Electronic control device and control method for electronic control device

Abstract

The present invention provides a highly reliable electronic control device in which a plurality of inductive loads are connected in parallel with each other, which does not require a separate circuit for detecting a reverse current, and which can prevent a reverse current when a GND wire breaks. The present invention is characterized by comprising: a first high side switch element that electrically connects a battery power source to a first external load; a first low side switch element that electrically connects a ground to the first external load; a second high side switch element that electrically connects the battery power source to a second external load; and a second low side switch element that is connected to a ground to which the first low side switch element is also connected, and that electrically connects a ground to the second external load, wherein during a period in which a target current to the first external load is greater than a predetermined threshold, synchronous rectification control is carried out for on / off controlling of the first high side switch element and the first low side switch element, and during a period in which a target current to the first external load is equal to or lower than the predetermined threshold, recirculation control is carried out for switching off the first low side switch element and for on / off controlling of the first high side switch element.

Description

[Technical field]

[0001] The present invention relates to a configuration of an electronic control device that drives and controls a load, and a control method thereof, and more particularly to a technique that is effective when applied to an on-vehicle electronic control device that requires high reliability. [Background technology]

[0002] A current control device for a solenoid valve used in an automatic transmission for a vehicle controls the current value flowing through the solenoid valve by adjusting the ON / OFF timing of the switch element that controls the current flow to the solenoid valve through duty control of a PWM signal.The current value flowing through the solenoid is also measured and fed back to the PWM signal so that it matches the target value, controlling the current.

[0003] In a typical vehicle automatic transmission, multiple solenoid valves are connected and their inductive loads are driven and controlled by a single controller, with common wiring on the vehicle side to reduce the number of connector terminals and vehicle harnesses and make them smaller.

[0004] Background art in this technical field includes, for example, technology such as Patent Document 1. Patent Document 1 discloses "a control device that measures the time of a reverse current generated when a ground line is disconnected and turns off a low-side switch element." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 241469 Summary of the Invention [Problem to be solved by the invention]

[0006] In a configuration as described above in which multiple inductive loads are connected to a single inductive load driving device and the vehicle side of the inductive load driving device is connected by a common wiring, if the ground line of the inductive load driving device is broken, a reverse current may be generated from one inductive load to another inductive load.

[0007] When such an inductive load driving device is used in, for example, an automatic transmission for a vehicle, a behavior accompanied by a gear shift shock may occur due to a reverse current.

[0008] In the above Patent Document 1, an HS / LS control time measurement circuit 20 is added to detect reverse current, but this raises issues such as reliability problems due to the increased number of parts, and is disadvantageous in terms of miniaturizing and reducing the cost of the device.

[0009] Therefore, an object of the present invention is to provide a highly reliable electronic control device and a control method thereof that can prevent reverse current in advance when a GND is broken, without requiring an additional circuit for detecting reverse current, in an electronic control device in which multiple inductive loads are connected in parallel. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides It is an inductive load a first high-side switch element that connects a battery power source to a first external load; and a first low-side switch element that connects the first external load to ground; It is an inductive loadthe first external load is connected to a common ground, and the second low-side switch element is connected to the common ground with the first low-side switch element, and is connected to the ground for the second external load; and during a period in which a target current to the first external load is greater than a predetermined threshold, a synchronous rectification control is performed to control the first high-side switch element and the first low-side switch element to be turned on and off, and during a period in which the target current to the first external load is equal to or less than the predetermined threshold, a reflux control is performed to turn the first low-side switch element off and to control the first high-side switch element to be turned on and off.

[0011] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: It is an inductive load A control method for an electronic control device in which a plurality of external loads are connected in parallel and a low-side switch element of a first load driving device and a low-side switch element of a second load driving device are connected to a common ground, the method comprising the steps of: during a period in which a target current to a first external load is greater than a predetermined threshold, performing synchronous rectification control for controlling ON / OFF of a high-side switch element and a low-side switch element of a first load driving device that drives the first external load; and during a period in which the target current to the first external load is equal to or less than the predetermined threshold, performing reflux control for turning OFF the low-side switch element of the first load driving device and controlling ON / OFF of the high-side switch element of the first load driving device. Effect of the Invention

[0012] According to the present invention, in an electronic control device in which multiple inductive loads are connected in parallel, it is possible to realize a highly reliable electronic control device and a control method thereof that can prevent reverse current in advance when a GND is disconnected without requiring an additional circuit for reverse current detection.

