Signal processing circuit and Hall detection device

Abstract

The invention discloses a signal processing circuit and a Hall detection device. The signal processing circuit comprises a chopper circuit; an amplification circuit; the amplifying circuit comprises at least one level of operational amplifier, and the last operational amplifier in the at least one level of operational amplifier is a driving level operational amplifier. One end of the first capacitor is connected with the first input end of the driving-stage operational amplifier, and the other end of the first capacitor is connected with the first output end of the driving-stage operational amplifier; and one end of the second capacitor is connected with the second input end of the driving-stage operational amplifier, and the other end of the second capacitor is connected with the second output end of the driving-stage operational amplifier. Based on the above mode, the size of the signal processing circuit can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of sensing signal processing, and particularly to a signal processing circuit and a Hall detection device. Background Art

[0002] In the prior art, after a Hall sensing initial signal is generated by a Hall sensing circuit, an amplification circuit and a chopper circuit are usually used to perform amplification processing and chopper processing on the Hall sensing initial signal to obtain a Hall sensing amplified signal with an increased frequency of the contained offset voltage signal. Usually, a corresponding analog filter also needs to be set to perform low-pass filtering on the Hall sensing amplified signal to obtain a Hall sensing amplified signal with the offset voltage signal filtered out. Subsequently, an analog-to-digital conversion can be performed based on the Hall sensing amplified signal to obtain a corresponding digital signal, completing Hall detection.

[0003] The defect of the prior art is that the volume occupied by an analog filter with a low-pass filtering function is too large, which in turn leads to a relatively large volume occupied by a signal processing circuit for processing the Hall sensing initial signal with a traditional structure. Summary of the Invention

[0004] The main technical problem to be solved by this application is how to reduce the volume of the signal processing circuit.

[0005] To solve the above technical problem, the first technical solution adopted by this application is: A signal processing circuit, comprising: A chopper circuit; An amplification circuit, the input end of the chopper circuit is used to connect to a Hall sensing circuit to receive a Hall sensing initial signal, the amplification circuit is used to perform amplification processing on the Hall sensing initial signal, and the chopper circuit is used to perform chopper processing on the Hall sensing initial signal after amplification processing to output a Hall sensing amplified signal; wherein, the amplification circuit includes: At least one stage of operational amplifier, the last operational amplifier in the at least one stage of operational amplifier is a driving stage operational amplifier; A first capacitor, one end of the first capacitor is connected to the first input end of the driving stage operational amplifier, and the other end of the first capacitor is connected to the first output end of the driving stage operational amplifier; A second capacitor, one end of the second capacitor is connected to the second input end of the driving stage operational amplifier, and the other end of the second capacitor is connected to the second output end of the driving stage operational amplifier.

[0006] Wherein, the signal processing circuit further includes a third capacitor; The first output end and the second output end of the chopper circuit jointly output the Hall sensing amplified signal, one end of the third capacitor is connected to the first output end of the chopper circuit, and the other end of the third capacitor is connected to the second output end of the chopper circuit, or, the first output end and the second output end of the amplification circuit jointly output the Hall sensing initial signal after amplification processing, one end of the third capacitor is connected to the first output end of the amplification circuit, and the other end of the third capacitor is connected to the second output end of the amplification circuit.

[0007] Among them, at least one stage of operational amplifier includes an input-stage operational amplifier, a summing-stage operational amplifier, and a driving-stage operational amplifier connected in sequence; the input terminal of the input-stage operational amplifier is connected to the output terminal of the driving-stage operational amplifier.

[0008] Among them, the positive input terminal of the input-stage operational amplifier is connected to the positive output terminal of the Hall sensing circuit, and the negative input terminal of the input-stage operational amplifier is connected to the negative output terminal of the Hall sensing circuit; the positive input terminal of the input-stage operational amplifier is connected to the positive output terminal of the driving-stage operational amplifier, and the negative input terminal of the input-stage operational amplifier is connected to the negative output terminal of the driving-stage operational amplifier.

[0009] Among them, the chopping circuit includes a first chopper and a second chopper, and at least one stage of operational amplifier includes at least two input-stage operational amplifiers; the input terminal of the first chopper is used to connect to the Hall sensing circuit to receive the initial Hall sensing signal, and the output terminal of the first chopper is respectively connected to the input terminals of each input-stage operational amplifier through corresponding switches. The output terminal of the input-stage operational amplifier is connected to the input terminal of the summing-stage operational amplifier, the output terminal of the summing-stage operational amplifier is connected to the input terminal of the driving-stage operational amplifier, the input terminals of each input-stage operational amplifier are respectively connected to the output terminal of the driving-stage operational amplifier through corresponding feedback branches, the output terminal of the driving-stage operational amplifier is connected to the input terminal of the second chopper, and the output terminal of the second chopper is used to output the amplified Hall sensing signal.

[0010] Among them, the number of at least two input-stage operational amplifiers is greater than the number of Hall sensing circuits, and each Hall sensing circuit is respectively connected to a corresponding input-stage operational amplifier through a corresponding first chopper; one of the at least two input-stage operational amplifiers serves as a feedback amplifier, and the input-stage operational amplifiers other than the feedback amplifier among the at least two input-stage operational amplifiers serve as gain amplifiers; the switch between the input terminal of the gain amplifier and the corresponding first chopper is turned on, and the switches between the input terminals of each gain amplifier and the output terminal of the driving-stage operational amplifier are turned off; the switch between the input terminal of the feedback amplifier and the output terminal of the driving-stage operational amplifier is turned on, and the switch between the input terminal of the feedback amplifier and the corresponding first chopper is turned off.

[0011] Among them, within a preset period, at every interval of a preset duration, the feedback amplifier is updated to one of the at least two input-stage operational amplifiers that has not served as a feedback amplifier within this preset period.

