CN116466123A - High-precision high-current acquisition circuit and method supporting multi-gear switching - Google Patents
High-precision high-current acquisition circuit and method supporting multi-gear switching Download PDFInfo
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Abstract
The invention discloses a high-precision heavy current acquisition circuit and a method for supporting multi-gear switching, wherein the high-precision heavy current acquisition circuit comprises a plurality of current sampling circuits with different gears, all the current sampling circuits are connected in parallel, a power relay is connected to a loop where each current sampling circuit is located, parallel output ends of all the current sampling circuits are connected with an analog switch selection circuit through a differential operational amplifier circuit, the analog switch selection circuit amplifies sampling signals in different proportions by closing different analog switches, and the analog switch selection circuit is connected with a signal sampling port of an MCU through a later stage amplifying circuit; the invention has the advantages that: the multi-range and multi-gear easy switching is realized, so that the high-precision measurement and control in the whole range are realized.
Description
Technical Field
The invention relates to the field of electronic equipment for measurement and test, in particular to a high-precision high-current acquisition circuit and method supporting multi-gear switching.
Background
In the direct current collection scheme of large current output, a large-range Hall sensor or a precise resistor is generally adopted for realizing.
A mode of a large-range Hall sensor, such as Chinese patent publication No. CN107525963A, discloses a Hall-based current sampling method, and has the advantages of self-electrified isolation of the Hall sensor and simple circuit design. However, the defects are also obvious, that is, the wide-range hall sensor is huge, the price is not very good, the precision is poor in small current, that is, the linearity is not good enough, meanwhile, the wide-range hall sensor also has the problem of sampling bias, that is, when the hall sensor passes through large current, the magnetic bias phenomenon can occur in the hall sensor, so that the sampling precision can generate obvious bias, the hall sensor can be restored to the initial state only after the equipment is powered off and reset, the phenomenon of the hall sensor has little influence on most application occasions, but has great influence on the electronic equipment for measurement and test, and the electronic equipment for measurement and test often needs extremely high measurement and control precision.
A precise resistor mode, such as China patent publication No. CN217007520U, discloses a precise current sensor circuit based on a sampling resistor, which has the advantages of small volume, easy placement, relatively low price compared with a Hall sensor, and no magnetic bias phenomenon. However, the precision resistor has obvious defects in the application of high current. Because the current is larger, the loss is larger and the heating is serious compared with a Hall sensor, thereby causing serious temperature drift. And the sampling mode of the precision resistor is not isolated, an isolated sampling circuit is needed to be additionally arranged, and the circuit design is more complex.
Because the use environment and the use working conditions of the electronic equipment for measurement and test are complex and changeable, the equipment with large current output can be used in the occasion with small current in many cases, and the requirements of users on precision are very high. According to the above, it is difficult to ensure the measurement and control accuracy of the dc power supply with large current output in the whole range, especially the accuracy in the case of small current output, regardless of the scheme of the wide range hall sensor or the precision resistor.
Disclosure of Invention
The invention aims to solve the technical problem of providing a direct current acquisition scheme with high current output so as to ensure the measurement and control precision of a direct current power supply with high current output in a full-range.
The invention solves the technical problems by the following technical means: the utility model provides a support high accuracy heavy current acquisition circuit that multispeed switches, includes the current sampling circuit of a plurality of different gears, all current sampling circuit connects in parallel and all connects power relay on the circuit that every current sampling circuit is located, and all current sampling circuit's parallel output passes through differential operational amplifier circuit and analog switch selection circuit to be connected, analog switch selection circuit carries out the amplification of different proportion to the sampling signal through closing different analog switches, and analog switch selection circuit passes through the signal sampling port connection of rear stage amplifying circuit and MCU.
