CN220307203U - Wide-range current sampling circuit - Google Patents
Wide-range current sampling circuit Download PDFInfo
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- CN220307203U CN220307203U CN202322009899.0U CN202322009899U CN220307203U CN 220307203 U CN220307203 U CN 220307203U CN 202322009899 U CN202322009899 U CN 202322009899U CN 220307203 U CN220307203 U CN 220307203U
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Abstract
The wide-range current sampling circuit comprises a control unit, a large current detection branch, a micro current detection branch, a first voltage comparator and a second voltage comparator, wherein the large current detection branch comprises a first switching element and a first sampling resistor, and the input end of the first switching element is connected with the first control output end of the control unit; the inverting input end of the first voltage comparator obtains the voltage value of the first sampling resistor, the non-inverting input end of the first voltage comparator is connected with a first reference voltage, and the output end of the first voltage comparator is connected with the first signal input end of the control unit; the structure of the micro-current detection branch is similar to that of the heavy-current detection branch. According to the wide-range current sampling circuit, the sampling of heavy current and micro current is divided into two independent branches, voltage comparators are added to the corresponding branches, sampling voltages are converted into level signals through the comparators, and the control unit switches the sampling circuit according to the level signals.
Description
Technical Field
The present disclosure relates to the field of automotive circuit current detection, and in particular, to a wide-range current sampling circuit.
Background
Under the trend of intelligent automobile parts, the detection requirements on various signals of equipment are higher and higher, the signals are required to be collected, and the sampling precision is required to be high. The sampling of the current in the vehicle device is particularly important, since the magnitude of the load current directly reflects whether the device is operating properly. The small current signal is detected when the equipment is dormant, the loss of the electric quantity of the battery can be estimated, and the large current generated when the equipment is short-circuited possibly causes fire disaster, so that the safety of the automobile is greatly influenced, and the accurate detection of the small current and the large current of the equipment becomes an important technical index.
Disclosure of Invention
To solve the above technical problem, there is provided herein a wide-range current sampling circuit, including:
a control unit;
the high-current detection branch circuit comprises a first switching element and a first sampling resistor which are sequentially connected in series, and the input end of the first switching element is connected with the first control output end of the control unit;
the micro-current detection branch circuit comprises a second switching element and a second sampling resistor which are sequentially connected in series, and the input end of the second switching element is connected with the second control output end of the control unit;
the inverting input end of the first voltage comparator acquires the voltage value of the first sampling resistor, the non-inverting input end of the first voltage comparator is connected with a first reference voltage, and the output end of the first voltage comparator is connected with the first signal input end of the control unit; and
the non-inverting input end of the second voltage comparator acquires the voltage value of the second sampling resistor, the inverting input end of the second voltage comparator is connected with a second reference voltage, and the output end of the second voltage comparator is connected with the second signal input end of the control unit.
Preferably, the control unit is configured to control the first switching element to be turned on and the second switching element to be turned off in a power-on initial state.
Preferably, the control unit is configured to switch the on state of the first switching element/the second switching element according to the detection result of the first signal input terminal in the working state; and switching on states of the first switching element/the second switching element according to a detection result of the second signal input terminal.
Preferably, the first signal input terminal and the second signal input terminal both collect level signals.
Preferably, the first switching element and the second switching element are both NMOS transistors.
Preferably, a high-side driving unit is disposed between the first control output terminal and the first switching element, and between the second control output terminal and the second switching element.
Preferably, the control unit is provided with an AD port for monitoring the current of the high current detection branch/the micro current detection branch in real time.
Preferably, the voltage of the first sampling resistor is input to the inverting input end of the first voltage comparator after passing through the first operational amplifier circuit; the voltage of the second sampling resistor is input to the non-inverting input end of the second voltage comparator after passing through the second operational amplifier circuit.
Preferably, the amplification factor of the first operational amplifier circuit is 10-100; the amplification factor of the second operational amplifier circuit is 100-1000.
By adopting the technical scheme, the sampling of heavy current and micro current is divided into two independent branches, a voltage comparator is added in the corresponding branch, the selection of the current acquisition branch is realized by converting the sampling voltage into a level signal through the comparator, and the control unit switches the sampling circuit according to the level signal. Thus, the circuit structure and control logic are simple, and a wide range of current detection can be realized.
The foregoing and other objects, features and advantages will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments herein or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments herein and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 illustrates a wide range current sampling circuit of an embodiment herein;
fig. 2 shows a flow chart of a control method for implementing a branch switch using the circuit shown in fig. 1.
Description of the drawings:
q1, a first switching element; j1, a first voltage comparator;
r1, a first sampling resistor; TH1, a first reference voltage;
g1, a first operational amplifier circuit; q2, a second switching element;
r2, a second sampling resistor; g2, a second operational amplifier circuit;
j2, a second voltage comparator; TH2, a second reference voltage.
