DE102006000037A1 - Rotation angle detector, e.g. for detecting crankshaft angle, produces output signal whose level varies when rotation angle corresponds to predetermined candidate angle - Google Patents

Abstract

Rotation angle detector includes a field generator and a magnetic detector comprising a number for magnetic sensors. A pulse signal generator receives the analog sensor signals and produces an output signal whose level changes when the rotation angle of a rotary object corresponds to a predetermined candidate angle. The rotation angle signal is produced from the analog sensor signals by calculation of trigonometric functions.

Description

The The present invention relates to a rotation angle detecting device. which is equipped with magnetic sensors.

Rotation angle detection devices The so-called magnetic pickup type (MPU) are known. Such an MPU rotation angle detection device comprises a magnetic recording sensor and a rotor that rotates with the Object rotates, for detecting a rotation angle of the rotating Object corresponding to an output of the pickup sensors, which also rotate with the rotation of the rotor. The rotor is on Gear type motor with in uniform Intervals on the outer circumference the same teeth arranged, with the exception of a predetermined toothless area. The MPU rotation angle detection device detects a reference rotation angle by means of a special waveform or waveform of the output signal of the recording sensor, the preset smooth part of the Zahnradtyprotors corresponds. thereupon becomes a rotation angle of the rotating object relative to the reference rotation angle by comparing the level of the output signal with the level of determined specific waveform to finally the rotation angle (rotation angle) to determine the rotating object.

on the other hand is a rotation angle detecting means for detecting a rotation angle of a rotating object within a range from 0 ° and 360 ° known and in published patent application JP-A-62-95402. This rotation angle detection device includes a pair of Hall elements and permanent magnets. In this facility the Hall elements are provided in such a way that they are relative rotate to the permanent magnets when the rotating (rotating to be detected) object rotates. The angle of rotation of the rotating object is from the analog output signals of the Hall elements means obtained from the calculation of trigonometric functions.

In The previous MPU rotation angle detection device needs the rotor be prepared in such a way that it is a suitable Gap between the rotor and the pickup sensor for detecting the reference angle and the relative rotation angle thereof. That the size (dimension) of the rotor varies, and it can the output signals of the recording sensor also vary.

at the latter rotation angle detection device can output the signal by disturbances or Noise from outside disturbed so that a detection error can be caused.

Of the The present invention is therefore based on the object, a compact To provide rotation angle detecting device, the rotation angle of a rotating (rotating) object with much lower detection errors detected.

According to the present The invention in conjunction with claim 1 comprises a rotation angle detection circuit a field shaping device for forming or generating a magnetic field, a in the magnetic field arranged magnetic detection device, the magnetic sensor elements has a rotation angle signal shaping device for generating analog sensor signals and pulse signal shaping means for shaping an output pulse signal whose level changes as the angle of rotation of the rotating object one of predetermined candidate angles corresponds, from the analog sensor signals of the magnetic detection device.

There the pulse signal forming means forms a pulse signal for indication the angle of rotation of a rotating object when the angle of rotation of the rotating Object corresponds to one of preset candidate angles, can the rotation angle without interference by a noise from the outside be recorded.

According to the present Invention in conjunction with claim 2, the magnetic sensor elements have at least one pair of basic sensor elements and can so be arranged that the phase of the analog sensor signal each the magnetic sensor elements becomes different to the reverse one Phase of the analog sensor signals of the other magnetic sensor elements. In this way, the rotation angle signal from the analog sensor signals the basic magnetic sensor elements by means of the calculation of trigonometric functions formed, and there are the default candidate angle through Compare the analog sensor signals of the magnetic sensor elements shaped with a threshold level. Therefore, the candidate angle pulse signals formed from the output signals of the Hall elements without an A / D conversion or be formed.

According to the present The invention in conjunction with claim 3 is an offset matching circuit provided such that the pulse signal shaping device, the output pulse signal from the analog sensor signals can form their offsets the offset matching circuit is eliminated.

