Filter circuit, chip and electronic equipment

Abstract

The utility model provides a filter circuit, a chip and electronic equipment, and the filter circuit comprises a filter module which comprises a filter capacitor and a filter resistor; the output end of the common-mode bias module is connected with the filtering module so as to bias an output signal output by the second end of the filtering capacitor at the common-mode voltage; the driving module is used for outputting starting current, and the output end of the driving module is connected with the filtering module; wherein in the process that the voltage of the second end of the filter capacitor rises to the common-mode voltage, the driving module inputs starting current to the second end of the filter capacitor so as to accelerate the voltage of the second end of the filter capacitor to rise to the common-mode voltage. The voltage of the second end of the filter capacitor can be quickly increased to the common-mode voltage through the driving module, so that the establishment speed of the common-mode voltage of the filter module is increased, and finally the measurement speed of the signal is ensured.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a filtering circuit, a chip and an electronic device. Background Art

[0002] At present, when processing dynamic signals containing DC components, a high-pass filter is often used to filter out the DC components, and then a bias circuit is used to bias the dynamic signal at a common-mode voltage to facilitate processing by the signal processing circuit. However, biasing the dynamic signal at a common-mode voltage requires charging the capacitor of the high-pass filter. When the resistance and / or capacitance of the high-pass filter is large, the charging speed of the capacitor of the high-pass filter is slow, which leads to a slow establishment speed of the common-mode voltage and thus slows down the signal measurement speed. Utility Model Content

[0003] In view of the above problems, the embodiments of the present application provide a filter circuit, a chip and an electronic device to solve the above technical problems.

[0004] In a first aspect, an embodiment of the present application provides a filter circuit, comprising:

[0005] A filter module, the filter module includes a filter capacitor and a filter resistor, the first end of the filter capacitor is connected to the input signal, the second end of the filter capacitor is connected to the first end of the filter resistor, the second end of the filter resistor is connected to the ground end, and the second end of the filter capacitor outputs the filtered output signal;

[0006] A common mode bias module for outputting a common mode voltage, wherein an output end of the common mode bias module is connected to the filter module to bias an output signal outputted from the second end of the filter capacitor at the common mode voltage;

[0007] A driving module for outputting a starting current, wherein an output end of the driving module is connected to the filtering module;

[0008] When the voltage at the second end of the filter capacitor rises to the common mode voltage, the driving module inputs a starting current to the second end of the filter capacitor, so that the voltage at the second end of the filter capacitor rises quickly to the common mode voltage.

[0009] In a second aspect, the present application provides a chip, comprising the filter circuit as described in the first aspect.

[0010] In a third aspect, the present application provides an electronic device comprising the chip as described in the second aspect.

[0011] The present application outputs a common-mode voltage through a common-mode bias module, and the common-mode bias module can bias the second end of the filter capacitor at the common-mode voltage. In the process of the voltage at the second end of the filter capacitor rising to the common-mode voltage, the driving module inputs a starting current to the second end of the filter capacitor. Therefore, the driving module can make the voltage at the second end of the filter capacitor rise quickly to the common-mode voltage, thereby improving the common-mode voltage establishment speed of the filter module and ultimately ensuring the signal measurement speed.

[0012] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 A schematic diagram of a signal processing circuit in the related art is shown.

[0015] Figure 2 A schematic diagram of a filter circuit in an embodiment of the present application is shown.

[0016] Figure 3 A circuit diagram of a filter circuit in an embodiment of the present application is shown.

[0017] Figure 4 Another schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0018] Figure 5 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0019] Figure 6 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0020] Figure 7 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0021] Figure 8 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0022] Fig. 9 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0023] Fig.10 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0024] Fig.11 Another schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0025] Fig.12 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0026] Fig.13 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0027] Fig.14 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0028] Fig.15 Another circuit schematic diagram of the filter circuit in the embodiment of the present application is shown.

[0029] Among them, 10 is a filter module, 20 is a common mode bias module, 30 is a drive module, and 40 is a detection module;

[0030] Filter capacitor C0, filter resistor R0, input signal Vin, output signal Vout, first node M1, second node M2, common mode voltage Vcm, startup current I0, first operational amplifier OP1, first switch S1, first comparator COMP, first resistor R1, second resistor R2, third resistor R3, second switch S2, fourth resistor R4, first capacitor C1. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0032] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0033] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0034] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0035] In the description of the embodiments of the present application, words such as "example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "example" or "for example" in the embodiments of the present application is not to be interpreted as being more preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to present relative concepts in a clear manner.