[0012] Among them, within a preset period, every other preset duration: update the feedback amplifier to an input-stage operational amplifier among at least two input-stage operational amplifiers that has not served as the feedback amplifier within this preset period, and switch the gain amplifier connected to the corresponding Hall sensing circuit to connect to a Hall sensing circuit that has not been connected within this preset period.

[0013] Among them, at least one stage of operational amplifier includes a first input-stage operational amplifier and a second input-stage operational amplifier; the first input terminal of the first chopper is used to connect to the first output terminal of the Hall sensing circuit, and the second input terminal of the first chopper is used to connect to the second output terminal of the Hall sensing circuit; the first output terminal of the first chopper is connected to the first input terminal of the first input-stage operational amplifier through a corresponding switch, the second output terminal of the first chopper is connected to the second input terminal of the first input-stage operational amplifier through a corresponding switch, the first output terminal of the first chopper is connected to the first input terminal of the second input-stage operational amplifier through a corresponding switch, and the second output terminal of the first chopper is connected to the second input terminal of the second input-stage operational amplifier through a corresponding switch; the first input terminal of the summing-stage operational amplifier is respectively connected to the first output terminal of the first input-stage operational amplifier and the first output terminal of the second input-stage operational amplifier, and the second input terminal of the summing-stage operational amplifier is respectively connected to the second output terminal of the first input-stage operational amplifier and the second output terminal of the second input-stage operational amplifier; the first input terminal of the driving-stage operational amplifier is connected to the first output terminal of the summing-stage operational amplifier, and the second input terminal of the driving-stage operational amplifier is connected to the second output terminal of the summing-stage operational amplifier; the first input terminal of the second chopper is connected to the first output terminal of the driving-stage operational amplifier, the second input terminal of the second chopper is connected to the second output terminal of the driving-stage operational amplifier, and the first output terminal and the second output terminal of the second chopper are used to jointly output the Hall sensing amplified signal; the first input terminal of the second chopper is connected to the second input terminal of the first input-stage operational amplifier through a first feedback branch, the second input terminal of the second chopper is connected to the first input terminal of the first input-stage operational amplifier through a second feedback branch, the first input terminal of the second chopper is connected to the second input terminal of the second input-stage operational amplifier through a third feedback branch, and the second input terminal of the second chopper is connected to the first input terminal of the second input-stage operational amplifier through a fourth feedback branch.

[0014] Among them, the signal processing circuit further includes a first resistor, a second resistor, a third resistor, and a fourth resistor; a first input terminal of the second chopper is connected to one end of the first resistor, a second input terminal of the second chopper is connected to one end of the second resistor, one end of the third resistor is connected to the other end of the first resistor, the other end of the third resistor and one end of the fourth resistor are respectively connected to a preset reference voltage, and the other end of the fourth resistor is connected to the other end of the second resistor; the other end of the first resistor is connected to a second input terminal of the first input-stage operational amplifier through a first feedback branch; the other end of the first resistor is connected to a second input terminal of the second input-stage operational amplifier through a second feedback branch; the other end of the second resistor is connected to a first input terminal of the first input-stage operational amplifier through a third feedback branch; the other end of the second resistor is connected to a first input terminal of the second input-stage operational amplifier through a fourth feedback branch.

[0015] To solve the above technical problems, the second technical solution adopted in this application is: a Hall detection device, including: a Hall sensing circuit; the above-mentioned signal processing circuit, and the signal processing circuit is connected to the Hall sensing circuit.

[0016] The beneficial effect of this application lies in: different from the prior art, in the technical solution of this application, the signal processing circuit includes a chopping circuit and an amplifying circuit. The input terminal of the chopping circuit is used to connect to the Hall sensing circuit to receive the initial Hall sensing signal, the amplifying circuit is used to amplify the initial Hall sensing signal, and the chopping circuit is used to chop the amplified initial Hall sensing signal to output the amplified Hall sensing signal. Among them, the amplifying circuit includes at least one stage of operational amplifier, a first capacitor, and a second capacitor. The last operational amplifier in the at least one stage of operational amplifier is a driving-stage operational amplifier. One end of the first capacitor is connected to the first input terminal of the driving-stage operational amplifier, the other end of the first capacitor is connected to the first output terminal of the driving-stage operational amplifier, one end of the second capacitor is connected to the second input terminal of the driving-stage operational amplifier, and the other end of the second capacitor is connected to the second output terminal of the driving-stage operational amplifier. Based on the above method, by setting the first capacitor and the second capacitor on the driving-stage operational amplifier as Miller compensation capacitors, the bandwidth of the signal output by the driving-stage operational amplifier can be reduced, thereby playing a role of low-pass filtering. It can achieve the effect of low-pass filtering through the operation of the Miller compensation capacitor without additionally adding a low-pass filter, and reduce the volume of the signal processing circuit. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of an embodiment of the signal processing circuit of the present application; Figure 2 It is a schematic structural diagram of another embodiment of the signal processing circuit of the present application; Figure 3 It is a schematic structural diagram of yet another embodiment of the signal processing circuit of the present application; Figure 4 It is a schematic waveform diagram of an embodiment of the switching signal of the present application; Figure 5 It is a schematic structural diagram of an embodiment of the Hall detection device of the present application.

[0019] Reference numerals: 1, chopping circuit; 11, first chopper; 12, second chopper; 2, amplification circuit; 21, operational amplifier; 211, input-stage operational amplifier; 2111, first input-stage operational amplifier; 2112, second input-stage operational amplifier; 212, summing-stage operational amplifier; 213, driving-stage operational amplifier; 22, first capacitor; 23, second capacitor; 24, third capacitor; 25, first resistor; 26, second resistor; 27, third resistor; 28, fourth resistor; 30, Hall detection device; 31, Hall sensing circuit; 32, signal processing circuit. Detailed implementation manners

[0020] The following will further describe the present application in detail with reference to the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only partial embodiments of the present application rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0021] The mention of "embodiment" in this article means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "set", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0023] This application proposes a signal processing circuit. Refer to Figure 1 , Figure 1 which is a schematic structural diagram of an embodiment of the signal processing circuit of this application. As Figure 1 shown, the signal processing circuit includes a chopper circuit 1 and an amplifier circuit 2.

