JP3342879B2 - Sensor signal processing circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is a sensor signal processing circuit FIELD OF THE INVENTION, and a more particularly ECU and the sensor unit, in the the sensor unit
Waveform shaping for processing a sensor and a signal detected by the sensor
And the ECU is connected to a signal line.
And a sensor signal processing circuit configured to be connected via the . The ECU is an Electronic Control U
It is an abbreviation of nit and is generally called an electronic control unit.

[0002]

2. Description of the Related Art Generally, ABS (anti-lock brake syst)
em) is to control the hydraulic pressure of the brake so that the wheels do not lock completely when a sudden brake is applied, but continue to rotate. A sensor for detecting the speed is provided. A sensor signal processing circuit is formed to process signals detected by these sensors.

A conventional sensor signal processing circuit will be described with reference to the drawings. FIG. 7 is a block diagram schematically showing the sensor signal processing circuit 60.
Is a sensor unit 6 for detecting a wheel speed signal used for ABS.
1 and the ECU 62. Sensor section 61
Includes a first terminal 73, a second terminal 74, and a third terminal 75 for connection to the sensor 64, the waveform shaping circuit 63, and the ECU 62, and the filter 65 and the waveform Shaping means 66, signal output means 72
And a power supply connection line 71. The filter 65 connected to the sensor 64 is connected to the waveform shaping unit 66,
The waveform shaping means 66 is connected to the second terminal 74 via the signal output means 72. Further, the waveform shaping means 66 is also connected to the third terminal 75 via a connection line 81.
Connection line 81 between waveform shaping means 66 and third terminal 75
Is connected to a signal output means 72. The power supply connection line 71 connects the waveform shaping means 66 to the first terminal 73.

The first terminal 73, the second terminal 74 and the third terminal
Are connected to a first terminal 78, a second terminal 79, and a third terminal 80 of the ECU 62, respectively.
The first terminal 78 of the CU 62 is connected to the power source 76,
Is connected to the input side of the comparator 77, and the other input side of the comparator 77 is connected to one end of a power supply V3 for applying a reference voltage. The power supply 76
A resistor R6 is interposed between the input terminal and the comparator, and the third terminal 80 and the other end of the power supply V3 are grounded.

FIG. 8 shows a circuit diagram of the sensor signal processing circuit 60 more specifically. One end of a coil L that generates an electromotive force by the rotation of a gear 29 attached to the wheel is connected to the + input side of a comparator 30 via a resistor R1, and the other end of the coil L is connected to two thresholds. A power supply V1, connected in parallel to provide a voltage,
It is connected to the negative input side of the comparator 30 via V2 and the switch 31. A capacitor C1 and a resistor R2 are connected in parallel between the other end of the coil L and the input side of the comparator 30.

[0006] The output side of the comparator 30 is branched.
One is connected back to the switch 31 and the other is a resistor R
3 and connected to the base of the transistor Q1.
You. The switch 31 determines whether the output of the comparator 30 is high or low.
According to the reference voltage V₁ , V_Two Switch. Accordingly
Comparator 30, switch 31, and reference voltage V₁ ,
V _Two Constitutes a hysteresis comparator. Ma
The collector of the transistor Q1 connected to the second terminal 74
The emitter of the transistor Q1 is connected via a connection line 81.
Connected to the third terminal 75. Transistor Q1
Connection line 81 branches between the third terminal 75 and the emitter of
This connection line 81 extends to the power supply V1, V2
Have been. The resistor R3 and the base of the transistor Q1
And a connection line 82 branches from the connection line 82.
Is connected to the connection line 81 via the resistor R4.

The first terminal 73 is connected to the comparator 30 via the power supply connection line 71, and further connected from the comparator 30 to a connection line 81 between the third terminal 75 and the coil L.

The first terminal 73, the second terminal 74 and the third terminal
Are connected to a first terminal 78, a second terminal 79, and a third terminal 80 of the ECU 62, respectively.
The first terminal 78 of the CU 62 is connected to the power source 76,
Is connected to the input side of the comparator 77, and the other input side of the comparator 77 is connected to one end of a power supply V3 for obtaining a reference voltage. A resistor R6 is interposed between the power supply 76 and the input side of the comparator 77, and the third terminal 80 and the other end of the power supply V3 are grounded.

