Patent Description:
<FIG> is a block diagram of conventional door latch system <NUM>. Door latch system <NUM> includes normal operation mechanism <NUM> and emergency operation mechanism <NUM>. Normal operation mechanism <NUM> includes door latch power supply device <NUM> that receives power supply from automotive battery <NUM>, and door latch motor <NUM> driven by door latch power supply device <NUM>. In normal operation mechanism <NUM> for operating in normal time, an instruction for placing door latch unit <NUM> in an unlatched state is received from door handle <NUM> to operate door latch power supply device <NUM> and door latch motor <NUM>.

Emergency operation mechanism <NUM>, which is a redundant function, places door latch unit <NUM> in an unlatched state, thereby enabling to enter vehicle <NUM> for maintenance when automotive battery <NUM> runs out, e.g., in the case where vehicle <NUM> is not moved for a long period of time. Emergency operation mechanism <NUM> includes mechanical latch mechanism <NUM> operating mechanically in response to an instruction for placing door latch unit <NUM> in an unlatched state from door handle <NUM>.

A conventional door latch system similar to door latch system <NUM> is disclosed in, e.g. PTL <NUM>.

<CIT> discloses a vehicle door locking system, which can receive power either from a vehicle battery of wirelessly from a battery of a portable vehicle key.

<CIT>discloses a vehicle door locking system, which can receive power either from a vehicle battery or from a power storage within the vehicle door locking system, which power storage is charged by the vehicle battery.

PTL <NUM>: International publication No. <CIT>.

A door latch power supply device includes an electricity storage unit, a charger, a discharger, a contactless power receiver, an input port configured to be connected to an external power supply, an output port configured to be connected to an actuator, and an operation signal receiver configured to receive an operation signal sent in response to an operation for opening a door. While an input voltage input to the input port is higher than or equal to a first input threshold, the charger operates using power supplied from the external power supply so as to cause a storage voltage of the electricity storage unit to become a first storage voltage value, and the discharger outputs power in the electricity storage unit to the output port to place the actuator in the unlatched state in response to the operation signal received by the operation signal receiver. While the input voltage is lower than the first input threshold, the charger operates using power supplied from the contactless power receiver so as to cause the storage voltage to become a second storage voltage value, and then the discharger outputs power in the electricity storage unit to the output port to place the actuator in the unlatched state in response to the operation signal received. The second storage voltage value is higher than the first storage voltage value. Another alternative door latch power supply device is provided in claim <NUM>.

This door latch power supply device reduces the weight of a vehicle.

<FIG> is a circuit block diagram of door latch power supply device <NUM> in accordance with an exemplary embodiment. Door latch power supply device <NUM> includes electricity storage unit <NUM>, charger <NUM>, discharger <NUM>, contactless power receiver <NUM>, input port <NUM>, output port <NUM>, operation signal receiver <NUM>, and controller <NUM>. Charger <NUM> is connected to charging path 13A of electricity storage unit <NUM> to charge electricity storage unit <NUM>. Discharger <NUM> is connected to discharging path 14A of electricity storage unit <NUM> to discharge electricity storage unit <NUM>. Contactless power receiver <NUM> connected to charger <NUM> is configured to charge electricity storage unit <NUM> without contact. Input port <NUM> is connected to charger <NUM>. Output port <NUM> is connected to discharger <NUM>. Operation signal receiver <NUM> configured to receive an operation signal generated in the outside of door latch power supply device <NUM>.

<FIG> is a block diagram of vehicle <NUM> including door latch power supply device <NUM>. <FIG> and <FIG> are timing charts of an operation of door latch power supply device <NUM>. The configuration and operation of door latch power supply device <NUM> will be described below.