According to the present The invention in conjunction with claim 4 is an AC coupling circuit provided for eliminating offsets of the analog sensor signals the magnetic sensor elements.

According to the present Invention in conjunction with claim 5 are a first offset adjustment device and a second offset adjusting device. The first Offset matching eliminates offsets that are in the analog Sensor signals of the selected Group of magnetic sensor elements are included when the rotation angle of the rotating object is determined. The second offset angle adjustment device includes a coupling circuit for removing in the analog Sensor signals all the magnetic sensor elements contained offsets when the angle of rotation of the rotating object is determined. The pulse signal shaping device comprises a first pulse signal shaping device, a second pulse signal shaping device and a selector. The rotation angle signal shaping device forms a rotation angle signal by means of the calculation of trigonometric functions from the analogue Sensor signals of the basic magnetic sensor elements after removal the offsets. The first pulse signal shaping device forms a first one Candidate pulse signal by comparing the angle of rotation with a the first preset candidate angle, and the second pulse signal shaping device forms a second candidate pulse signal by comparing the angle of rotation with a pre-set reference value. The selector selects that first candidate pulse signal, if the rotational speed or the rotational or rotational speed of the rotating object is less than a preset speed and the second candidate pulse signal if the rotational speed of the rotating object not smaller than the preset speed is.

According to the rotation angle detecting device in conjunction with claim 6, the magnetic detection device, the rotation angle signal shaping device and the pulse signal shaping device arranged in a common chip.

Further Objects, features and characteristics of the present invention as well as the functions of the corresponding parts of the present invention are obtained from the study of the following detailed description, the associated claims and the figures clearly. Show it:

1 FIG. 4 is a block diagram of a rotation angle detecting apparatus according to the first embodiment of the invention; FIG.

2 FIG. 12 is a block diagram of an ignition system for an internal combustion engine including the rotation angle detection device according to the first embodiment; FIG.

3A a schematic representation of a main part of the rotation angle detecting device according to the first embodiment, and 3B a side sectional view of the in 3A according to the line 3B-3B cut part,

4 4 is a graph illustrating output signals of a Hall element pair with respect to the rotational angles of a rotor;

5 4 is a graph illustrating a characteristic of operating angles with respect to the rotational angle of the rotor;

6 FIG. 4 is a graph illustrating a characteristic of output rotation angles with respect to the rotation angles of the rotor; FIG.

7 FIG. 4 is a table showing a relationship between the positive or negative signs of the output signals of the Hall elements and the rotation angles. FIG.

8th FIG. 4 is a graph showing a relationship between the rotational angle of the rotor and the pulse signals. FIG.

9A a schematic representation of a plan view of the rotation angle detecting device according to a second embodiment, and 9B a side sectional view of in 9A shown device corresponding to a section along the line IXB-IXB,

10 FIG. 4 is a block diagram illustrating a rotation angle detecting device according to the second embodiment of the present invention; FIG.

11A a graph illustrating characteristics of the output signals of six Hall elements with respect to the rotation angle, and 11B 4 is a graph showing output pulse signals of a pulse signal generating circuit for indicating candidate angles.

12 FIG. 4 is a block diagram illustrating a rotation angle detecting apparatus according to a third embodiment of the present invention; FIG.

13 a schematic representation for illustrating a rotation angle detecting device according to a fourth embodiment the present invention

14 FIG. 4 is a schematic diagram illustrating a change of the rotation angle detecting device according to the fourth embodiment; FIG.

15 a schematic representation of a rotation angle detecting device according to a fifth embodiment of the present invention, and

16 a schematic representation of a rotation angle detecting device according to a sixth embodiment of the invention.

A Variety of embodiments according to the invention will be described below with reference to the accompanying figures.

(First embodiment)

A rotation angle detecting device 10 According to the first embodiment of the invention will be with reference to the 1 - 8th described.

