JP2011198044A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device which can more efficiently reduce power consumption in accordance with an actual processing state.SOLUTION: A power supply part 4 can individually supply power to an operation circuit 8, a drawing circuit 9, a display circuit 10 and a video capture circuit 11 and to individually set power supply voltages supplied to respective circuits. A clock supply part 4 can individually supply clock signals to respective circuits and individually sets frequencies of clock signals supplied to respective circuits. In accordance with processing states of respective circuits 8 to 11 determined by control conditions given from the outside, a power-on/off control part 15 and a power supply voltage control part 16 control the power supply part 4 to stop the power supply to the respective circuits 8 to 11 or change the power supply voltages, and a frequency control part 17 controls the clock supply part 5 to change the frequencies of clock signals to the respective circuits 8 to 11.

Description

  The present invention relates to an electronic control device including one or more CPUs and a plurality of peripheral circuits controlled by the CPU.

  In general, low power consumption is always required for electronic devices. For example, Patent Document 1 discloses a technique for reducing power consumption by setting a control unit (CPU) in a sleep state during an on-vehicle device of a road-to-vehicle communication system except for a period in which road-to-vehicle communication is performed. Patent Document 2 discloses a technique for reducing power consumption of a CPU by changing a clock frequency according to the amount of data to be processed in an information processing apparatus such as an OA device.

JP 2000-259874 A JP-A-5-27867

However, in the above-described technology, when a trigger is given to wake up the control unit or increase the clock frequency, the operation clock is supplied to the peripheral circuit as well as the CPU or the clock frequency increases. Become. For this reason, there is a problem in that power consumption cannot be efficiently reduced because power consumption increases in circuit portions that do not require road-to-vehicle communication or circuit portions that do not require high-speed data processing.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electronic control device capable of more efficiently reducing power consumption according to actual processing conditions.

  According to the electronic control device of claim 1, the power supply circuit can individually supply power to the CPU and the plurality of peripheral circuits, and the power supply voltage supplied to each can be individually set. The clock circuit is configured to be able to individually supply a clock signal and to be able to individually set the frequency of the clock signal supplied to each. Then, according to the processing state of the CPU and / or peripheral circuit determined by the control condition given from the outside, the power supply control unit stops supplying power to the CPU and / or peripheral circuit or changes the power supply voltage. The clock control unit controls the clock circuit so as to change the frequency of the clock signal for the CPU and / or peripheral circuits.

  In other words, depending on the given control conditions, the CPU and a plurality of peripheral circuits that require high processing capability can be supplied at a high level by setting the power supply voltage at a high level or by setting the frequency of the supplied clock signal high. Can execute the process. For the CPU and the plurality of peripheral circuits that have no problem even if the processing capacity is reduced due to the above control conditions, power can be supplied by supplying the power supply voltage at a low level or setting the frequency of the supplied clock signal low. For those that can suppress consumption and do not require further processing, the power supply may be stopped. Therefore, according to the control condition given from the outside, the process to be executed can be executed at high speed, and the power consumption of the circuit portion (including the CPU) that does not require high processing capability can be suppressed.

  According to the second aspect of the present invention, when mounted on a vehicle, the control condition is a signal (vehicle signal) relating to the state of the vehicle. When the peripheral circuit is composed of an image processing circuit, a drawing circuit, and a display circuit, and a signal indicating “accessory ON” is given as a vehicle signal by operating the key cylinder switch, the power supply control unit The normal voltage power is supplied to the peripheral circuits other than the image processing circuit, and the clock control unit supplies the normal frequency clock signal to the peripheral circuits other than the CPU and the image processing circuit, and the image processing circuit has a low frequency. The clock signal is supplied.

  That is, when the power supply is turned on in the “accessory ON” state, it is necessary to display an initial screen on a display of a general in-vehicle device. Therefore, the CPU reads out the image data for displaying the initial screen from the storage device and outputs the image data to the drawing circuit. When the drawing data is rendered by the drawing circuit, the CPU displays the image data on the display device via the display circuit. Accordingly, a normal voltage power supply and a normal frequency clock signal are supplied to these so that the processing can be executed at high speed.

