JP2008189026A - Power source switching device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source switching device for a vehicle simple in constitution capable of driving a switch means for switching power supply to an electric component required for maintaining the traveling of a vehicle by a double system during traveling. <P>SOLUTION: This power source switching device 10 for a vehicle comprises a microcomputer 12, a relay driving circuit 13, a relay driving circuit 14, and a F-V conversion circuit 15. Vehicle speed pulses 17 outputted from a vehicle speed sensor 16 are inputted to the F-V conversion circuit 15 via a signal input terminal 24. The F-V conversion circuit 15 outputs driving signals to the relay driving circuit 14 while the vehicle speed pulses 17 are inputted so as to actuate an IG relay 11 and maintain it in an actuated state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle power supply switching device that switches power supply from a battery to electrical components necessary for maintaining traveling of a vehicle such as an automobile.

  In the conventional vehicle power supply switching device, regarding the driving of the IG relay that switches the power supply from the battery to the electrical components necessary for maintaining the running of the vehicle, “The IG relay does not turn off while driving (non-operating state) The reliability is improved by adopting the “not to be)” configuration. That is, during traveling, even if one relay drive circuit fails, the IG relay is operated by the double relay drive circuit so that the other relay drive circuit operates the IG relay. .

  Examples of such a vehicle power supply switching device include those described in Patent Literature 1 and Patent Literature 2.

  In the prior art described in Patent Document 1, a latch circuit is provided in order to prevent the IG relay from turning off due to a malfunction of the microcomputer during traveling. Once the relay is actuated, this latch circuit maintains the operating state of the relay by maintaining the operating state of the FET in the driver circuit unless the start / stop switch is pressed in the non-running state of the vehicle.

  Further, in Patent Document 2, in an electronic control device that controls power supply to each part of a vehicle, when configuring a fail-safe circuit that cuts off power supply to each part of the vehicle when a microcomputer malfunctions, the following conditions must be satisfied: It is described that there is. That is, in order to avoid being out of control during traveling, the power supply should not be cut off during traveling. When the microcomputer of the power supply ECU is operating normally, the power is supplied regardless of the traveling state of the vehicle. Is not to be blocked. In addition, it is conceivable to use a vehicle speed pulse to determine whether or not the vehicle is running, and to use the above-described periodic pulse to determine whether or not the microcomputer is operating normally. It is described that the configuration may be such that the fail-safe circuit does not operate if it is input on one side.

And the fail safe circuit described in this patent document 2 instruct | indicates the power supply start to each part of a vehicle according to the operation state of the vehicle speed detection part which generates a vehicle speed pulse, and an ignition switch (or start / stop switch). According to the microcomputer that outputs a start command and periodically outputs a pulse signal (periodic pulse) during normal operation and the input state of the vehicle speed pulse and the periodic pulse, it becomes an active level when both inputs are interrupted. When a signal generation circuit that generates a state signal and a start command from a microcomputer are input, a relay provided in a power supply path is turned on, and an IG hold circuit that holds the state and a signal generation circuit generate When the status signal becomes active level, the status held by the IG hold circuit is canceled and Over consists of the IG cancellation circuit to turn off state.
JP-A-2005-48591 JP 2005-65114 A

    By the way, in the prior art described in the above-mentioned Patent Document 1, a latch circuit is provided to prevent the microcomputer from malfunctioning and turning off the IG relay during traveling, resulting in an increase in the number of parts. There was a problem. Further, in the conventional technique described in Patent Document 2, an IG hold circuit that holds the IG relay in an on state is provided in order to prevent the IG relay from being turned off during traveling. There was a problem of becoming.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to drive a switching unit that switches power supply to electrical components necessary for maintaining traveling of the vehicle in a double system while traveling. An object of the present invention is to provide a vehicular power supply switching device that can simplify the circuit and improve the reliability.

  In order to solve the above-described problem, the vehicle power source switching device according to the first aspect of the present invention includes a switching unit that switches power supply from a battery to an electrical component necessary for maintaining traveling of the vehicle. A vehicle power supply switching device for switching between operating states, the first power supply switching means and the second power supply switching means for operating the switching means, respectively, and the control means for controlling the first power supply switch means And an F / V conversion circuit to which a vehicle speed pulse is input, and the F / V conversion circuit outputs a drive signal to the second power source switching means while the vehicle speed pulse is being input. The switching means is operated.