The beneficial effects are that: the invention selects the number of parallel current sampling circuits by adding the power relay and the analog switch selection circuit, so that the measurable output current range can be flexibly adjusted, thereby realizing the switching of different gears, the large current is the parallel output of the small current sampling circuits, the smaller the number of parallel current sampling circuit groups is, the smaller the output current is, therefore, the small-range output is parallel connected to form the large-range output, a plurality of defects of the traditional large-range Hall sensor are avoided, the problems that the linearity of the large-range Hall sensor is poor and the precision is influenced when the small current is, the easy switching of multiple ranges and multiple gears is realized, the high-precision measurement and control in the full range are realized, especially the measurement and control precision under the small current or even the extremely small current are greatly improved, and the full range adaptability of the large-range power supply is greatly improved.
Further, each current sampling circuit has the same structure, each current sampling circuit comprises a plurality of parallel Hall elements, one end of each of the plurality of parallel Hall elements is connected with a power supply cathode, the other end of each of the plurality of parallel Hall elements is connected with one end of a load through a power relay, and the other end of the load is connected with a power supply anode.
Further, the current sampling circuit is in a high gear, the current sampling circuit in the high gear comprises 5 hall elements H1 to H5 (taking a direct current power supply output by 500A as an example, and taking a direct current power supply output by 500A as an example, the current sampling circuit in a middle gear, the current sampling circuit in a low gear, the current sampling circuit in an extremely low gear and the like as well as the circuit in the extremely low gear) which are connected in parallel, the hall elements H1 to H5 are connected in parallel, one end of the hall elements H1 to H5 connected in parallel is connected with a power supply negative electrode, and the other end of the hall elements H1 to H5 connected in parallel is connected with one end of a load through a power relay RealyH, and the other end of the load is connected with a power supply positive electrode.
Still further, the current sampling circuit is of a middle gear, the current sampling circuit of the middle gear comprises 3 hall elements M1 to M3 of 50A, the hall elements M1 to M3 are connected in parallel, one end of each of the hall elements M1 to M3 connected in parallel is connected with a power supply cathode, the other end of each of the hall elements M1 to M3 connected in parallel is connected with one end of a load through a power relay RealyM, and the other end of the load is connected with a power supply anode.
Still further, the current sampling circuit is low gear, and the current sampling circuit of low gear includes 2 hall element L1 and hall element L2 of 50A, and hall element L1 and hall element L2 parallel connection, the one end after hall element L1 and hall element L2 parallel connection connects the power negative pole, and the other end after hall element L1 and hall element L2 parallel connection is connected with the one end of load through a power relay realyL, and the other end of load is connected with the power positive pole.
Further, the current sampling circuit is in an extremely low gear, the extremely low gear current sampling circuit comprises a 10A Hall element SL, one end of the Hall element SL is connected with a power supply cathode, the other end of the Hall element SL is connected with one end of a load through a power relay RealySL, and the other end of the load is connected with a power supply anode.
Furthermore, the input end of the differential operational amplifier circuit is connected with the other ends of the plurality of parallel Hall elements, and the output end of the differential operational amplifier circuit is connected with the analog switch selection circuit.
Still further, the analog switch selection circuit includes a switch SWH, a switch SWM, a switch SWL, a switch SWSL, a resistor RH, a resistor RM, a resistor RL, and a resistor RSL, the input end of the differential operational amplifier circuit is connected with the other ends of the plurality of parallel hall elements, one end of the switch SWH, one end of the switch SWM, one end of the switch SWL, and one end of the switch SWSL are connected with the output end of the differential operational amplifier circuit, the other end of the switch SWH, the other end of the switch SWM, the other end of the switch SWL, and the other end of the switch SWSL are respectively connected with one end of the resistor RH, one end of the resistor RM, one end of the resistor RL, and one end of the resistor RSL, and the other end of the resistor RH, the other end of the resistor RM, and the other end of the resistor RSL are connected together as the parallel output end of the analog switch selection circuit.
Still further, the later stage amplifying circuit includes operational amplifier A21, operational amplifier A22, resistance R5 to resistance R8 and resistance RX, operational amplifier A21's homophase end is through resistance R5 ground connection, the one end of resistance RX and operational amplifier A21's inverting terminal all are connected with analog switch selection circuit's parallelly connected output, the other end of resistance RX is connected with operational amplifier A21's output and resistance R6's one end, resistance R6's the other end, resistance R7's one end and operational amplifier A22's inverting terminal are connected, operational amplifier A22's homophase end passes through resistance R8 ground connection, resistance R7's the other end and operational amplifier A22's output are connected and are connected with MCU's signal sampling port.
