CN218866380U

CN218866380U - Reference circuit for realizing high isolation voltage from primary side to secondary side

Info

Publication number: CN218866380U
Application number: CN202223578837.3U
Authority: CN
Inventors: 曾祥龙; 庄仙海; 张召生
Original assignee: Shenzhen Zhenhua Microelectronics Co Ltd
Current assignee: Shenzhen Zhenhua Microelectronics Co Ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-04-14
Anticipated expiration: 2032-12-30

Abstract

The utility model provides a by former limit to vice limit realize high isolation voltage's reference circuit, belong to electronic circuit technical field, including bleeder circuit, isolation amplifier circuit, than arranging amplifier circuit, signal conditioning circuit and sampling circuit, bleeder circuit's output and isolation amplifier circuit's input are connected, and isolation amplifier circuit's output and than arranging amplifier circuit's input and being connected, than arranging amplifier circuit's output and being connected with signal conditioning circuit's input, signal conditioning circuit's output and sampling circuit's input are connected. The utility model discloses applied isolation operational amplifier has solved voltage reference control signal on the primary side, and sampling circuit is in the not problem altogether that the secondary side brought, and isolation voltage is up to 5000VDC. The circuit control mode is simple, and compared with other isolation modes, the circuit control mode has the advantages of small size and high precision, and has wide application prospect in occasions with high aerospace power density.

Description

Reference circuit for realizing high isolation voltage from primary side to secondary side

Technical Field

The utility model relates to an electronic circuit technical field especially relates to a realize high isolation voltage's reference circuit by former limit to vice limit.

Background

The existing adjustable charger on the market does not have the function of adjusting the standby current, and the control signal is generally placed on the secondary side. However, according to the requirements of customers, an adjustable charger which has a current adjustable function and a control signal is placed on a primary side to realize constant current of a secondary side is needed. If the circuit uses the optical coupler to isolate, linear optical couplers on the market are fewer and have insufficient precision, and the circuit is greatly influenced by irradiation. If magnetic isolation is adopted, the number of devices is large, the size of the module is limited, and the implementation cannot be realized.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a by former limit to vice limit realize high isolation voltage's reference circuit, solve the less and not enough precision of the linear opto-coupler of current adjustable charger, receive the great technical problem of irradiation influence.

In order to realize the purpose, the utility model adopts the technical scheme as follows:

a reference circuit for realizing high isolation voltage from a primary side to a secondary side comprises a voltage division circuit, an isolation amplification circuit, a comparison amplification circuit, a signal adjusting circuit and a sampling circuit, wherein the output end of the voltage division circuit is connected with the input end of the isolation amplification circuit, the output end of the isolation amplification circuit is connected with the input end of the comparison amplification circuit, the output end of the comparison amplification 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 sampling circuit.

Further, the voltage division circuit comprises a capacitor C1, a resistor R1 and a resistor R2, one end of the capacitor C1 is connected with the primary side control signal end CTR and one end of the resistor R1 respectively, the other end of the resistor R1 is connected with one end of the resistor R2 and the isolation amplifying circuit respectively, and the other end of the capacitor C1 is connected with the other end of the resistor R2 and connected with the primary side ground end PGND.

Furthermore, the isolation amplifying circuit comprises a primary power circuit, an isolation operational amplifier circuit and a secondary power circuit, wherein the primary power circuit is connected with the primary side of the isolation operational amplifier circuit, and the secondary power circuit is connected with the secondary side of the isolation operational amplifier circuit.

Further, the primary power circuit comprises a capacitor C2, one end of the capacitor C2 is connected to the PVCC terminal of the 5V power supply and the isolation operational amplifier circuit, and the other end of the capacitor C2 is connected to the primary ground terminal PGND.

Further, the secondary side power supply circuit comprises a capacitor C4 and a capacitor C5, one end of the capacitor C4 is respectively connected with one end of the capacitor C5, the 3.3V power supply SVCC end and the isolation operational amplifier circuit, and the other end of the capacitor C4 is connected with the other end of the capacitor C5 and is connected with a secondary side grounding end SGND.

Further, the isolation operational amplifier circuit comprises a resistor R3, a resistor R4, an isolation operational amplifier U1, a resistor R8 and a resistor R9, one end of the resistor R3 is connected with a voltage division circuit, the other end of the resistor R3 is connected with a positive input end VINP of the isolation operational amplifier U1, one end of the resistor R4 is connected with a primary side ground end PGND, the other end of the resistor R4 is connected with a negative input end VINN of the isolation operational amplifier U1, a primary side power end VDD1 of the isolation operational amplifier U1 is connected with a primary side power circuit, a secondary side power end VDD2 of the isolation operational amplifier U1 is connected with a secondary side power circuit, a positive output end VOUTP of the isolation operational amplifier U1 is connected with one end of the resistor R8, and a negative output end VOUTN of the isolation operational amplifier U1 is connected with one end of the resistor R9.