The rotation angle detection device 10 is commonly used as a crank angle detecting device (crankshaft angle detecting device) attached to an ignition device 12 for an internal combustion engine together with an electronic control unit (ECU) 40 is arranged as it is in 2 is shown. The rotation angle detection device 10 provides both analog and pulse signals with respect to the rotational angles of a crankshaft of the engine (hereinafter referred to as crank angle). The electronic control unit (ECU) 40 determines (distinguishes) a cylinder to be ignited on the basis of the analog signals and the pulse signals.

As shown in the 1 . 3A and 3B includes the rotation angle detecting device 10 a cylindrical yoke 20 , a pair of arcuate permanent magnets 22 and 24 , a pair of reverb elements 30 and 31 and a semiconductor chip (hereinafter referred to as a sensor chip) 70 in which a drive circuit 50 , an amplifier 52 , an A / D converter 54 , an offset matching circuit 56 , a control circuit 58 , a rotational angle waveform shaping circuit (RA waveform shaping circuit) 60 a pulse signal shaping circuit 62 and the like together with the Hall elements 30 and 31 are formed.

The yoke 20 and the permanent magnets 22 and 24 rotate together with a rotating object (not shown) and form a field-shaping device. The permanent magnets 22 and 24 are corresponding to a 180 ° interval on the inner wall of the cylindrical yoke 20 for providing a parallel and uniform magnetic field opposite each other.

The sensor chip 70 is attached to a support device that does not rotate with the rotating object, so that the Hall elements 30 and 31 in a central part of the yoke 20 are arranged.

The hall elements 30 and 31 be for operation by means of the drive circuit 50 controlled by a constant current or a constant voltage. The hall elements 30 and 31 are each arranged in the form that they form an angle of 90 ° to each other in the direction of rotation of the rotating object.

The yoke turns 20 with the permanent magnets 22 and 24 as shown in 4 , then create the Hall elements 30 and 31 each sinusoidal output signals 100 and 101 , which have a phase difference of 90 ° to each other. This means that the output signal 100 of the Hall element 30 and the output signal 101 of the Hall element 31 have a sine-cosine relation to each other.

Thus, the following expressions can be formed if: the rotation angle of the rotating object is θ, the voltage of the output signal 100 of the Hall element 30 Va is the voltage of the output signal 101 of the Hall element 30 Vb is a coefficient that focuses on the amplification of the Hall elements 30 and 31 k, is the magnetic flux density produced by means of the permanent magnets 22 and 24 is B, and the magnitude of the constant and the Hall elements supplied current I is. Va = kBI · sinθ (1) Vb = kBI × sin (θ + 90) = kBI × cos θ (2)

The amplifier 52 amplifies the output signals 100 and 101 the Hall elements 30 and 31 , The A / D converter 54 converts the analogue amplified output signals into numerical digital data by sampling these signals according to a predetermined cycle.

Are offsets or DC components in the output signals Va and Vb of the Hall elements 30 and 31 then the offset matching circuit eliminates these offsets. The control circuit 58 forms a rotation angle signal (RA signal) and a pulse signal in cooperation with the rotation angle signal shaping circuit 60 and the pulse signal shaping circuit 62 ,

The control circuit 58 reads the output signals of the Hall elements 30 and 31 while they are not subjected to a magnetic field. Then, the rotation angle detecting device stores 10 the levels of the read output signals as offset values. In detail, the rotation angle detecting device includes 10 a nonvolatile memory in the offset matching circuit 56 , and the control circuit 58 stores the offset values in the non-volatile memory. The control circuit 58 subtracts the stored offset values from the output signals of the Hall elements 30 and 31 which were read while a rotation angle signal and a pulse signal were being formed. Thus eliminate the control circuit 58 and the offset matching circuit 56 the offsets at the Hall elements 30 and 31 , Therefore, the values Va and Vb are numerical digital values converted by the A / D converter after the offsets and the gain thereof have been corrected.

The control circuit 58 calculates a value tan θ from the values Va / Vb and an operating angle 110 by means of the arctangent of the same, from which results: Va / Vb = sin θ / cos θ = tan θ (3) θ = arctane (Va / Vb) (4)

Consequently the operating angle has a cycle of 180 °.

