JP2016175617A - Display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device for a vehicle, which contributes to power saving when control means in a quiescent mode in which processing load is small, and which facilitates noise countermeasure when the control means in an operation mode in which processing load is large.SOLUTION: A display device 1A for a vehicle according to the present invention comprises: display means 10; control means 11 that displays vehicle information on the display means 10; and a constant-voltage circuit 12 that voltage-transforms power of an on-vehicle battery 2 and supplies the power to the control means 11. A constant voltage circuit 12 has a switching regulator 120 that supplies power in a pulse width modulation system and a pulse frequency modulation system. The constant voltage circuit 120 supplies power in the pulse width modulation system when the control means 11 is in an operation mode in which vehicle information is displayed on the display means 10, and supplies power in the pulse frequency modulation system when the control means 11 is in a quiescent mode in which display of vehicle information on the display means 10 is made quiescent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicular display device that switches between a pause mode in which operation is paused and an operation mode.

  This type of vehicle display device is disclosed in Patent Document 1, for example. This vehicle display device includes a display unit (liquid crystal display device) for displaying vehicle information, a control unit (control unit) for controlling the display unit, and a voltage suitable for the control unit with the electric power of the on-vehicle battery. And a constant voltage circuit to be supplied in order to save power by switching between a sleep mode in which the operation of the control means is suspended and an operation mode in accordance with switching of the ignition switch.

JP 2004-224132 A

  However, when a switching power supply circuit is used for the constant voltage circuit that converts the power of the on-vehicle battery into a voltage suitable for the control means and supplies the voltage to the control means, if the same conversion method is always used, the sleep mode with a small processing load is set. There is a problem that noise conversion countermeasures become difficult because noise due to the switching frequency cannot be specified when in an operation mode in which the power conversion efficiency drops or the processing load varies.

  The present invention has been made in view of the above circumstances, and contributes to power saving when the control means is in a sleep mode with a small processing load, and for vehicles that are easy to take measures against noise when in an operation mode with a large processing load. An object is to provide a display device.

A vehicle display device according to the present invention includes:
Display means;
Control means for displaying vehicle information on the display means;
A constant voltage circuit that transforms the power of the vehicle battery and supplies the control means with power, and
The constant voltage circuit has a switching regulator that supplies power by a pulse width modulation method and a pulse frequency modulation method,
The constant voltage circuit supplies power by the pulse width modulation method in an operation mode in which the control means displays the vehicle information on the display means,
A first feature is that the control means supplies power by the pulse frequency modulation method in a pause mode in which the display of the vehicle information on the display means is paused.

The vehicle display device according to the present invention includes:
Display means;
Control means for displaying vehicle information on the display means;
A constant voltage circuit that transforms the power of the vehicle battery and supplies the control means with power, and
The constant voltage circuit includes a switching regulator that supplies power by a pulse width modulation method, and a linear regulator,
The constant voltage circuit supplies power from the switching regulator in an operation mode in which the control means displays the vehicle information on the display means,
The control unit supplies power from the linear regulator in a sleep mode in which display of the vehicle information on the display unit is stopped.

Further, the control means of the vehicle display device having the first feature or the second feature according to the present invention outputs a switching signal to the constant voltage circuit,
A third feature is that the constant voltage circuit switches a method of supplying power to the control means when the switching signal is input.

  According to the present invention, it is possible to provide a vehicle display device that contributes to power saving when the control means is in a sleep mode with a small processing load, and that can easily take measures against noise when in an operation mode in which the processing load varies.

It is an electrical block diagram of the display apparatus for vehicles which is 1st Embodiment of this invention. It is a figure which shows switching of the power supply to the control means of the display apparatus for vehicles of the embodiment. It is an electrical block diagram of the display apparatus for vehicles which is 2nd Embodiment of this invention. It is a figure which shows switching of the power supply to the control means of the display apparatus for vehicles of the embodiment.

  An embodiment of a vehicle display device to which the present invention is applied will be described below with reference to the accompanying drawings.

(First embodiment)
A vehicle display device 1A according to a first embodiment to which the present invention is applied will be described with reference to FIGS.
The vehicle display device 1A according to the first embodiment to which the present invention is applied is driven by being supplied with electric power from an in-vehicle battery 2 mounted on the vehicle, and the vehicle travel distance, engine speed, etc. input from the input means 3 It is an instrument that displays various vehicle information.

  As shown in FIG. 1, the vehicle display device 1 </ b> A includes a display unit 10, a control unit 11, and a constant voltage circuit 12.

  The display means 10 is an image display such as a liquid crystal display, for example, and displays an image representing various vehicle information input from the input means 3.