Detailed Description
The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the disclosure. All other embodiments, based on the embodiments herein, which a person of ordinary skill in the art would obtain without undue burden, are within the scope of protection herein.
Embodiments herein provide a wide range current sampling circuit as shown in fig. 1, specifically comprising:
a control unit;
the high-current detection branch circuit comprises a first switching element Q1 and a first sampling resistor R1 which are sequentially connected in series, wherein the input end of the first switching element Q1 is connected with a first control output end (can be understood as an I/O port IO 1) of the control unit;
the micro-current detection branch circuit comprises a second switching element Q2 and a second sampling resistor R2 which are sequentially connected in series, and the input end of the second switching element Q2 is connected with a second control output end (which can be understood as an I/O port IO 2) of the control unit;
the inverting input end of the first voltage comparator J1 obtains the voltage value of the first sampling resistor R1, the non-inverting input end of the first voltage comparator J1 is connected with a first reference voltage TH1, and the output end of the first voltage comparator J1 is connected with a first signal input end (which can be understood as an I/O port IO 3) of the control unit; and
the non-inverting input end of the second voltage comparator J2 obtains the voltage value of the second sampling resistor R2, the inverting input end of the second voltage comparator J2 is connected with the second reference voltage TH2, and the output end of the second voltage comparator J2 is connected with the second signal input end (which can be understood as an I/O port IO 4) of the control unit.
According to the wide-range current sampling circuit, the sampling of heavy current and micro current is divided into two independent branches, voltage comparators are added in the corresponding branches, sampling voltages are converted into level signals through the comparators, and the control unit switches the sampling circuit according to the level signals. Thus, the circuit structure and control logic are simple, and a wide range of current detection can be realized.
It can be understood that the first reference voltage TH1 and the second reference voltage TH2 are fixed voltages preset for the first voltage comparator J1 and the second voltage comparator J2, and the current is judged to be a large current or a small current by comparing the sampled voltage values with the preset fixed voltage values. That is, the setting of the reference voltage determines the threshold value of the magnitude current. It is further understood that the values of the first reference voltage TH1 and the second reference voltage TH2 may be set according to actual needs, and are generally in the range of 0-3.3V.
With continued reference to fig. 1, the voltage of the first sampling resistor R1 is input to the inverting input terminal of the first voltage comparator J1 after passing through the first operational amplifier circuit G1; the voltage of the second sampling resistor R2 is input to the non-inverting input terminal of the second voltage comparator J2 after passing through the second operational amplifier circuit G2.
Specifically, in some embodiments, the amplification factor of the first operational amplifier circuit G1 is 10-100; the amplification factor of the second operational amplifier circuit G2 is 100-1000.
As shown in fig. 1, the first switching element Q1 and the second switching element Q2 are both NMOS (N-Metal-Oxide-Semiconductor) tubes. Its advantages are low internal resistance, low loss and high current channel switch.
Further, a high-side driving unit is disposed between the first control output terminal and the first switching element Q1, and between the second control output terminal and the second switching element Q2. Because normally, the NMOS transistor requires a high-side drive unit to turn on and off.
In some embodiments, the control unit is typically further provided with an AD port for monitoring the current of the high current detection branch/micro current detection branch in real time. It can be understood that the circuit divides the sampling of the large current and the small current into two independent branches, the selection of the current sampling circuit is realized through the conversion of the voltage comparator, thus the sampling signals of the large current and the micro current can share one AD port, and only the code conversion is needed to be changed.
In some embodiments, the control unit may be configured to control the first switching element Q1 to be turned on and the second switching element Q2 to be turned off in a power-on initial state. Therefore, the high-current detection branch is led in by the guide, and the micro-current detection branch is prevented from being damaged by direct high current after power-on.
More specifically, the control unit may be configured to switch the on state of the first switching element Q1/second switching element Q2 according to the detection result of the first signal input terminal in the operating state; and switching the on state of the first switching element Q1/the second switching element Q2 according to the detection result of the second signal input terminal.
More specifically, the first signal input and the second signal input each collect a level signal.
Next, with reference to fig. 2, the control logic of the wide-range current sampling circuit herein is described in detail.
After power-on, the I/O port IO2 of the control unit outputs a high level to control the first switching element Q1 to be conducted (a pilot is conducted to a large current detection branch circuit, so that the micro current detection branch circuit is prevented from being damaged by direct large current after power-on), and power supply to a load is realized.
Next, the large current detection branch flows through the current I1, is converted into a voltage signal by the first sampling resistor R1, and is amplified by the first operational amplifier circuit G1, and then enters the AD port ADC1 of the control chip, and meanwhile, the signal is compared with the first reference voltage TH1, and the signal value is: u1=r1×i1×g1; if U1> TH1, the first voltage comparator J1 outputs a low level (which indicates that the load current is large at the moment) to the I/O port IO3 of the control unit, and the operation of the heavy current detection branch is continuously kept; if U1< TH1 (in this case, the load current is smaller), the I/O port IO3 of the control unit outputs a high level to the control unit, in this case, the control unit controls the I/O port IO2 to output a high level and the IO1 to output a low level, the second switching element Q2 is turned on, and the first switching element Q1 is turned off, and in this case, the micro-current detection branch is switched.