[0009]

In the above-described sensor signal processing circuit 60, the signal detected by the sensor 64 is processed by the waveform shaping circuit 63 built in the sensor section 61, so that a signal resistant to noise is processed by the ECU 62. Can be entered. However, since the driving power of the waveform shaping circuit 63 incorporated in the sensor unit 61 is supplied from the power supply 76 of the ECU 62, the waveform shaping circuit 6
3 and a signal line from the waveform shaping circuit 63 to the ECU 62 are separately wired. Therefore, the sensor unit 61
There is a problem that the number of harnesses for connecting the ECU and the ECU 62 increases, which increases costs and complicates wiring.

When the number of sensors 64 is large, the number of harnesses becomes large. Therefore, the waveform shaping circuit 63 which requires power supply is not built in
Although the waveform shaping circuit 63 is built in the 62 side, in this case, a signal having a weak output from the electromagnetic pickup is directly transmitted to the E side.
A shield wire was used to output to the CU 62 side. However, shielded wires are expensive and
There is a problem that the waveform shaping circuit 63 built in the ECU 62 also needs measures against noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a low-cost sensor signal processing circuit which requires a small number of wirings, is resistant to noise, and has low noise.

[0012]

In order to achieve the above object, a sensor signal processing circuit according to the present invention comprises an ECU and a sensor.
A sensor and a sensor detected by the sensor in the sensor unit.
And a waveform shaping circuit for processing the obtained signal.
So that the circuit and the ECU are connected via signal lines
In the configured sensor signal processing circuit, the waveform shaping is performed.
The circuit includes a waveform shaping unit, a frequency detection unit, a signal output unit, and a power supply unit connected to the waveform shaping unit and controlled by an output signal from the signal output unit, and an output from the waveform shaping unit. When the signal is at a low level, power is supplied from the ECU to the waveform shaping circuit via the signal line.

[0013] Alternatively, and a ECU and the sensor unit, the
Processes sensors and signals detected by the sensors in the sensor unit
A waveform shaping circuit, and the waveform shaping circuit and the EC
In the sensor signal processing circuit that is configured to the U are connected via a signal line, the said waveform shaping circuit, waveform shaping means, signal output means, Russia - connected to the level limit means and said waveform shaping means is the b - power supply means via the level restriction means is controlled by the output signal from the signal output means is arranged, the output from the waveform shaping means b - when the level through the signal line The ECU
Supplies a first power supply voltage to the waveform shaping circuit, and when an output from the waveform shaping means is at a high level, a second power supply voltage lower than the first power supply voltage is supplied to the ECU via the signal line. , And is supplied to the waveform shaping circuit.

[0014]

According to the above construction, the ECU and the sensor unit are included.
The sensor and the signal detected by the sensor
And a waveform shaping circuit for processing the waveform.
In the sensor signal processing circuit configured to the serial ECU is connected via a signal line, the waveform shaping circuit
A power supply means connected to the waveform shaping means, a frequency detection means, a signal output means and the waveform shaping means and controlled by an output signal from the signal output means, wherein an output from the waveform shaping means is Since the power is supplied from the ECU to the waveform shaping circuit via the signal line when the level is at the level, the output from the waveform shaping means incorporated in the sensor unit becomes low. In this case, power is supplied from the ECU to the waveform shaping circuit via a signal line. In other words, the power of the ECU supplied to the waveform shaping circuit built in the sensor unit is supplied by a harness connected to output a signal from the sensor. The manufacturing cost of the sensor signal processing circuit is reduced.