[0013] This makes it possible to prevent unintended operation of the inductive load even when the GND is disconnected, and allows current control of the inductive load to continue.

[0014] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0015] [Figure 1] 1 is a functional block diagram of a current control device according to a first embodiment of the present invention. [Diagram 2] 2 is a timing chart showing the circuit operation of the current control device of FIG. 1. [Diagram 3] FIG. 6 is a functional block diagram of a current control device according to a second embodiment of the present invention. [Figure 4] 4 is a timing chart showing the circuit operation of the current control device of FIG. 3. [Diagram 5] FIG. 11 is a functional block diagram of a current control device according to a third embodiment of the present invention. [Figure 6] 6 is a timing chart showing the circuit operation of the current control device of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are designated by the same reference numerals, and detailed description of overlapping parts will be omitted.

[0017] In addition, the following description will be given using an example of a current control device for a vehicle automatic transmission in which multiple solenoid valves are connected and driven and controlled by a single CPU (Central Processing Unit). However, the present invention is not limited to this and can also be applied to current control devices for other purposes (also called electronic control devices (ECU: Electric Control Unit)). EXAMPLES

[0018] A current control device and a control method thereof according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a functional block diagram of a current control device 9 of the present embodiment. Fig. 2 is a timing chart showing the circuit operation of the current control device 9 of Fig. 1.

[0019] As shown in Fig. 1, the current control device 9 of this embodiment mainly comprises a CPU 14 and load drivers 1a and 1b that supply current to a plurality of solenoid valves 10a and 10b, which are external loads. Here, for the sake of simplicity, the number of solenoid valves and load drivers is reduced to two, but there is no limit to the number.

[0020] In both load driving devices 1a and 1b, one end of solenoid valves 10a and 10b that supply current is connected to a connection point between a high-side switch element 4 and a low-side switch element 5 that are connected in series to a battery power source 13. The other end of the solenoid valves 10a and 10b is connected to a common solenoid valve ground 11.

[0021] The CPU 14 calculates the current value to be supplied to the solenoid valves 10a, 10b required for the vehicle automatic transmission system, and outputs PWM signals 2a, 2b for synchronous rectification control that controls the ON / OFF of the high-side switch element 4 and the low-side switch element 5 to the load drivers 1a, 1b with the calculated current value as a target current.

[0022] Since the configuration and operation of the load driving devices 1a and 1b are basically the same, the configuration and operation of the load driving device 1b that drives the solenoid valve 10b will be mainly described below.

[0023] The load driver 1b, which has received the PWM signal 2b from the CPU 14, performs synchronous rectification control by using a switch control circuit 3b to turn on the high-side switch element 4 and turn off the low-side switch element 5 when the PWM signal 2b is at a high level, and supplies current from a battery power source 13 to a solenoid valve 10b via the high-side switch element 4.

[0024] On the other hand, when the PWM signal 2b is at a low level, synchronous rectification control is performed in which the high-side switch element 4 is turned OFF and the low-side switch element 5 is turned ON, cutting off the current supply from the battery power source 13 and releasing the energy stored in the solenoid valve 10b by circulating the current from the current control device ground 12 to the solenoid valve 10b via the low-side switch element 5.

[0025] The current flowing to the solenoid valve 10b can be increased or decreased by changing the duty ratio of the PWM signal 2b, and the duty ratio of the PWM signal 2b is feedback controlled to correct the difference between the target current from the CPU 14 and the current value flowing through the solenoid valve 10b, thereby realizing current control to the solenoid valve 10b.

[0026] The value of the current flowing through the solenoid valve 10b is detected by an HS current measurement circuit 6 and an LS current measurement circuit 7, which are connected to the high-side switch element 4 and the low-side switch element 5, respectively. Effectively, based on the current detection results, a current calculation circuit 8 calculates an average current value for a certain period required for feedback control, and transfers it to the CPU 14.

