, the first voltage source 226, the second voltage source 228, and the third voltage source 234 may supply a reference voltage to the reference terminal 212, a sensing voltage to the sensing terminal 210, and a cutoff voltage to the first switching element 204 and the second switching element 206, respectively. According to some embodiments, in an instance in which the cutoff voltage is applied to the first switching element 204 and the second switching element 206, the first switching element 204 and the second switching element 206 may be operated in an open state. Furthermore, as discussed, in the open state, the first switching element 204 and the second switching element 206 may decouple the reference terminal 212 and the sensing terminal 210 from the ground voltage terminal 232, respectively. Thus, in some embodiments, the reference terminal 212 may receive a reference voltage from the first amplifier 216. Additionally or alternatively, in some embodiments, the sense terminal 210 may receive a sense voltage from the second amplifier 218. In some embodiments, the difference between the reference voltage and the sense voltage may correspond in part or in whole to a bias voltage between the reference terminal 212 and the sense terminal 210.

[0058] When the gas diffuses in the electrochemical gas sensor 202, the gas reacts with the sensing electrode coupled to the sensing terminal 210 to generate a current. In some embodiments, the generated current causes a change in the voltage, such as a voltage swing, at the second output terminal 224b of the second amplifier 218. The magnitude of the voltage swing may indicate the gas concentration detected by the sensing electrode (which is coupled to the sensing terminal 210 according to some embodiments).

[0059] In some embodiments, in instances where the sensing system 200 is powered off, the one or more switches 207a, 207b, and 207c are operated in an open state, such as Figure 2B. Thus, in such an embodiment, the first voltage source 226, the second voltage source 228, and the third voltage source 234 can be disconnected from the electrochemical gas sensor 202. Therefore, the first switch element 204 and the second switch element 206 do not receive the cut-off voltage. As discussed, when the first switch element 204 and the second switch element 206 do not receive the cut-off voltage, the first switch element 204 and the second switch element 206 can be operated in a closed state, thereby connecting the reference terminal 212 and the sensing terminal 210 to the ground voltage terminal 232. Because both the reference terminal 212 and the sensing terminal 210 are connected to the ground voltage terminal 232 (i.e., the reference terminal 212 and the sensing terminal 210 are at the same potential), any background current (e.g., a current generated due to a reaction between the sensing electrode and the diffused gas) can flow through the electrochemical gas sensor 202 to the voltage terminal. This avoids an offset in the potential at the sensing electrode 210.

[0060] In some embodiments, the first switch element 204 and / or the second switch element 206 may be, include or comprise a transistor such as a P-JFET. Figures 3A-3D . However, the scope of the present disclosure is not limited to embodiments in which the first switch element 204 and / or the second switch element 206 are, include, or contain P-JFET transistors. For example, in some embodiments, the first switch element 204 and / or the second switch element 206 may be, include, or contain a p-type metal oxide semiconductor field effect transistor (P-MOSFET). In other embodiments, the first switch element 204 and / or the second switch element 206 may be, include, or contain any other suitable switch, for example, many types of NC-type switches. In alternative embodiments, the first switch element 204 and / or the second switch element 206 may be implemented using n-type transistors without departing from the scope of the present disclosure.

[0061] In some examples, the scope of the present disclosure is not limited to the aforementioned circuitry of sensing system 200. In alternative embodiments, sensing system 200 can include additional electrical / electronic components (eg, additional resistive elements, additional capacitive elements, etc.).

[0062] Figures 3A-3D Various schematic diagrams are illustrated for electronic circuit 203 of electrochemical gas sensor 202 in accordance with one or more embodiments described herein.

[0063] refer to Figure 3A, the electronic circuit 203 includes a first transistor 302 and a second transistor 304. The first transistor 302 may have a first terminal 306a, a second terminal 308a, and a gate terminal 310a. Similarly, in some embodiments, the second transistor 304 may include a first terminal 306b, a second terminal 308b, and a gate terminal 310b. In some embodiments, the first terminal 306a and / or the first terminal 306b of the first transistor 302 and / or the second transistor 304 may correspond to the drain terminal of the first transistor 302 and / or the second transistor 304, respectively. In addition, in some embodiments, the second terminal 308a and / or the second terminal 308b of the first transistor 302 and / or the second transistor 304 corresponds to the source terminal of the first transistor 302 and / or the second transistor 304, respectively. In some embodiments, the first terminal 306a and / or the first terminal 306b of the first transistor 302 and / or the second transistor 304 and the second terminal 308a and / or the second terminal 308b are interchangeable, respectively. Hereinafter, the first terminal 306a of the first transistor 302 and the first terminal 306b of the second transistor 304 are respectively referred to as drain terminals of the first transistor 302 and the second transistor 304. Likewise, hereafter, the second terminal 308a of the first transistor 302 and the second terminal 308b of the second transistor 304 have been respectively referred to as source terminals of the first transistor 302 and the second transistor 304. However, such references in any embodiments described herein are not intended to limit the functionality of any terminal of any transistor.

