RU2453947C2 - Integrated gradient magnetic transistorised sensor - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: invention relates to semiconducting electronics. The invention deals with the integrated gradient magnetic transistorised sensor, which contains two sensor elements, two amplifiers implemented as two current mirrors based on MOS transistors, and comparison circuit with two inputs. The sensor elements with amplifiers are realised as integral current magnetic sensors based on bipolar magnetic transistors located at the fixed distance from each other so that the gradient of magnetic field distribution by sensors signals difference may be measured. Each of the specified sensors is coupled with the input of related CMOS inverter through the current mirror fulfilling loading function and a current mirror output. The CMOS inverter conditions signals levels from current magnetic sensors and input voltages on the corresponding inputs of comparison circuit containing RS trigger and output cascade and one of RS trigger outputs is coupled with output CMOS cascade.

EFFECT: simplified implementation of design and engineering for sensor measuring gradient of magnetic field.

4 cl, 7 dwg

Description

The present invention relates to semiconductor electronics, semiconductor devices containing components that use galvanomagnetic effects to measure the gradient of the magnetic field.

Semiconductor sensors of magnitude and direction of the magnetic field are used in integrated microsystems due to the possibility of combining them with other components of microsystems using microelectronics methods and the creation of microminiature devices for monitoring and control in automated complexes for various purposes [1]. In brushless DC motors, the magnetic field of the rotor, consisting of several permanent magnets, is monitored. The moment of passage of the edge of the magnet past the magnetic sensor must be fixed for the subsequent inclusion of current in the stator windings.

A large number of magnetically controlled microchips have been developed, for example, with Hall sensors. In industrial bipolar integrated circuits using a single Hall sensor, for example, SS41 (Honeywell) (integrated rotor position sensor) with a supply voltage of 4.5-24 V, a consumption current of 15 mA, the on-time is 1.5 μs with a magnetic induction of 15 mT, shutdown time - 1 μs with magnetic induction minus 14 mT, operating frequency - not higher than 100 kHz. Some applications require higher operating frequencies and shorter on and off times.

The company Allegro MicroSystems produces dual-sensor magnetically controlled microchips type A3046 (A3056, A3058) with a distance between Hall sensors of 2.23 mm. This distance is relatively large and is characteristic of the distance between the rotor magnets, and not for the distribution of the field at the edge of one magnet. The signal from the two sensors goes with a shift, which is determined by the location of the sensors, the size of the magnets and the speed of rotation. With a supply voltage of 4.5-24 V, a consumption current of 7-14 mA, the on-time is 1.5 μs with a magnetic induction of 15 mT, the off time is 1 μs with a magnetic induction minus 15 mT, the operating frequency is not higher than 100 kHz. The microcircuits are used in sensors of speed of rotation of gears, in angle sensors of rotation and in sensors of the moment of sparking in automobile and industrial electronics together with a permanent magnet.

Compared to Hall sensors, magnetotransistors made on silicon wafers have a higher sensitivity and selectivity to the direction of the magnetic field; therefore, it is most promising to create sensors for determining the components of the magnetic induction vector based on magnetotransistors.

In the certificate of authorship [2], the magnetic field sensor was created on the basis of a bipolar magnetotransistor in the form of an injection-field single-chip silicon microcircuit for use in magnetically controlled position sensors. The sensor includes a bipolar magnetotransistor with two measuring collectors and with a third ring collector to limit the distribution of injected charge carriers. The base current generator is included in the base of the magnetotransistor. To increase the sensitivity of the load, the measuring collectors are made on MOS transistors connected according to the current mirror circuit. The current mirror provides amplification of the signal from the magnetotransistor without additional amplification stages. The sensor does not provide the control function by the threshold for a given value of magnetic induction, as it gives a signal with measuring parameters that are not enough to perform the control function

To increase the sensitivity in the patent [3], the magnetic field sensor is created on the basis of a bipolar magnetotransistor with one emitter, with one collector and with a base region in the form of a pocket in a silicon substrate of another type of conductivity. The reverse biased pn junction of the base and silicon substrate serves as the second collector contact. The emitter junction should be shallow, not more than 0.5 μm or with a low doping level with an impurity, so that the specific surface resistance is more than 100 Ohm / sq. The sensitivity of the sensor to a magnetic field is approximately 100% / T. For use as part of an integrated circuit, this sensor is not suitable due to the lack of isolation from other circuit elements, since it affects other elements of the microcircuit.