[0015] Alternatively, and a ECU and the sensor unit, the
Processes sensors and signals detected by the sensors in the sensor unit
A waveform shaping circuit, and the waveform shaping circuit and the EC
In the sensor signal processing circuit that is configured to the U are connected via a signal line, the said waveform shaping circuit, waveform shaping means, signal output means, Russia - connected to the level limit means and said waveform shaping means is the b - power supply means via the level restriction means is controlled by the output signal from the signal output means is arranged, the output from the waveform shaping means b - when the level through the signal line The ECU
Supplies a first power supply voltage to the waveform shaping circuit, and when an output from the waveform shaping means is at a high level, a second power supply voltage lower than the first power supply voltage is supplied to the ECU via the signal line. Is supplied from the ECU to the waveform shaping circuit by a signal line when the output from the waveform shaping means incorporated in the sensor unit becomes low. When power is supplied to the power supply and the output from the waveform shaping unit goes high, power is supplied from the ECU to the waveform shaping circuit by the signal line while maintaining a constant voltage level. In other words, the power of the ECU supplied to the waveform shaping circuit built in the sensor unit is supplied by a harness connected to output a signal from the sensor. , The production cost of the sensor signal processing circuit is reduced, and a sensor signal processing circuit resistant to noise is realized.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sensor signal processing circuit according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a sensor signal processing circuit 10. The sensor signal processing circuit 10 includes a sensor unit 11 for detecting a wheel speed signal used for ABS and an ECU 12. The sensor unit 11 includes a sensor 14 for detecting an electromotive force generated by rotation of a wheel, a waveform shaping circuit 13 and an E.
The waveform shaping circuit 13 includes a filter 15, a waveform shaping unit 16, and a frequency detecting unit 1. The first terminal 23 and the second terminal 24 are connected to the CU 12.
7, a switch 18, a signal output means 22, and a power supply means 21 are provided. The filter 15 connected to the sensor 14 is connected to the waveform shaping unit 16 and the waveform shaping unit 1
6 is connected to the first terminal 23 via the switch 18 and the signal output means 22. Further, the waveform shaping means 16 is also connected to the second terminal 24 by a connection line 35,
Connection line 35 between waveform shaping means 16 and second terminal 24
Is connected to signal output means 22. A frequency detecting means 1 is provided between the waveform shaping means 16 and the switch 18.
7 is connected to the input side, and the output side of the frequency detecting means 17 is connected to the switch 18. The power supply means 21 constituted by the constant voltage circuit 19 and the rectifier circuit 20 is connected to a connection line 35 between the waveform shaping means 16 and the second terminal 24, and further comprises a signal output means 22 and a first terminal 23 is connected to a connection line 36.

The first terminal 23 and the second terminal 24 are connected to the first terminal 27 and the second terminal 28 of the ECU 12, respectively, and the first terminal 27 of the ECU 12 is connected to a resistor R.
6, the power supply 25 is connected to the power supply 25, and the input terminal of the comparator 26 is connected to the first terminal 27. One end of a power supply V3 for applying a reference voltage is connected to the other input side of the comparator 26,
Terminal 28 and the other end of the power supply V3 are grounded.

FIG. 2 shows a circuit diagram of the sensor signal processing circuit 10 more specifically. One end of a coil L that generates an electromotive force by the rotation of a gear 29 attached to the wheel is connected to the + input side of a comparator 30 via a resistor R1, and the other end of the coil L is connected to two thresholds. A power supply V1, connected in parallel to provide a voltage,
It is connected to the negative input side of the comparator 30 via V2 and the switch 31. A capacitor C1 and a resistor R2 are connected between the coil L and the input side of the comparator 30.
And are connected in parallel.

The output side of the comparator 30 is branched, one is connected back to the switch 31, and the other is connected to the resistor R
3 is connected to the base of the transistor Q1. The collector of the transistor Q1 is connected to the first terminal 23.
And the emitter of the transistor Q1 is connected to the connection line 35.
Is connected to the second terminal 24 via the. A connection line 35 is connected between the emitter of the transistor Q1 and the second terminal 24.
Are branched, and the connection line 35 extends to the power supplies V1 and V2. A connection line 36 branches from between the resistor R3 and the base of the transistor Q1, and the connection line 36 is connected to the connection line 35 via the resistor R4.

The first terminal 23 and the transistor Q1
Is connected to the comparator 30 via the diode D1 and the resistor R5.
To the connection line 35 between the terminal 24 and the coil L. One end of a capacitor C2 is connected to a connection line 37 between the diode D1 and the resistor R5, the other end of the capacitor C2 is grounded, and a connection line 37 between the resistor R5 and the comparator 30 is connected to a connection line 37. Zener diode D
2 is connected, and the other end of the Zener diode D2 is grounded.

