CN212992288U

CN212992288U - High-performance isolation amplifier structure based on magnetic field coupling

Info

Publication number: CN212992288U
Application number: CN202020592096.6U
Authority: CN
Inventors: 黄海滨; 蒋赛尖
Original assignee: STEADICHIPS Inc
Current assignee: Hangzhou Sitai Microelectronics Co ltd
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2021-04-16
Anticipated expiration: 2030-04-20

Abstract

The utility model relates to an isolation amplifier technical field specifically is a high performance isolation amplifier structure based on magnetic field coupling, and it can obtain the signal amplification function of higher performance under limited coupling bandwidth restriction, and it includes sending end module, receiving terminal module, magnetic coupling device, the sending end module includes leading enlargies/filtering module, a serial communication port, leading enlargies/filtering module connects N bit Delta Sigma modulator, current source switch group in order, the receiving terminal module is including the enlarged shaping circuit, parallel/serial converter, the low pass filter who arranges in order, the magnetic coupling device corresponds and sets up N +1, and N is the positive integer.

Description

High-performance isolation amplifier structure based on magnetic field coupling

Technical Field

The utility model relates to an isolation amplifier technical field specifically is a high performance isolation amplifier structure based on magnetic field coupling.

Background

In the field of chip applications, it often occurs that the chip is required to perform signal transmission/amplification between two voltage domains, which transmission/amplification must be performed in different power supply systems, and is therefore referred to as an isolation amplifier.

Magnetic field coupling, as a non-electrical signal coupling mode, has the advantages of good spatial isolation, flat coupling bandwidth amplitude response, high semiconductor integration level and the like. However, the response speed of the magnetic sensor (e.g., hall device, magneto-resistive device) integrated on the chip is slow, and the highest response frequency is usually from hundreds of khz to several mhz, which results in a limited bandwidth of the amplifier signal that can be coupled and fails to satisfy the amplification requirement of the broadband signal. On the other hand, in order to reduce the chip cost, the common isolation chip is packaged normally, and cannot shield the external magnetic field interference. In order to couple signals to be transmitted under interference conditions, digital signal coupling is generally adopted, and due to quantization noise naturally existing in digital signals, the transmission of analog signals in this way will certainly further limit the bandwidth of signals to be transmitted.

Because digital signals naturally have stronger anti-interference characteristics than analog signals, magnetic field coupling selects to couple the digital signals, and the existing isolation amplifier is shown in fig. 1 and mainly comprises a preposed amplifying/filtering module 101 and a digital modulator 102 in a certain form at a transmitting end, wherein the digital modulator has the function of converting the analog signals 100 to be transmitted into digital signals 110, and the digital conversion mode can be pulse width modulation or more complex conversion mode; 103 is a current source and switch circuit that converts a voltage signal to a current signal. The current signal generates a magnetic field through the coil 104, and the magnetic sensor 105 senses the magnetic field and outputs a sensed voltage. The receiving end mainly comprises a magnetic sensor induced voltage reading circuit 106, a digital signal processing circuit 107 and an analog filter and driving circuit 108, and in the structure, due to the adoption of digital signal coupling, high-performance analog-digital converter performance is firstly obtained. Unlike a common analog-digital converter, the converted digital signal should be a signal with a small number of bits (reducing the number of coupling devices) and a high frequency (ensuring signal quality by using oversampling); secondly, the digital signal coupled to the receiving end should be easily restored to an analog signal and guarantee a high restoration quality. The existing isolation amplifier cannot meet the requirements.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that current traditional isolation amplifier can't obtain the signal amplification of high performance under the restriction of limited coupling bandwidth, the utility model provides a high performance isolation amplifier structure based on magnetic field coupling, it can obtain the signal amplification function of higher performance under the restriction of limited coupling bandwidth.

The technical scheme is as follows: a high-performance isolation amplifier structure based on magnetic field coupling comprises a sending end module, a receiving end module and a magnetic coupling device, wherein the sending end module comprises a pre-amplifying/filtering module, the high-performance isolation amplifier structure is characterized in that the pre-amplifying/filtering module is sequentially connected with an N-bit Delta-Sigma modulator and a current source switch group, the receiving end module comprises an amplifying and shaping circuit, a parallel/serial converter and a low-pass filter which are sequentially arranged, the number of the magnetic coupling device is N +1, and N is a positive integer.

It is further characterized in that the N-bit Delta Sigma modulator includes at least two integrators and a multi-bit quantizer.

