阅读说明：本技术 一种应用于电容式加速度计的可编程增益放大器 (A kind of programmable gain amplifier applied to capacitive accelerometer ) 是由 刘云涛 赵文博 杨璐 郭书宏 于 2019-09-18 设计创作，主要内容包括：本发明公开了一种应用于电容式加速度计的可编程增益放大器,属于MEMS惯性器件领域。采用开关电容结构,主要由开关,电容,可变电容阵列,运算放大器组成。通过分时复用、分时输出实现开关电容可编程增益放大器的连续信号输出,并实现全差分电路结构；通过相关双采样技术消除低频噪声和失调；可变电容阵列的n个电容呈指数分布,利用程序控制可变电容阵列来实现2<Sup>n</Sup>种不同的电容值,可变电容阵列选择采样电容而不是反馈电容,避免对放大器性能的影响。本发明可以实现2<Sup>n</Sup>种可调增益,大大提高了电路精度,能够适用于不同的电容式加速度传感器敏感结构,并实现多量程检测。(The invention discloses a kind of programmable gain amplifiers applied to capacitive accelerometer, belong to MEMS inertia device field.Using Switch capacitor structure, mainly by switching, capacitor, variable capacitor array, operational amplifier composition.The continuous signal output of switching capacity programmable gain amplifier is realized by time-sharing multiplex, timesharing output, and realizes full-differential circuits structure；Low-frequency noise and imbalance are eliminated by Correlated Double Sampling；N capacitor of variable capacitor array is exponentially distributed, and realizes 2 using process control variable capacitor array n The different capacitance of kind, variable capacitor array select sampling capacitance rather than feedback capacity, avoid the influence to amplifier performance.The present invention may be implemented 2 n Kind adjustable gain, substantially increases circuit precision, can be suitable for different capacitance acceleration transducer sensitive structures, and realizes that multrirange detects.)

1. a kind of programmable gain amplifier applied to capacitive accelerometer, it is characterised in that:

Component is Switch capacitor structure, including switch: P1 (301), P2 (302), P3 (303), P4 (304), P5 (307), P6 (308)、P7(309)、P8(310)、P9(311)、P10(312)、P11(313)、P12(314)、P13(315)、P14(316)、 P15(317)、P16(320)、P17(321)、P18(324)、P19(325)、P20(327)、P21(328)、P22(330)、P23 (331),P24(333),P25(334),P26(336),P27(337),P28(338),P29(339),P30(340)；Capacitor: C3 (318),C4(319),C5(322),C6(323),C7(326),C8(329),C9(332),C10(335)；Variable capacitor array: CAP ARRAY1(305),CAP ARRAY2(306)；Operational amplifier: OPA1 (341), OPA2 (342).

2. a kind of programmable gain amplifier applied to capacitive accelerometer according to claim 1, feature exist In:

One end connection Differential Input of P1 (301), P2 (302), one end connection the common-mode voltage VCM, P5 of P3 (303), P4 (304) (307), one end connection the common-mode voltage VCM, P7 of P6 (308), P11 (313), P12 (314), P13 (315), P14 (316) (309), P8 (310), P9 (311), P10 (312) one end be connected to C3 (318), C4 (319), C5 (322), C6 (323) One end, P15 (317) both ends are separately connected C3 (318) and C7 (326), and P16 (320) both ends are separately connected C4 (319) and C8 (329), P17 (321) both ends are separately connected C5 (322) and P24 (333), and P18 (324) both ends are separately connected C6 (323) and C10 (335), P19 (325) both ends are connected to the both ends of (326) C7, and P22 (330) both ends are connected to the both ends of (329) C8, P23 (331) both ends are connected to the both ends of (332) C9, and P26 (336) both ends are connected to the both ends of (335) C10, the both ends of P20 (327) It is connected to the positive input and difference output end of OPA1 (341), the both ends of switch P24 (333) are being connected to OPA2 (342) just To input terminal and difference output end, the both ends of P21 (328) are connected to the negative input and difference output end of OPA1 (341), The both ends of P25 (334) are connected to the negative input and difference output end of OPA2 (342), P27 (337), (338) both ends P28 point Not Lian Jie the difference output end of OPA1 (341) and the output end of gain amplifier, P29 (339), P30 (340) both ends are separately connected The difference output end of operational amplifier OPA2 (342) and the output end of gain amplifier.