Similar to the operation of the heavy current detection branch, the sampling amplification signal of the micro current detection branch is u2=r2×i2×g2. Wherein U2> the second reference voltage TH2, the second voltage comparator J2 outputs a high level (indicating that the load current is large at this time), and U2< TH2 outputs a low level (indicating that the load current is small at this time). If U2 is smaller than TH2, the I/O port IO4 outputs a low level to the control unit, and the micro-current detection branch is kept running; if U2> TH2, the I/O port IO4 outputs a high level to the control unit, at this time, the control unit controls the I/O port IO2 to output a low level and the IO1 to output a high level, the second switching element Q2 is turned off, and the first switching element Q1 is turned on, at this time, the switching is switched to the heavy current detection branch.
It should also be understood that in embodiments herein, the term "and/or" is merely one relationship that describes an associated object, meaning that three relationships may exist. For example, a and/or B may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
Those of ordinary skill in the art will appreciate that the elements and algorithm steps described in connection with the embodiments disclosed herein may be embodied in electronic hardware, in computer software, or in a combination of the two, and that the elements and steps of the examples have been generally described in terms of function in the foregoing description to clearly illustrate the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the elements may be selected according to actual needs to achieve the objectives of the embodiments herein.
In addition, each functional unit in the embodiments herein may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
Specific examples are set forth herein to illustrate the principles and embodiments herein and are merely illustrative of the methods herein and their core ideas; also, as will occur to those of ordinary skill in the art upon reading the teachings herein, the present disclosure should not be construed as limited in scope to the specific embodiments and applications herein.
Claims (9)
1. A wide-range current sampling circuit, comprising:
a control unit;
the high-current detection branch circuit comprises a first switching element and a first sampling resistor which are sequentially connected in series, and the input end of the first switching element is connected with the first control output end of the control unit;
the micro-current detection branch circuit comprises a second switching element and a second sampling resistor which are sequentially connected in series, and the input end of the second switching element is connected with the second control output end of the control unit;
the inverting input end of the first voltage comparator acquires the voltage value of the first sampling resistor, the non-inverting input end of the first voltage comparator is connected with a first reference voltage, and the output end of the first voltage comparator is connected with the first signal input end of the control unit; and
the non-inverting input end of the second voltage comparator acquires the voltage value of the second sampling resistor, the inverting input end of the second voltage comparator is connected with a second reference voltage, and the output end of the second voltage comparator is connected with the second signal input end of the control unit.
2. The wide range current sampling circuit of claim 1, wherein the control unit is configured to control the first switching element to be on and the second switching element to be off in a power-on initial state.
3. The wide-range current sampling circuit according to claim 2, wherein the control unit is configured to switch the on state of the first switching element/the second switching element according to the detection result of the first signal input terminal in an operating state; and switching on states of the first switching element/the second switching element according to a detection result of the second signal input terminal.
4. The wide range current sampling circuit of claim 3 wherein said first signal input and said second signal input each capture a level signal.
5. The wide range current sampling circuit of claim 1 wherein the first switching element and the second switching element are NMOS transistors.
6. The wide range current sampling circuit of claim 5 wherein a high side drive unit is provided between said first control output and said first switching element and between said second control output and said second switching element.
7. The wide-range current sampling circuit according to claim 1, wherein the control unit is provided with an AD port for monitoring the current of the high current detection branch/the micro current detection branch in real time.
8. The wide-range current sampling circuit of claim 1, wherein the voltage of the first sampling resistor is input to the inverting input terminal of the first voltage comparator after passing through a first operational amplifier circuit; the voltage of the second sampling resistor is input to the non-inverting input end of the second voltage comparator after passing through the second operational amplifier circuit.
9. The wide range current sampling circuit of claim 8 wherein the first op-amp circuit has a magnification factor of 10-100; the amplification factor of the second operational amplifier circuit is 100-1000.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322009899.0U CN220307203U (en) | 2023-07-28 | 2023-07-28 | Wide-range current sampling circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322009899.0U CN220307203U (en) | 2023-07-28 | 2023-07-28 | Wide-range current sampling circuit |
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| Publication Number | Publication Date |
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| CN220307203U true CN220307203U (en) | 2024-01-05 |
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| CN202322009899.0U Active CN220307203U (en) | 2023-07-28 | 2023-07-28 | Wide-range current sampling circuit |
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| CN (1) | CN220307203U (en) |
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- 2023-07-28 CN CN202322009899.0U patent/CN220307203U/en active Active
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