WO2011063101A1 - Chopper stabilized amplifier with filtering - Google Patents

Chopper stabilized amplifier with filtering Download PDF

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Publication number
WO2011063101A1
WO2011063101A1 PCT/US2010/057199 US2010057199W WO2011063101A1 WO 2011063101 A1 WO2011063101 A1 WO 2011063101A1 US 2010057199 W US2010057199 W US 2010057199W WO 2011063101 A1 WO2011063101 A1 WO 2011063101A1
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WO
WIPO (PCT)
Prior art keywords
amplifier circuit
chopper stabilized
output
stabilized amplifier
low pass
Prior art date
Application number
PCT/US2010/057199
Other languages
French (fr)
Inventor
Eric Blackall
Ross Teggatz
Original Assignee
Triune Ip Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Triune Ip Llc filed Critical Triune Ip Llc
Priority to EP10832164A priority Critical patent/EP2502344A4/en
Publication of WO2011063101A1 publication Critical patent/WO2011063101A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/38—DC amplifiers with modulator at input and demodulator at output; Modulators or demodulators specially adapted for use in such amplifiers
    • H03F3/387—DC amplifiers with modulator at input and demodulator at output; Modulators or demodulators specially adapted for use in such amplifiers with semiconductor devices only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/005—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements using switched capacitors, e.g. dynamic amplifiers; using switched capacitors as resistors in differential amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/168—Two amplifying stages are coupled by means of a filter circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/261—Amplifier which being suitable for instrumentation applications
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45138—Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45512—Indexing scheme relating to differential amplifiers the FBC comprising one or more capacitors, not being switched capacitors, and being coupled between the LC and the IC
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H19/00—Networks using time-varying elements, e.g. N-path filters
    • H03H19/004—Switched capacitor networks