  The control means 11 is a circuit board on which a microcomputer that is driven with a voltage different from the output voltage of the in-vehicle battery 2 is mounted, and controls the entire vehicle display device 1A. The control means 11 periodically receives vehicle information consisting of the vehicle running speed, engine speed, various warning information, etc. from the in-vehicle LAN 3 and causes the display means 10 to display an image on the vehicle information.

  The control unit 11 can switch between a sleep mode in which the operation is stopped and power consumption is reduced, and an operation mode. When the control unit 11 enters the operation mode, vehicle information including a vehicle traveling speed, an engine speed, various warning information, and the like is periodically input from the in-vehicle LAN 3, and the vehicle information is input to the display unit 10 at a predetermined update period. Display an image. Moreover, the control means 11 will stop the image display on the display means 10, and will reduce power consumption, if it will be in a sleep mode. The switching between the operation mode and the sleep mode is started by inputting a wake-up request / pause request from the in-vehicle LAN 3, and the control means 11 performs initialization (Initialization) or end processing (Finalization) when these requests are input. ) Is switched to the operation mode or the sleep mode. The control unit 11 outputs a power supply method switching signal to the constant voltage circuit 12 when switching to the operation mode or the sleep mode. This series of processing will be described in detail later.

  The constant voltage circuit 12 is a power supply circuit connected to the in-vehicle battery 2 and is mounted on the same circuit board as the control means 11. The constant voltage circuit 12 includes a switching regulator 120 and a delay circuit 121.

  The switching regulator 120 steps down the 12 V (volt) power supplied from the in-vehicle battery 2 to 5 V (volt) of the drive voltage of the control means 11 and supplies the voltage to the control means 11. The switching regulator 120 can select power supply by a PWM (pulse width modulation) method or a PFM (pulse frequency modulation) method and stop of power supply. The delay circuit 121 is a circuit that gives a time delay to the input signal and outputs the delayed signal. The delay circuit 121 delays the power supply switching signal input from the control unit 11 and outputs the delayed signal to the switching regulator 120. When the switching signal of the power supply method is input from the delay circuit 121, the switching regulator 120 switches the power supply to the control means 11 to any one of the PWM method / PFM method / supply stop.

  The switching of the power supply method of the constant voltage circuit 12 accompanying the switching between the operation mode and the pause mode of the control means 11 will be described with reference to FIG.

  The control means 11 in the sleep mode is supplied with power by the PFM method from the switching regulator 120 of the constant voltage circuit 12. The switching regulator 120 can efficiently convert the power supplied from the in-vehicle battery 2 by supplying power with the PFM method when the control unit 11 is in the sleep mode with a small processing load. When power is supplied by the PFM method, if the processing load of the control unit 11 fluctuates, the switching frequency fluctuates and it becomes difficult to specify the noise frequency. However, when the control unit 11 enters the sleep mode, the processing load becomes approximately constant. Therefore, the switching frequency is also approximately constant, and the noise frequency can be specified.

  When the wake-up request is input from the in-vehicle LAN 3 at time T1, the control unit 11 in the sleep mode switches itself from the sleep mode to the operation mode, performs initialization processing, and then updates the vehicle information at a predetermined update period. Instrument display for displaying an image on the display means 10 is started. The initialization process is a process of reading information such as a total travel distance saved by an end process, which will be described later, and a past fuel consumption history, from a non-volatile memory such as a flash memory. It is preferable to perform the display accompanied by a display for notifying the start of the instrument display. The control unit 11 outputs a switching signal for switching the power supply method of the switching regulator 120 from the PFM method to the PWM method to the delay circuit 121 of the constant voltage circuit 12. The switching regulator 120 switches the power supply method to the control unit 11 to the PWM method in accordance with the switching signal input from the delay circuit 121. When the control unit 11 is in the operation mode, the switching regulator 120 can supply power in a PWM manner so that appropriate power supply can be performed with high responsiveness to fluctuations in the processing load of the control unit 11. Further, since power is supplied by the PWM method, the noise frequency in the power supply is limited to a specific frequency band, and noise countermeasures are facilitated.

  When the stop request is input from the in-vehicle LAN 3 at time T2, the control means 11 that performs the instrument display in the operation mode stops the instrument display and performs a termination process. This termination process is a process of storing the total travel distance of the vehicle calculated from the vehicle information input from the in-vehicle LAN 3 and the past fuel consumption history in a non-volatile memory such as a flash memory. It is preferable to perform display accompanied by a display notifying the end of the instrument display such as “BYE”. When the end process is finished (time T3), the control unit 11 switches itself from the operation mode to the pause mode. Accordingly, the control means 11 outputs a switching signal for switching the power supply method of the switching regulator 120 from the PWM method to the PFM method to the delay circuit 121 of the constant voltage circuit 12. The switching regulator 120 switches the power supply method to the control unit 11 to the PFM method in accordance with the switching signal input from the delay circuit 121.