[0024] The input end of the chopper circuit 1 is used to connect to the Hall sensing circuit 31 to receive the Hall sensing initial signal. The amplifier circuit 2 is used to amplify the Hall sensing initial signal, and the chopper circuit 1 is used to perform chopping processing on the Hall sensing initial signal after amplification processing to output the Hall sensing amplified signal.

[0025] Among them, the amplifier circuit 2 includes at least one stage of operational amplifier 21, a first capacitor 22, and a second capacitor 23.

[0026] The last operational amplifier 21 in at least one stage of operational amplifier 21 is the driving stage operational amplifier 213.

[0027] One end of the first capacitor 22 is connected to the first input end of the driving stage operational amplifier 213, and the other end of the first capacitor 22 is connected to the first output end of the driving stage operational amplifier 213.

[0028] One end of the second capacitor 23 is connected to the second input end of the driving stage operational amplifier 213, and the other end of the second capacitor 23 is connected to the second output end of the driving stage operational amplifier 213.

[0029] Specifically, the received Hall sensing initial signal can be first subjected to the first chopping process by the chopper circuit 1, then the signal after the first chopping process can be amplified by the amplifier circuit 2, and then the signal after the amplification process can be subjected to the second chopping process by the chopper circuit 1 to obtain the Hall sensing amplified signal. This can not only amplify the Hall sensing amplified signal relative to the Hall sensing initial signal, but also make the frequency of the offset voltage signal in the Hall sensing amplified signal higher than the frequency of the offset voltage signal in the Hall sensing initial signal.

[0030] The amplification circuit 2 can achieve the above effect of amplifying the Hall sensing amplified signal relative to the Hall sensing initial signal through at least one stage of operational amplifier 21. A first capacitor 22 and a second capacitor 23 can be provided on the last operational amplifier 21 of the at least one stage of operational amplifier 21, that is, the driving stage operational amplifier 213, so as to use these two capacitors as Miller compensation capacitors, making the bandwidth of the signal output via the driving stage operational amplifier 213 narrower than that of the signal input to the driving stage operational amplifier 213. Thus, the offset voltage signal with increased frequency in the Hall sensing amplified signal described above is filtered out. Without the need to provide an analog filter with a low-pass filtering function subsequently, the signal processing circuit can have a low-pass filtering effect, removing the offset voltage signal generated by the Hall sensing circuit 31 that generates the Hall sensing initial signal or the amplification circuit 2 that amplifies the Hall sensing initial signal, thereby reducing the occupied area required for each device in the signal processing circuit, and further reducing the volume of the signal processing circuit.

[0031] Different from the prior art, in the technical solution of the present application, the signal processing circuit includes a chopping circuit and an amplification circuit. The input end of the chopping circuit is used to connect to the Hall sensing circuit to receive the Hall sensing initial signal. The amplification circuit is used to amplify the Hall sensing initial signal. The chopping circuit is used to chop the Hall sensing initial signal after amplification processing to output the Hall sensing amplified signal. Among them, the amplification circuit includes at least one stage of operational amplifier, a first capacitor, and a second capacitor. The last operational amplifier in the at least one stage of operational amplifier is the driving stage operational amplifier. One end of the first capacitor is connected to the first input end of the driving stage operational amplifier, and the other end of the first capacitor is connected to the first output end of the driving stage operational amplifier. One end of the second capacitor is connected to the second input end of the driving stage operational amplifier, and the other end of the second capacitor is connected to the second output end of the driving stage operational amplifier. Based on the above method, by setting the first capacitor and the second capacitor on the driving stage operational amplifier as Miller compensation capacitors, the bandwidth of the signal output by the driving stage operational amplifier can be reduced, thereby playing a low-pass filtering role, achieving the low-pass filtering effect through the operation of the Miller compensation capacitors without additionally adding a low-pass filter, and reducing the volume of the signal processing circuit.

[0032] In one embodiment, as Figure 1 shown, the signal processing circuit further includes a third capacitor 24.

[0033] The first output end and the second output end of the chopping circuit 1 jointly output the Hall sensing amplified signal. One end of the third capacitor 24 is connected to the first output end of the chopping circuit 1, and the other end of the third capacitor 24 is connected to the second output end of the chopping circuit 1. Or, See Figure 2 ,Figure 2 is a schematic structural diagram of another embodiment of the signal processing circuit of the present application. As Figure 2 shown, the first output terminal and the second output terminal of the amplifier circuit 2 jointly output the initially amplified Hall sensing signal. One end of the third capacitor 24 is connected to the first output terminal of the amplifier circuit 2, and the other end of the third capacitor 24 is connected to the second output terminal of the amplifier circuit 2.

[0034] Specifically, by setting the third capacitor 24 at the output terminal of the chopper circuit 1 or at the output terminal of the amplifier circuit 2, the duration of the high level conversion to the low level and the duration of the low level conversion to the high level in the Hall sensing amplified signal can be reduced, that is, the edge of the level change of the Hall sensing amplified signal becomes steeper, so as to reduce the output noise and the aliasing noise, thereby improving the signal processing effect.

[0035] In one embodiment, as Figure 1 or Figure 2 shown, at least one stage of operational amplifier 21 includes an input stage operational amplifier 211, a summing stage operational amplifier 212, and a driving stage operational amplifier 213 connected in sequence.

[0036] The input terminal of the input stage operational amplifier 211 is connected to the output terminal of the driving stage operational amplifier 213.

[0037] Specifically, the input terminal of the input stage operational amplifier 211 can be connected to the output terminal of the driving stage operational amplifier 213 through a corresponding feedback branch, so that the amplifier circuit 2 forms a current feedback type instrumentation amplifier structure. Compared with the traditional switched capacitor amplifier, since the input of the amplifier circuit 2 is high impedance, the influence on the dynamic response is small, and the response speed is improved.