Door latch power supply device <NUM>, automotive battery <NUM> connected to input port <NUM> of door latch power supply device <NUM>, actuator <NUM> connected to output port <NUM> of door latch power supply device <NUM>, and electric device 21A are mounted onto body <NUM> of vehicle <NUM>. Door <NUM> is provided in body <NUM>. Door handle <NUM> connected to operation signal receiver <NUM> of door latch power supply device <NUM> is disposed in door <NUM>. Automotive battery <NUM> is an external power supply provided outside door latch power supply device <NUM>, and is a rechargeable battery, such as a lead storage battery or a lithium ion battery, capable of charging and discharging. Electric device 21A may be, e.g. a car audio device and a car navigation device. Actuator <NUM> is configured to selectively provide a latched state in which door <NUM> is latched and an unlatched state in which door <NUM> is not latched. In the latched state, a fastener is engaged with door <NUM>, so that door <NUM> is latched and closed. In the unlatched state, a fastener is not engaged with door <NUM>, so that door <NUM> can be opened. In other words, in the unlatched state, an operator just pulls or pushes door <NUM>, thereby opening door <NUM>. If no power is output from output port <NUM> of door latch power supply device <NUM>, actuator <NUM> is in the latched state.

In accordance with the embodiment, actuator <NUM> is mounted onto body <NUM>. When an operator operates door handle <NUM>, actuator <NUM> is driven to operate as a result of that. Actuator <NUM>, however, may be a device for opening the door latch.

An operation of vehicle <NUM> and door latch power supply device <NUM> performed when an operator rides on vehicle <NUM> while vehicle <NUM> is not started will be described below. In other words, this operation is performed under a condition that vehicle <NUM> is left unused after being started and stopped.

An operator of vehicle <NUM> operates door handle <NUM> to open door <NUM>. As mentioned above, door handle <NUM> is connected to operation signal receiver <NUM> of door latch power supply device <NUM>. When an operator operates door handle <NUM>, operation signal receiver <NUM> receives an operation signal in response to the operation.

Door handle <NUM> may be connected to operation signal receiver <NUM> directly or indirectly. In other words, door handle <NUM> may transmit the operation signal, or an electric circuit other than door handle <NUM> linked to door handle <NUM> may transmit the operation signal.

Electricity storage unit <NUM> of door latch power supply device <NUM> includes one or more electricity storage elements. The electricity storage elements may employ rechargeable batteries or electric double layer capacitors, which can charge and discharge repetitively. The kind of electricity storage elements may be determined depending on an operation specification of door latch power supply device <NUM>. In accordance with the embodiment, door latch power supply device <NUM> employs an electric double layer capacitor as electricity storage unit <NUM>. Herein, the electric double layer capacitor is excellent in weight saving and characteristics related to large current discharge. <FIG> and <FIG> are timing charts showing an operation of door latch power supply device <NUM>. <FIG> and <FIG> show input voltage Vin, operation signal Sop, output voltage Vout, and storage voltage Vca. In <FIG> and <FIG>, horizontal axes indicate time, and vertical axes indicate the above-mentioned voltages and a value of the signal.

First, the operation of door latch power supply device <NUM> and vehicle <NUM> when input voltage Vin at input port <NUM> of door latch power supply device <NUM> is higher than or equal to input threshold Vi1 will be described with reference mainly to <FIG>. Input threshold Vi1 is determined to be a minimum value that can operate electric device 21A mounted on vehicle <NUM>. In door latch power supply device <NUM>, input threshold Vi2 lower than input threshold Vi1 is defined. Input threshold Vi2 is set to be a minimum value that can operate charger <NUM> and discharger <NUM>, or a minimum value required before a boost-up operation in order to obtain a predetermined voltage after the boost-up operation.

Input voltage Vin detected at input port <NUM> is a voltage of automotive battery <NUM>, and is compared with input threshold Vi1. When input voltage Vin is higher than or equal to input threshold Vi1, automotive battery <NUM> is determined to be in a preferable state without any deterioration. The operation of comparing input voltage Vin with input threshold Vi1 may be performed repetitively and periodically at predetermined periods when vehicle <NUM> is left unused, or may be performed when operation signal receiver <NUM> receives an operation signal.