(Operations and effects in the first embodiment described above)
The vehicle display device 1A according to the first embodiment to which the present invention having the above-described configuration is applied includes a display means 10, a control means 11 for displaying vehicle information on the display means 10, and a power of the in-vehicle battery 2 being transformed. A constant voltage circuit 12 that supplies power to the control means 11, and the constant voltage circuit 12 includes a switching regulator 120 that supplies power using a pulse width modulation method and a pulse frequency modulation method. The constant voltage circuit 120 supplies power in a pulse width modulation method when the control unit 11 is in an operation mode in which vehicle information is displayed on the display unit 10, and the control unit 11 stops displaying vehicle information on the display unit 10. Electric power is supplied by a pulse frequency modulation method in the sleep mode.
According to this, when the control means 11 is in the sleep mode with a small processing load, the switching regulator 120 supplies power to the control means 11 by the PFM (pulse frequency modulation) method, so that the power supplied from the in-vehicle battery 2 can be efficiently obtained. Can be converted. In addition, when the control unit 11 is in the sleep mode, the processing load is almost constant, and noise countermeasures are easy even when power is supplied by the PFM method. In addition, when the control unit 11 is in the operation mode, by supplying power by a PWM (pulse width modulation) method, appropriate power supply can be performed with good responsiveness to fluctuations in the processing load of the control unit 11. Further, since power is supplied by the PWM method, the noise frequency in the power supply is limited to a specific frequency band, and noise countermeasures are facilitated. As a result, it is possible to provide a vehicle display device that contributes to power saving when the control means is in the sleep mode with a small processing load, and that can easily take measures against noise when in the operation mode with a large processing load.

  The vehicle display device 1A according to the first embodiment to which the present invention is applied has been described above. However, the present invention may be configured as a vehicle display device 1B according to a second embodiment described below.

(Second Embodiment)
A vehicle display device 1B according to a second embodiment to which the present invention is applied will be described with reference to FIGS.
As shown in FIG. 3, the vehicle display device 1B is different in configuration from the constant voltage circuit 12 of the vehicle display device 1A according to the first embodiment described above.

  The constant voltage circuit 12 is a power supply circuit connected to the in-vehicle battery 2 and is mounted on the same circuit board as the control means 11. The constant voltage circuit 12 includes a switching regulator 120, a delay circuit 121, and a linear regulator 122.

  The linear regulator 122 is a step-down circuit composed of a low drop-out regulator.

  The constant voltage circuit 12 steps down the 12 V (volt) power supplied from the in-vehicle battery 2 to 5 V (volt) of the drive voltage of the control means 11 by the switching regulator 120 or the linear regulator 122 and supplies it to the control means 11. To do. The switching of the power supply source (switching regulator 120 or linear regulator 122) to the control unit 11 is performed in accordance with the switching between the operation mode and the suspension mode of the control unit 11.

  The switching of the power supply of the constant voltage circuit 12 that accompanies switching between the operation mode and the pause mode of the control means 11 will be described with reference to FIG.

  When the control unit 11 is in the sleep mode, the switching regulator 120 stops power supply in response to the switching signal output from the control unit 11 and is supplied with power from the linear regulator 122. Since the linear regulator 122 is composed of a low-loss regulator, it can efficiently convert the power supplied from the in-vehicle battery 2 and supply it to the control means 11. The linear regulator 122 has low noise, has a relatively small mounting area, and is inexpensive. In particular, the linear regulator 122 corresponding to a small processing load when the control unit 11 is in the sleep mode is easy to introduce because it has a small mounting area and is inexpensive.

  When the wake-up request is input from the in-vehicle LAN 3 at time T1, the control unit 11 in the sleep mode switches itself from the sleep mode to the operation mode, performs initialization processing, and then updates the vehicle information at a predetermined update period. Instrument display for displaying an image on the display means 10 is started. The initialization process is a process of reading information such as a total travel distance saved by an end process, which will be described later, and a past fuel consumption history, from a non-volatile memory such as a flash memory. It is preferable to perform the display accompanied by a display for notifying the start of the instrument display. Further, the control unit 11 outputs a switching signal for switching the power supply method of the switching regulator 120 from the power supply stop to the start of the power supply by the PWM method to the delay circuit 121 of the constant voltage circuit 12. In response to the switching signal input from the delay circuit 121, the switching regulator 120 starts supplying power to the control unit 11 in the PWM method. As a result, the control unit 11 switches from power supply by the linear regulator 122 to power supply by the switching regulator 120. When the control unit 11 enters the operation mode, power is supplied from the switching regulator 120 in a PWM manner, so that appropriate power supply can be performed with good responsiveness to fluctuations in the processing load of the control unit 11. Further, since power is supplied by the PWM method, the noise frequency in the power supply is limited to a specific frequency band, and noise countermeasures are facilitated.