[0064] In some embodiments, the first terminal 306a of the first transistor 302 may be referred to as the "first terminal 306a", the second terminal 308a of the first transistor 302 may be referred to as the "second terminal 308a", the gate terminal 310a of the first transistor 302 may be referred to as the "first gate terminal 310a", the first terminal 306b of the second transistor 304 may be referred to as the "third terminal 306b", the second terminal 308b of the second transistor 304 may be referred to as the "fourth terminal 308b", and the gate terminal 310b of the second transistor 304 may be referred to as the "second gate terminal 310b".

[0065] In some embodiments, the drain terminal 306a of the first transistor 302 can be coupled to the reference terminal 212 of the electrochemical gas sensor 202. In addition, in some embodiments, the source terminal 308a of the first transistor 302 can be coupled to the ground voltage terminal 312. The ground voltage terminal can be maintained at or close to the ground voltage. In addition, the gate terminal 310a of the first transistor 302 can be coupled to the third voltage source 234, for example, through a resistor element 314 and / or a diode 316. In some embodiments, the diode 316 and / or the resistor element 314 can be coupled together in any suitable configuration, such as a parallel configuration, wherein the positive terminal 318 of the diode 316 is coupled to the third voltage source 234 and the negative terminal 320 of the diode 316 is coupled to the gate terminal 310a of the first transistor 302. In addition, in some embodiments, the gate terminal 310a of the first transistor 302 can be coupled to the ground voltage terminal 312, for example, through a capacitor element 322. Additionally, a gate terminal 310a of the first transistor 302 may be coupled to the second transistor 304, for example via a gate terminal 310b of the second transistor 304. A drain terminal 306b of the second transistor 304 may be coupled to the sensing terminal 210 of the electrochemical gas sensor 202. Furthermore, a source terminal 308b of the second transistor 304 may be coupled to a ground voltage terminal 312.

[0066] For the sake of brevity, Figures 3A-3D However, the reference terminal 212, the sense terminal 210 and / or the counter terminal 214 of the electrochemical gas sensor 202 may be coupled to the measurement and control circuit 208 through one or more switches (eg, via switches 207a, 207b and 207c), respectively.

[0067] In operation, when the sensing system 200 is powered on, the third voltage source 234 can be configured to supply a cut-off voltage to the gate terminal 310a of the first transistor 302 and / or the gate terminal 310b of the second transistor 304. In some embodiments in which the first transistor 302 and / or the second transistor 304 are P-JFETs, when the cut-off voltage is applied to the respective gate terminals (310a and 310b), the first transistor 302 and the second transistor 304 can be configured to operate in a closed state. In some embodiments, in the closed state, the first transistor 302 and / or the second transistor 304 can electrically decouple the drain terminal (308a, 308b) and the source terminal (306a, 306b), respectively. Therefore, in some embodiments, the first transistor 302 can be caused to decouple the reference terminal 212, and the second transistor 304 can be caused to decouple the sensing terminal 210. In some embodiments, one or both of the first transistor 302 and the second transistor 304 can be configured to decouple the reference terminal 212 and / or the sensing terminal 210 from the ground voltage terminal 312. In some embodiments, decoupling the electrochemical gas sensor 202 from the ground voltage terminal 312 can allow the electrochemical gas sensor 202 to be coupled with the measurement and control circuit 208 (because the one or more switches 207a, 207b, and 207c can be configured to operate in a closed state when the sensing system 200 is powered on). For example, in some embodiments, when coupling the electrochemical gas sensor 202 with the measurement and control circuit 208, the measurement and control circuit 208 can apply a bias voltage at the sensing terminal 210 relative to the reference terminal 212. In other words, the difference between the reference voltage and the sensing voltage can be supplied by the measurement and control circuit 208. Thereafter, the electrochemical gas sensor 202 can be coupled to the measurement and control circuit 208 as described above. Figure 2A-2B The electrochemical gas sensor 202 may operate as described. For example, when a gas diffuses in the electrochemical gas sensor 202, the gas may react with a sensing electrode (e.g., a sensing electrode coupled to the sensing terminal 210) to generate a current. The generated current may cause a voltage change, such as a voltage swing, at the output terminal 224b of the second amplifier 218 (in the measurement and control circuit 208). The magnitude of the voltage swing may indicate the concentration of the gas detected by the sensing electrode (coupled to the sensing terminal 210). In some embodiments, the electrochemical gas sensor 202 may include measures for measuring the voltage and interpreting the voltage change as a target gas concentration. In some embodiments, the electrochemical gas sensor 202 may include a processor (not shown) configured to measure the voltage change (e.g., the voltage swing) and determine the concentration of the gas detected by the sensing electrode.