[0038] Optionally, the positive input terminal of the input stage operational amplifier 211 is connected to the positive output terminal of the Hall sensing circuit 31, and the negative input terminal of the input stage operational amplifier 211 is connected to the negative output terminal of the Hall sensing circuit 31.

[0039] The positive input terminal of the input stage operational amplifier 211 is connected to the positive output terminal of the driving stage operational amplifier 213, and the negative input terminal of the input stage operational amplifier 211 is connected to the negative output terminal of the driving stage operational amplifier 213.

[0040] Specifically, as Figure 1 or Figure 2 shown, the positive input terminal of the input stage operational amplifier 211 is connected to the positive output terminal of the Hall sensing circuit 31 (for outputting Vsig1+) through a corresponding line, and is connected to the positive output terminal of the driving stage operational amplifier 213 (for outputting vfb-) through a corresponding line.

[0041] The negative input terminal of the input-stage operational amplifier 211 is connected to the negative output terminal of the Hall sensing circuit 31 (for outputting Vsig1-) through a corresponding line, and is also connected to the negative output terminal of the driver-stage operational amplifier 213 (for outputting vfb+) through a corresponding line.

[0042] Optionally, as Figure 1 or Figure 2 shown, the chopper circuit 1 includes a first chopper 11 and a second chopper 12, and at least one stage of operational amplifier 21 includes at least two input-stage operational amplifiers 211.

[0043] The input terminal of the first chopper 11 is used to connect to the Hall sensing circuit 31 to receive the Hall sensing initial signal. The output terminal of the first chopper 11 is respectively connected to the input terminals of the input-stage operational amplifiers 211 through corresponding switches. The output terminals of the input-stage operational amplifiers 211 are connected to the input terminal of the summing-stage operational amplifier 212. The output terminal of the summing-stage operational amplifier 212 is connected to the input terminal of the driver-stage operational amplifier 213. The input terminals of the input-stage operational amplifiers 211 are respectively connected to the output terminal of the driver-stage operational amplifier 213 through corresponding feedback branches. The output terminal of the driver-stage operational amplifier 213 is connected to the input terminal of the second chopper 12, and the output terminal of the second chopper 12 is used to output the Hall sensing amplified signal.

[0044] Specifically, the feedback branch can specifically be a switch or a branch with switch capabilities.

[0045] In one example: A part of the at least two input-stage operational amplifiers 211 can be conductively connected to the output terminal of the first chopper 11 and disconnected from the output terminal of the driver-stage operational amplifier 213, so as to use this part of the amplifiers as gain amplifiers.

[0046] At the same time, another part of the at least two input-stage operational amplifiers 211 is disconnected from the output terminal of the first chopper 11 and conductively connected to the output terminal of the driver-stage operational amplifier 213, so as to use this other part of the amplifiers as feedback amplifiers.

[0047] Based on the above method, in the signal processing circuit, through this part of the amplifiers, the summing-stage operational amplifier 212, and the driver-stage operational amplifier 213, the corresponding signal can be amplified and output, and through the driver-stage operational amplifier 213 and this other part of the amplifiers, the signal output by the driver-stage operational amplifier 213 can be fed back to the input terminal of the summing-stage operational amplifier 212.

[0048] In the first case, when there is one amplifier in one part and also one amplifier in the other part, the sum of the currents output by the two input-stage operational amplifiers 211 is zero, and the input-output relationship of the signal processing circuit can be obtained as follows: VOUT = (gm1 / gm2) * VIN * β Wherein, VOUT is the Hall sensing amplified signal, VIN is the Hall sensing initial signal, gm1 is the transconductance of the amplifier in one part (the ratio of the current to the voltage on the field effect transistor in the corresponding amplifier), gm2 is the transconductance of the amplifier in the other part, and β is the first proportionality coefficient.

[0049] In the second case, when there are N amplifiers in one part, the input terminals of each amplifier in the one part are respectively connected to the corresponding Hall sensing circuit 31, and there is one amplifier in the other part, the sum of the currents output by the two input-stage operational amplifiers 211 is zero, and the input-output relationship of the signal processing circuit can be obtained as follows: VOUT = (gm1 / gm2) * VIN * β * N Wherein, VOUT is the Hall sensing amplified signal, VIN is the Hall sensing initial signal, gm1 is the transconductance of the amplifier in one part, gm2 is the transconductance of the amplifier in the other part, β is the first proportionality coefficient, and N is the number of amplifiers in the one part.

[0050] Based on the above method, a signal processing circuit with a current feedback type instrumentation amplifier structure that can be compatible with any number of Hall sensing circuits 31 can be constructed, improving the application range and usage flexibility of the signal processing circuit.

[0051] Furthermore, on the premise of the embodiment in which the chopper circuit 1 includes a first chopper 11 and a second chopper 12, and at least one stage of operational amplifier 21 includes at least two input-stage operational amplifiers 211, as Figure 1 or Figure 2 shown, the number of at least two input-stage operational amplifiers 211 is greater than the number of Hall sensing circuits 31, and each Hall sensing circuit 31 is respectively connected to the corresponding input-stage operational amplifier 211 through the corresponding first chopper 11.

[0052] One input-stage operational amplifier 211 among the at least two input-stage operational amplifiers 211 serves as a feedback amplifier, and the input-stage operational amplifiers 211 other than the feedback amplifier among the at least two input-stage operational amplifiers 211 serve as gain amplifiers.

[0053] The switch between the input terminal of the gain amplifier and the corresponding first chopper 11 is turned on, and the switch between the input terminal of each gain amplifier and the output terminal of the drive-stage operational amplifier 213 is turned off.

[0054] The switch between the input terminal of the feedback amplifier and the output terminal of the driving-stage operational amplifier 213 is turned on, and the switch between the input terminal of the feedback amplifier and the corresponding first chopper 11 is turned off.