The invention also provides a high-precision large-current acquisition method supporting multi-gear switching, which is applied to the high-precision large-current acquisition circuit supporting multi-gear switching, when a user selects a gear, a corresponding number of power relays are attracted, current flows through Hall elements connected with the attracted power relays, and output current sampling signals are all connected in parallel and output to a differential operational amplifier circuit for differential amplification, the differential operational amplifier circuit outputs the signals to an analog switch selection circuit, the analog switch selection circuit closes different analog switches according to the selected gear to amplify the sampling signals in different proportions, so that the voltage values of the sampling signals finally reaching an MCU under different ranges are all the highest voltage values which can be sampled by the MCU.
The invention has the advantages that:
(1) The invention selects the number of parallel current sampling circuits by adding the power relay and the analog switch selection circuit, so that the measurable output current range can be flexibly adjusted, thereby realizing the switching of different gears, the large current is the parallel output of the small current sampling circuits, the smaller the number of parallel current sampling circuit groups is, the smaller the output current is, therefore, the small-range output is parallel connected to form the large-range output, a plurality of defects of the traditional large-range Hall sensor are avoided, the problems that the linearity of the large-range Hall sensor is poor and the precision is influenced when the small current is, the easy switching of multiple ranges and multiple gears is realized, the high-precision measurement and control in the full range are realized, especially the measurement and control precision under the small current or even the extremely small current are greatly improved, and the full range adaptability of the large-range power supply is greatly improved.
(2) The invention adds the power relay and the analog switch selection circuit, thereby flexibly selecting the number of the Hall elements connected in parallel in the sampling circuit and the amplification factor of the operational amplifier end, leading the measurable output current range to be flexibly adjustable, and realizing the flexible switching of different sampling gears.
(3) The invention utilizes the characteristic that the current can realize automatic addition after being connected in parallel, and adopts a plurality of small-range current type Hall elements to replace a large-range Hall element. Because the volume of the small-range current type Hall element is far smaller than that of the large-range Hall element, and the price of the small-range current type Hall element is far lower than that of the large-range Hall element, the arrangement of the power space can be more conveniently carried out, and the cost can be better reduced. Meanwhile, the sampling bias problem of the small-range current type Hall element is very little, so that the sampling bias problem brought by the Hall sensor can be greatly reduced.
(4) According to the invention, according to different measuring ranges selected by a user, different numbers of power relays can be switched, so that the sum of currents actually flowing through the relays is just equal to the upper limit current value of the measuring range selected by the user, thus the interference signal acquired by a source (a Hall sensor) can be reduced to the greatest extent, the sampling signal is more stable, and the sampling precision is higher. Meanwhile, according to different user selection ranges, an analog switch selection circuit is added on a sampling signal processing branch, and different amplification ratios of sampling signals are realized by selecting the opening and closing of different analog switches, so that the MCU port voltage corresponding to the maximum current under different ranges is always the highest voltage value which can be sampled.
(5) The invention sets an extremely low range gear, adopts a smaller Hall element, so that the direct current source with nominal rated current of 500A can still maintain extremely high sampling and control precision even under the condition of extremely small current (1A or even smaller) output.
Drawings
FIG. 1 is a schematic diagram of a main power portion of a high-precision high-current acquisition circuit supporting multi-gear switching according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a control part of a sampling signal processor analog switch of a high-precision high-current acquisition circuit supporting multi-gear switching according to an embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in FIG. 1, the high-precision large-current acquisition circuit supporting multi-gear switching comprises a plurality of current sampling circuits with different gears, all the current sampling circuits are connected in parallel, a power relay is connected to a loop where each current sampling circuit is located, parallel output ends of all the current sampling circuits are connected with an analog switch selection circuit through a differential operational amplifier circuit, the analog switch selection circuit amplifies sampling signals in different proportions by closing different analog switches, and the analog switch selection circuit is connected with a signal sampling port of an MCU through a later-stage amplifying circuit.