  According to this aspect, the first power supply switching unit is controlled by the control unit, and the second power supply switching unit is output from the F / V conversion circuit while the vehicle speed pulse is input to the F / V conversion circuit. The switching means is actuated by the drive signal. Thus, the second power supply switching means is driven by the F / V conversion circuit while the vehicle speed pulse is input to the F / V conversion circuit, that is, while the vehicle is running, and keeps the switching means in the operating state. To do. Thereby, when vehicle speed exists, switching means, such as an IG relay, can be driven by a double system.

  In addition, a vehicular power source switching device capable of driving the switching unit in a double system can be realized with a simple configuration in which the second power source switching unit is controlled by an F / V conversion circuit to which a vehicle speed pulse is input. Further, the vehicle speed pulse is input to the F / V conversion circuit without passing through the control means, and while the vehicle speed pulse is being input to the F / V conversion circuit, the vehicle speed pulse is driven by the F / V conversion circuit to bring the switching means into the operating state. Thus, even if the control means (microcomputer) fails, the switching means can be kept in the operating state. Thereby, reliability is improved.

  Therefore, the switching means for switching the power supply to the electrical components necessary for maintaining the vehicle can be driven in a double system while traveling, and the circuit can be simplified and the reliability can be improved.

  According to the present invention, the switching means for switching the power supply to the electrical components necessary for maintaining the traveling of the vehicle can be driven in a double system while traveling, thereby simplifying the circuit and improving the reliability. A vehicular power supply switching device that can perform the operation can be obtained.

  Next, an embodiment embodying the present invention will be described with reference to the drawings.

  A vehicle power supply switching device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a vehicle power supply switching device according to an embodiment. FIG. 2 shows a detailed circuit configuration of the F / V conversion circuit and two relay drive circuits shown in FIG. FIG. 3 is a timing chart showing the operation of the vehicle power supply switching device.

  A vehicle power supply switching device 10 shown in FIG. 1 switches an IG relay 11 as a switching means for switching power supply from a battery to an electrical component necessary for maintaining traveling of the vehicle between an operating state and a non-operating state. It is embodied as a power supply switching ECU. Here, when the IG relay 11 is activated, the power (power supply voltage VB) from the battery is supplied to the electrical components necessary for maintaining the vehicle running. Further, when the IG relay 11 is deactivated, the supply of electric power (power supply voltage VB) from the battery to the electrical components necessary for maintaining the running of the vehicle is interrupted.

  The vehicle power supply switching device (hereinafter referred to as “power supply switching device”) 10 includes a microcomputer 12 as control means and a relay drive circuit (relay drive circuit A) 13 as first power supply switching means. And a relay drive circuit (relay drive circuit B) 14 as a second power supply switching means, and an F / V conversion circuit (frequency / voltage converter) 15. Further, the power supply switching device 10 includes an input interface (not shown) and an output interface.

  The power switching device 10 is characterized in that a vehicle speed pulse 17 output from the vehicle speed sensor 16 is input to the F / V conversion circuit 15, and the vehicle speed pulse 17 is input to the F / V conversion circuit 15. During the operation, the drive signal is output to the relay drive circuit 14 to operate the IG relay 11 and maintain the operation state. That is, the relay drive circuit 13 is controlled by the microcomputer 12 and the relay drive circuit 14 outputs a drive signal output from the F / V conversion circuit 15 while the vehicle speed pulse 17 is input to the F / V conversion circuit 15. Thus, the IG relay 11 is operated.

  The microcomputer 12 includes a CPU, a memory device (ROM, RAM), an input port, and an output port that are not shown.

  The relay drive circuit 13 includes a resistor R1 having one end connected to the output terminal of the microcomputer 12, an npn transistor T1 having a base connected to the other end of the resistor R1, and an emitter grounded, and a base of the transistor T1. A resistor R2 connected between the emitters; Further, the relay drive circuit 13 has a resistor R3 having one end connected to the collector of the transistor T1, a base connected to the other end of the resistor R3, and the collector supplying power from the battery (power supply voltage VB) to the IG relay 11. A pnp transistor T2 connected to the power supply line 20 to be supplied and a resistor R4 connected between the emitter and base of the transistor T2 are provided. The emitter of the transistor T2 is connected to a power supply line 23 to which power (power supply voltage VB) from the battery is supplied via the power input terminal 22.

  In the relay drive circuit 13, when a drive signal (H level on signal) is output from the microcomputer 12, the transistor T1 is turned on, the transistor T2 is also turned on, and the power from the battery (power supply voltage VB) is supplied as power. The power is supplied to the IG relay 11 via the lines 23 and 20 and the power output terminal 21 of the power switching device 10. Thereby, IG relay 11 will be in an operation state, and the electric power (power supply voltage VB) from a battery will be supplied to the electrical components required for driving maintenance of vehicles.

