RC low-pass filter and fast filter establishment method

Abstract

This invention provides an RC low-pass filter and a fast filter setup method. The RC low-pass filter includes at least one first-order RC low-pass filter and at least one charge transfer unit, wherein the at least one first-order RC low-pass filter and the at least one charge transfer unit are connected in series. The at least one charge transfer unit realizes charge transfer of the at least one first-order RC low-pass filter through multiple capacitors, multiple switches, and multiple energy transfer modules to obtain a preset low bandwidth and a preset RC low-pass filter setup time. The fast filter setup method is used to quickly set up the aforementioned RC low-pass filter. This invention achieves rapid setup of an RC low-pass filter with low bandwidth and short setup time by setting a charge transfer unit in the RC low-pass filter.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and in particular to an RC low-pass filter and a method for rapid filter setup. Background Technology

[0002] In traditional RC low-pass filter construction scenarios, there is a fixed relationship between its settling time and bandwidth. In certain specific applications, such as adjustable voltage sources, it is necessary to obtain the lowest possible bandwidth of the RC low-pass filter to achieve the ideal low-pass filtering effect, but at the same time, it is also desirable to quickly reach the new output voltage when the output voltage is changed.

[0003] For traditional RC low-pass filters, since settling time and bandwidth are calculated using known formulas, it's difficult to simultaneously achieve fast settling and low bandwidth. Existing solutions add external operational amplifiers to the traditional RC low-pass filter to directly charge and discharge the filter's capacitors, thereby reducing settling time. While this method reduces settling time to some extent, it also has drawbacks. The settling time of such RC low-pass filters is still limited by the driving capability of the external operational amplifier and the size of the RC low-pass filter's capacitors.

[0004] Therefore, how to quickly build an RC low-pass filter without relying on the driving capability of the operational amplifier circuit and the capacity limitations of the RC low-pass filter itself has become an urgent problem to be solved. Summary of the Invention

[0005] This invention provides an RC low-pass filter and a method for fast filter establishment, which solves the defects in the prior art where the fast establishment of an RC low-pass filter is limited by the driving capability of the external operational amplifier circuit and the capacity of the RC low-pass filter itself.

[0006] In a first aspect, the present invention provides an RC low-pass filter, comprising:

[0007] The at least one first-order RC low-pass filter and the at least one charge transfer unit are connected in series.

[0008] The at least one charge transfer unit realizes the charge transfer of the at least first-order RC low-pass filter through multiple capacitors, multiple switches and multiple energy transfer modules, so as to obtain a preset low bandwidth and a preset RC low-pass filter settling time.

[0009] According to the RC low-pass filter proposed in this invention, each charge transfer unit includes capacitors C1 and C2, switches S1, S2, S3, and S4, energy transfer module ET1, and energy transfer module ET2, wherein:

[0010] The first terminal of the energy transfer module ET1 is connected to the first terminal of the switch S1, and the second terminal of the switch S1 is connected to the first terminal of the capacitor C1.

[0011] The first terminal of capacitor C1 is connected to the first terminal of switch S2, and the second terminal of switch S2 is connected to the first terminal of switch S3 in sequence.

[0012] The second end of the switch S3 is connected to the first end of the switch S4 and the first end of the capacitor C2, respectively. The second end of the switch S4 is connected to the first end of the energy transfer module ET2.

[0013] According to the RC low-pass filter proposed in this invention, a bias voltage VBP is set on the second terminal of the energy transfer module ET1 and the second terminal of the capacitor C1.

[0014] The second terminal of the energy transfer module ET2 and the second terminal of the capacitor C2 are both provided with a bias voltage VBN.

[0015] According to the RC low-pass filter proposed in this invention, the energy transfer module ET1 is used to transfer the stored energy of the capacitor C1 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S1 is closed;

[0016] Correspondingly, the energy transfer module ET2 is used to transfer the stored energy of the capacitor C2 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S4 is closed.

