CN115940851A - A high-precision broadband three-port isolation amplifier based on hybrid technology - Google Patents

Abstract

The invention discloses a high-precision broadband three-port isolation amplifier based on a hybrid process, which is respectively connected with two ends of primary coils of a power transformer T2 and a power transformer T3 through the output end of an oscillator; two ends of a secondary coil of the power transformer T2 are connected with the input end of an input power supply, and two ends of a secondary coil of the power transformer T3 are connected with the input end of an output power supply; the output end of the modulator is connected with two ends of a primary coil of the signal transformer T1, the input end of the demodulator is connected with two ends of a secondary coil of the signal transformer T1, and the isolation amplifier has a three-port isolation design, so that the input, the output and the power supply have independence, and the isolation of three ports is completed simultaneously; the signal is completely isolated from the power supply through the coupling of the transformer in the circuit, and the isolated transmission of the signal is completed, so that the isolation of the input and output signals is realized, and the isolation of the input and output signals from the power supply is also realized.

Description

A high-precision broadband three-port isolation amplifier based on hybrid technology

technical field

The invention relates to the technical field of isolation amplifiers, in particular to a high-precision broadband three-port isolation amplifier based on a hybrid process.

Background technique

In the signal processing system, it is often necessary to amplify the signal. In order to avoid the mutual interference of the signal and reduce the impact of the common mode signal on the accuracy of the signal acquisition, an isolation amplifier is required for signal transmission to avoid direct connection to the high-voltage system. An isolation amplifier is an amplifier that realizes electrical isolation between the input circuit and the output circuit. Generally, a transformer or an optical coupling is used to transmit signals, and it can be widely used in industrial control, signal measurement, medical equipment and other fields. The transfer characteristics of optocouplers are sensitive to temperature and require temperature compensation for proper operation. The transformer coupling method has better temperature characteristics than optocouplers, and the isolation voltage can be as high as thousands of volts.

Electronic instruments in military fields such as aviation and aerospace use a large number of isolation amplifiers to obtain the required measurement data. At present, most isolation amplifiers use plastic-encapsulated devices, the quality level is usually industrial grade, and the operating temperature range is -40°C to 85°C, which cannot meet the operating temperature requirements of -55°C to 125°C in the military industry. Moreover, most isolation amplifiers only isolate the input and output signals, and fail to achieve isolation from the power supply.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a high-precision broadband three-port isolation amplifier based on a hybrid process. The isolation amplifier completely isolates the signal from the power supply through the transformer coupling inside the circuit, and completes the isolated transmission of the signal, not only The signal isolation of input and output is realized, and the isolation from the power supply is also realized.

The present invention is achieved through the following technical solutions:

A high-precision broadband three-port isolation amplifier based on a hybrid process, including an input amplifier, a modulator, a signal transformer T1, a demodulator, a power transformer T2, a power transformer T3, an oscillator and an output amplifier;

The output terminals of the oscillator are respectively connected to the two ends of the primary coils of the power transformer T2 and the power transformer T3; the two ends of the secondary coils of the power transformer T2 are connected to the input terminals of the input power supply, and the secondary The two ends of the primary coil are connected to the input of the output power supply; the input of the input amplifier is connected to the input signal, the output of the input amplifier is connected to the modulator, and the output of the modulator is connected to the two primary coils of the signal transformer T1 terminal, the input terminal of the demodulator is connected to both ends of the secondary coil of the signal transformer T1; the output terminal of the demodulator is connected to the input terminal of the output amplifier;

Preferably, the output terminals of the input power supply are respectively connected to the input amplifier and the modulator; the output terminals of the output power supply are connected to the output amplifier and the demodulator.

Preferably, the metal shell insulator of the isolation amplifier is a ceramic insulator.

Preferably, the framework of the signal transformer T1, the power transformer T2 and the power transformer T3 is a three-layer structure.

Preferably, the primary coils of the signal transformer T1, the power transformer T2 and the power transformer T3 are isolated from the secondary coils by an isolation strip in the middle of the frame, and the thickness of the isolation strip is 0.7mm.

Preferably, the surfaces of the enameled wires of the signal transformer T1, the power transformer T2 and the power transformer T3 are coated with insulating materials.

Preferably, the antistatic capability of the three-port isolation amplifier is ≥4000V.

Preferably, the circuit isolation voltage of the three-port isolation amplifier is ≥3500VDC and ≥2500VAC.

Preferably, the three-port isolation amplifier is assembled with a bare chip and packaged with a metal hermetic package.

Preferably, the operating temperature range of the three-port isolation amplifier is -55°C to +125°C, and the storage temperature range is -65°C to +150°C.

Compared with the prior art, the present invention has the following beneficial technical effects:

The invention provides a high-precision broadband three-port isolation amplifier based on a hybrid process. Through the combination of the signal transformer T1, the power transformer T2 and the power transformer T3, the isolation amplifier has a three-port isolation design, so that the input, output and power supply are independent. At the same time, the isolation of the three ports is completed; the isolation amplifier completely isolates the signal from the power supply through the transformer coupling inside the circuit, and completes the isolated transmission of the signal, which not only realizes the isolation of input and output signals, but also realizes the isolation from the power supply. amplifier;

Furthermore, the isolation amplifier uses a single +15V power supply, no external DC/DC converter is required, and the three-port design allows it to be used as an input and output isolator in single-channel or multiple-channel applications, and it remains stable under continuous common-mode stress. Can maintain high performance.