In the patent [4], a magnetically sensitive semiconductor device includes an emitter electrode and at least three collector electrodes mounted equidistant from the emitter electrode. The charge carriers injected by the emitter electrode migrate through the semiconductor and are extracted by the collectors. The first two base electrodes create a pulling field for charge carriers as they move from the emitter electrode in the direction of the collector electrodes. The other two base electrodes create an electric field that limits the lateral movement of charge carriers. Collector electrodes serve as output electrodes. Thanks to this design, charge carriers that are not necessary for detecting a magnetic field are eliminated, and an excellent magnetosensitivity of the device is ensured. The sensor does not provide a control function by the threshold for a given value of magnetic induction.

In [5], the design of a magnetotransistor collector and a method for its manufacture are patented. A portion of the semiconductor substrate is doped to form a base region. An emitter region and a collector region are formed in the base region by doping so that the collector region surrounds the emitter region. 16 contacts to the collector are formed symmetrically in the area of the collector. In the three-dimensional measurement of the magnetic field, 4 pairs of split contacts of the magnetotransistor collector are used. Near the emitter there are additionally doped base regions that separate the flows of injected charge carriers. A large number of contacts to the collector allows you to register three components of the magnetic field when comparing the potentials of the contacts. The sensor does not provide a control function by the threshold for a given value of magnetic induction.

In [6], a CMOS microsystem with a lateral bipolar magnetotransistor was reported. This system in combination with a permanent magnet is a key element for accurate angular non-contact measurements and is used to control angular control systems in automation and industrial applications. The integrated system includes a two-dimensional magnetic microsensor; an interface that sets the operating point of the magnetotransistor; compensation scheme for the initial unbalance; signal conditioner; analog-to-digital converter. At the system output, a digital representation of the angular position is provided. The digital unit performs linearization and calibration of the digital signal, quadrant detection and compensation through a sequential algorithm for approximating the initial unbalance, reaching 200 mT. The system has an angular resolution of 1 degree in the field of a permanent magnet of 100 mT. The sensor was not used due to the large initial unbalance in the collector voltages.

The patent [7] proposes a MOS microsystem in the form of a trigger on 4 transistors with switching of logical states using a MOS Hall sensor. MOS Hall sensors have a high noise level and do not allow operation at low magnetic fields.

The patent for the invention [8] describes an integrated tokomagnetic sensor based on a bipolar magnetotransistor with a certain ratio of the sizes of the emitter and collectors. The collectors are connected through resistances to one pole of the power source and to the contacts to the base through resistances that specify the base current. The working current is set by the resistance through the contacts to the pocket from one pole of the power source. The contacts to the substrate and the emitter are connected to the other pole of the power source. Resistance is made of polycrystalline silicon as part of the sensor. These features of the sensor reduce the initial voltage difference across the collectors of a magnetotransistor without a magnetic field. An integrated current-magnetic sensor based on a bipolar magnetotransistor has a small initial voltage imbalance of the collectors, but has an output signal in the form of a voltage difference between the collectors of a two-collector magnetotransistor, i.e. in analog form. The sensor does not provide a control function by the threshold for a given value of magnetic induction. An integrated current-magnetic sensor based on a bipolar magnetotransistor is a magnetic field transducer in an integrated gradient magnetotransistor sensor.