With continued reference to fig. 1, each current sampling circuit has the same structure, each current sampling circuit includes a plurality of parallel hall elements, the high-precision large-current collecting circuit supporting multi-gear switching further includes a filter circuit, the filter circuit includes an inductor L and a capacitor C, the filter circuit filters output voltage and current waveforms to realize smaller ripple output, one end of the inductor L is connected with a positive electrode of a power supply, a negative electrode of the capacitor C is connected with one end of a plurality of parallel hall elements of each current sampling circuit in parallel and is connected with a negative electrode of the power supply in parallel, the other ends of a plurality of parallel hall elements are connected with one end of a LOAD through a power relay, and the other ends of the inductor L and the positive electrode of the capacitor C are connected with the other end of the LOAD. The Hall elements of the invention are all Hall sensors.
With continued reference to fig. 1, the current sampling circuit is in a high gear, the current sampling circuit in the high gear includes 5 hall elements H1 to H5 (in this case, a direct current power source output by 500A is taken as an example, and circuits such as a current sampling circuit in a middle gear, a current sampling circuit in a low gear, and a current sampling circuit in an extremely low gear are also taken as examples of a direct current power source output by 500A), the hall elements H1 to H5 are connected in parallel, one ends of the hall elements H1 to H5 after being connected in parallel are connected with a negative electrode of the power supply, the other ends of the hall elements H1 to H5 after being connected in parallel are connected with one end of the load through a power relay RealyH, and the other ends of the load are connected with a positive electrode of the power supply.
With continued reference to fig. 1, the current sampling circuit is in a middle gear, the current sampling circuit in the middle gear comprises 3 hall elements M1 to M3 of 50A, the hall elements M1 to M3 are connected in parallel, one end of each of the hall elements M1 to M3 connected in parallel is connected with a power supply negative electrode, the other end of each of the hall elements M1 to M3 connected in parallel is connected with one end of a load through a power relay RealyM, and the other end of the load is connected with a power supply positive electrode.
With continued reference to fig. 1, the current sampling circuit is in a low gear, the current sampling circuit in the low gear comprises 2 hall elements L1 and L2 of 50A, the hall elements L1 and L2 are connected in parallel, one end of the hall elements L1 and L2 connected in parallel is connected with a power supply cathode, the other end of the hall elements L1 and L2 connected in parallel is connected with one end of a load through a power relay RealyL, and the other end of the load is connected with a power supply anode.
With continued reference to fig. 1, the current sampling circuit is in an extremely low gear, the extremely low gear current sampling circuit comprises a hall element SL of 10A, one end of the hall element SL is connected with a power supply cathode, the other end of the hall element SL is connected with one end of a load through a power relay RealySL, and the other end of the load is connected with a power supply anode.
Referring to fig. 2, the differential operational amplifier circuit includes a resistor Rs, a resistor R1 to a resistor R4, and an operational amplifier A1, wherein one end of the resistor Rs and one end of the resistor R1 are connected with the other ends of the plurality of parallel hall elements, the other end of the resistor Rs is connected with one end of the resistor R2 and grounded, the other end of the resistor R2, one end of the resistor R4, and the same-phase end of the operational amplifier A1 are connected, the other end of the resistor R4 is grounded, the other end of the resistor R1, one end of the resistor R3, and the opposite-phase end of the operational amplifier A1 are connected, and the other end of the resistor R3 is connected with the output end of the operational amplifier A1.
With continued reference to fig. 2, the analog switch selection circuit includes a switch SWH, a switch SWM, a switch SWL, a switch SWSL, a resistor RH, a resistor RM, a resistor RL, and a resistor RSL, where one end of the switch SWH, one end of the switch SWM, one end of the switch SWL, and one end of the switch SWSL are connected and connected to the output end of the op-amp A1, the other end of the switch SWH, the other end of the switch SWM, the other end of the switch SWL, and the other end of the switch SWSL are respectively connected to one end of the resistor RH, one end of the resistor RM, one end of the resistor RL, and one end of the resistor RSL, and the other end of the resistor RH, the other end of the resistor RM, the other end of the resistor RL, and the other end of the resistor RSL are connected together to be used as parallel output ends of the analog switch selection circuit.