  Then, when a signal indicating the reverse of the vehicle is given as a vehicle signal from the “accessory ON” state, the image processing circuit converts the format of the image behind the vehicle captured by the camera, and displays it on the display device via the display circuit. It is necessary to realize a so-called back guide monitor function. Therefore, the power control unit allows the image processing circuit to supply the normal voltage power, and the clock control unit allows the image processing circuit to supply the normal frequency clock signal so that the image processing circuit can execute format conversion processing at high speed. Put it in a state. Further, the power supply control unit lowers the power supply voltage supplied to the CPU and the drawing circuit that do not need to perform high-speed processing in this case. Therefore, when the electronic control device is mounted on a vehicle and performs a back guide monitor function, necessary processing can be performed at high speed and unnecessary power consumption can be suppressed.

According to the third aspect of the present invention, when the electronic control device is mounted on the vehicle as in the second aspect and the configuration of the peripheral circuit is the same as that in the second aspect, the state of the vehicle given as the vehicle signal is “parking”. Then, the power control unit supplies the normal voltage power to all of the CPU and peripheral circuits, and the clock control unit supplies the normal frequency clock signal to all of the above.
For example, when the vehicle shift position becomes “parking” and becomes “parking”, the vehicle state restarts from there, or the engine is stopped and the accessory is further turned “off”. It is also envisaged that the system will be completely stopped. Therefore, in the case of “parking”, all the CPU and peripheral circuits are supplied with normal voltage power and a normal frequency clock signal so as to be able to quickly respond to any change in the state of the vehicle from there. To supply.

  Then, when the “parking” state is released and a speed signal indicating that the vehicle has started running is given, the power supply control unit stops power supply to the image processing circuit. That is, when the vehicle starts to travel, there is no opportunity to execute the back guide monitor function using the camera, so that power consumption can be suppressed by stopping the power supply to the image processing circuit.

  According to the electronic control device of the fourth aspect, the functions of the power control unit and the clock control unit are mounted on the CPU. In other words, if external control conditions are given to the CPU, the CPU can control the power supply circuit and the clock supply circuit, so that the functions of the power supply control unit and the clock control unit can be achieved. Therefore, it is not necessary to provide separate CPUs for the functions of the power supply control unit and the clock control unit, and the electronic control device can be configured at low cost.

  According to the electronic control device of the fifth aspect, the power control unit and the clock control unit are configured by one CPU separate from the CPU. That is, if one external control condition is given to the CPU and the CPU controls the power supply circuit and the clock supply circuit, the functions of the two control circuits can be shared.

The block diagram which is 1st Example and shows the structure of a car navigation system Flow chart showing mainly the contents of control by power supply / frequency control unit Timing chart showing changes in power supply and frequency FIG. 2 equivalent view showing the second embodiment 3 equivalent figure FIG. 1 equivalent view showing the third embodiment FIG. 1 equivalent view showing the fourth embodiment

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a car navigation system. The car navigation system (electronic control device) 1 includes a navigation circuit 2, a map data storage unit 3, a power supply unit (power supply circuit) 4, a clock supply unit (clock circuit) 5, a vehicle I / F unit 6, an LCD (Liquid Crystal Display) ) 7 etc.

  The navigation circuit 2 is configured around an arithmetic circuit (CPU, microcomputer) 8. When the map data is read out from the map data storage unit 3 including a storage device such as a hard disk, the navigation circuit 2 passes through a drawing circuit (peripheral circuit) 9. Image display data is given to the display circuit (peripheral circuit) 10 and a map image or the like is displayed on the LCD (display device) 7. The drawing circuit 9 corresponds to, for example, a graphic processor, and the display circuit 10 corresponds to an LCD controller. In addition, about the receiving part etc. which receive the GPS signal which a GPS (Global Positioning System) satellite transmits, illustration is abbreviate | omitted.

  Further, the navigation circuit 2 includes a video capture circuit (peripheral circuit, image processing circuit) 11. The video capture circuit 11 converts image data in the NTSC format output from a rear camera (for example, comprising a CCD (Charge Coupled Device) or a CMOS image sensor) 12 that captures an image on the rear side of the vehicle body 13 into RGB data. It is written and stored in a V (video) RAM (not shown). Then, the image data stored in the VRAM is directly output to the display circuit 10 to display the image data on the LCD 7. Further, although not shown, the video capture circuit 11 relays the data received by the in-vehicle television and the data reproduced by the DVD player and outputs the data to the LCD 7.

  The navigation circuit 2 includes an I / O port 14. The I / O port 14 transmits vehicle signals (for example, accessories, reverse, diagnostics, parking, ignition, speed pulses, etc.) transmitted from the vehicle body 13 side by in-vehicle communication such as CAN via the vehicle I / F unit 6. Are received and output to the arithmetic circuit 8.

