阅读说明：本技术 车载电子控制装置 (Vehicle-mounted electronic control device ) 是由 西田充孝 于 2019-07-16 设计创作，主要内容包括：本发明得到为多个感性负载所共用、且低功耗地进行驱动电流的急速切断的廉价的车载电子控制装置。从与多个感性负载(104a、104b、104c)串联连接的各个开关元件(143a、143b、143c)的上游点起、经由放电二极管(144a、144b、144c)而连接的浪涌抑制电容器(150)通过负载电流的通断动作被初始充电至规定的限制电压V0为止,若由之后的通断动作而产生充电电压的增量电压ΔV,则放电晶体管(148)闭路,经由放电电阻(142)进行放电。(The invention provides an inexpensive in-vehicle electronic control device which is shared by a plurality of inductive loads and performs rapid disconnection of a drive current with low power consumption. A surge suppression capacitor (150) connected via discharge diodes (144a, 144b, 144c) from the upstream point of each of switching elements (143a, 143b, 143c) connected in series with a plurality of inductive loads (104a, 104b, 104c) is initially charged to a predetermined limit voltage V0 by the on-off operation of the load current, and when an incremental voltage DeltaV of the charging voltage is generated by the subsequent on-off operation, a discharge transistor (148) is closed and discharges via a discharge resistor (142).)

1. An in-vehicle electronic control device comprising:

switching elements connected in series to 1 or more inductive loads to which a battery voltage Vbb is supplied from an in-vehicle battery mounted on a vehicle; and a rapid cut-off circuit for suppressing a surge voltage generated when the switching element is opened and rapidly attenuating a drive current of the inductive load, wherein the in-vehicle electronic control device is characterized in that,

the rapid cutoff circuit includes:

the discharge diodes are respectively connected with 1 or more inductive loads; and a surge suppressing capacitor which is shared by the inductive load and suppresses an induced voltage generated by the inductive load to a predetermined limit voltage V0,

the surge suppressing capacitor is charged to an initial voltage that is obtained by an initial charging voltage obtained by turning on/off the inductive load by any one of the switching elements or obtained from a boost control circuit unit to obtain the predetermined limit voltage V0,

the rapid cutoff circuit further includes a discharge control circuit configured to discharge the charge of the surge suppression capacitor when a value of a charge voltage V of the surge suppression capacitor or a target voltage [ V-Vbb ] obtained by subtracting the battery voltage Vbb from the charge voltage V exceeds the limit voltage V0,

the discharge control circuit includes:

a voltage limiting diode that sets at least the limit voltage V0;

a discharge transistor that supplies a discharge current Ix to the discharge control circuit when the charging voltage V of the surge suppression capacitor exceeds the target voltage; and

a series resistance which is a discharge resistance for limiting the discharge current Ix to a value proportional to the target voltage or an equivalent discharge resistance which is configured by a constant current circuit for obtaining the discharge current Ix which is constant with respect to a variation of the target voltage,

when the vehicle-mounted battery is present in a charging path for initial charging or in a conducting path for the discharge current Ix, the charging voltage V becomes an added voltage [ V0+ Vbb ] of the limit voltage V0 and the battery voltage Vbb, and when the vehicle-mounted battery is not present in the charging path and the conducting path, the discharge current Ix is controlled so that the charging voltage V is equal to the limit voltage V0,

the lower limit of the individual on-off period T0i which is the on-off period of each of the switching elements is set,

so that each of the switching elements has a representative on-off period [ T0 ═ Σ Tfi × 2] or more, which is 2 times the total value of the individual off-times Tfi during which the individual off-current I0I flowing through the inductive load is attenuated to 0 while the switching element is open.

2. The in-vehicle electronic control device according to claim 1,

the surge suppressing capacitor includes a capacitance C for performing initial charging in which the charging voltage V is set to the predetermined limit voltage V0, which is a value 2 times or more the battery voltage Vbb, by turning on and off the representative load by the switching element or by sequentially turning on and off the plurality of switching elements,

the representative load is a dummy load in which 1-time individual discharge energy [ E0I ═ L0I × I0I calculated from the individual cutoff current I0I and the individual inductance L0I of the inductive load²/2]An individual discharge power [ P0i ═ E0i/T0i ] obtained by dividing the individual on-off period T0i]The total value Σ P0i of n and the representative discharge power [ P0 ═ E0/T0 ] of each of the n representative loads]Total discharge power [ P ═ n × P0, which is the total value of (a)]The phase of the two phases is equal to each other,