[0055] Specifically, in the first example, as Figure 1 or Figure 2 shown, the number of at least two input-stage operational amplifiers 211 is 2. One of the input-stage operational amplifiers 211 can be used as a gain amplifier, and the other input-stage operational amplifier 211 can be used as a feedback amplifier.

[0056] Refer to Figure 3 , Figure 3 which is a schematic structural diagram of another embodiment of the signal processing circuit of the present application. As Figure 3 shown, the number of at least two input-stage operational amplifiers 211 is 3. One of the input-stage operational amplifiers 211 can be used as a feedback amplifier, and the other two input-stage operational amplifiers 211 are respectively used as gain amplifiers. The input terminal of each gain amplifier receives the Hall sensing initial signal output by a different Hall sensing circuit 31. For example, refer to Figure 4 , Figure 4 which is a schematic waveform diagram of an embodiment of the switching signal of the present application. As Figure 4 shown, assuming that the high level can turn on the corresponding switch and the low level can turn off the corresponding switch, φ1, φ2, and φ3 are three signals that are not all high at the same time. At any moment, one amplifier can be used as a feedback amplifier and the other two amplifiers can be used as gain amplifiers. As Figure 3 shown, VSIG1 and VSIG 2 can refer to the Hall sensing initial signals (which can be the Hall sensing initial signals after the corresponding first chopping) respectively output by different Hall sensing circuits 31. VSIG1 can refer to the output signal of one Hall sensing circuit 31, such as Figure 1 or Figure 2 the output signal jointly formed by vsig1+ and vsig1- shown. VSIG2 can refer to the output signal of another Hall sensing circuit 31, such as the output signal jointly formed by vsig2+ (not shown in the figure) and vsig2- (not shown in the figure). VFB can refer to the output signal of the driving-stage operational amplifier 213, such as Figure 1 or Figure 2 the output signal jointly formed by vbf+ and vbf- shown.

[0057] As Figure 1 or Figure 2As shown, the positive input terminal of the input-stage operational amplifier 211 is connected to the positive output terminal of the Hall sensing circuit 31 (for outputting Vsig1+) through a corresponding line, and is connected to the positive output terminal of the Hall sensing circuit 31 (for outputting Vsig2+) through a corresponding line, and is connected to the positive output terminal of the drive-stage operational amplifier 213 (for outputting vfb-) through a corresponding line.

[0058] The negative input terminal of the input-stage operational amplifier 211 is connected to the negative output terminal of the Hall sensing circuit 31 (for outputting Vsig1-) through a corresponding line, and is connected to the negative output terminal of the Hall sensing circuit 31 (for outputting Vsig2-) through a corresponding line, and is connected to the negative output terminal of the drive-stage operational amplifier 213 (for outputting vfb+) through a corresponding line.

[0059] Based on the above method, the signal processing circuit can process the signals output by the corresponding Hall sensing circuit 31 at different time intervals respectively, so as to perform operations such as amplification and offset voltage filtering, obtain the corresponding Hall sensing amplified signals, and improve the reliability of the signal processing circuit.

[0060] Furthermore, within a preset period, every preset time interval, the feedback amplifier is updated to one of the at least two input-stage operational amplifiers 211 that has not served as the feedback amplifier within this preset period.

[0061] Specifically, within a preset period, every preset time interval: the feedback amplifier is updated to one of the at least two input-stage operational amplifiers 211 that has not served as the feedback amplifier within this preset period, and the gain amplifier connected to the corresponding Hall sensing circuit 31 is switched to connect to the Hall sensing circuit 31 that has not been connected within this preset period.

[0062] For example, first, taking the at least two input-stage operational amplifiers 211 as 2 for example, as Figure 1 or Figure 2 shown, the at least one-stage operational amplifier 21 may include a first input-stage operational amplifier 2111 and a second input-stage operational amplifier 2112.

[0063] It can be controlled in an alternating first time period and second time period. In the first time period, the first input-stage operational amplifier 2111 is the gain amplifier, while the second input-stage operational amplifier 2112 is the feedback amplifier. In the second time period, the first input-stage operational amplifier 2111 is the feedback amplifier, while the second input-stage operational amplifier 2112 is the gain amplifier.

[0064] Second, taking the at least two input-stage operational amplifiers 211 as 3 for example, as Figure 3As shown, at least one-stage operational amplifier 21 may include a first input-stage operational amplifier 2111, a second input-stage operational amplifier 2112, and a third input-stage operational amplifier 2113.

[0065] Under the control of the switch signals φ1, φ2, and φ3 as shown in Figure 4 shown, when the high level turns on the corresponding switch and the low level turns off the corresponding switch, then: In the first period, the second input-stage operational amplifier 2112 receives the first Hall sensing initial signal VSIG1 output by one Hall sensing circuit 31 to serve as the first gain amplifier, the third input-stage operational amplifier 2113 receives the second Hall sensing initial signal VSIG2 output by the other Hall sensing circuit 31 to serve as the second gain amplifier, and the first input-stage operational amplifier 2111 receives the signal output by the driving-stage operational amplifier 213 to achieve the transmission of the feedback signal to serve as the feedback amplifier.

[0066] In the second period, the first input-stage operational amplifier 2111 receives the first Hall sensing initial signal VSIG1 output by one Hall sensing circuit 31 to serve as the first gain amplifier, the second input-stage operational amplifier 2112 receives the second Hall sensing initial signal VSIG2 output by the other Hall sensing circuit 31 to serve as the second gain amplifier, and the third input-stage operational amplifier 2113 receives the signal output by the driving-stage operational amplifier 213 to achieve the transmission of the feedback signal to serve as the feedback amplifier.