Furthermore, this isolation amplifier is based on hybrid integrated circuit technology, and adopts bare chip assembly and metal hermetic packaging. The working temperature range is -55°C to +125°C, and the storage temperature range is -65°C to +150°C;

Furthermore, the isolated power supply is generated inside the circuit, and the input and output parts generate an isolated voltage of ±15V and a current of ≥±5mA. In addition to supplying power to the internal amplifier, modulation circuit, and demodulation circuit of the circuit, it can also be used as a peripheral circuit (such as sensors, floating signals, etc.) regulation, preamplifier) power supply;

Further, the isolation strength of the circuit is high, and the isolation voltage meets the requirements of 3500V _DC and 2500V _AC ; the bandwidth can reach more than 22kHz; the antistatic ability is ≥4000V; the gain accuracy of the circuit is high, the gain error is ≤±1%, the gain drift is low, and the temperature coefficient Less than 50×10 ^-6 /°C.

Description of drawings

Fig. 1 is the circuit block diagram of three-port isolation amplifier of the present invention;

Fig. 2 is the shell outline drawing of three-port isolation amplifier of the present invention;

Fig. 3 is the lead-out arrangement diagram of the shell of three-port isolation amplifier of the present invention;

Fig. 4 is a circuit application schematic diagram of the three-port isolation amplifier of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

A high-precision broadband three-port isolation amplifier based on a mixed process, including an input power supply, a modulator, a signal transformer (T1), an output power supply, a demodulator, a power transformer (T2, T3), and an oscillator.

The output terminals of the oscillator are respectively connected to the two ends of the primary coils of the power transformer T2 and the power transformer T3; the two ends of the secondary coils of the power transformer T2 are connected to the input terminals of the input power supply, and the secondary The two ends of the primary coil are connected to the input of the output power supply; the input of the input amplifier is connected to the input signal, the output of the input amplifier is connected to the modulator, and the output of the modulator is connected to the two primary coils of the signal transformer T1 terminal, the input terminal of the demodulator is connected to both ends of the secondary coil of the signal transformer T1; the output terminal of the demodulator is connected to the input terminal of the output amplifier; preferably, the output terminals of the input power supply are respectively connected to the input amplifier and a modulator; the output end of the output power supply is connected to an output amplifier and a demodulator.

Based on the hybrid integrated circuit technology, it adopts bare chip assembly and metal hermetic packaging, with an operating temperature range of -55°C to +125°C and a storage temperature range of -65°C to +150°C;

(1) Three-port design: The circuit has a three-port isolation design, which makes the input, output and power supply independent, and completes the isolation of the three ports at the same time;

(2) Isolated power supply design: the input and output parts generate isolation voltage ±15V, current ≥±5mA, in addition to supplying power to the circuit internal amplifier, modulation circuit and demodulation circuit, it can also be used as peripheral circuit (such as sensor, floating signal adjustment) , preamplifier) power supply;

(3) High isolation strength: the isolation voltage meets the requirements of 3500V _DC and 2500V _AC , and the metal shell insulator adopts ceramic insulators;

(4) Antistatic ability ≥ 4000V;

(5) High precision gain: gain error ≤±1%, low gain drift, temperature coefficient less than 50×10 ^-6 /°C.

The input power is used as the power input part of the circuit.

The function of the modulator is to add the input low-frequency signal to the high-frequency oscillating signal, and couple it to the output side through the transformer. Specific working process: The carrier signal is coupled to the secondary side through the T2 transformer, and the coupled signal (50kHz square wave signal) controls the on and off of the analog switch to modulate the input sine wave signal. The sinusoidal signal modulated by the 50kHz square wave signal is coupled to the secondary side through the signal transformer T1. This process completes the modulation and transmission of the sinusoidal signal.

The signal transformer (T1) couples the modulated signal to the output terminal for demodulation and restoration.

The output power supply described is: the isolated power supply circuit is to couple the oscillating signal generated by the oscillator to the secondary side of the input transformer and the output transformer through the transformer, and then perform half-wave rectification and filtering to output ±15V isolated power supply, resulting in ±15V isolated The power supply can output a driving current of 5mA.

The demodulator restores the original modulation signal from the amplitude-controlled high-frequency carrier signal. An analog switch is used to detect and demodulate the modulated signal. The demodulated waveform contains 50kHz high-frequency components, which are filtered by a third-order low-pass filter to restore the input signal.

The power transformers (T2, T3) are in the isolation amplifier, and the power transformers couple the carrier signal to the input terminal, perform rectification and filtering, and provide positive and negative working voltages to the input circuit.

The oscillator generates a 50kHz oscillating signal, and the oscillator has two functions in the circuit, one is to provide power to the front-stage circuit through a transformer; the other is to serve as a carrier signal for signal modulation and demodulation.