Further, the specific column amplifying circuit comprises a filter circuit and an amplifying circuit, the input end of the filter circuit is connected with the isolation amplifying circuit, the output end of the filter circuit is connected with the amplifying circuit, the filter circuit comprises a resistor R10, a resistor R11 and a capacitor C6, one end of the resistor R10 is respectively connected with the resistor R9 and the amplifying circuit, the other end of the resistor R10 is respectively connected with one end of the resistor R11 and one end of the capacitor C6 and is connected with a secondary grounding end SGND, and the other end of the resistor R11 is respectively connected with the other end of the capacitor C6 and the resistor R8.

Further, the amplifying circuit comprises a capacitor C7, a capacitor C8, a resistor R12, a capacitor C9 and an amplifier U15, one end of the capacitor C7 is connected with a secondary ground terminal SGND, the other end of the capacitor C7 is respectively connected with one end of the capacitor C8, one end of the resistor R12 and a negative input terminal of the amplifier U15, the other end of the capacitor C8 is respectively connected with the other end of the resistor R12 and an output terminal of the amplifier U15, one end of the capacitor C9 is connected with a power supply terminal of the amplifier U15, and the other end of the capacitor C9 is connected with the secondary ground terminal SGND.

Further, the signal adjusting circuit comprises a resistor R14, a resistor R15, a capacitor C10 and a voltage reference device U2, one end of the resistor R14 is connected with the output end of the amplifier U15, the other end of the resistor R14 is respectively connected with one end of the resistor R15, one end of the capacitor C10 and a REF pin end of the voltage reference device U2, the other end of the resistor R15 is respectively connected with the other end of the capacitor C10 and the positive input end of the voltage reference device U2, and the reverse input end of the voltage reference device U2 is connected with the sampling circuit.

Further, the sampling circuit comprises a resistor R17 and a resistor R16, one end of the resistor R17 is connected with a REF pin end of the voltage reference device U2, the other end of the resistor R17 is connected with one end of the resistor R16, the connection position is a voltage acquisition point, and the other end of the resistor R16 is connected with a 10V power supply end.

When the voltage of the primary side CTR is 0, the maximum C-REF voltage value can be set by adjusting the resistance values of the U2 peripheral devices R16 and R17, so that the loop is prevented from being in an open loop state, the power circuit is protected, and safety and reliability are realized. The output differential mode signal is small and needs to be amplified in U15 proportion, and the amplified signal adjusts U2, so that C-REF is adjustable.

The utility model discloses owing to adopted above-mentioned technical scheme, following beneficial effect has:

the utility model discloses applied isolation operational amplifier has solved voltage reference control signal on the primary side, and sampling circuit is in the not problem altogether that the secondary side brought, and isolation voltage is up to 5000VDC. The circuit control mode is simple, compared with other isolation modes, the circuit control mode has the advantages of small size and high precision, the circuit control mode has wide application prospect in the occasions with high aerospace power density, and when the voltage of the primary side CTR is 0, the maximum C-REF voltage value can be set by adjusting the resistance values of the U2 peripheral devices R16 and R17, so that the loop can be prevented from being in an open loop state, the power circuit is protected, and safety and reliability are realized.

Drawings

Fig. 1 is a circuit block diagram of the present invention;

fig. 2 is a schematic circuit diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and by referring to preferred embodiments. However, it should be noted that the numerous details set forth in the description are merely intended to provide a thorough understanding of one or more aspects of the invention, even though such aspects of the invention may be practiced without these specific details.

As shown in fig. 1, a reference circuit for realizing high isolation voltage from a primary side to a secondary side includes a voltage dividing circuit, an isolation amplifying circuit, a column comparison amplifying circuit, a signal adjusting circuit and a sampling circuit, wherein an output end of the voltage dividing circuit is connected with an input end of the isolation amplifying circuit, an output end of the isolation amplifying circuit is connected with an input end of the column comparison amplifying circuit, an output end of the column comparison amplifying circuit is connected with an input end of the signal adjusting circuit, and an output end of the signal adjusting circuit is connected with an input end of the sampling circuit. The detailed circuit structure is described below. The control signal is transmitted to the isolation amplifying circuit for isolation amplification after passing through the voltage division circuit. The column amplification circuit performs a second amplification process.