[0068] In some embodiments, during the operation of the electrochemical gas sensor 202, the bias voltage at the sensing terminal 210 relative to the reference terminal 212 can be changed, for example, to improve the sensitivity of the electrochemical gas sensor 202. In some embodiments, the change in the bias voltage can be obtained by changing the sensing voltage and / or the reference voltage. In some embodiments, the reference voltage and / or the sensing voltage can be changed by a processor to change the bias voltage between the sensing terminal 210 and the reference terminal 212. Without wishing to be bound by any particular theory, in some scenarios, changing the bias voltage can cause the voltage at the drain terminals 306a, 306b of the first transistor 302 and / or the second transistor 304 to change. However, because the source terminal 306a of the first transistor 302 and the source terminal 306b of the second transistor 304 are grounded, the first transistor 302 and the second transistor 304 are never switched to a conducting state when the sensing system 200 is powered on. Therefore, for some embodiments, when the sensing system 200 is powered on, the reference terminal 212 and the sense terminal 210 may not be shorted due to a change in the bias voltage between the reference terminal 212 and the sense terminal 210 .

[0069] When the sensing system 200 is powered off, at least in some embodiments, the gate terminals 310a and 310b of the first transistor 302 and the second transistor 304 can be coupled to the ground voltage terminal 312, respectively (because the third voltage source 234 is disconnected from the electronic circuit 203). In some embodiments in which the first transistor 302 and the second transistor 304 are P-JFETs, when the gate terminals 310a and 310b of the first transistor 302 and the second transistor 304 are coupled or coupled to the ground voltage terminal 312, respectively, the first transistor 302 and the second transistor 304 can operate in an on state. In addition, as discussed with respect to some embodiments, when the first transistor 302 and the second transistor 304 operate in an on state, the source terminals 308a and 308b of the first transistor 302 and the second transistor 304 can be connected to the drain terminals 306a and 306b, respectively. Therefore, the reference terminal 212 can be connected to the ground voltage terminal 312. Similarly, the sensing terminal 210 can also be coupled to the ground voltage terminal 312. Thus, when the sensing system 200 is powered off, any background current (due to chemical reactions between the sensing electrode and the gas) is allowed to flow to the ground voltage terminal 312 without causing a voltage to be generated between the two electrodes and its negative consequences being avoided.

[0070] In some embodiments, when the sensing system 200 is powered off, the electronic circuit 203 and the electrochemical gas sensor 202 may have some transient voltages and transient currents. For some embodiments, if the reference terminal 212 and the sensing terminal 210 of the electrochemical gas sensor 202 are connected to the ground voltage terminal 312 as soon as the sensing system 200 is powered off, the transient voltages and transient currents may damage the electrochemical gas sensor 202. In some embodiments, the diode 316 and / or the capacitive element 322 in the electronic circuit 203 can delay the switching of the first transistor 302 and the second transistor 304 to the on state, thereby delaying the coupling of the reference terminal 212 and the sensing terminal 210 to the ground voltage terminal 312. Therefore, for such embodiments, the electrochemical gas sensor 202 is not disturbed by transient voltages and transient currents.

