JPH02179223A - Energizing device for induced load of automobile - Google Patents

Abstract

PURPOSE: To minimize a loss voltage drop by using a switching passage of an arbitrary channel-type MOS field effect transistor for polarity protecting and coasting conducting means, and connecting it in a forward direction by a conducting reverse operation and in a reverse direction by a non-conducting normal operation. CONSTITUTION: An N-channel MOS field effect transistor(FET) 6 is for preventing polarity misconnection, and conducted when a gate 6c is positively biased to a source 6a and non-conducted in a case of erroneous polarity connection, so that a source 6a is at substantially the same potential as that of the gate 6c. An FET 8 is a coasting conducting means. With a suitable bias of a gate 8c, a very low resistance is generated between a source 8a and a drain 8b. From this, a cut-off impulse voltage of inductance of a load 2 is limited. In this manner, a loss voltage drop can be minimized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to an electronic control circuit having a signal output terminal and a signal output terminal, and an in-vehicle device that is connected in front of the electronic control circuit and has an incorrect polarity. The present invention relates to a device for energizing an inductive load of a motor vehicle, comprising protection means for preventing the application of pressure and at least one inertial energization means connected substantially in parallel to the inductive load.

[Conventional technology]

In order to complete the vehicle by the use of guard loading and catching devices, in particular induction - conventional electric - for the energization of the load.
There is an increasing need to replace polarized relays with solid state semiconductor switches, in particular semiconductor output stages.

However, the one-chip integration of the electronic control and regulation functions together with the large open power semiconductor output stage makes it extremely susceptible to damage due to operating voltages of incorrect polarity. This is because, for example, large currents can reach the interior of the control device or the semiconductor chip via the connecting conductors emerging from the output stage or the servo circuit.

On the other hand, the electronic control system of a car must be indestructible even if the 1S Hayabusa is connected with the wrong polarity. In particular, an accumulator connected to a vehicle's on-board equipment with the wrong polarity must not cause a polarity misconnection failure of the electronic control unit.

A number of strategies are already known in order to obtain greater strength against polarization & IfP of heavy components.

For example, it is known to provide an electronic control unit with a central polarity misconnection prevention relay and to allow this operating voltage to reach the output stage only when the operating voltage is applied with the correct polarity. be. This relay is
It operates in conjunction with one or more semiconductor diodes associated with its excitation winding. This known measure allows the energized switching contacts of the relay to be connected with very low resistance! It has the advantage that the loss voltage drop is very small. However, in corrosive atmospheres or highly variable climates, the reliability of the contacts decreases. Furthermore, mispolarity protection relays are expensive, require valuable installation space, and are often not capable of automatic installation. Low-resistance mispolarization contacts desirably reduce power losses due to voltage drops, but the
Due to excitation currents on the order of mA, power losses degrade the efficiency of such devices.

It is also known to use active anti-polarity diodes in supplying the operating voltage of devices or output stages. In modern integrated drive circuits used for motor vehicle control, this drive circuit is partly integrated on a chip together with internal protection diodes for the semiconductor output stage.

The last mentioned solution has the disadvantage that the voltage drop due to the loss of polarity prevention diodes is relatively large. With a limiting tS current of 5 A, as is customary in modern 11 solenoid valves of ordinary 1M class motor vehicles, in the closed state of the controlling semiconductor output stage, the main power losses no longer occur in its switching transistors; , occurs in the polarity misconnection prevention diode. i.e. 1.6 under the worst conditions
A voltage drop of up to V occurs across the anti-polarity diode, resulting in an anti-mispolation power loss of 8W. The electronic means for dissipating lost heat makes the equipment case more expensive than using conventional mispolarization prevention relays.

Automotive actuators with induction drive impedance and step motors are operated by pulsed direct current. Preparation and pulse-like switching on and off of the direct current is preferably carried out by means of the initially mentioned solid state semiconductor switches, in particular semiconductor output stages.

In order to protect this semiconductor output stage against inductive cut-off dynamic pressure peaks and to prevent excessive switching spikes from entering the onboard system, a conventional semiconductor diode is connected in parallel to the output of the control device that is closed by an inductive load. It is therefore known to route the inductive impulse sWL current resulting from interruption of the energizing current of the inductive load through this semiconductor diode, so that dangerously high voltages do not occur due to the dissipating magnetic field.