[0036] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0037] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0038] The first pole / first end and the second pole / second end of the electronic element (such as a resistor or a capacitor) used in the embodiments of the present application are symmetrical in structure, so the first pole / first end and the second pole / second end may be structurally indistinguishable. For example, when the electronic element is a capacitor, the first end and the second end of the capacitor refer to one end connected to the plate on one side of the capacitor and the other end connected to the plate on the other side of the capacitor, respectively; when the electronic element is a resistor, the first end of the resistor refers to any one of its two ends, and the second end of the resistor refers to the other end of the two ends.

[0039] In the circuit structure provided in the embodiments of the present application, the first node, the second node and other nodes do not represent actual existing components, but represent the junction points of related couplings in the circuit diagram, that is, these nodes are nodes formed by the equivalent junction points of related couplings in the circuit diagram.

[0040] At present, when processing dynamic signals containing DC components, it is often necessary to use a high-pass filter to filter out the DC components, and then use a bias circuit to bias the dynamic signal to a common mode voltage to facilitate processing by the signal processing circuit. Figure 1 , Figure 1 A schematic diagram of a signal processing circuit in the related art is shown. The capacitor C connected to the signal source Vin and the resistor R connected to the ground terminal form a high-pass filter. The high-pass filter filters out the DC component of the signal source Vin and biases the dynamic signal at the common mode voltage Vcm through the bias circuit. Then, the output signal of the high-pass filter is measured by the analog-to-digital converter inside the chip.

[0041] For example, if the voltage fluctuation range of the dynamic signal is 10V~15V, and the DC component it contains is 12.5V, and the input range of the analog-to-digital converter is 0V~5V, then a high-pass filter is needed to filter out the DC component and bias the voltage of the dynamic signal at a common-mode voltage of 2.5V, that is, the voltage fluctuation range of the dynamic signal output by the high-pass filter is changed to 0V~5V, so that the dynamic signal matches the input range of the analog-to-digital converter, ensuring that the analog-to-digital converter can measure the dynamic signal normally.

[0042] However, biasing the dynamic signal at the common-mode voltage requires charging the capacitor of the high-pass filter. When the resistance and / or capacitance of the high-pass filter is large, the charging speed of the capacitor of the high-pass filter is slow, which leads to the technical problem that the common-mode voltage is slow to establish and thus slows down the signal measurement speed.

[0043] To this end, the present application provides a filtering circuit, a chip and an electronic device, which are described in detail below.

[0044] First, see Figure 2 , Figure 2 A schematic diagram of a filter circuit in an embodiment of the present application is shown, wherein the filter circuit includes a filter module 10, a common-mode bias module 20 for outputting a common-mode voltage Vcm, and a drive module 30 for outputting a starting current I0.

[0045] Specifically, the filter module 10 can filter out the DC component in the input signal Vin. For example, if the input signal Vin is a sinusoidal signal, the minimum voltage value during the change of the sinusoidal signal is 10V and the maximum voltage value is 15V. Then, the filter module 10 can filter out the DC component of 12.5V in the input signal Vin, so that the output signal Vout is changed to a sinusoidal signal with a voltage range of -2.5V to 2.5V. The filter module 10 includes a filter capacitor C0 and a filter resistor R0. The first end of the filter capacitor C0 is connected to the input signal Vin, the second end of the filter capacitor C0 is connected to the first end of the filter resistor R0, and the second end of the filter resistor R0 is connected to the ground terminal GND. Since the filter capacitor C0 has the characteristic of passing AC and blocking DC, the first node M1 between the filter capacitor C0 and the filter resistor R0 can output the output signal Vout after the DC component is filtered out.

[0046] Understandably, Figure 2 The circuit structure of the filter module 10 is shown as a first-order high-pass filter circuit, but is not limited thereto. For example, a filter capacitor C0 may be further added to make the filter module 10 form a second-order high-pass filter circuit.

