JP6853664B2 - Amplification device with anomaly diagnosis function - Google Patents

Description

The present invention relates to an amplification device having an abnormality diagnosis function for diagnosing an abnormality when an abnormality occurs in the built-in amplifier.

In fields such as car electronics, in order to improve the safety of vehicles while driving, it is necessary to detect abnormalities in electronic circuits including electronic components and substrates at an early stage, and in particular, drive large currents such as power amplifiers. It is desirable that the amplification device provided with the amplifier capable of performing the abnormality diagnosis function. This abnormality diagnosis function generates an abnormality diagnosis signal when its own abnormal current, abnormal heat generation, output short circuit, etc. occur during the operation of the amplifier, and is controlled by a microcomputer (hereinafter referred to as "microcomputer") or the like. It is a function to send to the device. The control device that receives the abnormality diagnosis signal can determine the content of the abnormality diagnosis signal, stop the amplifier in which the abnormality has occurred, display an error, record an error log, and the like.

FIG. 7 shows an example of the amplification device 20C having a conventional general abnormality diagnosis function in which on / off control is performed by the microcomputer 10, and FIG. 8 shows the timing chart.

In the microcomputer 10, T11 is an on / off control output terminal, and the drain of the open drain type NMOS transistor M11 is connected to the microcomputer 10. T12 is an abnormality diagnosis input terminal for inputting an abnormality diagnosis signal.

In the amplification device 20C, the amplifier 21 is connected between the signal input terminal T21 and the signal output terminal T22. T24 is an on / off control input terminal connected to the on / off control output terminal of the microcomputer 10, and is pulled up by the resistor R1. T25 is an abnormality diagnosis output terminal connected to the abnormality diagnosis input terminal T12 of the microcomputer 10, and is pulled up by the resistor R5. Reference numeral 22 denotes an on / off control circuit that controls the operation and stop of the amplifier 21 by the on / off control signal of the on / off control input terminal T24, and 23 is an abnormality detection circuit that detects an abnormality that has occurred in the amplifier 21. M21 is an open-drain type NMOS transistor connected between the abnormality diagnosis output terminal T25 and the ground, and is controlled by the abnormality detection circuit 23.

When the transistor M11 of the microcomputer 10 is controlled to be off, the on / off control output terminal T11 has a high impedance, and the on / off control input terminal T24 of the amplification device 20C is "H" by the pull-up resistor R1. The on / off control circuit 22 causes the amplifier 21 to operate normally.

When an abnormal operation such as an output voltage fluctuation, an output short circuit, an overload current, or an overheat occurs at time t1, the abnormality detection circuit 23 detects this abnormality and turns on the transistor M21. As a result, the abnormality diagnosis output terminal T25 pulled up by the resistor R5 is controlled to the abnormality diagnosis signal of "L", and the abnormality diagnosis signal of "L" is transmitted to the abnormality diagnosis input terminal T12 of the microcomputer 10.

On the side of the microcomputer 10, an abnormality diagnosis signal of “L” is taken into the buffer 11 from the abnormality diagnosis input terminal T12, and if it continues for a predetermined time, the internal circuit determines that an abnormality has occurred, and at the time tx. , The transistor M11 is controlled to be turned on, and the on / off control output terminal T11 is set to an “L” off control signal.

On the side of the amplifier 20C, when an abnormality diagnosis signal of "L" is input from the on / off control output terminal T11 to the on / off control input terminal T24, the amplifier 21 is controlled to the stopped state by the on / off control circuit 22. The amplifier 21 is protected.

By the way, in the amplification device, not only in the field of car electronics, improvement of component mounting density and cost reduction are naturally required. However, if the abnormality diagnosis output terminal T25 is specially provided as in the conventional amplification device 20C shown in FIG. 7, the number of terminals is increased contrary to the above requirement, the number of package terminals is increased, and the mounting area is increased. It will increase and lead to cost increase. In particular, amplifiers such as power amplifiers are often independent as single-function integrated circuits in terms of manufacturing process and thermal design, and packages with a small number of terminals are often selected, so there is a margin in the number of terminals. There is no. Due to such circumstances, there is a problem that it is unavoidable to give up mounting an abnormality diagnosis function, which is not the main function, on the amplification device.

In addition, for a small package amplification device that does not have enough terminals, it is not possible to install the above-mentioned abnormality diagnosis function that requires a new terminal, and the microcomputer that controls the operation and stop of the amplifier is the amplification device. There is no way to know the abnormality or failure of.

Therefore, conventionally, as shown in FIG. 9, the amplification device 20D is configured so as to provide the on / off control input / output terminal T23 that can be shared between the input of the on / off control signal and the output of the abnormality diagnosis signal. (Non-Patent Document 1). Then, the on / off control input / output terminal T23 is connected to the on / off control output terminal T21 connected to the CMOS output circuit 12 of the microcomputer 10B via the resistor R6, and is connected to the abnormality diagnosis input terminal T13. You are directly connected. Reference numeral 26 denotes a current source that is controlled to be turned on when the abnormality detecting circuit 23 detects an abnormality, and is connected between the on / off control input / output terminal T23 and the ground.

