JP2005327949A - Solenoid driving integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when a plurality of solenoid valves are simultaneously driven in a solenoid driving circuit for driving solenoid coils of the solenoid valves or the like, formation of the circuit in the form of an integrated LSI causes an LSI cost to be increased by an increase in the number of control terminals, or causes the operational load of a controlling microcomputer to be increased by the simultaneous driving of the plural solenoid valves. <P>SOLUTION: A solenoid driving integrated circuit comprises a switching element for turning ON and OFF a current, a resistor and a current detection circuit for detecting the current, and a comparison means for comparing a current amount. The integrated circuit also comprises a means for holding data inputted from a microcomputer, means for calculating the data held in the holding means, and a means for converting an output of the calculating means to an analog signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solenoid coil drive circuit for controlling the amount of current flowing in a solenoid coil used for driving an electromagnetic actuator or the like, and further relates to a solenoid drive integrated circuit in which this is integrated on a silicon wafer.

  In recent engine control, various technologies have been introduced for the purpose of tightening exhaust gas regulations and improving fuel efficiency.

  One of them is VTC (Valve Timing Control) technology. This varies the timing of intake / exhaust valves, etc. according to the engine speed. Generally, an electric actuator using a solenoid coil, such as a solenoid valve, is used. Control is driven by controlling.

  According to this current amount control, as shown in Patent Document 1, a current detection circuit such as a resistor that detects the amount of current flowing in the coil, a current amount detected by the resistor, and a set current value, It is driven by a circuit constituted by a duty control circuit for controlling the duty and a switch element such as a transistor driven by the controlled pulse. For the duty control, in addition to the method of determining the duty using a sawtooth wave based on the voltage fed back as in the known example, a PWM control function built in a control device such as a microcomputer in recent years is used. There is also a control method.

  In recent years, in order to reduce the size and cost of a control unit for mounting a circuit, the above control circuit is often configured as an integrated circuit on a silicon wafer and used as an LSI.

JP 7-293732 A

  Engine control that improves the fuel efficiency by varying the intake and exhaust valve timings, such as the above-mentioned VCT, is often adopted for engines having a large displacement such as V-type engines.

  In this case, there are a total of four solenoid valves that perform control, including intake and exhaust, and it is necessary to drive four solenoid coils simultaneously.

  When there are multiple solenoid valves to be driven, an integrated circuit is often used to reduce the mounting area and cost, but in the known example, when there are multiple drive circuits, a control terminal is provided for each solenoid valve. There is a problem that the number of terminals and the size of the peripheral control circuit are increased because the control unit must be controlled for each drive circuit. In addition, since the control signal must be continuously supplied from the control unit, the operation load of the control unit is large, and it is difficult to cope with a plurality of solenoid valves to be driven.

  Further, in the case of the publicly known example, since the amount of current actually flowing is not fed back to the control unit for performing the control, for example, it is not possible to cope with the control of the amount of current by the PWM control method using a microcontroller. If the current amount detection signal is fed back to the control unit, an additional terminal is required, and there is a problem that it is more difficult to make an integrated circuit.

  In addition, when driving a plurality of solenoid valves as in the case of VCT control, for example, when one solenoid valve is stopped, each solenoid valve operates at different timings such as moving another solenoid valve. When a drive signal is supplied from the control unit to each solenoid valve as in a known example, control is always performed while continuously applying a control voltage. Therefore, when a circuit is integrated on the same wafer, one solenoid It is also conceivable that noise is generated by the current flowing by driving the valve, causing disturbance to other solenoid valves that are operating separately, and having an adverse effect such as malfunction.

  In order to solve the above problems, a holding unit that holds data from a control unit such as an external microcomputer, a calculation unit that calculates the held data, and a conversion unit that converts the output of the calculation unit into analog data And a comparison means for comparing the signal output from the conversion means with the output signal of the current detection circuit.

  In addition, in the case where control is performed by directly turning on / off the switching means by a control signal from a control means such as a microcomputer, the data conversion means for converting the signal output from the current detection circuit into digital data, and the digital data This can be realized by a configuration in which an output means for sending the signal to the control means is provided.

