Liquid level detection circuit and equipment

Abstract

The utility model provides a liquid level detection circuit and equipment, and relates to the technical field of liquid level detection, and the liquid level detection circuit comprises a plurality of detection channels which are used for accessing external detection signals; the plurality of controllable oscillator circuits are connected with the plurality of detection channels in a one-to-one correspondence manner; and the controllable oscillator circuit is used for starting in turn according to the detection starting signal and a time sequence so as to access an external detection signal for detection. According to the invention, the problem of mutual interference during multi-channel parallel detection is solved. And each detection channel is independently controlled through the corresponding controllable oscillator circuit, so that the channels are ensured not to interfere with each other in the detection process, and the accuracy and reliability of the detection result are improved.

Description

Technical Field

[0001] The present application relates to the technical field of liquid level detection, and in particular to a liquid level detection circuit and device. Background Art

[0002] In current liquid level detection applications, given the common conductive properties of liquids, multi-channel parallel detection is prone to mutual interference. Such interference directly affects the accuracy of the detection results, may significantly increase the error, and even lead to false detection, posing a huge challenge to the overall detection efficiency and reliability. Utility Model Content

[0003] The main purpose of the utility model is to provide a liquid level detection circuit, aiming to solve the mutual interference problem existing in the existing liquid level detection technology during multi-channel parallel detection, and to improve the accuracy and reliability of the detection results.

[0004] In order to achieve the above object, the utility model provides a liquid level detection circuit, the liquid level detection circuit comprising:

[0005] A plurality of detection channels, wherein the detection channels are used to access external detection signals;

[0006] A plurality of controllable oscillator circuits are connected to the plurality of detection channels in a one-to-one correspondence; the controllable oscillator circuits are used to start in turn in a time sequence according to a detection start signal to access an external detection signal for detection.

[0007] Optionally, the controllable oscillator circuit comprises:

[0008] An oscillator circuit, the input end of which is connected to the corresponding detection channel, and the oscillator circuit is used to convert the external probe signal into an oscillation signal of a specific frequency;

[0009] A control circuit, the control circuit being electrically connected to the oscillator circuit, and the control circuit being configured to output a corresponding control signal according to the oscillation signal;

[0010] A controllable power supply circuit, wherein the output end of the controllable power supply circuit is connected to the power supply end of the oscillator circuit, the controlled end of the controllable power supply circuit is connected to the output end of the control circuit, and the controllable power supply circuit is used to control the working state of the oscillator circuit under the control of the control circuit.

[0011] Optionally, the oscillator circuit comprises:

[0012] An operational amplifier chip, wherein the output end of the operational amplifier chip is connected to the input end of the control circuit, and the power supply end of the operational amplifier chip is connected to the output end of the controllable power supply circuit;

[0013] A seventh resistor, a first resistor is connected between the second terminal of the seventh resistor and the ground, and a common node of the seventh resistor and the first resistor is connected to the first input terminal of the operational amplifier chip;

[0014] An eighth resistor, the first terminal of the eighth resistor is connected to the first input terminal of the operational amplifier chip, and the second terminal of the eighth resistor is connected to the output terminal of the operational amplifier chip.

[0015] Optionally, the controllable power supply circuit includes:

[0016] A first switching element, the controlled terminal of the first switching element is connected to the output terminal of the control circuit, the second conducting terminal of the first switching element is grounded, and a fourth resistor is connected in series between the second conducting terminal and the controlled terminal of the first switching element;

[0017] A second switching element, the controlled terminal of the second switching element is connected to the first conducting terminal of the first switching element, the second conducting terminal of the second switching element is grounded, and a fifth resistor is connected in series between the first conducting terminal of the second switching element and the first input terminal of the oscillator circuit;

[0018] A third switching element, a sixth resistor is connected in series between the controlled terminal of the third switching element and the first conducting terminal of the first switching element, the first conducting terminal of the third switching element is used for connecting to a power supply, and the second conducting terminal of the third switching element is connected to the power supply terminal of the oscillator circuit.

[0019] Optionally, the control circuit includes:

[0020] A counting circuit, the input terminal of the counting circuit is connected to the output terminal of the oscillator circuit, the counting circuit is used for counting the number of oscillation signals output by the oscillator circuit, and when the number threshold is reached, a counting signal is output;

[0021] A power supply controller, the input terminal of the power supply controller is connected to the output terminal of the counting circuit, the output terminal of the power supply controller is connected to the controlled terminal of the oscillator circuit, and the power supply controller is used for controlling the working state of the oscillator circuit according to the counting signal.