As shown in fig. 2, the reference signal isolation amplifying circuit is composed of C1, R2, R3, R4, C2 and an isolation operational amplifier U1. The adjustable reference voltage circuit consists of an operational amplifier U15, a voltage reference chip U2 and a peripheral resistor-capacitor. The isolation operational amplifier solves the problem of non-common ground caused by the fact that a voltage reference control signal is on the primary side and a sampling circuit is on the secondary side, and isolation voltage is up to 5000VDC. The circuit is specially designed according to the use requirement of a certain user, and is suitable for other circuits needing to realize the isolation reference voltage. The output differential mode signal is small and needs to be amplified in U15 proportion, and the amplified signal adjusts U2, so that C-REF is adjustable. PGND represents the primary side ground, SGND represents the secondary side ground, and both are not at the same ground.

In the embodiment of the utility model, as shown in fig. 2, bleeder circuit includes electric capacity C1, resistance R1 and resistance R2, and electric capacity C1's one end is connected with former limit control signal end CTR and resistance R1's one end respectively, and resistance R1's the other end is connected with resistance R2's one end and isolation amplifier circuit respectively, and electric capacity C1's the other end is connected with resistance R2's the other end to be connected with former limit ground end PGND. In the circuit, CTR is a primary side control signal, and C-REF is a reference voltage of a secondary side sampling circuit. After the CTR voltage is divided by the R1 and the R2, a signal enters the isolation operational amplifier U1.

In the embodiment of the utility model, as shown in fig. 2, keep apart amplifier circuit and include that former limit power supply circuit, isolation fortune put ware circuit and vice limit power supply circuit, former limit power supply circuit and isolation fortune put the former limit of ware circuit and be connected, vice limit power supply circuit and isolation fortune put the vice limit of ware circuit and be connected. The primary side power supply circuit comprises a capacitor C2, one end of the capacitor C2 is respectively connected with a 5V power supply PVCC end and the isolation operational amplifier circuit, and the other end of the capacitor C2 is connected with a primary side ground end PGND. The secondary side power supply circuit comprises a capacitor C4 and a capacitor C5, one end of the capacitor C4 is respectively connected with one end of the capacitor C5, the 3.3V power supply SVCC end and the isolation operational amplifier circuit, and the other end of the capacitor C4 is connected with the other end of the capacitor C5 and is connected with a secondary side grounding end SGND. The isolation operational amplifier circuit comprises a resistor R3, a resistor R4, an isolation operational amplifier U1, a resistor R8 and a resistor R9, one end of the resistor R3 is connected with a voltage division circuit, the other end of the resistor R3 is connected with one end of a positive input end VINP of the isolation operational amplifier U1, which is connected with a primary ground end PGND, the other end of the resistor R4 is connected with a negative input end VINN of the isolation operational amplifier U1, a primary power end VDD1 of the isolation operational amplifier U1 is connected with a primary power circuit, a secondary power end VDD2 of the isolation operational amplifier U1 is connected with a secondary power circuit, a positive output end VOUTP of the isolation operational amplifier U1 is connected with one end of the resistor R8, and a negative output end VOUTN of the isolation operational amplifier U1 is connected with one end of the resistor R9. The signal enters an isolation operational amplifier U1, the isolated differential mode signal is output by a VOUTP pin and a VOUTN pin of the U1, the supply voltage of the secondary side of the U1 is only 3.3V, and the output differential mode signal is small and needs to be amplified in a U15 proportion.

In the embodiment of the utility model, as shown in fig. 2, than arranging amplifier circuit and including filter circuit and amplifier circuit, filter circuit's input and isolation amplifier circuit are connected, the filter circuit output is connected with amplifier circuit, filter circuit includes resistance R10, resistance R11 and electric capacity C6, resistance R10's one end is connected with resistance R9 and amplifier circuit respectively, resistance R10's the other end is connected with resistance R11's one end and electric capacity C6's one end respectively, and be connected with vice limit earthing terminal SGND, resistance R11's the other end is connected with electric capacity C6's the other end and resistance R8 respectively. The amplifying circuit comprises a capacitor C7, a capacitor C8, a resistor R12, a capacitor C9 and an amplifier U15, one end of the capacitor C7 is connected with a secondary grounding terminal SGND, the other end of the capacitor C7 is respectively connected with one end of the capacitor C8, one end of the resistor R12 and a negative input end of the amplifier U15, the other end of the capacitor C8 is respectively connected with the other end of the resistor R12 and an output end of the amplifier U15, one end of the capacitor C9 is connected with a power supply end of the amplifier U15, and the other end of the capacitor C9 is connected with the secondary grounding terminal SGND.

