CN214539762U - High-voltage direct-current small signal isolation device - Google Patents
High-voltage direct-current small signal isolation device Download PDFInfo
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- CN214539762U CN214539762U CN202120496202.5U CN202120496202U CN214539762U CN 214539762 U CN214539762 U CN 214539762U CN 202120496202 U CN202120496202 U CN 202120496202U CN 214539762 U CN214539762 U CN 214539762U
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Abstract
The utility model belongs to the technical field of industrial control, concretely relates to isolating device of high voltage direct current small-signal, change single-ended signal circuit, signal conditioning circuit and analog-to-digital converter including signal processing circuit, sawtooth generator, error amplifier, comparator, wave filter, digital isolator, difference. The utility model has simple and reliable structure and higher circuit reliability; the performance of low temperature drift and long service life is realized; has good effect of inhibiting the co-interference.
Description
Technical Field
The utility model belongs to the technical field of industrial control, concretely relates to isolating device of high voltage direct current small-signal.
Background
In industrial control, a signal isolation processing circuit is often adopted to acquire alternating current or direct current small-signal analog quantity, generally 4 mA-20 mA current quantity or-10V- +10V voltage quantity, and in order to achieve isolation between signals of primary equipment and secondary equipment on site, an isolation transformer or a common linear optocoupler is often adopted to achieve isolation.
For example, publication number CN207148196U discloses an isolated sampling device for output voltage of a high-voltage direct-current power supply, which relates to the technical field of high-voltage direct-current power supplies; the signal conditioning circuit is connected to the d-terminal and the GND-terminal of the connection, the signal conditioning circuit is connected to the negative feedback current amplifying circuit, and the negative feedback current amplifying circuit is connected to the hall sensor? The output end of the Hall sensor is connected with an output wiring end and a resistor six, the output end of the Hall sensor is connected with an adjustable resistor three, and the adjustable resistor three is connected with a wiring h end; the utility model has the characteristics of the precision is high, linear good, the interference killing feature is strong etc, and the security is high, convenient to use.
As also disclosed in publication No. CN104682946B, a differential to single-ended signal circuit comprises: the amplifier comprises a first amplification stage, a second amplification stage and a feedback resistor; the first amplification stage receives an input differential signal and outputs a path of voltage signal and a path of current signal; the non-inverting input end of the second amplification stage is connected with the output voltage signal of the first amplification stage, and the inverting input end of the second amplification stage is connected with the output current signal of the first amplification stage; the feedback resistor is connected with the inverting input end and the output end of the second amplification stage, converts the output current signal of the first amplification stage into a voltage signal and outputs the voltage signal as a final single-ended signal.
In the prior art, isolation and sampling of a high-voltage direct current signal are generally realized by a voltage divider circuit and a linear optocoupler, and the scheme needs to consider the problems of linearity and service life of the optocoupler and the problem of common-mode interference.
SUMMERY OF THE UTILITY MODEL
To the above insufficiency, the utility model aims at providing an isolating device of little signal of high voltage direct current.
The utility model provides a following technical scheme:
an isolating device for high-voltage direct-current small signals comprises a signal processing circuit, a sawtooth wave generator, an error amplifier, a comparator, a filter, a digital isolator, a differential-to-single-ended signal circuit, a signal regulating circuit and an analog-to-digital converter; the output end of the signal processing circuit is connected with the input end of the error amplifier, the output ends of the error amplifier and the sawtooth wave generator are connected with the input end of the comparator, the output end of the comparator is connected with the input end of the filter, the output end of the filter is connected with the inverting end of the error amplifier, the output end of the comparator is further connected with the input end of the digital isolator, the output end of the digital isolator is connected with the input end of the differential signal to single-ended signal circuit, the output end of the differential signal to single-ended signal circuit is connected with the input end of the signal adjusting circuit, and the output end of the signal adjusting circuit is connected with the input end of the analog-to-digital converter.
The digital isolator is a digital isolation chip with 6000V alternating current isolation level.
The signal processing circuit comprises a first adjustable resistor, a second adjustable resistor, a first resistor, a second resistor and a jumper wire.
The circuit for converting the differential signal into the single-ended signal comprises a first operational amplifier, a second operational amplifier and a third adjustable resistor.
The signal adjusting circuit comprises an operational amplifier III, an adjustable resistor IV, a resistor III, a resistor IV and three capacitors.
The utility model has the advantages that:
1. the utility model has simple and reliable structure and higher circuit reliability;
2. the utility model has the performance of low temperature drift and long service life;
3. the utility model discloses have good suppression effect to the co-interference.
Drawings
Fig. 1 is a schematic block circuit diagram of the present invention;
fig. 2 is a circuit diagram of a signal processing circuit of the present invention;
fig. 3 is a circuit diagram of the differential signal to single-ended signal circuit of the present invention;
fig. 4 is a circuit diagram of the signal conditioning circuit of the present invention.