Definitions

  • the invention relates to amplifier circuits and systems used in electronics and integrated circuitry. More particularly, the invention relates to chopper stabilization and noise reduction in operational amplifier circuits and associated systems.
  • the invention provides chopper stabilized amplifier circuitry and techniques having integrated filters for noise reduction.
  • the embodiments described herein are intended to be exemplary and not exclusive. Variations in the practice of the invention are possible and preferred embodiments are illustrated and described for the purposes of clarifying the invention. All possible variations within the scope of the invention cannot, and need not, be shown.
  • a chopper stabilized amplifier circuit includes a gain stage having both an input and an output equipped with chopping circuitry such that an input signal may be chopped prior to reaching the gain stage and an intermediate signal output by the gain stage may also be chopped prior to reaching the output of the chopper stabilized amplifier circuit. Integrator circuitry and a low pass filter are interposed between the gain stage output chopping circuitry and the chopper stabilized amplifier circuit output. This arrangement provides a chopper stabilized amplifier circuit adapted for producing an output signal having relatively minor ripple noise.
  • a chopper stabilized amplifier circuit as described above includes a transconductance operational amplifier within the gain stage circuitry.
  • a chopper stabilized amplifier circuit as described above includes low pass filter circuitry in a switched capacitor filter configuration.
  • a technique for amplifying a signal includes steps for receiving and chopping an input signal, and thereafter amplifying the chopped input signal to produce an intermediate signal.
  • the intermediate signal is also chopped, integrated, and filtered to reduce ripple noise, resulting in an output signal.
  • a filtering step also includes a step of sampling the intermediate signal synchronously with the chopping frequency.
  • the above-described method includes a filtering step of sampling the intermediate signal at twice the chopping frequency.
  • the above-described method may include a variation in which the filtering step further includes sampling the intermediate signal at a frequency lower than the chopping frequency.
  • steps include receiving and chopping an input signal, and thereafter amplifying the chopped input signal to produce an intermediate signal.
  • the intermediate signal is integrated and filtered to reduce ripple noise by operating a transconductance-capacitor low pass filter.
  • the invention has advantages including but not limited to providing one or more of the following features, low noise, low offset voltage, and high efficiency in stable amplifier circuitry.
  • Figure 1 is a schematic diagram of a preferred embodiment of a chopper stabilized amplifier circuit with integrated filter
  • Figure 2 is a schematic diagram of an exemplary preferred embodiment of a filter component of the circuit introduced in Figure 1 ;
  • Figure 3 is a schematic diagram of an alternative preferred embodiment of a chopper stabilized amplifier circuit according to the invention.
  • a chopper stabilized amplifier having filtering circuitry is shown 100.
  • the circuitry 100 typically includes inputs 102 for receiving input signals from an associated system and an output 104 for outputting an amplified signal.
  • the input signals are within the range of about 0.01 Hz to about 10 Hz, such as those common in low-power sensor applications, although other frequency ranges may be suitable in other applications.
  • the amplifier circuit 100 preferably has two internal signal paths.
  • a first signal path 106 includes operational amplifiers, preferably transconductance operational amplifiers: gml; gm2; and gm3, as shown.
  • a second signal path 108 preferably includes operational amplifier gm4, and also gm3.
  • a gain stage 107 is included in the first signal path 106, here implemented with operational amplifier gml, the gain stage 107 has its inputs 110 and outputs 112 chopped.
  • the effect of this chopper stabilized amplifier gml on the chopped input signal is to provide gain while minimizing noise and offset.
  • this method of cancelling offset creates ripple noise at the chopping frequency of the intermediate signal at the output 112 of the gain stage amplifier gml .
  • integrator circuitry 113 herein implemented with capacitive filter CI , is connected to the output 112 of the gain stage 107.
  • the integrator circuitry 113 is connected to an active low pass filter 120 which integrates and filters the sampled error further reducing output ripple noise.
  • the integrator circuitry 113 is preferably sampled at the chopping frequency, greatly reducing output ripple noise in the intermediate signal at the gain stage gml output 112.
  • the low pass filter circuitry 120 in presently preferred embodiments is implemented in a switched capacitor filter configuration adapted for sampling in synchronization with the chopping frequency. The filtered, integrated, chopped, gain stage output signal is subsequently conducted to the output 104 of the chopper stabilized amplifier circuit 100.
  • the low pass filter 120 preferably samples the intermediate signal output of the gain stage 107 ( Figure 1) at twice the chopping frequency, significantly reducing output ripple noise.
  • the low pass filter 120 may be adjusted for gain and cut-off frequency.
  • the example shown and described herein may in some instances be implemented in combination with other topologies, for example the topology shown in Figure 1, without departure from the principles of the invention.
  • the low pass filter circuitry 120 may optionally be configured with a cutoff frequency lower than the chopping frequency, achieving increased noise reduction at the expense of tolerating more ripple.
  • FIG. 3 Another example of a preferred embodiment of a chopper stabilized amplifier circuit with integrated filtering is shown in the simplified schematic of Figure 3.
  • the circuit 300 uses a low pass transconductance-capacitive (gm-C) filter 302 to reduce output ripple noise.
  • the low pass gm-C filter 302 is created by coupling an operational amplifier gm6 and an integrating capacitive filter C2 as shown in the example, or equivalent circuits.
  • Operational amplifier gm6 has its inputs and outputs chopped.
  • the gm-C filter low pass cut-off frequency is selected to be much lower than the chopping frequency in order to greatly reduce output ripple noise.
  • the capacitor C2 integrates the output of gm6 over time.
  • C2 creates the further benefits of allowing for higher chopping frequencies, facilitating the use of ultra-low currents in the circuit 300.
  • the use of ultra- low currents is advantageous in applications for which the level of energy consumption is a concern.
  • the chopper stabilized amplifier circuit 100 may include one or more stabilizing capacitor C3 operably coupled with the low pass filter circuitry 120.
  • the chopper stabilized amplifier circuit 100 may include one or more stabilizing capacitor C3 operably coupled with the low pass filter circuitry 120.
  • circuits and methods of the invention provide one or more advantages including but not limited to one or more of; greatly reducing output ripple noise otherwise found in chopper stabilized amplifiers, and reduced costs. While the invention has been described with reference to certain illustrative embodiments, those described herein are not intended to be construed in a limiting sense. For example, variations or combinations of features or materials in the embodiments shown and described may be used in particular cases without departure from the invention. Although the presently preferred embodiments are described herein in terms of particular examples, modifications and combinations of the illustrative embodiments as well as other advantages and embodiments of the invention will be apparent to persons skilled in the arts upon reference to the drawings, description, and claims.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)

Abstract

The disclosed invention provides chopper stabilized amplifier circuitry (100) having a gain stage (107). The input (110) and output (112) of the gain stage (107) are each chopped. Integrator circuitry (113) is provided the chopped gain stage output signal may be integrated, and low pass filter circuitry (120) is operably coupled between the integrator (113) and the chopper stabilized amplifier circuit output (104), whereby the signal may be sampled, filtered, and conducted to the output (104).