The first terminal 23 and the second terminal 24 are connected to the first terminal 27 and the second terminal 28 of the ECU 12, respectively. The first terminal 27 of the ECU 12 is connected to a power supply via a resistor R6. The input side of the comparator 26 is connected to the first terminal 27. One end of a power supply V3 for applying a reference voltage is connected to the other input side of the comparator 26, and the second terminal 28 and the other end of the power supply V3 are grounded.

3A to 3G are time charts of signals output from each device of the sensor signal processing circuit 10, in which FIG. 3A is a power supply voltage level of the ECU 12, and FIG. sensor signal passing through, (c) an output signal whose waveform is shaped by the waveform shaping means 16, (d) is detected frequency detection output signal by the frequency detection means 17, (e) is from the waveform shaping circuit 13 Output signal, (f)
Is the level of the power supply voltage output from the rectifier circuit 20,
(G) indicates the level of the power supply voltage supplied to the waveform shaping means 16.

In the sensor signal processing circuit 10 configured as described above, when the power supply voltage of the ECU 12 is turned on as shown in FIG. 3A, the wheel speed information is added to the wheels. It is detected by the electromotive force generated in the coil L as the gear 29 rotates. The electromotive force generated in the coil L outputs a signal having a frequency proportional to the wheel speed. The output signal passes through a filter 15 formed by a resistor R2 and a capacitor C1, and a certain frequency is taken out. The signal enters a comparator 30 for waveform shaping and frequency detection. For example, comparator 3
When V1 and V2 are set as 0 reference voltages, as shown in FIGS. 3B and 3C, the filter 1
When the signal voltage output from 5 becomes higher than V1, the output signal from the comparator 30 becomes high, and when the signal voltage becomes lower than V2, the output signal from the comparator 30 becomes low. In this case, FIG. 3 as shown (d), the order is detected that is greater than the frequency with the frequency of the signal from the sensor 14 to frequency and the output voltage of the sensor signal is directly proportional, the sensor signal V ₁ When the level becomes higher than the level, it can be substituted by judging that the frequency is higher than a certain frequency.

When the output signal from the comparator 30 becomes high, the transistor Q1 is turned on and grounded, and the voltage on the collector side becomes substantially zero. Accordingly, as shown in FIG. 3E, the voltage level at the first terminal 23 becomes substantially zero when the waveform shaping output from the comparator 30 becomes high, and the output of the waveform shaping signal from the comparator 30 becomes low. When it becomes low, the power supply voltage becomes 12 V, which is substantially equal to the power supply voltage of the ECU 12. As shown in FIG. 3 (f), the output signal from the comparator 30 is B - if that is the power supply voltage supplied is rectified by retracted diode D1 to the connection line 37 from the ECU 12,
At the connection of the capacitor C2, a voltage level substantially equal to that of the ECU 12 is secured, while the comparator 30
Is high , the signal is output from the capacitor secured by the capacitor C2. Then, as shown in FIG. 3G, the voltage is adjusted to a constant voltage level by the resistor R5 and the Zener diode D2 and supplied to the comparator 30.

As described above, in the sensor signal processing circuit 10 according to the above embodiment, the output from the comparator 30 built in the sensor section 11 becomes low when the frequency of the sensor signal is lower than a certain value, Only in the above case, switching between high and low is performed. Then, when the signal from the comparator 30 becomes low, power can be supplied from the ECU 12 to the waveform shaping circuit 13 using the signal line. Therefore, the sensor unit 1
When the power supply of the ECU 12 is supplied to the waveform shaping circuit 13 built in 1, the signal from the sensor 14 can be supplied by a harness connected to output the signal to the ECU 12, so that the number of harnesses is reduced. And a sensor 14 in the sensor unit 11.
Since the waveform of the signal is shaped, there is no need to use a shield wire for these harnesses, and an output signal from the sensor 14 which is low in cost and resistant to noise can be obtained.