[0017] According to the RC low-pass filter proposed in this invention, the capacitances of capacitor C1 and capacitor C2 are the same or different between the at least one charge transfer unit;

[0018] The capacitances of capacitor C1 and capacitor C2 in each charge transfer unit may be the same or different.

[0019] According to the RC low-pass filter proposed in this invention, each RC low-order filter includes a resistor R0 and a capacitor C0. The first end of the resistor R0 is connected to the input signal, the second end of the resistor R0 is connected to the first end of the capacitor C0, and the second end of the capacitor C0 is grounded.

[0020] According to the RC low-pass filter proposed in this invention, the maximum value of the input signal is less than the bias voltage VBP, and the minimum value of the input signal is greater than the bias voltage VBN.

[0021] The RC low-pass filter proposed according to the present invention further includes an auxiliary amplifier and an auxiliary amplifier control switch, wherein the auxiliary amplifier is used to adjust the voltage of the capacitor C0 by outputting a preset micro current;

[0022] The first terminal of the auxiliary amplifier is connected to the first terminal of the resistor R0, the second terminal of the auxiliary amplifier is connected to the first terminal of the auxiliary amplifier control switch, and the second terminal of the auxiliary amplifier control switch is connected to the second terminal of the resistor R0 and the first terminal of the capacitor C0.

[0023] According to the RC low-pass filter proposed in this invention, the at least first-order RC low-pass filter includes a first-order RC low-pass filter and an arbitrary higher-order RC low-pass filter.

[0024] Secondly, the present invention also provides a method for fast establishment of an RC low-pass filter, comprising:

[0025] Disconnect all switches S1, S2, S3, and S4 in all charge transfer units, and set the voltage across all capacitors C1 and C2 to 0.

[0026] Determine the capacitances of capacitors C1 and C2 in all charge transfer units. Based on the voltage change of the input signal, the bias voltage VBP, and the bias voltage VBN, calculate the charge transfer units that need to participate in charge transfer. Close switch S2 or switch S3 in the corresponding charge transfer unit to transfer charge from capacitor C0 in at least the first-order RC low-pass filter to capacitor C1 or capacitor C2 in the corresponding charge transfer unit. After the charge transfer is completed, open switch S2 or switch S3 and close the auxiliary amplifier control switch to fine-tune the voltage on capacitor C0 based on a preset micro-drive current. After a preset fine-tuning time, open the auxiliary amplifier control switch.

[0027] Close the switch S1 or switch S4 in the corresponding charge transfer unit to transfer the charge energy in the capacitor C1 or capacitor C2. After the voltage across the capacitor C1 or capacitor C2 returns to 0, open the switch S1 or switch S4 to return the system to its initial state.

[0028] The RC low-pass filter and the fast filter setup method provided by this invention achieve the rapid setup of an RC low-pass filter with low bandwidth and short setup time by setting a charge transfer unit in the RC low-pass filter. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is an overall structural diagram of the RC low-pass filter provided by the present invention;

[0031] Figure 2 This is a detailed structural diagram of the RC low-pass filter provided by the present invention;

[0032] Figure 3 This is a flowchart illustrating the fast establishment method for the RC low-pass filter provided by the present invention.

[0033] Figure 4 This is a detailed structural diagram of an example of the RC low-pass filter provided by the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] Figure 1 This is an overall structural diagram of the RC low-pass filter provided by the present invention, as shown below. Figure 1 As shown, it includes:

[0036] The at least one first-order RC low-pass filter and the at least one charge transfer unit are connected in series.

[0037] The at least one charge transfer unit realizes the charge transfer of the at least first-order RC low-pass filter through multiple capacitors, multiple switches and multiple energy transfer modules, so as to obtain a preset low bandwidth and a preset RC low-pass filter settling time.