[0047] The common-mode bias module 20 is connected to the filter module 10. The common-mode bias module 20 can bias the output signal Vout outputted from the second end of the filter capacitor C0 at the common-mode voltage Vcm. For example, taking the output signal Vout as a sinusoidal signal with a voltage range of -2.5V to 2.5V as an example, the common-mode bias module 20 can output a common-mode voltage Vcm with a voltage of 2.5V, thereby changing the output signal Vout to a sinusoidal signal with a voltage range of 0V to 5V. Exemplarily, the common-mode bias module 20 can output the common-mode voltage Vcm using a resistor voltage divider circuit, a boost circuit, or a buck voltage, such as a Boost boost circuit or a Buck buck circuit.

[0048] The output end of the driving module 30 is connected to the filtering module 10. The driving module 30 can input the starting current I0 to the second end of the filtering capacitor C0 to accelerate the process of the output signal Vout being biased at the common mode voltage Vcm. For example, the driving module 30 can accelerate the process of changing a sinusoidal signal of -2.5V to 2.5V to a sinusoidal signal of 0V to 5V. As an example, refer to Figure 3 , Figure 3 A circuit schematic diagram of the filter circuit in an embodiment of the present application is shown, and the driving module 30 includes a current source IS and a switch Sc. When the switch Sc is closed, the current source IS can input a starting current I0 to the second end of the filter capacitor C0 to increase the voltage at the second end of the filter capacitor C0, thereby accelerating the process of biasing the output signal Vout at the common mode voltage Vcm.

[0049] In an embodiment of the present application, the present application outputs a common-mode voltage Vcm through a common-mode bias module 20. The common-mode bias module 20 can bias the second end of the filter capacitor C0 at the common-mode voltage Vcm. In the process of the voltage at the second end of the filter capacitor C0 rising to the common-mode voltage Vcm, the driving module 30 inputs a starting current I0 to the second end of the filter capacitor C0. Therefore, the driving module 30 can make the voltage at the second end of the filter capacitor C0 rise quickly to the common-mode voltage Vcm, thereby improving the establishment speed of the common-mode voltage Vcm of the filter module 10, and ultimately ensuring the measurement speed of the signal.

[0050] In some embodiments of the present application, participation Figure 4 , Figure 4 Another schematic diagram of the filter circuit in the embodiment of the present application is shown, wherein the input end of the driving module 30 is connected to the common-mode bias module 20 to access the common-mode voltage Vcm; the output end of the driving module 30 is connected to the second end of the filter capacitor C0, that is, the driving module 30 outputs the starting current I0 to the second end of the filter capacitor C0 according to the common-mode voltage Vcm, and the voltage at the output end of the driving module 30 does not exceed the common-mode voltage Vcm, so it is beneficial to ensure that the voltage at the second end of the filter capacitor C0 does not continue to rise after rising to the common-mode voltage Vcm, thereby avoiding the phenomenon that the voltage at the second end of the filter capacitor C0 is too high and causes the common-mode voltage Vcm to be established. The speed is reduced.

[0051] As an example, see Figure 5 , Figure 5 Another circuit schematic diagram of the filter circuit in an embodiment of the present application is shown, wherein the driving module 30 includes a first operational amplifier OP1, the non-inverting input terminal of the first operational amplifier OP1 is connected to the common-mode bias module 20 to access the common-mode voltage Vcm; the inverting input terminal of the first operational amplifier OP1 is connected to the output terminal of the first operational amplifier OP1, and the output terminal of the first operational amplifier OP1 is connected to the second end of the filter capacitor C0.

[0052] It should be noted that, since the operational amplifier has the virtual short and virtual open characteristics, when the inverting input terminal of the first operational amplifier OP1 is connected to the output terminal of the first operational amplifier OP1, the first operational amplifier OP1 forms a voltage follower with a voltage gain of 1. After the circuit reaches a steady state, the output terminal voltage of the first operational amplifier OP1 will be equal to the voltage of the non-inverting input terminal of the first operational amplifier OP1, that is, the output terminal voltage of the first operational amplifier OP1 will be equal to the common-mode voltage Vcm, thereby ensuring that the voltage at the second end of the filter capacitor C0 will no longer continue to rise after rising to the common-mode voltage Vcm; at the same time, since the voltage follower has a very low output impedance, the voltage follower can output a larger current, so that the voltage at the second end of the filter capacitor C0 quickly rises to the common-mode voltage Vcm.