the breaking current of the representative load is representative breaking current I0, the inductance of the representative load is representative inductance L0, the on-off period of the representative load is representative on-off period T0,

the representative discharge energy E0 of 1 representative load is represented by the formula [ E0 ═ L0 × I0²/2]To indicate that the user is not in a normal position,

the number of initial charging times N for initial charging by the representative load up to the limit voltage V0 is represented by the formula [ N ═ (C/L0) × (V0/I0)²]To indicate that the user is not in a normal position,

a representative incremental voltage Δ V0 generated by performing 1-time energization interruption of the representative load after the initial charging is completed is expressed by the formula

3. The in-vehicle electronic control device according to claim 1,

the surge suppressing capacitor is connected to the boost control circuit section for initial charging at the start of driving of the vehicle,

the boost control circuit unit includes:

an inductive element connected to the on-vehicle battery;

a charging diode that charges the surge suppression capacitor with an induced voltage generated by the induction element in response to an on/off operation of the boosting switching element; and

a feedback control circuit for controlling a switching operation of the boosting switching element so that the charging voltage V of the surge suppression capacitor becomes equal to or lower than a voltage [ V0+ Vbb ] which is an addition voltage of the limit voltage V0 and the battery voltage Vbb,

the in-vehicle battery is connected in series with the path of the initial charging, or the in-vehicle battery exists in a current attenuation circuit of the inductive load when the switching element is opened.

4. The in-vehicle electronic control device according to claim 1,

the surge suppressing capacitor is connected to the boost control circuit section for initial charging at the start of driving of the vehicle,

the boost control circuit unit includes:

an inductive element connected to the on-vehicle battery;

a high-voltage capacitor that is charged to a high-voltage Vh equal to or higher than the limit voltage V0 via a charging diode by an induced voltage generated by the induction element in response to an on/off operation of the boosting switching element; and

a feedback control circuit that controls a switching operation of the boosting switching element so that a charging voltage of the high-voltage capacitor becomes equal to or lower than the high-voltage Vh for fuel injection of the vehicle,

the high-voltage capacitor is configured to perform rapid power supply to the fuel injection solenoid via the drive control circuit unit,

the on-vehicle electronic control device is provided with a voltage reduction circuit including an initial charging diode or an initial charging resistor for performing initial charging of the surge suppression capacitor,

the voltage reducing circuit is configured to reduce the initial charging voltage for the surge suppression capacitor to be equal to or less than an added voltage [ V0+ Vbb ] of the limit voltage V0 and the battery voltage Vbb.

5. The in-vehicle electronic control apparatus according to any one of claims 1 to 4,

one of the series circuits of the inductive load and the switching element is connected to the upstream side of the other,

the parallel circuit of the surge suppressing capacitor and the discharge control circuit is connected to the inductive load in parallel via the discharge diode and a common short-circuit preventing diode,

when any one of the switching elements is open-circuited, the surge suppression capacitor is connected in series with a 1 st preliminary charging resistor connected to the battery voltage Vbb from the in-vehicle battery via the inductive load and the discharge diode,

the 1 st pre-charge resistor is connected in series with the inductive load, and suppresses the pre-charge current for the surge suppressing capacitor to a current in a range where the inductive load does not malfunction,

the short-circuit prevention diode is configured to prevent both ends of the 1 st pre-charge resistor from being connected between positive and negative electrodes of the in-vehicle battery.

6. The in-vehicle electronic control apparatus according to any one of claims 1 to 4,

the inductive load is connected in series upstream of the switching element,

a positive side terminal of the surge suppressing capacitor is connected to a downstream side terminal of the inductive load via the discharge diode,

the negative side terminal of the surge suppressing capacitor is connected to a ground line GND connected to the negative terminal of the in-vehicle battery,

the discharge control circuit is connected in parallel with the surge suppression capacitor, or a negative-side terminal thereof is connected to a positive power supply line of the in-vehicle battery via a regenerative diode,

the surge suppressing capacitor is charged to the battery voltage Vbb by the in-vehicle battery via a reverse flow preventing diode and a 2 nd preliminary charging resistance,

the 2 nd auxiliary charging resistor is a current limiting resistor that suppresses a shunt current flowing into the surge suppressing capacitor via the inductive load and the discharge diode when the switching element is open,

the backflow prevention diode is configured to prevent charge of the surge suppression capacitor from leaking to the in-vehicle battery.