When the output of the CMOS output circuit 12 of the microcomputer 10B is an "H" on control signal, the on / off control input / output terminal T23 of the amplification device 20D is also an "H" on control signal, and the on / off control is performed. The circuit 22 allows the amplifier 21 to operate normally.

When an abnormality occurs at time t1, the abnormality detection circuit 23 detects it, turns on the current source 26, and draws a constant current ΔI from the on / off control input / output terminal T23 by the current source 26. At this time, the on / off control input / output terminal T23 drops by the voltage ΔV (= R6 × ΔI) determined by the resistance R6 and the current ΔI.

On the side of the microcomputer 10B, the decrease in the voltage ΔV is taken into the abnormality diagnosis input terminal T13 as an abnormality diagnosis signal. Then, when the voltage drop of only ΔV continues for a predetermined time, the output of the CMOS output circuit 12 is controlled to “L” off control and the on / off control output terminal T11 becomes an “L” off control signal at time tx. To do. As a result, in the amplification device 20D, the on / off control input / output terminal T23 becomes an “L” off control signal, and the operation of the amplifier 21 is stopped by the on / off control circuit 22.

In this way, in the amplification device 20D of FIG. 9, the on / off control input / output terminals T23 can be shared for the input of the on / off control signal and the output of the abnormality diagnosis signal, and the number of terminals of the amplification device 10D. We are trying to reduce.

Infineon Technologies, Catalog HITFET BTS133 Page8, May 19, 2000

However, in the conventional amplification device 20D described with reference to FIG. 9, the abnormality diagnosis input terminal T13 on the side of the microcomputer 10B is an analog input port, and is an A / D converter for detecting a minute voltage change ΔV inside the microcomputer 10B. There is a problem that it becomes necessary to provide 13 specially. Further, there is a problem that the voltage of the microcomputer is lowered and the minute voltage change ΔV cannot be large.

Here, _assuming that V DD is the power supply voltage of the microcomputer and V _1L is the “L” identification level in the specifications of the on / off control input / output terminal T23, the following equation must be satisfied.
V _DD −ΔV> V _1L (1)

Further, the "L" identification level of the on / off control input / output terminal T23 is designed to be higher than the specified value, and _{assuming that V 1L REAL} is the actual "L" identification level of the on / off control input / output terminal T23. , Equation (1) can be rewritten as Equation (2).
V _DD −ΔV> V _1LREAL > V _1L (2)

Therefore, if the low voltage operation of the microcomputer progresses and the power supply voltage V _DD decreases, it _{will approach V 1 LREAL,} and even if the relationship of the above equation (2) is maintained, "V _{DD −} ΔV" will be "V". _{If it is close to "1LREAL} ", there is a risk that the on / off control input / output terminal T23 may misrecognize the "L" level due to variations in the respective set voltages or mixing of noise, resulting in a minute voltage change ΔV. Will not be able to take a large amount.

An object of the present invention is to share an on / off control input / output terminal for inputting an on / off control signal of an amplifier and for outputting an abnormality diagnosis signal, while using an A / D converter or the like on the side of a control device such as a microcomputer. It is to provide an amplification device having an abnormality diagnosis function which makes it unnecessary.

In order to achieve the above object, the amplification device of the invention according to claim 1 stops an amplifier connected between a signal input terminal and a signal output terminal, an on-control signal for operating the amplifier, and the amplifier. An on / off control input / output terminal for inputting an on / off control signal composed of an off control signal for outputting an abnormality diagnosis signal and operating the amplifier based on the input of the on control signal. An on / off control circuit that stops the amplifier based on the input of the off control signal, an abnormality detection circuit that detects the presence or absence of an abnormality in the amplifier, and a latch that holds a signal sent to the on / off control circuit. The on / off control signal to be input to the on / off control input / output terminal is output to the on / off control circuit when the abnormality detection circuit does not detect an abnormality. Then, when the abnormality detection circuit detects an abnormality, the latch circuit latches the state in which the on control signal is output to the on / off control circuit, and the abnormality diagnosis signal is output from the on / off control input / output terminal. characterized in that and an abnormal operation when the control means alternates between a state in which the on / off control signal in a state to be outputted to the on / off control input terminal is input.

The invention according to claim 2 is the amplification device according to claim 1, which is switched between on-control signal output and off-control signal output, and outputs the on / off control signal to the on / off control input / output terminal. It has an on / off control output terminal and an abnormality diagnosis input terminal for inputting the abnormality diagnosis signal output from the on / off control input / output terminal, and determines the abnormality diagnosis signal input to the abnormality diagnosis input terminal. A control device for switching the signal of the on / off control output terminal from the on control signal output to the off control signal output is connected to the amplification device, and the on / off control output terminal of the control device is provided. Is switched off for the off control signal output, the amplifier is controlled off by the abnormal operation control means and the on / off control circuit.