In the patent [9], a current source circuit with an additional current mirror with a current of opposite polarity is proposed. This circuit is built on complementary MOS transistors. The circuit includes a first current mirror on p-MOS transistors with a calibrated current source, an inverting cascade that creates a current of reverse polarity, including a second current mirror on n-MOS transistors and a source with a variable current value, which must be controlled, a memory element for recording a controlled current value, a current comparison element that maintains a constant value of the controlled current. The circuit is designed to compare two currents and maintain the magnitude of the operating current, but does not provide a pulse output signal in the presence of a certain difference in currents in the two circuits. The sensor does not contain magnetically sensitive elements. The patent [11] is a prototype.

In order to obtain an output signal in the form of pulses of on / off current of the stator current of an electric motor, it is necessary to build an integrated microsystem. The system includes two integrated current-magnetic sensors based on a bipolar n-p-n magnetotransistor; two pairs of p-MOSFETs of collector load transistors connected according to the current mirror circuit and setting the operating point of magnetotransistors; inverters for controlling the trigger and matching voltage levels of current-magnetic sensors based on a bipolar magnetotransistor and trigger input voltages, RS-trigger on CMOS transistors, output stage on CMOS transistors.

The technical task of the alleged invention is the creation of a simplified circuit-technical solution of the magnetic field gradient sensors of magnetically controlled integrated circuits based on magnetotransistors.

The technical problem of the invention is solved in that the integrated gradient magnetotransistor sensor contains two sensing elements, two amplifiers, made in the form of two current mirrors on MOS transistors, and a comparison circuit with two inputs. Sensitive elements with amplifiers are made in the form of integrated current-magnetic sensors based on bipolar magnetotransistors located at a constant distance L from each other, with the possibility of determining the gradient of the magnetic field distribution by the difference of the signals from the sensors. This simplifies the implementation of the circuitry of the magnetic field gradient sensor, which reduces the size of its crystal. Each of these sensors is connected through the current mirror, which performs the function of the load, and the output of the current mirror with the input of the corresponding CMOS inverter matching the signal level of the current-magnetic sensors and input voltages at the corresponding inputs of the comparison circuit containing the RS-trigger and the output stage, one of the outputs of the RS-trigger connected to the output CMOS cascade. Such a circuit design of an integrated gradient magnetotransistor sensor can reduce its power consumption.

The integrated gradient magnetotransistor sensor at the output has a powerful CMOS inverter and the output stage controls the voltage at the p-MOS and n-MOS transistors of the high-power CMOS inverter. This extends the functionality, as it allows you to apply a control signal through a long communication line, for example, to the input of the control device.

The integral gradient magnetotransistor sensor at the output has a powerful p-MOS transistor or an open-drain n-MOS transistor and a CMOS output stage connected to the gate of a powerful MOS transistor. This extends the functionality by generating and supplying a control signal to the actuators.

The integral gradient magnetotransistor sensor contains two sensing elements, two amplifiers, in the form of two current mirrors on MOS transistors, the sensitive elements being made as integral current-magnetic sensors based on bipolar magnetotransistors located at a constant distance from each other, with the possibility of determining the gradient of the magnetic field distribution by the difference of signals from the sensors, each of which is connected through the current mirror, which performs the function of the load, with the output of the sensor. The output of the sensor is connected to the input or gate of the p-MOS and / or n-MOS transistors with open drain. This allows us to simplify the circuitry of the sensor and actuator at high magnetic fields (five times or more than when the previously described sensor).

A common technical effect is the ability to accurately measure and determine the maximum value of the magnetic field gradient, which gives an increase in the accuracy of measuring the position of the rotor magnets of the electric machine and receiving a stator current control signal with the least time distortion of the output signal to turn on the stator current relative to the position of the rotor magnets, which increases the motor efficiency and its smooth operation.

Figure 1 shows a graph of the distribution of the induction of the magnetic field B at a distance D of about two radial magnetization rotor magnets.

Figure 2 presents the electrical circuit of an integrated gradient magnetotransistor sensor.

Figure 3 presents the electrical circuit matching inverter.