When controller <NUM> determines that input voltage Vin is higher than or equal to input threshold Vi1, charger <NUM> starts operation. The operation of charger <NUM> may be either of a boost-up operation or a stepping-down operation. Charger <NUM> charges electricity storage unit <NUM> so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1. The operation of charger <NUM> which charges electricity storage unit <NUM> so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1 may be performed repetitively and periodically at predetermined periods when vehicle <NUM> is left unused, or may be performed when operation signal receiver <NUM> receives operation signal Sop, similarly to the comparing operation mentioned above.

When vehicle <NUM> is stopped last time after completing its start-up, controller <NUM> operates charger <NUM> and discharger <NUM> so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1 which is about <NUM>% or less of a full charge voltage of the electric double layer capacitor in consideration of a life time of the electric double layer capacitor of electricity storage unit <NUM>. After that, electricity storage unit <NUM> is left unused. This configuration hardly promotes degradation of electricity storage unit <NUM>. If being left unused during the same period of time, the electric double layer capacitor which constitutes electricity storage unit <NUM> hardly cause a deterioration in voltage as compared with automotive battery <NUM>. But if being left unused for a long time, storage voltage Vca decreases gradually. However, the decreasing amount of storage voltage Vca is small. Accordingly, the operation in which charger <NUM> charges storage voltage Vca of electricity storage unit <NUM> to storage voltage value Vc1 may be performed repetitively and periodically at predetermined periods when vehicle <NUM> is left unused, or may be performed when operation signal receiver <NUM> receives an operation signal. In both cases, the operation in which electricity storage unit <NUM> charges storage voltage Vca to storage voltage value Vc1 is completed in an extremely short period of time.

When an operator operates door handle <NUM> at timing T1, operation signal receiver <NUM> receives operation signal Sop. As mentioned above, electricity storage unit <NUM> is charged before timing T1 such that storage voltage Vca becomes storage voltage value Vc1. Alternatively, when operation signal receiver <NUM> receives operation signal Sop at timing T1, in response to this, charger <NUM> charges electricity storage unit <NUM> so as to cause storage voltage Vca to become storage voltage value Vc1 instantly in response to the signal. For the operation of charging electricity storage unit <NUM> before timing T1 such that storage voltage Vca becomes storage voltage value Vc1, charger <NUM> may start the above-mentioned operation when external signal receiver <NUM> of door latch power supply device <NUM> receives an auxiliary signal from, e.g. a transmitter or the like possessed by an operator. In other words, charger <NUM> may start the above-mentioned operation when door latch power supply device <NUM> detects the auxiliary signal transmitted from the transmitter held by the operator which is located away from vehicle <NUM> approaches vehicle <NUM>. External signal receiver <NUM> is provided in vehicle <NUM>. Information received by external signal receiver <NUM> is transmitted to door latch power supply device <NUM> although external signal receiver <NUM> is provided in door latch power supply device <NUM> in the figures.

In period PT12 from timing T1 to timing T2 in which an operator operates door handle <NUM>, or period PT13 from timing T1 to timing T3 which is longer than period PT12, discharger <NUM> outputs power in electricity storage unit <NUM> charged to have storage voltage value Vc1 through output port <NUM> to drive actuator <NUM>. In other words, in period PT12 or period PT13, the power in electricity storage unit <NUM> is used to place actuator <NUM> in the unlatched state and allow door <NUM> to be openable. The operation of discharger <NUM> may be either of a boost-up operation or a stepping-down operation.