  On the other hand, when the L level off signal is output from the microcomputer 12, the transistors T1 and T2 are both turned off, and the supply of power (power supply voltage VB) from the battery to the IG relay 11 is interrupted. As a result, the IG relay 11 is deactivated, and the supply of power (power supply voltage VB) from the battery to the electrical components necessary for maintaining the running of the vehicle is interrupted.

  The F / V conversion circuit 15 has one end connected to the signal input terminal 24 of the power supply switching device 10 to which the vehicle speed pulse 17 from the vehicle speed sensor 16 is input, and one end connected to the other end of the resistor R5. A capacitor C1, a diode D1 having an anode side terminal connected to the other end of the capacitor C1, and a capacitor C2 having one end connected to the cathode side terminal of the diode D1 and the other end grounded. The F / V conversion circuit 15 having such a configuration converts the input vehicle speed pulse 17 into a DC voltage proportional to the frequency, and while the vehicle speed pulse 17 is being input, the drive signal ( H level ON signal) is output. On the other hand, when the vehicle is stopped and the vehicle speed pulse 17 is not input, an L level off signal is output to the relay drive circuit 14.

  The relay drive circuit 14 includes a resistor R10 having one end connected to the output terminal of the F / V conversion circuit 15, and an npn transistor T10 having a base connected to the other end of the resistor R10 and an emitter grounded. And a resistor R20 connected between the base and emitter of the transistor T10. Further, the relay drive circuit 14 includes a resistor R30 having one end connected to the collector of the transistor T10, a pnp transistor T20 having a base connected to the other end of the resistor R30, and a collector connected to the power line 20. And a resistor R40 connected between the emitter and base of the transistor T20. The emitter of the transistor T20 is connected to the power line 23.

  When a drive signal (H level on signal) is output from the F / V conversion circuit 15, the relay drive circuit 14 turns on the transistor T10 and turns on the transistor T20, and the power from the battery (power supply voltage) VB) is supplied to the IG relay 11 via the power supply lines 23 and 20 and the power supply output terminal 21. Thereby, IG relay 11 will be in an operation state, and electric power (power supply voltage VB) will be supplied to an electric component required for driving maintenance of vehicles.

  On the other hand, when an L level off signal is output from the F / V conversion circuit 15, both the transistor T10 and the transistor T20 are turned off, and the supply of power (power supply voltage VB) from the battery to the IG relay 11 is interrupted. . As a result, the IG relay 11 is deactivated, and the supply of power (power supply voltage VB) from the battery to the electrical components necessary for maintaining the running of the vehicle is interrupted.

  In the power supply switching device 10 having the above configuration, the relay drive circuit 13 is controlled by the microcomputer 12, and the relay drive circuit 14 is controlled by the F / V conversion circuit 15. The operation of the power supply switching device 10 will be described with reference to FIG.

  When a drive signal (H level on signal) is output from the microcomputer 12 to the relay drive circuit 13 by turning on an ignition switch or a start switch (not shown) at time t1 in FIG. 3, the relay drive is performed as described above. The transistors T1 and T2 of the circuit 13 are both turned on, the relay drive circuit (relay drive circuit A) 13 is changed from the non-operation state (OFF) to the operation state (ON), and the IG relay 11 is changed from the non-operation state (OFF). The operation state (ON) is established, and the electric power (power supply voltage VB) from the battery is supplied to the electrical components necessary for maintaining the running of the vehicle.

  When the vehicle starts running at time t2 in FIG. 3 and an H level vehicle speed pulse 17 is output from the vehicle speed sensor 16 to the signal input terminal 24, a drive signal (H Level ON signal) is output. Thereby, the transistors T10 and T20 of the relay drive circuit 14 are both turned on, and the relay drive circuit (relay drive circuit B) 14 is changed from the non-operating state (OFF) to the operating state (ON). As a result, the operating state of the IG relay 11 is maintained not only by the relay drive circuit 13 but also by the relay drive circuit 14 while the vehicle is traveling.

  When the vehicle stops at time t3 in FIG. 3, the vehicle speed pulse 17 becomes L level, and the vehicle speed pulse 17 is not input to the F / V conversion circuit 15, and the L / level is sent from the F / V conversion circuit 15 to the relay drive circuit 14. Off signal is output. Thereby, the relay drive circuit 14 changes from the operating state (ON) to the non-operating state (OFF).