The isolation amplifier completely isolates the signal from the power supply through the transformer coupling inside the circuit, and completes the isolated transmission of the signal. The circuit uses a single +15V power supply without the need for an external DC/DC converter. The three-port design allows it to be used as an input and output isolator in single or multiple applications, and remains high under continuous common-mode stress. performance.

The metal shell insulator of the isolation amplifier adopts ceramic insulators; the transformer skeleton has a three-layer structure, and the primary and secondary are separated by a 0.7mm thick isolation belt in the middle of the skeleton; the surface of the transformer enameled wire is coated with insulating materials to improve the isolation strength of the transformer. Through the above design, the circuit isolation voltage is ≥3500V _DC and ≥2500V _AC .

The outline diagram of the circuit is shown in Figure 2, and Table 1 is the product outline dimension table.

Table 1 Product Dimensions in mm

Specifically, as shown in Figure 3, the terminal arrangement diagram (top view) of the isolation amplifier, the pin functions of the isolation amplifier are as follows:

Table 2 lead-out arrangement list

This isolation amplifier can be widely used in multi-channel data acquisition, high voltage instrumentation amplifier, processing signal isolation, current short circuit measurement and other fields. Figure 4 shows the typical application of the isolation amplifier in the VI converter. This circuit can convert the 0V to 10V input voltage into an isolated 4 to 20mA output current. When the 0-10V input voltage is added to the same-phase terminal of the input amplifier of the circuit, a proportional voltage is obtained at the output terminal of the isolation amplifier, that is, 0-10V. In the following output circuit, by properly adjusting the potentiometer, the input voltage (0~10V) can be converted into the output current (4~20mA) through the loop load R _LOAD .

This isolation amplifier is based on hybrid integrated circuit technology, and adopts bare chip assembly and metal hermetic packaging. , The output and power supply are independent, and the isolation of the three ports is completed at the same time; the isolated power supply is generated inside the circuit, the input and output parts generate an isolation voltage of ±15V, and a current of ≥±5mA, except for power supply to the internal amplifier, modulation circuit, and demodulation circuit of the circuit. In addition, it can also be used as a power supply for peripheral circuits (such as sensors, floating signal conditioning, and preamplifiers); the circuit isolation strength is high, and the isolation voltage meets the requirements of 3500V _DC and 2500V _AC ; the bandwidth can reach more than 22kHz; antistatic ability≥ 4000V; the circuit has high gain precision, gain error ≤±1%, low gain drift, and temperature coefficient less than 50×10 ^-6 /°C.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form; all those skilled in the art can smoothly implement the present invention as shown in the attached drawings and the above descriptions. However, any equivalent change, modification and evolution made by those skilled in the art without departing from the scope of the technical solution of the present invention by utilizing the technical content disclosed above are all equivalent implementations of the present invention Example; at the same time, all changes, modifications and evolutions made to the above embodiments according to the substantive technology of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims (10)

1. A high-precision broadband three-port isolation amplifier based on a hybrid process is characterized by comprising an input amplifier, a modulator, a signal transformer T1, a demodulator, a power transformer T2, a power transformer T3, an oscillator and an output amplifier;

the output end of the oscillator is respectively connected with two ends of primary coils of a power transformer T2 and a power transformer T3; two ends of a secondary coil of the power transformer T2 are connected with the input end of an input power supply, and two ends of a secondary coil of the power transformer T3 are connected with the input end of an output power supply; the input end of the input amplifier is connected with an input signal, the output end of the input amplifier is connected with a modulator, the output end of the modulator is connected with two ends of a primary coil of a signal transformer T1, and the input end of the demodulator is connected with two ends of a secondary coil of the signal transformer T1; and the output end of the demodulator is connected with the input end of the output amplifier.

2. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the output end of the input power supply is connected with the input amplifier and the modulator respectively; and the output end of the output power supply is connected with the output amplifier and the demodulator.

3. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the metal housing insulator of the isolation amplifier is a ceramic insulator.

4. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the skeletons of the signal transformer T1, the power transformer T2 and the power transformer T3 are of a three-layer structure.

5. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 4, wherein the primary coils and the secondary coils of the signal transformer T1, the power transformer T2 and the power transformer T3 are isolated by an isolation strip in the middle of a framework, and the thickness of the isolation strip is 0.7mm.

6. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the enameled wires of the signal transformer T1, the power transformer T2 and the power transformer T3 are coated with an insulating material.

7. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the antistatic capability of the three-port isolation amplifier is not less than 4000V.

8. The high-precision broadband three-port isolation amplifier based on hybrid process as claimed in claim 1, wherein the circuit isolation voltage of the three-port isolation amplifier is not less than 3500V _DC And is more than or equal to 2500V _AC 。

9. The hybrid process-based high-precision broadband three-port isolation amplifier according to claim 1, wherein the three-port isolation amplifier is assembled by using bare chips and packaged by using metal full-sealing.

10. The high-precision broadband three-port isolation amplifier based on the hybrid process as claimed in claim 1, wherein the operating temperature range of the three-port isolation amplifier is-55 ℃ to +125 ℃, and the storage temperature range is-65 ℃ to +150 ℃.

Images