JP2013072867A - Interface circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interface circuit which is strong against noise and has low power consumption by automatically adjusting a level of rotation signals and changing a gain of a rotation signal input circuit.SOLUTION: The interface circuit by the present invention has: an automatic adjusting function of automatically adjusting a rotation signal level of rotation signals (K sinθ F(t), K cosθ F(t)) by adjusting an input signal level of primary side signals (F(t)) using first and second rotation signals (K G sinθ F(t), K G cosθ F(t)); and a gain changing function of changing the gain of first and second rotation signal input circuits (110, 111) when inputting the rotation signals (K sinθ F(t), K cosθ F(t)) to a rotation signal processor (50).

Description

  The present invention relates to an interface circuit, and more particularly to a novel improvement for automatically adjusting a level of a rotation signal and changing a gain of the rotation signal input circuit.

  Conventionally, as a digital conversion method of an analog signal of a resolver that has been used, for example, a method disclosed in Patent Document 1 can be cited, but in a rotation signal processor in a signal processing system in which this method is used. In the interface circuit, when a rotation detector that outputs a plurality of rotation signals corresponding to the rotation angle to the secondary side by inputting a signal to the primary side, generally, the input signal level to the primary side of the rotation detector is In consideration of the S / N (signal / noise) ratio, the level of the signal component is set to a large level so that there is no problem even under a condition where the largest noise is assumed.

  For example, rotation detectors are often used for applications such as magnetic pole detection, position detection, and speed detection of motors. However, since rotation detectors apply magnetic principles, leakage from motors The influence of magnetic flux may appear as noise in each rotation signal on the secondary side of the rotation detector, and each rotation signal is set to a level that does not adversely affect the rotation detector at the maximum output of the motor.

JP 2006-17659 A

Since the conventional interface circuit is configured as described above, the following problems exist.
That is, in the signal processing method in the conventional interface circuit, the output signal level to the primary side of the rotation detector is set to be large in consideration of the influence of noise. Therefore, the input signal to the primary side of the rotation detector does not necessarily have a high level.

  However, normally, the primary side is uniquely set to a large input signal level in consideration of noise, so that the power consumed as a system of the interface circuit is large, for example, in an idling stop of an automobile. Since the load on the battery becomes large, it has been a great disadvantage for a system that attempts to save power.

In order to cope with the situation as described above, when the level of the large primary signal is not necessary, the level may be lowered. Usually, the rotation signal input circuit for inputting the rotation signal to the rotation signal processing device is used. Since the gain G is matched in accordance with the input level of the primary side signal of the rotation detector and the characteristics of the rotation detector itself, if the signal input level of the primary side signal is lowered, the rotation detector and the rotation signal processor The interface between is not established.
The present invention has been made to solve the above-described problems. In particular, the interface between the rotation detector and the rotation signal processor is maintained while lowering the input level of the primary side signal when it is not necessary. An object of the present invention is to provide an interface circuit configured as described above.

  An interface circuit according to the present invention outputs a rotation signal corresponding to a rotation angle from a secondary side of the rotation detector by inputting a primary side signal to the primary side of the rotation detector, In an interface circuit that interfaces with a rotation signal processor that processes each rotation signal, the rotation of the first and second rotation signals is adjusted by adjusting the input signal level of the primary side signal using the rotation signal. An automatic adjustment function that automatically adjusts the signal level; and a gain changing function that changes the gain of the first and second rotation signal input circuits when the rotation signal is input to the rotation signal processor. Further, the calculation signal obtained from the first and second rotation signals is compared with a reference value, and the difference is fed back to the primary side. The adjustment function is configured to compare a square sum signal of the first and second rotation signals with a reference value, and the rotation signal level automatic adjustment function is the first and second rotation signal processors. The configuration is such that a digital circuit performs from the sum of squares of the rotation signal to the level setting of the primary side signal, and the gain changing function provided in each of the rotation signal input circuits is a plurality of different preset values. And a gain setting switching means for switching each gain by switching using a gain setting signal, and the gain changing function provided in each rotation signal input circuit includes: A continuous gain setting unit that continuously changes the gain, and a gain for continuously switching the continuously changing gain according to the gain setting signal. Setting a continuous switching means is a configuration made of.