[0022] Optionally, the counting circuit includes:

[0023] A counter, the input terminal of the counter is connected to the output terminal of the controllable oscillator circuit, the output terminal of the counter is connected to the input terminal of the power supply controller, and the counter is used for counting the number of oscillation signals output by the controllable oscillator circuit, and when the number threshold is reached, a counting signal is output.

[0024] Optionally, an anti-stop oscillation circuit is connected in series between the detection channel and the input end of the controllable oscillator circuit;

[0025] The anti-vibration stop circuit comprises:

[0026] A first capacitor is arranged in series between the detection channel and an input end of the controllable oscillator circuit.

[0027] Optionally, the input end of the controllable oscillator circuit is connected to a clamping circuit.

[0028] Optionally, the clamping circuit comprises:

[0029] a first diode, wherein an anode of the first diode is grounded, and a cathode of the first diode is connected to an input end of the controllable oscillator circuit;

[0030] A second diode, wherein the cathode of the second diode is used to be connected to a power supply, and the anode of the second diode is connected to the input end of the controllable oscillator circuit.

[0031] In addition, to achieve the above-mentioned purpose, the utility model also provides a liquid level detection device, including a host computer and the liquid level detection circuit as described above, the control end of the host computer is electrically connected to the controlled ends of multiple controllable oscillator circuits respectively, and the host computer is used to output a detection start signal to the corresponding controllable oscillator circuit in time sequence.

[0032] The embodiment of the utility model is provided with multiple detection channels, and controllable oscillator circuits are set one by one. The detection channels are used to access external detection signals, and the controllable oscillator circuits are started in turn in time sequence according to the detection start signal to access the external detection signal for detection, so as to solve the mutual interference problem during multi-channel parallel detection. Each detection channel is independently controlled by the corresponding controllable oscillator circuit, thereby ensuring that each channel does not interfere with each other during the detection process, thereby improving the accuracy and reliability of the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0034] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 It is a circuit block diagram of a liquid level detection circuit according to an embodiment of the present utility model;

[0036] Figure 2 It is a circuit block diagram of a liquid level detection circuit according to another embodiment of the present utility model;

[0037] Figure 3 It is a circuit block diagram of a liquid level detection circuit according to still another embodiment of the present utility model;

[0038] Figure 4 It is a circuit block diagram of a liquid level detection circuit according to yet another embodiment of the present utility model;

[0039] Figure 5 It is a circuit block diagram of a liquid level detection circuit according to still another embodiment of the present utility model;

[0040] Figure 6 It is a circuit schematic diagram of a channel in the liquid level detection circuit of the present utility model;

[0041] Figure 7 It is a circuit block diagram of a liquid level detection device according to an embodiment of the present utility model.

[0042] Explanation of the reference numerals in the drawings:

[0043] 10 - Detection channel;

[0044] 20 - Controllable oscillator circuit, 21 - Oscillator circuit, 22 - Control circuit, 221 - Counting circuit, 222 - Power supply controller, 23 - Controllable power supply circuit;

[0045] 30 - Anti-stop oscillation circuit;

[0046] 40 - Clamping circuit;

[0047] 50 - Host computer.

[0048] The realization, functional features and advantages of the object of the present utility model will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific embodiments

[0049] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Well-known modules, units, and their connections, links, communications, or operations are not shown or not described in detail. Moreover, the described features, architectures, or functions can be combined in any manner in one or more embodiments. Those skilled in the art should understand that the following various embodiments are only used for illustration, rather than for limiting the protection scope of the present utility model. It can also be easily understood that the modules, units, or processing methods in the various embodiments described herein and shown in the drawings can be combined and designed in various different configurations. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present utility model.

[0050] For the definitions of various nouns or methods referred to in the following embodiments, unless it is logically impossible, the nouns or methods generally refer to the broad concepts that can be implemented on the premise of the content disclosed in the embodiments. Under such an understanding, all specific subordinate specific definitions of the nouns or methods should be regarded as the content of the present utility model of the present utility model, and should not be narrowly understood or prejudicially interpreted on the grounds that the specific definition is not disclosed in the specification. Similarly, on the premise that it can be logically implemented, the order of the steps in the method is flexible and variable, and all specific subordinate specific definitions in the broad concepts of various nouns or methods belong to the protection scope of the present utility model.