Resistor R12 acts as a feedback resistor, i.e., the feedback of amplifier U15, to better control the amplification. The power supply end of the amplifier U15 is connected with the 10V power supply of the SVCC end for supplying power, and the grounding end of the amplifier U15 is connected with the secondary grounding end SGND.

In the circuit, CTR is a primary side control signal, and C-REF is a reference voltage of a secondary side sampling circuit. After the CTR voltage is divided by R1 and R2, a signal enters an isolation operational amplifier U1, an isolated differential mode signal is output by a VOUTP pin and a VOUTN pin of the U1, the supply voltage of the secondary side of the U1 is only 3.3V, the output differential mode signal is small and needs to be amplified in a U15 proportion, the amplified signal adjusts the U2, and then C-REF (common reference signal) adjustability is achieved

The circuit has another function: when the voltage of the primary side CTR is 0, the maximum C-REF voltage value can be set by adjusting the resistance values of the U2 peripheral devices R16 and R17, so that the loop is prevented from being in an open loop state, the power circuit is protected, and safety and reliability are realized.

In the embodiment of the utility model, as shown in fig. 2, signal conditioning circuit includes resistance R14, resistance R15, electric capacity C10 and voltage reference ware U2, resistance R14's one end is connected with amplifier U15's output, resistance R14's the other end respectively with resistance R15's one end, electric capacity C10's one end and voltage reference ware U2's REF pin end are connected, resistance R15's the other end is connected with electric capacity C10's the other end and voltage reference ware U2's positive input end respectively, voltage reference ware U2's reverse input end and sampling circuit are connected. The resistor R14 serves as a current limiting resistor at the output of the amplifier, and mainly plays a role in limiting current. The resistor R15 and the capacitor C10 mainly form a filter circuit, and the filter circuit is used for filtering the output signal amplified by the amplifier to remove the clutter signal of the output signal.

In the embodiment of the utility model, as shown in fig. 2, sampling circuit includes resistance R17 and resistance R16, and resistance R17's one end is connected with voltage reference ware U2's REF pin end, and resistance R17's the other end is connected with resistance R16's one end, and the junction is the voltage acquisition point, and resistance R16's the other end and 10V power end are connected. The maximum C-REF voltage value is set by adjusting the resistance values of the U2 peripheral devices R16, R17. The 10V power supply connected with the resistor R16 is the same as the power supply of the amplifier U15 and is connected to the same point.

In the circuit, C-REF is a reference voltage signal of a forward input end of an error comparator of the secondary constant-current circuit, a current sampling voltage signal is at a reverse input end of the error comparator, and the larger the C-REF reference voltage is, the larger the output constant current is, otherwise, the smaller the constant current is. The circuit can control the change of the secondary side C-REF by adjusting the size of a primary side control signal CTR, so as to realize the adjustable function of the secondary side constant current, and the principle is as follows: with the increase of the CTR voltage, the output voltage of the isolation operational amplifier U1 is increased, the output voltage of the operational amplifier U15 is also increased, the voltage of the REF pin of the voltage reference U2 (namely the voltage at two ends of the R15) is fixed to be 2.5V, the current flowing through the R17 is reduced after the output voltage of the U15 is increased, and the C-REF voltage is known to be reduced through ohm's law, so that the constant current is reduced.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A reference circuit for achieving high isolation voltage from a primary side to a secondary side, comprising: the sampling circuit comprises a voltage division circuit, an isolation amplifying circuit, a comparison amplifying circuit, a signal adjusting circuit and a sampling circuit, wherein the output end of the voltage division circuit is connected with the input end of the isolation amplifying circuit, the output end of the isolation amplifying circuit is connected with the input end of the comparison amplifying circuit, the output end of the comparison amplifying 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 sampling circuit.

2. The reference circuit of claim 1, wherein the reference circuit is configured to achieve a high isolation voltage from the primary side to the secondary side, and further comprising: the voltage division circuit comprises a capacitor C1, a resistor R1 and a resistor R2, one end of the capacitor C1 is connected with one end of a primary side control signal end CTR and one end of the resistor R1 respectively, the other end of the resistor R1 is connected with one end of the resistor R2 and the isolation amplifying circuit respectively, and the other end of the capacitor C1 is connected with the other end of the resistor R2 and connected with a primary side ground end PGND.