[0027] When a current flows through the first high-side switch element 4 in the load driver 1a, a current (reverse current) also flows into the solenoid valve 10b. The difference between the magnitude of this reverse current and the current flowing through the solenoid valve 10b via the second high-side switch element 4 in the load driver 1b becomes the current value that drives the solenoid valve 10b.

[0028] This current becomes a reverse current flowing toward the current driver 9 in the solenoid valve 10b when the second low-side switch element 5 is ON and when the value of the current supplied to the solenoid valve 10b is small.

[0029] Under normal circumstances, the reverse current is cancelled out by the current flowing to the solenoid valve 10b via the second high-side switch 4 or the return current flowing via the second low-side switch element 5, but for example, when the current control device ground 12, which is the common ground for the load driving device 1a and the load driving device 1b, is disconnected, the return current flowing from the current control device ground 12 via the second low-side switch element 5 disappears, and a reverse current flows from the solenoid valve 10b to the second low-side switch element 5 when the second low-side switch element 5 is ON. Therefore, depending on the value of the current flowing, the solenoid valve 10b may operate as a valve, which may cause an unintended gear shift shock.

[0030] 2, in the present embodiment, during normal control, the high-side switch element and the low-side switch element perform synchronous rectification control in accordance with the PWM signal during a period in which the target current for driving each solenoid valve 10a, 10b is equal to or greater than a predetermined threshold, and during a period in which the target current is equal to or less than the predetermined threshold, the low-side switch element is turned off by the switch control circuit 3b regardless of the PWM signal. At this time, the reflux current flows to the solenoid valve 10b via the parasitic diode of the low-side switch element.

[0031] A reverse current occurs when the current supplied to the solenoid valve 10b is small, so that the return current when the low-side switch element is OFF is also small, and heat generation by the low-side switch element 5 can be suppressed to a low level.

[0032] As described above, the current control device 9 (electronic control device) of this embodiment includes the first high-side switch element 4 that connects the battery power supply 13 to the first external load (solenoid valve 10a), the first low-side switch element 5 that connects the first external load (solenoid valve 10a) to the ground, the second high-side switch element 4 that connects the battery power supply 13 to the second external load (solenoid valve 10b), and the second high-side switch element 4 that is connected to a ground (current control device ground 12) common to the first low-side switch element 5 and connects the second external load (solenoid valve 10b) to the ground. and a second low-side switch element 4 that connects the first external load (solenoid valve 10b) to ground. During a period in which a target current to the first external load (solenoid valve 10a) is greater than a predetermined threshold, synchronous rectification control is performed to control the first high-side switch element 4 and the first low-side switch element 5 to be turned on and off, and during a period in which the target current to the first external load (solenoid valve 10a) is equal to or less than the predetermined threshold, reflux control is performed to turn the first low-side switch element 5 off and control the first high-side switch element 4 to be turned on and off.

[0033] By switching between synchronous rectification control and reflux control based on the threshold value at which backflow occurs when the common GND is broken, heat generation in the element is suppressed by synchronous rectification control when the command current (target current) is large, and by using control that can suppress backflow in the event of a break, it is possible to realize failover (F / O: fail-over) using a parasitic diode.

[0034] As a result, it is possible to reduce the harness (reducing the vehicle weight) by using a common GND at low cost and in a compact size.

[0035] Furthermore, in the current control device 9 (electronic control device) of this embodiment, when the target current to the first external load (solenoid valve 10a) is equal to or lower than a predetermined threshold, the first high-side switch element 4 and the first low-side switch element 5 are turned OFF.

[0036] When the command current (target current) is equal to or lower than a predetermined threshold, the return path is eliminated and reverse current can be prevented, preventing unintended operation of the solenoid valve and ensuring the safety of the vehicle system.

[0037] According to the current control device 9 (electronic control device) of this embodiment, even when the electronic control device ground 12, which is the common ground of the load driving device 1a and the load driving device 1b, is broken, the path of the reverse current is cut off, and unintended valve operation of the solenoid valve is prevented, while feedback control can be continued for solenoid valves that are capable of normal feedback control.