With continued reference to fig. 2, the post-stage amplifying circuit includes an operational amplifier a21, an operational amplifier a22, a resistor R5 to a resistor R8, and a resistor RX, where the in-phase end of the operational amplifier a21 is grounded through the resistor R5, one end of the resistor RX and the inverting end of the operational amplifier a21 are connected with the parallel output end of the analog switch selecting circuit, the other end of the resistor RX is connected with the output end of the operational amplifier a21 and one end of the resistor R6, the other end of the resistor R6, one end of the resistor R7 and the inverting end of the operational amplifier a22 are connected, the in-phase end of the operational amplifier a22 is grounded through the resistor R8, and the other end of the resistor R7 and the output end of the operational amplifier a22 are connected and connected with the signal sampling port of the MCU.
The invention also provides a high-precision high-current acquisition method supporting multi-gear switching, which is applied to the circuit, and comprises the following specific implementation steps:
(a) Since the current is outputted with large current, the current is first required to be stepped, and the current can be divided into 4 steps of high, medium, low and extremely low by taking a direct current power supply outputted with 500A as an example, and the range correspondence is as follows:
high range H: 0-500A;
mid-range M: 0-250A;
low range L: 0-100A;
very low range SL:0 to 10A.
(b) As described above, the wide-range hall sensor has a plurality of disadvantages, so 10 small-range hall sensors 50A and 1 small-range hall sensor 10A are selected to replace the 500A wide-range hall sensor;
(c) After determining the current step and the small-range hall sensor, the hall element SL in fig. 1 is the small-range hall sensor of 10A; the Hall elements L1 … … Ln are 2 small-range Hall sensors of 50A; the Hall elements M1 … … Mn are 3 small-range Hall sensors of 50A; the Hall elements H1 … … Hn are 5 small-range Hall sensors of 50A;
(d) When a user selects a high range gear, the power relay RelayL, relayM, relayH needs to be attracted, the relay sl is disconnected, current flows through hall elements connected with the power relays, then current sampling signals output by all the hall elements are connected in parallel, namely Isense_H2 … … Isense_L in FIG. 2, and since the currents can be automatically added after being connected in parallel, io_sense in FIG. 2 is the sum of Isense_H2 … … Isense_L, namely a total output current sampling signal, and voltage signals Us are formed at two ends of Rs through a sampling resistor Rs;
(e) And Us are amplified by the differential operational amplifier circuit, so that the analog switch selection circuit is reached, and the sampling signals Us can be amplified in different proportions by closing different analog switches, so that the voltage value of the sampling signals finally reaching the MCU is as close as possible to the highest voltage value which can be sampled by the MCU, and the sampling precision of the MCU can be exerted more thoroughly. Because the Us values obtained are different when the user selects different range gears and outputs the maximum current in that gear, in order to enable the voltage value of the sampling signal reaching the MCU to be close to the highest voltage value that the MCU can sample when full current in all gears is output, analog switch switching is added here.
(f) Similarly, when the user selects the mid-range gear, the power relay RelayL, relayM needs to be closed, relayH, relaySL is opened, and the analog switch SWM is closed, so that the amplification ratio is RX/RM;
(g) Similarly, when the user selects a low range gear, the power relay Relay L needs to be attracted, relayH, relayM, relaySL is opened, the analog switch SWL is closed, and the amplification ratio is RX/RL;
(h) Similarly, when the user selects the very low range gear, the power relay Relay SL needs to be closed, relayH, relayM, relayL is opened, and the analog switch SWSL is closed, and the amplification ratio is RX/RSL.