The operation at timing T1 in which charger <NUM> charges electricity storage unit <NUM> so as to cause storage voltage Vca to become storage voltage value Vc1 in response to the operation of door handle <NUM> may be performed simultaneously to the operation in which discharger <NUM> discharges the power in electricity storage unit <NUM> to output port <NUM>. Alternatively, when an operator operates door handle <NUM> at timing T1, charger <NUM> may charge electricity storage unit <NUM> so as to cause storage voltage Vca to become storage voltage value Vc1. At subsequent timing T11, discharger <NUM> may discharge electricity storage unit <NUM> and output the power in electricity storage unit <NUM> to output port <NUM>. Alternatively, when an operator operates door handle <NUM> at timing T1, in response to operation signal Sop transmitted through the above-mentioned operation, charger <NUM> may first charge electricity storage unit <NUM> so as to cause storage voltage Vca to become storage voltage value Vc1. After that, discharger <NUM> may discharge electricity storage unit <NUM> and start outputting the power in electricity storage unit <NUM> to output port <NUM> at subsequent timing T11 when charger <NUM> completes the above-mentioned charging operation, or immediately after charger <NUM> completes the above-mentioned charging operation.

While input voltage Vin is higher than or equal to input threshold Vi1, storage voltage Vca is almost equal to storage voltage value Vc1. Therefore, the operation in which charger <NUM> charges electricity storage unit <NUM> at timing T1 so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1 may be performed simultaneously to the operation in which discharger <NUM> discharges electricity storage unit <NUM> and outputs the power in electricity storage unit <NUM> to output port <NUM>. Further, while input voltage Vin is higher than or equal to input threshold Vi1, automotive battery <NUM> is not deteriorated, i.e., is in a preferable state. Thus, even if storage voltage Vca of electricity storage unit <NUM> is storage voltage value Vc1 lower than a full charge state of the storage unit, power can be supplied to electricity storage unit <NUM> from charger <NUM> constantly. Therefore, discharger <NUM> can drive actuator <NUM> with no problem.

Next, an operation of door latch power supply device <NUM> and vehicle <NUM> at the time when input voltage Vin at input port <NUM> of door latch power supply device <NUM> is lower than input threshold Vi1 will be described mainly with reference to <FIG>.

Input voltage Vin detected by input port <NUM> is a voltage of automotive battery <NUM>. Input voltage Vin is compared with input threshold Vi1. When input voltage Vin is lower than input threshold Vi1, automotive battery <NUM> is determined to be deteriorated, i.e., not in a preferable state. Herein, the operation related to a comparison between input voltage Vin and input threshold Vi1 may be performed repetitively and periodically at predetermined periods when vehicle <NUM> is left unused, or may be performed when operation signal receiver <NUM> receives operation signal Sop.

The operations of comparison and determination mentioned here are performed by controller <NUM> described later. Controller <NUM> is able to operate at a low voltage even if the voltage of automotive battery <NUM> is low and automotive battery <NUM> is deteriorated, i.e., not in a preferable state. Therefore, fundamental control, comparison, and determination are performed almost constantly or at any timing. In other words, controller <NUM> can operate even if the output voltage of automotive battery <NUM> has a value lower than input threshold Vi1 although input threshold Vi1 is set as a voltage necessary to operate electric device 21A mounted on vehicle <NUM>, charger <NUM>, and discharger <NUM>. Charge indicator <NUM> may indicate that automotive battery <NUM> is deteriorated.

At the timing when external signal receiver <NUM> provided in door latch power supply device <NUM> receives an auxiliary signal from a transmitter possessed by an operator, controller <NUM> may start operation to perform determination and display.

Alternatively, based on the fact that actuator <NUM> is in the latched state without being energized, i.e., actuator <NUM> does not change to the unlatched state, an operator may estimate that automotive battery <NUM> has run out when operating door handle <NUM>. Typically, if vehicle <NUM> is not started over a long period of time, e.g., half a year or one or more years, or if power is continuously supplied to a load, such as a light of vehicle <NUM>, for a long time without charging, automotive battery <NUM> runs out. Therefore, if actuator <NUM> is in the latched state without being energized, i.e., does not change to the unlatched state, an operator may estimate or determined that automotive battery <NUM> runs out. If degradation of automotive battery <NUM> progresses significantly to cease operation of controller <NUM>, an operator estimates or determines that.