[0038] It goes without saying that the same effect can be obtained by turning off the low-side switch element 5 when the target value of the current supplied to the solenoid valve is 0, that is, by setting the predetermined threshold to 0 mA.

[0039] In addition, by setting the current to 0 mA, it is possible to eliminate the reflux current flowing to the parasitic diode of the low-side switch element and suppress heat generation in the low-side switch element. EXAMPLES

[0040] A current control device and a control method thereof according to a second embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a functional block diagram of a current control device 9 of the present embodiment. Fig. 4 is a timing chart showing the circuit operation of the current control device 9 of Fig. 3.

[0041] The configuration in FIG. 3 is basically the same as the configuration in FIG. 1, but is characterized in that the multiple solenoid valves 15a, 15b connected thereto do not operate at low current, and the predetermined threshold in the first embodiment is set to a current value at which the solenoid valves 15a, 15b do not operate.

[0042] In this embodiment, as shown in FIG. 4, during normal control, in a period in which the target current for driving each of the solenoid valves 15a, 15b is equal to or greater than the predetermined threshold, the high-side switch element and the low-side switch element perform synchronous rectification control in accordance with the PWM signal, and in a period in which the target current is equal to or less than the predetermined threshold, the low-side switch element is turned off by the switch control circuit 3b regardless of the PWM signal.

[0043] As a result, even when the electronic control device ground 12, which is the common ground for the load driving device 1a and the load driving device 1b, is broken, the path of the reverse current is cut off, preventing unintended valve operation of the solenoid valve, while allowing feedback control to continue for solenoid valves that are capable of normal feedback control. EXAMPLES

[0044] A current control device and a control method thereof according to a third embodiment of the present invention will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a functional block diagram of a current control device 9 of the present embodiment. Fig. 6 is a timing chart showing the circuit operation of the current control device 9 of Fig. 5.

[0045] The solenoid valves controlled by the current control device (electronic control device) for controlling the vehicle's automatic transmission include a solenoid valve that controls the opening and closing of a lock-up clutch. The lock-up clutch is a mechanism that mechanically fixes the engine and the vehicle's automatic transmission and directly transmits engine torque, and the CPU configured in the current control device receives sensor signals from various sensors such as the vehicle's throttle sensor and vehicle speed sensor, and controls the opening and closing of the lock-up clutch according to the vehicle's condition.

[0046] If the lock-up clutch is unintentionally engaged, it can have an impact on the vehicle, such as causing the engine to stall. Therefore, a control is required to cut off the reverse current when the common ground of the current control device is broken, and to suppress unintentional operation of the lock-up clutch solenoid valve.

[0047] Therefore, in this embodiment, as shown in FIG. 5, to the configuration of embodiment 1 (FIG. 1), vehicle sensor signals 16 which are input conditions for engaging the lock-up clutch from various sensors such as a vehicle throttle sensor and a vehicle speed sensor are added, and information on the vehicle sensor signal 16 is input by the CPU 14 to the switch control circuit 3b and used for ON / OFF switch control of the high side switch element 4 and the low side switch element 5, thereby controlling the lock-up solenoid valve 17.

[0048] In this embodiment, as shown in FIG. 6, when the vehicle sensor signal condition requires lock-up engagement, the PWM signal 2b sent from the CPU 14 to the load driver 1b is transmitted to the switch control circuit 3b as a signal for turning on and off the high-side switch element 4 and the low-side switch element 5 to perform synchronous rectification control.

[0049] On the other hand, when the vehicle sensor signal condition requires disengagement of the lockup clutch, the PWM signal 2b sent from the CPU 14 to the load driver 1b is sent to the switch control circuit 3b as a signal to turn off both the high-side switch element and the low-side switch element.