The control circuit 58 determines the rotation angle of the rotating object within an angle of 360 ° by detecting the positive or negative sign of the values Va and Vb, as shown in FIG 7 is shown. After that, the control circuit forms 58 an initial angle 120 by adding a corresponding offset value to the operating angle 110 based on the determined angle of rotation. The control circuit 58 controls the rotation angle signal shaping circuit 60 for generating an analog rotation angle signal with respect to the output angle 120 , The control circuit 58 thus sends the rotation angle signal shaping circuit 60 a digital signal of the output angle 120 , The rotation angle signal forming circuit 60 converts the digital signal into the output angle by means of a D / A converter (not shown) 120 in the form of an analog angle signal whose level is proportional to the output angle.

The control circuit 58 controls the pulse signal shaping circuit 62 for generating a pulse signal whose signal level is subject to change if the rotation angle of the rotating object is one of the plurality of preset candidate angles. In particular, the candidate angles include an angle to be detected by means of the rotation angle detection device 10 , Will the rotation angle detecting device 10 as a crank angle detecting device of an ignition device for an internal combustion engine 12 are used, then the candidate angles are the crank angles (crankshaft angles) corresponding to the ignition times (ignition timing). In particular, the control circuit compares 58 a plurality of thresholds, each corresponding to the candidate angles, having an analog value of the output angle 120 , and changes the level of the output pulse signal of the pulse signal shaping circuit 62 from a high level to a low level or from a low level to a high level if the output angle 120 equal to one of the candidate angles.

As shown in 2 are the sensor chip 70 and the electronic control unit ECU 40 by means of an angle signal transmission line 80 and a pulse signal transmission line 81 connected. The A / D converter 42 converts analog rotation angle signals into numeric digital signals.

The central processing unit CPU 44 comprises a memory ROM and a memory RAM for storing programs for determining the rotation angle (rotation angle) of the rotating object from the digital numerical data and the pulse signal. As shown in 8th determines the CPU CPU 44 a reference angle from the output angle 120 , If the signal level of the pulse signal changes from one to the other according to the reference angle, the CPU selects CPU 44 a candidate angle from the plurality of candidate angles. Immediately after the CPU CPU 44 has determined the reference angle to 45 °, the CPU selects CPU 44 For example, "60 °" out of twelve candidate angles when the pulse signal drops, and if the pulse signal rises thereafter, the CPU selects CPU 44 The selected candidate angle is the rotation angle of the rotating object when the signal level of the pulse signal changes.

rotates Furthermore, if the rotating object in two ways, then the Direction of rotation determined by means of an incremental rotary encoder with which a pair of different in phase to each other Pulse signals are formed.

Since the rotation angle detection device according to the first embodiment detects the rotation angle of the rotating object from the pulse signal, detection errors can be significantly reduced. Further, the yoke 20 and the permanent magnets 22 and 24 along with the rotating object relative to the sensor chip 70 for changing the direction of the means of the Hall elements 30 and 31 To turn magnetic field to be detected has one Variation of the position of the yoke 20 and the permanent magnets 24 no adverse effect on the change of direction in the magnetic field. Furthermore, the detection error can be minimized because the Hall elements 30 and 31 with a high accuracy on the sensor chip 70 are formed.

Second Embodiment

A rotation angle detecting device 210 According to the second embodiment of the invention will be described below with reference to the 9 to 11 described. In particular, the same reference numerals as in the first embodiment denote the same or substantially the same parts or components as in the first embodiment.

The rotation angle detection device 210 includes six Hall elements 30 to 35 , The hall elements 30 - 35 be by means of the drive circuit 50 each supplied with a constant current. Each of the six hall elements 30 to 35 is located at a position relative to the center 20a a circle 90 is not symmetrical to a position at which another Hall element is arranged, as in 9 is shown. In other words, the Hall elements are circumferentially on half a side of the circle 90 and arranged with an extent in radial directions, so that the phase of the output signal of each of the Hall elements 30 to 35 is different from the reverse phases of the output signals of the other Hall elements 30 to 35 , In particular, the Hall elements 30 to 35 arranged circumferentially within a zone of 150 ° at intervals of 30 °, so as to provide in this way pulse signals with twelve candidate angles, which are offset from each other by 30 ° and, as shown in FIG 11B , ranging over a range of 0 ° to 360 °.

