JP2009240017A - Power supply device and door unlock system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to detect the state of charge of a power storing means without routing a wire from the power storing means to a power supply device that supplies power to a power consuming device having the power storing means such as a battery and a capacitor. <P>SOLUTION: In a smart entry system, a smart ECU repeatedly supplies power to an in-vehicle receiver having a backup capacitor only for a predetermined supply period per unit time (S110). At least one of monitored power, voltage, and current is compared with a preset threshold value (S120). Based on the magnitude relation between them, it is determined whether or not it is required to charge the backup capacitor. In the smart ECU, therefore, the state of charge of the backup capacitor can be detected without routing a wire for detecting the state of charge of the backup capacitor between it and the in-vehicle receiver. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply device for supplying power to a power consuming device having power storage means such as a battery, and a door lock release system including the power supply device.

Conventionally, the power supply that monitors the state of charge (voltage) of the battery, increases the power supplied from the generator if the battery is not charged, and decreases the power supplied from the generator if the battery is charged The device is known.
Japanese Patent Laid-Open No. 58-043146

  However, the device described in Patent Document 1 requires wiring for detecting the battery potential. In particular, when the power supply device is configured to charge the battery via the power consumption device having a battery, the wiring from the battery to the power supply device becomes very long, or the connector is used for this wiring. There is a problem that the number of terminals needs to be increased. Further, as the number of wirings increases, the weight increases and the cost increases.

  Therefore, in view of such problems, in a power supply device that supplies power to a power consuming device having a power storage means such as a battery or a capacitor, the state of charge of the power storage means can be changed without routing wiring from the power storage means to the power supply device. It is an object of the present invention to enable detection.

  2. The power supply device according to claim 1, wherein the power supply means repeatedly supplies power for a predetermined supply time per unit time to the power consuming device having the power storage means. . The charging determination unit compares the power, voltage, or current monitored by the monitoring unit with a preset threshold value, and determines whether or not the storage unit needs to be charged according to the magnitude relationship. Determine.

  According to such a power supply device, it is possible to detect the state of charge of the power storage unit without routing the charge state detection wiring of the power storage unit with the power consuming device. Therefore, it is possible to reduce the weight and cost by the amount of the charge state detection wiring.

  By the way, in the power supply device according to claim 1, when it is determined by the charge determination means that the power storage means needs to be charged, the power supply apparatus according to claim 2 Supply time increase changing means for increasing the supply time may be provided.

According to such a power supply device, more power can be supplied when the power consuming device charges the power storage means, so that the charging time of the power storage means can be shortened.
Further, in the power supply apparatus according to claim 2, as described in claim 3, after the operation of the supply time increase changing means, it is determined by the charge determination means that charging of the power storage means is unnecessary. And a supply time decrease changing means for reducing the supply time per unit time by the power supply means.

According to such a power supply device, since the power supplied by the power supply device can be reduced when the charging of the power storage unit is completed, the power supply device can save power.
Next, the door lock release system according to claim 4 is configured by a receiving device and a control device, and the receiving device is configured as the power consuming device according to any one of claims 1 to 3. The control device is configured as a power supply device according to any one of claims 1 to 3.

  According to such a door lock release system, at least the same effects as those described in claim 1 can be obtained. Further, when the engine in the vehicle is turned off (that is, when the generator is not driven), the power consumption of the receiving device can be suppressed, so that the battery in the vehicle can be prevented from being insufficiently charged. it can.

Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a smart entry system 1 to which the present invention is applied.
The smart entry system 1 is a system that unlocks a door by communication between a smart key 22 possessed by an occupant and a vehicle side device (smart ECU 10 (power supply device) and in-vehicle receiver 30 (power consumption device)). Specifically, as shown in Fig. 1, the smart entry system 1 performs communication with the smart key 10 that receives power from the in-vehicle battery 21 and the smart key 22 that receives power from the smart ECU 10. And an in-vehicle receiver 30.

  The smart ECU 10 is configured as a well-known electronic control device including a CPU, a ROM, a RAM, and the like (not shown). In addition, the smart ECU 10 includes a signal processing circuit 11, a power determination circuit 12, a power control circuit 13, and a power circuit. 14 (power supply means). The in-vehicle receiver 30 includes a receiving circuit 31 including a memory 32, a backup capacitor 33 (power storage unit), and a receiving antenna 34.

  Here, when the occupant gets into the vehicle, the reception circuit 31 receives the signal from the smart key 22 possessed by the occupant via the reception antenna of the in-vehicle receiver 30, and the reception circuit 31 demodulates the signal. Then, the receiving circuit 31 sends the data obtained by demodulation to the signal processing circuit of the smart ECU 10.

  Then, the signal processing circuit 11 extracts the ID of the smart key 22 (information for identifying the key) from the data received from the receiving circuit 31. Subsequently, the CPU of the smart ECU 10 authenticates the smart key 22 by comparing the extracted ID with the ID written in the ROM or RAM, and this authentication is established, and the unlock button in the smart key 22 is established. Is pushed or the occupant is detected by the door sensor 23, the door is unlocked via the vehicle control circuit 24.