[0053] In some embodiments of the present application, see Figure 6 , Figure 6 Another circuit diagram of the filter circuit in the embodiment of the present application is shown, wherein the driving module 30 further includes a first switch S1; the first end of the first switch S1 is connected to the second end of the filter capacitor C0, the second end of the first switch S1 is connected to the output end of the first operational amplifier OP1, and the output end of the first operational amplifier OP1 is connected to the second end of the filter resistor R0. Specifically, before the second end of the filter capacitor C0 rises to the common mode voltage Vcm, the first switch S1 is in a closed state, and the filter resistor R0 is bypassed, so that the output impedance of the voltage follower is further reduced, which is conducive to further shortening the time for the voltage at the second end of the filter capacitor C0 to rise to the common mode voltage Vcm; and after the second end of the filter capacitor C0 rises to the common mode voltage Vcm, the first switch S1 is in an open state, the filter resistor R0 works normally, and the output end voltage of the first operational amplifier OP1 clamps the second end of the filter resistor R0 at the common mode voltage Vcm, so that the filter module 10 normally outputs the output signal Vout biased at the common mode voltage Vcm.

[0054] It can be understood that the output end of the first operational amplifier OP1 can also be directly connected to the second end of the filter capacitor C0, and the second end of the filter resistor R0 can be connected to the output end of the common-mode bias module 20. After the second end of the filter capacitor C0 rises to the common-mode voltage Vcm, the power supply of the first operational amplifier OP1 is turned off.

[0055] For example, see Figure 7 , Figure 7 Another circuit diagram of the filter circuit in the embodiment of the present application is shown, the output end of the first operational amplifier OP1 is directly connected to the second end of the filter capacitor C0, and the driving module 30 also includes a second switch S2; the first end of the second switch S2 is connected to the second end of the filter capacitor C0, and the second end of the second switch S2 is connected to the first end of the filter resistor R0. Specifically, before the second end of the filter capacitor C0 rises to the common mode voltage Vcm, the second switch S2 is in an open state, so the first operational amplifier OP1 can quickly input the starting current I0 to the second end of the filter capacitor C0, and make the second end of the filter capacitor C0 quickly rise to the common mode voltage Vcm; after the second end of the filter capacitor C0 rises to the common mode voltage Vcm, the second switch S2 is in a closed state, and the second operational amplifier is enabled and turned off, so that the filter module 10 can normally output the output signal Vout biased at the common mode voltage Vcm.

[0056] In some embodiments of the present application, for example, for an embodiment in which the common mode bias module 20 includes a resistor divider circuit, see Figure 8 or Fig. 9, Figure 8 Another circuit diagram of the filter circuit in the embodiment of the present application is shown. Fig. 9 Another circuit diagram of the filter circuit in the embodiment of the present application is shown, wherein the common-mode bias module 20 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the power supply terminal VDD, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the ground terminal GND. In other words, the first resistor R1 and the second resistor R2 are connected in series between the power supply terminal VDD and the ground terminal GND, so the second node M2 ​​between the first resistor R1 and the second resistor R2 can output the common-mode voltage Vcm.

[0057] In some embodiments of the present application, for example, the driving module 30 further includes a second switch S2. Fig.10 , Fig.10 Another circuit diagram of the filter circuit in the embodiment of the present application is shown, wherein the common-mode bias module 20 includes a third resistor R3; the first end of the third resistor R3 is connected to the power supply terminal VDD, the second end of the third resistor R3 is connected to the first end of the filter resistor R0, and the second end of the second switch S2 is connected to the third node M3 between the third resistor R3 and the filter resistor R0. In other words, the third resistor R3 and the filter resistor R0 are connected in series between the power supply terminal VDD and the ground terminal GND, so the third resistor R3 and the filter resistor R0 generate a common-mode voltage Vcm at the third node M3 between the two after voltage division, so as to provide a common-mode voltage for the in-phase input terminal of the first operational amplifier and achieve the purpose of biasing the output signal Vout at the common-mode voltage Vcm.

[0058] In some embodiments of the present application, see Fig.11 , Fig.11 Another schematic diagram of the filter circuit in the embodiment of the present application is shown, wherein the filter circuit further includes a detection module 40; the input end of the detection module 40 is connected to the second end of the filter capacitor C0 to detect whether the voltage at the second end of the filter capacitor C0 reaches the common mode voltage Vcm, and the output end of the detection module 40 is connected to the drive module 30 to control whether the drive module 30 continues to output the starting current I0. In other words, the detection module 40 can determine whether the voltage at the second end of the filter capacitor C0 reaches the common mode voltage Vcm, and control whether the drive module 30 continues to output the starting current I0, so that after the voltage at the second end of the filter capacitor C0 reaches the common mode voltage Vcm, the drive module 30 is actively controlled to stop outputting the starting current I0, which is beneficial to reducing the power consumption of the filter circuit.

