CN215116497U - Current detection circuit - Google Patents
Current detection circuit Download PDFInfo
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- CN215116497U CN215116497U CN202120793859.8U CN202120793859U CN215116497U CN 215116497 U CN215116497 U CN 215116497U CN 202120793859 U CN202120793859 U CN 202120793859U CN 215116497 U CN215116497 U CN 215116497U
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Abstract
The utility model provides a current detection circuit, which comprises a signal amplification unit, wherein the input end of the signal amplification unit is connected with a sampling circuit for current sampling and outputs an amplification signal; the ADC module inputs the amplified signal, performs analog-to-digital conversion on the amplified signal and outputs a digital signal; and the controller inputs a digital signal and calculates the detected current value. The utility model adopts the built-in programmable gain amplifier and no external component, solves the problem that the amplification precision of the operational amplifier circuit is greatly influenced by the external component in the prior art, and improves the stability of the amplification precision of the operational amplifier circuit; the current sampling is carried out on the two ends of the sampling device in the sampling circuit, the current sampling is accurate, and the obtained current detection result is accurate.
Description
Technical Field
The utility model relates to a current detection technical field especially relates to a current detection circuit.
Background
The current detection circuit of the existing current detection circuit, especially the current detection circuit of the kitchen appliance heated by electromagnetic conversion, such as the current detection circuit of an induction cooker or an IH electric cooker, is shown in figure 1, the traditional current detection adopts a built-in operational amplifier circuit, the operational amplifier circuit is formed by R2, R1, C10 and the inner OPA, and then the current is detected by an ADC module. This solution has the following problems: 1. the amplification precision of the operational amplifier circuit is greatly influenced by external components; 2. the current sampling is single-ended sampling, and current signals cannot be accurately sampled in real time, so that the current sampling is not accurate, and the current detection is not accurate.
SUMMERY OF THE UTILITY MODEL
Not enough to exist among the prior art, the utility model provides a current detection circuit, it has solved the amplification precision of the operational amplifier circuit that exists among the prior art and has influenced by outside components and parts big, the single-ended sampling of electric current leads to the unsafe problem of current detection.
The embodiment of the utility model provides a current detection circuit, it includes signal amplification unit, the sampling circuit who uses is inserted to the input of signal amplification unit carries out current sampling, outputs and amplifies the signal; the signal amplification unit comprises a first resistor, a second resistor, a programmable gain amplifier and a reference voltage module; one end of the first resistor is connected with one end of a sampling device in the sampling circuit, the other end of the first resistor is connected with the first input end of the programmable gain amplifier, the second input end of the programmable gain amplifier is connected with the other end of the sampling device and the output end of the reference voltage module, and the two ends of the second resistor are respectively connected with the first input end and the output end of the programmable gain amplifier; the ADC module is used for performing analog-to-digital conversion on the output signal of the signal amplification unit and outputting a digital signal; and the controller is used for calculating the detected current value according to the digital signal.
The current detection circuit further comprises an anti-interference unit, wherein the first end of the anti-interference unit is connected with the second input end of the programmable gain amplifier, the second end of the anti-interference unit is connected with the other end of the sampling device, and the third end of the anti-interference unit is connected with one end of the reference voltage module.
Further, the anti-interference unit comprises a third resistor and a fourth resistor; one end of the third resistor is connected with the other end of the sampling device, and the other end of the third resistor is connected with the second input end of the programmable gain amplifier; one end of the fourth resistor is connected with the reference voltage module, and the other end of the fourth resistor is connected with the second input end of the programmable gain amplifier.
Further, the reference voltage module comprises an analog switch and a reference voltage group, and the controller controls the analog switch to be connected with/disconnected from the reference voltage group.
Further, the reference voltage group comprises a Verf module and a GND module, and the controller controls the analog switch to be connected/disconnected with the Verf module or the GND module.
Furthermore, the current detection circuit further comprises a current surge protection unit, and the current surge protection unit is connected with the output end of the signal amplification unit.
Further, the current surge protection unit comprises a voltage division group and a surge protection group; the input end of the voltage division group is connected with the output end of the signal amplification unit, and the output end of the voltage division group is connected with the input end of the surge protection group.
Furthermore, the voltage division group includes a plurality of voltage division resistors, an input terminal of a first voltage division resistor of the voltage division group is connected to an output terminal of the programmable gain amplifier, an output terminal of the first voltage division resistor is connected to one end of a second voltage division resistor, and another end of the second voltage division resistor is grounded.
Further, the surge protection group comprises a comparator, a DAC module and a pulse width generator; the first input end of the comparator is connected with the output end of the first voltage-dividing resistor, the second input end of the comparator is connected with the output end of the DAC module, the output end of the comparator is connected with the input end of the pulse width generator, and the output end of the pulse width generator is connected with the controller.
Further, the surge protection group further comprises an LDO module, and the LDO module is connected with the input end of the DAC module.