The invention according to claim 3 is the amplification device according to claim 2, wherein the control device sets the on / off control output terminal to a high impedance for the on control signal output and a ground potential for the off control signal output. The abnormal operation control means includes an open drain transistor for switching to, and a first resistor for pulling up the on / off control input / output terminal and a first resistor connected between the on / off control input / output terminal and ground. comprising switch means, a timing generating circuit for controlling said latch circuit and said first switch means based on the presence or absence of abnormality before Symbol abnormality detection circuit detects said timing generating circuit, the abnormality detection circuit detects an abnormality A first timing for latching the on control signal generated in the on / off control input / output terminal by the latch circuit, a second timing for turning on the first switch means after the first timing, and the like. A third timing for turning off the first switch means after the second timing and a fourth timing for releasing the latch of the latch circuit after the third timing are generated, and the first to the first to the above after the fourth timing. By repeating the fourth timing, the state in which the abnormality diagnosis signal is output from the on / off control input / output terminal and the state in which the on / off control input / output terminal is opened and the on / off control signal is input can be obtained. It is characterized by repeating alternately.

The invention according to claim 4 is the amplification device according to claim 2, wherein the control device has a high impedance for the on control signal output and a ground potential for the off control signal output at the on / off control output terminal. The abnormal operation control means includes an open drain transistor for switching to, and a first resistor for pulling up the on / off control input / output terminal and a first resistor connected between the on / off control input / output terminal and ground. A common connection point between the switch means, the second switch means connected between the on / off control input / output terminal and the on / off control circuit, and the input side of the second switch means and the on / off control circuit. The first switch means and the timing generation circuit for controlling the second switch means based on the presence or absence of the abnormality detected by the abnormality detection circuit are provided, and the timing generation circuit includes the abnormality. The first timing for turning off the second switch means when the detection circuit detects an abnormality, the second timing for turning on the first switch means after the first timing, and the first switch after the second timing. By generating a third timing for turning off the means and a fourth timing for turning on the second switch means after the third timing, and repeating the first to fourth timings after the fourth timing, the said The state in which the abnormality diagnosis signal is output from the on / off control input / output terminal and the state in which the on / off control input / output terminal is opened and the on / off control signal is input are alternately repeated. ..

The invention according to claim 5 is the amplification device according to claim 2, wherein the control device sets the on / off control output terminal to a high impedance for the on control signal output and a ground potential for the off control signal output. An open-drain transistor for switching to is provided, and the abnormal operation control means is connected between a first resistor that pulls up the on / off control input / output terminal, and the on / off control input / output terminal and ground. A first switch means, a third resistor connected between the on / off control input / output terminal and the on / off control circuit, and a common connection between the third resistor and the input side of the on / off control circuit. A third switch means connected between the point and the positive power supply terminal and a timing generation circuit for controlling the first and third switch means based on the presence or absence of an abnormality detected by the abnormality detection circuit are provided, and the timing is provided. The generation circuit includes a first timing for turning on the third switch means when the abnormality detection circuit detects an abnormality, a second timing for turning on the first switch means after the first timing, and the second timing. A third timing for turning off the first switching means and a fourth timing for turning off the third switching means after the third timing are generated after the fourth timing, and the first to fourth timings are generated after the fourth timing. By repeating the above, the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the state of opening the on / off control input / output terminal and inputting the on / off control signal are alternately repeated. , Characterized by.

The invention according to claim 6 is the amplification device according to claim 2, wherein the control device provides a CMOS output circuit that switches the on / off control output terminal between the on control signal output and the off control signal output. The abnormal operation control means is provided between the fourth resistor connected between the on / off control output terminal and the on / off control input / output terminal, and between the on / off control input / output terminal and the ground. The connected first switch means, a latch circuit that can be switched between a latch that holds a signal sent from the on / off control input / output terminal to the on / off control circuit and an open that allows the signal to pass through, and the abnormality detection circuit. The first switch means and a timing generation circuit for controlling the latch circuit are provided based on the presence or absence of an abnormality detected by the timing generation circuit, and the timing generation circuit turns on / off control when the abnormality detection circuit detects an abnormality. The first timing for latching the on control signal generated in the output terminal by the latch circuit, the second timing for turning on the first switch means after the first timing, and the first timing after the second timing. By generating a third timing for turning off the switch means and a fourth timing for releasing the latch of the latch circuit after the third timing, and repeating the first to fourth timings after the fourth timing, The feature is that the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the state of opening the on / off control input / output terminal and inputting the on / off control signal are alternately repeated. To do.

The invention according to claim 7 is the amplification device according to any one of claims 2 to 6, wherein the control device inputs the abnormality diagnosis from the on / off control input / output terminal to the abnormality diagnosis input terminal. By counting a predetermined number of times the signal is repeated, the signal of the on / off control output terminal is switched from the on control signal output to the off control signal output.

The invention according to claim 8 is the amplification device according to any one of claims 2 to 6, wherein the control device inputs the abnormality diagnosis from the on / off control input / output terminal to the abnormality diagnosis input terminal. When the duration of signal repetition elapses for a predetermined time, the signal of the on / off control output terminal is switched from the on control signal output to the off control signal output.

According to the amplification device of the present invention, the on / off control input / output terminals can be shared for inputting the on / off control signal of the amplifier and for outputting the abnormality diagnosis signal when an abnormality occurs in the amplifier. , It is not necessary to provide a special output terminal for the abnormality diagnosis signal, and when an abnormality occurs, the on control signal and the abnormality diagnosis signal are repeated at the on / off control input / output terminals, and the repetition is "H", "L". It becomes a digital signal that repeats ". Therefore, it is not necessary to provide an A / D converter at the abnormality diagnosis input terminal of the control device. Therefore, there is an advantage that the safety and reliability of the built-in amplifier can be improved while avoiding an increase in the number of terminals and a cost increase in the package of the amplification device.