Figure 4 shows the time dependence of the output voltage of the CMOS inverter.

Figure 5 presents the electrical circuit of an integrated gradient magnetotransistor sensor with an output to MOS transistors with open drain.

Figure 6 presents the electrical circuit of an integrated gradient magnetotransistor sensor with output on CMOS transistors.

Figure 7 presents the electrical circuit of an integrated gradient magnetotransistor sensor with an output to MOS transistors with open drain when controlling a matching inverter.

The integrated gradient magnetotransistor sensor in figure 2 contains two sensing elements 1 and 2 and two amplifiers in the form of two current mirrors 3 and 4 on p-MOS transistors included in the load of the sensing elements 1 and 2. Sensitive elements 1 and 2 are made in the form of integral current-magnetic sensors based on bipolar magnetotransistors located at a constant distance L from each other, with the possibility of determining the gradient of the distribution of the magnetic field from the difference of the signals from the sensors. This simplifies the implementation of the circuitry of the magnetic field gradient sensor and reduces the size of its crystal, since it allows you to arrange sensitive elements at a minimum distance. Each of these sensors 1 and 2 is connected to the input of the corresponding CMOS inverter 5 and 6, which match the signal levels of integrated current-magnetic sensors and input voltages at the corresponding inputs of the comparison circuit containing the RS trigger 7. One of the outputs of the RS trigger 7 is connected to the output CMOS cascade 8. The output signal is generated at output 9.

The integrated gradient magnetotransistor sensor at the output of the sensor has a powerful p-MOS transistor or n-MOS transistor with an open drain and the output CMOS stage 8 is connected to the gate of the MOS transistors (Fig. 5). This, while ensuring the simplicity of the circuitry solution, expands the functionality by supplying a control signal to the actuators.

The integrated gradient magnetotransistor sensor may have a powerful CMOS inverter at the output of the sensor (Fig.6). The output stage 8 from output 9 controls the voltage at the gates of the p-MOS and n-MOS transistors of a powerful CMOS inverter. This extends the functionality by supplying a control signal through a long communication line, for example, to the input of the control device.

The integral gradient magnetotransistor sensor contains two sensing elements, two amplifiers made in the form of two current mirrors on MOS transistors, and the sensitive elements are made in the form of integrated current-magnetic sensors based on bipolar magnetotransistors located at a constant distance from each other, with the possibility of determining the magnetic distribution gradient fields according to the difference of signals from sensors, each of which is connected through current mirrors that perform the function of the load and through adjacent inverters 5 and 6 with the output of the sensor, and the output of the sensor is connected to the input or gate of the p-MOS and / or n-MOS transistors with open drain (Fig. 7). This, for any specified connection of the sensor output with the control of the indicated transistors, allows simplifying the circuitry of the sensor and actuator at high magnetic field strengths (five times greater and higher than when the previously described sensor is working).

The distribution along the axis "D" of the magnetic induction "B" at a distance D of about two radial magnets "SN" in figure 1 shows that the maximum value of the magnetic induction B of the magnetic field is opposite the middle of the magnets. Between the magnets, the induction vector is directed in the opposite direction, and near the edge of the magnet, the magnetic induction takes a zero value. For operation of the electric motor with a circular frequency "ω" it is important to fix the moment of passage of the edges of the magnets to supply current to the stator windings at the right time. At these points there is a maximum gradient of the magnetic field, while at maximum induction the gradient is zero. In addition, the polarity of induction changes near the edge of the magnet. To measure the moment of passage of the edge of the magnet, the magnetic field sensor must be gradient, i.e. to fix the difference in the magnitude of the magnetic field at a distance of "L", which is achieved by installing in the integrated gradient magnetic sensor (IGMD) at this distance two magnetotransistors, conventionally shown in the upper part of figure 1 and designated as IGMD. The sensor readout circuit should record the maximum difference between the transistors at high speed. At this point, the inclusion occurs, i.e. formation of the front of the control pulse.

