CN-121710825-B - Anti-kickback circuit and method for amplifier
Abstract
The invention relates to the technical field of integrated circuit design, and particularly discloses an anti-kickback circuit and a method for an amplifier, wherein the anti-kickback circuit comprises an anti-kickback or gate, and an input end of the anti-kickback or gate is electrically connected with a chopping phase signal of the amplifier; the pair of anti-kickback capacitors, one side polar plate of each anti-kickback capacitor is electrically connected with the output end of the anti-kickback or gate, the other side polar plate is electrically connected with one side polar plate of one feedback capacitor in the pair of feedback capacitors of the amplifier, and one side polar plate of the feedback capacitor is a polar plate electrically connected with one feedback chopper switch of the amplifier. The anti-kickback circuit provided by the invention can keep the common-mode voltage of the capacitor amplifier almost unchanged in different phases, and can obviously improve the kickback of an input signal, thereby greatly providing the quality of a sampling signal.
Inventors
- WANG HANQING
- LIU YINCAI
Assignees
- 苏州领慧立芯科技有限公司
Dates
- Publication Date
- 20260512
- Application Date
- 20260213
Claims (4)
- 1. An amplifier anti-kickback circuit, comprising: the input end of the anti-kickback or gate is electrically connected with a chopping phase signal of the amplifier; One side polar plate of each anti-kickback capacitor is electrically connected with the output end of the anti-kickback or gate, the other side polar plate is electrically connected with one side polar plate of one feedback capacitor of a pair of feedback capacitors of the amplifier, and one side polar plate of the feedback capacitor is a polar plate electrically connected with one feedback chopper switch of the amplifier; The anti-kickback OR gate is an OR gate or a pair of OR gates, and each OR gate in the OR gate and the pair of OR gates is a two-input OR gate; the chopping phase signals comprise an in-phase chopping phase signal and an anti-phase chopping phase signal; When the anti-kickback or gate is an or gate, the input end of the or gate is respectively and electrically connected with the in-phase chopping phase signal and the anti-phase chopping phase signal, and the output end is simultaneously and electrically connected with one side polar plate of the pair of anti-kickback capacitors; The other side polar plates of the pair of anti-kickback capacitors are respectively and electrically connected with one side polar plates of the pair of feedback capacitors; When the anti-kickback or gate is a pair of or gates, the input end of each or gate is electrically connected with the in-phase chopping phase signal and the anti-phase chopping phase signal respectively, the output end of each or gate is electrically connected with one side polar plate of one anti-kickback capacitor, and the other side polar plate of the anti-kickback capacitor is electrically connected with one side polar plate of one feedback capacitor.
- 2. The kick-back prevention circuit of claim 1, wherein a capacitance value of each kick-back prevention capacitor is smaller than a capacitance value of one feedback capacitor.
- 3. A method of preventing kickback of an amplifier in a kickback prevention circuit as claimed in any one of claims 1-2, comprising: the input end of the anti-kickback OR gate is electrically connected with a chopping phase signal of the amplifier; One side polar plate of each anti-kickback capacitor in a pair of anti-kickback capacitors is electrically connected with the output end of the anti-kickback or gate, the other side polar plate is electrically connected with one side polar plate of one feedback capacitor in a pair of feedback capacitors of the amplifier, and meanwhile, one side polar plate of the feedback capacitor is ensured to be a polar plate electrically connected with a differential feedback chopper switch of the amplifier; setting the anti-kickback or gate as one or a pair of or gates, and setting each of the one or gate and the pair of or gates as two input or gates; the chopping phase signals comprise an in-phase chopping phase signal and an anti-phase chopping phase signal; When the anti-kickback or gate is an or gate, the input end of the or gate is respectively and electrically connected with the in-phase chopping phase signal and the anti-phase chopping phase signal, and the output end is simultaneously and electrically connected with one side polar plate of the pair of anti-kickback capacitors; The other side polar plates of the pair of anti-kickback capacitors are respectively and electrically connected with one side polar plates of the pair of feedback capacitors; when the anti-kickback or gate is a pair of or gates, the input end of each or gate is electrically connected with the in-phase chopping phase signal and the anti-phase chopping phase signal respectively, the output end of each or gate is electrically connected with one side polar plate of one anti-kickback capacitor, and the other side polar plate of the anti-kickback capacitor is electrically connected with one side polar plate of one feedback capacitor.