If more rapid current pulsing is performed in order to reduce the power consumption of the magnet winding, the inert energization means will be inert energized correspondingly frequently, i.e. at short time intervals. # As a result of the generation of the current, the current integral becomes considerably large. This current integral, like the voltage drop caused by the operating current across the polarity mismatch prevention diode, results in power loss from the forward voltage of freeloading when energized. In practical applications, this voltage drop is IV or higher. Car control ¥i! Since devices tend to have a large number of outputs that are protected by the free-flowing means, it is desirable that the heat losses occurring in the free-running means are likewise as low as possible.

[111i1 to be solved by the invention] Therefore, the present invention is directed to the problem that occurs in the polarity mix-up prevention means or the inertia energization means in which the control flow or cut-off joint flows, which directly affects the manufacturing price of the electronic control circuit device. An object of the present invention is to provide an inductive U# load energizing system for an automobile that minimizes the loss voltage drop. Furthermore, this device is suitable for readily replacing conventional polarity misconnection prevention means and inertia means, ie it can be easily integrated into control equipment of existing designs.

[Means for resolving issues]

In order to solve this problem, according to the invention, an arbitrary channel type MOS li
The open path or source-drain of I field effect transistors is used to connect these MOSNs.

So that a field effect transistor can operate in reverse operation with conduction in the forward direction and normal operation with non-conduction in the reverse direction,
The switching paths of the MOS field effect transistors are connected.

〔Effect of the invention〕

According to the present invention, the conventional semiconductor diode opening/closing path provided for preventing polarity misconnection or inert energization,
It is replaced by an opening/closing path of an S-blade MOS field effect transistor (hereinafter referred to as a power MOS transistor) operating in the opposite direction.

In this mode of operation in which energization is avoided, modern power MO
The S transistor has a very small conduction resistance of about 20 to 100 mΩ, and with the normal energizing current in a car, the voltage drop across this resistance is only 0.1 to 0.5 V, and therefore the loss is less than the square of the power. Does not occur.

The control signals necessary for reverse operation can be applied to the large number of power MOS transistors thus used in the control device, preferably using a central charge pump, without causing significant power losses. It is possible to prevent connection due to polarity mismatch at a low cost as in the conventional method.

[Conventional example]

FIG. 1 shows a typical circuit arrangement in an electronic control unit for energizing a load, in particular an actuator or actuator having an inductive component in its impedance, either by opening/closing or by means of pulses. The regular control circuit 1 receives control signals at its control terminals IC and ld, and its supply terminals 1a and 1b are connected to the positive operating voltage uv obtained from the on-board power supply voltage UBatt applied to the terminal IO and the ground 20. connected between. This electronic control circuit is used to apply an operating voltage Uv from time to time to the load 2 via the semiconductor switch 3.

As the semiconductor switch 3, for example, a source 38 as an electrode
, an N-channel power MOS having a drain 3b, a gate 3C, and a channel diode 3d acting parasitically)
A transistor is provided. If necessary, the gate 3C of the transistor 3 is shown here only symbolically and the structure of the t-child control circuit I! The charge pump 7C, to be understood as a four-part component, allows for example 2 to be controlled in a known manner by a Siemens integrated output stage module BTS412A. The module itself is protected against reverse polarity connections.

Regarding the electronic control circuit l with the load 2 and the switching transistor 3, a diode 4 is provided in a known manner in order to prevent the on-board *S voltage 'Ba t t from being connected to the terminals IO and 20 with incorrect polarity. There is. As is well known, the diode 5 also acts as an inertia diode, and the load 2
By extending the extinction of the current in the induced component over time, the cut-off voltage induced in the load 2 is separated.

〔Example〕

The same functionality is obtained with the device of the invention according to FIG.

This function is for t-blade MOS in conducting reverse direction operation.
) - takes advantage of the fact that the transistor's channel resistance is practically equal to the channel resistance during normal operation (internal parasitic diodes do not conduct current due to their small longitudinal resistance)
. For the known device according to FIG. 1, the switching paths of the corresponding diodes are replaced by the switching paths of N-channel power MOS transistors each receiving a voltage in the opposite direction with respect to the normal polarity.

Source 6a, drain 6b, gate 6c as electrodes
The power MOS transistor 6 having a parasitic channel diode 6d is replaced by a polarity misconnection prevention diode 4. The gate 6c is connected to a charge pump 7a that applies a bias voltage to it, and this bias voltage is applied to the source 6a and the drain 6 when the polarity of the on-vehicle power supply voltage UBatt applied to the terminals 10 and 20 is correct.
The size is such that low resistance conduction of the power MOS transistor 6 is achieved between the power MOS transistor 6 and the power MOS transistor 6. For example, onboard power supply voltage U
At the correct polarity of B t t the gate 6c of the transistor 6 is positively biased with respect to the source 6a □
Then, the open/close path between the source 6a and drain 6b of the transistor 6 is switched to a closed state.