Description

CHOPPER STABLIZED AMPLIFIER WITH FILTERING
PRIORITY ENTITLEMENT
[001] This application is entitled to priority based on Provisional Patent Application Serial Number 61/262,484 filed on November 18, 2009. This application and the Provisional Patent Application have at least one common inventor.
TECHNICAL FIELD
[002] The invention relates to amplifier circuits and systems used in electronics and integrated circuitry. More particularly, the invention relates to chopper stabilization and noise reduction in operational amplifier circuits and associated systems.
BACKGROUND OF THE INVENTION
[003] In integrated circuit operational amplifiers it is desirable to have a low offset voltage, low offset drift, low noise, and a stable output signal. To some extent, these sought-after characteristics can be contradictory. An auto-zeroing approach is sometimes used, providing low ripple noise at the expense of higher in-band noise. Auto-zeroing techniques also tend to have substantially higher quiescent current requirements relative to chopper stabilized circuits. A chopper stabilization approach can generally provide lower in-band noise and lower offset drift, but with a relatively higher ripple noise level.
[004] Due to the foregoing and possibly additional problems, improved apparatus and systems and related methods for chopper stabilized amplifiers having low offset and low noise, particularly low ripple noise, would be a useful contribution to the arts.
SUMMARY OF THE INVENTION
[005] In carrying out the principles of the present invention, in accordance with preferred embodiments, the invention provides chopper stabilized amplifier circuitry and techniques having integrated filters for noise reduction. The embodiments described herein are intended to be exemplary and not exclusive. Variations in the practice of the invention are possible and preferred embodiments are illustrated and described for the purposes of clarifying the invention. All possible variations within the scope of the invention cannot, and need not, be shown.
[006] According to one aspect of the invention, in a preferred embodiment, a chopper stabilized amplifier circuit includes a gain stage having both an input and an output equipped with chopping circuitry such that an input signal may be chopped prior to reaching the gain stage and an intermediate signal output by the gain stage may also be chopped prior to reaching the output of the chopper stabilized amplifier circuit. Integrator circuitry and a low pass filter are interposed between the gain stage output chopping circuitry and the chopper stabilized amplifier circuit output. This arrangement provides a chopper stabilized amplifier circuit adapted for producing an output signal having relatively minor ripple noise.
[007] According to another aspect of the invention, in a preferred embodiment thereof, a chopper stabilized amplifier circuit as described above includes a transconductance operational amplifier within the gain stage circuitry.
[008] According to another aspect of the invention, in a preferred embodiment thereof, a chopper stabilized amplifier circuit as described above includes low pass filter circuitry in a switched capacitor filter configuration.
[009] According to another aspect of the invention, in a preferred method thereof, a technique for amplifying a signal includes steps for receiving and chopping an input signal, and thereafter amplifying the chopped input signal to produce an intermediate signal. The intermediate signal is also chopped, integrated, and filtered to reduce ripple noise, resulting in an output signal.
[010] According to yet another aspect of the invention, in a preferred implementation of the embodiment described immediately above, a filtering step also includes a step of sampling the intermediate signal synchronously with the chopping frequency.
[Oil] According to still another aspect of the invention, the above-described method includes a filtering step of sampling the intermediate signal at twice the chopping frequency.
[012] According to another aspect of the invention, the above-described method may include a variation in which the filtering step further includes sampling the intermediate signal at a frequency lower than the chopping frequency.
[013] According to another aspect of the invention, in preferred method embodiments, steps include receiving and chopping an input signal, and thereafter amplifying the chopped input signal to produce an intermediate signal. The intermediate signal is integrated and filtered to reduce ripple noise by operating a transconductance-capacitor low pass filter.
[014] The invention has advantages including but not limited to providing one or more of the following features, low noise, low offset voltage, and high efficiency in stable amplifier circuitry. These and other advantages, features, and benefits of the invention can be understood by one of ordinary skill in the arts upon careful consideration of the detailed description of representative embodiments of the invention in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[015] The present invention may be more clearly understood from consideration of the description and drawings in which:
[016] Figure 1 is a schematic diagram of a preferred embodiment of a chopper stabilized amplifier circuit with integrated filter; [017] Figure 2 is a schematic diagram of an exemplary preferred embodiment of a filter component of the circuit introduced in Figure 1 ; and
[018] Figure 3 is a schematic diagram of an alternative preferred embodiment of a chopper stabilized amplifier circuit according to the invention.
