RU2328014C1 - Magnet-sensitive integral circuit - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: magnet-sensitive integral circuit is related to the field of electronic detectors of magnetic field, and more precisely, to magnet-sensitive integral circuits (MSIC). Fields of MSIC application are autoelectrics, automatics and robotics, measuring equipment, systems of navigation and orientation, safety systems. Problem put by is achieved in design of MSIC, which contains primary transducer of magnet field into electric signal that is controlled by electric field and is made with the possibility of functioning on the basis of Hall effect, differential selective amplifier and two generators, novelty of which consists in the fact that as primary transducer, transducer is used that contains two control field gates, to every of which one of the generators in directly connected, at that outlet of generators output is connected to amplifier inputs.

EFFECT: reduced level of commutation impediments and parasite noises.

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Description

The invention relates to the field of electronic magnetic field sensors, and more particularly to magnetically sensitive integrated circuits (MCHIS). Fields of application of the Ministry of Emergencies - auto electronics, automation and robotics, measuring equipment, navigation and orientation systems, security systems.

It is known that magnetically sensitive integrated circuits are the main elements of various monitoring and control devices. In the design of the MCHIS, primary converters of the magnetic field are integrated into the electric signal and electronic components, which provide registration and processing of the useful signal.

Typically, in such MCHIS direct amplification of the signal of the primary converter is used with the registration of the output signal by voltage or current (Baranochnikov M.L. Micromagnetoelectronics, ed. DMK, M., 2001, v. 1, p. 541).

The disadvantage of such an MCM is the limited threshold sensitivity that does not allow the detection of weak magnetic fields. This disadvantage can be overcome in the MCHR with frequency modulation of the magnetically induced signal.

Closest to the present invention, the technical solution adopted for the prototype is MCHIS (Cooper AR, Brignell IE A magnetic field transducer with frequency modulated output. J. Phys. E: Sci. Instr., 1984, v.17, p., 627 .), where as a primary transducer of a magnetic field into an electric signal, configured to function on the basis of the Hall effect, a two-line field-effect transistor is used. MCHIS also contains two amplifiers and two generators producing the same frequency. Two chains of the form of a drain of a field effect transistor are realized in the MCHIS — the input of the amplifier — the output of the amplifier — the generator — the output of the MCHIS. The generators frequency modulate the amplified signals from the drains of the transistor. When using a selective recording device tuned to the generation frequency, an increase in the signal-to-noise ratio of the MSMC and, therefore, the possibility of improving its threshold sensitivity is provided.

The disadvantage of this solution is the concomitant modulation of the appearance of switching noise and spurious noise, limiting the threshold sensitivity.

The problem to which this invention is directed, is the creation of MCHIS, characterized by high threshold sensitivity.

The technical result obtained in solving this problem is to obtain an MChS with a reduced level of switching noise and spurious noise.

The problem is achieved in the design of the MChS, containing a primary field-controlled converter of the magnetic field into an electric signal, configured to function on the basis of the Hall effect, a differential selective amplifier and two generators, the novelty of which is that a converter containing two control field shutters, to each of which one of the generators is directly connected, and the output of the generators is sub It is connected to the inputs of the amplifier.

In order to avoid excessively high requirements on the parameters of the amplifier, generators are used as generators that can generate signals of different frequencies, and as an amplifier, an amplifier is configured to be tuned to a frequency whose value is determined by the frequency difference of both generators.

The difference in the operating frequencies of the generators, generally speaking, is not a critical parameter. It is practically convenient if the corresponding frequencies differ 1.5-3 times.

As a primary magnetic field transducer, a split-drain field effect transistor formed on the basis of a semiconductor (for example, Si) and containing a source, a channel, two sinks, a gate insulator on the surface of the semiconductor above the channel and a gate located on the surface of the gate dielectric can be used, moreover the sensor further comprises another gate, so that both gates are located one after the other on the gate dielectric.

Also, as a primary magnetic field transducer, you can use the field Hall sensor (Mordkovich VN et al. Field Hall sensor - a new type of magnetic field transducer. Sensors and systems, 2003, No. 7, p.33-37), having a vertical double-gate control system.