[0038] The RC low-pass filter proposed in this invention comprises at least one first-order RC low-pass filter and at least one charge transfer unit, i.e., it is composed of multiple first-order RC low-pass filters and multiple charge transfer units connected in series, as shown in the overall structure. Figure 1 As shown, it consists of multiple first-order RC low-pass filters and multiple charge transfer units.

[0039] An RC low-pass filter is constructed by connecting a resistor R and a capacitor C in series, with the capacitor C connected in parallel with the load. It is then connected in series with several charge transfer units. The number of charge transfer units needs to be calculated based on the actual electrical energy to be transferred. Each charge transfer unit includes multiple capacitors, multiple switches, and multiple energy transfer modules, which can quickly transfer the charge of the RC low-pass filter, thereby achieving the required low-pass bandwidth in a short time.

[0040] This invention relates not only to first-order fast-establishment RC low-pass filters, but also to arbitrarily higher-order RC low-pass filters, and makes no limitations on this.

[0041] This invention enables the rapid establishment of an RC low-pass filter with low bandwidth and short setup time by incorporating a charge transfer unit into the RC low-pass filter.

[0042] Based on the above embodiments, each charge transfer unit includes capacitors C1 and C2, switches S1, S2, S3, and S4, energy transfer module ET1, and energy transfer module ET2, wherein:

[0043] The first terminal of the energy transfer module ET1 is connected to the first terminal of the switch S1, and the second terminal of the switch S1 is connected to the first terminal of the capacitor C1.

[0044] The first terminal of capacitor C1 is connected to the first terminal of switch S2, and the second terminal of switch S2 is connected to the first terminal of switch S3 in sequence.

[0045] The second end of the switch S3 is connected to the first end of the switch S4 and the first end of the capacitor C2, respectively. The second end of the switch S4 is connected to the first end of the energy transfer module ET2.

[0046] Specifically, such as Figure 2 As shown, each dashed box contains a single charge transfer unit, which are numbered CTE1 to CTEn sequentially.

[0047] Each charge transfer unit includes: capacitors C1 and C2; switches S1, S2, S3, and S4; and energy transfer modules ET1 and ET2. Figure 2 In this context, ET1_n represents the ET1 module of the nth charge transfer unit, and the numbering of other modules is similar.

[0048] It can be seen that in each charge transfer unit, the circuit structure with the connection point of switches S2 and S3 as the symmetrical point is such that on one side, the energy transfer module ET1 and switch S1 are connected in series, then in parallel with capacitor C1 and then connected to switch S2; on the other side, the energy transfer module ET2 and switch S2 are connected in series, then in parallel with capacitor C2 and then connected to switch S3.

[0049] The second terminal of the energy transfer module ET1 and the second terminal of the capacitor C1 are both provided with a bias voltage VBP.

[0050] The second terminal of the energy transfer module ET2 and the second terminal of the capacitor C2 are both provided with a bias voltage VBN.

[0051] In each charge transfer unit, the two ends of the circuit are connected to a bias voltage. One end of the energy transfer module ET1 and one end of the capacitor C1 are connected to the external bias voltage VBP (Bias Voltage Positive). Correspondingly, one end of the energy transfer module ET2 and one end of the capacitor C2 are connected to the external bias voltage VBN (Bias Voltage Negative).

[0052] Based on the above embodiments, the energy transfer module ET1 is used to transfer the stored energy of the capacitor C1 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S1 is closed;

[0053] Correspondingly, the energy transfer module ET2 is used to transfer the stored energy of the capacitor C2 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S4 is closed.

[0054] Specifically, in each charge transfer unit, the core function is provided by the energy transfer modules ET1 and ET2. When switches S1 and S4 are closed, the energy stored in capacitors C1 and C2 is transferred to other components. The energy transfer modules can transfer the energy stored in capacitors C1 and C2 to the external environment in the form of heat, or they can transfer the energy stored in capacitors C1 and C2 to the bias voltage VBP and / or bias voltage VBN in the form of electrical energy.

