阅读说明：本技术 一种简单隔离电压门限判别电路 (Simple isolation voltage threshold discrimination circuit ) 是由 林益锋 毋蒙 褚衍超 唐德佳 许东欢 于 2020-12-04 设计创作，主要内容包括：本发明公开了一种简单隔离电压门限判别电路,包括带隔离电源的磁隔离芯片、采样电阻网络、电压基准芯片和电压比较芯片；所述带隔离电源的磁隔离芯片将原端电源转换为隔离端电源；所述采样电阻网络并接在被测电压两端；电压基准芯片提供基准电压；电压比较芯片对采样电阻网络的输出电压和电压基准进行比较,输出判别结果；所述带隔离电源的磁隔离芯片将判别结果隔离后发送至原端。现有技术需要根据每个电压基准二极管的实测电压调整外部电阻值,以达到校正电压门限的目的。本发明采用带隔离电源的磁隔离芯片供给隔离测电源,因此可以选用精度更高、一致性更好的电压基准芯片提供基准电压,省去了调整外部电阻进行校正的步骤。(The invention discloses a simple isolation voltage threshold discrimination circuit, which comprises a magnetic isolation chip with an isolation power supply, a sampling resistor network, a voltage reference chip and a voltage comparison chip, wherein the sampling resistor network is connected with the magnetic isolation chip; the magnetic isolation chip with the isolation power supply converts a primary power supply into an isolation power supply; the sampling resistor network is connected in parallel with two ends of the voltage to be measured; the voltage reference chip provides a reference voltage; the voltage comparison chip compares the output voltage of the sampling resistor network with a voltage reference and outputs a judgment result; and the magnetic isolation chip with the isolation power supply isolates the judgment result and then sends the result to the original end. In the prior art, an external resistance value needs to be adjusted according to the measured voltage of each voltage reference diode so as to achieve the purpose of correcting the voltage threshold. The magnetic isolation chip with the isolation power supply is used for supplying the isolation power supply, so that the voltage reference chip with higher precision and better consistency can be selected to supply the reference voltage, and the step of adjusting the external resistor for correction is omitted.)

1. A simple isolation voltage threshold discrimination circuit is characterized in that: the device comprises a magnetic isolation chip with an isolation power supply, a sampling resistor network, a voltage reference chip and a voltage comparison chip;

the magnetic isolation chip with the isolation power supply converts a primary power supply into an isolation power supply;

the sampling resistor network is connected in parallel with two ends of the voltage to be measured;

the voltage reference chip provides a reference voltage;

the voltage comparison chip compares the output voltage of the sampling resistance network with a voltage reference and outputs a judgment result;

and the magnetic isolation chip with the isolation power supply isolates the judgment result and then sends the result to the original end.

2. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: pins 1 and 7 of the magnetic isolation chip with the isolation power supply are connected with an original end 5V power supply, pins 2 and 8 are connected with a 5V power supply ground, a pin 16 outputs the isolation end power supply, and pins 9 and 15 are connected with an isolation end power supply ground; the 11 pins receive the discrimination result signal of the voltage comparison chip, and the 6 pins are the output signal of the original end.

3. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: one end of R1 of the sampling resistor network is connected with the positive end of the voltage to be measured, the other end of the R1 of the sampling resistor network is connected with R2, and the other end of R2 of the sampling resistor network is connected with the negative end of the voltage to be measured; the intermediate joint of the R1 and the R2 is connected with the negative input end of the voltage comparator.

4. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: the voltage reference chip uses an isolated 5V power supply, and the voltage output of the voltage reference chip is connected with the positive input end of the voltage comparator.

5. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: the voltage comparison chip uses an isolation power supply, and the output end of the voltage comparison chip is pulled up to the isolation power supply through a resistor.

6. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: the primary end voltage is a 5V power supply.

7. The simple isolation voltage threshold discrimination circuit of claim 1, wherein: the negative end of the measured voltage is in short circuit with the isolation power ground.

8. The simple isolation voltage threshold discrimination circuit of claim 3, wherein: the value of R1 is 100k omega, and the value of R2 is 30k omega.

Technical Field

The invention belongs to the technical field of voltage signal isolation, and particularly relates to threshold judgment of analog direct current voltage.

Background

When the isolation high voltage threshold determination is needed, a voltage reference diode is generally used as a voltage reference, and a typical device is 2DW 232. However, the 2DW232 output voltage serving as the voltage reference has a large drift range and a large discrete type of devices in the same batch, so that the voltage threshold judgment needs to be corrected, and the complexity is increased.

Disclosure of Invention

In order to simplify the design and maintenance of the isolation voltage threshold discrimination, the invention provides a simple isolation voltage threshold discrimination circuit.

The invention adopts the following technical scheme: a simple isolation voltage threshold discrimination circuit comprises a magnetic isolation chip with an isolation power supply, a sampling resistor network, a voltage reference chip and a voltage comparison chip; the magnetic isolation chip with the isolation power supply converts a primary power supply into an isolation power supply; the sampling resistor network is connected in parallel with two ends of the voltage to be measured; the voltage reference chip provides a reference voltage; the voltage comparison chip compares the output voltage of the sampling resistor network with a voltage reference and outputs a judgment result; and the magnetic isolation chip with the isolation power supply isolates the judgment result and then sends the result to the original end.