It is a block diagram of the control device and the amplification device of the 1st Example of this invention. It is a timing chart of the operation of the control device and the amplification device of the first embodiment of the present invention. It is a flowchart of operation of the control apparatus and amplification apparatus of 1st Embodiment of this invention. It is a block diagram of the control device and the amplification device of the 2nd Example of this invention. It is a block diagram of the control device and the amplification device of the 3rd Example of this invention. It is a block diagram of the control device and the amplification device of the 4th Example of this invention. It is a block diagram of a conventional control device and an amplification device. It is a timing chart of the operation of the control device and the amplification device of FIG. 7. It is a block diagram of another conventional control device and amplification device. It is a timing chart of the operation of the control device and the amplification device of FIG.

<First Example>
FIG. 1 is a block diagram showing a first embodiment of the present invention, showing an amplification device 20 having an abnormality diagnosis function in which the operation and stop of the amplifier 21 are controlled by a microcomputer (microcomputer) 10 as a control device.

In the microcomputer 10, M11 is an open-drain type NMOS transistor, the source is grounded, and the drain is connected to the on / off control output terminal T11. T12 is an abnormality diagnosis input terminal and is connected to an internal buffer 11. The on / off control output terminal T11 has a high impedance when it is used for on control signal output, and becomes “L” when it is used for off control signal output.

In the amplification device 20, T21 is a signal input terminal, T22 is a signal output terminal, and an amplifier 21 is connected between both terminals T21 and T22. T23 is an on / off control input / output terminal, and is connected to 10 on / off control output terminals T11 of the microcomputer and an abnormality diagnosis input terminal T12. R1 is a resistor for pulling up the on / off control input / output terminal T23, and may be built in the amplification device 20. M21 is an open-drain type NMOS transistor, the drain is connected to the on / off control input / output terminal T23, and the source is grounded. This transistor M21 constitutes the first switch SW1. Reference numeral 22 denotes an on / off control circuit that controls the operation (on) and stop (off) of the amplifier 21. Reference numeral 23 denotes an abnormality detection circuit, which outputs an abnormality detection signal when its own abnormal current, abnormal heat generation, output short circuit, or the like occurs during the operation of the amplifier 21.

Reference numeral 24 denotes a latch circuit, which is switched between a latch that holds a signal input from the on / off control input / output terminal T23 to the on / off control circuit 22 and an open that allows the signal to pass through. This latch circuit 24 latches the signal input to the D terminal when the signal of the C terminal becomes “L” during the period of “L” and outputs it from the Q terminal, and the signal of the C terminal becomes “H”. During the period of ", the signal input to the D terminal is passed as it is and output from the Q terminal.

Reference numeral 25 denotes a timing generation circuit, and when an abnormality detection signal is input from the abnormality detection circuit 23, a two-phase signal having a 180-degree phase difference that repeats H / L is output from the P1 terminal and the P2 terminal. The P1 terminal is connected to the C terminal of the latch circuit 24, and the P2 terminal is connected to the gate of the NMOS transistor M21.

In the context of the claims, the resistor R1, the transistor M21 (switch SW1), the latch circuit 24, and the timing generation circuit 25 constitute the abnormal operation control means.

Next, the operation of this embodiment will be described with reference to the timing chart of FIG. 2 and the flowchart of FIG. First, during normal operation, the transistor M11 of the microcomputer 10 is off, its drain is high impedance, and the on / off control input / output terminal T23 is lifted to the “H” on control signal by the resistor R1. ..

At this time, since the abnormality detection signal is not output from the abnormality detection circuit 23 (steps S1 and S2), the P1 terminal of the timing generation circuit 25 is “H” and the C terminal of the latch circuit 24 is “H” to latch. In the open state, the on / off control signal of “H” input to the on / off control input / output terminal T23 passes as it is and is input to the on / off control circuit 22, and the amplifier 21 is controlled to the operating state. ing. Further, since the P2 terminal of the timing generation circuit 25 is “L”, the transistor M21 is turned off.

When an abnormality occurs in the amplifier 21 operating normally as described above at time t1 and the abnormality detection circuit 23 that detects the abnormality generates an abnormality detection signal (step S2), the P1 terminal of the timing generation circuit 25 The signal goes down to "L", and the on / off control input / output terminal T23 "H" on control signal that the latch circuit 24 is inputting to the D terminal at that time is latched (step S3) and output to the Q terminal. However, the operating state of the amplifier 21 is maintained.

At time t2, the signal at the P2 terminal of the timing generation circuit 25 rises to “H”, so the transistor M21 is turned on and the signal at the on / off control input / output terminal T23 is changed from the “H” on control signal to “L”. "Abnormality diagnosis signal ("L "off control signal for inputting from the on / off control input / output terminal T23 of the amplification device 20 to the abnormality diagnosis input terminal T12 of the microcomputer 10" is described in this embodiment as described above. It is changed to "L" abnormality diagnosis signal "), and the abnormality diagnosis signal of" L "is input to the abnormality diagnosis input terminal T12 (step S4). At this time, since the latch circuit 24 is in the latch state, the Q terminal does not change from the “H” ON control signal, and the amplifier 21 is maintained in the operating state.