[0055] Typically, the energy transfer module is a resistor that transfers the energy on the capacitor to the external environment as heat, which is simple and reliable to implement. Alternatively, it can be a flyback switching power supply or other circuits that transfer the energy on the capacitor back to the bias voltage VBP and / or bias voltage VBN as electrical energy, thereby reducing the power consumption of the filter.

[0056] This invention, by setting up a charge transfer unit, and through the flexible configuration of switches, capacitors and energy transfer modules within the charge transfer unit, enables on-demand adjustment of low-pass bandwidth and setup time, and features simple, fast and flexible implementation.

[0057] Based on the above embodiments, the capacitances of capacitor C1 and capacitor C2 are the same or different between the at least one charge transfer unit;

[0058] The capacitances of capacitor C1 and capacitor C2 in each charge transfer unit may be the same or different.

[0059] Specifically, such as Figure 2 As shown, multiple charge transfer units all contain the same circuit structure, with capacitors C1 and C2. The corresponding capacitance values ​​can be set to be the same or different for different charge transfer units. Alternatively, within the same charge transfer unit, capacitors C1 and C2 can be set to the same capacitance or different capacitances. All of the above settings can be flexibly configured and adjusted according to actual needs.

[0060] Based on the above embodiments, each RC low-order filter includes a resistor R0 and a capacitor C0. The first end of the resistor R0 is connected to the input signal, the second end of the resistor R0 is connected to the first end of the capacitor C0, and the second end of the capacitor C0 is grounded.

[0061] exist Figure 2 In the process, an RC low-pass filter is connected in series before multiple charge transfer units. Each RC low-order filter includes a resistor R0 and a capacitor C0. R0 and C0 are traditional RC low-pass filters. One end of the resistor R0 is connected to the input signal, and the other end is connected to the capacitor C0. Then, the other end of C0 is grounded. It can be seen that the load connected in parallel with the capacitor C0 is the multiple charge transfer units.

[0062] Relative to the input signal connected by resistor R0, the present invention sets the bias voltage in the charge transfer unit as follows:

[0063] The voltage of VBP needs to be higher than the maximum value of the input signal, and the voltage of VBN needs to be lower than the minimum value of the input signal.

[0064] Optionally, the present invention provides an auxiliary amplifier and an auxiliary amplifier control switch connected in parallel on both sides of the RC low-pass filter. The auxiliary amplifier is used to adjust the voltage of the capacitor C0 by outputting a preset micro current.

[0065] The first terminal of the auxiliary amplifier is connected to the first terminal of the resistor R0, the second terminal of the auxiliary amplifier is connected to the first terminal of the auxiliary amplifier control switch, and the second terminal of the auxiliary amplifier control switch is connected to the second terminal of the resistor R0 and the first terminal of the capacitor C0.

[0066] It should be noted that in actual circuits, switches are not ideal devices, and clock feedthrough and charge injection exist. After charge transfer, the filter output will still have a slight error. If the resistance of resistor R0 is very large, the filter will need a long time to eliminate the error. Therefore, an auxiliary amplifier and a corresponding auxiliary amplifier control switch are added in parallel across resistor R0. After reset, the auxiliary amplifier inputs or outputs a small current to fine-tune the voltage across capacitor C0 to further eliminate the error.

[0067] By closing the auxiliary amplifier control switch, the auxiliary amplifier fine-tunes the voltage on capacitor C0 with a small drive current. After a period of time, the auxiliary amplifier control switch is opened, allowing the system to return to its initial state.

[0068] Although similar circuit structures to auxiliary amplifiers and auxiliary amplifier control switches exist in the prior art, they are fundamentally different from the auxiliary amplifier proposed in this invention:

[0069] (1) The present invention introduces a charge transfer unit to reduce the filter settling time. The auxiliary amplifier is introduced to compensate for various errors, such as voltage errors caused by factors like charge injection from the switch and limited resolution due to the limited number of charge transfer units. The required driving capability of the auxiliary amplifier does not need to be very strong. If the devices used are sufficiently idealized and there are enough charge transfer units, it is not necessary to set up the auxiliary amplifier and the auxiliary amplifier control switch. In the prior art, similar circuit structures are used to reduce settling time, which requires a very strong driving capability and cannot be removed. That is, for the prior art, this circuit is mandatory, while in this application it is optional.