7. The on-vehicle electronic control device according to any one of claims 1 to 6,

the discharge control circuit is composed of a No. 1 discharge control circuit composed of a junction transistor or a field effect transistor,

the 1 st discharge control circuit includes:

a series circuit of the voltage limiting diode and a drive resistor connected in parallel with the surge suppressing capacitor;

the discharge transistor responsive to a voltage across the drive resistor; and

a series circuit of the discharge transistor and the discharge resistor connected in parallel with the surge suppressing capacitor,

the discharge transistor is composed of a junction transistor in which a base voltage Vbe between a base terminal and an emitter terminal becomes an operating voltage Vd, or a field effect transistor in which a gate voltage Vg between a gate terminal and a source terminal becomes the operating voltage Vd,

the junction transistor uses an NPN junction transistor in a case where the driving resistor is connected at a downstream position of the voltage limiting diode, uses a PNP junction transistor in a case where the driving resistor is connected at an upstream position of the voltage limiting diode,

an N-channel field effect transistor is used as the field effect transistor when the driving resistor is connected at a downstream position of the voltage limiting diode, and a P-channel field effect transistor is used as the field effect transistor when the driving resistor is connected at an upstream position of the voltage limiting diode,

the charging voltage V of the surge suppressing capacitor exceeds a limit voltage [ V0 ═ Vz + Vd ] which is an added value of the limit operating voltage Vz of the voltage limiting diode and the operating voltage Vd, the discharge transistor is driven in a closed circuit, and a discharge current [ Ix ═ V/Rx ] inversely proportional to a discharge resistance Rx which is a resistance value of the discharge resistance flows,

when the charging voltage V is less than the limit voltage [ V0 ═ Vz + Vd ], the discharge transistor is open-circuited.

8. The on-vehicle electronic control device according to any one of claims 1 to 6,

the discharge control circuit is composed of a No. 2 discharge control circuit composed of a junction transistor or a field effect transistor,

the 2 nd discharge control circuit includes:

a series circuit of the voltage limiting diode and a drive resistor connected in parallel with the surge suppressing capacitor;

a middle transistor responsive to a voltage across the drive resistor;

a series circuit of an intermediate drive resistor, an intermediate voltage limiting diode, and the intermediate transistor connected in parallel with the surge suppressing capacitor; and

a series circuit of the equivalent discharge resistance and the discharge transistor connected in parallel with the surge suppressing capacitor,

the discharge transistor is turned on in response to the value of the intermediate limiting voltage Ve of the intermediate voltage limiting diode,

the intermediate transistor is driven in a closed circuit state by the charging voltage V of the surge suppressing capacitor exceeding a limit voltage [ V0 ═ Vz + Vd ] which is an addition value of the limit operation voltage Vz of the voltage limiting diode and the drive voltage Vd of the intermediate transistor, and the intermediate voltage limiting diode is energized via the intermediate drive resistor,

the discharge transistor is configured to perform constant current discharge of the discharge current Ix based on [ Rx × Ix + Vd ═ Ve ] so that an added value [ Rx × Ix + Vd ] of a feedback voltage [ Rx × Ix ] that is a product of a discharge resistance Rx of the equivalent discharge resistance and the discharge current Ix flowing into the discharge resistance Rx and an operating voltage Vd of the discharge transistor is equal to the intermediate limit voltage Ve of the intermediate voltage limit diode.

9. The on-vehicle electronic control device according to any one of claims 1 to 6,

the discharge control circuit is composed of a No. 3 discharge control circuit composed of junction transistors or field effect transistors,

the 3 rd discharge control circuit includes:

a series circuit of the voltage limiting diode and a drive resistor connected in parallel with the surge suppressing capacitor;

a middle transistor responsive to a voltage across the drive resistor;

a series circuit of a pair of intermediate drive resistors connected in series and the intermediate transistor connected in parallel with the surge suppressing capacitor; and

a series circuit of the equivalent discharge resistance and the discharge transistor connected in parallel with the surge suppressing capacitor,

the discharge transistor is turned on in response to a divided voltage γ V of the charging voltage V generated by one of the pair of intermediate driving resistors,