Detailed Description
As shown in the figure, the high-voltage direct-current small-signal isolating device comprises a signal processing circuit, a sawtooth wave generator, an error amplifier, a comparator, a filter, a digital isolator, a differential-to-single-ended signal circuit, a signal adjusting circuit and an analog-to-digital converter. The output end of the signal processing circuit is connected with the input end of the error amplifier, the output ends of the error amplifier and the sawtooth wave generator are connected with the input end of the comparator, the output end of the comparator is connected with the input end of the filter, the output end of the filter is connected with the inverting end of the error amplifier, the output end of the comparator is further connected with the input end of the digital isolator, the output end of the digital isolator is connected with the input end of the differential signal to single-ended signal circuit, the output end of the differential signal to single-ended signal circuit is connected with the input end of the signal adjusting circuit, and the output end of the signal adjusting circuit is connected with the input end of the analog-to-digital converter.
Specifically, the signal processing circuit comprises a first adjustable resistor VR1, a second adjustable resistor VR2, a first resistor R1, a second resistor R2 and a jumper J1. The first adjustable resistor VR1 and the second adjustable resistor VR2 can be used for adapting to different high-voltage direct-current signals. When the jumper J1 is turned off, the signal processing circuit is in the voltage input mode, and when the jumper J1 is turned on, the signal processing circuit is in the current input mode. The digital isolator is a digital isolation chip with 6000V alternating current isolation level. The digital isolation chip has the design life of up to 60 years and extremely low temperature drift performance. The circuit for converting the differential signal into the single-ended signal comprises a first operational amplifier, a second operational amplifier and an adjustable resistor three VR 3. The operational amplifier I receives input differential signals VIN + and VIN-, outputs a path of voltage signal VO1+ and a path of current signal VO1-, the non-inverting input end VI2+ of the operational amplifier II is connected with the output voltage signal VO1+ of the first amplification stage, and the inverting input end VI 2-of the operational amplifier II is connected with the output current signal VO 1-of the first amplification stage; the adjustable resistor VR3 is connected to the inverting input terminal VI 2-and the output terminal VO of the second operational amplifier, and converts the current signal VO 1-output by the first operational amplifier into a voltage signal Vout, and outputs the voltage signal as a final single-ended signal. The signal conditioning circuit comprises an operational amplifier III, an adjustable resistor IV VR4, a resistor III R3, a resistor IV R4 and three capacitors C1. The capacitance values of the three capacitors C1 are the same.
The sampled high voltage DC signal is processed by a signal processing circuit to obtain a low voltage DC signal, then the low voltage DC signal and a feedback signal filtered by a filter are superposed and then are sent to an inverting terminal of an error amplifier, the inverting terminal of the error amplifier is connected with a reference signal, the output of the error amplifier and a sawtooth wave signal generated by a sawtooth wave generator are jointly sent to a positive input terminal and a negative input terminal of a comparator for comparison, a high frequency PWM signal is obtained at the output terminal of the comparator, the frequency of the PWM signal is fixed, the pulse width and amplitude of the high-voltage direct current signal include the magnitude information of the measured high-voltage direct current signal, the high-frequency PWM signal is sent to the input end of the digital isolator, the output signal of the digital isolator is sent to the circuit for converting the differential signal into the single-ended signal and then converted into the single-ended signal, the single-ended signal is sent to the signal regulating circuit, the signal conditioning circuit is used for filtering and outputting, and the output signal is sent to the analog-to-digital converter to obtain the required digital signal.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. The utility model provides an isolating device of little signal of high voltage direct current which characterized in that: the device comprises a signal processing circuit, a sawtooth wave generator, an error amplifier, a comparator, a filter, a digital isolator, a differential-to-single-ended signal circuit, a signal regulating circuit and an analog-to-digital converter; the output end of the signal processing circuit is connected with the input end of the error amplifier, the output ends of the error amplifier and the sawtooth wave generator are connected with the input end of the comparator, the output end of the comparator is connected with the input end of the filter, the output end of the filter is connected with the inverting end of the error amplifier, the output end of the comparator is further connected with the input end of the digital isolator, the output end of the digital isolator is connected with the input end of the differential signal to single-ended signal circuit, the output end of the differential signal to single-ended signal circuit is connected with the input end of the signal adjusting circuit, and the output end of the signal adjusting circuit is connected with the input end of the analog-to-digital converter.
2. The high-voltage direct current small signal isolation device of claim 1, wherein: the digital isolator is a digital isolation chip with 6000V alternating current isolation level.
3. The high-voltage direct current small signal isolation device of claim 1, wherein: the signal processing circuit comprises a first adjustable resistor, a second adjustable resistor, a first resistor, a second resistor and a jumper wire.
4. The high-voltage direct current small signal isolation device of claim 1, wherein: the circuit for converting the differential signal into the single-ended signal comprises a first operational amplifier, a second operational amplifier and a third adjustable resistor.
5. The high-voltage direct current small signal isolation device of claim 1, wherein: the signal adjusting circuit comprises an operational amplifier III, an adjustable resistor IV, a resistor III, a resistor IV and three capacitors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120496202.5U CN214539762U (en) | 2021-03-09 | 2021-03-09 | High-voltage direct-current small signal isolation device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120496202.5U CN214539762U (en) | 2021-03-09 | 2021-03-09 | High-voltage direct-current small signal isolation device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214539762U true CN214539762U (en) | 2021-10-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120496202.5U Active CN214539762U (en) | 2021-03-09 | 2021-03-09 | High-voltage direct-current small signal isolation device |
Country Status (1)
| Country | Link |
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| CN (1) | CN214539762U (en) |
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2021
- 2021-03-09 CN CN202120496202.5U patent/CN214539762U/en active Active
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