  According to the present invention, even when the number of solenoid valves to be driven increases, a plurality of solenoid valves can be driven simultaneously without increasing the operation load of the microcomputer for controlling the number of terminals, the peripheral circuit scale, and the drive current amount. In addition, it is possible to realize a solenoid drive integrated circuit that is not adversely affected by operation noise of other solenoid coils and can appropriately cope with an abnormal operation such as an overcurrent.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing an example of a solenoid valve driving circuit for explaining a first embodiment of the present invention.

  In FIG. 1, reference numerals 1 and 51 denote drive circuits for driving one solenoid valve. Reference numerals 2 and 52 denote holding means for holding data input from the microcomputer, reference numerals 3 and 53 denote arithmetic means for performing arithmetic processing on the data from the holding means 2, and reference numerals 4 and 54 denote arithmetic outputs from the arithmetic means 3. Outputs 5, 55 are comparison means, 8 and 58 are comparison outputs, 10 and 60 are AND circuits, 11 and 61 are buffer circuits that drive switching elements that conduct and cut off current, and 12 and 62 are high switching elements. Side MOS. Similarly, reference numerals 13 and 63 denote low-side MOSs that perform current switching, reference numerals 14 and 64 denote current detection resistors for detecting current flowing through coils in the solenoid valve, reference numerals 15 and 65 denote solenoid valves, and reference numerals 16, 17, 66, and 67 denote current detection. This is a current detection voltage detected by the resistors 14 and 64 and varies according to the amount of current flowing through the solenoid valves 15 and 65. Reference numerals 18 and 68 denote flywheel diodes, reference numerals 19 and 69 denote current detection circuits, and reference numerals 20 and 70 denote current amount signals output from the current detection means. Reference numerals 21 and 71 denote analog conversion means for converting the calculation outputs 4 and 54 from the calculation means 3 and 53 into analog calculation signals 23 and 73, respectively. Reference numerals 24 and 74 denote 0 detecting means for detecting whether or not the data held in the holding means is zero, 25 and 75 are the current setting value a, 26 and 76 are the current setting value b, and 22 and 72 are the high side. MOS drive signals, 27 and 77 are low-side MOS drive signals, 31 and 81 are the amount of current actually flowing through the solenoid valve coil, 32 and 82 are zero detection signals, and 43 and 93 are gate drive signals that drive the high-side MOS. is there.

  Reference numeral 100 denotes an LSI in which the above circuits are integrated, and reference numerals 102 and 104 denote holding data input from a microcomputer. Reference numeral 105 denotes communication means for exchanging data between the microcomputer 106 and the LSI 100, and reference numeral 107 denotes a communication signal for communication.

  FIG. 2 shows the configuration of the holding means 2 and 52. In FIG. 2, 2a (52a) is a current set value a holding register circuit, 2b (52b) is a current set value b holding register circuit, 2c (52c) is a high side MOS drive signal holding register circuit, and 2d (52d) is a low side. This is a MOS drive signal holding register circuit.

  FIG. 3 shows the configuration of the calculation means 3 and 53 in FIG.

  In FIG. 3, reference numeral 3a (53a) denotes an arithmetic circuit, which performs operations such as addition and subtraction of input held data. Reference numeral 3b (53b) denotes a changeover switch 1, which switches between the 3c (53c) side and the 3d (53d) side according to the output of the comparison output 8 (58) in FIG. 3e (53e) is a change-over switch 2 that switches between the 3f (53f) side and the 3g (53g) side according to the output signal 32 (82) of the zero detecting means 24 (74). 3h (53h) is a minimum ripple value generation circuit. When the current set value b is zero, a predetermined minimum ripple value is sent to the arithmetic circuit 3a via the change-over switch 2 according to the output 32 of the zero detection means 24. It is done.

  FIG. 4 is a block diagram showing the configuration of the 0 detecting means 24 (74) in FIG. In FIG. 4, 2a (74a) denotes an AND circuit, and 24b (74b) to 24d (74d) denote inverting buffers, which are connected in the same number as the number of data bits of the set current value b.

  Next, the solenoid valve driving operation in the present embodiment will be described with reference to FIGS.