[0067] In the third period, the third input-stage operational amplifier 2113 receives the first Hall sensing initial signal VSIG1 output by one Hall sensing circuit 31 to serve as the first gain amplifier, the first input-stage operational amplifier 2111 receives the second Hall sensing initial signal VSIG2 output by the other Hall sensing circuit 31 to serve as the second gain amplifier, and the second input-stage operational amplifier 2112 receives the signal output by the driving-stage operational amplifier 213 to achieve the transmission of the feedback signal to serve as the feedback amplifier.

[0068] Repeating the processes that occur in the above first period, second period, and third period in sequence can achieve the effect of continuously switching the working functions of the 3 input-stage operational amplifiers 211, such that in each period, thereby reducing the gain error caused by different offset voltage signals between amplifiers and improving the reliability of the signal processing circuit.

[0069] Regarding the principle of reducing the gain error as described above, it is as follows: Taking the case where there are 2 input-stage operational amplifiers 211 as an example, even if in practice these at least two input-stage operational amplifiers 211 are all operational amplifiers of the same model / specification, due to the existence of different offset voltage signals, the transconductances of these 2 input-stage operational amplifiers 211 are not equal, that is, gm1≠gm2, which easily causes a gain error of more than 2% or other percentages between these 2 input-stage operational amplifiers 211. By the above way of alternately using these 2 input-stage operational amplifiers 211 as a gain amplifier and a feedback amplifier, it can achieve the effect of averaging gm1 and gm1, and reduce the gain error.

[0070] Assume that there is an offset voltage △ in the transconductance, gm1=(1 + △)*gm2. If the above control method of alternately using the working functions is not carried out, then gm1 / gm2=(1 + △) / 1. If the above control method of alternately using the working functions is carried out, then in the first time period gm1 / gm2=(1 + △) / 1, and in the second time period gm1 / gm2=1 / (1 + △). Looking at the average of the two time periods comprehensively, gm1 / gm2 is [(1 + △) / 1 + 1 / (1 + △)] / 2 = 1 + △ 2 / 2, that is, the gain error is reduced.

[0071] Furthermore, on the premise of the above embodiment where the chopper circuit 1 includes a first chopper 11 and a second chopper 12, and at least one stage of operational amplifier 21 includes at least two input-stage operational amplifiers 211, as Figure 1 or Figure 2 shown, at least one stage of operational amplifier 21 includes a first input-stage operational amplifier 2111 and a second input-stage operational amplifier 2112.

[0072] The first input terminal of the first chopper 11 is used to connect the first output terminal of the Hall sensing circuit 31, and the second input terminal of the first chopper 11 is used to connect the second output terminal of the Hall sensing circuit 31.

[0073] The first output terminal of the first chopper 11 is connected to the first input terminal of the first input-stage operational amplifier 2111 through a corresponding switch, the second output terminal of the first chopper 11 is connected to the second input terminal of the first input-stage operational amplifier 2111 through a corresponding switch, the first output terminal of the first chopper 11 is connected to the first input terminal of the second input-stage operational amplifier 2112 through a corresponding switch, and the second output terminal of the first chopper 11 is connected to the second input terminal of the second input-stage operational amplifier 2112 through a corresponding switch.

[0074] The first input terminal of the summing stage operational amplifier 212 is respectively connected to the first output terminal of the first input stage operational amplifier 2111 and the first output terminal of the second input stage operational amplifier 2112. The second input terminal of the summing stage operational amplifier 212 is respectively connected to the second output terminal of the first input stage operational amplifier 2111 and the second output terminal of the second input stage operational amplifier 2112.

[0075] The first input terminal of the driving stage operational amplifier 213 is connected to the first output terminal of the summing stage operational amplifier 212, and the second input terminal of the driving stage operational amplifier 213 is connected to the second output terminal of the summing stage operational amplifier 212.

[0076] The first input terminal of the second chopper 12 is connected to the first output terminal of the driving stage operational amplifier 213, the second input terminal of the second chopper 12 is connected to the second output terminal of the driving stage operational amplifier 213, and the first output terminal and the second output terminal of the second chopper 12 are used to commonly output the Hall sensing amplified signal.

[0077] The first input terminal of the second chopper 12 is connected to the second input terminal of the first input stage operational amplifier 2111 through the first feedback branch, the second input terminal of the second chopper 12 is connected to the first input terminal of the first input stage operational amplifier 2111 through the second feedback branch, the first input terminal of the second chopper 12 is connected to the second input terminal of the second input stage operational amplifier 2112 through the third feedback branch, and the second input terminal of the second chopper 12 is connected to the first input terminal of the second input stage operational amplifier 2112 through the fourth feedback branch.

[0078] Specifically, in the first input stage operational amplifier 2111, the first input terminal is the positive input terminal, the second input terminal is the negative input terminal, the first output terminal is the negative output terminal, and the second output terminal is the positive output terminal. In the second input stage operational amplifier 2112, the first input terminal is the positive input terminal, the second input terminal is the negative input terminal, the first output terminal is the negative output terminal, and the second output terminal is the positive output terminal.

[0079] In the summing stage operational amplifier 212, the first input terminal is the positive input terminal, the second input terminal is the negative input terminal, the first output terminal is the positive output terminal, and the second output terminal is the negative output terminal.

[0080] In the driving stage operational amplifier 213, the first input terminal is the positive input terminal, the second input terminal is the negative input terminal, the first output terminal is the negative output terminal, and the second output terminal is the positive output terminal.

[0081] Furthermore, as Figure 1 or Figure 2 shown, the signal processing circuit further includes a first resistor 25, a second resistor 26, a third resistor 27, and a fourth resistor 28.

[0082] One end of the first resistor 25 is connected to the first input terminal of the second chopper 12, and one end of the second resistor 26 is connected to the second input terminal of the second chopper 12. One end of the third resistor 27 is connected to the other end of the first resistor 25, and the other end of the third resistor 27 and one end of the fourth resistor 28 are respectively connected to a preset reference voltage, and the other end of the fourth resistor 28 is connected to the other end of the second resistor 26.