[0071] In some embodiments, the electronic circuit 203 may not include the resistor element 314, as illustrated in FIG3b. However, the scope of the present disclosure is not limited to embodiments in which the source terminals 308a and 308b of the first transistor 302 and the second transistor 304 are connected to the ground voltage terminal 312. Referring to FIG3c, in some alternative embodiments, the source terminals 308a and 308b of the first transistor 302 and the second transistor 304 may be connected to the ground voltage terminal 312 through a second resistor element 324. In addition, the source terminals 308a and 308b of the first transistor 302 and the second transistor 304 may be connected to the fourth voltage source 326 through a third resistor element 328, respectively. In some embodiments, the fourth voltage source 326 may be configured to supply a bias voltage to the source terminals 308a and 308b of the first transistor 302 and the second transistor 304, respectively. In some embodiments, the magnitude of the bias voltage supplied by fourth voltage source 326 may be the same or similar to the magnitude of the bias voltage applied by measurement and control circuit 208 at sensing terminal 210 and reference terminal 212 of electrochemical gas sensor 202 .

[0072] In operation, when the sensing system 200 according to some embodiments is powered on, the source terminals 308a and 308b of the first transistor 302 and the second transistor 304 may receive a bias voltage from the fourth voltage source 326. In some embodiments for which the magnitude of the bias voltage applied at the source terminals 308a and 308b is the same or similar to the magnitude of the bias voltage at the reference terminal 212 and the sense terminal 210 of the electrochemical gas sensor 202, the flow of leakage current from the electrochemical gas sensor 202 through the first transistor 302 and the second transistor 304 may be reduced.

[0073] In addition, when the sensing system 200 of some embodiments is powered off, the source terminals 308a and 308b can be connected to the ground voltage terminal 312. Thereafter, the electronic circuit 203 of such embodiments can be combined with the above Figure 3A The electronic circuit 203 described above operates in a similar manner. For example, when the sensing system 200 is powered off, the first transistor 302 and the second transistor 304 can be operated in an on state, which can cause the drain terminals 306a and 306b to be connected to the source terminals 308a and 308b, respectively. Therefore, the sensing terminal 210 and the reference terminal 212 of such an embodiment can be connected to the ground voltage terminal 312 (i.e., ground).

[0074] However, the scope of the present disclosure is not limited to the embodiment for which the gate terminals 310a and 310b are connected to the third voltage source 234 through diodes. In some alternative embodiments, the gate terminals 310a and 310b may be connected to the third voltage source 234 through the fifth resistive element 330, for example, Figure 3D In some examples, the fifth resistive element 330 is optional, and the gate terminals 310a and 310b can be directly coupled to the third voltage source 234.

[0075] Figure 4 Illustrated is a flow chart 400 of a method for operating an electrochemical gas sensor 202 in a sensing system 200 , according to some embodiments described herein.

[0076] At step 402, the sensing system 200 may include measures for decoupling the reference terminal 212 and the sensing terminal 210 of the electrochemical gas sensor 202 from the ground voltage terminal 232 in an instance in which the sensing system 200 is powered on. In some embodiments, the measures for decoupling as in step 402 may include devices such as the electronic circuit 203, the first switching element 204, the second switching element 206, the first transistor 302, the second transistor 304, and the like. As previously discussed, the first switching element 204 and the second switching element 206 may be NC-type switching elements. Therefore, when the first switching element 204 and the second switching element 206 receive power (e.g., receive power from the third voltage source 234) according to some embodiments, the first switching element 204 and the second switching element 206 may be operated in a disconnected state, which may cause the reference terminal 212 and the sensing terminal 210 of the electrochemical gas sensor 202 to be decoupled from the ground voltage terminal 232.

[0077] At step 404, the sensing system 200 may include measures for coupling the reference terminal 212 and the sensing terminal 210 of the electrochemical gas sensor 202 to the ground voltage terminal 232 in an instance in which the sensing system 200 is powered off. In some embodiments, the measures for coupling as in step 404 may include devices such as the electronic circuit 203-300d, the first switching element 204, the second switching element 206, the first transistor 302, the second transistor 304, and the like. As previously discussed, the first switching element 204 and the second switching element 206 according to some embodiments may be NC-type switching elements. According to such embodiments, when the first switching element 204 and the second switching element 206 do not receive power from the third voltage source 234, the first switching element 204 and the second switching element 206 may operate in a closed state, which may cause the coupling of the reference terminal 212 and the sensing terminal 210 to the ground voltage terminal 232.