In the solenoid drive circuit 1, data of the set current values a and b are sent from the microcomputer 106 via the communication means 105 and are held in the register circuits 2 a and 2 b in the holding means 2. At the same time, the high-side and low-side MOS drive signals 22 and 27 are also held in the register circuits 2c and 2d in the holding means 2. As shown in FIG. 5, the register circuit 2c,
When the setting of 2d becomes high, the AND gate 10 is opened, the high side MOS 12 is ready for driving, and the low side MOS 13 is turned on.

When the set current value a of the holding unit 2 is zero, the calculation unit 3 calculates (current set value a−current set value b), and the calculation output 4 becomes zero. The calculation output 4 is input to the analog conversion means 21, converted to an analog calculation signal 23 corresponding to the calculation output data value, and input to the comparison means 5. The comparison means 5 compares the analog operation signal 23 with the current amount signal 20 output from the current detection circuit 19 and outputs a comparison output 8. At this time, as shown in FIG. 5, when (analog calculation signal 23> current amount signal 20) is established, high is output, so when the calculation output is zero, the comparison output 8 remains low, The high side MOS 12 is not driven. At this time, since the comparison output 8 of the comparison means is also input to the calculation means 3, the switch circuit 3b is switched to the terminal 3c side, and the current setting value a (25) is output to the calculation output 4. ing.

  As shown in FIG. 5, when A is set for the set current value a and C is set for the set current value b, the following operation is performed. First, since the switch 3b is switched to the terminal 3c side in the calculation means 3, the current setting value A is output to the calculation output 4. This current set value A is input to the analog conversion means 21, and an analog calculation signal 23 corresponding to the set value A is output. In this case, (analog calculation signal 23> current amount signal 20) is established, and therefore, as shown in FIG. As a result, the comparison output 8 becomes high, the high-side MOS is turned on by the gate drive signal 43, and the drive current 31 of the solenoid valve increases as shown in FIG.

  Since the drive current 31 also flows through the current detection resistor 14 connected in series with the solenoid valve 15, current detection voltages 16 and 17 are generated at both ends of the resistor 14. The current detection circuit 19 detects the amount of current actually driven from the detection voltages 16 and 17, and outputs a current amount signal 20 that changes according to the amount of current flowing through the solenoid valve 15, as shown in FIG. This current amount signal 20 is input to the comparison means 5 and compared with the analog operation signal 23.

  As a result, as shown in FIG. 5, when the drive current 31 reaches A, the comparison output 8 of the comparison means 5 becomes low, the high-side MOS 12 is turned off, and the drive current 31 decreases.

At the same time, when the comparison output 8 goes low, the switch circuit 3b of the computing means 3 is switched to the terminal 3d side. At this time, the current set value b is the predetermined amount C, and the calculation means 3 calculates (current set value a−current set value b), so that the calculation output 4 is (AC) with respect to the predetermined amount A. ) Value.

The drive current 31 that has decreased due to the high-side MOS 12 being turned off is detected by the current detection means 19, converted into a current amount signal 20, and similarly compared by the comparison means 5. When the current amount signal 20 decreases to the signal level of the analog calculation signal 23 corresponding to the (AC) value that is the output of the calculation means 3, the comparison means 5 outputs high again to turn on the high side MOS 12. Therefore, the drive current 31 starts to increase.

  By repeating this operation, the drive current 31 continues to flow at a constant amount while maintaining the ripple width of C with the set value A as the upper limit as shown in FIG. 5, and the solenoid valve is driven according to this current value. Become.

  For example, even when the set current value b (26) of the holding unit 2 is rewritten to a predetermined amount D from the microcomputer 106 via the communication unit 105, the same operation as described above is performed as shown in FIG. A current flows while maintaining the ripple width D, and the solenoid valve can be driven. Similarly, when the set current value a25 is varied, if the data of the set current value a held in the holding means 2 is rewritten to a predetermined amount B, the drive current decreases to B while maintaining the ripple width D, The solenoid valve is driven according to this amount of current.

  Thereby, according to the data held in the holding means 2, the current amount and the ripple amount are automatically adjusted, and the solenoid valve is driven according to the current amount, so the user rewrites the data in the holding means 2. The target solenoid valve drive control can be performed only by this.

  The above description only describes the operation of the drive circuit 1 in the embodiment shown in FIG. 1, but the drive circuit 51 is exactly the same, and the current amount is determined according to the current value data set in the holding means 52. Can be controlled to drive the solenoid valve 65.