Next, another embodiment of the sensor signal processing circuit according to the present invention will be described. FIG. 4 is a block diagram schematically showing the sensor signal processing circuit 40. The sensor signal processing circuit 40 includes a sensor unit 41 for detecting a wheel speed signal used for the ABS and the ECU 12. The sensor unit 41 includes a sensor 44 for detecting rotation of a wheel, a waveform shaping circuit 43, and a first terminal 4 for connection to the ECU 12.
The waveform shaping circuit 43 includes a filter 45, a waveform shaping unit 46, a signal output unit 52, a low level limiting unit 53, and a power supply unit 51. . The filter 45 connected to the sensor 44 is connected to a waveform shaping unit 46, and the waveform shaping unit 46 is connected to a first terminal 47 via a signal output unit 52 and a low level limiting unit 53. Further, the waveform shaping means 46 is also connected to a second terminal 48 by a connection line 54, and a signal output means 52 is connected to a connection line 54 between the waveform shaping means 46 and the second terminal 48. .
The waveform shaping unit 46 is connected to a power supply unit 51 including a rectifier circuit 50 and a constant voltage circuit 49, and the power supply unit 51 is connected to the first terminal 47.

The first terminal 47 and the second terminal 48 are connected to the first terminal 27 and the second terminal 28 of the ECU 12, respectively, and the first terminal 27 of the ECU 12 is connected to a resistor R.
The power supply 25 is connected to the input terminal of the comparator 26 via the first terminal 27. A power supply V3 for applying a reference voltage is connected to the other input side of the comparator 26, and the second terminal 28 and the other end of the power supply V3 are grounded.

FIG. 5 shows a circuit diagram of the sensor signal processing circuit 40 more specifically. One end of a coil L that generates an electromotive force by the rotation of a gear 29 attached to the wheel is connected to the + input side of a comparator 30 via a resistor R1, and the other end of the coil L is connected to a center reference voltage V.
Fourth, it is connected to the input side of-of the comparator 30 via the power supplies V1 and V2 and the switch 31 connected in parallel to give two kinds of threshold voltages. A capacitor C1 and a resistor R2 are connected in parallel between the coil L and the input side of the comparator 30.

The output side of the comparator 30 is branched, one of which is connected back to the switch 31, and the other of which is a resistor R.
3 is connected to the base of the transistor Q1. The collector of the transistor Q1 is connected to a first terminal 47 via a resistor R8, and the emitter of the transistor Q1 is connected to a second terminal 48 via a connection line. A connection line 54 branches between the emitter of the transistor Q1 and the second terminal 48, and the connection line 54 extends to the power supplies V1 and V2. A connection line 55 branches from between the resistor R3 and the base of the transistor Q1, and this connection line 54 is connected to the connection line 54 via the resistor R4.
It is connected to the.

A connection line 56 branches between the first terminal 47 and the resistor R8, and the connection line 56 is connected to the resistor R7.
And a resistor R5, and is connected to the comparator 30, and further extends from the comparator 30 to a connection line 54 between the second terminal 48 and the coil L. One end of a capacitor C2 is connected to a connection line 56 between the resistors R7 and R5, and the other end of the capacitor C2 is grounded.
Further, a connection line 56 between the resistor R5 and the comparator 30
Is connected to one end of a Zener diode D2, and the other end of the Zener diode D2 is grounded.

The first terminal 47 and the second terminal 48 are connected to the first terminal 27 and the second terminal 28 of the ECU 12, respectively. The first terminal 27 of the ECU 12 is connected to a power supply via a resistor R6. The input side of the comparator 26 is connected to the first terminal 27. One end of a power supply V3 for applying a reference voltage is connected to the other input side of the comparator 26, and the second terminal 28 and the other end of the power supply V3 are grounded.

In the above embodiment, the case where the resistor R8 is used as the low-level limiting means 53 has been described. However, the present invention is not limited to the resistor R8 alone, and a Zener diode, for example, may be used.

FIGS. 6A to 6G are time charts of signals output from each device of the sensor signal processing circuit 40. FIG. 6A shows the level of the power supply voltage supplied from the ECU 12, and FIG. A sensor signal passed through the filter 45,
(C) is an output signal whose waveform has been shaped by the waveform shaping means 46, (d) is an output signal from the waveform shaping circuit 43,
(E) shows the level of the power supply voltage output from the rectifier circuit 50, (f) shows the level of the power supply voltage supplied to the waveform shaping means 46, and (g) shows the low / high judgment by the ECU 12.