3. a kind of programmable gain amplifier applied to capacitive accelerometer according to claim 1, feature exist In:

C3 (318) one end is connected to the positive input of (341) OPA1, and the negative sense that C4 (319) one end is connected to OPA1 (341) is defeated Enter end, C5 (322) one end is connected to the positive input of (342) OPA2, and C6 (323) one end is connected to operational amplifier OPA2 (342) negative input, C7 (326), C8 (329) one end be connected to the difference output end of (341) OPA1, C9 (332), One end of C10 (335) is connected to the difference output end of (342) OPA2.

4. a kind of programmable gain amplifier applied to capacitive accelerometer according to claim 1, feature exist In:

CAP ARRAY1 (305) both ends are connected with P3 (303), P5 (307) respectively, variable capacitor array CAP ARRAY2 (306) Both ends are connected with P4 (304), P6 (308) respectively.

5. a kind of programmable gain amplifier applied to capacitive accelerometer according to claim 1, feature exist In:

OPA1 (341) and OPA2 (342) is Full differential operational amplifier, and C3 (318), C4 (319), C5 (322), C6 (323) are Correlated double sampling capacitor, C7 (326), C8 (329) and C9 (332), C10 (335) are respectively OPA1 (341) and OPA2 (342) Feedback capacity.

6. a kind of programmable gain amplifier applied to capacitive accelerometer according to claim 1, feature exist In:

CAP ARRAY1 (305) and CAP ARRAY2 (306) are made of n capacitor respectively, capacitor C₀~C_nIt is exponentially distributed, greatly Small is respectively C₀×2⁰, C₀×2¹…C₀×2ⁿ, C₀For unit compensating electric capacity.

Technical field

The invention belongs to MEMS inertia device fields, and in particular to a kind of programmable increasing applied to capacitive accelerometer Beneficial amplifier.

Background technique

Sensor technology is one of the new and high technology that a world today attracts people's attention and grows rapidly, and is contemporary section The important symbol that technology is grown rapidly.The information that sensor can will test be converted to according to certain rules electric signal or its The information output of form needed for him is required with transmission, processing, storage, the record etc. that meet information.Acceleration transducer is sensing One important branch of device.Acceleration transducer can detect acceleration physical signal, high-precision acceleration sensing Device is widely used in automotive safety, earthquake detection, and aerospace etc. needs in high-precision fields of measurement.Capacitance acceleration Sensor is a kind of acceleration transducer of current most study.The research and development of acceleration transducer interface circuit are acceleration sensings The important component of device research.The minisize condenser type acceleration sensor outputs signals made of MEMS technology are very micro- It is weak, therefore the research and design of small signaling interface detection circuit have the practical significance for realizing sensor.

As MEMS technology develops, interface circuit signal processing circuit is towards high-precision, programmable, low noise, low-power consumption Development.There is provided herein a kind of high-precision programmable gain amplifiers applied to capacitive accelerometer.The amplifier is based on Switch capacitor structure realizes that continuous signal exports, and realizes fully differential structure using time-sharing multiplex, timesharing output, can effectively press down Common-mode noise processed.Using correlated double sampling technology, the imbalance and low-frequency noise of circuit are eliminated.Pass through program control switch capacitor battle array Column are to reach different amplification factors.

Summary of the invention

The purpose of the present invention is to provide high-precisions, programmable, low noise a kind of applied to capacitive accelerometer Programmable gain amplifier.

The purpose of the present invention is achieved through the following technical solutions:

A kind of programmable gain amplifier applied to capacitive accelerometer, mainly by switching: P1 (301, P2 (302, P3(303、P4(304、P5(307、P6(308、P7(309、P8(310、P9(311、P10(312、P11(313、P12(314、P13 (315、P14(316、P15(317、P16(320、P17(321、P18(324、P19(325、P20(327、P21(328、P22(330、 P23(331,P24(333,P25(334,P26(336,P27(337,P28(338,P29(339,P30(340；Capacitor: C3 (318, C4(319,C5(322,C6(323,C7(326,C8(329,C9(332,C10(335；Variable capacitor array: CAP ARRAY1 (305,CAP ARRAY2(306；Operational amplifier: OPA1 (341, OPA2 (342 compositions.