If the vehicle g supply voltage UBatt is connected to the terminals IO and 20 with the wrong polarity, the source 6a of the transistor 6, for example by a controlled release of the action of the charge pump 7a,
For example, the potential of the gate 6c and the gate 6c are almost the same. In this case, therefore, the transistor 6 having the polarity for normal operation is made non-conducting, thereby acting as a polarity misconnection prevention device.

The charge pump 7a is an auxiliary circuit that has a similar function to a DC voltage transformer and is operated separately, and adds a predetermined potential to an arbitrary control signal level between the ground and the vehicle power supply voltage UBatt. This allows the gate 6c to have a higher (positive) voltage with respect to ground than the source 6a. Such an auxiliary circuit can be used to charge a charging capacitor by adding a summable potential periodically to the control signal by means of a transformer or by suitably controlled switching means.
The sum voltage can be generated as a voltage and held in a filter capacitor. Deactivation of such a charge pump circuit is possible, for example, by supplying this charge pump circuit in a conventional manner from terminal 10 by means of a symbolically indicated separate, known, anti-polarity diode 9a. Since the very high resistivity of the power MOS transistors allows an almost electrostatic control and the power consumption of such charge pump circuits is therefore in the mW range, the overall efficiency of the device is reduced almost exclusively by said power supply. do not. The voltage loss in the polarity misconnection prevention diode 9a for the load pump therefore results in negligible heat loss.

Assisted by charge pump 7a, transistor 6 replaces a conventional anti-polarity diode, but its heat generation is extremely low. Transistor 6 50■
Based on the reverse channel resistance of Ω and the loss voltage of IV that occurs in a conventional anti-polarity diode with respect to the switching current of IA, the loss 1a force that occurs in a transistor operated in reverse conduction according to the present invention is therefore: That's about 20 times less.

Similarly, a power MO is controlled by an electronic control circuit l and has a source 8a, a drain 8b and a gate 8c as electrodes, and a channel diode 8d acting parasitically.
S)-transistor 8 also replaces the inertial current-carrying diode 5 according to FIG. Gate 8c is also a suitable charge pump 7
It is possible to apply a voltage using b. Due to the appropriate biasing of the gate 8c, upon polarity reversal of the voltage of the load 2 after the opening of the transistor 3, a very low resistance will be created between the source 8a and the drain 8b, resulting in a cut-off s voltage at the inductance of the load 2. Restrictions are in place.

Similarly, the gate 3C of the power MOS transistor 3 is also biased with an auxiliary potential by the charge pump 7C, so that the voltage range of the wound voltage between the gate 3C and the source 3a is
It is kept in the optimum range for perfect opening/opening action. Such a charge pump can act as a component of a complex integrated electronic control circuit l, as indicated symbolically. If necessary, such a charge pump 7C biases both transistors 3 and 8 at different electrostatic potentials, making it possible to omit charge pump 7b. The dashed connection line indicates this case.

Both transistors 3 and 8 short-circuit the load 2 or
Alternatively, it is possible to form a controllable half-bridge connected to the operating voltage UV, ie, connected to the on-board voltage UBatt via the polarity misconnection prevention diode 6. Both transistors 3 and 8 are electronic sideboard circuits! are alternately push-pull controlled to prevent both transistors from conducting at the same time, but without significant dead time between alternate conduction phases of both transistors.

In practical use, the inductive load 2 is a proportional 11ilfi! which is pulsed at a frequency of, for example, 5 kHz or higher.
It's an i dialect. With such a rapidly pulsed power supply, the heat generation of the free-flowing diode 5 according to FIG. 1 is relatively large. The device according to the invention firstly makes it possible to significantly reduce this.

The device according to the invention produces a very desirable low-pass filtering effect on the movable valve element in proportional inertia valves due to the cut-off inducer, pressure of the excitation winding, which can be limited to a very small value, thereby suppressing vibrations due to pulse frequencies. suppress.

According to FIG. 3, several mutually independent and possibly different zero points 1211+12b, 12c for the individual auxiliary voltages of the MOS field effect transistors 3.6 and 8 are shown.
A common charge pump circuit 7 is provided for all three power MOS transistors if necessary. Similar to the charge pump circuit 7a, such a common charge pump circuit 7 is connected between the terminals 10 and 20 with a diode 9, for example, to prevent polarity misconnection, and is connected between the terminals 10 and 20 to prevent conduction of the transistors 3 and 8. The orderly bias voltage generation for the FF can be made such that it does not occur at all or is blocked with incorrect polarity.