  The same applies to the case where a plurality of solenoid valves are driven, and the microcomputer 106 automatically rewrites the set value data of the current held in the holding means for each drive circuit for each drive circuit. In addition, a desired amount of current can be applied and the solenoid valve can be driven independently.

  Therefore, the microcomputer can drive the solenoid valve for each individual by simply communicating with the LSI 100 and setting desired current amount data in advance for each drive circuit. After that, only when it is necessary to change the amount of current, it is only necessary to communicate with the LSI 100 to rewrite the data in the holding means, so there is no need to always provide data, and the operating load of the control means such as a microcomputer Does not adversely affect other controls. Therefore, according to this embodiment, even when a plurality of solenoid valves are driven, they can be easily driven.

  In addition, since the data of the holding means is rewritten from the microcomputer and the current is controlled by feedback inside the integrated circuit with this data, it is not always necessary to continuously give a control signal, and it is less affected by external noise and the like. . Therefore, it is possible to provide a solenoid drive integrated circuit that is less susceptible to the drive operation of other solenoid valves even when a plurality of drive circuits are driven simultaneously.

  The embodiment of FIG. 1 also has the following effects.

  FIG. 4 is a block diagram showing the configuration of the 0 detecting means 24 in FIG. In FIG. 4, 24a is an AND gate, and 24b to 24d are inverting buffers, which are connected in the same number as the number of data bits of the set current value a. Therefore, when all the bits of the input signal 26 are 0, the zero detection signal 32 is output.

  The zero detecting means 24 has the following effects.

  In this embodiment, predetermined data is held in the holding means 2 by the current set value data 25 and 26, and the current amount is controlled by this. Further, the retained data is zero immediately after the power is turned on or until a predetermined amount of set current values a and b are set by the microcomputer after the power is turned on.

  When a predetermined value A is set as the set current value a in this state, the high-side MOS 12 is turned on as described above, the drive current 31 flows and rises until the predetermined value A is reached. Output becomes low, and the high-side MOS 12 is turned off. At this time, if the current set value b is 0, the output of the 0 detection means 24 is high, the zero detection signal 32 is input to the calculation means 3, and the switch circuit 3e is switched to the terminal 3g side. Therefore, even when the current set value b is zero, the predetermined minimum ripple value 3h is given to the arithmetic circuit 3a, and the output of the arithmetic means 3 is calculated with respect to A by (A−minimum ripple value 3h). As a result, the drive current 31 decreases as shown in FIG.

  The lowered drive current 31 is similarly detected by the current detection circuit 19 and compared by the comparison means 5. When the drive current 31 is reduced to (A-minimum ripple value 3h), the comparison means 5 again outputs high and turns on the high-side MOS 12, so that the drive current 31 increases again.

  Thereafter, this operation is repeated, and the drive current 31 continues to flow in a constant amount while maintaining the ripple width of the minimum ripple value 3h as shown in FIG. 5, and the solenoid valve is driven according to this current value.

  As a result, even if the data of the current set value b is zero, a predetermined amount of the minimum ripple value 3h is automatically supplied. Therefore, since the ripple width of at least the predetermined amount 3h is given to the comparison means 5, the ripple width becomes 0, the oscillation phenomenon of the comparison means 5 occurs, and there arises a problem that problems such as high-side MOS switching noise occur. A solenoid drive integrated circuit can be realized.

  FIG. 6 is a block diagram showing an example of a solenoid valve drive circuit for explaining the second embodiment of the present invention.

6, 9 and 59 are switch circuits 1, 30 and 80 for switching between the external input signals 29 and 79 and the internal signals 8 and 58, conversion means for converting the current amount signals 20 and 70 into data,
Reference numerals 101 and 103 denote current value data outputs output from the conversion means 30 and 70 in each solenoid valve drive circuit, and are input to the communication means 105 that communicates with the microcomputer 106.

  The external input signals 29 and 79 are connected to PWM control signals 110 and 111 via terminals of the LSI 100. The PWM control signal is output from the microcomputer 106. FIG. 7 is a block diagram showing the configuration of the holding means 2 and 52 in FIG. Reference numerals 2e and 52e denote switch control signal holding circuits, which can perform switching control of the switch circuit 1. Other than this, the second embodiment is the same as the first embodiment.