The rotation angle signal forming circuit 60 forms the rotation angle signal of the analog sensor signals of the Hall elements 30 and 31 by calculating trigonometric functions in the same way as described above. To specify the Hall elements 30 and 31 is hereinafter referred to as a basic Hall elements.

As shown in 10 includes the rotation angle detecting device 210 the second offset matching circuit 256 in the sensor chip 70 in addition to the first offset matching circuit 56 in the rotation angle detecting device 10 according to the first embodiment of the invention. The pulse signal shaping circuit 62 of the first embodiment is constituted by a pulse signal shaping circuit 262 replaced.

The second offset adjustment circuit 256 eliminates the offsets of the output signals of the Hall elements 30 to 35 , The second offset adjustment circuit 256 includes variable resistors, each with the Hall elements 30 to 35 are connected, wherein the resistance value for removing the offsets can be changed. The Pulsesignalformungsschal device 262 forms or generates pulse signals whose level as a function of the comparison result of the output signals of the Hall elements 30 to 35 are variable after offset removal with a threshold. In other words, the pulse signal shaping circuit 262 forms or generates the candidate angle pulse signals from the output signals of the Hall elements 30 to 35 without an A / D conversion.

The pulse signal shaping circuit 262 changes the level of the output pulse signal when the comparison result of one of the output signals 100 - 105 the Hall elements 30 to 35 with a threshold from the positive sign (+) to the minus sign (-) or vice versa. In other words, the pulse signal shaping circuit 262 Adjusts a signal level of the output pulse signal to the high level when the signal level of the output signal 104 from the positive side to the negative side as shown in 11A changes at a rotation angle of 30 °. The pulse signal shaping circuit 262 Further sets the signal level of the output signal to the low level when the signal level of the output signal 105 from the positive side to the negative side as shown in 11A at the rotation angle of 60 ° changes. The pulse shaping circuit 262 thus forms a pulse signal which rises at the rotation angle of 30 ° and drops at the rotation angle of 60 °.

The pulse signal shaping circuit 262 can thus form twelve pulse signals corresponding to the twelve candidate angles and different within a range of 360 ° to each other by 30 °, wherein the signal level of the output signals of the Hall elements 30 to 35 is compared with the zero threshold level (0). Thus, the candidate angles can be desirably adjusted by determining the position of each of the second Hall elements as well as the threshold.

In the rotation angle detecting device 210 Thus, according to the second embodiment of the invention, pulse signals can be obtained from the output signals of the Hall elements 30 to 35 be formed without A / D conversion. This structure avoids sampling errors due to the A / D conversion.

(Third Embodiment)

A rotation angle detecting device 310 according to the third embodiment is after standing with reference to 12 described. The rotation angle detection device 310 includes an offset adjustment circuit 356 containing the offset matching circuit 56 of the first embodiment, an AC coupling circuit 357 and a set of a pair of first and second candidate pulse signal shaping circuits 362 and 363 and a selection circuit 364 containing the pulse shaping circuit 62 of the first embodiment replaced. The offset adjustment circuit 356 , the AC coupling circuit 357 , the first and second candidate pulse signal shaping circuits 362 and 363 and the selection circuit 364 are together in the sensor chip 70 arranged.

The offset adjustment circuit 356 eliminates the offset of the fundamental Hall elements 30 and 31 on the basis of the offset value thereof, when the magnetic field is not around the fundamental Hall elements 30 and 31 is formed in the same manner as in the first embodiment. Thus, the offset matching circuit 356 the offsets of the basic Hall elements 30 and 31 regardless of the frequencies of the output signals 100 and 101 the Hall elements 30 and 31 remove.