FIG. 4 shows a variant of the device according to the invention. Here, there is no need for a charge pump to operate the power MOS transistor, which acts as a polarization prevention device. In order to generate a control bias voltage in a conductive reverse operation in a very simple manner, the earth conductor is disconnected here. The operating voltage of the conduction voltage applied to the terminal IO as a bias voltage reaches the gate 6c of the power MOS transistor 6 via the protective front resistor 13. This embodiment can be used advantageously, for example, when pulsing an inductive load for powering to ground. When using phase M1m power MOS) transistors with complementary characteristic curves, the source-drain switching path of such a transistor is inserted into the positive supply conductor, and its gate is connected to the earth connection terminal 20 through a suitable resistor. If direct connection is possible, this modification can also be applied to those in which the ground conductor is not interrupted.

[Brief explanation of the drawing]

Fig. 1 is a principle connection diagram of a known example of a pulse energizing device for an inductive load of an automobile having a polarity misconnection prevention diode as an inertia-1 diode to suppress the cut-off voltage peak, and Fig. 2 shows a polarity misconnection prevention diode. MO3 for power with reverse operation of prevention diodes and inert current carrying diodes
) - the principle connection diagram of a device according to the invention replaced by a transistor; FIG. 3 is a principle connection diagram of a device using a central charge pump for the bias voltage of several power MOS transistors; FIG. FIG. 3 is a basic connection diagram of an embodiment that does not require a load pump circuit; l...Electronic control circuit, 2...Inductive load, 6, 8...
-MOS turtle field effect transistor, 6a-6b, 8a-
8b...Opening/closing passage (source-drain).

Claims (1)

[Claims] 1. An electronic control circuit having a signal input terminal and a signal output terminal;
protective means connected before the electronic control circuit to prevent the application of an on-board power supply voltage of incorrect polarity; and at least one inertial current-carrying means connected substantially in parallel to the inductive load. and as an inertial energizing means,
MOS field effect transistor of arbitrary channel shape (6,
8) is used to enable these MOS field effect transistors (6, 8) to operate in reverse operation with conduction in the forward direction and non-conduction normal operation in the reverse direction. An inductive load energizing device for an automobile, characterized in that an opening/closing path (6a-6b, 8a-8b) of a MOS field effect transistor is connected to the energizing device. 2. The gate (6c) of the MOS field effect transistor (6) connected in front of the electronic control circuit (1) is connected to the charge pump (7a) between the on-vehicle power supply terminals (10, 20) of the energizing device. Device according to claim 1, characterized in that it is connected to. 3 If the on-board power supply voltage with the wrong polarity is connected to the on-board power supply terminal (10,
20), the charge pump (7a) transfers this MO to the gate (6c) of the MOS field effect transistor (6).
3. Device according to claim 2, characterized in that the charge pump (7a) provides misconnection protection so as to provide a potential that renders the S field effect transistor non-conducting. 4. Device according to claim 2, characterized in that the charge pump (7a) is constructed essentially monolithically as a component of the integrated electronic control circuit (1). 5 Gate (8c) of MOS field effect transistor (8) connected in parallel to inductive load (2) as inertial current supply means
2. Device according to claim 1, characterized in that the is at least indirectly connected to the electronic control circuit (1). 6 Gate (8c) of MOS field effect transistor (8)
) cooperates with the charge pump (7b) to generate the electronic control circuit (
6. Device according to claim 5, characterized in that it is connected to 1). 7 As a switch that applies an operating voltage to the inductive load, a MOS field effect transistor (3) connected in series and capable of conducting in the normal direction is provided in front of the inductive load, and this M
2. Device according to claim 1, characterized in that the gate (3c) of the OS field effect transistor is controllable by an electronic control circuit (1). 8. Device according to claims 5 and 7, characterized in that both MOS field effect transistors (3.8) are push-pull controllable by the electronic control circuit (1). 9 Both MOS field effect transistors (3.8) are
9. Device according to claim 8, characterized in that it is controllable with a variable mark-to-space ratio in an alternating and complementary manner so as not to be conductive at the same time. 10 Both charge pumps (7a, 7b) are identical and only one charge pump (7) can handle several different potentials (12
Device according to claims 2 and 6, characterized in that it is capable of generating a, 12b, 12c). 11 Make sure that the gate (6c) of the MOS field effect transistor (6) connected in front of the electronic control circuit (1) is connected to the other vehicle power supply terminal (10) via the protective resistor (13). A device according to claim 1, characterized in that: