Amplifier for isolation occasion

Abstract

The invention discloses an amplifier for an isolation occasion. The amplifier comprises capacitors C1 to C4, clock-controlled switches S1 to S4 and a main operational amplifier OP1, the isolation and amplification problems in a signal sampling occasion needing isolation and amplification are innovated, the designed isolation and amplification circuit can be suitable for the application occasion that the voltage range where an input signal is located and the voltage range where an output signal is located are inconsistent, and certain expansibility is achieved according to different isolation voltages withstood by a capacitor. For an isolation amplification application occasion, input and output of a signal can be transmitted across a voltage domain in a simple mode, the circuit is simple and adapts to the current process manufacturing level, and different from a traditional isolation amplification scheme in which complex signal modulation and transmission are needed, the intermediate complex modulation and transmission process is omitted, and the cost is reduced. The design is simplified, and the reliability of the circuit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to an amplifier used in isolation situations. Background Art

[0002] Isolation op amps are widely used in signal acquisition and current measurement applications. Traditional isolation op amps need to convert the signal from analog to digital first, and then convert the digital into analog after passing through isolation digital transmission technology. The process involves relatively complex signal modulation and demodulation technology, and the circuit complexity is relatively high. Summary of the invention

[0003] The object of the present invention is to provide an amplifier for use in isolation situations to solve the problems in the background technology.

[0004] In order to solve the above technical problems, the present invention provides an amplifier for use in isolation occasions, comprising: capacitors C1-C4, clock-controlled switches S1-S4, and a main operational amplifier OP1;

[0005] The first end of the capacitor C1 is connected to the static contact of the clock-controlled switch S1, the first moving contact of the clock-controlled switch S1 is connected to the input signal VHi, and the second moving contact is connected to the input signal VLo; the first end of the capacitor C2 is connected to the static contact of the clock-controlled switch S2, the first moving contact of the clock-controlled switch S2 is connected to the input signal VHi, and the second moving contact is connected to the input signal VLo;

[0006] The second end of the capacitor C1 is connected to the static contact of the clock-controlled switch S3, the first static contact of the clock-controlled switch S3 is simultaneously connected to the first input end of the main operational amplifier OP1 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first output end of the main operational amplifier OP1, and the first output end of the main operational amplifier OP1 outputs a signal VoutA; the second static contact of the clock-controlled switch S3 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1; the second end of the capacitor C2 is connected to the static contact of the clock-controlled switch S4, the first static contact of the clock-controlled switch S4 is simultaneously connected to the second input end of the main operational amplifier OP1 and the first end of the capacitor C4, the second end of the capacitor C4 is connected to the second output end of the main operational amplifier OP1, and the second output end of the main operational amplifier OP1 outputs a signal VoutB; the second static contact of the clock-controlled switch S4 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1.

[0007] In one implementation, the capacitors C1 and C2 are high-voltage capacitors, and the capacitors C3 and C4 are low-voltage high-precision capacitors.

[0008] In one implementation, the power supply and ground of the control signals of the clocked switches S1 and S2 are in the same voltage domain as the input voltage domain, and the power supply and ground of the control signals of the clocked switches S3 and S4 are in the same voltage domain as the output voltage domain.

[0009] In one implementation, the input signals VHi and VLo operate in an input voltage domain, and the output signals VoutA and VoutB and the common mode voltage input VCOM of the main operational amplifier OP1 operate in an output voltage domain.

[0010] The present invention provides an amplifier for use in isolation occasions. For isolation amplification applications, the present invention can transmit the input and output of signals across voltage domains in a simple manner. The circuit is simple and adapted to the current process manufacturing level. Unlike traditional isolation amplification that requires complex signal modulation and transmission schemes, the present invention omits the complex modulation and transmission process in the middle, simplifies the design, and improves the reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of an amplifier used in isolation occasions provided by the present invention.

[0012] Figure 2 This is a schematic diagram of the clock drive waveform of the clock-controlled switch S1 / 2 / 3 / 4.

[0013] Figure 3 It is a schematic diagram of the switch position at moments AA and AA'. DETAILED DESCRIPTION

[0014] The following is a further detailed description of an amplifier for isolation occasions proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0015] The present invention provides an amplifier for use in isolation situations, the overall circuit structure of which is as follows Figure 1 As shown, VHi and VLo are input signals, VoutA and VoutB are output signals, and the circuit has differential amplification and isolation amplification capabilities. The principle is as follows:

[0016] The overall circuit consists of high-voltage capacitors C1 and C2, low-voltage high-precision capacitors C3 and C4, clock-controlled switches S1 / 2 / 3 / 4, and the main operational amplifier OP1; the external input signal includes VHi and VLo input signals working in the input voltage domain, and VoutA, VoutB and VCOM signals working in the output voltage domain. When working, VHi and VLo are connected to the collected signals, VoutA and VoutB are the amplified signals, and VCOM is the common-mode voltage input of the main operational amplifier OP1.