At time t3, the P2 terminal of the timing generation circuit 25 changes from “H” to “L”, so that the transistor M21 changes from on to off, and the on / off control input / output terminal T23 is pulled up by the resistor R1. And returns to the on control signal of "H". The abnormality diagnosis input terminal T12 also returns to the “H” ON control signal (step S5). At this time, since the P1 terminal of the timing generation circuit 25 continues to be “L”, it is in the latching state, the Q terminal remains the ON control signal of “H”, and the amplifier 21 is maintained in the operating state.

At time t4, the signal of the P1 terminal of the timing generation circuit 25 changes from “L” to “H”, so that the latch circuit 24 is switched to the latch open state (step S6), and the on / on / input to the D terminal is input. The on control signal of "H" of the off control input / output terminal T23 is passed through the Q terminal as it is, and the operating state of the amplifier 21 is maintained.

After the time t5, the same operation as the above-mentioned operations at the times t1 to t4 is repeated.

As described above, when an abnormality of the amplifier 21 is detected, the signal of the on / off control input / output terminal T23 repeats the on control signal of "H" and the abnormality diagnosis signal of "L", but the latch circuit 24 The Q terminal of is unchanged from the ON control signal of "H", and the amplifier 21 continues the operating state. At the abnormality diagnosis input terminal T12 of the microcomputer 10, a signal that repeats the “H” on control signal and the “L” abnormality diagnosis signal is taken into the inside from the buffer 11, and an edge that changes from “L” to “H” is formed. , The internal counter (not shown) is counted up.

Then, at the time tx when the count value of the counter reaches a preset value, the transistor M11 is controlled to be turned on. As a result, the on / off control output terminal T21 is controlled by the off control signal of “L” (steps S9 and S10). Therefore, the on / off control input / output terminal T23 of the amplification device 20 is forcibly turned into an “L” off control signal, and this signal passes through the latch circuit 24 in the latch open state to the on / off control circuit 22. Upon input, the amplifier 21 is controlled to stop operating (steps S7 and S8).

At this time, the microcomputer 10 notifies the error and records the error log (step S11), and recognizes the failure (step S12).

<Second Example>
FIG. 4 is a block diagram showing a second embodiment of the present invention, showing an amplification device 20A having an abnormality diagnosis function in which the operation and stop of the amplifier 21 are controlled by the microcomputer 10 as a control device. In the amplification device 20A of the present embodiment, instead of the latch circuit 24 in the amplification device 20 of FIG. 1, a second switch SW2 is connected between the on / off control input / output terminal T23 and the on / off control circuit 22. A pull-up resistor R2 is connected between the switch SW2, the common connection point of the on / off control circuit 22, and the positive power supply terminal + V. The switch SW2 is turned on when the P1 terminal of the timing generation circuit 25 is “H” and turned off when the timing generation circuit 25 is “L”. Others are the same as the amplification device 20 of FIG.

In relation to the claims, the resistors R1 and R2, the transistor M21, the switch SW2, and the timing generation circuit 25 constitute a control means at the time of abnormal operation.

During normal operation, the P1 terminal of the timing generation circuit 25 is “H”, so the switch SW2 is turned on, and the P2 terminal is “L”, so the transistor M21 is turned off. Therefore, the “H” on control signal pulled up by the resistors R1 and R2 is input to the on / off control circuit 22, and the amplifier 21 is controlled to the operating state.

When an abnormality of the amplifier 21 is detected by the abnormality detection circuit 23, the P1 terminal of the timing generation circuit 25 becomes “L”, the P2 terminal becomes “H”, and then the P2 terminal becomes “L”. The operation in which the P1 terminal becomes “H” (operations at times t1 to t4 in FIG. 2) is repeated.

Therefore, when an abnormality occurs at time t1 and the abnormality detection circuit 23 that detects the abnormality generates an abnormality detection signal, the signal of the P1 terminal of the timing generation circuit 25 falls to “L” and the switch SW2 is turned off. .. At this time, the ON control signal of “H” pulled up by the resistor R2 is input to the ON / OFF control circuit 22, and the operating state of the amplifier 21 is maintained.

At time t2, the signal of the P2 terminal of the timing generation circuit 25 rises to “H”, so that the transistor M21 is turned on and the signal of the on / off control input / output terminal T23 is changed from the “H” on control signal to “L”. The abnormality diagnosis signal of "L" is input to the abnormality diagnosis input terminal T12. Also at this time, the ON control signal of “H” pulled up by the resistor R2 is input to the ON / OFF control circuit 22, and the operating state of the amplifier 21 is maintained.

At time t3, the P2 terminal of the timing generation circuit 25 changes from “H” to “L”, so that the transistor M21 changes from on to off, and the on / off control input / output terminal T23 is pulled up by the resistor R1. And returns to the on control signal of "H". Similarly, the abnormality diagnosis input terminal T12 returns from the abnormality diagnosis signal of “L” to the ON control signal of “H”. Also at this time, the ON control signal of “H” pulled up by the resistor R2 is input to the ON / OFF control circuit 22, and the operating state of the amplifier 21 is maintained.