[0070] (2) If the device used has no parasitic parameters and the charge transfer time is 0, then the settling time of the RC low-pass filter in this invention can be very short. In the prior art, the charging and discharging time is related to the driving capability of the external circuit and cannot be set to zero;

[0071] (3) If the device used has no parasitic parameters, the settling time of the RC low-pass filter in this application is independent of the capacitance C0 of the RC low-pass filter. The capacitance C0 of the RC low-pass filter can be increased without limit to design an RC low-pass filter with extremely low bandwidth but still very short settling time. In the prior art, the limited driving capability of the external circuit makes it impossible for the capacitance of the RC low-pass filter to increase without limit. Usually, a trade-off needs to be made between settling time and bandwidth.

[0072] This invention achieves fine-tuning and correction of errors generated during the charge transfer stage by selectively setting auxiliary amplifiers, thus ensuring the accuracy of the output.

[0073] Figure 3 This is a flowchart illustrating the fast establishment method for the RC low-pass filter provided by the present invention, as shown below. Figure 3 As shown, it includes:

[0074] Step S1: Disconnect all switches S1, S2, S3 and S4 in all charge transfer units, so that the voltage across all capacitors C1 and C2 is set to 0.

[0075] Step S2: Determine the capacitance of capacitor C1 and capacitor C2 in all charge transfer units. Based on the voltage change of the input signal, bias voltage VBP, and bias voltage VBN, calculate the charge transfer units that need to participate in charge transfer. Close switch S2 or switch S3 in the corresponding charge transfer unit to transfer charge from capacitor C0 in at least the first-order RC low-pass filter to capacitor C1 or capacitor C2 in the corresponding charge transfer unit. After the charge transfer is completed, open switch S2 or switch S3 and close the auxiliary amplifier control switch to fine-tune the voltage on capacitor C0 based on a preset micro-drive current. After a preset fine-tuning time, open the auxiliary amplifier control switch.

[0076] Step S3: Close switch S1 or switch S4 in the corresponding charge transfer unit to transfer the charge energy in capacitor C1 or capacitor C2. After the voltage across capacitor C1 or capacitor C2 returns to 0, open switch S1 or switch S4 to return the system to its initial state.

[0077] Specifically, the process of quickly establishing a low-pass RC filter proposed in this invention includes the following three states:

[0078] (1) Initial state

[0079] If all switches S1 to S4 in all charge transfer units are turned off, the voltage across capacitors C1 and C2 in all charge transfer units will be 0.

[0080] (2) Charge transfer state

[0081] At this point, based on the change in the input signal voltage, the bias voltage VBP and the bias voltage VBN, and the capacitance between the capacitors in the filter, the charge transfer unit that needs to participate in the charge transfer is calculated.

[0082] Furthermore, close the switch S2 or switch S3 in the corresponding charge transfer unit so that the capacitor C0 of the RC low-pass filter transfers charge with the capacitor C1 or capacitor C2 in the corresponding charge transfer unit. After the charge transfer is completed, open the switch S2 or switch S3 in the corresponding charge transfer unit.

[0083] (3) Reset state

[0084] Then close the switch S1 or switch S4 in the corresponding charge transfer unit, so that the energy transferred to capacitor C1 or capacitor C2 in the charge transfer state is transferred out. After the voltage across capacitor C1 or capacitor C2 returns to 0, open switch S1 or switch S4, and the system returns to the initial state.

[0085] This invention achieves rapid charge transfer by setting up a charge transfer unit and opening and closing multiple switches in the charge transfer unit, thus reaching the final output value in a short time.