[0083] The other end of the first resistor 25 is connected to the second input terminal of the first input-stage operational amplifier 2111 through a first feedback branch.

[0084] The other end of the first resistor 25 is connected to the second input terminal of the second input-stage operational amplifier 2112 through a second feedback branch.

[0085] The other end of the second resistor 26 is connected to the first input terminal of the first input-stage operational amplifier 2111 through a third feedback branch.

[0086] The other end of the second resistor 26 is connected to the first input terminal of the second input-stage operational amplifier 2112 through a fourth feedback branch.

[0087] Specifically, the resistance values of the first resistor 25 and the second resistor 26 may be equal, and / or the resistance values of the third resistor 27 and the fourth resistor 28 may be equal.

[0088] In one example, as Figure 1 or Figure 2 shown, the preset reference voltage may refer to VREF.

[0089] The other end of the first resistor 25 outputs vfb+, and the other end of the second resistor 26 outputs vfb-.

[0090] vfb+ and vfb- together form the output signal VFB of the driving-stage operational amplifier 213 described above, including a common-mode signal and a differential-mode signal, and the calculation formula is as follows:

[0091]

[0092]

[0093] Among them, VREF is the preset reference voltage, R1 is the resistance value of the first resistor 25, R2 is the resistance value of the second resistor 26, γ is the second proportionality coefficient, voutp is the voltage signal output from one output terminal of the driving-stage operational amplifier 213, voutn is the voltage signal output from the other output terminal of the driving-stage operational amplifier 213, VFB1 is the common-mode signal, and VFB2 is the differential-mode signal.

[0094] Based on the above method, a suitable adjustable VFB can be input to the corresponding input-stage operational amplifier 211 through the voltage-dividing circuit constructed by the first resistor 25, the second resistor 26, the third resistor 27, and the fourth resistor 28 for use as a feedback signal, realizing the differential transmission of the feedback voltage and constructing a signal processing circuit of a current-feedback instrumentation amplifier structure.

[0095] The present application also proposes a Hall detection device. Refer to Figure 5 , Figure 5 which is a schematic structural diagram of an embodiment of the Hall detection device of the present application. As shown in Figure 5 , the Hall detection device 30 includes a Hall sensing circuit 31 and a signal processing circuit 32, and the signal processing circuit 32 is connected to the Hall sensing circuit 31.

[0096] The signal processing circuit 32 may specifically be the signal processing circuit described in any of the foregoing embodiments, which will not be elaborated herein.

[0097] Different from the prior art, in the technical solution of the present application, the signal processing circuit includes a chopper circuit and an amplification circuit. The input end of the chopper circuit is used to connect to the Hall sensing circuit to receive the initial Hall sensing signal. The amplification circuit is used to amplify the initial Hall sensing signal. The chopper circuit is used to perform chopping processing on the amplified initial Hall sensing signal to output an amplified Hall sensing signal. Among them, the amplification circuit includes at least one stage of operational amplifier, a first capacitor, and a second capacitor. The last operational amplifier in the at least one stage of operational amplifier is a driving-stage operational amplifier. One end of the first capacitor is connected to the first input end of the driving-stage operational amplifier, and the other end of the first capacitor is connected to the first output end of the driving-stage operational amplifier. One end of the second capacitor is connected to the second input end of the driving-stage operational amplifier, and the other end of the second capacitor is connected to the second output end of the driving-stage operational amplifier. Based on the above method, by setting the first capacitor and the second capacitor on the driving-stage operational amplifier as Miller compensation capacitors, the bandwidth of the signal output by the driving-stage operational amplifier can be reduced, thereby playing a role of low-pass filtering. It can achieve the effect of low-pass filtering through the operation of the Miller compensation capacitors without additionally adding a low-pass filter, reducing the volume of the signal processing circuit.

[0098] In the description of the present application, the descriptions with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0099] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0100] Any process or method description shown in a flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0101] Logic and / or steps represented in the flowchart or otherwise described herein can, for example, be considered as a definitional sequence of executable instructions for implementing logical functions and can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device (which can be a personal computer, a server, a network device, or other system that can fetch instructions from the instruction execution system, apparatus, or device and execute the instructions). For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium can even be paper or other suitable medium on which the program can be printed, as the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpretation, or otherwise processing as appropriate, and then storing it in a computer memory.

[0102] The above description is only for the implementation modes of this application and does not limit the patent scope of this application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of this application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of this application.

Claims

1. A signal processing circuit, characterized in that: include: Chopper circuit; an amplifier circuit, wherein the input end of the chopper circuit is used to connect to the Hall sensor circuit to receive the Hall sensor initial signal, the amplifier circuit is used to amplify the Hall sensor initial signal, and the chopper circuit is used to chop the Hall sensor initial signal after the amplification process to output the Hall sensor amplified signal; Wherein, the amplifying circuit comprises: At least one stage of operational amplifiers, wherein the last operational amplifier in the at least one stage of operational amplifiers is a driver stage operational amplifier; A first capacitor, one end of the first capacitor is connected to the first input end of the driving stage operational amplifier, and the other end of the first capacitor is connected to the first output end of the driving stage operational amplifier; A second capacitor, one end of the second capacitor is connected to the second input end of the driving stage operational amplifier, and the other end of the second capacitor is connected to the second output end of the driving stage operational amplifier.

2. The signal processing circuit according to claim 1, characterized in that: The signal processing circuit further includes a third capacitor; The first output terminal and the second output terminal of the chopper circuit jointly output the Hall sensor amplified signal, one end of the third capacitor is connected to the first output terminal of the chopper circuit, and the other end of the third capacitor is connected to the second output terminal of the chopper circuit. or, The first output terminal and the second output terminal of the amplifier circuit jointly output the Hall sensor initial signal after the amplification process, one end of the third capacitor is connected to the first output terminal of the amplifier circuit, and the other end of the third capacitor is connected to the second output terminal of the amplifier circuit.