The power supply unit 4 is a power supply circuit that supplies power to each unit of the car navigation system 1, and includes a power supply ON / OFF control unit (power supply control unit) 15 and a power supply voltage control unit (power supply control) that realize the function by a microcomputer. Part) 16, and these can also receive vehicle signals via the vehicle I / F part 6. The power supply unit 4 supplies power to the arithmetic circuit 8, the drawing circuit 9, the display circuit 10, and the video capture circuit 11 independently, and each power supply is supplied by the function of the power supply ON / OFF control unit 15. Individual ON / OFF control is possible.

  Further, each power supply voltage can be individually controlled by the function of the power supply voltage control unit 16. For example, when the power supply circuit is composed of a series regulator or the like, the voltage is controlled by changing the voltage dividing ratio of the resistor so as to change the reference voltage applied to the operational amplifier that controls the step-down transistor.

  The clock supply unit 5 is configured to supply clock signals to the arithmetic circuit 8, the drawing circuit 9, the display circuit 10, and the video capture circuit 11 independently (but in synchronization with each other) (clock). (1) to (4)). In addition, a circuit configuration for individually dividing or multiplying each clock signal is provided, and the frequency of the clock signal can be individually controlled. The function of the frequency control unit (clock control unit) 17 is realized by a microcomputer and can receive a vehicle signal via the vehicle I / F unit 6. Then, the frequency of the clock signal supplied independently is controlled by the function of the frequency control unit 17.

  The power supply ON / OFF control unit 15, the power supply voltage control unit 16, and the frequency control unit 17 are always supplied with the operation power generated from the vehicle battery + B and have a relatively low frequency clock. A signal is being supplied. Therefore, these control units 15 to 17 are always operating while being mounted on the vehicle.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing mainly the contents of control by the power ON / OFF control unit 15, the power supply voltage control unit 16, and the frequency control unit 17. First, when the key cylinder switch is operated by the driver on the vehicle body 13 side and “accessory (ACC) ON” is given as a vehicle signal (step S1: YES), reverse “reverse (REV)” is further inputted as a vehicle signal. It is determined whether or not it has been done (step S2).
If the vehicle signal “reverse” is not input in step S2 (NO), the power ON / OFF control unit 15 and the power supply voltage control unit 16 turn off the video capture circuit 11 and all other circuits 8. The power supplies 10 to 10 are turned on and the power supply voltage is supplied at a level (high) (step S7). Further, the frequency control unit 17 sets the frequency of the clock signal supplied to all the circuits 8 to 11 to (high) (step S8).

  That is, when the vehicle does not move backward, it is not necessary to display the image data picked up by the rear camera 12 on the LCD 7, so that the video capture circuit 11 is not operated. Accordingly, the video capture circuit 11 is turned off. In this case, the car navigation system 1 needs to display an initial screen after power-on on the LCD 7 and then display a map image corresponding to the current position. Therefore, power is supplied to the arithmetic circuit 8, the drawing circuit 9, and the display circuit 10 at a voltage level (high) (see FIG. 3: Phase (A)). When the arithmetic circuit 8 reads the initial screen data read from a memory (storage device) (not shown), the arithmetic circuit 8 gives the image data to the drawing circuit 9 and displays it on the LCD 7 via the display circuit 10. Then, when the map image data corresponding to the current position read from the map data storage unit 3 is read, it is displayed in the same manner.

  After execution of step S8, the process proceeds to step S5, where it is determined whether or not the vehicle signal “accessory ON” is continuously given (YES), and the process returns to step S2.

  On the other hand, when the vehicle signal “reverse” is given in step S2 (YES), the power supply ON / OFF control unit 15 and the power supply voltage control unit 16 also turn on the video capture circuit 11 (step S3). As a result, all the circuits are turned on. Then, the level of the power supply voltage supplied to the video capture circuit 11 is set to (high), and the voltage level supplied to the arithmetic circuit 8 and the drawing circuit 9 is switched to (low) (step S3). Then, the frequency of the clock signal supplied to the arithmetic circuit 8 and the drawing circuit 9 is switched to (low) (step S4).