  When the stop request is input from the in-vehicle LAN 3 at time T2, the control means 11 that performs the instrument display in the operation mode stops the instrument display and performs a termination process. This termination process is a process of storing the total travel distance of the vehicle calculated from the vehicle information input from the in-vehicle LAN 3 and the past fuel consumption history in a non-volatile memory such as a flash memory. It is preferable to perform display accompanied by a display notifying the end of the instrument display such as “BYE”. When the end process is finished (time T3), the control unit 11 switches itself from the operation mode to the pause mode. Accordingly, the control unit 11 stops the power supply from the switching regulator 120 of the constant voltage circuit 12 and switches to the power supply from the linear regulator 122 again.

(Operations and effects in the second embodiment described above)
The vehicle display device 1B according to the second embodiment to which the present invention having the above configuration is applied includes a display unit 10, a control unit 11 for displaying vehicle information on the display unit 10, and a power of the in-vehicle battery 2 being transformed. A constant voltage circuit 12 that supplies power to the control means 11, and the constant voltage circuit 12 includes a switching regulator 120 that supplies power by a pulse width modulation method, and a linear regulator 122. The constant voltage circuit 12 supplies power from the switching regulator 120 in the operation mode in which the control unit 11 displays the vehicle information on the display unit 10, and the control unit 11 pauses the display of the vehicle information on the display unit 10. Electric power is supplied from the linear regulator 122 in the mode.
According to this, when the control unit 11 is in the sleep mode with a small processing load, the power supplied from the in-vehicle battery 2 can be efficiently converted by supplying power from the linear regulator 122 to the control unit 11. In addition, when the control unit 11 is in the operation mode, by supplying power from the switching regulator 120 by a PWM (pulse width modulation) method, appropriate power supply can be performed with good response to fluctuations in the processing load of the control unit 11. Further, since power is supplied by the PWM method, the noise frequency in the power supply is limited to a specific frequency band, and noise countermeasures are facilitated. As a result, it is possible to provide a vehicle display device that contributes to power saving when the control means is in the sleep mode with a small processing load, and that can easily take measures against noise when in the operation mode with a large processing load.

  The vehicle display device 1B according to the second embodiment to which the present invention is applied has been described above.

  The present invention can add changes (including deletion of components) to the embodiments and the drawings without departing from the gist of the present invention.

  The control means 11 switches itself between the sleep mode and the operation mode in response to a pause or wake-up request input from the in-vehicle LAN 3, but the control means 11 is not limited to this, and the control means 11 The sleep mode and the operation mode may be switched based on various information such as opening / closing of the door, locking / unlocking, or the sitting state of the passenger.

  The constant voltage circuit 12 includes a delay circuit 121 that gives a time delay to the switching signal input from the control unit 11 and outputs the delayed signal to the switching regulator 120. However, the present invention is not limited to this. A delay circuit that gives a time delay to the wiring for supplying power from the switching regulator 120 to the control means 11 may be provided. These delay circuits contribute to preventing problems caused by the switching of the power supply method during a period in which the state until the control unit 11 completes switching between the sleep mode and the operation mode is indefinite.

  The present invention is suitable for a display device mounted on a vehicle.

DESCRIPTION OF SYMBOLS 1A: Display apparatus for vehicles 1B: Display apparatus for vehicles 10: Display means 11: Control means 12: Constant voltage circuit 120: Switching regulator 121: Delay circuit 122: Linear regulator 2: Car battery 3: Car LAN

Claims (3)

Display means;
Control means for displaying vehicle information on the display means;
A constant voltage circuit that transforms the power of the vehicle battery and supplies the control means with power, and
The constant voltage circuit has a switching regulator that supplies power by a pulse width modulation method and a pulse frequency modulation method,
The constant voltage circuit supplies power by the pulse width modulation method in an operation mode in which the control means displays the vehicle information on the display means,
The vehicle display device, wherein the control means supplies power by the pulse frequency modulation method in a pause mode in which the display of the vehicle information on the display means is paused. Display means;
Control means for displaying vehicle information on the display means;
A constant voltage circuit that transforms the power of the vehicle battery and supplies the control means with power, and
The constant voltage circuit includes a switching regulator that supplies power by a pulse width modulation method, and a linear regulator,
The constant voltage circuit supplies power from the switching regulator in an operation mode in which the control means displays the vehicle information on the display means,
The vehicle display device, wherein the control means supplies power from the linear regulator in a sleep mode in which the display of the vehicle information on the display means is paused. The control means outputs a switching signal to the constant voltage circuit,
The vehicle display device according to claim 1, wherein the constant voltage circuit switches a method of supplying power to the control unit when the switching signal is input.

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