  By the way, the power supply control circuit 13 of the smart ECU 10 normally transmits a command to supply power to the power supply circuit 14 intermittently. Then, the power supply circuit 14 intermittently outputs a predetermined voltage (for example, 5 V) to the receiving circuit 31 of the in-vehicle receiver 30.

  Here, the receiving circuit 31 of the in-vehicle receiver 30 includes a memory 32 for storing information (specifically, for example, setting parameters) necessary for the operation of the receiving circuit 31. The recorded content in the memory 32 is held by the power from the backup capacitor 33.

  In such a configuration, the CPU of the smart ECU 10 performs control to supply power intermittently or continuously from the power supply circuit 14 to the receiving circuit 31. The processing at this time will be described with reference to FIG. FIG. 2 is a flowchart showing power supply control processing executed by the CPU of the smart ECU 10. The power supply control circuit 12 and the power supply control circuit 13 may have a power supply control process function.

  This power supply control process is started when the smart entry system 1 is activated. First, a command is transmitted to the power supply control circuit 13 to intermittently supply power from the power supply circuit 14 (S110: decrease in supply time) Change means). Then, the power supply control circuit 13 intermittently supplies power to the power supply circuit 14.

  Subsequently, the output voltage V (see FIG. 1) of the power supply circuit 14 is detected using the power supply determination circuit 12, and it is determined whether or not the output voltage V is equal to or higher than a predetermined determination voltage Vsh (S120). : Monitoring means, charging determination means). If the output voltage V is equal to or higher than the determination voltage Vsh (S120: YES), the process returns to S110.

  If the output voltage V is less than the determination voltage Vsh (S120: NO), a command is transmitted to the power supply control circuit 13 to continuously supply power from the power supply circuit 14 (S130: supply time increase changing means). Then, the power control circuit 13 continuously supplies power to the power circuit 14.

  In the process of S120, the process of comparing the output voltage V and the determination voltage Vsh is performed at a predetermined timing (a timing at which the output voltage V is increased. Specifically, at each predetermined period (for example, 250 ms). When the power supply circuit 14 supplies power for 100 ms in each cycle, the power supply circuit 14 may be implemented after 80 ms from the start of power supply. However, the output voltage V may be an average value of voltages when the power supply circuit 14 supplies power.

  In the present embodiment, the power supply control process as described above is performed because the power required by the receiving circuit 31 varies greatly depending on the state of charge of the backup capacitor 33, and accordingly, the output of the power supply circuit 14. This is because the voltage V also changes. Specifically, this will be described with reference to FIG.

  3A is a graph showing the output voltage from the power supply circuit 14, FIG. 3B is a graph showing the internal potential of the receiving circuit 31 when the backup capacitor 33 is relatively charged, and FIG. 3C. These are graphs showing the internal potential of the receiving circuit 31 when the backup capacitor 33 is not charged.

  When receiving a command to supply power intermittently from the power supply control circuit 13, the power supply circuit 14 tries to supply a rectangular wave having a predetermined duty ratio (see the broken line in FIG. 3A). Here, the actual output voltage V from the power supply circuit 14 depends on the amount of power consumed by the receiving circuit 31, and when the backup capacitor 33 is sufficiently charged, it becomes a substantially rectangular wave, and the output voltage V is determined. The voltage rises to the voltage Vsh or higher (see the solid line (1) in FIG. 3A).

  At this time, as shown in FIG. 3B, the internal potential of the receiving circuit 31 is a potential at which the receiving circuit 31 can be activated each time power is supplied from the power supply circuit 14 (startable voltage Vl). ) Will be exceeded.

  Note that the receiving circuit 31 is configured so that once activated, the activated state can be maintained even if the supplied voltage falls below the activatable voltage Vl. In addition, the reception circuit can receive the radio wave from the smart key 22 when the startable voltage Vl is exceeded, and the transmission timing of the radio wave by the smart key 22 and the period in which the power is supplied by the power supply circuit 14. And have been adjusted.

  Next, in a state where the backup capacitor 33 is hardly charged, most of the power supplied to the reception circuit 31 is consumed to charge the backup capacitor 33, and the reception circuit 31 requires a large amount of power. To do. At this time, since a large current flows from the power supply circuit 14 to the receiving circuit 31 as compared with the state in which the backup capacitor 33 is sufficiently charged, the output voltage V decreases.

  That is, the output voltage V in a state in which the backup capacitor 33 is hardly charged does not increase so much and becomes a value less than the determination voltage Vsh (see the solid line (2) in FIG. 3A).

  At this time, as shown by the solid line in FIG. 3C, the potential inside the receiving circuit 31 gradually increases every time power is supplied from the power supply circuit 14, but the receiving circuit 31 is activated. It takes a considerable time to exceed the potential (startable voltage Vl) that can be generated.

  Therefore, in the above power supply control process, it is determined whether or not the power supply voltage V is equal to or higher than the determination voltage Vsh at a predetermined determination timing (the timing described as “determination” in FIG. 3A). Is less than the determination voltage Vsh, it is determined that the backup capacitor 33 needs to be charged, and the power supply method from the power supply circuit 14 is switched from intermittent power supply to continuous power supply. As described above, when the power supply method from the power supply circuit 14 is switched to the continuous power supply, the potential inside the reception circuit 31 quickly exceeds the startable potential as shown by the broken line in FIG.