- 4. A method according to claim 3, further comprising: The capacitance value of each kick-back prevention capacitor is set to be smaller than the capacitance value of one feedback capacitor.
Description
Anti-kickback circuit and method for amplifier Technical Field The invention relates to the technical field of integrated circuit design, in particular to an amplifier anti-kickback circuit and a method. Background Both patent application CN114844479a (disclosing a capacitive programmable amplifier) and patent application CN119582773a (disclosing a low noise programmable amplifier) disclose capacitive amplifiers with chopper switches, as shown in fig. 1. The capacitive amplifier with chopper switch described above is simplified as shown in fig. 2. Each time the chopper switch (sw_chp) of the feedback is turned off, due to the charge injection effect of the switch, the nodes Na and Nb to the right of the feedback capacitors C FP and C FN introduce a voltage error due to the switch effect, and are transferred to the inputs V AIP and V AIN of the amplifier G m1 through the feedback capacitors C FP and C FN, and then to the inputs V IP and V IN through the feedback capacitors C IP and C IN. There is kick-back (kick-back) to the input signal, which in turn greatly affects the quality of the sampled signal. Based on the technical background, the invention researches an amplifier anti-kickback circuit and an amplifier anti-kickback method. Disclosure of Invention Aiming at the defects of the prior art, the invention provides an anti-kickback circuit and a method for an amplifier, and the slow anti-kickback circuit can keep the common mode voltage of a capacitor amplifier almost unchanged at different phases, so that the kickback of an input signal is obviously improved, and the quality of a sampling signal is greatly improved. In order to achieve the above object, a first aspect of the present invention provides an amplifier anti-kickback circuit, comprising: the input end of the anti-kickback or gate is electrically connected with a chopping phase signal of the amplifier; And one side polar plate of each anti-kickback capacitor is electrically connected with the output end of the anti-kickback or gate, the other side polar plate is electrically connected with one side polar plate of one feedback capacitor of the pair of feedback capacitors of the amplifier, and one side polar plate of the feedback capacitor is a polar plate electrically connected with one feedback chopper switch of the amplifier. A second aspect of the present invention provides a method for preventing an amplifier from kickback in the kickback prevention circuit, comprising The input end of the anti-kickback OR gate is electrically connected with a chopping phase signal of the amplifier; And electrically connecting one side polar plate of each anti-kickback capacitor of the pair of anti-kickback capacitors with the output end of the anti-kickback or gate, and electrically connecting the other side polar plate with one side polar plate of one feedback capacitor of the pair of feedback capacitors of the amplifier, and simultaneously ensuring that one side polar plate of the feedback capacitor is a polar plate electrically connected with a differential feedback chopper switch of the amplifier. The beneficial effects of the invention include: The anti-kickback circuit of the amplifier provided by the invention can keep the common-mode voltage of the capacitor amplifier almost unchanged in different phases, and can obviously improve the kickback of an input signal, thereby greatly providing the quality of a sampling signal. Additional features and advantages of the invention will be set forth in the detailed description which follows. Drawings The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the invention. Fig. 1 is a schematic diagram of a conventional capacitive amplifier with a chopper switch. Fig. 2 is a simplified schematic diagram of a conventional capacitive amplifier with chopper switch. Fig. 3 is a schematic structural diagram of an embodiment of an anti-kickback circuit of an amplifier according to the present invention. Fig. 4 is a schematic diagram of a timing relationship between an in-phase chopper phase signal and an anti-phase chopper phase signal in an embodiment of an anti-kick circuit of an amplifier according to the present invention. Fig. 5 is a schematic diagram showing simulation results of an amplifier with a kick-back prevention circuit and an amplifier without the kick-back prevention circuit according to an embodiment of the present invention. Reference numerals illustrate: C FP/CFN -feedback capacitor, C KC -anti-kickback capacitor, OR-anti-kickback OR gate, na/Nb-node of polar plate electrically connected with feedback chopper switch of amplifier, SW_CHP-feedback chopper switch, PCH 1-in-phase chopper phase signal, PCH 12-anti-phase chopper phase si