An amplifier kickback prevention circuit and method

Abstract

The application relates to the technical field of integrated circuit design, and particularly discloses an amplifier anti-kick circuit and method, which comprises: an anti-kick OR gate, an input end of which is electrically connected with a chopping phase signal of an amplifier; and a pair of anti-kick capacitors, one side of each of the anti-kick capacitors is electrically connected with an output end of the anti-kick OR gate, the other side of each of the anti-kick capacitors is electrically connected with one side of a feedback capacitor in a pair of feedback capacitors of the amplifier, and one side of the feedback capacitor is a plate electrically connected with a feedback chopping switch of the amplifier. The anti-kick circuit can keep the common-mode voltage of the capacitor amplifier almost unchanged at different phases, obviously improves the kick of the input signal, and greatly improves the quality of the sampling signal.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit design technology, and specifically to an amplifier anti-kickback circuit and method. Background Technology

[0002] Linghui Lixin's patent applications CN114844479A (disclosing a capacitor-type programmable amplifier) ​​and CN119582773A (disclosing a low-noise programmable amplifier) ​​both disclose capacitor amplifiers with chopper switches, such as... Figure 1 As shown.

[0003] The capacitor amplifier with chopper switch described above can be simplified as follows: Figure 2 As shown. Each time the feedback chopper switch (SW_CHP) is turned off, due to the charge injection effect of the switch, the feedback capacitor C... FP and C FN The nodes Na and Nb on the right will introduce a voltage error due to the switching effect, which is reflected through the feedback capacitor C. FP and C FN Passed to amplifier G m1 Input V AIP and V AIN Then through C IP and C IN Passed to input V IP and V IN The input signal exhibits a kickback effect, which significantly impacts the quality of the sampled signal.

[0004] Based on this technical background, the present invention studies an amplifier anti-kickback circuit and method. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes an amplifier anti-kickback circuit and method. This anti-kickback circuit can ensure that the common-mode voltage of the capacitor amplifier remains almost constant in different phases, significantly improving the performance of the input signal in the event of a kickback, thereby greatly improving the quality of the sampled signal.

[0006] To achieve the above objectives, a first aspect of the present invention provides an amplifier anti-kickback circuit, comprising:

[0007] Anti-kickback gate, the input terminal is electrically connected to the chopper phase signal of the amplifier;

[0008] A pair of anti-kickback capacitors, each having one side plate electrically connected to the output terminal of the anti-kickback OR gate, and the other side plate electrically connected to one side plate of one of the pair of feedback capacitors in the amplifier, wherein one side plate of the feedback capacitor is electrically connected to a feedback chopper switch of the amplifier.

[0009] A second aspect of the present invention provides an amplifier anti-kickback method performed in the above-described anti-kickback circuit, comprising:

[0010] Connect the input terminal of the anti-kickback gate to the chopper phase signal of the amplifier.

[0011] One side plate of each of the pair of anti-kickback capacitors is electrically connected to the output terminal of the anti-kickback OR gate, and the other side plate is electrically connected to one side plate of one of the pair of feedback capacitors of the amplifier. At the same time, it is ensured that one side plate of the feedback capacitor is electrically connected to the differential feedback chopper switch of the amplifier.

[0012] The beneficial effects of this invention include:

[0013] The amplifier anti-kickback circuit proposed in this invention can make the common-mode voltage of the capacitor amplifier almost constant in different phases, which significantly improves the kickback of the input signal and thus greatly improves the quality of the sampled signal.

[0014] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0015] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0016] Figure 1 This is a schematic diagram of an existing capacitor amplifier with a chopper switch.

[0017] Figure 2 This is a simplified schematic diagram of an existing capacitor amplifier with a chopper switch.

[0018] Figure 3 This is a schematic diagram of a specific embodiment of the amplifier anti-kickback circuit proposed in this invention.

[0019] Figure 4 This is a schematic diagram showing the timing relationship between the in-phase chopper phase signal and the out-of-phase chopper phase signal in a specific embodiment of the amplifier anti-kickback circuit proposed in this invention.

[0020] Figure 5 This is a schematic diagram comparing simulation results of an amplifier with and without an anti-kickback circuit in a specific embodiment of the amplifier anti-kickback circuit proposed in this invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] CFP / C FN -Feedback capacitor, C KC - Anti-kickback capacitor, OR - Anti-kickback OR gate, Na / Nb - Node of the plate electrically connected to the feedback chopper switch of the amplifier, SW_CHP - Feedback chopper switch, PCH1 - In-phase chopper phase signal, PCH12 - Out-of-phase chopper phase signal. Detailed Implementation

[0023] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0024] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, while "inner" and "outer" refer to their position relative to the device's outline. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] This invention provides an amplifier anti-kickback circuit, such as... Figure 3 As shown, it includes:

[0026] The anti-kickback OR gate has its input terminal electrically connected to the chopped phase signal of the amplifier.