[0051] The main solution of the embodiment of the present application is: by providing multiple detection channels, and setting a controllable oscillator circuit one by one, the detection channel is used to access the external detection signal, and the controllable oscillator circuit is started in turn according to the control signal in time sequence to access the external detection signal for detection. By changing the oscillator of capacitance detection to a controllable oscillator circuit, the controllable oscillator circuit is turned on during detection, and the controllable oscillator circuit is turned off after the detection is completed. When not detecting, the controllable oscillator circuit does not work. In order to avoid mutual interference between multiple channels during simultaneous detection, different channels themselves are used for time-sharing detection, and different address nodes are set for each channel of multiple channels, such as 0X01, 0X02, etc., wherein a channel detection time is t1, and a host computer or an external control signal can be accessed. When receiving the detection command, the 0X01 node channel is detected first, the 0X02 node detection delay t1 is detected, and the 0X03 node is detected after a delay of 2*t1, and the other nodes are similarly scanned. The total time t of each cycle scanning detection is equal to the number of channels multiplied by the detection time t1 of each channel. During the time t, only one pump is performing capacitance detection, and the controllable oscillator circuits of the detection channels that are not detecting are all turned off, thereby avoiding crosstalk from other non-detection channels to the current detection channel, and realizing time-sharing and rotation detection during multi-channel detection, thereby solving the problem of mutual interference during multi-channel detection.

[0052] In the prior art multi-channel liquid level detection equipment, mutual interference is very likely to occur during parallel detection. Such interference directly affects the accuracy of the detection results, may cause a significant increase in errors, and even lead to false detection, which poses a huge challenge to the overall detection efficiency and reliability.

[0053] The present application provides a solution to solve the mutual interference problem during multi-channel parallel detection. Each detection channel is independently controlled by a corresponding controllable oscillator circuit, thereby ensuring that each channel does not interfere with each other during the detection process, thereby improving the accuracy and reliability of the detection results.

[0054] Reference Figure 1 In one embodiment of the present utility model, the liquid level detection circuit includes a plurality of detection channels 10 and a plurality of controllable oscillator circuits 20 arranged correspondingly, wherein:

[0055] The detection channel 10 is used to access the external detection signal; multiple controllable oscillator circuits 20 are connected to the multiple detection channels 10 in a one-to-one correspondence; the controllable oscillator circuits 20 are used to start in turn in time sequence according to the detection start signal to access the external detection signal for detection.

[0056] In the present embodiment, the detection channel 10 is realized by a capacitive sensor, and each sensor can sense the change of the liquid level and generate a corresponding detection signal. The capacitive sensor has the characteristics of high sensitivity and strong anti-interference ability, and is suitable for multi-channel parallel detection. Multiple detection channels 10 are connected to the external detection signal through their respective capacitive sensors. The output signal of each capacitive sensor is sent to the corresponding controllable oscillator circuit 20. The controllable oscillator circuit 20 is started in turn according to the detection start signal in a time sequence to connect the external detection signal for detection. This time separation method ensures that the channels do not interfere with each other during the detection process, thereby improving the accuracy and reliability of the detection results. Among them, the detection channel 10 is a test probe.

[0057] The controllable oscillator circuit 20 can be implemented by an operational amplifier chip U21, a comparison chip or an RC network. When the capacitive sensor senses a change in the liquid level, its capacitance value changes accordingly, resulting in a change in the oscillation frequency. By detecting the change in the oscillation frequency, the height of the liquid level can be accurately determined. In order to improve the detection accuracy, each controllable oscillator circuit 20 can also be equipped with a microprocessor for accurately measuring and processing the oscillation frequency.

[0058] It can be understood that the controllable oscillator circuit 20 can be provided with a main controller for realizing the detection function of starting in turn according to the detection start signal in a time sequence to access the external detection signal, such as MCU (Microcontroller Unit), DSP (Digital Signal Process), FPGA (Field Programmable Gate Array), SOC (System On Chip), etc.

[0059] In order to improve the performance of the liquid level detection circuit, each controllable oscillator circuit 20 can be configured as an oscillator with an adjustable frequency. By adjusting the oscillation frequency, the response speed and sensitivity of the detection signal can be optimized to adapt to different detection environments and requirements.

[0060] In this embodiment, when the detection starts, the probe is not in contact with the liquid surface and there is a certain distance. When the probe reaches the liquid surface, one or more detections in the air have been completed. When the current value is greater than the previous value and is greater than the set threshold, it is determined that the probe is in contact with the liquid surface.