  When the vehicle starts running again at time t4 in FIG. 3, an H level ON signal is output from the F / V conversion circuit 15 to the relay drive circuit 14, so that the relay drive circuit 14 is again set to the operating state (ON). Even during this traveling, the operating state of the IG relay 11 is maintained not only by the relay drive circuit 13 but also by the relay drive circuit 14.

  When the vehicle stops at time t5 in FIG. 3, an L level off signal is output from the F / V conversion circuit 15 to the relay drive circuit 14, so that the relay drive circuit 14 is in a non-operating state (OFF).

  When the vehicle starts running again at time t6 in FIG. 3, an H level ON signal is output from the F / V conversion circuit 15 to the relay drive circuit 14, so that the relay drive circuit 14 returns to the operating state (ON). Even during this traveling, the operating state of the IG relay 11 is maintained not only by the relay drive circuit 13 but also by the relay drive circuit 14.

  When the vehicle stops at time t7 in FIG. 3, an L level off signal is output from the F / V conversion circuit 15 to the relay drive circuit 14, so that the relay drive circuit 14 becomes non-operating (OFF).

  At time t8 in FIG. 3, when an L level off signal is output from the microcomputer 12 to the relay drive circuit 13 by turning off the ignition switch or start switch, both the transistors T1 and T2 of the relay drive circuit 13 are turned off. Then, the relay drive circuit 13 becomes inactive (OFF), the IG relay 11 becomes inactive (OFF), and power from the battery (power supply voltage VB) is supplied to the electrical components necessary for maintaining the running of the vehicle. It will not be done.

According to the embodiment configured as described above, the following operational effects can be obtained.
The relay drive circuit 13 is controlled by the microcomputer 12. Further, while the vehicle speed pulse 17 is being input to the F / V conversion circuit 15, the relay drive circuit 14 operates the IG relay 11 by the drive signal (L level off signal) output from the F / V conversion circuit 15. Let In this way, the relay drive circuit 14 is during the time when the vehicle speed pulse 17 is input to the F / V conversion circuit 15 (time t2 to time t3, time t4 to time t5, time t6 to time t7 in FIG. 3), that is, During the traveling of the vehicle, the IG relay 11 is held in the operating state by being driven by the F / V conversion circuit 15. Thereby, when there is a vehicle speed, the IG relay 11 can be driven in a double system.
The power switching device 10 that can drive the IG relay 11 in a double system can be realized with a simple configuration in which the relay drive circuit 14 is controlled by the F / V conversion circuit 15 to which the vehicle speed pulse 17 is input.
The vehicle speed pulse 17 is input to the F / V conversion circuit 15 without going through the microcomputer 12, and the relay drive circuit 14 is switched by the F / V conversion circuit 15 while the vehicle speed pulse 17 is input to the F / V conversion circuit 15. Since the IG relay 11 is driven and held in the operating state, the IG relay 11 can be held in the operating state even when the microcomputer 12 breaks down. Thereby, reliability is improved.
○ Power supply switching that can drive the IG relay 11 that switches the power supply to the electrical components necessary for maintaining the vehicle running in a duplex system while driving, simplifying the circuit and improving reliability The device 10 can be realized.

  Note that the vehicle power supply switching device according to the present invention is for any type of vehicle that switches the operation state of the IG relay 11 by operating the ignition switch and the type that switches the operation state of the IG relay 11 by operating the start switch. It can also be applied to a power switching device.

1 is a block diagram showing a schematic configuration of a vehicle power supply switching device according to an embodiment of the present invention. The circuit diagram which shows the detailed circuit structure of the F / V conversion circuit and two relay drive circuits which are shown in FIG. The timing chart which shows operation | movement of the vehicle power supply switching device which concerns on one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Power supply switching apparatus for vehicles 11 ... IG relay 12 ... Microcomputer 13 ... Relay drive circuit (relay drive circuit A)
14 ... Relay drive circuit (Relay drive circuit B)
DESCRIPTION OF SYMBOLS 15 ... F / V conversion circuit 16 ... Vehicle speed sensor 17 ... Vehicle speed pulse 24 ... Signal input terminal

Claims (1)

A vehicle power source switching device for switching a switching means for switching power supply from a battery to an electrical component necessary for maintaining traveling of the vehicle between an operating state and a non-operating state,
First power switching means and second power switching means for operating the switching means,
Control means for controlling the first power supply switching means;
An F / V conversion circuit to which a vehicle speed pulse is input,
The vehicle power supply switching device, wherein the F / V conversion circuit outputs a drive signal to the second power supply switching means to operate the switching means while a vehicle speed pulse is input.

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