[0027] A pair of anti-kickback capacitors C KC Each anti-kickback capacitor C KC One side plate is electrically connected to the output terminal of the anti-kickback or gate OR, and the other side plate is connected to a pair of feedback capacitors C of the amplifier. FP / C FN One of the feedback capacitors C FP / C FN One side plate is electrically connected, and the feedback capacitor C FP / C FN One of the plates is electrically connected to a feedback chopper switch SW_CHP of the amplifier.

[0028] The amplifier kickback prevention circuit of the present invention can make the common-mode voltage of the capacitor amplifier remain almost constant in different phases, which significantly improves the kickback of the input signal and thus greatly improves the quality of the sampled signal.

[0029] According to the present invention, the anti-kick OR gate is a single OR gate or a pair of OR gates, and each of the single OR gate and the pair of OR gates is a two-input OR gate;

[0030] The chopper phase signal includes the in-phase chopper phase signal PCH1 and the out-of-phase chopper phase signal PCH12.

[0031] According to the present invention, when the anti-kickback OR gate is a single OR gate, the input terminals of the single OR gate are electrically connected to the in-phase chopped phase signal PCH1 and the out-of-phase chopped phase signal PCH12, respectively, and the output terminal is simultaneously connected to a pair of anti-kickback capacitors C. KC One side of the electrode plate is electrically connected;

[0032] A pair of anti-kickback capacitors C KC The other plate is connected to a pair of feedback capacitors C. FP / C FN One side of the electrode plate is electrically connected.

[0033] According to the present invention, when the anti-kickback OR gate is a pair of OR gates, the input terminal of each OR gate is electrically connected to the in-phase chopped phase signal PCH1 and the out-of-phase chopped phase signal PCH12, respectively, and the output terminal is connected to an anti-kickback capacitor C. KC One side plate is electrically connected, and the anti-kickback capacitor C KC The other plate is connected to a feedback capacitor C FP / C FN One side of the electrode plate is electrically connected.

[0034] According to the present invention, each anti-kickback capacitor C KC The capacitance value is less than that of a feedback capacitor C. FP / C FN The capacitance value.

[0035] The present invention also provides an amplifier anti-kickback method in the above-described anti-kickback circuit, comprising:

[0036] Connect the input of the anti-kickback or gate OR to the chopper phase signal of the amplifier.

[0037] A pair of anti-kickback capacitors C KC Each anti-kickback capacitor C KC One side plate is electrically connected to the output terminal of the anti-kick-back or gate OR, and the other side plate is connected to a pair of feedback capacitors C of the amplifier. FP / C FN One of the feedback capacitors C FP / C FN One side plate is electrically connected, while ensuring that the feedback capacitor C FP / C FN One of the plates is electrically connected to the differential feedback chopper switch SW_CHP of the amplifier.

[0038] According to the present invention, it further includes:

[0039] Set the anti-kick OR gate to a single OR gate or a pair of OR gates, and set each of the single OR gate and the pair of OR gates to a two-input OR gate;

[0040] The chopper phase signal includes the in-phase chopper phase signal PCH1 and the out-of-phase chopper phase signal PCH12.

[0041] According to the present invention, when the anti-kickback OR gate is a single OR gate, the input terminal of the single OR gate is electrically connected to the in-phase chopped phase signal PCH1 and the out-of-phase chopped phase signal PCH12 respectively, and the output terminal is simultaneously connected to a pair of anti-kickback capacitors C. KC One side of the electrode plate is electrically connected;

[0042] A pair of anti-kickback capacitors C KC The other plate is connected to a pair of feedback capacitors C. FP / C FN One side of the electrode plate is electrically connected.

[0043] According to the present invention, when the anti-kickback OR gate is a pair of OR gates, the input terminal of each OR gate is electrically connected to the in-phase chopped phase signal PCH1 and the out-of-phase chopped phase signal PCH12 respectively, and the output terminal is connected to an anti-kickback capacitor C. KC One side plate is electrically connected, and the anti-kickback capacitor C is connected. KC The other plate is connected to a feedback capacitor C FP / C FN One side of the electrode plate is electrically connected.

[0044] According to the present invention, it further includes:

[0045] Each anti-kickback capacitor C KC The capacitance value is set to be less than one feedback capacitor C. FP / C FN The capacitance value.

[0046] The present invention will now be described in more detail through specific embodiments.

[0047] Example 1

[0048] like Figure 3 As shown, this embodiment provides an amplifier anti-kickback circuit, which is based on the existing structure of a capacitor amplifier with a chopper switch (such as...). Figure 1 , Figure 2 Based on the above, a small anti-back-kick capacitor C is added to nodes Na and Nb of the plate electrically connected to the feedback chopper switch of the amplifier. KCAligning with the switching phase of the feedback chopper switch SW_CHP, using the in-phase chopper phase signal PCH1 and the out-of-phase chopper phase signal PCH2, and an anti-kickback OR gate to drive the anti-kickback capacitor C. KC On the right side, the kickback effect of the feedback chopper switch SW_CHP is canceled; the anti-kickback circuit is implemented within the two dashed boxes; the two anti-kickback OR gate logics can also be combined into one anti-kickback OR gate.