Wherein switch P1 (301, P2 (302 one end connects Differential Input, switch P3 (303, (304 one end connection is total to P4 Mode voltage VCM, switch P5 (307, P6 (308, P11 (313, P12 (314, P13 (315, P14 (316 one end connection common-mode voltage VCM, switch P7 (309, P8 (310, P9 (311, (312 one end is connected to correlated double sampling capacitor C3 (318, C4 to P10 (319, C5 (322, C6 (323 one end, switch P15 (317 both ends be separately connected correlated double sampling capacitor C3 (318 and feedback electricity Holding C7, ((320 both ends are separately connected correlated double sampling capacitor C4 (319 and feedback capacity C8 (329, switch P17 by 326, switch P16 (321 both ends are separately connected correlated double sampling capacitor C5, and (((324 both ends are separately connected 322 and feedback capacity P24 by 333, switch P18 (((325 both ends are connected to feedback capacity C7 (the two of 326 to 323 and feedback capacity C10 to correlated double sampling capacitor C6 by 335, switch P19 End, (330 both ends are connected to feedback capacity C8, and (329 both ends, (331 both ends are connected to feedback capacity C9 to switch P23 to switch P22 (332 both ends, (336 both ends are connected to feedback capacity C10, and (335 both ends, (327 both ends are connected to switch P20 switch P26 (341 positive input and difference output end, (333 both ends are connected to operational amplifier to switch P24 to operational amplifier OPA1 (342 positive input and difference output end, (328 both ends are connected to operational amplifier OPA1 (341 to switch P21 to OPA2 Negative input and difference output end, (334 both ends are connected to operational amplifier OPA2 (342 negative input to switch P25 And difference output end, switch P27 (337, P28 (338 both ends be separately connected operational amplifier OPA1 (341 difference output end and The output end of gain amplifier, switch P29 (339, (340 both ends are separately connected operational amplifier OPA2, and (342 difference is defeated by P30 The output end of outlet and gain amplifier.

(318 one end are connected to operational amplifier OPA1 (341 positive input, capacitor C4 (319 one end connection to capacitor C3 In operational amplifier OPA1, (341 negative input, (322 one end are connected to operational amplifier OPA2 (342 forward direction to capacitor C5 Input terminal, (323 one end are connected to operational amplifier OPA2 (342 negative input, capacitor C7 (326, C8 (329 to capacitor C6 One end be connected to operational amplifier OPA1 (341 difference output end, capacitor C9 (332, (335 one end is connected to operation and puts C10 Big device OPA2 (342 difference output end.

Variable capacitor array CAP ARRAY1 (305 both ends respectively with switch P3 (303, (307 are connected P5, variable capacitance battle array Arrange CAP ARRAY2 (306 both ends respectively with switch P4 (304, (308 are connected P6, are programmed to realize different capacitors Value.

The beneficial effects of the present invention are:

A kind of programmable gain amplifier applied to capacitive accelerometer is realized by time-sharing multiplex, timesharing output The continuous signal of switching capacity programmable gain amplifier exports, and realizes full-differential circuits structure；Pass through correlated-double-sampling skill Art eliminates low-frequency noise and imbalance；N capacitor of variable capacitor array is exponentially distributed, and utilizes process control variable capacitor array To realize 2ⁿThe different capacitance of kind.Variable capacitor array selects sampling capacitance rather than feedback capacity, avoids to amplifier The influence of energy.The present invention may be implemented 2ⁿKind adjustable gain, substantially increases circuit precision, can be suitable for different condenser types Acceleration transducer sensitive structure, and realize that multrirange detects.

Detailed description of the invention

Fig. 1 is high-precision programmable gain amplifier circuit figure of the invention；

Fig. 2 is working timing figure of the invention；

Fig. 3 is variable capacitor array；

Specific embodiment

Specific embodiments of the present invention will be further explained with reference to the accompanying drawing:

Fig. 1 is high-precision programmable gain amplifier of the invention, mainly by switch P1 (301, P2 (302, P3 (303, P4 (304、P5(307、P6(308、P7(309、P8(310、P9(311、P10(312、P11(313、P12(314、P13(315、P14 (316、P15(317、P16(320、P17(321、P18(324、P19(325、P20(327、P21(328、P22(330、P23(331、 P24(333,P25(334,P26(336,P27(337,P28(338,P29(339,P30(340；Capacitor C3 (318, C4 (319, C5 (322,C6(323,C7(326,C8(329,C9(332,C10(335；Variable capacitor array CAP ARRAY1 (305, CAP ARRAY2(306；Operational amplifier OPA1 (341, OPA2 (342 compositions.Wherein switch P1 (301, P2 (302 one end connection it is poor Divide input, switch P3 (303, P4 (304 one end connection common-mode voltage VCM.(305 both ends variable capacitor array CAP ARRAY1 Respectively with switch P3 (303, P5 (307 are connected, variable capacitor array CAP ARRAY2 (306 both ends respectively with switch P4 (304, P6 (308 are connected, and are programmed to realize different capacitances.Switch P5 (307, P6 (308, P11 (313, P12 (314, P13 (315, (316 one end connection common-mode voltage VCM, switch P7 (309, P8 (310, P9 (311, P10 (312 one end difference P14 Be connected to correlated double sampling capacitor C3 (318, C4 (319, C5 (322, (323 one end, (317 both ends are separately connected switch P15 C6 (((320 both ends are separately connected correlated double sampling capacitor C4 to 318 and feedback capacity C7 to correlated double sampling capacitor C3 by 326, switch P16 (((321 both ends are separately connected correlated double sampling capacitor C5 (322 and feedback capacity P24 to 319 and feedback capacity C8 by 329, switch P17 ((324 both ends are separately connected correlated double sampling capacitor C6 (323 and feedback capacity C10 (335, switch P19 (325 by 333, switch P18 Both ends are connected to feedback capacity C7, and (326 both ends, (330 both ends are connected to feedback capacity C8 (329 both ends, switch to switch P22 (331 both ends are connected to feedback capacity C9, and (332 both ends, (336 both ends are connected to feedback capacity C10 (335 to switch P26 to P23 Both ends, (327 both ends are connected to operational amplifier OPA1 (341 positive input and difference output end, switch to switch P20 (333 both ends are connected to operational amplifier OPA2 (342 positive input and difference output end, switch P21 (the two of 328 to P24 End is connected to operational amplifier OPA1, and (341 negative input and difference output end, (334 both ends are connected to fortune to switch P25 Calculate amplifier OPA2 (342 negative input and difference output end, switch P27 (337, (338 both ends are separately connected operation to P28 Amplifier OPA1 (341 difference output end and the output end of gain amplifier, switch P29 (339, (340 both ends connect P30 respectively Connect operational amplifier OPA2 (342 difference output end and the output end of gain amplifier.(318 one end are connected to operation to capacitor C3 (341 positive input, (319 one end are connected to operational amplifier OPA1 (341 negative sense input to capacitor C4 to amplifier OPA1 End, (322 one end are connected to operational amplifier OPA2, and (342 positive input, (323 one end are connected to fortune to capacitor C6 to capacitor C5 Calculate amplifier OPA2 (342 negative input, capacitor C7 (326, (329 one end is connected to operational amplifier OPA1 (341 to C8 Difference output end, capacitor C9 (332, (335 one end is connected to operational amplifier OPA2 (342 difference output end to C10.It is logical Cross time-sharing multiplex, timesharing output realizes that the continuous signal of switching capacity programmable gain amplifier exports, and realizes fully differential electricity Line structure；Low-frequency noise and imbalance are eliminated by Correlated Double Sampling；N capacitor of variable capacitor array is exponentially distributed, 2 are realized using process control variable capacitor arrayⁿThe different capacitance of kind, may be implemented 2ⁿKind adjustable gain, substantially increases Circuit precision.

Fig. 2 is working timing figure of the invention, and clock signal S1, S2, S3, S4, S5, S6 control programmable gain amplifier The operation that input signal sampling, electric charge transfer and output are kept is carried out, programmable-gain is realized by time-sharing multiplex, timesharing output The continuous signal of amplifier exports.

Fig. 3 is variable capacitor array, and the amplification factor of switching capacity type programmable gain amplifier is with sampling capacitance and instead It is related to feed the ratio held.The present invention devises one group of variable capacitor array to realize different sampling capacitance values.Wherein capacitor C₀~C_nIt is exponentially distributed, respectively C₀×2⁰, C₀×2¹…C₀×2ⁿ, C₀For unit compensating electric capacity.What the present invention designed can power transformation Holding array can make programmable gain amplifier realize different adjustable gains, substantially increase the precision of amplifier.

Two parts carry out input letter under clock signal S1, S2, S3, S4, S5, S6 effect to programmable gain amplifier up and down Number sampling, electric charge transfer and output keep operation.Two parts alternately, are realized and can be compiled by time-sharing multiplex, timesharing output The continuous signal of journey gain amplifier exports.((342 be Full differential operational amplifier, CAP ARRAY1 to 341 and OPA2 to OPA1 (305 and CAP ARRAY2 (306 be variable capacitor array, selects different capacitances to be connected in circuit by external program, Realize different gains.Capacitor C3 (318, C4 (319, C5 (322, C6 (323 be correlated double sampling capacitor, for eliminating circuit Low-frequency noise and imbalance, C7 (326, C8 (329 and C9 (332, C10 (335 be respectively Full differential operational amplifier OPA1 (341 Hes OPA2 (342 feedback capacity.