  That is, when the vehicle moves backward, it is necessary to display an image captured by the rear camera 12 on the LCD 7 to realize a back guide monitor function. Therefore, the power supply of the video capture circuit 11 is turned on and the power supply voltage level is supplied at (high) to operate at high speed at the frequency (high) of the clock signal. In this case, since the image data is supplied to the LCD 7 directly from the video capture circuit 11 to the display circuit 10, the arithmetic circuit 8 and the drawing circuit 9 do not need to be operated at high speed. Therefore, the level of the power supply voltage supplied to these is set to (low), and the frequency of the clock signal is also set to (low). After execution of step S4, the process proceeds to step S5 (see FIG. 3: Phase (B)).

  If the vehicle signal “reverse” is not given from the above state, “NO” is determined in step S2, and steps S7 and S8 are executed. In this case, what is displayed on the LCD 7 is still a map image (see FIG. 3: Phase (C)). Then, when the vehicle signal “accessory ON” is not given (step S5: NO), the power supply ON / OFF control unit 15 turns off the power supply of all circuits, and the power supply voltage control unit 16 sets the power supply voltage level of all circuits. The frequency control unit 17 sets the frequency of the clock signal supplied to all the circuits to (low) (see step S6, phase (D) in FIG. 3). Moreover, after execution of step S6, you may make it return to step S1.

  The setting of the power supply voltage level (high) and (low) and the setting of the clock signal frequency (high) and (low) vary depending on individual circuit specifications, etc. (Normal) If the power supply voltage is about 1.2V, it is set to level (high), and 1.1V is set to level (low). If the stationary clock signal frequency is about 500 MHz, it is set to (high) and the frequency 250 MHz is set to (low).

  As described above, according to this embodiment, the power supply unit 4 of the car navigation system 1 can individually supply power to the arithmetic circuit 8, the drawing circuit 9, the display circuit 10, and the video capture circuit 11. The power supply voltage to be supplied to can be set individually. Further, the clock supply unit 4 is configured to be able to individually supply a clock signal and to be able to individually set the frequency of the clock signal supplied to each.

  Then, according to the processing state of the arithmetic circuit 8, the drawing circuit 9, the display circuit 10, and the video capture circuit 11 determined by control conditions given from the outside, the power ON / OFF control unit 15 and the power supply voltage control unit 16 The power supply unit 4 is controlled to stop the supply of power to the circuits 8 to 11 or to change the power supply voltage, and the frequency control unit 17 changes the frequency of the clock signal to the circuits 8 to 11. The clock supply unit 5 is controlled. Therefore, according to the control condition given from the outside, the process to be executed can be executed at high speed, and the power consumption of the circuit portion that does not require high processing capability can be suppressed.

  Specifically, when the vehicle signal “accessory ON” is given from the vehicle main body 13 side, the power ON / OFF control unit 15 applies the normal voltage to the peripheral circuits 9 to 10 excluding the arithmetic circuit 8 and the video capture circuit 11. The power is supplied, and the frequency control unit 17 supplies the normal frequency clock signal to the peripheral circuits 9 to 10 excluding the arithmetic circuit 8 and the video capture circuit 11 and supplies the low frequency clock signal to the video capture circuit. Let That is, when “accessory ON” is selected, the arithmetic circuit 8 reads out the image data for displaying the initial screen from the memory and outputs the image data to the drawing circuit 9. When the drawing circuit 9 performs the drawing process, The image is displayed on the LCD 7 via the circuit 10. Accordingly, a normal voltage power supply and a normal frequency clock signal are supplied to these, so that the processing is executed at high speed.

  When the vehicle signal “reverse” is given, the video capture circuit 11 converts the format of the image data of the rear of the vehicle captured by the rear camera 12 and displays it on the LCD 7 via the display circuit 10 to perform the back guide monitor function. To achieve this, the power supply voltage control unit 16 causes the video capture circuit 11 to supply a normal voltage power supply, and the frequency control unit 17 causes the video capture circuit 11 to supply a normal frequency clock signal. Further, the power supply voltage control unit 16 reduces the power supply voltage supplied to the arithmetic circuit 8 and the drawing circuit 9 that do not need to perform processing at high speed in this case. Therefore, necessary processing can be performed at high speed and unnecessary power consumption can be suppressed.

(Second embodiment)
4 and 5 show a second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Hereinafter, different parts will be described. The configuration of the second embodiment is the same as that of the first embodiment, and shows an example in which the given vehicle signals are different. 4 and 5 correspond to FIGS. 2 and 3, respectively. In FIG. 4, if “YES” is determined in step S1 as in the first embodiment, “speed pulse (speed signal)” is input as a vehicle signal (step S11) or “parking (parking)” is input. It is determined whether it has been done (step S12).