3. The signal processing circuit according to claim 1 or 2, characterized in that: The at least one stage operational amplifier comprises an input stage operational amplifier, a summing stage operational amplifier and the driving stage operational amplifier connected in sequence; The input end of the input stage operational amplifier is connected to the output end of the driving stage operational amplifier.

4. The signal processing circuit according to claim 3, characterized in that: The positive input terminal of the input stage operational amplifier is connected to the positive output terminal of the Hall sensor circuit, and the negative input terminal of the input stage operational amplifier is connected to the negative output terminal of the Hall sensor circuit; The positive input terminal of the input stage operational amplifier is connected to the positive output terminal of the driving stage operational amplifier, and the negative input terminal of the input stage operational amplifier is connected to the negative output terminal of the driving stage operational amplifier.

5. The signal processing circuit according to claim 3, characterized in that: The chopper circuit includes a first chopper and a second chopper, and the at least one stage operational amplifier includes at least two input stage operational amplifiers; The input end of the first chopper is used to connect to the Hall sensing circuit to receive the Hall sensing initial signal. The output end of the first chopper is connected to the input end of each input stage operational amplifier through a corresponding switch. The output end of the input stage operational amplifier is connected to the input end of the summing stage operational amplifier. The output end of the summing stage operational amplifier is connected to the input end of the driving stage operational amplifier. The input end of each input stage operational amplifier is connected to the output end of the driving stage operational amplifier through a corresponding feedback branch. The output end of the driving stage operational amplifier is connected to the input end of the second chopper. The output end of the second chopper is used to output the Hall sensing amplified signal.

6. The signal processing circuit according to claim 5, characterized in that: The number of the at least two input-stage operational amplifiers is greater than the number of the Hall sensor circuits, and each of the Hall sensor circuits is connected to the corresponding input-stage operational amplifier via the corresponding first chopper; One of the at least two input-stage operational amplifiers is used as a feedback amplifier, and the input-stage operational amplifiers other than the feedback amplifier of the at least two input-stage operational amplifiers are used as gain amplifiers; The switch between the input end of the gain amplifier and the corresponding first chopper is turned on, and the switch between the input end of each gain amplifier and the output end of the driving stage operational amplifier is turned off; The switch between the input end of the feedback amplifier and the output end of the driving stage operational amplifier is turned on, and the switch between the input end of the feedback amplifier and the corresponding first chopper is turned off.

7. The signal processing circuit according to claim 6, characterized in that: In a preset cycle, at intervals of a preset time, the feedback amplifier is updated to an input-stage operational amplifier of the at least two input-stage operational amplifiers that does not serve as the feedback amplifier in the preset cycle.

8. The signal processing circuit according to claim 7, characterized in that: Within a preset period, at each interval of a preset duration: the feedback amplifier is updated to an input-stage operational amplifier among the at least two input-stage operational amplifiers that has not served as the feedback amplifier within the preset period, and the gain amplifier connected to the corresponding Hall sensor circuit is switched to connect to the Hall sensor circuit that has not been connected within the preset period.

9. The signal processing circuit according to any one of claims 5 to 8, characterized in that: The at least one stage operational amplifier comprises a first input stage operational amplifier and a second input stage operational amplifier; The first input end of the first chopper is used to connect to the first output end of the Hall sensor circuit, and the second input end of the first chopper is used to connect to the second output end of the Hall sensor circuit; The first output end of the first chopper is connected to the first input end of the first input stage operational amplifier through a corresponding switch, the second output end of the first chopper is connected to the second input end of the first input stage operational amplifier through a corresponding switch, the first output end of the first chopper is connected to the first input end of the second input stage operational amplifier through a corresponding switch, and the second output end of the first chopper is connected to the second input end of the second input stage operational amplifier through a corresponding switch; The first input end of the summing stage operational amplifier is respectively connected to the first output end of the first input stage operational amplifier and the first output end of the second input stage operational amplifier, and the second input end of the summing stage operational amplifier is respectively connected to the second output end of the first input stage operational amplifier and the second output end of the second input stage operational amplifier; The first input end of the driver stage operational amplifier is connected to the first output end of the summing stage operational amplifier, and the second input end of the driver stage operational amplifier is connected to the second output end of the summing stage operational amplifier; The first input end of the second chopper is connected to the first output end of the driving stage operational amplifier, the second input end of the second chopper is connected to the second output end of the driving stage operational amplifier, and the first output end of the second chopper and the second output end of the second chopper are used to jointly output the Hall sensor amplified signal; The first input end of the second chopper is connected to the second input end of the first input-stage operational amplifier through a first feedback branch, the second input end of the second chopper is connected to the first input end of the first input-stage operational amplifier through a second feedback branch, the first input end of the second chopper is connected to the second input end of the second input-stage operational amplifier through a third feedback branch, and the second input end of the second chopper is connected to the first input end of the second input-stage operational amplifier through a fourth feedback branch.

10. The signal processing circuit according to claim 9, characterized in that: The signal processing circuit further includes a first resistor, a second resistor, a third resistor and a fourth resistor; A first input end of the second chopper is connected to one end of the first resistor, a second input end of the second chopper is connected to one end of the second resistor, one end of the third resistor is connected to the other end of the first resistor, the other end of the third resistor and one end of the fourth resistor are respectively connected to a preset reference voltage, and the other end of the fourth resistor is connected to the other end of the second resistor; The other end of the first resistor is connected to the second input end of the first input stage operational amplifier through the first feedback branch; The other end of the first resistor is connected to the second input end of the second input stage operational amplifier through the second feedback branch; The other end of the second resistor is connected to the first input end of the first input stage operational amplifier through the third feedback branch; The other end of the second resistor is connected to the first input end of the second input stage operational amplifier through the fourth feedback branch.

11. A Hall detection device, characterized in that: include: Hall sensor circuit; The signal processing circuit according to any one of claims 1 to 10, wherein the signal processing circuit is connected to the Hall sensor circuit.

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