[0061] In this embodiment, a plurality of detection channels 10 are provided, and controllable oscillator circuits 20 are arranged one by one. The detection channels 10 are used to access external detection signals, and the controllable oscillator circuits 20 are started in turn in time sequence according to the detection start signal to access the external detection signal for detection, so as to solve the mutual interference problem during multi-channel parallel detection. Each detection channel 10 is independently controlled by the corresponding controllable oscillator circuit 20, thereby ensuring that each channel does not interfere with each other during the detection process, thereby improving the accuracy and reliability of the detection result.

[0062] Optionally, refer to Figure 2 Another embodiment of the present invention provides a liquid level detection circuit, based on the above Figure 1 In the embodiment shown, the controllable oscillator circuit 20 includes an oscillator circuit 21, a control circuit 22 and a controllable power supply circuit 23, wherein:

[0063] The input end of the oscillator circuit 21 is connected to the corresponding detection channel 10, and the oscillator circuit 21 is used to convert the external probe signal into an oscillation signal of a specific frequency; the control circuit 22 is electrically connected to the oscillator circuit 21, and the control circuit 22 is used to output a corresponding control signal according to the oscillation signal; the output end of the controllable power supply circuit 23 is connected to the power supply end of the oscillator circuit 21, and the controlled end of the controllable power supply circuit 23 is connected to the output end of the control circuit 22, and the controllable power supply circuit 23 is used to control the working state of the oscillator circuit 21 under the control of the control circuit 22.

[0064] In this embodiment, the oscillator circuit 21 converts the external detection signal into an oscillation signal of a specific frequency. The frequency change of the oscillation signal can reflect the detected change in the liquid level. The function of the control circuit 22 is to analyze the oscillation signal and output a corresponding control signal according to the analysis result to adjust the working state of the controllable oscillator circuit 20. The controllable power supply circuit 23 can dynamically adjust the power supply state of the oscillator circuit 21 according to the output signal of the control circuit 22. When detection is required, the controllable power supply circuit 23 provides a stable power supply for the oscillator circuit 21 to ensure the normal operation of the oscillator circuit 21; and when detection is not required, the controllable power supply circuit 23 can cut off the power supply to close the corresponding detection channel 10.

[0065] Optionally, the control circuit 22 can be implemented using a main controller, such as an MCU (Micro controller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System On Chip), etc.

[0066] Optionally, referring to Figure 6 , another embodiment of the present utility model provides a liquid level detection circuit. Based on the above Figure 2 shown embodiment, the oscillator circuit 21 includes an operational amplifier chip U21, a seventh resistor R16, and an eighth resistor R19, where:

[0067] The output end of the operational amplifier chip U21 is connected to the input end of the control circuit 22, and the power supply end of the operational amplifier chip U21 is connected to the output end of the controllable power supply circuit 23; a first resistor R26 is connected between the second end of the seventh resistor R16 and the ground, and the common node of the seventh resistor R16 and the first resistor R26 is connected to the non-inverting input end of the operational amplifier chip U21; the first end of the eighth resistor R19 is connected to the non-inverting input end of the operational amplifier chip U21, and the second end of the eighth resistor R19 is connected to the output end of the operational amplifier chip U21.

[0068] In this embodiment, the non-inverting input end of the operational amplifier chip U21 is provided with a bias voltage by voltage division of the seventh resistor R16 and the first resistor R26, and the eighth resistor R19 is a positive feedback between the output end and the non-inverting input end of the operational amplifier chip U21.

[0069] In this embodiment, the operational amplifier chip U21 forms an oscillation loop through a combination of resistors and the input capacitance of the detection channel 10. When detecting, the control power supply is turned on, and the voltage divided by the seventh resistor R16 and the first resistor R26 is input to the non-inverting input end of U21. At this time, the non-inverting input voltage of the operational amplifier chip U21 is higher than the inverting input end, and the output end of the operational amplifier chip U21 outputs a high level. The output end of the operational amplifier chip U21 charges the capacitor at the inverting end of the operational amplifier chip U21 through the ninth resistor R22. When the voltage of the capacitor at the inverting end of the operational amplifier chip U21 is charged higher than the voltage at the non-inverting end of the operational amplifier chip U21, the operational amplifier chip U21 outputs a low level. Thereafter, the capacitor discharges through the ninth resistor R22. When the voltage is lower than the voltage at the non-inverting end, the operational amplifier chip U21 flips and outputs a high level again and repeats the cycle, enabling the operational amplifier chip U21 to generate a stable oscillation signal. When the liquid level signal changes are sensed by the detection channel 10, the change in the capacitance value of the capacitive sensor will affect the oscillation frequency through the second resistor R27, thereby changing the signal frequency at the output end of the operational amplifier chip U21.