  If “speed pulse” is not input (step S11: NO) and “parking” is input (step S12: YES), the vehicle is in a stopped state, and the state is shifted to any state from here. Can do. Therefore, the power ON / OFF control unit 15 turns on the power of all the circuits, and the power supply voltage control unit 16 sets the level of the power supply voltage supplied to all the circuits to (high) (step S13). The frequency control unit 17 sets the frequency of the clock signal supplied to all the circuits to (high) (see step S14, phase (D) in FIG. 5). By setting in this way, when the state of the vehicle subsequently changes, processing to be performed correspondingly can be quickly executed.

When the input of the vehicle signal “speed pulse” is started from the above state (step S11: YES), the power ON / OFF control unit 15 turns only the power source of the video capture circuit 11 to OF (step S15). Moreover, the frequency control part 17 is made into the state similar to the setting in step S14 (refer step S16 and FIG. 5 phase (B)). That is, in this case, it means that the vehicle has started running, so it is not necessary to display an image captured by the rear camera 12, and display of a playback image of a TV or DVD player should be prohibited for safety. Therefore, there is no opportunity to operate the video capture circuit 11.
Even when the vehicle signal “parking” is not given prior to the start of input of the speed pulse (step S12: NO), there is a very high probability that the vehicle will start traveling, so the process proceeds to step S15 as described above. .

  As described above, according to the second embodiment, when the vehicle signal “parking” is given, the power ON / OFF control unit 15 supplies all of the arithmetic circuit 8 and the peripheral circuits 9 to 11 with normal voltage power, The frequency control unit 17 causes all the circuits 8 to 11 to supply a clock signal having a normal frequency. When the vehicle signal “parking” is no longer given and a speed pulse indicating that the vehicle has started running is given, the power ON / OFF control unit 15 stops the power supply to the video capture circuit 11. Therefore, power consumption can be suppressed by stopping power supply to the video capture circuit 11 that is not used when the vehicle starts running.

(Third embodiment)
FIG. 6 shows a third embodiment, and the differences from the first embodiment will be described. In FIG. 6 corresponding to FIG. 1, a car navigation system (electronic control device) 21 is replaced with a power supply unit 4 and a clock supply unit 5, a power supply circuit 22, a clock supply circuit (clock circuit) 23, a power supply / frequency control. The unit 24 is provided. The power supply circuit 22 and the clock supply circuit 23 are configured only by hardware excluding the power ON / OFF control unit 15, the power supply voltage control unit 16, and the frequency control unit 17 from the power supply unit 4 and the clock supply unit 5. The power / frequency control unit 24 is configured by a microcomputer (CPU) that controls the functions of the control units 15 to 17.

  Accordingly, the vehicle signals are collectively supplied to the power / frequency control unit 24, and the power / frequency control unit 24 provides control signals to the power supply circuit 22 and the clock supply circuit 23 to turn on / off the power supply for each circuit. Performs OFF control, power supply voltage control, and clock signal frequency control. In the case of the third embodiment configured as described above, the same effect as that of the first embodiment can be obtained.

(Fourth embodiment)
FIG. 7 shows the fourth embodiment, and the differences from the third embodiment will be described. The car navigation system (electronic control device) 31 of the third embodiment is a case where the arithmetic circuit 33 has the function of the power / frequency control unit 24 in the third embodiment. That is, the arithmetic circuit 33 has a built-in power / frequency control function unit (power control unit, frequency control unit) 34. The arithmetic circuit 33 gives control signals to the power supply circuit 22 and the clock supply circuit 23, and each circuit Power supply ON / OFF control, power supply voltage control, and clock signal frequency control. In the case of the fourth embodiment configured as described above, the same effect as that of the first embodiment can be obtained. Further, the arithmetic circuit 33 also controls the power supply and the clock signal, so that it can be configured at a lower cost than the car navigation system 31.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications or expansions are possible.
The first and second embodiments may be executed in combination. In this case, if “YES” is determined in step S11 or “NO” is determined in step S12, the determination in step S2 may be performed.
Two or more CPUs may be mounted on the navigation circuit 2.
What functions to select for each peripheral circuit may be determined according to the individual design.
The rear camera 12 may be provided as necessary.
In the first embodiment, the power ON / OFF controller 15 and the power voltage controller 16 may be configured as one power controller.

