Display device for vehicle

Abstract

To provide a display device for a vehicle that can achieve a simplified configuration while suppressing heat generation.SOLUTION: A display device 10 for a vehicle includes: a display unit 14; a control unit 12 that controls the display unit 14; a microcomputer power supply generation circuit 7 that transforms received power and supplies it to the control unit 12; a battery line Lb that supplies power to the microcomputer power supply generation circuit 7; an ignition line Li that supplies power to the microcomputer power supply generation circuit 7; an ideal diode 3 that has a MOSFET 4 provided on the battery line Lb in a forward direction toward the microcomputer power supply generation circuit 7; and a rectifying diode 6 that is provided on the ignition line Li in a forward direction toward the microcomputer power supply generation circuit 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a display device for a vehicle. [Background technology]

[0002] The instrument device described in Patent Document 1 uses rectifier diodes (diodes 1a and 1b in Patent Document 1) to prevent malfunction when a battery is connected in reverse. The reverse current suppression circuit described in Patent Document 2 uses an ideal diode that cuts off reverse current to the battery by turning off a field effect transistor (FET) element (FET element Q1 in Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-62655 A [Patent Document 2] JP 2019-134580 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above rectifier diode has a simple configuration but the disadvantage of heat generation. The above ideal diode has the advantage of suppressing heat generation, but the disadvantage is that the configuration requires FET switching, making it complicated. For this reason, in a configuration with multiple power supplies for redundant design, it was difficult to prevent backflow while simultaneously achieving a simple configuration and suppressing heat generation.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and has an object to provide a vehicle display device that can realize a simple configuration while suppressing heat generation. [Means for solving the problem]

[0006] In order to achieve the above object, the vehicle display device according to the present disclosure includes: A display device; A control unit for controlling the display device; a power generation circuit that transforms the received power and supplies it to the control unit; a main power line for supplying power to the power generation circuit; a first sub-power line that supplies power to the power generation circuit; an ideal diode having a MOSFET provided on the main power line so that the forward direction of the MOSFET is toward the power generation circuit; a first rectifier diode provided on the first sub-power line so as to be oriented in a forward direction toward the power generation circuit. Effect of the Invention

[0007] According to the present disclosure, a simple configuration can be realized while suppressing heat generation. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram of a vehicle display device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 11 is a block diagram of a display device for a vehicle according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) A vehicle display device according to a first embodiment of the present disclosure will be described with reference to the drawings. The vehicle display device is a digital meter that is mounted on a motorcycle and displays an image including vehicle information.

[0010] 1, a vehicle display device 10 includes a main power supply 1, a sub-power supply 2, an ideal diode 3, a rectifier diode 6, a microcomputer power generation circuit 7, a microcomputer (microcomputer) 11, and a load 17. The load 17 includes a display 14, an illumination unit 15, and a sound unit 16. The ideal diode 3 and the rectifier diode 6 form a reverse connection protection circuit.

[0011] The illumination unit 15 is configured by a circuit board on which a plurality of light sources, that is, LEDs (Light Emitting Diodes), are mounted. The illumination unit 15 is controlled by the microcomputer 11 and illuminates the display 14.

[0012] The display 14 is a TFT (Thin Film Transistor) liquid crystal panel controlled by the microcomputer 11. The display 14 receives illumination light and displays an image showing vehicle information. The sound generating unit 16 is a speaker, and is controlled by the microcomputer 11 to emit warning sounds, voices, and the like.

[0013] The main power supply 1 is a battery power supply that supplies power from an in-vehicle battery (not shown), and is configured to be able to supply power to a microcomputer power generation circuit 7 via an ideal diode 3. The ideal diode 3 is provided on a battery line Lb that serves as a power supply line from the main power supply 1. The main power supply 1 constantly applies a voltage V1 to the battery line Lb.