[0078] In some embodiments, one or more of the operations, steps, or processes described herein may be modified or further expanded as described below. In addition, in some embodiments, additional optional operations may also be included, for example, in the method of flowchart 400. It should be appreciated that each of the modifications, optional additions, and / or expansions described herein may be included with operations previously described herein, either alone or in combination with any other from among the features described herein.

[0079] The method descriptions, diagrams, and process flow charts provided are provided only as illustrative examples, and are not intended to require or imply that the steps of the various embodiments must each or all be performed and / or should be performed in the order presented or described. As will be appreciated by those skilled in the art, the steps of this sequence in some or all of the described embodiments may be performed in any order. Words such as "thereafter," "then," "next," etc. are not intended to limit the order of the steps; these words are only used to guide the reader through the description of the method. In addition, any reference to a claim element in the singular, such as using the article "one," "an," or "the," should not be interpreted as limiting the element to the singular.

[0080] Many modifications and other embodiments of the inventions set forth herein will occur to those skilled in the art who have benefited from the teachings presented in the preceding description and the associated drawings. Although the drawings show only certain components of the devices and systems described herein, it is to be understood that various other components may be used in conjunction with the systems. Therefore, it is to be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, the steps in the methods described above may not necessarily occur in the order depicted in the drawings, and in some cases, one or more of the depicted steps may occur substantially simultaneously, or may involve additional steps. Although specific terms are employed herein, they are used only in a general and descriptive sense and not for limiting purposes.

Claims

1. An electronic circuit for an electrochemical gas sensor, the electrochemical gas sensor comprising a reference electrode and a sensing electrode, the sensing electrode being configured to react with a target gas to generate an electric current, the electronic circuit comprising: a first switching element electrically coupled to a reference terminal and a ground voltage terminal of the electrochemical gas sensor; as well as a second switching element electrically coupled to a sensing terminal of the electrochemical gas sensor and the ground voltage terminal, the first switching element corresponds to a first transistor, and the second switching element corresponds to a second transistor, The first transistor comprises a first gate terminal and the second transistor comprises a second gate terminal, wherein the first gate terminal is electrically coupled to the second gate terminal, and wherein, in an instance in which the electrochemical gas sensor is powered off, the first switch element and the second switch element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal so that a current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered off flows to the ground voltage terminal and a potential at the reference terminal and a potential at the sensing terminal remain equal, and The first gate terminal and the second gate terminal are grounded.

2. The electronic circuit according to claim 1, wherein in an instance in which the electrochemical gas sensor is powered off, the first switching element and the second switching element are configured to ground the reference electrode and the sensing electrode of the electrochemical gas sensor to the ground voltage terminal via the reference terminal and the sensing terminal, respectively.

3. The electronic circuit according to claim 1, wherein the first transistor includes a first terminal electrically coupled to the ground voltage terminal, and a second terminal electrically coupled to a reference terminal of the electrochemical gas sensor, and The second transistor includes a third terminal electrically coupled to the ground voltage terminal, and a fourth terminal electrically coupled to a sensing terminal of the electrochemical gas sensor. 4 . The electronic circuit according to claim 3 , wherein the first terminal and the third terminal correspond to drain terminals, and the second terminal and the fourth terminal correspond to source terminals. 5 . The electronic circuit according to claim 3 , wherein the first terminal and the third terminal correspond to source terminals, and the second terminal and the fourth terminal correspond to drain terminals.

6. The electronic circuit according to claim 3, wherein the first gate terminal is electrically coupled to the second gate terminal, a voltage source, and the ground voltage terminal, In an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal are grounded, causing the first terminal and the third terminal to be short-circuited with the second terminal and the fourth terminal, respectively, and in an instance in which the electrochemical gas sensor is powered on, the voltage source applies at least a cutoff voltage at the first gate terminal and the second gate terminal, causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively.

7. The electronic circuit of claim 1 , wherein the first gate terminal and the second gate terminal are electrically coupled to a voltage source via diodes, the diodes being configured to cause a delay in electrical coupling of the first gate terminal and the second gate terminal to the voltage source to prevent damage to the electrochemical gas sensor when the electrochemical gas sensor is powered on. 8 . The electronic circuit of claim 1 , wherein the first gate terminal and the second gate terminal are electrically coupled to a voltage source through a resistance element. 9 . The electronic circuit according to claim 1 , wherein the first gate terminal and the second gate terminal are electrically coupled to the ground voltage terminal through a capacitive element.