Compared with the prior art, the embodiment has the following beneficial effects:
by adopting the built-in programmable gain amplifier and no external component, the problem that the amplification precision of the operational amplifier circuit is greatly influenced by the external component in the prior art is solved, and the stability of the amplification precision of the operational amplifier circuit is improved; the current sampling is carried out on the two ends of the sampling device in the sampling circuit, the current sampling is accurate, and the obtained current detection result is accurate.
Drawings
Fig. 1 is a schematic diagram of a conventional current detection circuit.
Fig. 2 is a schematic circuit diagram of a current detection circuit according to an embodiment of the present invention.
Fig. 3 is a schematic circuit diagram of another current detection circuit according to an embodiment of the present invention.
Fig. 4 is a schematic circuit diagram of another current detection circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The functional units of the same reference numerals in the examples of the present invention have the same and similar structures and functions.
Example one
As shown in fig. 2, an embodiment of the present invention provides a current detection circuit, which includes a signal amplification unit, an ADC module, and a controller; the input end of the signal amplification unit is connected to a used sampling circuit for current sampling, and an amplified signal is output; the signal amplification unit comprises a first resistor R1, a second resistor R2, a programmable gain amplifier PGA and a reference voltage module; one end of the first resistor R1 is connected to one end of a sampling device R10 in the sampling circuit, the other end of the first resistor R1 is connected to a first input end of the programmable gain amplifier PGA, a second input end of the programmable gain amplifier PGA is connected to the other end of the sampling device R10 and an output end of the reference voltage module, and two ends of the second resistor R2 are connected to the first input end and the output end of the programmable gain amplifier PGA, respectively; the ADC module is used for performing analog-to-digital conversion on the output signal of the signal amplification unit and outputting a digital signal; the controller is used for calculating the detected current value according to the digital signal.
In this embodiment, the input terminal of the ADC module is connected to the output terminal of the programmable gain amplifier PGA, and the controller is connected to the output terminal of the ADC module.
In this embodiment, the second resistor R2 is a variable resistor, and the controller changes the resistance of the second resistor R2 to adjust the amplification factor of the signal amplification unit, so that the application environment of the current detection circuit is wider. In this embodiment, the first input terminal of the programmable gain amplifier PGA is an inverting input terminal, and the second input terminal of the programmable gain amplifier PGA is a non-inverting input terminal.
In this embodiment, the reference voltage module includes an analog switch and a reference voltage group, the reference voltage group includes a Verf module and a GND module, and the controller controls the analog switch to be connected to the Verf module or the GND module.
The utility model provides two kinds of reference voltage, prior art's programmable gain amplifier PGA all is single power supply. When one input end of the programmable gain amplifier PGA is connected with the GND module, the voltage of the other input end is required to be smaller than that of the GND module, otherwise, the programmable gain amplifier PGA cannot amplify signals. In order to increase the application environment of the current detection circuit, a reference voltage, namely a Verf module, is added for the selection of the controller, and when the voltage of one input end of the programmable gain amplifier PGA is larger than that of the GND module, the controller controls the analog switch to be connected and conducted with the Verf module.
Compared with the prior art, the embodiment has the following beneficial effects:
by adopting the built-in programmable gain amplifier and no external component, the problem that the amplification precision of the operational amplifier circuit is greatly influenced by the external component in the prior art is solved, and the stability of the amplification precision of the operational amplifier circuit is improved; the current sampling is carried out on the two ends of the sampling device in the sampling circuit, the current sampling is accurate, and the obtained current detection result is accurate.
Example two
As shown in fig. 3, in this embodiment, on the basis of the first embodiment, the current detection circuit further includes an anti-interference unit, a first end of the anti-interference unit is connected to the second input terminal of the programmable gain amplifier, a second end of the anti-interference unit is connected to the other end of the sampling device, and a third end of the anti-interference unit is connected to one end of the reference voltage module.
The anti-interference unit in the embodiment comprises a third resistor R3 and a fourth resistor R4; the fourth resistor R4 is a variable resistor, one end of the third resistor R3 is connected to the other end of the sampling device R10, and the other end of the third resistor R3 is connected to the second input terminal of the programmable gain amplifier PGA; one end of the fourth resistor R4 is connected to the reference voltage module, and the other end of the fourth resistor R4 is connected to the second input terminal of the programmable gain amplifier PGA.
The anti-interference unit, the signal amplification unit and the reference voltage module form a differential amplification circuit, differential mode signals are amplified, common mode signals are restrained and filtered, and the influence of external environmental factors on current detection is eliminated.
EXAMPLE III
As shown in fig. 4, in this embodiment, on the basis of the second embodiment, the current detection circuit further includes a current surge protection unit, and the current surge protection unit is connected to the output end of the signal amplification unit.
The current surge protection unit in this embodiment includes a voltage division group and a surge protection group; the input end of the voltage division group is connected with the output end of the signal amplification unit, the output end of the voltage division group is connected with the input end of the surge protection group, the voltage division group divides the output voltage of the signal amplification unit, and the voltage input into the surge protection group is guaranteed to be the acceptable safe voltage of the surge protection group.
In this embodiment, the voltage dividing group includes two voltage dividing resistors, an input end of a first voltage dividing resistor R5 is connected to an output end of the programmable gain amplifier PGA, an output end of the first voltage dividing resistor R5 is connected to one end of a second voltage dividing resistor R6, and the other end of the second voltage dividing resistor R6 is grounded.