  Next, the operation of this embodiment will be described with reference to FIG.

As in the first embodiment, the high side MOS drive signal 22 written from the microcomputer to the holding means is in the drive ready state, and the low side MOS drive signal 27 turns on the low side MOS 13. In this state, when the PWM control signal 110 is input from the microcomputer 106, the high-side MOS 12 is turned on and the drive current 31 flows as shown in FIG. 8, and the amount of this current is detected by the detection resistor 14 and the current detection means 19. Current amount signal 20 is output and converted to current value data 101 by data converter 30. The converted current value data 101 is sent to the microcomputer 106 via the communication means 105. The microcomputer determines the duty of the PWM control signal 110 based on the current value data, and the amount of current flowing through the solenoid valve. The PWM control signal 110 for driving the high-side MOS 12 can be output so that becomes constant.

  As described above, the switch circuits 9 and 59 for inputting the external signal, the conversion means 30 and 80 for converting the current value data, and the communication circuit for transferring the data to the microcomputer are provided. The solenoid valve is switched between the current control method based on the current set value data held in the holding means 2 as described in the first embodiment and the PWM drive control method using an external microcomputer as shown in the second embodiment. Therefore, it is possible to provide a solenoid driving integrated circuit that can cope with different driving systems by one solenoid driving integrated circuit.

  FIG. 9 shows a third embodiment in which latch means 35 and 38 and abnormality detection means 33 and 83 are added. The operation is shown in FIG.

  According to the present invention, the integrated circuit can be used in a control unit such as a VCT that simultaneously drives a plurality of solenoid valves.

  In addition, the drive integrated circuit having the present invention can be used for a control unit designed by a conventional PWM control method using a microcomputer.

1 is a circuit block diagram illustrating a first embodiment of the present invention. The block diagram explaining the structure of the holding means 2 shown in FIG. The block diagram explaining the structure of the calculating means 3 shown in FIG. The block diagram explaining the structure of the zero detection means 24 shown in FIG. The timing chart explaining operation | movement of 1st Example. The circuit block diagram explaining the 2nd example of the present invention. The block diagram explaining the structure of the holding means 2 shown in FIG. The timing chart explaining operation | movement of 2nd Example. The circuit block diagram which shows a 3rd Example. The figure which shows the timing chart of a 3rd Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solenoid drive circuit, 2 ... Holding means, 3 ... Calculation means, 4 ... Calculation output, 5 ... Comparison means, 8 ... Comparison output, 10 ... AND circuit, 11 ... Buffer circuit, 12 ... High side MOS

Claims (5)

In a solenoid integrated circuit comprising: current switching means for controlling current interruption / conduction; current detection means for detecting current flowing to the solenoid coil; and drive means for driving the current switching means.
Given a current command value indicating the amount of current flowing from the control device to the solenoid coil,
Holding means for holding the current command value;
Comparing means for comparing the held value with the amount of current flowing through the solenoid coil,
A solenoid drive integrated circuit comprising control means for controlling the amount of current flowing through the solenoid coil in accordance with a comparison result of the comparison means. In claim 1,
A solenoid drive integrated circuit comprising a conversion means for converting the output of the holding means for holding the current command value given by the control device into a digital signal by serial or parallel communication and converting it into an analog signal. In claim 1 or 2,
Furthermore, it comprises a plurality of holding means and a plurality of analog signal conversion means,
The current command value given by the control device is held in a plurality of holding means simultaneously with digital signals by serial or parallel communication,
A solenoid driving integrated circuit characterized by simultaneously driving a plurality of solenoid coils individually. In any one of Claims 1-3,
Furthermore, it has a calculation means for calculating the data held in the general holding means, and a zero detection means for detecting that it is zero,
A solenoid drive integrated circuit, comprising: a calculation means for adding and outputting a predetermined value other than 0 when the data outputted from the holding means is zero. In any one of Claims 1-3,
Furthermore, a changeover switch means for switching the output of the comparison means and the input signal from the external control device, and an output means for outputting the output of the data conversion means to the external control device,
A solenoid drive integrated circuit characterized in that on / off control of the current switching means is performed by a control signal output from an external control device in accordance with an output of the data conversion means by switching the changeover switch means.

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