The first candidate pulse signal shaping circuit 362 has substantially the same structure as the pulse signal shaping circuit 62 of the first embodiment. The first candidate pulse signal shaping circuit 362 forms on the basis of numerical data obtained by means of the offset matching circuit 356 has been corrected, first candidate signals corresponding to the pulse signals generated by the pulse signal shaping circuit 62 were formed.

The AC coupling circuit 357 eliminates the offsets of the Hall elements. The second candidate pulse signal shaping circuit 363 has substantially the same structure as the pulse signal shaping circuit 262 of the second embodiment. The second candidate pulse signal shaping circuit 363 forms or generates the second candidate pulse signals from the output signals of the Hall elements 30 to 35 , their offsets by means of the AC coupling circuit 357 which were corrected by the pulse signal shaping circuit 262 of the second embodiment, wherein the AC coupling circuit 357 a circuit is made up of smaller capacitors than the offset matching circuit 256 consists. In particular, the AC coupling circuit 357 do not eliminate the offsets of the output signals if the rotational speed of the rotating object is extremely small. Therefore, the selection circuit selects 364 either the first or the second candidate pulse signal according to the rotational speed of the rotating object as its output signal. In other words, the output circuit 364 selects the first candidate pulse signals if the rotational speed of the rotating object is lower than a preset speed, or otherwise selects the second candidate pulse signals. In this way, a detection error due to a sampling error is eliminated.

(Fourth Embodiment)

A rotation angle detecting device 410 according to the fourth embodiment of the invention will be described below with reference to the 13 and 14 described.

As shown in the 13 and 14 includes the rotation angle detecting device 410 eighteen (18) Hall elements 430 to 447 arranged in a circle to provide thirty-six (36) candidate angles whose phase angles are each different by 10 ° from each other. The hall elements 439 to 447 as shown in 13 can be arranged on diagonally opposite sides of the circle, so that each Hall element is arranged at a position which is not symmetrical with respect to the center of the circle to a position at which another Hall element is arranged, as shown in FIG 14 is shown by simply reversing the phase of the output signals thereof.

Since the in 13 shown arrangement further distances (for example 20 °) between the Hall elements (with the exception of the distance between the Hall elements 430 and 447 ), it is easier to arrange feed lines for connecting the Hall elements between the Hall elements than in the arrangement as shown in FIG 14 with intervals of 10 ° between them. In other words, the arrangement as shown in FIG 13 the chip size of the sensor chip can be smaller than in the arrangement of 14 enable. Preferably, the Hall elements 430 and 443 provided as the basic Hall elements, the basic Hall elements 30 and 31 correspond to the previous embodiments, since these are arranged on Posi functions at an angular distance of 90 ° to each other.

(Fifth Embodiment)

A rotation angle detecting device 510 according to the fifth embodiment will be described below with reference to 15 described.

Eighteen Hall elements 430 to 447 are divided into two groups, each corresponding to two concentric circles 90 and 91 are arranged: the Hall elements 430 to 438 are on the inner circle 90 arranged at intervals of 20 °; and the hall elements 439 to 447 are on the circle 91 arranged at intervals of 20 °. The hall elements 430 to 438 are with respect to the Hall elements 439 to 447 offset by 10 ° in the direction of rotation.

These Arrangement provides any further distances between the Hall elements ready so that the connecting lines for connecting the hall elements be formed in a simple manner between the Hall elements can, and thus providing a compact sensor chip can be.

(Sixth Embodiment)

A rotation angle detecting device 610 according to the sixth embodiment will be described below with reference to 16 described.

Eighteen Hall elements 430 to 447 are divided into two groups, each on the circle 90 are arranged in different layers (planes) of the sensor chip.

The hall elements 430 to 438 are arranged on a layer with intervals of 20 °, and the Hall elements 439 to 447 are arranged on another layer with the same intervals. The hall elements 430 to 438 are from the hall elements 439 to 447 offset by 10 ° in the direction of rotation. This arrangement also provides further gaps between the Hall elements, so that connection lines for connecting the Hall elements between the Hall elements can be formed in a simpler manner, so that a compact sensor chip can be provided.