Since the interface circuit according to the present invention is configured as described above, the following effects can be obtained.
That is, by inputting a primary side signal to the primary side of the rotation detector, a rotation signal corresponding to the rotation angle is output from the secondary side of the rotation detector, and the rotation detector and each rotation signal are output. In the interface circuit that interfaces with the rotation signal processor to be processed, the rotation signal level of the first and second rotation signals is automatically adjusted by adjusting the input signal level of the primary side signal using the rotation signal. And a gain changing function for changing the gains of the first and second rotation signal input circuits when the rotation signal is input to the rotation signal processor. When the interface is established while suppressing the signal level when there is no worries about power consumption, power consumption can be suppressed and the function at the time of idling stop can be assisted.
Further, the automatic adjustment function of the rotation signal level is configured to perform from the sum of squares of the first and second rotation signals to the level setting of the primary side signal by a digital circuit in the rotation signal processor. Therefore, it is possible to fully enjoy the benefits of a semiconductor process that is becoming finer, and even if functions are added as compared with the prior art, an increase in manufacturing cost can be prevented.
In addition, the gain changing function provided in each rotation signal input circuit includes a gain setting unit including a plurality of preset different gains, and a gain setting switching for switching each gain setting by switching by a gain setting signal. Thus, the gain of each rotation signal input circuit can be freely set, and the gain can be easily changed according to the conditions of the rotation detector used on the user side.
Further, the gain changing function provided in each rotation signal input circuit includes a continuous gain setting section that is preset and continuously changes in gain, and the continuously changing gain setting is continuously set according to the gain setting signal. The gain setting continuous switching means for switching automatically can change the gain setting continuously, and finer gain setting can be performed.

1 is a schematic block diagram illustrating an interface circuit according to the present invention. It is a block diagram which shows the detail of FIG. It is a wave form diagram which shows the rotation signal of the form of FIG.

  It is an object of the present invention to provide an interface circuit that can automatically adjust the level of a rotation signal and change the gain of the rotation signal input circuit.

Hereinafter, preferred embodiments of an interface circuit according to the present invention will be described with reference to the drawings.
In FIG. 1, what is indicated by reference numeral 101 is a rotation detector to which a primary side signal F (t) is input to the primary side 101A. From the secondary side 101B of the rotation detector 101, a rotation signal is transmitted. K · sin θ · F (t) and rotation signal K · cos θ · F (t) are output and input to the first rotation signal input circuit 110 and the second rotation signal input circuit 111 of the rotation signal processor 50, respectively. .

  The first and second rotation signal input circuits 110 and 111 have a predetermined gain G, and the first and second rotation signals K, G, and the gain G from the respective rotation signal input circuits 110 and 111 are added. sin θ · F (t) and K · G · cos θ · F (t) are sent to the rotation signal processing 112 not showing a specific configuration and are supplied to the first and second squaring circuits 113 and 114. .

  The first and second square signals 115 and 116 from the first and second (absolute value) square circuits 113 and 114 are added by an adder 117 to become an absolute value square sum 118, and this absolute value square sum 118 is A peak is detected by a peak detection circuit 119 (which may not be used), and is input to the subtractor 121 as a square sum signal 120 which is a calculation signal.

  The subtracter 121 corresponds to the amplitude target value of the first rotation signal K · G · sin θ · F (t) and the second rotation signal K · G · cos θ · F (t) and is set in advance as a reference. The value 107 is input, and the subtractor 121 compares the square sum signal 120 with the reference value 107, and the difference 122 is input to a known compensator 123.

  The output signal 124 from the compensator 123 and the primary side output level initial value 125 are added by an adder 126, and an addition signal 127 is passed through a signal generator 128 and an amplifier 129 that constitute the excitation circuit 106. The primary side signal F (t) is supplied to the primary side 101A of the rotation detector 101.

In the above-described configuration, when the rotation detector 101 inputs the primary side signal F (t) to the primary side 101A, the rotation side 101B receives K · F (t) sinθ, K · F ( t) A rotation detector 101 that can obtain an amplitude-modulated signal represented by cos θ.
In the rotation signal processor 50, first and second rotation signals K · G · sin θ · F (t) multiplied by G in the first and second rotation signal input circuits 110 and 111, K · G · cos θ · F (t) is configured to be used for the rotation signal processing 112.
Here, when the square sum of each rotation signal K · G · sin θ · F (t) and K · G · cos θ · F (t) multiplied by G is obtained, a signal independent of the rotation of the rotation detector 101 is obtained as follows. Can be obtained.