3. The reference circuit of claim 1, wherein the reference circuit is configured to achieve a high isolation voltage from the primary side to the secondary side, and further comprising: the isolation amplifying circuit comprises a primary power circuit, an isolation operational amplifier circuit and a secondary power circuit, wherein the primary power circuit is connected with the primary side of the isolation operational amplifier circuit, and the secondary power circuit is connected with the secondary side of the isolation operational amplifier circuit.

4. The reference circuit of claim 3, wherein the reference circuit comprises a primary side and a secondary side, and wherein: the primary side power circuit comprises a capacitor C2, one end of the capacitor C2 is respectively connected with a 5V power supply PVCC end and the isolation operational amplifier circuit, and the other end of the capacitor C2 is connected with a primary side ground end PGND.

5. The reference circuit of claim 4, wherein the reference circuit comprises a primary side and a secondary side, and wherein: the secondary side power supply circuit comprises a capacitor C4 and a capacitor C5, one end of the capacitor C4 is respectively connected with one end of the capacitor C5, the 3.3V power supply SVCC end and the isolation operational amplifier circuit, and the other end of the capacitor C4 is connected with the other end of the capacitor C5 and is connected with a secondary side grounding end SGND.

6. The reference circuit of claim 5, wherein the reference circuit is configured to achieve a high isolation voltage from the primary side to the secondary side, and further comprising: the isolation operational amplifier circuit comprises a resistor R3, a resistor R4, an isolation operational amplifier U1, a resistor R8 and a resistor R9, one end of the resistor R3 is connected with a voltage division circuit, the other end of the resistor R3 is connected with a positive input end VINP of the isolation operational amplifier U1, one end of the resistor R4 is connected with a primary ground end PGND, the other end of the resistor R4 is connected with a negative input end VINN of the isolation operational amplifier U1, a primary power end VDD1 of the isolation operational amplifier U1 is connected with a primary power circuit, a secondary power end VDD2 of the isolation operational amplifier U1 is connected with a secondary power circuit, a positive output end VOUTP of the isolation operational amplifier U1 is connected with one end of the resistor R8, and a negative output end VOUTN of the isolation operational amplifier U1 is connected with one end of the resistor R9.

7. The reference circuit for achieving high isolation voltage from a primary side to a secondary side as claimed in claim 6, wherein: the specific amplification circuit comprises a filter circuit and an amplification circuit, the input end of the filter circuit is connected with the isolation amplification circuit, the output end of the filter circuit is connected with the amplification circuit, the filter circuit comprises a resistor R10, a resistor R11 and a capacitor C6, one end of the resistor R10 is respectively connected with the resistor R9 and the amplification circuit, the other end of the resistor R10 is respectively connected with one end of the resistor R11 and one end of the capacitor C6 and is connected with a secondary grounding end SGND, and the other end of the resistor R11 is respectively connected with the other end of the capacitor C6 and the resistor R8.

8. The reference circuit of claim 7, wherein the reference circuit is configured to achieve a high isolation voltage from the primary side to the secondary side, and further comprising: the amplifying circuit comprises a capacitor C7, a capacitor C8, a resistor R12, a capacitor C9 and an amplifier U15, one end of the capacitor C7 is connected with a secondary grounding terminal SGND, the other end of the capacitor C7 is respectively connected with one end of the capacitor C8, one end of the resistor R12 and a negative input end of the amplifier U15, the other end of the capacitor C8 is respectively connected with the other end of the resistor R12 and an output end of the amplifier U15, one end of the capacitor C9 is connected with a power supply end of the amplifier U15, and the other end of the capacitor C9 is connected with the secondary grounding terminal SGND.

9. The reference circuit of claim 8, wherein the reference circuit comprises a primary side to a secondary side, and wherein: the signal adjusting circuit comprises a resistor R14, a resistor R15, a capacitor C10 and a voltage reference device U2, one end of the resistor R14 is connected with the output end of the amplifier U15, the other end of the resistor R14 is respectively connected with one end of the resistor R15, one end of the capacitor C10 and the REF pin end of the voltage reference device U2, the other end of the resistor R15 is respectively connected with the other end of the capacitor C10 and the positive input end of the voltage reference device U2, and the reverse input end of the voltage reference device U2 is connected with the sampling circuit.

10. The reference circuit of claim 9, wherein the reference circuit is configured to achieve a high isolation voltage from the primary side to the secondary side, and further comprising: the sampling circuit comprises a resistor R17 and a resistor R16, one end of the resistor R17 is connected with a REF pin end of the voltage reference device U2, the other end of the resistor R17 is connected with one end of the resistor R16, a voltage collecting point is arranged at the connection position, and the other end of the resistor R16 is connected with a 10V power supply end.