The working principle of the invention is as follows:
the characteristic that the automatic addition can be realized after the parallel connection of the currents is utilized, and a plurality of small-range current type Hall sensors are adopted to replace a large-range Hall sensor. Because the volume of the small-range current type Hall sensor is far smaller than that of the large-range Hall sensor, and the price of the small-range current type Hall sensor is far lower than that of the large-range Hall sensor, the arrangement of the power space can be more conveniently carried out, and the cost can be better reduced. Meanwhile, the sampling bias problem of the small-range current type Hall sensor is very little, so that the sampling bias problem brought by the Hall sensor can be greatly reduced.
In addition, whether the MCU is provided with an AD sampling unit or an externally-expanded AD sampling chip, in order to better exert the sampling precision, the voltage value of the acquired AD port needs to be as close as possible to the upper limit of the voltage which can be sampled. For example, the upper limit of the sampling voltage of the AD port of a general MCU is 3V, and then the voltage value of the current signal collected by the hall sensor, after passing through the sampling resistor and the operational amplifier circuit, finally reaches the AD port should be as close to 3V as possible. For this reason, the invention adds the power relays on the basis of adopting the small-range current type Hall sensor, and can switch different numbers of power relays according to different user selection ranges, so that the sum of relays actually flowing through current is just equal to the upper limit current value of the range selected by the user, thus the interference signal acquired by a source (Hall sensor) can be reduced to the greatest extent, the sampling signal is more stable, and the sampling precision is higher. Meanwhile, according to different measuring ranges selected by a user, an analog switch is added on a sampling signal processing branch, and different amplification ratios of sampling signals are realized by selecting the opening and closing of different analog switches, so that the MCU port voltage corresponding to the maximum current under different measuring ranges is always 3V (the upper voltage limit of MCU sampling).
The invention also adds a very low range gear SL, and adopts a smaller Hall sensor, so that the direct current source of the nominal rated current 500A can still keep extremely high sampling and control precision even under the condition of extremely small current (1A or even smaller) output.
Through the technical scheme, the problems that the linearity of the wide-range Hall sensor is poor and the precision is affected when the current is small are well solved, the easy switching of multiple ranges and multiple gears is realized, and therefore the high-precision measurement and control in the full-range are realized, especially the measurement and control precision under the condition of small current or even extremely small current is improved, and the full-range adaptability of the wide-range power supply is greatly improved.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a support high accuracy heavy current acquisition circuit that multispeed switches, its characterized in that includes the current sampling circuit of a plurality of different gears, all current sampling circuit are parallelly connected and all connect power relay on every current sampling circuit place return circuit, and all current sampling circuit's parallel output passes through the difference operational amplifier circuit and is connected with analog switch selection circuit, analog switch selection circuit carries out the amplification of different proportion to the sampling signal through closing different analog switches, and analog switch selection circuit passes through the signal sampling port of rear stage amplifying circuit and MCU to be connected.
2. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 1, wherein each current sampling circuit has the same structure, each current sampling circuit comprises a plurality of parallel Hall elements, one ends of the plurality of parallel Hall elements are connected with a power supply cathode, the other ends of the plurality of parallel Hall elements are connected with one end of a load through a power relay, and the other ends of the load are connected with a power supply anode.
3. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 2, wherein the current sampling circuit is in a high gear, the high-gear current sampling circuit comprises 5 50A Hall elements H1 to H5, the Hall elements H1 to H5 are connected in parallel, one end of each of the Hall elements H1 to H5 connected in parallel is connected with a power supply negative electrode, the other end of each of the Hall elements H1 to H5 connected in parallel is connected with one end of a load through a power relay RealyH, and the other end of the load is connected with a power supply positive electrode.
4. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 2, wherein the current sampling circuit is of a middle gear, the current sampling circuit of the middle gear comprises 3 50A Hall elements M1 to M3, the Hall elements M1 to M3 are connected in parallel, one end of each of the Hall elements M1 to M3 connected in parallel is connected with a power supply cathode, the other end of each of the Hall elements M1 to M3 connected in parallel is connected with one end of a load through a power relay RealyM, and the other end of the load is connected with a power supply anode.
5. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 2, wherein the current sampling circuit is of a low gear, the low-gear current sampling circuit comprises 250A Hall elements L1 and L2, the Hall elements L1 and L2 are connected in parallel, one end of the Hall elements L1 and L2 connected in parallel is connected with a power supply cathode, the other end of the Hall elements L1 and L2 connected in parallel is connected with one end of a load through a power relay RealyL, and the other end of the load is connected with a power supply anode.
6. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 2, wherein the current sampling circuit is in an extremely low gear, the extremely low-gear current sampling circuit comprises a 10A Hall element SL, one end of the Hall element SL is connected with a power negative electrode, the other end of the Hall element SL is connected with one end of a load through a power relay RealySL, and the other end of the load is connected with a power positive electrode.
7. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 2, wherein the input end of the differential operational amplifier circuit is connected with the other ends of the plurality of parallel Hall elements, and the output end of the differential operational amplifier circuit is connected with the analog switch selection circuit.
8. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 7, wherein the analog switch selection circuit comprises a switch SWH, a switch SWM, a switch SWL, a switch SWSL, a resistor RH, a resistor RM, a resistor RL and a resistor RSL, wherein an input end of the differential operational amplifier circuit is connected with the other ends of the plurality of parallel hall elements, one end of the switch SWH, one end of the switch SWM, one end of the switch SWL and one end of the switch SWSL are connected with an output end of the differential operational amplifier circuit, the other ends of the switch SWH, the switch SWM, the other end of the switch SWL and the other end of the switch SWSL are respectively connected with one end of the resistor RH, one end of the resistor RM, one end of the resistor RL and one end of the resistor RSL, and the other end of the resistor RH, the other end of the resistor RL and the other end of the resistor RSL are connected together as parallel output ends of the analog switch selection circuit.
9. The high-precision high-current acquisition circuit supporting multi-gear switching according to claim 8, wherein the post-stage amplification circuit comprises an operational amplifier A21, an operational amplifier A22, a resistor R5 to a resistor R8 and a resistor RX, wherein the in-phase end of the operational amplifier A21 is grounded through the resistor R5, one end of the resistor RX and the opposite end of the operational amplifier A21 are both connected with the parallel output end of the analog switch selection circuit, the other end of the resistor RX is connected with the output end of the operational amplifier A21 and one end of the resistor R6, the other end of the resistor R6, one end of the resistor R7 and the opposite end of the operational amplifier A22 are connected with each other, the in-phase end of the operational amplifier A22 is grounded through the resistor R8, and the other end of the resistor R7 and the output end of the operational amplifier A22 are connected with the signal sampling port of the MCU.
10. The high-precision large-current acquisition method supporting multi-gear switching is characterized in that the method is applied to the high-precision large-current acquisition circuit supporting multi-gear switching according to any one of claims 1-9, when a user selects gears, corresponding power relays are attracted, current flows through Hall elements connected with the power relays, output current sampling signals are all connected in parallel and output to a differential operational amplifier circuit for differential amplification, the differential operational amplifier circuit outputs the signals to an analog switch selection circuit, the analog switch selection circuit is used for amplifying sampling signals in different proportions by closing analog switches according to the selected gears, and the voltage values of the sampling signals finally reaching an MCU under different ranges are all the highest voltage values which can be sampled by the MCU.
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| CN202310431210.5A CN116466123A (en) | 2023-04-18 | 2023-04-18 | High-precision high-current acquisition circuit and method supporting multi-gear switching |
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| CN202310431210.5A CN116466123A (en) | 2023-04-18 | 2023-04-18 | High-precision high-current acquisition circuit and method supporting multi-gear switching |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117330805A (en) * | 2023-12-01 | 2024-01-02 | 昆易电子科技(上海)有限公司 | Automatic gear shifting circuit for current detection and current detection device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117330805A (en) * | 2023-12-01 | 2024-01-02 | 昆易电子科技(上海)有限公司 | Automatic gear shifting circuit for current detection and current detection device |
| CN117330805B (en) * | 2023-12-01 | 2024-02-20 | 昆易电子科技(上海)有限公司 | Automatic gear shifting circuit for current detection and current detection device |
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