the intermediate transistor is driven in a closed circuit state by the charging voltage V of the surge suppressing capacitor exceeding a limit voltage [ V0 ═ Vz + Vd ] which is an addition value of the limit operation voltage Vz of the voltage limiting diode and the driving voltage Vd of the intermediate transistor, and the divided voltage γ V is generated in one of the pair of intermediate driving resistors,

the discharge transistor is configured to perform variable current discharge of the discharge current Ix that varies according to a value of the charge voltage V based on an equation [ Rx × Ix + Vd ═ γ V ] such that an added value of a feedback voltage [ Rx × Ix ] that is a product of a discharge resistance Rx of the equivalent discharge resistance and the discharge current Ix flowing into the discharge resistance Rx and an operation voltage Vd of the discharge transistor is equal to the divided voltage γ V.

10. The in-vehicle electronic control apparatus according to claim 8 or 9,

the equivalent discharge resistor is connected to an emitter terminal side or a source terminal side of the discharge transistor, the heat generation dispersion resistor is connected in series to a collector terminal or a drain terminal side of the discharge transistor,

the dispersion resistance Re, which is a resistance value of the heat generation dispersion resistance, is set to be larger than the discharge resistance Rx, which is a resistance value of the equivalent discharge resistance.

Technical Field

The present invention relates to an in-vehicle electronic control device that quickly interrupts a drive current of an inductive electric load, and more particularly, to an in-vehicle electronic control device that is improved to stably control quick-interruption characteristics.

Background

As is well known, various types of surge voltage suppression circuits are used to suppress a surge voltage generated when a drive current of an inductive electric load such as a solenoid valve or an electromagnetic relay is cut off. Fig. 7A is a circuit diagram showing a part of a conventional in-vehicle electronic control device. In fig. 7A, a discharge diode 544a configured as a rectifier diode is connected in parallel with an inductive load 504a to which power is supplied from an on-vehicle battery 101 having a rated output voltage of, for example, DC12[ V ] via an output contact 102 of a power relay and a switching element 543a, and a drive current when the switching element 543a is closed is rectified and attenuated by opening the switching element 543 a.

The operating voltage of the inductive load including the solenoid valve and the electromagnetic relay is, for example, about DC 6V, and when the normal voltage DC 14V of the in-vehicle battery 101 is applied, the drive current is stabilized after a sudden increase, and the solenoid valve and the electromagnetic relay operate. However, there are problems as follows: when the deactivation recovery voltage at which the solenoid valve or the electromagnetic relay as the inductive load is restored to the deactivated state is, for example, DC3[ V ], the current attenuation after the switching element 543a is opened is slow, and therefore the deactivation recovery timing at which the solenoid valve or the electromagnetic relay is restored to the deactivated state greatly varies.

Fig. 7B is a circuit diagram showing a part of another conventional in-vehicle electronic control device. In fig. 7B, in the inductive load 504B to which power is supplied from the in-vehicle battery 101 having a rated output voltage of DC12[ V ], for example, via the output contact 102 of the power relay and the switching element 543B, the switching element 543B is connected in parallel with a voltage limiting diode 541 for limiting an operating voltage to [ Vz ═ DC50] [ V ], for example. In the conventional apparatus shown in fig. 7B, the switching element 543B connected in series with the inductive load 504B is opened, and thereby a current when the switching element 543B is closed flows into the voltage limiting diode 541 as the off current I0, and the off current I0 rapidly decays to "0" after the off time Tf.

As a result, although the inactivity recovery timing at which the solenoid valve or the electromagnetic relay as the inductive load is recovered to the inactive state when the switching element 543b is opened is stable, excessive power consumption whose maximum power consumption is [ I0 × Vz ] temporarily occurs in the voltage limiting diode 541, and the value of the maximum power consumption is a value obtained by multiplying the power consumption of the inductive load 504a by the limiting operation voltage [ Vz/battery voltage Vbb ].

In addition, according to the ratio of the off time Tf to the on-off period T0, as shown by the equation [ < I0/2> × Vz × Tf/T0], the average power consumption of the voltage limiting diode 541 is greatly reduced by the instantaneously generated maximum power consumption [ I0 × Vz ], but the instantaneously generated maximum power consumption [ I0 × Vz ] is excessively large, and therefore, it is necessary to use the voltage limiting diode 541 having a large capacity.