The surge protection group comprises a comparator, a DAC module and a pulse width generator PPG; the first input end of the comparator is connected with the output end of the first voltage dividing resistor R5, the second input end of the comparator is connected with the output end of the DAC module, the output end of the comparator is connected with the input end of the pulse width generator PPG, and the output end of the pulse width generator PPG is connected with the controller.
The voltage dividing group divides the output voltage of the programmable gain amplifier PGA and then inputs the voltage to the comparator. When the voltage of the first input end of the comparator is smaller than the voltage of the second input end of the comparator, the pulse width generator PPG outputs high level, an external circuit connected with the pulse width generator PPG is conducted through the controller, and the external circuit works normally.
When the current surge is generated, the voltage of the first input end of the comparator is greater than the voltage of the second input end of the comparator, the output state of the comparator is changed, the pulse width generator PPG receives the changed signal, and the external circuit connected with the pulse width generator PPG is turned off through the output of the controller, so that the current surge protection is realized.
The surge protection group of this embodiment further includes an LDO module, and the LDO module is connected to the input terminal of the DAC module. The LDO module provides power to the DAC module.
Finally, it is noted that the above embodiments are only used for illustrating the technical solutions of the present invention/utility model and not for limiting, and although the present invention/utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solutions of the present invention/utility model without departing from the spirit and scope of the technical solutions of the present invention/utility model, which should be covered in the scope of the claims of the present invention/utility model.
Claims (10)
1. A current sense circuit, comprising:
the input end of the signal amplification unit is connected to a used sampling circuit for current sampling, and an amplified signal is output; the signal amplification unit comprises a first resistor, a second resistor, a programmable gain amplifier and a reference voltage module; one end of the first resistor is connected with one end of a sampling device in the sampling circuit, the other end of the first resistor is connected with the first input end of the programmable gain amplifier, the second input end of the programmable gain amplifier is connected with the other end of the sampling device and the output end of the reference voltage module, and the two ends of the second resistor are respectively connected with the first input end and the output end of the programmable gain amplifier;
the ADC module is used for performing analog-to-digital conversion on the output signal of the signal amplification unit and outputting a digital signal;
and the controller is used for calculating the detected current value according to the digital signal.
2. The current detection circuit according to claim 1, further comprising an anti-interference unit, wherein a first end of the anti-interference unit is connected to the second input terminal of the programmable gain amplifier, a second end of the anti-interference unit is connected to the other end of the sampling device, and a third end of the anti-interference unit is connected to one end of the reference voltage module.
3. A current sensing circuit as claimed in claim 2, wherein the immunity unit comprises:
a third resistor and a fourth resistor; one end of the third resistor is connected with the other end of the sampling device, and the other end of the third resistor is connected with the second input end of the programmable gain amplifier; one end of the fourth resistor is connected with the reference voltage module, and the other end of the fourth resistor is connected with the second input end of the programmable gain amplifier.
4. A current sensing circuit according to any of claims 1 to 3, wherein the reference voltage module comprises: the controller controls the analog switch to be connected/disconnected with the reference voltage group.
5. The current sense circuit of claim 4 wherein the set of reference voltages comprises: the controller controls the analog switch to be connected or disconnected with the Verf module or the GND module.
6. The current sense circuit of claim 5, wherein the current sense circuit further comprises: and the current surge protection unit is connected with the output end of the signal amplification unit.
7. The current sensing circuit of claim 6, wherein the current surge protection unit comprises: a voltage division group and a surge protection group; the input end of the voltage division group is connected with the output end of the signal amplification unit, and the output end of the voltage division group is connected with the input end of the surge protection group.
8. The current sense circuit of claim 7, wherein the voltage divider set comprises: the input end of a first divider resistor of the voltage dividing group is connected with the output end of the programmable gain amplifier, the output end of the first divider resistor is connected with one end of a second divider resistor, and the other end of the second divider resistor is grounded.
9. A current sensing circuit as claimed in claim 8, wherein said surge protection bank comprises: the device comprises a comparator, a DAC module and a pulse width generator; the first input end of the comparator is connected with the output end of the first voltage-dividing resistor, the second input end of the comparator is connected with the output end of the DAC module, the output end of the comparator is connected with the input end of the pulse width generator, and the output end of the pulse width generator is connected with the controller.
10. A current sensing circuit as claimed in claim 9, wherein said surge protection bank further comprises: and the LDO module is connected with the input end of the DAC module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120793859.8U CN215116497U (en) | 2021-04-16 | 2021-04-16 | Current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120793859.8U CN215116497U (en) | 2021-04-16 | 2021-04-16 | Current detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215116497U true CN215116497U (en) | 2021-12-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120793859.8U Active CN215116497U (en) | 2021-04-16 | 2021-04-16 | Current detection circuit |
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| Country | Link |
|---|---|
| CN (1) | CN215116497U (en) |
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2021
- 2021-04-16 CN CN202120793859.8U patent/CN215116497U/en active Active
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