[019] References in the detailed description correspond to like references in the various drawings unless otherwise noted. Descriptive and directional terms used in the written description such as front, back, top, bottom, upper, side, et cetera, refer to the drawings themselves as laid out on the paper and not to physical limitations of the invention unless specifically noted. The drawings are not to scale, and some features of embodiments shown and discussed are simplified or amplified for illustrating principles and features as well as advantages of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[020] The making and using of various exemplary embodiments of the invention are discussed herein, but it should also be appreciated that the apparatus and techniques for its use exemplify inventive concepts which can be embodied in a wide variety of specific contexts. It should be understood that the embodiments of the invention may be practiced in various applications and implementations without altering the principles of the invention. For purposes of clarity, detailed descriptions of functions, components, and systems familiar to those skilled in the applicable arts are not included. In general, the invention provides circuits and methods for implementation of chopper stabilized amplifiers with noise reduction filtering. The invention is described in the context of representative example embodiments. Although variations and alternatives for the details of the embodiments are possible, each has one or more advantages over the prior art.
[021] Referring primarily to Figure 1, in an example of a preferred embodiment, a chopper stabilized amplifier having filtering circuitry is shown 100. The circuitry 100 typically includes inputs 102 for receiving input signals from an associated system and an output 104 for outputting an amplified signal. Preferably, the input signals are within the range of about 0.01 Hz to about 10 Hz, such as those common in low-power sensor applications, although other frequency ranges may be suitable in other applications. The amplifier circuit 100 preferably has two internal signal paths. A first signal path 106 includes operational amplifiers, preferably transconductance operational amplifiers: gml; gm2; and gm3, as shown. A second signal path 108 preferably includes operational amplifier gm4, and also gm3. A gain stage 107 is included in the first signal path 106, here implemented with operational amplifier gml, the gain stage 107 has its inputs 110 and outputs 112 chopped. The effect of this chopper stabilized amplifier gml on the chopped input signal is to provide gain while minimizing noise and offset. However, it has been found that this method of cancelling offset creates ripple noise at the chopping frequency of the intermediate signal at the output 112 of the gain stage amplifier gml . As a solution to this problem, integrator circuitry 113, herein implemented with capacitive filter CI , is connected to the output 112 of the gain stage 107. The integrator circuitry 113 is connected to an active low pass filter 120 which integrates and filters the sampled error further reducing output ripple noise. The integrator circuitry 113 is preferably sampled at the chopping frequency, greatly reducing output ripple noise in the intermediate signal at the gain stage gml output 112. The low pass filter circuitry 120 in presently preferred embodiments is implemented in a switched capacitor filter configuration adapted for sampling in synchronization with the chopping frequency. The filtered, integrated, chopped, gain stage output signal is subsequently conducted to the output 104 of the chopper stabilized amplifier circuit 100.
[022] Now referring primarily to Figure 2, an example of a preferred embodiment of an active low pass filter 120 is shown in a simplified schematic diagram. The low pass filter 120 preferably samples the intermediate signal output of the gain stage 107 (Figure 1) at twice the chopping frequency, significantly reducing output ripple noise. Preferably, the low pass filter 120 may be adjusted for gain and cut-off frequency. The example shown and described herein may in some instances be implemented in combination with other topologies, for example the topology shown in Figure 1, without departure from the principles of the invention. The low pass filter circuitry 120 may optionally be configured with a cutoff frequency lower than the chopping frequency, achieving increased noise reduction at the expense of tolerating more ripple.
[023] Another example of a preferred embodiment of a chopper stabilized amplifier circuit with integrated filtering is shown in the simplified schematic of Figure 3. The circuit 300 uses a low pass transconductance-capacitive (gm-C) filter 302 to reduce output ripple noise. The low pass gm-C filter 302 is created by coupling an operational amplifier gm6 and an integrating capacitive filter C2 as shown in the example, or equivalent circuits. Operational amplifier gm6 has its inputs and outputs chopped. The gm-C filter low pass cut-off frequency is selected to be much lower than the chopping frequency in order to greatly reduce output ripple noise. The capacitor C2 integrates the output of gm6 over time. Because the signal need not reach its final value during each chopping phase, C2 creates the further benefits of allowing for higher chopping frequencies, facilitating the use of ultra-low currents in the circuit 300. The use of ultra- low currents is advantageous in applications for which the level of energy consumption is a concern.
[024] Again referring primarily to Figure 1, the chopper stabilized amplifier circuit 100 may include one or more stabilizing capacitor C3 operably coupled with the low pass filter circuitry 120. Providing one or more stabilizing capacitors, e.g., C3, on the output side of the low pass filter 120, in which the filter output capacitance is significantly lower than the filter input capacitance, facilitates fast signal settling and stability in the operation of the gain stage 107.
[025] The circuits and methods of the invention provide one or more advantages including but not limited to one or more of; greatly reducing output ripple noise otherwise found in chopper stabilized amplifiers, and reduced costs. While the invention has been described with reference to certain illustrative embodiments, those described herein are not intended to be construed in a limiting sense. For example, variations or combinations of features or materials in the embodiments shown and described may be used in particular cases without departure from the invention. Although the presently preferred embodiments are described herein in terms of particular examples, modifications and combinations of the illustrative embodiments as well as other advantages and embodiments of the invention will be apparent to persons skilled in the arts upon reference to the drawings, description, and claims.