Further, patent document 1 discloses another conventional in-vehicle engine control device configured to: the fuel injection solenoid 103i in fig. 1 is rapidly excited from the high-voltage capacitor 114a charged to a boosted high voltage Vh1 of DC72[ V ], for example, by the boost control unit 110A via the rapid excitation switching element 122j, and then the battery voltage Vbb is applied via the power supply continuation switching element 121j, and when the rapid cutoff switching element 123i is opened shortly thereafter, the high-voltage capacitor 114a is regeneratively charged by the electromagnetic energy accumulated in the solenoid 103i via the recovery diode 160 i.

Therefore, the conventional vehicle-mounted engine control device disclosed in patent document 1 has the following features: however, in this conventional device, since the charging energy regenerated by the high-voltage capacitor 114a is smaller than the driving energy of the electromagnetic coil 103i required for the high-voltage capacitor 114a, the charging voltage of the high-voltage capacitor 114a cannot be made excessively large by the regenerative charging.

Disclosure of Invention

Problems to be solved by the invention

(1) Description of the problems of the prior art

As described above, according to the conventional apparatus shown in fig. 7A, the inductive load 504a is not cut off rapidly, and there is a problem as follows: the non-operation recovery timing of the solenoid valve or the electromagnetic relay as the inductive load is unstable. Further, according to the other conventional apparatus shown in fig. 7B, there are problems as follows: the instantaneous power consumption of the voltage limiting diode 541 is excessive, and a large-capacity voltage limiting diode 541 is required. In the case of the in-vehicle engine control device according to patent document 1, although the present invention is applied to a case where the charging energy for the high-voltage capacitor 114a can be reused, there are problems as follows: an overcharge preventing circuit for a high-voltage capacitor is required for an inductive load that does not require rapid excitation.

In addition to the above conventional devices, a snubber circuit including a series circuit of a surge voltage snubber capacitor and a current limiting resistor is connected in parallel to an inductive element or a switching element, but in this snubber circuit system, it is necessary to separately determine the capacitance of the capacitor and the current limiting resistor according to the characteristics of the inductive load, and there is at least the following problem: not shared by multiple inductive loads.

(2) Description of the objects of the present application

The present invention has been made to solve the above-described problems of the conventional devices, and an object of the present invention is to provide an in-vehicle electronic control device capable of suppressing instantaneous excessive power consumption generated in a rapid disconnection circuit and reducing a cost burden.

Technical solution for solving technical problem

The application discloses on-vehicle electronic control device includes:

switching elements connected in series to 1 or more inductive loads to which a battery voltage Vbb is supplied from an in-vehicle battery mounted on a vehicle; and a rapid cut-off circuit for suppressing a surge voltage generated when the switching element is opened and rapidly attenuating a drive current of the inductive load, wherein the in-vehicle electronic control device is characterized in that,

the rapid cutoff circuit includes:

the discharge diodes are respectively connected with 1 or more inductive loads; and a surge suppressing capacitor which is shared by the inductive load and suppresses an induced voltage generated by the inductive load to a predetermined limit voltage V0,

the surge suppressing capacitor is charged to an initial voltage that is obtained by an initial charging voltage obtained by turning on/off the inductive load by any one of the switching elements or obtained from a boost control circuit unit to obtain the predetermined limit voltage V0,

the rapid cutoff circuit further includes a discharge control circuit configured to discharge the charge of the surge suppression capacitor when a value of a charge voltage V of the surge suppression capacitor or a target voltage [ V-Vbb ] obtained by subtracting the battery voltage Vbb from the charge voltage V exceeds the limit voltage V0,

the discharge control circuit includes:

a voltage limiting diode that sets at least the limit voltage V0;

a discharge transistor that supplies a discharge current Ix to the discharge control circuit when the charging voltage V of the surge suppression capacitor exceeds the target voltage; and

a series resistance which is a discharge resistance for limiting the discharge current Ix to a value proportional to the target voltage or an equivalent discharge resistance which is configured by a constant current circuit for obtaining the discharge current Ix which is constant with respect to a variation of the target voltage,

when the vehicle-mounted battery is present in a charging path for the initial charging or in a conducting path for the discharge current Ix, the charging voltage V becomes an added voltage [ V0+ Vbb ] of the limit voltage V0 and the battery voltage Vbb, and when the vehicle-mounted battery is not present in the charging path and the conducting path, the discharge current Ix is controlled so that the charging voltage V is equal to the limit voltage V0,

the lower limit of the individual on-off period T0i which is the on-off period of each switching element,

so that each of the switching elements has a representative on-off period [ T0 ═ Σ Tfi × 2] or more, which is 2 times the total value of the individual off-times Tfi during which the individual off-current I0I flowing through the inductive load is attenuated to 0 while the switching element is open.