10. The electronic circuit according to claim 3, wherein The first terminal and the third terminal are further coupled to a voltage source, and In an instance where the electrochemical gas sensor is powered on, the voltage source applies a bias voltage at the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor, respectively, when the electrochemical gas sensor is powered on, and In instances where the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded.

11. The electronic circuit of claim 1, wherein the sensing terminal of the electrochemical gas sensor is electrically coupled to a sensing electrode in the electrochemical gas sensor, and the reference terminal of the electrochemical gas sensor is electrically coupled to a reference electrode in the electrochemical gas sensor.

12. A device for sensing a target gas, the device comprising: an electrochemical gas sensor comprising a reference electrode and a sensing electrode, the sensing electrode being configured to generate a current in response to a target gas; a first transistor including a first terminal electrically coupled to the reference electrode, a second terminal electrically coupled to a ground voltage terminal, and a first gate terminal electrically coupled to the ground voltage terminal and to a voltage source through a capacitive element; as well as a second transistor including a third terminal electrically coupled to the sensing electrode, a fourth terminal electrically coupled to the ground voltage terminal, and a second gate terminal electrically coupled to the ground voltage terminal and to the voltage source through the capacitive element, wherein the first gate terminal is electrically coupled to the second gate terminal, and wherein, in an instance in which the electrochemical gas sensor is powered off, the first gate terminal and the second gate terminal are electrically coupled to the ground voltage terminal, causing the reference electrode and the sensing electrode to be electrically coupled to the ground voltage terminal through the first transistor and the second transistor, respectively, wherein the first gate terminal and the second gate terminal are grounded, and The capacitive element causes a delay in electrical coupling of the reference electrode and the sensing electrode to the voltage source to prevent damage to the device when the device is powered on.

13. The apparatus of claim 12, wherein in an instance where the first gate terminal and the second gate terminal are grounded, the first terminal and the third terminal are shorted with the second terminal and the fourth terminal, respectively, causing the reference electrode and the sense electrode to be connected to the ground voltage terminal.

14. The apparatus of claim 12, wherein in an instance in which the electrochemical gas sensor is powered on, the voltage source applies at least a cutoff voltage at the first gate terminal and the second gate terminal, causing the first terminal and the third terminal to be disconnected from the second terminal and the fourth terminal, respectively.

15. The device of claim 12, wherein the first gate terminal and the second gate terminal are electrically coupled to the voltage source through diodes.

16. The device of claim 12, wherein the first gate terminal and the second gate terminal are electrically coupled to the voltage source through a resistive element. 17 . The device of claim 12 , wherein the first gate terminal and the second gate terminal are electrically coupled to the ground voltage terminal through a capacitive element.

18. The apparatus of claim 12, wherein the first terminal and the third terminal are electrically coupled to the voltage source, and wherein: In an instance where the electrochemical gas sensor is powered on, the voltage source applies a bias voltage at the first terminal and the third terminal to prevent leakage current from flowing through the first transistor and the second transistor when the electrochemical gas sensor is powered on.

19. The apparatus of claim 12, wherein in an instance in which the electrochemical gas sensor is powered off, the first terminal and the third terminal are grounded.

20. A method of operating an electronic circuit for an electrochemical gas sensor, the electronic circuit comprising: a first transistor including a first terminal configured to be electrically coupled to a ground voltage terminal and a second terminal electrically coupled to a reference terminal of the electrochemical gas sensor; a second transistor including a third terminal configured to be electrically coupled to the ground voltage terminal and a fourth terminal electrically coupled to a sensing terminal of the electrochemical gas sensor; as well as a capacitive element configured to delay electrical coupling of at least one of the first transistor and the second transistor to the ground voltage terminal, wherein the first transistor comprises a first gate terminal and the second transistor comprises a second gate terminal, and wherein the first gate terminal is electrically coupled to the second gate terminal, The method comprises: In an instance in which the electrochemical gas sensor is powered, disconnecting the reference terminal and the sense terminal from the ground voltage terminal; as well as In an instance where the electrochemical gas sensor is powered off, the reference terminal and the sense terminal are electrically coupled to the ground voltage terminal through the first terminal and the third terminal, respectively, so that the potential of the reference terminal and the potential of the sense terminal are equal, and The first gate terminal and the second gate terminal are grounded.

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