[0014] The sub-power supply 2 is an ignition power supply connected to an in-vehicle battery via an ignition switch (not shown) that is switched between on and off by a user's operation. The sub-power supply 2 is configured to be able to supply power to a microcomputer power supply generating circuit 7 via a rectifier diode 6 when the main power supply 1 fails. The rectifier diode 6 is provided on an ignition line Li serving as a power supply line from the sub-power supply 2. The sub-power supply 2 applies a voltage V2 to the ignition line Li when an ignition switch (not shown) is on, and stops applying the voltage V2 to the ignition line Li when the ignition switch (not shown) is off. Voltage V1 and voltage V2 are almost the same voltage, for example, 13 V. To be precise, when main power supply 1 is normal, voltage V1 of main power supply 1 is higher than voltage V2 of sub-power supply 2, which is dropped by an ignition switch (not shown).

[0015] The ideal diode 3 is electrically connected between the main power supply 1 and the microcomputer power supply generating circuit 7, and is provided so that the forward direction of the ideal diode 3 faces the microcomputer power supply generating circuit 7. The ideal diode 3 prevents reverse current flow to the main power supply 1 due to reverse connection of the positive and negative terminals of the vehicle battery, etc. The ideal diode 3 includes an N-channel MOSFET 4 and a FET controller 5. The FET controller 5 switches the MOSFET 4 between on and off by controlling the switching of the MOSFET 4 under the control of the microcomputer 11. When the input voltage from the main power supply 1 is higher than the output voltage to the microcomputer power generation circuit 7, the FET controller 5 turns on the MOSFET 4 to enable current supply from the main power supply 1 to the microcomputer 11. On the other hand, when the output voltage is equal to or higher than the input voltage, the FET controller 5 turns off the MOSFET 4 to block reverse current flow from the microcomputer power generation circuit 7 to the main power supply 1. In the ideal diode 3, the forward voltage drop (voltage loss) can be made substantially zero.

[0016] The rectifier diode 6 is electrically connected between the sub-power supply 2 and the microcomputer power supply generating circuit 7, and is provided so that the forward direction (direction from anode to cathode) of the rectifier diode 6 faces the microcomputer power supply generating circuit 7. The rectifier diode 6 is composed of one discrete component. The cathode terminal of the rectifier diode 6 is connected to the microcomputer power supply generating circuit 7, and the anode terminal of the rectifier diode 6 is connected to the sub-power supply 2. The rectifier diode 6 enables current supply from the sub-power supply 2 to the microcomputer 11, while blocking reverse current flow from the microcomputer power supply generating circuit 7 to the sub-power supply 2 due to reverse connection of the positive and negative terminals of the vehicle battery, etc. In the rectifier diode 6, the voltage drop (voltage loss) of the forward voltage is not zero, and the voltage drop in the rectifier diode 6 is larger than the voltage drop in the ideal diode 3.

[0017] The microcomputer power generation circuit 7 is electrically connected between the ideal diode 3 and the rectifier diode 6 and the microcomputer 11. The microcomputer power generation circuit 7 is made up of a DC-DC converter, and steps down the voltages V1 and V2 from the main power supply 1 or the sub-power supply 2, for example, stepping down 13 V to 5 V or 3.3 V, and applies it to the microcomputer 11 as an operating power supply.

[0018] The microcomputer 11 operates by receiving power from the microcomputer power generation circuit 7, and controls the display 14, the illumination unit 15, and the sound unit 16. The microcomputer 11 has a signal input terminal (not shown) for inputting an ignition signal indicating the on / off state of the ignition. The microcomputer 11 starts up when the ignition is switched from off to on based on the ignition signal, and shuts down when the ignition is switched from on to off based on the ignition signal.

[0019] The microcomputer 11 includes a main voltage detection unit 8 , a sub-voltage detection unit 9 , a power supply state determination unit 18 , and a control unit 12 . The main voltage detection unit 8 detects the voltage V1 applied by the main power supply 1 to the battery line Lb, and outputs a detection signal indicating this detection result to the power supply state determination unit 18. Specifically, the main voltage detection unit 8 reads the voltage value (detection signal) obtained by dividing the voltage V1 applied by the main power supply 1 by a voltage dividing resistor (not shown), and detects the voltage V1 applied by the main power supply 1 based on this read voltage value.

[0020] The sub-voltage detection unit 9 detects the voltage V2 applied by the sub-power supply 2 to the ignition line Li, and outputs a detection signal indicating this detection result to the power supply state determination unit 18. Specifically, the sub-voltage detection unit 9 reads the voltage value (detection signal) obtained by dividing the voltage V2 applied by the sub-power supply 2 by a voltage dividing resistor (not shown), and detects the voltage applied by the sub-power supply 2 based on this read voltage value.

[0021] The power supply state determination unit 18 determines whether there is an abnormality in the main power supply 1 based on the detection results of the voltage detection units 8 and 9. Specifically, when the voltage V1 applied by the main power supply 1 is higher than the voltage V2 applied by the sub-power supply 2, that is, when "V2 < V1" holds, the power supply state determination unit 18 determines that there is no abnormality in the main power supply 1. Also, when the voltage V2 applied by the sub-power supply 2 is higher than the voltage V1 applied by the main power supply 1, that is, when "V2 > V1" holds, the power supply state determination unit 18 determines that there is an abnormality in the main power supply 1. The voltage drop in the rectifying diode 6 is larger in amount than the voltage drop in the ideal diode 3. In other words, the resistance value of the rectifying diode 6 is larger than the resistance value of the ideal diode 3. For this reason, when the main power supply 1 is normal, current preferentially flows from the main power supply 1 to the microcomputer power generation circuit 7, and no current flows from the sub-power supply 2 to the microcomputer power generation circuit 7. On the other hand, when the main power supply 1 is abnormal, current no longer flows normally from the main power supply 1 to the microcomputer power generation circuit 7, and current flows from the sub-power supply 2 to the microcomputer power generation circuit 7.

[0022] When power supply state determination unit 18 determines that there is no abnormality, control unit 12 operates in a normal power consumption mode to control load 17 (display unit 14, illumination unit 15, and sound unit 16). Furthermore, when the power supply state determination unit 18 determines that there is an abnormality, the control unit 12 turns off the MOSFET 4 and operates in a low power consumption mode that consumes less power than the normal power consumption mode to control the load 17 (the display 14, the illumination unit 15, and the sound unit 16). In the low power consumption mode, the microcomputer 11 operates in an energy saving mode. In the energy saving mode of the microcomputer 11, well-known energy saving techniques are implemented, such as lowering the operating frequency, reducing the number of functions in operation, and lengthening the sleep time.

[0023] Furthermore, in the low power consumption mode, the control unit 12 may execute a combination of one or more of the following processes (a) to (e) with respect to the control of the load 17. (a) Processing for lowering the light emission luminance of the illumination unit 15 to a level lower than that in the normal power consumption mode (b) A process of reducing the number of light sources that constitute the illumination unit 15 to be turned on compared to the normal power consumption mode. (c) Processing for lowering the display resolution of the display 14 to a level lower than that in the normal power consumption mode (d) A process of making the display size on the display unit 14 smaller than that in the normal power consumption mode. (e) Processing for reducing the volume of the sound emitted by the sound generating unit 16 to a level lower than that in the normal power consumption mode.

[0024] Next, the operation of the vehicle display device 10 will be described. The ideal diode 3 has a smaller voltage drop than the rectifier diode 6. Therefore, when the main power supply 1 and the sub-power supply 2 are normal, power from the main power supply 1 is supplied to the microcomputer power supply generating circuit 7 via the ideal diode 3, and power from the sub-power supply 2 is not supplied to the microcomputer power supply generating circuit 7. Therefore, under normal conditions, no current flows through the rectifier diode 6, and the rectifier diode 6 does not generate heat. On the other hand, when the main power supply 1 fails, power from the sub power supply 2 is supplied to the microcomputer power generation circuit 7 via the rectifier diode 6. Therefore, the microcomputer 11 operates even when the main power supply 1 fails. When the main power supply 1 fails, current flows through the rectifier diode 6, generating heat, but since the rectifier diode 6 is only used when the main power supply 1 fails, it is used less frequently than the ideal diode 3. By employing the rectifier diode 6 instead of the ideal diode as the diode that is used less frequently, a simple configuration can be achieved.

[0025] (effect) According to the first embodiment described above, the following effects are achieved. (1) The vehicle display device 10 includes a display 14, a control unit 12 that controls the display 14, a microcomputer power generation circuit 7 that is an example of a power generation circuit that transforms received power and supplies it to the control unit 12, a battery line Lb that is an example of a main power line that supplies power to the microcomputer power generation circuit 7, an ignition line Li that is an example of a first sub-power line that supplies power to the microcomputer power generation circuit 7, an ideal diode 3 having a MOSFET 4 that is a type of field effect transistor and arranged on the battery line Lb in a forward direction toward the microcomputer power generation circuit 7, and a rectifier diode 6 that is an example of a first rectifier diode and arranged on the ignition line Li in a forward direction toward the microcomputer power generation circuit 7. According to this configuration, in a configuration having a redundant design that allows power to be supplied to the microcomputer power generation circuit 7 from any of the multiple lines Li and Lb, in order to suppress reverse current flow, an ideal diode 3 that does not easily generate heat is provided on the frequently used battery line Lb, and a rectifier diode 6 with a simple configuration is provided on the infrequently used ignition line Li. This makes it possible to realize a simple configuration while suppressing heat generation, as described above.

[0026] (2) The battery line Lb is a power line through which power from the vehicle battery flows directly, and the ignition line Li is a power line through which power from the vehicle battery flows via an ignition switch. According to this configuration, an ideal diode 3 is used in the battery line Lb, to which a voltage is always applied, to reduce heat generation, and a rectifier diode 6 is used in the ignition line Li, to which no voltage is applied when the ignition is off, thereby making it possible to achieve an inexpensive configuration.

[0027] (3) The vehicle display device 10 includes voltage detection units 8 and 9 that detect a voltage value applied to the battery line Lb and a voltage value applied to the ignition line Li, and a power supply state determination unit 18 that determines that the display device 10 is normal when the voltage value (V2) applied to the ignition line Li is less than the voltage value (V1) applied to the battery line Lb based on the detection results of the voltage detection units 8 and 9, and determines that the display device 10 is abnormal when the voltage value (V2) applied to the ignition line Li is equal to or greater than the voltage value (V1) applied to the battery line Lb. When the power supply state determination unit 18 determines that the display device 10 is normal, the control unit 12 controls the load 17 including the display unit 14 in a normal power consumption mode, and when the power supply state determination unit 18 determines that the display device 10 is abnormal, the control unit 12 controls the load 17 in a low power consumption mode that consumes less power than the normal power consumption mode. According to this configuration, in the event of an abnormality, the control unit 12 operates in a low power consumption mode, thereby reducing the power required for processing by the control unit 12. This makes it possible to reduce the load on the rectifier diode 6 and the heat generation.

[0028] Second embodiment A vehicle display device according to a second embodiment of the present disclosure will be described with reference to the drawings. This embodiment differs from the first embodiment in that a plurality of sub-power sources are provided. The following description will focus on the differences from the first embodiment.

[0029] As shown in FIG. 2, the vehicle display device 210 includes a plurality of sub-power sources 2 and 22, a plurality of rectifier diodes 6 and 26, and a plurality of sub-voltage detectors 9 and 29. The sub-power supply 22 and the rectifier diode 26 are connected in parallel to the sub-power supply 2 and the rectifier diode 6. The sub-power supply 22 is an ignition power supply that supplies power from an ignition switch (not shown), and is configured to be able to supply power to the microcomputer power supply generation circuit 7 via the rectifier diode 26 when an abnormality occurs in the main power supply 1. The rectifier diode 26, which is the same as the rectifier diode 6, is provided on the ignition line Lg, which serves as a power supply line from the sub-power supply 22.

[0030] The sub-power source 2 and the sub-power source 22 are ignition power sources that each supply power to a different power supply target. The sub-power source 2 supplies power to a first power supply target 31, and the sub-power source 22 supplies power to a second power supply target 32. The first power supply target 31 is a device related to vehicle running (drive system device), and the second power supply target 32 ​​is a device not related to vehicle running (accessory system device). The first power supply target 31 is, for example, an engine, a suspension, a brake, etc. The second power supply target 32 ​​is, for example, a car navigation system, an audio system, a vehicle lighting, etc.