Effects of the invention

According to the on-vehicle electronic control device that this application discloses, it includes: a switching element connected in series to 1 or more inductive loads supplied with a battery voltage Vbb, respectively; and a rapid cut-off circuit for suppressing a surge voltage generated when the switching element is opened and rapidly attenuating a drive current of the inductive load,

the rapid cut-off circuit includes a common surge suppression capacitor connected to discharge diodes connected to 1 or more inductive loads, respectively, the charge voltage V of the surge suppression capacitor being initially charged to an initial voltage at which the predetermined limit voltage V0 is obtained,

the rapid cut-off circuit further includes a discharge control circuit for suppressing an overcharged state of the surge suppressing capacitor, the discharge control circuit including a voltage limiting diode for setting at least the limiting voltage V0, a discharge transistor for limiting a discharge current Ix flowing in the discharge control circuit, and a series resistor,

the on-off period T0i of the switching elements is limited to a lower limit so that each of the switching elements has a value [ T01 ≧ 2 × Σ Tfi ] which is 2 times or more the total value of the individual off times Tfi of the plurality of switching elements.

Therefore, the surge voltage is suppressed by the common surge suppressing capacitor and the discharge control circuit at the time of opening the circuit of each of the plurality of switching elements, and the rapid disconnection of the inductive load can be performed after the initial charging of the surge suppressing capacitor, the disconnection control characteristic of the inductive load is stable, and,

the individual interruption current I0I of the inductive load attenuates due to the short individual interruption time Tfi, whereas the individual discharge current Ixi is a substantially constant current, and the discharge is completed within a predetermined long period of the representative on-off period [ T0 ≧ 2 × Σ Tfi ], so that even if the discharge current [ Ix ≧ Σ Ixi ], which is the sum of the plurality of individual discharge currents Ixi, is used, the occurrence of an instantaneous excessive loss in the discharge control circuit that absorbs the surge voltage can be suppressed, and there is an effect that inexpensive circuit components can be used.

Further, when the surge suppressing capacitor and the discharge control circuit are used in common and applied to a plurality of inductive loads, the cost burden can be further reduced. In addition, when the initial charging of the surge suppression capacitor is performed by the on/off operation of the inductive load, the rapid cutoff function for the inductive load is gradually increased until the charging voltage V of the surge suppression capacitor reaches the limit voltage V0 or the sum of the limit voltage V0 and the battery voltage Vbb, but the discharge control circuit prohibits the generation of the discharge current Ix during the initial charging period, and the initial charging can be completed quickly.

Drawings

Fig. 1 is a block diagram showing the overall configuration of an in-vehicle electronic control device according to embodiment 1.

Fig. 2A is a circuit diagram showing a 1 st discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and shows a case where a junction transistor is used.

Fig. 2B is a circuit diagram illustrating a 2 nd discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and illustrates a case where a junction transistor is used.

Fig. 2C is a circuit diagram showing a 3 rd discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and is shown using a junction transistor.

Fig. 3A is a circuit diagram showing a modification of the 1 st discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and shows a case where a field effect transistor is used.

Fig. 3B is a circuit diagram showing a modification of the 2 nd discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and shows a case where a field-effect transistor is used.

Fig. 3C is a circuit diagram showing a modification of the 3 rd discharge control circuit in the in-vehicle electronic control devices according to embodiments 1 to 4, and shows a case where a field-effect transistor is used.

Fig. 4 is a block diagram showing the overall configuration of the in-vehicle electronic control device according to embodiment 2.

Fig. 5 is a block diagram showing the configuration of the in-vehicle electronic control device according to embodiment 3.

Fig. 6 is a block diagram showing the configuration of the in-vehicle electronic control device according to embodiment 4.

Fig. 7A is a circuit diagram showing a part of a conventional in-vehicle electronic control device.

Fig. 7B is a circuit diagram showing a part of another conventional in-vehicle electronic control device.

Fig. 7C is a circuit diagram of a part of the in-vehicle electronic control device for explaining the operation principle of the in-vehicle electronic control device according to the present application.

Detailed Description

First, an outline of the in-vehicle electronic control device according to the present application will be described. Fig. 7C is a circuit diagram of a part of the in-vehicle electronic control device for explaining the operation principle of the in-vehicle electronic control device according to the present application. In the following description, the inductive loads 504a, 504b, and 504c described later are sometimes described by the reference numeral i instead of the reference numerals a, b, and c and are also referred to as "504 i", the switching elements 543a, 543b, and 543c are sometimes described by the reference numeral i instead of the reference numerals a, b, and c and are also referred to as "543 i", and the discharge diodes 544a, 544b, and 544c are similarly described by the reference numeral i instead of the reference numerals a, b, and c and are also referred to as "544 i".

In fig. 7C, the switching element 543C supplies power from the on-vehicle battery 101 of, for example, the DC12[ V ] system to the inductive load 504C through the output contact 102 of the power relay. The switching element 543c is connected in parallel with the surge suppressing capacitor 150 via a discharge diode 544 c. The surge suppression capacitor 150 is connected in parallel with the discharge control circuit 160.

The discharge control circuit 160 includes: a discharge resistor 142 having one end connected to the positive electrode terminal of the surge suppression capacitor 150; a discharge transistor 148 having a collector connected to the other end of the discharge resistor 142 and an emitter grounded; a voltage limiting diode 141 having a cathode connected to one end of the discharge resistor 142 and an anode connected to the base of the discharge transistor 148 via a resistor; and a driving resistor 146 having one end connected to the anode of the voltage limiting diode 141 and the other end grounded.

When the charging voltage V of the surge suppression capacitor 150 exceeds the limit voltage [ V0 ═ Vz + Vd ], which is the sum of the limit operation voltage Vz of DC50[ V ] and the operation voltage Vd of the discharge transistor 148 set by the voltage limiting diode 141, for example, the discharge transistor 148 is closed via the drive resistor 146, and the discharge current [ Ix ═ V/Rx ] limited by the discharge resistor Rx of the discharge resistor 142 flows through the discharge resistor 142, which is the series resistance of the discharge transistor 148.

Further, the [ limit operating voltage Vz > operating voltage Vd ] and the limit voltage [ V0 ≈ Vz ] are obtained, and the discharge diode 544i always prevents the electric charge charged in the surge suppressing capacitor 150 from being reversely discharged through the inductive load 504c or the switching element 543 c.

Here, as shown in fig. 7B, in the case where the surge suppressing capacitor is not provided, the individual off current I0I when the switching element 543B is opened is caused to flow into the voltage limiting diode 541, and the individual off current I0I attenuates to 0 over the individual off time Tfi of a short time, however, at this time, the peak power generated in the voltage limiting diode 541 is [ Vz × I0I ≈ V0 × I0I ], and the individual discharge energy E0I is [ E0I ≈ Tfi × V0 × I0I/2 ]. However, the maximum value of the peak power generated in the voltage limiting diode 541 is determined by the product of the maximum off-current I0I and the limiting voltage V0, unless the driving currents of the plurality of inductive loads are simultaneously turned off.

On the other hand, in the case of fig. 7C, since the electromagnetic energy of the inductive load 504C when the switching element 543C is opened is accumulated in the surge suppressing capacitor 150 and the accumulated charge is discharged for a sufficiently longer time than the individual cut-off time Tfi of the inductive load 504C, that is, for a period of the individual on-off period T0I of the switching element 504C, the individual discharge current Ixi can be suppressed to a value of the arithmetic expression [ Ixi ═ 0.5 × I0I × Tfi/T0I ] obtained by multiplying the average value of the individual cut-off currents I0I (the intermediate value I0I/2 attenuated from I0I) by the value Tfi/T0I, and the peak power consumption generated in the discharge control circuit 160 can be greatly suppressed.

Further, since the power supply drive time Ton for the inductive load 504c is larger than the rapid cut-off time Tfi and the individual on/off period [ T0I ═ Ton + Tfi ≧ 2Tfi ] is set regardless of the open duration time Tff, by substituting [ Tfi/T0I ≦ 0.5] into the above-described operational expression [ Ixi ═ 0.5 × I0I × Tfi/T0I ], the individual discharge current Ixi corresponding to the individual cut-off current 10I is equal to or less than 1/4 of the individual cut-off current I0I, and the relationship of [ ∑ Ixi ≦ Σ I0I/4] is satisfied even in the respective sum values.