The magnetic isolation chip with the isolation power supply can realize signal interaction between the isolation end and the original end and also complete power supply generation of the isolation end, and the voltage reference chip can output reference voltage with higher precision and small discreteness by using the power supply of the isolation end, so that the voltage threshold is more accurate and better in consistency, and calibration is not needed.

Preferably, pins 1 and 7 of the magnetic isolation chip with the isolation power supply are connected with an original end 5V power supply, pins 2 and 8 are connected with a 5V power supply ground, a pin 16 outputs the isolation end power supply, and pins 9 and 15 are connected with an isolation end power supply ground; the 11 pins receive the discrimination result signal of the voltage comparison chip, and the 6 pins are the output signal of the original end.

Furthermore, one end of R1 of the sampling resistor network is connected with the positive end of the voltage to be measured, the other end of R2 of the sampling resistor network is connected with the negative end of the voltage to be measured, and the other end of R2 of the sampling resistor network is connected with the negative end of the voltage to be measured; the intermediate joint of the R1 and the R2 is connected with the negative input end of the voltage comparator.

Further, the voltage reference chip uses an isolated 5V power supply, and the voltage output of the voltage reference chip is connected with the positive input terminal of the voltage comparator.

Furthermore, the voltage comparison chip uses an isolation power supply, and the output end is pulled up to the isolation power supply through a resistor.

Further, the negative end of the measured voltage is in short circuit with the isolation power ground.

Specifically, the primary terminal voltage is a 5V power supply.

Compared with the prior art, the invention has the beneficial effects that:

in the prior art, an external resistance value needs to be adjusted according to the measured voltage of each voltage reference diode so as to achieve the purpose of correcting the voltage threshold. The magnetic isolation chip with the isolation power supply is used for supplying the isolation power supply, so that the voltage reference chip with higher precision and better consistency can be selected to supply the reference voltage, and the step of adjusting the external resistor for correction is omitted.

Drawings

The invention will be further explained with reference to the drawings and examples.

Fig. 1 is a schematic diagram of a simple isolation voltage threshold discrimination circuit according to the present invention.

Detailed Description

Embodiments of the present invention are described below with reference to the accompanying drawings:

referring to fig. 1, the simple isolation voltage threshold determination circuit of the present embodiment includes a magnetic isolator D1 with an isolation power supply, sampling resistor networks R1 to R2, a voltage reference chip N1, and a voltage comparison chip N2.

Wherein D1 completes the output of the isolated side power supply. And R1 in the resistor network is connected in series with R2 and then is connected at two ends of the measured voltage, and the negative end of the measured voltage is in short circuit with the ground of the isolation power supply. N1 outputs a reference voltage using the isolated side power supply. The negative input end of N2 is connected with the joint of R1 and R2, and the positive input end is connected with the output end of N1. The output end of N1 is connected with D1, and is isolated and converted by D1 and then output to the original end.

In this embodiment, the voltage at the primary terminal is 5V, and ADuM6402 is used as D1. Pins 1 and 7 of the D1 are connected with the 5V voltage of the original end, and pins 2 and 8 are connected with the 5V voltage ground; the 16 pin and the 10 pin are in short circuit with a 5V power supply of the output isolation end, and the 9 pin and the 15 pin are power supply grounds of the isolation end; the pin 11 is connected with the pin 7 of the N1, and the pin 6 outputs the feedback signal after being isolated. The primary power input of D1 is connected in parallel with capacitor C1.

In the embodiment, the resistor networks R1 and R2 are connected in series and then connected in parallel at two ends of the measured voltage, the negative end of the measured voltage is in short circuit with the isolated 5V power ground, and the contact points of R1 and R2 are connected with the pin 3 of N2. R1 takes on 100k omega, R2 takes on 30k omega.

In this embodiment, N1 is AD580, pin 1 is connected to the 5V power supply of the isolation terminal, pin 3 is connected to the power ground of the isolation terminal, and a capacitor C2 is connected in parallel between pin 1 and pin 3; the 2 pin is connected with the 2 pin of the N2.

In this embodiment, N2 is LM111J, pin 8 is connected to isolated 5V power, pin 1 and pin 4 are connected to isolated 5V power ground, and pin 7 is pulled up through resistor R3.

The 8 pin of the voltage comparator is also connected with a capacitor C4 in parallel to an isolated 5V power ground, and the 3 pin is connected with a capacitor C3 in parallel to the negative terminal of the measured voltage.

When the isolation high voltage threshold determination is needed, a voltage reference diode is generally used as a voltage reference, and a typical device is 2DW 232. However, the 2DW232 output voltage serving as the voltage reference has a large drift range and the discreteness of devices in the same batch is also large, so that the voltage threshold judgment needs to be corrected, and the complexity is increased.

The magnetic isolation chip with the isolation power supply is used for supplying the isolation power supply, so that the voltage reference chip with higher precision and better consistency can be selected to supply the reference voltage, and the step of adjusting the external resistor for correction is omitted.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and any simple changes or equivalent substitutions of the technical solutions that can be made obvious by those skilled in the art within the technical scope of the present invention are within the scope of the present invention.