JP4821447B2 - In-vehicle device and vehicle navigation device - Google Patents

Description

  The present invention relates to a switching power supply that generates and supplies power for operation, a vehicle-mounted device that includes a position acquisition unit that acquires a current position of the vehicle, and a vehicle that includes the vehicle-mounted device. The present invention relates to a navigation device.

In recent years, radio timepieces that receive a standard time signal with a time code transmitted from a transmission station and automatically correct the date and time have become popular, and radio timepieces are also being mounted on vehicles. . In that case, since there are various electrical components in the passenger compartment, there is a possibility that noise generated by them may interfere with reception of the standard radio wave by the radio timepiece, and measures to avoid the occurrence of reception interference are necessary.
For example, conventional techniques related to noise countermeasures for radio-controlled timepieces prohibit the reception of standard radio waves during the operation of the chrono function (Patent Document 1), or reduce the noise level using a noise filter (Patent Document 2). There is one that detects the edge of the display control signal in the watch and temporarily prohibits reception (Patent Document 3).

Also, as a prior art specialized for a radio timepiece mounted on a vehicle, it is possible to select whether to correct reception with a full code or to correct time only for seconds with reference to the state of an ignition switch or an accessory switch (Patent Document) 4) There is one that estimates the state of the in-vehicle unit based on the fluctuation of the battery voltage and corrects the reception (Patent Document 5).
JP-A-8-201546 JP 2005-62077 A JP 2005-73223 A JP 2000-212284 A JP 2003-344666 A

  Here, for example, in a car navigation apparatus or the like, power is supplied to back up the data in the internal memory even when the accessory switch is in an off state. And in order to reduce the consumption current (dark current) of the vehicle battery when the backup power supply is generated and supplied, there are many cases where the switching power supply generates the operation power supply including the backup power supply. . In this case, since the switching power supply device generally performs a switching operation at a frequency of several kHz to several tens of kHz, the switching frequency may interfere with reception of the standard radio wave by the radio clock.

However, none of the above-described conventional techniques assumes reception interference that may occur when a switch power supply device is present, and does not contribute to the solution of the above problem.
The present invention has been made in view of the above circumstances, and an object of the present invention is to be able to avoid the occurrence of reception interference of a radio-controlled timepiece disposed in a vehicle interior even when a switching power supply device is used. An object of the present invention is to provide a vehicle navigation apparatus including the apparatus and the vehicle-mounted apparatus.

According to the in-vehicle device of the first aspect, the switching power supply device is configured such that the switching frequency is variable. Then, the power supply control means receives the switching frequency of the switching power supply device in the radio clock according to whether the position of the vehicle is a position where the radio clock can satisfactorily receive a standard radio wave transmitted from a plurality of transmitting stations. Change the setting to avoid the occurrence of interference.
That is, a plurality of standard radio wave transmitting stations exist to cover a wide area, and the radio timepiece receives any of the standard radio waves transmitted by them. Therefore, if the power control means switches the switching frequency so as to avoid the occurrence of reception interference in the radio timepiece according to the position of the vehicle, even when using the switching power supply device, the radio wave is not affected by the switching frequency. The watch can receive standard radio waves.

The power supply control means switches and sets the switching frequency according to which of the plurality of transmitting stations is near the position of the vehicle acquired by the position acquisition means. That is, it is estimated that the radio timepiece can satisfactorily receive the standard radio wave transmitted by the transmitting station with the shortest distance from the vehicle. Thus, it is possible to avoid occurrence of reception interference.

According to the in-vehicle device of the second aspect , the power supply control means switches the switching frequency of the switching power supply device so that the frequency and its harmonic series do not coincide with the transmission frequency of the standard radio wave. That is, if the switching frequency fs is set so that the frequencies fs, 2fs, 3fs, 4fs,... Do not coincide with the transmission frequency fc when the switching frequency is fs and the transmission frequency of the standard radio wave is fc, Interference can be reliably avoided.

According to the vehicle navigation device of the third aspect, the vehicle-mounted device according to the first or second aspect is provided. That is, since the navigation apparatus has a configuration corresponding to position acquisition means (for example, a GPS receiver) and position information storage means (map database), the in-vehicle apparatus of the present invention can be easily obtained by using them. Can be configured.

  Hereinafter, an embodiment in which the present invention is applied to a vehicle navigation apparatus will be described with reference to the drawings. FIG. 1 is a functional block diagram showing the electrical configuration of the entire car navigation device (vehicle device, hereinafter referred to as car navigation) 1. The car navigation system 1 includes a control unit (power source control unit) 2 mainly composed of a microcomputer (not shown) (not shown), a position specifying unit (position acquisition unit) 3, a memory unit 4, and a drive device (map database) 5 The display unit 6, the operation switch unit 7, the audio output unit 8, and the data communication unit 9 are connected. Each of these units operates using a DC voltage supplied from the switching power supply 10 as a drive source. And these parts and the switching power supply device 10 are built in the housing | casing which is not shown in figure, and the car navigation 1 is comprised.

  As is well known, the position specifying unit 3 includes a GPS sensor, a gyro sensor, a vehicle speed sensor, and the like (none of which are shown) used to obtain vehicle position information based on radio waves from GPS satellites. The current position, traveling direction, altitude, and the like are specified with high accuracy. It should be noted that it is not necessary to provide all of the above-described sensors depending on the specific accuracy required, and any one of them may be provided, and sensors other than those described above may be employed.

The memory unit 4 includes, for example, a ROM, a RAM, and an EEPROM (all of which are not shown). The ROM stores a control program for performing a normal navigation operation, and the RAM functions as a working area. The information such as map data acquired through the drive device 5 is temporarily stored, and the EEPROM stores predetermined data that needs to be retained even when the power is turned off.
The drive device 5 is configured to optically or magnetically read information recorded on an optical disk such as a DVD-ROM (not shown) or a hard disk. Examples of information recorded on the disc include various data such as map data, destination search data (destination data, so-called town page data, etc.) and synthetic voice data.

  The display unit 6 is configured by, for example, a full-color liquid crystal display, and a map around the current location of the vehicle is displayed on the screen at a selected scale while driving the vehicle, and is superimposed on the display. A current location mark indicating the current position and traveling direction of the vehicle is selectively displayed. The display unit 6 displays an input screen for the user to make various inputs such as a destination, and various messages. Further, when the route search to the destination and the route guidance function are executed, a route to be superimposed on the map, a mark indicating the destination, landmarks around the route, and the like are also displayed.

Although not shown, the operation switch unit 7 includes a mechanical switch provided near the screen of the display unit 6 and a touch panel provided on the screen of the display unit. A user (vehicle driver) can use the operation switch unit 7 to input various commands such as setting a destination for a route guidance operation and selecting a scale of a road map displayed on the display unit 6. It has become. A remote controller having the same function as the operation switch unit 7 may be provided as necessary.
The voice output unit 8 outputs a voice guide at the time of route guidance and a voice guide for operation explanation based on the synthesized voice data obtained through the drive device 5. The data communication unit 9 performs two-way communication via an external communication infrastructure (not shown), and is composed of, for example, a mobile phone, a car phone, or a beacon transceiver.

  When a power switch (not shown) provided in the operation switch unit 7 is pressed, the control unit 2 reads the control program stored in the ROM to initially start the car navigation system. By controlling, a location function for displaying the current position of the vehicle specified based on GPS or the like on the display unit 6 in a superimposed manner with a road map, and calculating and guiding a recommended route to the destination designated by the user Processing such as a route guidance function is performed.

  Further, FIG. 1 also shows a radio timepiece 30 disposed in, for example, a dashboard portion in the vehicle interior. As shown in FIG. 4, the radio clock 30 periodically receives standard radio waves transmitted by the Fukushima station located in Fukushima Prefecture and the Kyushu station located in Saga Prefecture in Japan, and is included in the radio signal. The time is corrected based on the current code. The radio timepiece 30 can receive in parallel a standard radio wave with a frequency of 40 kHz transmitted from the Fukushima station and a standard radio wave with a frequency of 60 kHz transmitted from the Kyushu station. Adopting the better one, it is configured to perform automatic channel selection.

  FIG. 2 is a diagram showing an electric circuit configuration of the switching power supply device 10 built in the car navigation system 1. A source of a p-channel FET (hereinafter referred to as an FET) 14 serving as a switching element has a predetermined DC power supply voltage from a battery power source or a power generation device (hereinafter simply referred to as a DC power source) 15 that generates power while the vehicle is running. Is supplied. A changeover switch (not shown) is provided between the power supply 15 and the source of the FET 14, and is turned on when the switching power supply device 10 is operated to supply power from the power supply 15 to the FET 14.