  Here, even if the absolute value sum of squares is taken instead of the sum of squares, a signal independent of the rotation of the rotation detector 101 can be obtained.

The square sum signal (absolute sum of squares) 120 is a reference corresponding to the amplitude target value of the first rotation signal K · G · sin θ · F (t) and the second rotation signal K · G · cos θ · F (t). Compared with the value 107, the difference 122 is introduced into the signal generator 128 for generating the primary side signal F (t) through the compensator 123 for stabilizing the feedback loop and improving the characteristics.
Since the square sum signal 120 includes the primary signal F (t) that is a carrier component, it may be compared with the reference value 107 after passing through the peak detection circuit 119 if necessary. Is not necessary if the bandwidth is sufficiently lower than the frequency of the primary signal F (t).
In addition, the primary side output level initial value 125 is added to the output signal 124 which is the output of the compensator 123. This starts the circuit from a state close to the target value to some extent in order to quickly settle the feedback loop. Therefore, it is used.
By adopting the above configuration, the feedback loop always operates to make the difference between the square sum signal 120 as the control deviation and the reference value 107 zero. As a result, the first rotation signal K · G · sin θ · F (t), the second rotation signal K · G · cos θ · F (t) is automatically adjusted to a level corresponding to the set reference value 107.

In the present invention, as described above, the primary side signal F is obtained using the first rotation signal K · G · sin θ · F (t) and the second rotation signal K · G · cos θ · F (t). By adjusting the input signal level of (t), the rotation signal levels of the first rotation signal K · G · sin θ · F (t) and the second rotation signal K · G · cos θ · F (t) are automatically adjusted. It has an automatic adjustment function.
Further, the gains of the first and second rotation signal input circuits 110 and 111 when the rotation signals K · sin θ · F (t) and K · cos θ · F (t) are input to the rotation signal processor 50 are changed. It has a gain changing function for (changing).

The gain changing function of the provided in each rotation signal input circuit 110 and 111, the gain setting unit 300 having a plurality of gain G different preset switches the respective gain G by switching by the gain setting signal G ₁ Gain setting switching means 302.

Therefore, when changing the gain G of each rotation signal K · G · sin θ · F (t) and K · G · cos θ · F (t) of each of the rotation signal input circuits 110 and 111, first, Among a plurality of different gains G set in advance in the gain setting unit 200, a gain G having an optimum magnitude is selected according to the level of noise from the other party wearing the rotation detector 101 at that time. 302 setting the gain G is finished by switching the switching by the gain setting signal G ₁ is inputted to the rotation signal input circuit 110 and 111 with the.

The above-described gain changing function has been described with respect to a configuration in which a plurality of preset gains G are individually switched and set. However, as another form, the preset gains G are not individual but continuous. a continuous gain setting unit 200A, such as a variable resistor configured to value changes Te, the gain G that changes the continuously switches continuously in response to the gain setting signal G ₁ by the continuous gain setting unit 301 Gain setting continuous switching means 302A (for example, a configuration for electronically switching the variable resistor).

Therefore, the automatic adjustment of the respective rotation signal gain G of the input circuit 110 and 111 to alter the X times from the original state by the gain setting signal G ₁ rotation signal level, the primary side signal F (t) is 1 / X times. Accordingly, the gain G of the rotation signal input circuits 110 and 111 is decreased and the primary signal F (t) is increased only when the noise is large, and the gain G of the rotation signal input circuits 110 and 111 is decreased when there is no concern about noise. When the secondary signal is increased and there is no concern about noise, the rotation signal input circuit gain G is increased and the primary signal F (t) is set small so that the primary signal F (t) is constantly set. It is not necessary to increase the size, and power consumption in the interface circuit can be suppressed.