At time t4, the signal at the P1 terminal of the timing generation circuit 25 changes from “L” to “H”, so that the switch SW2 is turned on. Therefore, the ON control signal of “H” pulled up by the resistors R1 and R2 is input to the ON / OFF control circuit 22, and the amplifier 21 is maintained in the operating state.

After the time t5, the same operation as the above-mentioned operations at the times t1 to t4 is repeated. Other operations are the same as those of the first embodiment of FIG.

<Third Example>
FIG. 5 is a block diagram showing a third embodiment of the present invention, showing an amplification device 20B having an abnormality diagnosis function in which the operation and stop of the amplifier 21 are controlled by a microcomputer 10 as a control device. In the amplification device 20B of the present embodiment, instead of the latch circuit 24 in the amplification device 20 of FIG. 1, a resistor R3 is connected between the on / off control input / output terminal T23 and the on / off control circuit 22, and the resistor R3 is connected. The third switch SW3 is connected between the common connection point of R3 and the on / off control circuit 22 and the positive power supply terminal + V. The switch SW3 is turned off when the P1 terminal of the timing generation circuit 25 is “H” and turned on when the timing generation circuit 25 is “L”. Others are the same as the amplification device 20 of FIG.

In relation to the claims, the resistors R1 and R3, the transistor M21, the switch SW3, and the timing generation circuit 25 constitute a control means at the time of abnormal operation.

During normal operation, the P1 terminal of the timing generation circuit 25 is “H”, so the switch SW3 is turned off, and the on / off control input / output terminal T23 “H” on control signal is turned on via the resistor R3. The amplifier 21 is controlled to the operating state by inputting to the / off control circuit 22.

When an abnormality of the amplifier 21 is detected by the abnormality detection circuit 23, the P1 terminal of the timing generation circuit 25 becomes “L”, the P2 terminal becomes “H”, and then the P2 terminal becomes “L”. The operation in which the P1 terminal becomes “H” (operations at times t1 to T4 in FIG. 2) is repeated.

Therefore, when an abnormality occurs at time t1 and the abnormality detection circuit 23 that detects the abnormality generates an abnormality detection signal, the signal of the P1 terminal of the timing generation circuit 25 falls to “L” and the switch SW3 is turned on. , The ON control signal of “H” is input to the ON / OFF control circuit 22 by the switch SW3, and the operating state of the amplifier 21 is maintained.

At time t2, the signal of the P2 terminal of the timing generation circuit 25 rises to “H”, so that the transistor M21 is turned on and the signal of the on / off control input / output terminal T23 is changed from the “H” on control signal to “L”. The abnormality diagnosis signal of "L" is input to the abnormality diagnosis input terminal T12. Also at this time, the ON control signal of “H” is input to the ON / OFF control circuit 22 by the switch SW3, and the operating state of the amplifier 21 is maintained.

At time t3, the P2 terminal of the timing generation circuit 25 changes from “H” to “L”, so that the transistor M21 changes from on to off, and the on / off control input / output terminal T23 is pulled up by the resistor R1. And returns to the on control signal of "H". Similarly, the abnormality diagnosis input terminal T12 returns from the abnormality diagnosis signal of “L” to the ON control signal of “H”. At this time, the ON control signal of “H” is input to the ON / OFF control circuit 22 by the switch SW3, and the operating state of the amplifier 21 is maintained.

At time t4, the signal at the P1 terminal of the timing generation circuit 25 changes from “L” to “H”, so that the switch SW3 is turned off, but the on / off control input / output terminal T23 “H” on control signal is turned off. Since the input is input to the on / off control circuit 22, the operating state of the amplifier 21 is maintained.

After the time t5, the same operation as the above-mentioned operations at the times t1 to t4 is repeated. Other operations are the same as those of the first embodiment.

<Fourth Example>
FIG. 6 is a block diagram showing a fourth embodiment of the present invention, showing an amplification device 20 having an abnormality diagnosis function in which the operation and stop of the amplifier 21 are controlled by the microcomputer 10A as a control device. In the microcomputer 10A of this embodiment, the microcomputer 10A that controls the potential of the on / off control output terminal T11 to the “H” on control signal and the “L” off control signal by the CMOS output circuit 12 is used. Further, instead of the pull-up resistor R1, a resistor R4 is connected between the on / off control output terminal T11 of the microcomputer 10A and the on / off control input / output terminal T23 of the amplification device 20. The on / off control output terminal T11 of the control circuit 10A is "H" when it is for on control signal output, and is "L" when it is for off control signal output.

In the context of the claims, the resistor R4, the transistor M21, the latch circuit 24, and the timing generation circuit 25 constitute a control means at the time of abnormal operation.

During normal operation, the output of the CMOS output circuit 12 of the microcomputer 10A is set to the “H” on control signal, and the signal is input to the on / off control input / output terminal T23 of the amplification device 20. At this time, since the P1 terminal of the timing generation circuit 25 is “H”, the ON control signal of “H” of the on / off control output terminal T21 passes through the latch circuit 24 in the unlatched state and is turned on / off control circuit 22. The amplifier 21 is controlled to the operating state by inputting to.