[0070] Optionally, referring to Figure 6 , still another embodiment of the present utility model provides a liquid level detection circuit. Based on the above Figure 2 shown embodiment, the controllable power supply circuit 23 includes a first switching element Q2, a second switching element Q4, and a third switching element Q1, where:

[0071] The controlled end of the first switch element Q2 is connected to the output end of the control circuit 22, the second conduction end of the first switch element Q2 is grounded, and a fourth resistor R3 is connected in series between the second conduction end and the controlled end of the first switch element Q2; the controlled end of the second switch element Q4 is connected to the first conduction end of the first switch element Q2, the second conduction end of the second switch element Q4 is grounded, and a fifth resistor R34 is connected in series between the first conduction end of the second switch element Q4 and the first input end of the oscillator circuit 21; a sixth resistor R9 is connected in series between the controlled end of the third switch element Q1 and the first conduction end of the first switch element Q2, the first conduction end of the third switch element Q1 is used to connect to the power supply, and the second conduction end of the third switch element Q1 is connected to the power supply end of the oscillator circuit 21.

[0072] In this embodiment, the first switch element Q2, the second switch element Q4 and the third switch element Q1 can all be transistors, field effect transistors (FETs) or other types of switch elements. The first switch element Q2 is used as a simple control switch, and its conduction state is determined by the control circuit 22. When the first switch element Q2 is turned on, the second switch element Q4 is turned off and the third switch element Q1 is turned on, thereby providing power for the oscillator circuit 21. The fourth resistor R3 pulls down to stabilize the switch state, and the fifth resistor R34 and the sixth resistor R9 are respectively used to limit the current passing through the switch element to protect the switch element from excessive current shock. When the control circuit 22 outputs a high level signal, the first switch element Q2 is turned on, the second switch element Q4 is turned off, and the third switch element Q1 is turned on accordingly, and the oscillator circuit 21 obtains power and starts working. When the control circuit 22 outputs a low level, the first switch element Q2 is turned off, the second switch element Q4 is turned on, so that the oscillator ends the oscillation state, and the third switch element Q1 is also turned off accordingly, and the oscillator circuit 21 stops working. In this way, the controllable power supply circuit 23 can accurately control the working state of the oscillator circuit 21 according to the instructions of the control circuit 22, thereby realizing precise control of the liquid level detection circuit to achieve a liquid level detection function with high precision, high stability and high reliability.

[0073] Optionally, refer to Figure 3 Another embodiment of the present invention provides a liquid level detection circuit, based on the above Figure 2 In the embodiment shown, the control circuit 22 includes a counting circuit 221 and a power controller 222, wherein:

[0074] The input terminal of the counting circuit 221 is connected to the output terminal of the oscillator circuit 21. The counting circuit 221 is used to count the number of oscillation signals output by the oscillator circuit 21 and output a counting signal when the number threshold is reached. The input terminal of the power supply controller 222 is connected to the output terminal of the counting circuit 221, and the output terminal of the power supply controller 222 is connected to the controlled terminal of the oscillator circuit 21. The power supply controller 222 is used to control the working state of the oscillator circuit 21 according to the counting signal.

[0075] In this embodiment, the function of the counting circuit 221 is to monitor the number of oscillation signals generated by the oscillator circuit 21. When the preset number threshold is reached, for example, 16 oscillation pulse signals, the counting circuit 221 will output a counting signal. This counting signal is transmitted to the power supply controller 222, and the power supply controller 222 controls the working state of the oscillator circuit 21 according to the received counting signal. For example, when the counting signal indicates that enough data points have been detected, the power supply controller 222 can instruct the controllable power supply circuit 23 to reduce the power supply to the oscillator circuit 21, thereby reducing power consumption; or completely cut off the power under specific conditions to save energy.

[0076] The power supply controller 222 can be designed to have multiple working modes, such as normal working mode, low power consumption mode, and sleep mode. In the normal working mode, the oscillator circuit 21 operates at full power to ensure the accuracy of liquid level detection. In the low power consumption mode, the power supply to the oscillator circuit 21 is reduced, but still maintains enough energy to maintain the basic detection function. In the sleep mode, the power supply to the oscillator circuit 21 is completely cut off, and the power supply controller 222 will not activate the controllable power supply circuit 23 until the next detection is required, and the oscillator circuit 21 will start working again.