In addition, the individual on-off period T0i and the representative on-off period T0 are defined as in the following equation (1).

T0i is more than or equal to Tfi + ∑ Tfi > 2 × Tfi, T0 is more than or equal to 2 × Sigma Tfi is more than or equal to T0 i. formula (1)

Next, all the electromagnetic energy Σ Ei released when all the load currents of n inductive loads are cut off 1 time at the same time or sequentially is expressed by the following expression (2).

∑Ei＝∑L0i×I0i²/2＝n×L0×I0²2. type (2)

Wherein, L0 i: inductance of individual inductive loads 104i

I0I: cut-off current of individual inductive load 104i

L0: inductance representing inductive load

I0: interrupting current representative of inductive load

n: number of inductive loads

Then, if the surge suppressing capacitor 150 has a capacitance C in which the electromagnetic energy passing through the equation (2) only 1 time is not enough to reach the limit voltage V0, the following equation (3) is satisfied.

∑Ei＜C×V0²2. type (3)

The incremental voltage Δ V of the surge suppressing capacitor 150, which is generated when all the load currents of the n inductive loads are simultaneously or sequentially cut off 1 time after the surge suppressing capacitor 150 is initially charged to the limit voltage V0, is expressed by the following equation (4).

∑Ei＝C×[(V0+ΔV)²-V0²]2. formula (4)

Further, the following formula (5) is obtained from the above formulae (2) and (3).

On the other hand, the number of initial charging times N required to charge the charging voltage V of the surge suppression motor to the predetermined limit voltage V0 by turning on and off 1 representative load is calculated by the following equation (6).

L0×I0²×N/2＝C×V0²/2

∴N＝(C/L0)×(V0/I0)²The type (6)

The incremental voltage Δ V of the surge suppression capacitor when 1 representative load is turned on and off only 1 time after the completion of the initial charging is calculated by the following equation (7).

L0×I0²/2＝C×[(V0+ΔV)²-V0²]/2

∴L0/C＝(V0/I0)²[(1+ΔV/V0)²-1]The type (7)

The following formula (8) is obtained from the above formulae (6) and (7).

In formula (8), if [ N ═ 1], formula (5) is obtained, and if [ N ═ 5], formula [ Δ V/V0 ═ 0.095], and if [ N ═ 10], formula [ Δ V/V0 ═ 0.049] is obtained, and therefore, as an actual specification, [ N ≧ 10] may be set.

Next, when the number of loads to be simultaneously energized and shut off in the period representing the on/off period T0 among the plurality of inductive loads is represented by n, the total discharge power generated by the n representative inductive loads, that is, the total power consumption P generated in the discharge control circuit 160 is represented by the following expression (9).

P＝∑Ei/T0＝0.5×n×L0×I0²[ formula (9) ] with/T0 ═ E X V0 ·

When the formula (9) is modified, the following formula (10) is obtained.

Sigma Ixi/(I0 Xn) ═ 0.5 × [ L0 × 10/T0 ]/V0. cndot. formula (10)

Here, the value of L0 × I0/T0 is an induced voltage when a voltage corresponding to a current increase rate (I0/T0) is applied to the representative inductor L0, and the induced voltage does not exceed the battery voltage Vbb, and therefore the following expression (10a) is obtained.

Sigma Ixi/I0 < 0.5 × (Vbb/V0). times.n.times.formula (10a)

Therefore, if V0 ≧ 2Vbb is set in advance, then [ Σ Ixi/I0 < 1] is achieved even in the case of [ N ═ 4], and the total discharge current [ Σixi ═ Ix ] for the discharge control circuit 160 in fig. 7C is smaller than 1 representative off current I0 and smaller than 4 times the representative off current I0 for the voltage limiting diode 541 in fig. 7B that does not include the surge suppression capacitor 150. Further, if [ V0 ≧ 4Vbb ] is set as an actual specification, then [ Σ Ixi/I0 < 0.9] is achieved even when [ n ═ 6], and even if simultaneous cutoff at [ n ═ 6] or less, the total discharge current [ Σ Ixi ═ Ix ] is smaller than 1 representative cutoff current I0.