[0049] Example timing diagrams for in-phase chopped phase signal PCH1 and out-of-phase chopped phase signal PCH2 are as follows: Figure 4 As shown.

[0050] In this embodiment, an amplifier with and without a kickback protection circuit are simulated, and the simulated voltage waveforms are compared, for example... Figure 5 As shown, the gain of the capacitor amplifier is set to 32 in the simulation;

[0051] Amplifier feedback capacitor C FP / C FN On the right side, when the feedback chopper switch SW_CHP is turned off, the right plate of the capacitor floats. Without the anti-back-kick circuit, the voltage jump of the right plate is about 115mV; after using the anti-back-kick circuit, the voltage jump is 5mW, which is greatly reduced.

[0052] Reaction to amplifier input V AIP and V AIN Without anti-kickback circuit, the amplifier input V AIP and V AIN There was a noticeable common-mode voltage jump; after using the anti-kickback circuit, the common-mode voltage remained almost constant in different phases, and the kickback was significantly improved.

[0053] The amplifier kickback prevention circuit proposed in the embodiments of the present invention can make the common-mode voltage of the capacitor amplifier remain almost constant in different phases, significantly improving the kickback of the input signal and thus greatly improving the quality of the sampled signal.

[0054] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An amplifier anti-kickback circuit, characterized in that, include: Anti-kickback gate, the input terminal is electrically connected to the chopper phase signal of the amplifier; A pair of anti-kickback capacitors, each with one side plate electrically connected to the output terminal of the anti-kickback OR gate, and the other side plate electrically connected to one side plate of one of the pair of feedback capacitors of the amplifier, wherein one side plate of the feedback capacitor is electrically connected to a feedback chopper switch of the amplifier. The anti-kickback OR gate is a single OR gate or a pair of OR gates, and each of the single OR gate and the pair of OR gates is a two-input OR gate; The chopping phase signal includes in-phase chopping phase signal and out-of-phase chopping phase signal; When the anti-kickback OR gate is a single OR gate, the input terminal of the single OR gate is electrically connected to the in-phase chopper phase signal and the out-of-phase chopper phase signal respectively, and the output terminal is simultaneously electrically connected to one plate of the pair of anti-kickback capacitors. The other side plate of the pair of anti-kickback capacitors is electrically connected to one side plate of the pair of feedback capacitors respectively. When the anti-kickback OR gate is a pair of OR gates, the input terminal of each OR gate is electrically connected to the in-phase chopper phase signal and the out-of-phase chopper phase signal respectively, the output terminal is electrically connected to one side plate of an anti-kickback capacitor, and the other side plate of the anti-kickback capacitor is electrically connected to one side plate of a feedback capacitor.

2. The anti-kickback circuit according to claim 1, characterized in that, The capacitance value of each anti-kickback capacitor is less than the capacitance value of a feedback capacitor.

3. An amplifier anti-kickback method performed in the anti-kickback circuit according to any one of claims 1-2, characterized in that, include: Connect the input terminal of the anti-kickback gate to the chopper phase signal of the amplifier. One side plate of each of the pair of anti-kickback capacitors is electrically connected to the output terminal of the anti-kickback OR gate, and the other side plate is electrically connected to one side plate of one of the pair of feedback capacitors of the amplifier, while ensuring that one side plate of the feedback capacitor is electrically connected to the differential feedback chopper switch of the amplifier. The anti-kickback OR gate is set as one OR gate or a pair of OR gates, and each of the one OR gate and the pair of OR gates is set as a two-input OR gate; The chopping phase signal includes in-phase chopping phase signal and out-of-phase chopping phase signal; When the anti-kickback OR gate is a single OR gate, the input terminal of the single OR gate is electrically connected to the in-phase chopper phase signal and the out-of-phase chopper phase signal respectively, and the output terminal is simultaneously electrically connected to one side plate of the pair of anti-kickback capacitors. The other side plate of the pair of anti-kickback capacitors is electrically connected to one side plate of the pair of feedback capacitors respectively. When the anti-kickback OR gate is a pair of OR gates, the input terminal of each OR gate is electrically connected to the in-phase chopper phase signal and the out-of-phase chopper phase signal respectively, the output terminal is electrically connected to one side plate of an anti-kickback capacitor, and the other side plate of the anti-kickback capacitor is electrically connected to one side plate of a feedback capacitor.

4. The method according to claim 3, characterized in that, Also includes: Set the capacitance value of each anti-kickback capacitor to be less than the capacitance value of one feedback capacitor.

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