[0031] The power supply state determination unit 18 determines that there is no abnormality in the main power supply 1 when the voltage V1 applied by the main power supply 1 is higher than the voltage V2 applied by the sub-power supply 2 or the voltage V3 applied by the sub-power supply 22. Moreover, the power supply state determination unit 18 determines that there is an abnormality in the main power supply 1 when the voltage V2 or voltage V3 is higher than the voltage V1 applied by the main power supply 1.

[0032] (effect) According to the second embodiment described above, the following effects are achieved. The vehicle display device 210 includes an ignition line Lg, which is an example of a second sub-power line that supplies power to the microcomputer power generation circuit 7, and a rectifier diode 26, which is an example of a second rectifier diode, provided on the ignition line Lg in a forward direction toward the microcomputer power generation circuit 7. According to this configuration, even if an abnormality occurs in either one of the two sub-power supplies 2, 22 in addition to an abnormality in the main power supply 1, the microcomputer 11 can operate by the power supply from the other one of the two sub-power supplies 2, 22. Therefore, a more advanced redundant design can be realized.

[0033] The present disclosure is not limited to the above-described embodiments and drawings. Modifications (including deletion of components) can be made as appropriate within the scope of the present disclosure. An example of a modification will be described below.

[0034] (Modification) In the above-described embodiments, the vehicle display device 10, 210 is mounted on a motorcycle, but may be mounted on a vehicle (including construction machinery) other than a motorcycle. The vehicle display device 10, 210 may also be combined with an analog gauge having a pointer. Moreover, the vehicle display device 10, 210 may be mounted on a head-up display device as a device that emits display light.

[0035] The voltage detection units 8, 9, and 29 and the power supply state determination unit 18 in each of the above embodiments may be configured by a comparator or the like, separate from the microcomputer 11. In the above embodiment, the display 14 may be an organic electro-luminescence display (OLED), in which case the illumination unit 15 may be omitted. [Explanation of symbols]

[0036] 1 Main power supply 2,22 Sub power supply 3 Ideal Diode 4 MOSFET 5 FET Controller 6,26 Rectifier diode 7 Microcomputer power generation circuit 8 Main voltage detector 9,29 Sub voltage detection section 10,210 Vehicle display device 11 Microcomputer 12 Control section 14 Display 15 Lighting Department 16 Fukinabu 17 Load 18 Power supply status determination unit 31 First power supply target 32 Second power supply target V1, V2, V3 voltage Lb Battery Line Lg,Li Ignition Line

Claims

1. A display device; A control unit for controlling the display device; a power generation circuit that transforms the received power and supplies it to the control unit; a main power line for supplying power to the power generation circuit; a first sub-power line for supplying power to the power generation circuit; an ideal diode having a MOSFET provided on the main power line so that the forward direction is toward the power generation circuit; a first rectifier diode provided on the first sub-power line so as to be in a forward direction toward the power generation circuit; Vehicle display device.

2. The vehicle display device includes: a second sub-power line for supplying power to the power generation circuit; a second rectifier diode provided on the second sub-power line so as to be oriented in a forward direction toward the power generation circuit; The display device for a vehicle according to claim 1 .

3. the main power supply line is a battery line through which power flows from an in-vehicle battery, The first sub-power line is an ignition line through which power from the vehicle battery flows via an ignition switch. The display device for a vehicle according to claim 1 or 2.

4. The vehicle display device includes: a voltage detection unit that detects a voltage value applied to the main power line and a voltage value applied to the first sub power line; a power supply state determination unit that determines that the power supply is normal when the voltage value applied to the first sub-power line is lower than the voltage value applied to the main power supply line based on a detection result of the voltage detection unit, and determines that the power supply is abnormal when the voltage value applied to the first sub-power line is equal to or higher than the voltage value applied to the main power supply line, When the power supply state determination unit determines that the control unit is normal, the control unit operates in a normal power consumption mode, and when the power supply state determination unit determines that the control unit is abnormal, the control unit operates in a low power consumption mode in which power consumption is smaller than that in the normal power consumption mode. The display device for a vehicle according to claim 1 or 2.

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