  The drain of the FET 14 is connected to one end of the coil 16a of the smoothing circuit 16 configured by connecting the coil 16a and the capacitor 16b in series, and one end of the capacitor 16b is grounded. A cathode of a flywheel diode 17 whose anode is grounded is connected between the drain of the FET 14 and the coil 16a. A DC voltage Va of a predetermined level is output from the common connection point 18 (smoothing circuit 16) of the coil 16a and the capacitor 16b, and the DC voltage Va is supplied to each electronic circuit board in the car navigation 1. It has become.

  The common connection point 18 is connected to one end of a resistor 19a of a voltage dividing circuit 19 configured by connecting two resistors 19a and 19b in series, and one end of the resistor 19b is grounded. In the voltage dividing circuit 19, the DC voltage Va is divided by the ratio of the resistance values of the resistors 19 a and 19 b, and the divided voltage (hereinafter referred to as a divided voltage) is output to the inverting input terminal of the error amplifier 20. The A reference voltage preset in order to determine the level of the DC voltage Va output from the smoothing circuit 16 is applied to the non-inverting input terminal of the error amplifier 20. Then, the error amplifier 20 calculates a difference between the reference voltage and the divided voltage, amplifies the difference value, and outputs it as a level adjustment signal. The amplitude of the level adjustment signal is set so as to be within the range of the amplitude of a triangular wave described later. The output terminal of the error amplifier 20 is connected to the non-inverting input terminal of the pulse width comparator 21.

  The triangular wave generation circuit 22 that is an oscillation circuit is configured by a phase-shift oscillation type that generates a triangular wave that is a carrier wave. The triangular wave generating circuit 22 is connected to a frequency control circuit 23 (described later) as a frequency control means and a capacitor 24, and has a time constant obtained by multiplying the resistance value of the frequency control circuit 23 as a set value and the capacitance of the capacitor 24. The triangular wave frequency is set in proportion to the reciprocal. Note that the capacitance of the capacitor 24 is fixed, and the frequency of the triangular wave is switched and set by the control unit 2 adjusting the resistance value of the frequency control circuit 23 as will be described later.

The triangular wave generated by the triangular wave generation circuit 22 is output to the inverting input terminal of the pulse width comparator 21. The pulse width comparator 21 compares the voltage of the level adjustment signal output from the error amplifier 20 (hereinafter referred to as a level adjustment voltage) with a triangular wave voltage (hereinafter referred to as a triangular wave voltage) to obtain a level adjustment voltage. When the voltage is larger than the triangular wave voltage, a high level is output, and in the opposite case, a low level is output. The signal output from the pulse width comparator 21 is applied to the gate of the FET 14 as a gate signal.
Each component described above is accommodated inside the apparatus main body, and thereby the switching power supply apparatus 10 is configured. A constant voltage source (not shown) that generates a constant DC voltage Vc from a power source is built in the apparatus main body, and each component operates with the DC power source Vc as a drive source.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing the contents of processing executed by the control unit 2 with respect to the part according to the gist of the present invention. When the control unit 2 acquires the current position of the vehicle from the position specifying unit 3 (step S1), the control unit 2 calculates the distance between the position and the Fukushima station and the Kyushu station, and determines which direction the current position is closer to. (Step S2).
Here, as shown in FIG. 4, the Fukushima station and the Kyushu station are located on the east and west sides of Japan, respectively, and both transmit standard radio waves with an output of 50 kW (effective radiation power of 10 kW). The radio waves can be received within an area having a radius of about 1000 km, and both of the receivable areas overlap. The map data read out by the drive device 5 of the car navigation 1 includes the positions of the Fukushima station (37 degrees 22 minutes N, 140 degrees 51 minutes E) and the Kyushu station (33 degrees 28 minutes N, 130 degrees 11 minutes E). Information is also stored. As described above, the transmission frequency of the Fukushima station is 40 kHz, and the transmission frequency of the Kyushu station is 60 kHz.

Reference is again made to FIG. In step S2, when the current position of the vehicle is close to the Fukushima station, the control unit 2 adjusts the resistance value of the frequency control circuit 23 and sets the switching frequency of the switching power supply device 10 to be, for example, 30 kHz (step S3). ). On the other hand, if the current position is close to the Kyushu station, the switching frequency is set to 35 kHz, for example (step S4).
That is, when the position of the vehicle is close to the Fukushima station, it is estimated that the radio timepiece 30 is highly likely to receive the standard radio wave transmitted by the Fukushima station. When the switching frequency is set to 30 kHz, the fundamental wave and its harmonic series are 30 kHz, 60 kHz, 90 kHz,..., So that they do not interfere with the standard radio wave transmission frequency of 40 kHz by the Fukushima station. . Therefore, interference with the reception of the standard radio wave by the radio timepiece 30 is avoided.

  On the other hand, when the position of the vehicle is close to the Kyushu station, it is estimated that the radio timepiece 30 is highly likely to receive the standard radio wave transmitted by the Kyushu station. When the switching frequency is set to 35 Hz, the fundamental wave and its harmonic series are 35 kHz, 70 kHz, 105 kHz,..., So that they do not interfere with the standard radio wave transmission frequency 60 kHz by the Kyushu station. . Accordingly, in this case as well, reception interference is avoided.

  As described above, according to the present embodiment, the switching power supply device 10 that generates and supplies power for operating the car navigation 1 is configured so that the switching frequency is variable, and the control unit 2 of the car navigation 1 The switching time of the switching power supply 10 is set so as to avoid occurrence of reception interference in the radio timepiece 30 depending on whether the radio timepiece 30 is capable of receiving a standard radio wave transmitted from any of a plurality of transmitting stations. Set to change. Specifically, the switching frequency is switched according to whether the position of the vehicle is closer to the Fukushima station or the Kyushu station. Therefore, even when the switching power supply device 10 is used, the radio timepiece 30 can receive the standard radio wave satisfactorily without being affected by the switching operation.

  Further, since the control unit 2 switches the switching frequency of the switching power supply device 10 so that the frequency and the harmonic series thereof do not match the transmission frequency of the standard radio wave, the reception generated by the switching operation of the switching power supply device 10 is performed. Interference can be reliably avoided. And since the car navigation 1 is provided with the position specific | specification part 3 and the drive apparatus 5, the vehicle-mounted apparatus of this invention can be easily comprised by using them.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications are possible.
Specific numerical values of the switching frequency may be any frequency that can avoid the occurrence of reception interference, it may be appropriately set according to individual design.
You may apply to other foreign countries, not limited to Japan. In that case, there may be three or more transmitting stations.
Not limited to car dual navigation system, the positional information can be acquired, it can be applied as long as the vehicle-mounted device using a switching power supply.

1 is a functional block diagram showing an electrical configuration of a car navigation device according to an embodiment when the present invention is applied to a vehicle navigation device. The figure which shows the electric circuit structure of a switching power supply device The flowchart which shows the processing content performed by the control part about the part which concerns on the summary of this invention Diagram showing the location of standard radio wave transmission stations in Japan

Explanation of symbols

  In the drawings, 1 is a car navigation device (on-vehicle device), 2 is a control unit (power supply control means), 3 is a position specifying unit (position acquisition means), 5 is a drive device (map database), 10 is a switching power supply device, 30 Indicates a radio clock.

Claims (3)

In an in-vehicle device configured to include a switching power supply device and a position acquisition unit that acquires a current position of the vehicle,
Position information storage means for storing the position information of a plurality of transmitting stations that transmit a standard radio wave received by a radio timepiece disposed in the passenger compartment,
The switching power supply device is configured such that a switching frequency is variable,
The switching power supply apparatus according to whether the position of the vehicle acquired by the position acquisition means is a position where the radio-controlled timepiece can satisfactorily receive a standard radio wave transmitted from any of the plurality of transmitting stations. Power switching means for switching and setting the switching frequency so as to avoid the occurrence of interference of the standard radio wave by the radio timepiece ,
The power supply control means switches and sets the switching frequency according to which of the plurality of transmitting stations is close to the position of the vehicle acquired by the position acquiring means. . The on-vehicle control device according to claim 1, wherein the power supply control means switches the switching frequency of the switching power supply device so that a fundamental wave and a harmonic series of the frequency do not coincide with a transmission frequency of the standard radio wave. apparatus. A vehicle navigation device comprising the on-vehicle device according to claim 1.

Images