[0059] In some embodiments of the present application, the detection module 40 includes a first comparator COMP; the first input terminal of the first comparator COMP is connected to the second end of the filter capacitor C0, and the second input terminal of the first comparator COMP is connected to the common-mode bias module 20; the output terminal of the first comparator COMP is connected to the driving module 30 to control the driving module 30 to stop outputting the starting current I0 after the second end of the filter capacitor C0 reaches the common-mode voltage Vcm.

[0060] For example, see Fig.12 , Fig.12 Another circuit schematic diagram of the filter circuit in an embodiment of the present application is shown, the first input terminal of the first comparator COMP is directly connected to the second end of the filter capacitor C0, the second input terminal of the first comparator COMP is connected to the second node M2, when the voltage at the second end of the filter capacitor C0 is higher than the common mode voltage Vcm, the first comparator COMP will output a high level signal, thereby controlling the first switch S1 to be disconnected.

[0061] For another example, see Fig.13 , Fig.13 Another circuit schematic diagram of the filter circuit in an embodiment of the present application is shown, the first input end of the first comparator COMP is directly connected to the second end of the filter capacitor C0, the second input end of the first comparator COMP is connected to the third node M3, when the voltage at the second end of the filter capacitor C0 is higher than the common mode voltage Vcm, the first comparator COMP will output a high-level signal, and then can control the second switch S2 to close, and control the first operational amplifier OP1 to power off and stop working, thereby reducing the power consumption of the filter circuit.

[0062] In some embodiments of the present application, see Fig.14 , Fig.14 Another circuit diagram of the filter circuit in the embodiment of the present application is shown, the detection module 40 also includes a first capacitor C1 and a fourth resistor R4; the first end of the fourth resistor R4 is connected to the second end of the filter capacitor C0, the second end of the fourth resistor R4 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the ground terminal GND; the first input end of the first comparator COMP is connected to the fourth node M4 between the first capacitor C1 and the fourth resistor R4. In this way, the first capacitor C1 and the fourth resistor R4 form a low-pass filter, so the fourth node M4 can output the DC component voltage of the second end of the filter capacitor C0, so that the first comparator COMP determines whether the DC component voltage of the second end of the filter capacitor C0 reaches the common mode voltage Vcm.

[0063] In some embodiments of the present application, see Fig.15 , Fig.15A working schematic diagram of the filter circuit in the embodiment of the present application, a third switch S3 can be further set in the filter circuit, and the third switch S3 can control whether the first end of the fourth resistor R4 is connected to the second end of the filter capacitor C0. In the process of the second end of the filter capacitor C0 rising to the common mode voltage Vcm, the third switch S3 is in a closed state, so the first comparator COMP can normally judge whether the DC component voltage of the second end of the filter capacitor C0 reaches the common mode voltage Vcm; after the second end of the filter capacitor C0 rises to the common mode voltage Vcm, the third switch S3 is in an open state, which can stop the first comparator from working on the one hand, and can also prevent the low-pass filter composed of the first capacitor C1 and the fourth resistor R4 from affecting the amplitude-frequency characteristics of the high-pass filter composed of the filter capacitor CO and the filter resistor R0.

[0064] It can be understood that the output signal Vout of the first comparator COMP can be used as an enable signal for opening or closing the third switch S3, or the output signal Vout of the first comparator COMP can also be used as a start signal for subsequent circuits, for example, see Fig.15 The output signal Vout of the first comparator COMP can be used as a start signal / signal establishment completion indication signal of a subsequent signal processing circuit (eg, an analog-to-digital converter).

[0065] In order to better implement the filter circuit in the embodiment of the present application, on the basis of the filter circuit, the embodiment of the present application also provides a chip, which includes the above-mentioned filter circuit. The chip (Integrated Circuit, IC) is also called a chip, and the chip can be but is not limited to a SOC (System on Chip, chip-level system) chip or a SIP (system in package, system-level packaging) chip. Since the chip has the filter circuit in the above-mentioned embodiment, it has all the beneficial effects of the filter circuit, which will not be repeated here.