In the sensor signal processing circuit 40 configured as described above, when the power supply voltage of the ECU 12 is turned on as shown in FIG. 6A, the wheel speed information is attached to the wheels. It is detected by the electromotive force generated in the coil L as the gear 29 rotates. The electromotive force generated in the coil L outputs a signal having a frequency proportional to the wheel speed. The output signal passes through a filter 45 formed by a resistor R2 and a capacitor C1, and a certain frequency is extracted. Enters the comparator 30 to perform waveform shaping and frequency detection. For example, a constant voltage is secured by V4 as a signal voltage from the filter 45,
When V1 and V2 are set as the threshold voltages of the comparator 30, as shown in FIGS. 6B and 6C, when the signal voltage from the sensor 44 becomes larger than V1, the output from the comparator 30 is increased. When the signal becomes high and the signal voltage from the sensor 44 becomes smaller than V2, the output signal from the comparator 30 becomes low.

When the output signal from the comparator 30 becomes high, the transistor Q1 is turned on and grounded, and the voltage on the collector side drops. However, the voltage level is lower than a certain value by the resistor R8 as the low level limiting means 53. Will be secured. Accordingly, as shown in FIG. 6D, the output signal from the first terminal 47 has a high waveform shaping output from the comparator 30, and a constant level is secured even when the emitter of the transistor Q1 is grounded. When the output of the waveform shaping signal from the comparator 30 is low, the signal becomes high. The voltage at the connection of the capacitor C2 is shown in FIG.
As shown in (e), the output signal from the comparator 30 is B - and is in the case that the power supply voltage supplied from the ECU12 is drawn to the connection line 56, a constant voltage level is ensured by the resistor R7 On the other hand, comparator 3
Even when the output signal from 0 is high , the ECU
While the power supply voltage supplied from 12 is maintained at a certain value by the resistor R8, it does not drop below a certain voltage level due to the discharge from the resistor R5 and the capacitor C2. Thereafter, as shown in FIG. 6F, the voltage is adjusted to a constant voltage by the resistor R5 and the Zener diode D2 and supplied to the comparator 30. Then, the ECU 12 makes a low / high determination as shown in FIG. 6G based on the output signal from the sensor 44, and detects the wheel speed.

As described above, in the sensor signal processing circuit 40 according to the above-described embodiment, the output from the comparator 30 incorporated in the sensor section 41 is low when the level of the sensor signal is equal to or lower than a certain level, and is higher than a certain level. High only when Then, when the signal voltage from the waveform shaping circuit 43 becomes low, power can be supplied from the ECU 12 to the waveform shaping circuit 43 using the signal line. In addition, even when the signal from the comparator 30 becomes high, it is possible to supply power from the ECU 12 to the waveform shaping circuit 43 at a certain level or more secured by the low level limiting means 53. Therefore, the power supply of the ECU 12 supplied to the waveform shaping circuit 43 built in the sensor unit 41 is changed to the signal from the sensor 44 as E.
Since it can be supplied by a harness connected to output to the CU 12 side, the number of harnesses can be reduced, and since the signal of the sensor 44 is waveform-shaped in the sensor section 41, these harnesses can be supplied. It is not necessary to use a shielded wire, and an output signal from the sensor 44 that is strong at low cost and resistant to noise can be obtained.

[0037]

The sensor signal processing circuit according to the present invention as described in detail above, according to the present invention includes an ECU and the sensor unit, the sensor
A sensor and a wave for processing a signal detected by the sensor
The waveform shaping circuit and the ECU.
In the sensor signal processing circuit configured to be connected through a signal line, the waveform shaping circuit includes a waveform shaping unit, a frequency detection unit, a signal output unit, and a signal output unit connected to the waveform shaping unit. A power supply means controlled by an output signal of the control circuit, so that when the output from the waveform shaping means is at a low level, power is supplied from the ECU to the waveform shaping circuit via the signal line. With this configuration, when the output from the waveform shaping unit incorporated in the sensor unit becomes low, power can be supplied from the ECU to the waveform shaping circuit by a signal line. That is, the power of the ECU supplied to the waveform shaping circuit built in the sensor unit can be supplied by the harness connected to the ECU side to output a signal from the sensor. Since the number of wires can be reduced, and a signal is sent to the ECU after the waveform is shaped in the sensor section, the harness does not need to be a shield wire, and the manufacturing cost of the sensor signal processing circuit can be reduced. In addition to this, an output signal from a sensor that is resistant to noise can be obtained.