(Modifications)

• (1) die vorstehend beschriebenen Hallelemente können durch Magnetwiderstandselemente ersetzt werden;
• (2) die Grund-Hallelemente 30 und 31 des ersten oder dritten Ausführungsbeispiels können durch drei oder mehr Hallelemente ersetzt werden;
• (3) die Hallelemente 30 bis 35 des zweiten oder dritten Ausführungsbeispiels oder die Hallelemente 430 bis 447 des vierten bis sechsten Ausführungsbeispiels können durch zwei oder mehr Hallelemente ersetzt werden;
• (4) die Grund-Hallelemente 30 und 31, der Verstärker 52, der A/D-Wandler 54, die Offsetanpassungsschaltung 56, die Drehwinkelsignalformungsschaltung 60 und die Pulssignalformungsschaltung 62 können in verschiedene Gruppen zur Anordnung mittels unterschiedlicher Chips aufgeteilt werden; und
• (5) die Offsetanpassungsschaltung 256 kann durch eine AC-Kopplungsschaltung ersetzt werden.

The rotation angle detecting device according to the invention may also have the following modifications:

• (1) the above-described Hall elements can be replaced by magnetic resistance elements;
• (2) the fundamental Hall elements 30 and 31 of the first or third embodiment may be replaced by three or more Hall elements;
• (3) the Hall elements 30 to 35 of the second or third embodiment or the Hall elements 430 to 447 of the fourth to sixth embodiments may be replaced by two or more Hall elements;
• (4) the basic Hall elements 30 and 31 , the amplifier 52 , the A / D converter 54 , the offset adjustment circuit 56 , the rotation angle signal forming circuit 60 and the pulse signal shaping circuit 62 can be divided into different groups for arrangement by means of different chips; and
• (5) the offset matching circuit 256 can be replaced by an AC coupling circuit.

In the foregoing description of the present invention has been the Invention in conjunction with specific embodiments thereof disclosed. However, it is obvious that different modifications and changes the specific embodiments of the present invention possible are without departing from the scope of the invention according to the appended claims.

Thus, a rotation angle detection circuit includes 10 . 210 . 310 . 410 . 510 and 610 for detecting a rotation angle of a rotating object permanent magnet parts 20 . 22 and 24 for generating a magnetic field, Hall elements 30 to 35 and 430 to 447 which are arranged in the magnetic field, an analog rotation angle signal shaping circuit 60 and a pulse signal shaping circuit 62 . 262 . 362 and 363 which forms from the analog sensor signals of the Hall elements, an output pulse signal whose level changes when the rotation angle of the rotating object corresponds to one of preset candidate angles.

Claims (11)