[0066] The embodiment of the present application also provides an electronic device, which includes a device body and a chip as described above provided in the device body. The electronic device may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a car central control screen, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include, but are not limited to, smart watches, smart bracelets, and cervical massagers. Mobile terminals include, but are not limited to, smart phones, laptops, tablet computers, and POS (point of sales terminal). Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0067] The above are only preferred embodiments of the present application, and are not intended to limit the present application in any form. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A filter circuit, characterized in that: include: A filter module, the filter module comprising a filter capacitor and a filter resistor, the first end of the filter capacitor is connected to the input signal, the second end of the filter capacitor is connected to the first end of the filter resistor, the second end of the filter resistor is connected to the ground end, and the second end of the filter capacitor outputs the filtered output signal; A common-mode bias module for outputting a common-mode voltage, wherein an output end of the common-mode bias module is connected to the filter module to bias an output signal outputted from the second end of the filter capacitor at the common-mode voltage; A driving module for outputting a starting current, wherein an output end of the driving module is connected to the filtering module; In the process that the voltage at the second end of the filter capacitor rises to the common mode voltage, the driving module inputs the starting current to the second end of the filter capacitor, so that the voltage at the second end of the filter capacitor quickly rises to the common mode voltage.

2. The filter circuit according to claim 1, characterized in that: The input end of the driving module is connected to the common mode bias module to access the common mode voltage; The output end of the driving module is connected to the second end of the filter capacitor so that the second end of the filter capacitor quickly rises to the common mode voltage.

3. The filter circuit according to claim 2, characterized in that: The driving module includes a first operational amplifier; The non-inverting input terminal of the first operational amplifier is connected to the common-mode bias module to access the common-mode voltage; The inverting input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected to the second terminal of the filter capacitor.

4. The filter circuit according to claim 3, characterized in that: The driving module further includes a first switch; The first end of the first switch is connected to the second end of the filter capacitor, the second end of the first switch is connected to the output end of the first operational amplifier, and the output end of the first operational amplifier is connected to the second end of the filter resistor; Wherein, before the second end of the filter capacitor rises to the common mode voltage, the first switch is in a closed state; after the second end of the filter capacitor rises to the common mode voltage, the first switch is in an open state.

5. The filter circuit according to claim 3, characterized in that: The driving module further includes a second switch; The first end of the second switch is connected to the second end of the filter capacitor, and the second end of the second switch is connected to the first end of the filter resistor; Before the second end of the filter capacitor rises to the common mode voltage, the second switch is in an open state; after the second end of the filter capacitor rises to the common mode voltage, the second switch is in a closed state, and the first operational amplifier is enabled and turned off.

6. The filter circuit according to claim 4 or 5, characterized in that: The common mode bias module includes a first resistor and a second resistor; The first end of the first resistor is connected to the power supply end, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the ground end; A second node between the first resistor and the second resistor outputs the common mode voltage.

7. The filter circuit according to claim 5, characterized in that: The common mode bias module includes a third resistor; The first end of the third resistor is connected to the power supply end, the second end of the third resistor is connected to the first end of the filter resistor, and the second end of the second switch is connected to a third node between the third resistor and the filter resistor.

8. The filter circuit according to claim 2, characterized in that: The filtering circuit also includes a detection module; The input end of the detection module is connected to the second end of the filter capacitor to detect whether the voltage of the second end of the filter capacitor reaches the common mode voltage, and the output end of the detection module is connected to the driving module to control whether the driving module continues to output the starting current.

9. The filter circuit according to claim 8, characterized in that: The detection module includes a first comparator; The first input terminal of the first comparator is connected to the second terminal of the filter capacitor, and the second input terminal of the first comparator is connected to the common mode bias module; The output end of the first comparator is connected to the driving module to control the driving module to stop outputting the starting current after the second end of the filter capacitor reaches the common mode voltage.

10. The filter circuit according to claim 9, characterized in that: The detection module also includes a first capacitor and a fourth resistor; The first end of the fourth resistor is connected to the second end of the filter capacitor, the second end of the fourth resistor is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the ground terminal; The first input terminal of the first comparator is connected to a fourth node between the first capacitor and the fourth resistor.

11. A chip, characterized in that: The filter circuit comprises the filter circuit as claimed in any one of claims 1 to 10.

12. An electronic device, characterized in that: Comprising the chip as claimed in claim 11.

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