As for the gain switching method, if the rotation signal input circuits 110 and 111 are amplifiers composed of resistors and OP amplifiers, the input resistance value or the feedback resistance value can be switched by a multistage switch or the like. setting signals G ₁ may be used as the switch control signal. Or if gain than the possible changes continuously, it is possible to more granular control by inputting the analog signal as a gain setting signal G _1.
Incidentally, the gain setting signal G ₁ may be used a signal in any form the user side, detect and gain setting to the rotation detector 101 is rotated by monitoring the output state of the rotation signal processor 50 can be switched signals G _1, or by detecting the motor current is connected to the rotation detector 101 motor (not shown) switches the gain setting signal G1, the signal generated in response to appropriate usage of equal It can be performed.

The configuration of FIG. 2 is mainly composed of a digital circuit obtained by converting the main part of the configuration of FIG. 1 into a digital circuit. The first rotation signal K · G · sin θ · F (t), the second rotation signal K · G · An example is shown in which the circuit from the sum of squares of cos θ · F (t) (first and second square circuits 113 and 114) to the level setting (adder 126) of the primary side signal F (t) is configured by a digital circuit. Yes.
In addition, the same code | symbol is attached | subjected and demonstrated to the same or equivalent part as the structure of FIG.

  The rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) multiplied by G in each of the rotation signal input circuits 110 and 111 are converted to A through the A / D converters 200 and 201, respectively. / D-converted into a two's complement code, digitally summed with the square of the absolute value by each of the square circuits 113 and 114, and compared with the digital reference value 107 corresponding to the target value of each rotation signal by the digital subtractor 121 The A difference 122 which is a control deviation obtained by digital subtraction is introduced into the signal generator 128 via an integrator which is a compensator 123. In this embodiment, since it is assumed that the feedback loop bandwidth is set sufficiently lower than the frequency F (t) by the compensator 123, the peak detection circuit shown in FIG. 1 is omitted. .

  In the first (absolute value) square circuit 113 and the second (absolute value) square circuit 114, the digital outputs 200a and 201a from the A / D conversion circuits 200 and 201 are converted into multipliers 200b and 201b and MSB mask processing 200c. , 201c, and is added by the adder 117 and supplied to the subtractor 121 as the square sum signal 120.

  FIG. 3 shows a result of simulating changes in the first and second rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) in the embodiment of FIG. The initial values of the first and second rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) are set to 1Vp− at the primary side output level initial value (digital) in FIG. The target value is set to 2 Vp-p with the digital reference value. Finally, the first and second rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) are stable at the target signal level.

  Further, the first and second rotation signals K · G · sin θ · F (t), K · G · cos θ · F (t) can be changed by the variable setting of the gain G by the gain setting switching means 302 in the embodiment shown in FIG. Since the gain G is variably adjusted and the characteristic improving operation with respect to the external noise is the same as the configuration and operation of FIG. 1, the description thereof is omitted here.

The configuration of the interface circuit according to the present invention is summarized as follows.
By inputting the primary side signal F (t) to the primary side 101A of the rotation detector 101, the rotation signal K · sin θ · F (t) corresponding to the rotation angle from the secondary side 101B of the rotation detector 101 is obtained. , K · cos θ · F (t), and the rotation detector 101 and the rotation signal processor 50 for processing the rotation signals K · sin θ · F (t) and K · cos θ · F (t). In the interface circuit that performs the interface, by adjusting the input signal level of the primary side signal F (t) using the rotation signals K · sin θ · F (t) and K · cos θ · F (t), 1. Automatic adjustment function for automatically adjusting the rotation signal level of the second rotation signal K · G · sin θ · F (t), K · G · cos θ · F (t), and the rotation signal K · sin θ · F (t ), K · cos θ · F (t) are input to the rotation signal processor 50 in the first and second rotation signals. Gain changing function for changing the gain G of the signal input circuits 110 and 111, and the first rotation signal K · G · sin θ · F (t) and the second rotation Comparing the calculation signal 120 obtained from the signal K · G · cos θ · F (t) with the reference value 107 and feeding back the difference 122 to the primary side 101A, and automatically adjusting the rotation signal level The function is a configuration for comparing the square sum signal 120 of the first and second rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) with a reference value 107, and The automatic adjustment function of the rotation signal level is obtained by calculating a sum of squares of the first and second rotation signals K · G · sin θ · F (t) and K · G · cos θ · F (t) in the rotation signal processor 50. (First and second squaring circuits 113 and 114) from the primary side signal F (t ) Level setting (adder 126) is configured by a digital circuit, and the gain changing function provided in each of the rotation signal input circuits 110 and 111 is configured to set a plurality of gains G that are set in advance and are different from each other. a gain setting unit 300 with the gain setting switching means 302 for switching the switching by the gain setting signal G ₁ each gain G, a configuration consisting of, also, provided to the each rotation signal input circuit 110, 111 It said gain changing function includes a continuous gain setting unit 301 which changes the preset continuously gain G, the gain setting for switching continuously in accordance with the gain G that changes the continuously gain setting signal G ₁ And a continuous switching means 302A.

  An object of the present invention is to obtain an interface circuit that automatically adjusts the level of a rotation signal, changes the gain of the rotation signal input circuit, changes the level of the rotation signal with respect to noise, and can suppress power consumption. .

50 Rotation signal processor 101 Rotation detector 101A Primary side 101B Secondary side 106 Excitation circuit 107 Reference value 110 First rotation signal input circuit 111 Second rotation signal input circuit K · sinθ · F (t), K · cosθ · F (t) Rotation signal K · G · sinθ · F (t), K · G · cosθ · F (t) First and second rotation signals 112 Rotation signal processing 113 First (absolute value) square circuit 114 Second (Absolute value) square circuit 115 First (absolute value) square signal 116 Second (absolute value) square signal 117 Adder 118 (Absolute value) Square sum 119 Peak detection circuit 120 (Absolute value) Square sum signal 121 Subtractor 122 difference 123 compensator 124 output signal 125 primary output level initial value 126 adder 127 adds the output 128 signal generator 129 amplifier F (t) primary signal 300 gain setting unit G gain _{G 1} gain setting signal 301 continuously Gay Setting unit 302 gain setting switching means 302A gain setting successive switching means

Claims (6)

By inputting the primary side signal (F (t)) to the primary side (101A) of the rotation detector (101), it corresponds to the rotation angle from the secondary side (101B) of the rotation detector (101). The rotation signal (K · sinθ · F (t), K · cosθ · F (t)) is output, and the rotation detector (101) and each rotation signal (K · sinθ · F (t), K · cosθ) In the interface circuit that interfaces with the rotation signal processor (50) that processes F (t))
By adjusting the input signal level of the primary side signal (F (t)) using the rotation signals (K · sin θ · F (t), K · cos θ · F (t)), first and second An automatic adjustment function that automatically adjusts the rotation signal level of two rotation signals (K, G, sin θ, F (t), K, G, cos θ, F (t)) and the rotation signal (K, sin θ, F (t) ), K · cos θ · F (t)) having a gain changing function for changing the gain of the first and second rotation signal input circuits (110, 111) when the rotation signal processor (50) is input. Interface circuit characterized by   The operation signal (120) obtained from the first and second rotation signals (K · G · sinθ · F (t), K · G · cosθ · F (t)) is compared with the reference value (107), The interface circuit according to claim 1, wherein the difference (122) is fed back to the primary side (101A).   The automatic adjustment function of the rotation signal level is based on the square sum signal (120) of the first and second rotation signals (K · G · sinθ · F (t), K · G · cosθ · F (t)). 2. The interface circuit according to claim 1, wherein the interface circuit is configured to be compared with a value.   The automatic adjustment function of the rotation signal level includes the first and second rotation signals (K · G · sinθ · F (t), K · G · cosθ · F (t)) in the rotation signal processor (50). 4. The interface circuit according to claim 1, wherein a digital circuit performs from the sum of squares calculation to the level setting of the primary side signal (F (t)). 5. The gain changing function provided in each of the rotation signal input circuits (110, 111) includes a gain setting unit (300) having a plurality of gains (G) set in advance and the gains (G) as gain setting signals. (G ₁₎ interface circuit according to any one of claims 1 to 4, wherein the gain setting switching means for switching the switching (302), in that it consists by. The gain changing function provided in each of the rotation signal input circuits (110, 111) includes a continuous gain setting unit (301) in which the gain (G) changes in advance and the gain (G) that changes continuously. The interface circuit according to any one of claims 1 to 4, further comprising: gain setting continuous switching means (302A) for continuously switching according to a gain setting signal (G ₁ ).

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