When an abnormality of the amplifier 21 is detected by the abnormality detection circuit 23, the P1 terminal of the timing generation circuit 25 becomes “L”, the P2 terminal becomes “H”, and then the P2 terminal becomes “L”. The operation in which the P1 terminal becomes “H” (operations at times t1 to T4 in FIG. 2) is repeated.

Therefore, when an abnormality occurs at time t1 and the abnormality detection circuit 23 that detects the abnormality generates an abnormality detection signal, the signal of the P1 terminal of the timing generation circuit 25 falls to “L”, and the latch circuit 24 at that time. The on / off control input / output terminal T23 "H" on control signal input to the D terminal is latched and output to the Q terminal, and the operating state of the amplifier 21 is maintained.

At time t2, the signal of the P2 terminal of the timing generation circuit 25 rises to “H”, so that the transistor M21 is turned on and the signal of the on / off control input / output terminal T23 is changed from the “H” on control signal to “L”. The abnormality diagnosis signal of "L" is input to the abnormality diagnosis input terminal T12 of the microcomputer 10A. At this time, the latch circuit 24 is in the latched state, the Q terminal does not change from the “H” ON control signal, and the amplifier 21 is maintained in the operating state.

At time t3, the P2 terminal of the timing generation circuit 25 changes from “H” to “L”, so that the transistor M21 changes from on to off, and the on / off control input / output terminal T23 has a resistor R4 of the microcomputer 10A. The on-control signal of "H" via is input. Similarly, the abnormality diagnosis input terminal T12 returns from the abnormality diagnosis signal of “L” to the ON control signal of “H”. At this time, since the P1 terminal of the timing generation circuit 25 continues to be “L”, it is in the latching state, the Q terminal remains the ON control signal of “H”, and the amplifier 21 is maintained in the operating state.

At time t4, the signal of the P1 terminal of the timing generation circuit 25 changes from “L” to “H”, so that the latch circuit 24 switches to the latch open state, and the on / off control input / output input to the D terminal is input. The ON control signal of "H" of the terminal T23 is passed through the Q terminal as it is, and the operating state of the amplifier 21 is maintained.

After the time t5, the same operation as the above-mentioned operations at the times t1 to t4 is repeated. Other operations are the same as those of the first embodiment.

<Other Examples>
In the first to fourth embodiments described above, when an abnormality occurs in the amplifier 21, an “L” abnormality diagnosis signal input to the abnormality diagnosis input terminal T12 of the microcomputer 10 or the abnormality diagnosis input terminal T13 of the microcomputer 10A Counting the number of repetitions of the "H" on control signal with a counter, the transistor M11 is turned on, or the output of the CMOS output circuit 12 is controlled to "L", and the on / off control output terminal T11 is set to "L". I tried to control to the off control signal of, but it is not limited to this.

For example, after the abnormality diagnosis signal of "L" repeatedly input to the abnormality diagnosis input terminal T12 becomes "L" for the first time, "L" and "H" are repeated even after a predetermined time set by the timer has elapsed. If this is the case, the on / off control output terminal T11 may be controlled to an “L” off control signal.

10, 10A, 10B: Microcomputer (control device), 11: Buffer, 12: CMOS output circuit, 13: A / D converter, T11: On / off control output terminal, T12, T13: Abnormality diagnosis input terminal 20, 20A, 20B, 20C, 20D: Amplifier, 21: Amplifier, 22: On / Off control circuit, 23; Abnormality detection circuit, 24: Latch circuit, 25: Timing generation circuit, 26: Current source, T21: Signal input terminal, T22 : Signal output terminal, T23: On / off control input / output terminal, T24: On / off control input terminal, T25: On / off control output terminal

Claims (8)