Claims

WE CLAIM:
1. A chopper stabilized amplifier circuit comprising:
a gain stage having an input and an output;
input chopping circuitry operably coupled to the gain stage input whereby a signal input to the chopper stabilized amplifier circuit may be chopped prior to reaching the gain stage;
output chopping circuitry operably coupled to the gain stage output whereby a signal output from the gain stage may be chopped prior to reaching the output of the chopper stabilized amplifier circuit;
integrator circuitry operably coupled between the output chopping circuitry and the chopper stabilized amplifier circuit output, whereby the chopped gain stage output signal may be integrated; and
low pass filter circuitry operably coupled between the integrator and the chopper stabilized amplifier circuit output, whereby the integrated chopped gain stage output signal may be sampled, filtered, and conducted to the output of the chopper stabilized amplifier circuit.
2. The chopper stabilized amplifier circuit according to claim 1 wherein the gain stage further comprises an operational amplifier.
3. The chopper stabilized amplifier circuit according to claim 1 wherein the gain stage further comprises a transconductance operational amplifier.
4. The chopper stabilized amplifier circuit according to claim 1 wherein the integrator circuitry further comprises a capacitor.
5. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry further comprises a switched capacitor filter.
6. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry is configured for sampling in synchronization with a chopping frequency.
7. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry is configured for sampling at a frequency twice a chopping frequency.
8. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry is configured for sampling at a frequency lower than a chopping frequency.
9. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry is configured to be adjustable for gain.
10. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry is configured to be adjustable for cutoff frequency.
11. The chopper stabilized amplifier circuit according to claim 1 wherein the low pass filter circuitry further comprises a transconductance operational amplifier operably coupled with a capacitor.
12. The chopper stabilized amplifier circuit according to claim 1 further comprising one or more stabilizing capacitor operably coupled with the low pass filter circuitry.
13. A method for amplifying a signal comprising the steps of:
receiving and chopping an input signal;
amplifying the chopped input signal to produce an intermediate signal;
chopping the intermediate signal;
integrating the intermediate signal to reduce ripple noise;
filtering the intermediate signal to further reduce ripple noise; and
providing the resulting amplified signal as an output.
14. The method according to claim 13 wherein the filtering step further comprises sampling the intermediate signal synchronously with the chopping frequency.
15. The method according to claim 13 wherein the filtering step further comprises sampling the intermediate signal at twice the chopping frequency.
16. The method according to claim 13 wherein the filtering step further comprises sampling at a frequency lower than a chopping frequency.
17. The method according to claim 13 wherein the filtering step further comprises operating a low pass filter to remove ripple signals.
18. The method according to claim 13 wherein the filtering step further comprises operating a switched capacitor low pass filter to remove ripple signals.
19. The method according to claim 13 wherein the filtering step further comprises operating a transconductance-capacitor filter to remove ripple signals.
20. The method according to claim 13 wherein the filtering step further comprises operating a transconductance-capacitor low pass filter to remove ripple.
PCT/US2010/057199 2009-11-18 2010-11-18 Chopper stabilized amplifier with filtering WO2011063101A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP10832164A EP2502344A4 (en) 2009-11-18 2010-11-18 Chopper stabilized amplifier with filtering

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US26248409P 2009-11-18 2009-11-18
US61/262,484 2009-11-18

Publications (1)

Publication Number Publication Date
WO2011063101A1 true WO2011063101A1 (en) 2011-05-26

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CN110474611A (en) * 2019-07-29 2019-11-19 深圳市锐能微科技有限公司 A kind of copped wave preamplifier and its design method

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US10063284B2 (en) 2014-03-04 2018-08-28 Triune Ip Llc Isolation for communication and power

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US20080018392A1 (en) * 2006-07-18 2008-01-24 Microchip Technology Incorporated Minimizing Switching Noise and its Effects in Auto-Zeroed Amplifiers
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Publication number Priority date Publication date Assignee Title
CN110474611A (en) * 2019-07-29 2019-11-19 深圳市锐能微科技有限公司 A kind of copped wave preamplifier and its design method
CN110474611B (en) * 2019-07-29 2023-07-14 深圳市锐能微科技有限公司 Chopper preamplifier and design method thereof

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EP2502344A1 (en) 2012-09-26
EP2502344A4 (en) 2013-03-13

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