The proposed design MCHIS allows you to reduce the level of switching interference and spurious noise.

The invention is further explained in more detail with reference to the accompanying drawings, which depict:

Figure 1 shows a schematic diagram of the MChS according to the invention.

Figure 2 is a diagram of a double-gate control field system of a two-line field-effect transistor, A is a cross section. B - top view.

Figure 3 is a diagram of a double-gate control field system of a field Hall sensor (cross section).

 MCHIS contains a primary magnetic field converter 1, having two control field shutters 2 and 3, two generators 4 and 5, one of which is connected to the gate 2, and the other to the gate 3, and a selective differential amplifier 6, to the inputs of which the output signals generators 4 and 5 (figure 1).

As a primary converter, a field-effect transistor formed on the basis of a semiconductor 7 (for example, Si) and containing a source region 8, a channel 9, a drain 10, a gate insulator 11 on the surface of the semiconductor 7, and two gates 12 and 13 located one after another can be used on the surface of the gate dielectric 7 above the channel 9 (figa). Moreover, the drain region 10 is split into two parts of equal size (Fig.2B).

Also, a Hall sensor can be used as a primary converter. It is formed in a Si 14 layer of a silicon on an insulator structure, which also consists of a layer of a hidden dielectric 15 and a silicon substrate 16 (Fig. 3). A dielectric film 17 with a gate electrode 18 located on it is formed on the surface of the Si 14 layer. The dielectric 17 and the gate 18 form the first field system that controls the magnitude and shape of the current flowing through the silicon layer 14. The second control field system is formed by a hidden dielectric 15 and a silicon substrate 16 with the gate electrode 19 located on it. Signal generators 2 and 3 are connected to the electrodes 18 and 19, respectively.

MCHIS works as follows. Generators produce signals of a certain frequency, and the frequency values can either coincide or differ from each other. Due to this, modulation of the current flowing through the channel of the primary converter and, consequently, the output signal of the primary converter occurs, and the modulation frequency is determined by the frequencies of the generators. The greatest effect is observed when the operating frequencies of the generators are different. The differential selective amplifier is tuned to the modulation frequency, due to which it provides not only signal amplification, but also an increase in the signal-to-noise ratio. Moreover, the specified modulation depth does not exceed 90%, which virtually eliminates the appearance of switching noise. As a result, the threshold sensitivity of the MCM is improved by orders of magnitude.

The table shows the values of the noise level of the MChS using a field Hall sensor as a primary magnetic field transducer, confirms the advantages, but does not limit the use of the proposed design of the MChS.

Table Channel current modulation frequency, Hz Noise level MCHIS (rel. Units) The operating frequencies of the generators match The operating frequencies of the generators differ by 2 times 0 thirty - one hundred 3 ... 4 0.5 ... 0.8 1000 1 ... 1,2 0.15 ... 0.25 10,000 0.13 ... 0.16 0.02 ... 0.025 Note: at a bandwidth of 1 Hz.

As can be seen from the table, the proposed design MCHIS allows you to reduce the level of switching interference and spurious noise.

Claims (4)

1. Magnetosensitive integrated circuit containing an electric field-controlled primary transducer of a magnetic field into an electric signal configured to function on the basis of the Hall effect, a differential selective amplifier and two generators, characterized in that a transducer containing two control field shutters is used as the primary transducer , each of which is directly connected to one of the generators, and the output of the generators is connected to the inputs of the amplifier . 2. The magnetosensitive integrated circuit according to claim 1, characterized in that the generators use oscillators capable of generating signals of different frequencies, and the amplifier is an amplifier configured to be tuned to a frequency whose value is determined by the frequency difference of both generators. 3. The magnetosensitive integrated circuit according to claim 1, characterized in that a split-drain field effect transistor formed on the basis of a semiconductor (for example, silicon) and containing a source region, a channel, two drains, a gate insulator on the surface is used as the primary magnetic field converter a semiconductor above the channel and a gate located on the surface of the gate dielectric, the sensor further comprising another gate, so that both gates are located on the gate dielectric g other. 4. The magnetosensitive integrated circuit according to claim 1, characterized in that as the primary transducer of the magnetic field using a field Hall sensor having a vertical two-gate control system.

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