  In the smart entry system 1 described in detail above, the identification data is received by receiving radio waves from the vehicle smart key 22 for transmitting radio waves including unique identification data (ID) and demodulating the radio waves. It is determined whether the in-vehicle receiver 30 to be extracted and the identification data extracted by the in-vehicle receiver 30 match the identification data recorded in advance in advance. Smart ECU 10 for releasing the lock. The smart ECU 10 repeatedly supplies power for a predetermined supply time per unit time to the in-vehicle receiver 30 having the backup capacitor 33 using the power supply circuit 14 in the power supply control process.

  According to such a smart ECU 10, since the power consumption of the in-vehicle receiver 30 can be suppressed when the engine in the vehicle is off (that is, when the generator is not driven), the battery in the vehicle is charged. It is possible to prevent a shortage.

  In addition, the smart ECU 10 compares at least one of monitored power, voltage, and current with a preset threshold value, and whether the backup capacitor 33 needs to be charged according to the magnitude relationship. Determine whether or not.

  Therefore, according to such smart ECU 10, it is possible to detect the charging state of the backup capacitor 33 without routing the wiring for detecting the charging state of the backup capacitor 33 with the in-vehicle receiver 30. Therefore, it is possible to reduce the weight and cost by the amount of the charge state detection wiring.

Further, when it is determined that the backup capacitor 33 needs to be charged, the smart ECU 10 increases the supply time per unit time.
According to such smart ECU 10, since the on-vehicle receiver 30 can supply more power when charging the backup capacitor 33, the charging time of the backup capacitor 33 can be shortened.

  Further, after increasing the supply time per unit time, the smart ECU 10 decreases the supply time per unit time if it is determined that charging of the backup capacitor 33 is unnecessary.

  According to such a smart ECU 10, the electric power supplied by the smart ECU 10 can be reduced when the charging of the backup capacitor 33 is completed, so that the smart ECU 10 can save power.

The embodiment of the present invention is not limited to the above-described embodiment, and can take various forms as long as it belongs to the technical scope of the present invention.
For example, in the above embodiment, the power supply circuit 14 is configured to detect the potential (voltage) in the wiring for supplying power to the receiving circuit 31 in order to detect the charging state of the backup capacitor 33. Not only the potential but also current and power may be detected. In such a case, if the current or power is equal to or greater than a predetermined threshold, it may be determined that the backup capacitor 33 needs to be charged.

  Each threshold used for the determination is experimentally obtained from the relationship between the potential of the backup capacitor 33 and the potential, current, or power in the wiring for supplying power, and is set based on these relationships. It only has to be.

1 is a block diagram showing a schematic configuration of a smart entry system 1. FIG. It is a flowchart which shows an electric power feeding control process. A graph (a) showing the output voltage from the power supply circuit 14, a graph (b) showing the potential inside the receiving circuit 31 when the backup capacitor 33 is relatively charged, and a state where the backup capacitor 33 is not charged. 6 is a graph (c) showing an internal potential of the receiving circuit 31.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Smart entry system, 10 ... Smart ECU, 11 ... Signal processing circuit, 12 ... Power supply determination circuit, 13 ... Power supply control circuit, 14 ... Power supply circuit, 21 ... In-vehicle battery, 22 ... Smart key, 23 ... Door sensor, 24 ... Vehicle control circuit, 30 ... vehicle-mounted receiver, 31 ... receiving circuit, 32 ... memory, 33 ... backup capacitor, 34 ... receiving antenna.

Claims (4)

A power supply device that supplies power to a power consuming device that consumes more power than charging the power storage means when charging the power storage means that it has,
Power supply means for repeatedly supplying power to the power consuming device for a predetermined supply time per unit time;
Monitoring means for monitoring power, voltage, or current when the power supply means supplies power;
The power storage means when the power monitored by the monitoring means is less than the reference power, when the voltage monitored by the monitoring means is less than the reference voltage, or when the current monitored by the monitoring means is greater than or equal to the reference current Charging determination means for determining that charging is necessary,
A power supply device comprising: A supply time increase changing means for increasing a supply time per unit time by the power supply means when the charge determination means determines that the power storage means needs to be charged. Item 2. The power supply device according to Item 1. After the operation of the supply time increase change means, if the charge determination means determines that charging of the power storage means is not necessary, the supply time decrease change for reducing the supply time per unit time by the power supply means The power supply apparatus according to claim 2, further comprising: means. A receiver that receives radio waves from a vehicle electronic key that transmits radio waves including unique identification data, and extracts the identification data by demodulating the radio waves;
A control device for determining whether or not the identification data extracted by the receiving device matches the identification data recorded in advance in advance, and when each of the identification data matches, a control device that releases the door lock in the vehicle;
A door unlocking system comprising:
The receiving device is configured as a power consuming device according to any one of claims 1 to 3.
The said control apparatus is comprised as an electric power supply apparatus in any one of Claims 1-3. The door lock cancellation | release system characterized by these.

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