What voltage to set each of the normal voltage of the power supply and the voltage to be reduced, and what frequency to set the normal frequency of the clock signal and the frequency to be reduced, respectively, can be appropriately changed according to the individual design. good.
The display is not limited to the LCD 7, but may be an EL (Electro Luminescence) display or the like.
The present invention is not limited to an on-vehicle electronic control device, and can be applied as long as it includes one or more CPUs and a plurality of peripheral circuits.

  In the drawings, 1 is a car navigation system (electronic control unit), 4 is a power supply unit (power supply circuit), 5 is a clock supply unit (clock circuit), 7 is an LCD (display), 8 is an arithmetic circuit (CPU), 9 Is a drawing circuit (peripheral circuit), 10 is a display circuit (peripheral circuit), 11 is a video capture circuit (peripheral circuit, image processing circuit), 12 is a rear camera, 15 is a power ON / OFF controller (power controller), 16 is a power supply voltage control unit (power supply control unit), 17 is a frequency control unit (clock control unit), 21 is a car navigation system (electronic control unit), 22 is a power supply circuit, 23 is a clock supply circuit (clock circuit), 24 Is a power / frequency control unit, 31 is a car navigation system (electronic control device), 33 is an arithmetic circuit (CPU, power / frequency control unit), and 34 is a power / frequency control function unit (electric power control unit). Control unit, showing the frequency control unit).

Claims (5)

One or more CPUs;
A plurality of peripheral circuits controlled by the CPU;
A power supply circuit configured to be able to individually supply power to the CPU and the plurality of peripheral circuits, and to be able to individually set a power supply voltage supplied to each of the CPU and the plurality of peripheral circuits;
The supply of power to the CPU and / or the peripheral circuit is stopped or the power supply voltage is changed according to the processing state of the CPU and / or the peripheral circuit determined by control conditions given from the outside. A clock configured to be able to individually supply a clock signal to the power supply control unit that controls the power supply circuit, the CPU and the plurality of peripheral circuits, and to be able to individually set the frequency of the clock signal supplied to each Circuit,
A clock for controlling the clock circuit so as to change the frequency of the clock signal for the CPU and / or the peripheral circuit according to the processing state of the CPU and / or the peripheral circuit determined by a control condition given from the outside. An electronic control device comprising a control unit. Mounted on a vehicle, the control condition is a signal relating to the state of the vehicle;
The peripheral circuit is
An image processing circuit for converting the format of image data output from a camera that captures a rear image of the vehicle and storing the image data in an image memory;
A drawing circuit for drawing the image data given through the CPU;
A display circuit configured to output and display image data output from the image processing circuit or the drawing circuit on a display;
When the key cylinder switch is operated and "Accessory ON" is set,
The power control unit supplies power of a normal voltage to the CPU and peripheral circuits excluding the image processing circuit,
The clock control unit supplies a clock signal having a normal frequency to the CPU and peripheral circuits other than the image processing circuit, and supplies a clock signal having a low frequency to the image processing circuit.
When a signal indicating reverse travel of the vehicle is given in the state of the “accessory ON”,
The power supply control unit supplies the image processing circuit with a normal voltage power supply and reduces the power supply voltage supplied to the CPU and the drawing circuit.
The electronic control apparatus according to claim 1, wherein the clock control unit causes the image processing circuit to supply a clock signal having a normal frequency. Mounted on a vehicle, the control condition is a signal relating to the state of the vehicle;
The peripheral circuit is
An image processing circuit for converting the format of image data output from a camera that captures a rear image of the vehicle and storing the image data in an image memory;
A drawing circuit for drawing the image data given through the CPU;
A display circuit for displaying image data output from the image processing circuit or the drawing circuit;
When the state of the vehicle is “parking”,
The power control unit supplies normal voltage power to all of the CPU and the peripheral circuit,
The clock control unit supplies a clock signal having a normal frequency to all of the CPU and the peripheral circuit,
The power supply control unit stops power supply to the image processing circuit when a speed signal indicating that the vehicle has started running is released after the parking state is released. 3. The electronic control device according to 1 or 2.   4. The electronic control device according to claim 1, wherein functions of the power control unit and the clock control unit are mounted on the CPU.   4. The electronic control device according to claim 1, wherein the power control unit and the clock control unit are configured by a single CPU that is separate from the CPU.

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