[0077] In addition, the power supply controller 222 can also adjust the working state of the oscillator circuit 21 according to external control signals or the instructions of a timer. For example, if the liquid level detection system is set to perform detection regularly, the power supply controller 222 can activate the oscillator circuit 21 according to the timing result of the timer and cut off the power again after the detection task is completed.

[0078] Optionally, referring to Figure 6 , another embodiment of the present invention provides a liquid level detection circuit. Based on the above Figure 3 shown embodiment, the counting circuit 221 includes a counter U2, where:

[0079] The input terminal of the counter U2 is connected to the output terminal of the controllable oscillator circuit 20, and the output terminal of the counter U2 is connected to the input terminal of the power supply controller 222. The counter U2 is used to count the number of oscillation signals output by the controllable oscillator circuit 20 and output a counting signal when the number threshold is reached.

[0080] In this embodiment, the counter U2 can be designed using digital circuits. For example, an integrated circuit (IC) counter U2 or a counter U2 module built into a microcontroller can be used. The counting range and speed of the counter U2 can be selected and adjusted according to the actual application requirements. For example, to improve the detection accuracy, a counter U2 with a higher counting speed can be selected to accurately record the number of high-frequency oscillation signals.

[0081] Optionally, the counter U2 is selected as a dual-channel 4-bit binary counter U2. The first output 1Q3 of the counter U2 is output to the clock input of the second-channel counter U2, and the output signal is composed of the second output 2Q1 to form a 16-bit counter U2. That is, after the oscillator circuit 21 outputs 16 pulses, it outputs one pulse to the main controller to stop timing, and the time corresponding to 16 oscillation periods is obtained.

[0082] Optionally, the counting threshold setting of the counter U2 can be achieved through hardware jumpers, software programming, or external control signals. In some applications, in order to adapt to different detection environments and requirements, the counting threshold may need to be dynamically adjusted. For example, in an environment where the liquid level changes rapidly, a lower counting threshold can be set to improve the response speed; while in an environment where the liquid level changes slowly, a higher counting threshold can be set to reduce power consumption.

[0083] The counting signal output by the counter U2 can be a digital signal or a pulse signal. In the case of a digital signal, the counter U2 can directly output the count value in binary form to the power controller 222. In the case of a pulse signal, the counter U2 can output one or more pulse signals when the counting threshold is reached, and the power controller 222 determines whether to adjust the working state of the oscillator circuit 21 according to the number and frequency of the pulse signals.

[0084] To ensure the stability and reliability of the liquid level detection circuit, the counting circuit 221 can also include an anti-jitter circuit to eliminate false counting caused by noise or interference. The anti-jitter circuit can be implemented using a hardware filter or a software algorithm to ensure that the counter U2 only counts valid oscillation signals.

[0085] Optionally, referring to Figure 4 , another embodiment of the present invention provides a liquid level detection circuit. Based on any of the above Figures 1 to 3 or Figure 6 shown embodiments, an anti-stop oscillation circuit 30 is connected in series between the detection channel 10 and the input end of the controllable oscillator circuit 20.

[0086] In this embodiment, when multi-channel detection is performed, if the conductivity of the liquid to be measured is good and the impedance formed between the needles is small, the charging voltage at the inverting terminal of the operational amplifier chip U21 may not reach the flip voltage and the oscillator may not start. Therefore, an anti-stop oscillation circuit 30 is connected in series between the inverting terminal and the probe to prevent the above situation. The function of the anti-stop oscillation circuit 30 is to ensure that during the liquid level detection process, the oscillator circuit 21 can work continuously and stably, and avoid the stop oscillation phenomenon caused by external interference or circuit faults. The anti-stop oscillation circuit 30 may include one or more filters, voltage regulators, and protection components to ensure that the input signal of the oscillator circuit 21 is stable and interference-free.

[0087] The anti-stop oscillation circuit 30 may include a low-pass filter for filtering high-frequency noise to prevent such noise from having an adverse effect on the oscillator circuit 21. In addition, the anti-stop oscillation circuit 30 may also include a voltage regulator to ensure that the oscillator circuit 21 can still obtain stable power supply when the power supply voltage fluctuates. In some cases, the anti-stop oscillation circuit 30 may also include overvoltage protection and short-circuit protection components to prevent damage caused by abnormal external voltage or circuit short-circuit.