The electrical circuit of the matching inverters 5 and 6 is shown in FIGS. 1 and 3. The constant voltage at the output of the current mirrors is less than the supply voltage Epit by the threshold voltage of the current mirror transistors. The operating voltage levels on CMOS circuits in two states are equal to the voltages Epit or the common point “Common”. The coordination of the voltage levels at the output of the current mirror 3, current mirror 4 and at the CMOS inputs of the RS flip-flop 7 is carried out by an inverter 13, which has a CMOS key 12 between the input 10 and the output 11. The constant voltage at the input and output of the matching inverters 5 and 6 is approximately half the tension between Epitus and Tot.

Figure 4 shows the timing diagram of a particular embodiment of the circuit. The voltage at the output of the current mirror 3 "V1", the voltage at the output of the current mirror 4 "F3" and the voltage at the output stage "V2" were obtained at a frequency of 2.5 MHz and give a delay time of on and off of about 50 ns. Supply voltage 3 V and current consumption 2.5 mA. Thus, the integrated gradient magnetotransistor sensor provides magnetic field conversion at high operating frequencies and provides the smallest temporary signal distortion to turn on the stator current relative to the position of the rotor magnets, which increases the efficiency of the electric motor and its uninterrupted operation at start-up and in the dead position with a significant reduction in energy costs compared to serial bipolar magnetically controlled integrated circuits.

Figure 5 presents the electrical circuit of an integrated gradient magnetotransistor sensor with an output to MOS transistors with open drain. When working with electric motors, the output 9 of an integrated gradient magnetotransistor sensor can be connected directly to the stator winding, which serves as a load 14 for a high-power p-MOS transistor 15 with an open drain connected to the negative pole of the “-Epit” power source or serves as a load 16 for a powerful n- MOS transistor 17 with open drain connected to the positive pole of the power supply + EPIT.

Figure 6 presents the electrical circuit of an integrated gradient magnetotransistor sensor with output on CMOS transistors. When working with electric motors controlled by a microprocessor, the output stage 8 of the CMOS is connected by the output 9 of the integrated gradient magnetotransistor sensor to the stator winding through the microprocessor. In this case, the sensor should have an output in the form of a powerful CMOS inverter, consisting of a powerful p-MOS transistor 18 and a powerful n-MOS transistor 19.

Figure 7 presents the electrical circuit of an integrated gradient magnetotransistor sensor with an output to MOS transistors with open drain controlled by a matching inverter. In strong magnetic fields, a high level of the signal from tocomagnetic sensors based on bipolar magnetotransistors allows, for example, to include matching inverters 5 and 6 directly to the gates of a powerful open-drain p-MOS transistor 20 connected to the negative pole of the power supply through the resistance 21 of the stator winding to -Epit ”or a powerful open-drain n-MOS transistor 22 connected through the resistance 23 of the stator winding to the positive pole of the“ + Epit ”power source.

The operation of the integrated gradient magnetotransistor sensor is as follows. Near the point of zero magnetic field, which has a transition from the positive direction of magnetic induction to the negative, the magnetic field gradient is fixed by the difference in the readings of two sensors, each of which is affected by a well-defined value of the magnetic field. The difference between the voltage values at the output of the sensors has a maximum value at this point. Turning on the output signals of opposite polarity on the opposite shoulders of the trigger switches the trigger and gives a pulse front at the output. With the same polarity of the magnetic field on the sensors, the gradient is less, switching does not occur and the previous state of the trigger is maintained. The transition to the other edge of the magnet changes the polarity of the current switch signals and the trigger switches in the opposite direction and generates a reverse switching signal in the form of a pulse front.

The manufacture of an integrated gradient magnetotransistor sensor is carried out according to the CMOS BIS technology, which is currently the main one for the manufacture of microelectronics products. Resistance is made of polycrystalline silicon film.