[0050] Thus, according to this embodiment, by turning off low-side switch element 5 during the period when engagement of the lockup clutch is not necessary, i.e., the period when current is not supplied to lockup solenoid valve 17, when current control device ground 12, which is the common ground of current control device 9, is broken, the path of the reverse current is cut off and engagement of the lockup clutch at an unintended timing can be suppressed, making it possible to suppress the occurrence of abnormal vehicle conditions due to engine stalls, etc.

[0051] As described above, in the current control device 9 (electronic control device) of this embodiment, during low vehicle speed control without lock-up control, the first high-side switch element 4 and the first low-side switch element 5 are turned off. The vehicle speed without lock-up control is, for example, 0 km / h.

[0052] During low-speed vehicle control without lock-up control, the return path is eliminated, making it possible to suppress reverse current, preventing unintended operation of the solenoid valve and ensuring the safety of the vehicle system.

[0053] The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0054] In addition, the control lines and signal lines shown are those that are considered necessary for the explanation, and not all of the control lines and signal lines on the product are necessarily shown. [Explanation of symbols]

[0055] 1a, 1b... Load driving device, 2a, 2b... PWM signal, 3a, 3b... Switch control circuit, 4... High side switch element, 5... Low side switch element, 6... HS current measurement circuit, 7... LS current measurement circuit, 8... Current calculation circuit, 9... Current control device, 10a, 10b... Solenoid valve, 11... Solenoid valve ground (GND), 12... Current control device ground (GND), 13... Battery power source, 14... CPU, 15a, 15b... Solenoid valve that does not operate at low current, 16... Vehicle sensor signal, 17... Lock-up solenoid valve

Claims

1. A first high-side switch element that conducts a battery power source to a first external load that is an inductive load; a first low-side switch element that connects the first external load to a ground; a second high-side switch element that conducts the battery power to a second external load, which is an inductive load; a second low-side switch element connected to a common ground with the first low-side switch element and electrically connecting the second external load to ground; performing synchronous rectification control for controlling ON / OFF of the first high-side switch element and the first low-side switch element during a period in which a target current to the first external load is greater than a predetermined threshold; an electronic control device that performs reflux control by turning off the first low-side switch element and controlling the first high-side switch element to be ON and OFF during a period in which a target current to the first external load is equal to or less than the predetermined threshold value;

2. 2. The electronic control device according to claim 1, The electronic control device wherein the target current is 0A.

3. 2. The electronic control device according to claim 1, the first external load and the second external load are solenoid valves; The predetermined threshold is a current value at which a solenoid valve does not operate.

4. 2. The electronic control device according to claim 1, The electronic control unit is an in-vehicle electronic control unit, The electronic control device turns off the first high-side switch element and the first low-side switch element during low vehicle speed control without lock-up control.

5. 5. The electronic control device according to claim 4, An electronic control device in which the vehicle speed at which lockup control is not performed is 0 km / h.

6. A control method for an electronic control device in which a plurality of external loads, which are inductive loads, are connected in parallel, and a low-side switch element of a first load driving device and a low-side switch element of a second load driving device are connected to a common ground, comprising: performing synchronous rectification control for controlling ON / OFF of a high-side switch element and a low-side switch element of a first load driving device that drives the first external load during a period in which a target current to a first external load is greater than a predetermined threshold value; A control method for an electronic control device that performs reflux control by turning off a low-side switch element of the first load driving device and controlling the high-side switch element of the first load driving device to be ON and OFF during a period when a target current to the first external load is below the predetermined threshold.

7. A control method for an electronic control device according to claim 6, comprising the steps of: The control method for an electronic control device, wherein the target current is 0A.

8. A control method for an electronic control device according to claim 6, comprising the steps of: the plurality of external loads are solenoid valves; The control method for an electronic control device, wherein the predetermined threshold value is a current value at which a solenoid valve does not operate.

9. A control method for an electronic control device according to claim 6, comprising the steps of: The electronic control unit is an in-vehicle electronic control unit, A control method for an electronic control device, the method including turning off a high-side switch element and a low-side switch element of the first load drive device during low vehicle speed control without lock-up control.

10. A control method for an electronic control device according to claim 9, comprising the steps of: A control method for an electronic control device in which a vehicle speed at which lockup control is not performed is 0 km / h.

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