An on / off control signal consisting of an amplifier connected between the signal input terminal and the signal output terminal, an on control signal for operating the amplifier, and an off control signal for stopping the amplifier is input, and an abnormality diagnosis is performed. An on / off control input / output terminal for outputting a signal, and an on / off control circuit that operates the amplifier based on the input of the on control signal and stops the amplifier based on the input of the off control signal. The abnormality detection circuit includes an abnormality detection circuit that detects the presence or absence of an abnormality in the amplifier, and a latch circuit that can be switched between a latch that holds a signal sent to the on / off control circuit and an open that allows the signal to pass through. Is not detected, the on / off control signal to be input to the on / off control input / output terminal is output to the on / off control circuit, and when the abnormality detection circuit detects an abnormality, the latch circuit is turned on. The state of outputting the on control signal to the / off control circuit and the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the on / off control signal to the on / off control input / output terminal. An amplification device including an abnormal operation control means that alternately repeats a state in which is input. In the amplification device according to claim 1,
An on / off control output terminal that is switched between an on control signal output and an off control signal output and outputs the on / off control signal to the on / off control input / output terminal, and an output from the on / off control input / output terminal. It has an abnormality diagnosis input terminal for inputting the abnormality diagnosis signal, and by determining the abnormality diagnosis signal input to the abnormality diagnosis input terminal, the signal of the on / off control output terminal is used for the on control signal output. A control device for switching from to the off control signal output is provided by connecting to the amplification device.
When the on / off control output terminal of the control device is switched for the off control signal output, the amplifier is controlled to be off by the abnormal operation control means and the on / off control circuit. Amplification device. In the amplification device according to claim 2,
The control device includes an open drain transistor that switches the on / off control output terminal between a high impedance for the on control signal output and a ground potential for the off control signal output.
The abnormal operation time control means comprises: a first resistor for pulling up the ON / OFF control input and output terminals, the on / off control input terminal and a first switch means connected between the ground, before Symbol abnormality detection A timing generation circuit for controlling the first switch means and the latch circuit based on the presence or absence of an abnormality detected by the circuit is provided.
The timing generation circuit has a first timing in which the on control signal generated in the on / off control input / output terminal when the abnormality detection circuit detects an abnormality is latched by the latch circuit, and after the first timing. A second timing for turning on the first switch means, a third timing for turning off the first switch means after the second timing, and a fourth timing for releasing the latch of the latch circuit after the third timing. Is generated, and the first to fourth timings are repeated after the fourth timing to open the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the on / off control input / output terminal. The state in which the on / off control signal is input is repeated alternately.
Amplification device characterized by that. In the amplification device according to claim 2,
The control device includes an open drain transistor that switches the on / off control output terminal between a high impedance for the on control signal output and a ground potential for the off control signal output.
The abnormal operation control means includes a first resistor that pulls up the on / off control input / output terminal, a first switch means that is connected between the on / off control input / output terminal and the ground, and the on / off. A second switch means connected between the control input / output terminal and the on / off control circuit, and a second resistor that pulls up a common connection point between the second switch means and the input side of the on / off control circuit. A timing generation circuit for controlling the first switch means and the second switch means based on the presence or absence of an abnormality detected by the abnormality detection circuit is provided.
The timing generation circuit includes a first timing for turning off the second switch means when the abnormality detection circuit detects an abnormality, a second timing for turning on the first switch means after the first timing, and the first timing. A third timing for turning off the first switch means after the second timing and a fourth timing for turning on the second switch means after the third timing are generated, and the first to first steps are generated after the fourth timing. By repeating the four timings, the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the state of opening the on / off control input / output terminal and inputting the on / off control signal are alternated. Repeat to
Amplification device characterized by that. In the amplification device according to claim 2,
The control device includes an open drain transistor that switches the on / off control output terminal between a high impedance for the on control signal output and a ground potential for the off control signal output.
The abnormal operation control means includes a first resistor that pulls up the on / off control input / output terminal, a first switch means connected between the on / off control input / output terminal and ground, and the on. Between the third resistor connected between the / off control input / output terminal and the on / off control circuit, the common connection point between the third resistor and the input side of the on / off control circuit, and the positive power supply terminal. A third switch means connected to the above and a timing generation circuit for controlling the first and third switch means based on the presence or absence of an abnormality detected by the abnormality detection circuit.
The timing generation circuit includes a first timing for turning on the third switch means when the abnormality detection circuit detects an abnormality, a second timing for turning on the first switch means after the first timing, and the first timing. A third timing for turning off the first switch means after the second timing and a fourth timing for turning off the third switch means after the third timing are generated, and the first to first steps are generated after the fourth timing. By repeating the four timings, the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the state of opening the on / off control input / output terminal and inputting the on / off control signal are alternated. Repeat to
Amplification device characterized by that. In the amplification device according to claim 2,
The control device includes a CMOS output circuit that switches the on / off control output terminal between the on control signal output and the off control signal output.
The abnormal operation control means is connected between a fourth resistor connected between the on / off control output terminal and the on / off control input / output terminal, and between the on / off control input / output terminal and ground. The first switch means, a latch circuit that can be switched between a latch that holds a signal sent from the on / off control input / output terminal to the on / off control circuit, and an open that allows the signal to pass through, and the abnormality detection circuit detect the abnormality. The first switch means and the timing generation circuit for controlling the latch circuit are provided based on the presence or absence of an abnormality.
The timing generation circuit has a first timing in which the on control signal generated in the on / off control input / output terminal when the abnormality detection circuit detects an abnormality is latched by the latch circuit, and after the first timing. A second timing for turning on the first switch means, a third timing for turning off the first switch means after the second timing, and a fourth timing for releasing the latch of the latch circuit after the third timing. Is generated, and the first to fourth timings are repeated after the fourth timing to open the state of outputting the abnormality diagnosis signal from the on / off control input / output terminal and the on / off control input / output terminal. The state in which the on / off control signal is input is repeated alternately.
Amplification device characterized by that. In the amplification device according to any one of claims 2 to 6.
The control device counts a predetermined number of repetitions of the abnormality diagnosis signal input from the on / off control input / output terminal to the abnormality diagnosis input terminal, thereby generating a signal output from the on / off control output terminal. An amplification device characterized by switching from the on control signal to the off control signal. In the amplification device according to any one of claims 2 to 6.
The control device is output from the on / off control output terminal when a predetermined time elapses for the duration of repetition of the abnormality diagnosis signal input from the on / off control input / output terminal to the abnormality diagnosis input terminal. An amplification device, characterized in that the signal is switched from the on control signal to the off control signal.

Images