[0088] Optionally, the anti-stop oscillation circuit 30 includes a first capacitor C3, where:

[0089] The first capacitor C3 is connected in series between the detection channel 10 and the input terminal of the controllable oscillator circuit 20.

[0090] In this embodiment, the function of the first capacitor C3 is to provide a low-impedance path for high-frequency signals to pass through smoothly while blocking the interference of DC components. By selecting an appropriate capacitance value, it can be ensured that the oscillator circuit 21 obtains the best signal transmission effect within the normal operating frequency range. The capacitance of the first capacitor C3 is selected such that when the probe is grounded, the time of 16 oscillation cycles does not exceed the maximum timing time of the main controller. Avoiding the capacitance of the detection being too large and exceeding the range of the microcontroller timer can effectively avoid the stop oscillation phenomenon caused by external interference or circuit faults and ensure that the liquid level detection circuit can work stably and reliably in various environments.

[0091] Optionally, referring to Figure 5 , another embodiment of the present invention provides a liquid level detection circuit. Based on any of the above Figures 1 to 3 or Figure 6 shown embodiments, a clamping circuit 40 is connected to the input terminal of the controllable oscillator circuit 20.

[0092] In this embodiment, the function of the clamping circuit 40 is to limit the voltage range at the input terminal of the controllable oscillator circuit 20 to prevent excessive voltage from damaging circuit components. The clamping circuit 40 may include one or more diodes, zener diodes, or clamping diodes to ensure that the input voltage is within a safe range.

[0093] The clamping circuit 40 can be set to forward clamping and reverse clamping to limit the peak voltages in the forward and reverse directions respectively. For example, for forward clamping, a zener diode can be used. When the input voltage exceeds the zener voltage of the zener diode, the zener diode conducts and limits the voltage below the zener voltage. For reverse clamping, an ordinary diode can be used. When the input voltage is negative, the diode conducts and limits the voltage below zero volts.

[0094] Optionally, the clamping circuit 40 can include a clamping resistor, which is serially arranged with the clamping diode. The function of the clamping resistor is to limit the current of the clamping diode and prevent excessive current from damaging the diode. The resistance value of the clamping resistor can be selected according to the requirements of the actual circuit to ensure that the clamping circuit 40 can work properly under various conditions.

[0095] Optionally, referring to Figure 6 , another embodiment of the present utility model provides a liquid level detection circuit. Based on the above Figure 5 shown embodiment, the clamping circuit 40 includes a first diode D6 and a second diode D5, where:

[0096] The positive electrode of the first diode D6 is grounded, and the negative electrode of the first diode D6 is connected to the input end of the controllable oscillator circuit 20; the negative electrode of the second diode D5 is used to connect to the power supply, and the positive electrode of the second diode D5 is connected to the input end of the controllable oscillator circuit 20.

[0097] In this embodiment, through the combination of the first diode D6 and the second diode D5 in the clamping circuit 40, the clamping circuit 40 can effectively limit the voltage range at the input end and prevent excessive forward or reverse voltage from damaging the oscillator circuit 21.

[0098] The first diode D6 acts as reverse clamping. When a negative voltage appears at the input end, the diode conducts and limits the negative voltage below zero volts, thereby protecting the oscillator circuit 21 from the influence of reverse voltage. The second diode D5 acts as forward clamping. When the input end voltage exceeds its forward conduction voltage, the diode conducts and limits the voltage within a safe range to avoid damage to circuit components caused by excessive forward voltage.

[0099] As Figure 7 shown, in an embodiment of the present utility model, the present utility model also proposes a liquid level detection device. The liquid level detection device includes a host computer 50 and a liquid level detection circuit as in the above embodiment. The control end of the host computer 50 is electrically connected to the controlled ends of a plurality of controllable oscillator circuits 20 respectively, and the host computer 50 is used to output detection start signals to the corresponding controllable oscillator circuits 20 in chronological order.

[0100] It should be noted that since the liquid level detection device of the present utility model is based on the above-mentioned liquid level detection circuit, therefore, the embodiments of the liquid level detection device of the present utility model include all the technical solutions of all the embodiments of the above-mentioned liquid level detection circuit, and the achieved technical effects are also exactly the same, which will not be elaborated here.

[0101] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or system including that element.

[0102] The serial numbers of the above embodiments of the present utility model are only for description and do not represent the advantages or disadvantages of the embodiments.

[0103] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present utility model, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium as described above (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to enable a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present utility model.

[0104] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present utility model.