Rotation angle detection device ( 10 . 210 . 310 . 410 . 510 . 610 ) for detecting a rotational angle of a rotating object, comprising: a field-shaping device ( 20 . 22 . 24 ), which is connected to the rotating object for rotation, for generating a magnetic field, in which by the field shaping device ( 20 . 22 . 23 Magnetic detecting means arranged, wherein the magnetic detection means comprises a plurality of magnetic sensor elements ( 30 to 35 . 430 to 447 ) for generating analog sensor signals having different phase to each other when the rotating object is rotating, a rotation angle signal forming device ( 60 ) for generating an analogue output signal corresponding to the rotation angle of the rotating object from the analogue sensor signals of the magnetic detection device, characterized by a pulse signal shaping device ( 62 . 262 . 362 . 363 ) for generating an output signal from the analog sensor signals of the magnetic detectors whose level changes when the rotation angle of the rotating object corresponds to one of preset candidate rotation angles. Rotation angle detection device ( 210 . 310 . 410 . 510 . 610 ) according to claim 1, characterized in that the magnetic sensor elements ( 30 to 35 . 430 to 447 ) comprise at least one pair of basic sensor elements arranged in such a way that the phase of the analog sensor signal of each of the magnetic sensor elements ( 30 to 35 . 430 to 447 ) becomes different from the reverse phases of the analog sensor signals of the other magnetic sensor elements ( 30 to 35 . 430 to 447 ), the rotation angle signal shaping device ( 60 ) the rotation angle signal from the analog sensor signals of the basic magnetic sensor elements ( 30 . 31 ) by the calculation of trigonometric functions, and the preset candidate angles by comparing the analog sensor signals of the magnetic sensor elements ( 30 to 35 . 430 to 447 ) are formed with a threshold level. Rotation angle detection device ( 10 . 210 . 310 . 410 . 510 . 610 ) according to claim 1 or 2, further characterized by an offset matching circuit ( 56 . 256 ), so that the pulse signal shaping device ( 62 . 262 . 362 . 363 ) can form the output pulse signal from the analog sensor signals whose offsets are canceled by the offset matching circuit. Rotation angle detection device ( 310 ) according to claim 3, further characterized by an AC coupling circuit ( 357 ) for eliminating the offsets of the analog sensor signals of the magnetic sensor elements ( 30 - 35 ). Rotation angle detection device ( 310 ) according to claim 1, characterized by: a first offset matching device ( 356 including a memory for storing data of offsets of a selected group of the magnetic sensor elements contained in the analog sensor signals ( 30 . 31 ), when the base magnetic sensor elements are not subjected to the magnetic field, wherein the first offset adjusting means eliminates the offsets contained in the analog sensor signals of the selected group of magnetic sensor elements in the detection of the rotational angle of the rotating object, a second offset angle adjusting means (Fig. 357 ) including a coupling circuit, wherein the second offset angle adjusting means in the analog sensor signals of all of the magnetic sensor elements ( 30 to 35 ) eliminates offsets contained in the detection of the rotational angle of the rotating object, wherein: the pulse signal shaping device comprises a first pulse signal-shaping device ( 362 ), a second pulse signal shaping device ( 363 ) and a selector ( 364 ), the rotation angle signal shaping device ( 60 ) the rotation angle signal by calculating trigonometric functions from the analog sensor signals of the basic magnetic sensor elements ( 30 . 31 ) after removal of the offsets, the first pulse signal shaping device ( 362 ) generates a first candidate pulse signal by comparing the angle of rotation with one of the preset candidate angles, the second pulse shaping device ( 363 ) generates a second candidate pulse signal by comparing the angle of rotation with a preset reference value, and the selector ( 364 ) selects the first candidate pulse signal if the rotational speed of the rotating object is smaller than a preset speed, and selects the second candidate pulse signal if the rotational speed of the rotating object is not smaller than the preset speed. Rotation angle detection device ( 10 . 210 . 310 . 410 . 510 . 610 ) according to claim 1, 2 or 5, characterized in that the magnetic detection means, the rotation angle signal forming means ( 60 ) and the pulse signal shaping device ( 62 . 262 . 362 . 363 . 364 ) are arranged on a chip. Rotation angle detection device ( 10 . 210 . 310 . 410 . 510 . 610 ) according to one of claims 1 to 6, characterized in that the magnetic sensor elements ( 30 to 35 . 430 to 447 ) Hall elements are. A rotation angle detecting device according to claim 7, characterized in that the Hall elements concentric Circles are arranged so that each Hall element at a position is arranged, the respect the center of the concentric circle is not symmetrical to one Position is where another Hall element is arranged. Rotation angle detection device ( 10 ) according to claim 1, characterized in that the pulse signal shaping device ( 62 ) comprises means for generating the output pulse signal when the analog rotation angle signal becomes equal to one of a plurality of threshold values corresponding to the preset candidate angles. Angle detection device according to claim 2, characterized in that the basic sensor elements ( 30 . 31 ) are arranged at positions that are offset from each other in phase by 90 °. Rotation angle detection device ( 10 . 210 . 310 . 410 . 510 . 610 ) according to claim 1, characterized in that the pulse signal shaping device ( 62 . 262 . 362 . 363 ) comprises means for generating the output signal when the analog rotation angle signal becomes equal to one of a plurality of threshold values corresponding to the preset candidate angles.