Adopt the utility model discloses afterwards, different with traditional 1 bit digital modulation signal, the utility model discloses a digital modulation signal is the multibit, just means that it can carry more information of treating transmission analog signal, also means simultaneously under the same digital modulation signal frequency (this frequency is less than the frequency upper limit that can be responded to by the magnetic sensor) condition, and multibit digital modulation information represents higher treat transmission analog signal bandwidth and better signal quality, has satisfied the requirement that obtains the signal amplification of higher performance under the restriction of limited coupling bandwidth.

Drawings

FIG. 1 is a prior art schematic;

FIG. 2 is a schematic diagram of the present invention;

FIG. 3 is a schematic diagram of an N-bit Delta-Sigma modulator;

fig. 4 is a schematic diagram of converting 3 bits to 1 bit.

Detailed Description

As shown in fig. 2, a high-performance isolation amplifier structure based on magnetic field coupling includes a sending end module, a receiving end module, and a magnetic coupling device, where the sending end module includes a pre-amplifying/filtering module 201, the pre-amplifying/filtering module 201 is sequentially connected to an N-bit Delta-Sigma modulator 202 and a current source switch group 203, the receiving end module includes an amplifying and shaping circuit 206, a parallel/serial converter 207, and a low-pass filter 208, which are sequentially arranged, and N +1 magnetic coupling devices are correspondingly arranged, where N magnetic coupling devices transmit signals, 1 magnetic coupling device transmits clocks, and N is a positive integer.

After passing through a pre-amplification/filtering module 201, a signal 200 to be transmitted enters an N-bit Delta-Sigma modulator 202, and an analog signal is modulated into a multi-bit high-frequency pulse width modulation discrete signal 210; the signal passes through the current source switch group 203, and the voltage signals are respectively converted into signal groups (N groups of binary signals) in a current form; meanwhile, clock signals are required to be converted into current signals; the current signal groups (including clock signals) flow through N +1 coils 204 of specific shapes to form corresponding magnetic field signals respectively; the modules complete the conversion from the signals to be transmitted to the magnetic field signals;

in the receiving-end module, the magnetic field signal generated at the transmitting end is converted into an electrical signal by the magnetic sensor 205 integrated on the chip, such as a hall device, and the electrical signal is restored to a pulse width modulation signal after passing through the amplifying and shaping circuit 206. These pulse width modulation signals are passed through a parallel/serial converter circuit 207 to form a digital waveform with higher frequency but signal amplitude of only 1 bit, and after unnecessary high frequency signals and quantization noise are filtered by a low pass filter 208, the digital waveform finally restores a low frequency signal 220 to be transmitted and outputs the signal to a chip pin.

The utility model discloses a structure of an N-bit Delta-Sigma modulator 202, which is shown in figure 3; after passing through a system composed of

integrators

301 and 302 and a multi-bit quantizer 303, an analog signal 300 to be transmitted outputs a multi-bit digital modulation signal, where 310 is a frequency domain diagram and 311 is a time domain diagram. As can be seen from 310 and 311, unlike the conventional 1-bit digital modulation signal, the digital modulation signal is multi-bit, which means that it can carry more information of the analog signal to be transmitted, and at the same time means that under the same digital modulation signal frequency (which is lower than the upper limit of the frequency that can be sensed by the magnetic sensor), the multi-bit digital modulation information represents higher bandwidth of the analog signal to be transmitted and better signal quality.

As shown in fig. 4, 3 bits to 1 bit (actual circuit may be any bit to 1 bit); although a part of digital circuits are added in the conversion, the requirement for a high-performance digital-to-analog converter is omitted, the design and the chip complexity can be effectively simplified, and meanwhile, high-quality analog signals are output after passing through a low-pass filter.

Claims

1. A high-performance isolation amplifier structure based on magnetic field coupling comprises a sending end module, a receiving end module and a magnetic coupling device, wherein the sending end module comprises a pre-amplifying/filtering module, the high-performance isolation amplifier structure is characterized in that the pre-amplifying/filtering module is sequentially connected with an N-bit Delta-Sigma modulator and a current source switch group, the receiving end module comprises an amplifying and shaping circuit, a parallel/serial converter and a low-pass filter which are sequentially arranged, the number of the magnetic coupling device is N +1, and N is a positive integer.

2. The magnetic field coupling-based high performance isolated amplifier structure of claim 1, wherein the N-bit Delta Sigma modulator comprises at least two integrators and a multi-bit quantizer.