[0086] (4) Error elimination status

[0087] Optionally, since the switch is not an ideal device, clock feedthrough and charge injection exist. This invention connects an auxiliary amplifier and an auxiliary amplifier control switch in parallel across the RC low-pass filter. The auxiliary amplifier adjusts the voltage of capacitor C0 by outputting a preset micro-current. By closing the auxiliary amplifier control switch, the auxiliary amplifier fine-tunes the voltage on capacitor C0 with a small drive current. After a period of time, the auxiliary amplifier control switch is opened, allowing the system to return to its initial state.

[0088] The following example of a practical circuit application illustrates the implementation principle of this invention. Figure 4 As shown, it contains three charge transfer units CTE1 to CTE3. In order to counteract non-ideal factors such as charge injection from the switch, an auxiliary amplifier A1 and a switch SA1 are added.

[0089] Assume VBP = 2V A (V A (If positive), VBN = -2V AThe capacitance of capacitor C0 is C; the capacitances of C1_1 and C2_1 are 2C; the capacitances of C1_2 and C2_2 are C; the capacitances of C1_3 and C2_3 are C / 2; the voltage across the capacitors in each charge transfer unit is 0; all switches in this circuit are in the open state, and the initial input is V. IN1 =-V A The voltage across C0 is V. IN1 =-V A .

[0090] (1) Initial state

[0091] All switches in this circuit are in the off state, and the input is -V. A The voltage across capacitor C0 is also -V. A At this point, the filter operates in the same manner as a traditional RC low-pass filter.

[0092] (2) Charge transfer state

[0093] After a period of time, the input changes to V. IN2 = +0.8V A At this point, it enters a charged state;

[0094] Capacitor C0 is for V IN1 Jump to V IN2 The amount of charge that needs to be transferred during the charge transfer process is:

[0095] ΔQ C0 =C*ΔU C0 =C*(V IN2 -V IN1 ) = 1.8V A *C (1)

[0096] In the aforementioned charge transfer unit, the total capacitance C required to participate in charge transfer is... T The following relationship must be satisfied:

[0097] ΔQ CT =C T *ΔU CT =C T *(V BP -V IN2 ) = 1.2V A *C T (2)

[0098] ΔQ CT =ΔQ C0 (3)

[0099] Combining equations (1) to (3) above, we can solve for C. T= 1.5*C, meaning the total capacitance involved in charge transfer across all charge transfer units is 1.5*C. Because ΔU CT Since the number is positive, the capacitors involved in charge transfer are C1_2 and C1_3 in CTE2 and CTE3, and the switches that need to be turned on are the corresponding S2_2 and S2_3.

[0100] Then close switches S2_2 and S2_3. After the charge transfer is complete, open switches S2_2 and S2_3.

[0101] (3) Reset state

[0102] After the charge transfer state, the voltage across capacitors C1_2 and C1_3 is not zero, and the energy on these two capacitors needs to be transferred out before the next charge transfer.

[0103] Close switches S2_2 and S2_3, causing energy transfer modules ET1_2 and ET1_3 to transfer energy from C1_2 and C1_3. Once the voltage on C1_2 and C1_3 is 0, open switches S1_2 and S1_3, and the system returns to its initial state.

[0104] The above is one example of rapid setup of an RC low-pass filter. In practical applications, the device components can be flexibly configured according to requirements to meet various low-bandwidth and short-time setup needs.

[0105] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0106] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, 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 can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An RC low-pass filter, characterized in that, include: The at least one first-order RC low-pass filter and the at least one charge transfer unit are connected in series. The at least one charge transfer unit realizes the charge transfer of the at least first-order RC low-pass filter through multiple capacitors, multiple switches and multiple energy transfer modules to obtain a preset low bandwidth and a preset RC low-pass filter settling time. Each charge transfer unit includes capacitors C1 and C2, switches S1, S2, S3, and S4, and energy transfer modules ET1 and ET2, wherein: The first terminal of the energy transfer module ET1 is connected to the first terminal of the switch S1, and the second terminal of the switch S1 is connected to the first terminal of the capacitor C1. The first terminal of capacitor C1 is connected to the first terminal of switch S2, and the second terminal of switch S2 is connected to the first terminal of switch S3 in sequence. The second end of the switch S3 is connected to the first end of the switch S4 and the first end of the capacitor C2, respectively. The second end of the switch S4 is connected to the first end of the energy transfer module ET2.