[0017] The first end of capacitor C1 is connected to the static contact of clocked switch S1, the first moving contact of clocked switch S1 is connected to input signal VHi, and the second moving contact is connected to input signal VLo; the first end of capacitor C2 is connected to the static contact of clocked switch S2, the first moving contact of clocked switch S2 is connected to input signal VHi, and the second moving contact is connected to input signal VLo. The second end of the capacitor C1 is connected to the static contact of the clock-controlled switch S3, the first static contact of the clock-controlled switch S3 is simultaneously connected to the first input end of the main operational amplifier OP1 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first output end of the main operational amplifier OP1, and the first output end of the main operational amplifier OP1 outputs a signal VoutA; the second static contact of the clock-controlled switch S3 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1; the second end of the capacitor C2 is connected to the static contact of the clock-controlled switch S4, the first static contact of the clock-controlled switch S4 is simultaneously connected to the second input end of the main operational amplifier OP1 and the first end of the capacitor C4, the second end of the capacitor C4 is connected to the second output end of the main operational amplifier OP1, and the second output end of the main operational amplifier OP1 outputs a signal VoutB; the second static contact of the clock-controlled switch S4 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1.

[0018] like Figure 2 As shown, when the clock starts to oscillate, at time AA, the clock-controlled switch S1 is connected to the VHi voltage to charge the capacitor C1, and the other end of the capacitor C1 is connected to the VCOM voltage at this time, and finally the capacitor C1 is charged to the VHi-VCOM voltage; correspondingly, at this time, for the clock-controlled switch S2 side, the capacitor C2 will be charged to the VLo-VCOM voltage;

[0019] After the AA moment, at the AA' moment, all clock-controlled switches will change positions, such as Figure 3 As shown. From AA to AA', due to the switching of the clock-controlled switch, a current of (VHi-VLo) / C1 is introduced into the input of the main operational amplifier OP1. This current flows into the high-precision integral capacitors C3 and C4 and is output to VoutA and VoutB. The final voltage of VoutA-VoutB is 2*(VHi-VLo)*C3 / C1, thus achieving the purpose of signal amplification. Due to the existence of the isolation capacitors C1 / C2, the input and output voltage domains can be grounded separately.

[0020] It should be noted here that the power supply and ground of the control signals of the clocked switches S1 and S2 need to be in the same voltage domain as the input, and the clocked switches S3 and S4 are in the same voltage domain as the output. The isolation voltage depends on the withstand voltage of capacitors C1 and C2, and different manufacturing processes will have different isolation voltage levels.

[0021] The present invention innovates the isolation amplification problem encountered in signal sampling situations that require isolation amplification. The designed isolation amplification circuit can be applicable to application situations where the voltage range of the input signal and the voltage range of the output signal are inconsistent, and has certain scalability according to the different isolation voltages of the capacitor withstand voltage.

[0022] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An amplifier for use in isolation applications, characterized in that: include: Capacitors C1~C4, clock-controlled switches S1~S4, main operational amplifier OP1; The first end of the capacitor C1 is connected to the static contact of the clock-controlled switch S1, the first moving contact of the clock-controlled switch S1 is connected to the input signal VHi, and the second moving contact is connected to the input signal VLo; the first end of the capacitor C2 is connected to the static contact of the clock-controlled switch S2, the first moving contact of the clock-controlled switch S2 is connected to the input signal VHi, and the second moving contact is connected to the input signal VLo; The second end of the capacitor C1 is connected to the static contact of the clock-controlled switch S3, the first static contact of the clock-controlled switch S3 is simultaneously connected to the first input end of the main operational amplifier OP1 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first output end of the main operational amplifier OP1, and the first output end of the main operational amplifier OP1 outputs a signal VoutA; the second static contact of the clock-controlled switch S3 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1; the second end of the capacitor C2 is connected to the static contact of the clock-controlled switch S4, the first static contact of the clock-controlled switch S4 is simultaneously connected to the second input end of the main operational amplifier OP1 and the first end of the capacitor C4, the second end of the capacitor C4 is connected to the second output end of the main operational amplifier OP1, and the second output end of the main operational amplifier OP1 outputs a signal VoutB; the second static contact of the clock-controlled switch S4 is connected to the common-mode voltage input VCOM of the main operational amplifier OP1.

2. The amplifier for use in isolation applications as claimed in claim 1, characterized in that: The capacitors C1 and C2 are high-voltage capacitors, and the capacitors C3 and C4 are low-voltage high-precision capacitors.

3. The amplifier for use in isolation applications as claimed in claim 1, characterized in that: The power supply and ground of the control signals of the clock-controlled switches S1 and S2 are in the same voltage domain as the input voltage domain, and the power supply and ground of the control signals of the clock-controlled switches S3 and S4 are in the same voltage domain as the output voltage domain.

4. The amplifier for use in isolation applications as claimed in claim 1, characterized in that: The input signals VHi and VLo operate in an input voltage domain, and the output signals VoutA and VoutB and the common mode voltage input VCOM of the main operational amplifier OP1 operate in an output voltage domain.

Images