In the integrated gradient magnetotransistor sensor, the principle of measuring the voltage difference across two integrated magnetotransistor sensors with the generation of an output current control signal on the RS-trigger is adopted. This ensures high accuracy of the measurement result of the passage of the edge of the rotor magnet near the sensor and the generation of a current control signal, for example, a stator of a brushless DC motor. Due to this, the efficiency and uninterrupted operation at startup and in the dead position are increased.

An integrated gradient magnetotransistor sensor based on a bipolar magnetotransistor can reduce the distance between two magnetotransistors to 100 μm, increase the resolution and increase the sensitivity to the distribution of the magnetic field at the edge of the magnet due to its own high sensitivity of the sensor and due to the amplification of the signal on the current mirror. Compared to bipolar CMOS transistors, power losses can be reduced by reducing the voltage drop across open MOS transistors. Magnetotransistors allow, due to greater sensitivity and selectivity to the direction of magnetic induction in comparison with Hall sensors, to reduce the value of magnetic induction at which the operation occurs and the front of the output pulse is formed. The gradient mode of operation of the integral gradient magnetotransistor sensor allows you to more accurately establish the moment of passage of the magnet edge and thereby increase the motor efficiency, and is also a universal technical solution for incorporating the integral gradient magnetotransistor sensor into electric drive systems of different power levels while ensuring small dimensions and energy consumption, thanks to microelectronic performance based on a magnetotransistor and CMOS circuits.

Sources used

1. Baranochnikov M.L. / Micromagnetoelectronics // Moscow, DMK Press, 2001

2. E.I. Andreev, T.V. Persianov, Yu.N. Smirnova / Magnetic field sensor // USSR Author Certificate SU 1461324, 02/09/1987.

3. Popovic R.S., Baltes H.P. / Sensitive magnetotransistor magnetic field sensor // Patent US 4700211, October 13, 1987.

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5. Ristic L. / Collector arrangement for magnetotransistor // Patent US 5323050, June 21, 1994

6. A. Näberli, M. Schneider, P. Malcovati, R. Castagnetti, F. Maloberti, H. Baltes / 2D Magnetic Microsensor with On-Chip Signal Processing for Contactless Angle Measurement // IEEE Journal of Solid-State Circuits, 31 , pp. 1902-1907, 1996.

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Claims (4)

1. An integrated gradient magnetotransistor sensor containing two sensitive elements, two amplifiers, in the form of two current mirrors on MOS transistors, and a comparison circuit with two inputs, characterized in that the sensitive elements are made in the form of integrated current-magnetic sensors based on bipolar magnetotransistors located on a constant distance from each other, with the possibility of determining the gradient of the distribution of the magnetic field from the difference of the signals from the sensors, each of which is connected through a current mirror, in performing the load function, and the output of the current mirror with the input of the corresponding CMOS inverter matching the signal level of the current-magnetic sensors and input voltages at the corresponding input of the comparison circuit containing the RS trigger and the output stage, one of the outputs of the RS trigger is connected to the output CMOS stage. 2. The integrated gradient magnetotransistor sensor according to claim 1, characterized in that the sensor output has a powerful CMOS inverter, and the output stage is configured to control the voltage at the p-MOS and n-MOS transistors of the high-power CMOS inverter. 3. The integrated gradient magnetotransistor sensor according to claim 1, characterized in that the output of the sensor has a powerful p-MOS transistor or n-MOS transistor with an open drain, and the output CMOS cascade is connected to the gate of the MOS transistors. 4. An integrated gradient magnetotransistor sensor containing two sensing elements, two amplifiers, in the form of two current mirrors on MOS transistors, characterized in that the sensitive elements are made in the form of integrated current-magnetic sensors based on bipolar magnetotransistors located at a constant distance from each other, s the ability to determine the gradient of the distribution of the magnetic field from the difference of the signals from the sensors, each of which is connected through an amplifier that performs the function of the load, with the output sensor, the output of the sensor is connected to the input or gate of the p-MOS and / or n-MOS transistors with open drain.

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