[0038] Alternatively, and a ECU and the sensor unit, the
Processes sensors and signals detected by the sensors in the sensor unit
A waveform shaping circuit, and the waveform shaping circuit and the EC
In the sensor signal processing circuit that is configured to the U are connected via a signal line, the said waveform shaping circuit, waveform shaping means, signal output means, Russia - connected to the level limit means and said waveform shaping means is the b - power supply means via the level restriction means is controlled by the output signal from the signal output means is arranged, the output from the waveform shaping means b - when the level through the signal line The ECU
Supplies a first power supply voltage to the waveform shaping circuit, and when an output from the waveform shaping means is at a high level, a second power supply voltage lower than the first power supply voltage is supplied to the ECU via the signal line. From the ECU to the waveform shaping circuit by a signal line when the output from the waveform shaping means incorporated in the sensor section goes low. Power can be supplied, and power is supplied from the ECU to the waveform shaping circuit side by a signal line while securing a voltage level equal to or higher than a predetermined value even when the output from the waveform shaping unit becomes high. Can be. That is, the power of the ECU supplied to the waveform shaping circuit built in the sensor unit can be supplied by a harness connected to output a signal from the sensor, so that the number of harnesses is reduced. In addition, since the signal is sent to the ECU after the waveform is shaped in the sensor section, the harness does not need to be a shielded wire, so that the manufacturing cost of the sensor signal processing circuit can be reduced and noise can be reduced. A strong sensor signal processing circuit can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an embodiment of a sensor signal processing circuit according to the present invention.

FIG. 2 is a circuit diagram more specifically showing the sensor signal processing circuit of FIG. 1;

FIGS. 3A to 3G are time charts of signals output from each device of the sensor signal processing circuit.

FIG. 4 is a block diagram schematically showing another embodiment of the sensor signal processing circuit.

FIG. 5 is a circuit diagram more specifically showing the sensor signal processing circuit of FIG. 4;

FIGS. 6A to 6G are time charts of signals output from each device of the sensor signal processing circuit.

FIG. 7 is a block diagram schematically showing a conventional sensor signal processing circuit.

FIG. 8 is a circuit diagram more specifically showing the sensor signal processing circuit of FIG. 7;

[Explanation of symbols]

 10, 40 sensor signal processing circuit 11, 41 sensor unit 12 ECU 13, 43 waveform shaping circuit 14, 44 sensor 16, 46 waveform shaping means 17 frequency detecting means 18, 51 power supply means 53 low level limiting means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/00 G01D 5/245 102 G01D 5/248 G01P 3/481

Claims (2)

(57) [Claims] An electronic control unit includes an ECU and a sensor unit.
Within the sensor and the waveform processing the signal detected by the sensor
The waveform shaping circuit and the ECU.
In the sensor signal processing circuit configured to be connected through a signal line, the waveform shaping circuit includes a waveform shaping unit, a frequency detection unit, a signal output unit, and a signal output unit connected to the waveform shaping unit. Power supply means controlled by an output signal is provided, and when the output from the waveform shaping means is at a low level, power is supplied from the ECU to the waveform shaping circuit via the signal line. A sensor signal processing circuit characterized in that: 2. An ECU, comprising : an ECU; a sensor unit;
Within the sensor and the waveform processing the signal detected by the sensor
The waveform shaping circuit and the ECU.
In a sensor signal processing circuit configured to be connected via a signal line, the waveform shaping circuit includes a waveform shaping unit, a signal output unit,
B - level limit means and connected to said waveform shaping means the B - power supply means via the level restriction means is controlled by the output signal from the signal output means is arranged,
When the output from the waveform shaping means is at a low level, a first power supply voltage is supplied from the ECU to the waveform shaping circuit via the signal line. When the output from the waveform shaping means is at a high level, the first power supply voltage is supplied to the waveform shaping circuit. A sensor signal processing circuit, wherein a second power supply voltage lower than the first power supply voltage is supplied from the ECU to the waveform shaping circuit via the signal line.