2. The RC low-pass filter according to claim 1, characterized in that, The second terminal of the energy transfer module ET1 and the second terminal of the capacitor C1 are both provided with a bias voltage VBP. The second terminal of the energy transfer module ET2 and the second terminal of the capacitor C2 are both provided with a bias voltage VBN.

3. The RC low-pass filter according to claim 2, characterized in that, The energy transfer module ET1 is used to transfer the stored energy of the capacitor C1 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S1 is closed. Correspondingly, the energy transfer module ET2 is used to transfer the stored energy of the capacitor C2 to the external environment of the circuit in the form of thermal energy, or to the bias voltage VBP and / or the bias voltage VBN in the form of electrical energy when the switch S4 is closed.

4. The RC low-pass filter according to claim 1, characterized in that, Between the at least one charge transfer unit, the capacitances of capacitor C1 and capacitor C2 may be the same or different; The capacitances of capacitor C1 and capacitor C2 in each charge transfer unit may be the same or different.

5. The RC low-pass filter according to claim 1, characterized in that, Each RC low-order filter includes a resistor R0 and a capacitor C0. The first end of the resistor R0 is connected to the input signal, the second end of the resistor R0 is connected to the first end of the capacitor C0, and the second end of the capacitor C0 is grounded.

6. The RC low-pass filter according to claim 5, characterized in that, The maximum value of the input signal is less than the bias voltage VBP, and the minimum value of the input signal is greater than the bias voltage VBN.

7. The RC low-pass filter according to claim 5, characterized in that, It also includes an auxiliary amplifier and an auxiliary amplifier control switch, wherein the auxiliary amplifier is used to adjust the voltage of the capacitor C0 by outputting a preset micro current; The first terminal of the auxiliary amplifier is connected to the first terminal of the resistor R0, the second terminal of the auxiliary amplifier is connected to the first terminal of the auxiliary amplifier control switch, and the second terminal of the auxiliary amplifier control switch is connected to the second terminal of the resistor R0 and the first terminal of the capacitor C0.

8. The RC low-pass filter according to claim 1, characterized in that, The at least one-order RC low-pass filter includes a first-order RC low-pass filter and any higher-order RC low-pass filter.

9. A method for rapidly establishing an RC low-pass filter, based on the RC low-pass filter according to any one of claims 1 to 8, characterized in that, include: Disconnect all switches S1, S2, S3, and S4 in all charge transfer units, and set the voltage across all capacitors C1 and C2 to 0. Determine the capacitances of capacitor C1 and capacitor C2 in all charge transfer units. Based on the voltage change of the input signal, the bias voltage VBP, and the bias voltage VBN, calculate the charge transfer units that need to participate in charge transfer. Close switch S2 or switch S3 in the corresponding charge transfer unit to transfer charge from capacitor C0 in at least the first-order RC low-pass filter to capacitor C1 or capacitor C2 in the corresponding charge transfer unit. After the charge transfer is completed, open switch S2 or switch S3 and close the auxiliary amplifier control switch to fine-tune the voltage on capacitor C0 based on a preset micro-drive current. After a preset fine-tuning time, open the auxiliary amplifier control switch. Close the switch S1 or switch S4 in the corresponding charge transfer unit to transfer the charge energy in the capacitor C1 or capacitor C2. After the voltage across the capacitor C1 or capacitor C2 returns to 0, open the switch S1 or switch S4 to return the system to its initial state.

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