Circuit top half: S4 connects the entire lower half portion of low level and disconnects.S1 connects high level, variable capacitor array when sampling ((306 (are replaced respectively with C1 and C2 to input signal PGA_IN and PGA_IP 305 and CAP ARRAY2 CAP ARRAY1 in formula It is sampled；S5 connects high level, and the offset voltage and 1/f noise of fully-differential amplifier are stored in correlated double sampling capacitor C3 (318 (((329 charges are reset 326 and C8 by 319, feedback capacity C7 with C4；S6 and S2 connect low level.Node A charge is (V_CM-V_INC₁, knot Point B charge (V_CM-V_IPC₂.S1, S5 connect low level when electric charge transfer, and S6 connects high level, because of correlated double sampling capacitor C3 (318 Hes C4 (cancel out each other with circuit offset voltage, so variable capacitor array CAP ARRAY1 (305 and CAP ARRAY2 by 319 voltage (306 charge is transferred completely into (the 326 and C8 (329 of C7 in feedback capacity.S1, S2 connect high level when output is kept, and S5, S6 connect Low level, while variable capacitor array samples input, ((voltage on 329 keeps defeated to 326 and C8 to feedback capacity C7 Out.Above procedure can be obtained according to law of conservation of charge:

Wherein V_OUT1PFor operational amplifier OPA1, (341 forward direction is exported, wherein V_OUT1NFor operational amplifier OPA1 (341 Negative sense output.C1=C2=CS, C7=C8=CF.Two formulas in formula (1) are subtracted each other and can be obtained:

(V_A-V_B)C₁+(V_A-V_B)C_F-(V_OUT1P-V_OUT1N)C_F=(V_IP-V_IN)C_S (2)

Wherein A_u1For operational amplifier OPA1 (341 gain, if A_u1→ ∞, V_A-V_B=0, it can obtain

Circuit lower half portion: S6 connects the entire top half of low level and disconnects.The output of circuit top half can while holding Becoming capacitor array CAP ARRAY1, ((306 (are replaced respectively with C1 and C2 to input signal PGA_ 305 and CAP ARRAY2 in formula IN and PGA_IP are sampled, and S1 connects high level, and S3 connects high level, offset voltage and the 1/f noise storage of fully-differential amplifier In correlated double sampling capacitor C5, ((((335 charges are reset 332 and C10 322 and C6 by 323, feedback capacity C9；S4 meets low level, S2 Connect high level.Node A charge is (V_CM-V_INC₁), node B charge (V_CM-V_IPC₂).S1, S3 meet low level, S4 when electric charge transfer High level is connect, because correlated double sampling capacitor C5 ((cancel out each other 322 and C6 with circuit offset voltage, can by 323 voltage Becoming capacitor array CAP ARRAY1, ((306 charge is transferred completely into (the 332 and C10 of C9 in feedback capacity to 305 and CAP ARRAY2 (335.S2, S3, S6 connect low level when output is kept, and S1 connects high level, while variable capacitor array samples input, ((voltage on 335 keeps output to 332 and C10 to feedback capacity C9.Above procedure can be obtained according to law of conservation of charge:

Wherein V_OUT2PFor operational amplifier OPA2, (342 forward direction is exported, wherein V_OUT2NFor operational amplifier OPA2 (342 Negative sense output.C1=C2=CS, C9=C10=CF.Two formulas in formula (1) are subtracted each other and can be obtained:

(V_A-V_B)C₁+(V_A-V_B)C_F-(V_OUT2N-V_OUT2P)C_F=(V_IP-V_IN)C_S (6)

Wherein A_u2For operational amplifier OPA2 (342 gain, if A_u2→ ∞, V_A-V_B=0, it can obtain

Operational amplifier OPA1 (341 and OPA2 (342 output size equal direction phase can be obtained according to formula (4) and (8) Instead.Both clock controls working condition alternately, the company of programmable gain amplifier is realized by time-sharing multiplex, timesharing output Continuous signal output.

By process control variable capacitor array CAP ARRAY1, ((306 may be implemented 2 to 305 and CAP ARRAY2ⁿKind is not Same capacitance.Different amplification factors can be obtained according to formula (4) the CS capacitance different with (8) selection, and then realize 2ⁿ Kind adjustable gain, substantially increases circuit precision.

The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field For art personnel, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any to repair Change, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.