Claims

1. A liquid level detection circuit, characterized in that, The liquid level detection circuit comprises: A plurality of detection channels, wherein the detection channels are used to access external detection signals; A plurality of controllable oscillator circuits are connected to the plurality of detection channels in a one-to-one correspondence; the controllable oscillator circuits are used to start in turn in a time sequence according to a detection start signal to access an external detection signal for detection.

2. The liquid level detection circuit according to claim 1, wherein The controllable oscillator circuit comprises: an oscillator circuit, wherein an input end of the oscillator circuit is connected to the corresponding detection channel, and the oscillator circuit is used to convert the external detection signal into an oscillation signal of a specific frequency; A control circuit, the control circuit being electrically connected to the oscillator circuit, and the control circuit being configured to output a corresponding control signal according to the oscillation signal; A controllable power supply circuit, wherein the output end of the controllable power supply circuit is connected to the power supply end of the oscillator circuit, the controlled end of the controllable power supply circuit is connected to the output end of the control circuit, and the controllable power supply circuit is used to control the working state of the oscillator circuit under the control of the control circuit.

3. The liquid level detection circuit according to claim 2, wherein The oscillator circuit comprises: An operational amplifier chip, wherein the output end of the operational amplifier chip is connected to the input end of the control circuit, and the power supply end of the operational amplifier chip is connected to the output end of the controllable power supply circuit; a seventh resistor, wherein a first resistor is connected between a second end of the seventh resistor and ground, and a common node of the seventh resistor and the first resistor is connected to a first input end of the operational amplifier chip; An eighth resistor, wherein a first end of the eighth resistor is connected to the first input end of the operational amplifier chip, and a second end of the eighth resistor is connected to the output end of the operational amplifier chip.

4. The liquid level detection circuit according to claim 2, characterized in that, The controllable power supply circuit comprises: a first switch element, wherein a controlled end of the first switch element is connected to an output end of the control circuit, a second conducting end of the first switch element is grounded, and a fourth resistor is connected in series between the second conducting end and the controlled end of the first switch element; a second switch element, wherein a controlled end of the second switch element is connected to a first conduction end of the first switch element, a second conduction end of the second switch element is grounded, and a fifth resistor is connected in series between the first conduction end of the second switch element and the first input end of the oscillator circuit; A third switch element, a sixth resistor is connected in series between the controlled end of the third switch element and the first conduction end of the first switch element, the first conduction end of the third switch element is used to access the power supply, and the second conduction end of the third switch element is connected to the power supply end of the oscillator circuit.

5. The liquid level detection circuit according to claim 2, wherein The control circuit comprises: a counting circuit, wherein an input end of the counting circuit is connected to an output end of the oscillator circuit, and the counting circuit is used to count the number of oscillation signals output by the oscillator circuit, and output a counting signal when a number threshold is reached; A power controller, wherein the input end of the power controller is connected to the output end of the counting circuit, the output end of the power controller is connected to the controlled end of the oscillator circuit, and the power controller is used to control the working state of the oscillator circuit according to the counting signal.

6. The liquid level detection circuit according to claim 5, wherein, The counting circuit comprises: A counter, the input end of the counter is connected to the output end of the controllable oscillator circuit, the output end of the counter is connected to the input end of the power controller, and the counter is used to count the number of oscillation signals output by the controllable oscillator circuit and output a count signal when the number threshold is reached.

7. The liquid level detection circuit according to any one of claims 1 to 6, characterized in that, An anti-stop oscillation circuit is connected in series between the detection channel and the input end of the controllable oscillator circuit; The anti-stop oscillation circuit includes: A first capacitor, the first capacitor is serially arranged between the detection channel and the input end of the controllable oscillator circuit.

8. The liquid level detection circuit according to any one of claims 1 to 6, characterized in that, A clamping circuit is connected to the input end of the controllable oscillator circuit.

9. The liquid level detection circuit according to claim 8, wherein The clamping circuit includes: A first diode, the positive electrode of the first diode is grounded, and the negative electrode of the first diode is connected to the input end of the controllable oscillator circuit; A second diode, the negative electrode of the second diode is used to connect to the power supply, and the positive electrode of the second diode is connected to the input end of the controllable oscillator circuit.

10. A liquid level detection device, characterized in that, It includes a host computer and the liquid level detection circuit according to any one of claims 1 to 9. The control end of the host computer is electrically connected to the controlled ends of a plurality of the controllable oscillator circuits respectively, and the host computer is used to output a detection start signal to the corresponding controllable oscillator circuit in chronological order.

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