If input voltage Vin is determined to be lower than input threshold Vi1, neither charger <NUM> nor discharger <NUM> operate fundamentally, or controller <NUM> operates neither charger <NUM> nor discharger <NUM>. This situation corresponds to the state before timing T00 in <FIG>. For instance, when an operator operates door handle <NUM> at timing T00, if operation signal receiver <NUM> receives operation signal Sop and input voltage Vin is determined to be lower than input threshold Vi1 at timing T00, neither charger <NUM> nor discharger <NUM> operates.

In this case, power is supplied to contactless power receiver <NUM> from outside of vehicle <NUM>. Specifically, at timing T01, the operator causes contactless power supply unit <NUM>, which is a power supply separate from vehicle <NUM>, to approach contactless power receiver <NUM> of door latch power supply device <NUM> so as to supply power to contactless power receiver <NUM> from contactless power supply unit <NUM>. Thus, charger <NUM> starts the operation of charging electricity storage unit <NUM> at timing T01. The supply of power from contactless power supply unit <NUM> to contactless power receiver <NUM> is performed during period PT0102 from timing T01 to timing T02 until storage voltage Vca of electricity storage unit <NUM> reaches storage voltage value Vc2. In other words, the operation in which charger <NUM> charges electricity storage unit <NUM> is performed from timing T01 to timing T02. The operation of charger <NUM> may be either of a boost-up operation or a stepping-down operation.

In <FIG>, storage voltage Vca increases from timing T01 to timing T02 along a straight trajectory. The trajectory of storage voltage Vca changes depending on a coupling status between contactless power supply unit <NUM> and contactless power receiver <NUM>, or charge characteristics of electricity storage unit <NUM>. Therefore, the trajectory of storage voltage Vca is not necessarily a straight line. Further, in <FIG>, the supply of power from contactless power supply unit <NUM> to contactless power receiver <NUM> is performed continuously even after timing T01. The supply of power, however, may be completed at timing T02.

Next, after timing T02, i.e., after electricity storage unit <NUM> is charged completely until storage voltage Vca reaches storage voltage value Vc2, operation signal receiver <NUM> receives operation signal Sop when an operator operates door handle <NUM> at timing T03. In response to the signal, discharger <NUM> starts operation of discharging electricity storage unit <NUM> at timing T03. Furthermore, in period PT0304 from timing T03 to timing T04 in which the operator operates door handle <NUM>, or period PT0305 from timing T03 to timing T05 which is longer than period PT0304, discharger <NUM> outputs, to output port <NUM>, power in electricity storage unit <NUM>, which has been charged to cause storage voltage Vca to substantially become storage voltage value Vc2, so as to drive actuator <NUM>. In other words, during period PT0304 or period PT0305, actuator <NUM> is driven by the power in electricity storage unit <NUM>, thereby changing to the unlatched state from the latched state. The operation of discharger <NUM> may be any of a boost-up operation, a stepping-down operation, or an operation of discharging the voltage of electricity storage unit <NUM> as it is.

In period PT0305 from timing T03 to timing T05, limited power stored in electricity storage unit <NUM> is output to output port <NUM> from discharger <NUM> although no power is supplied to electricity storage unit <NUM> from automotive battery <NUM>. Accordingly, only discharger <NUM> is preferably operated during period PT0305 without operating charger <NUM>.

In the above-mentioned operation, if run-out of battery or large degradation occurs in automotive battery <NUM> when vehicle <NUM> is not started over a long period of time, door latch power supply device <NUM> places door <NUM> of vehicle <NUM> in the unlatched state, thereby enabling the operator to enter vehicle <NUM> to perform maintenance of vehicle <NUM>.

Conventional door latch system <NUM> shown in <FIG> includes mechanical latch mechanism <NUM> as emergency operation mechanism <NUM>. This configuration increases the volume and the weight of the system. The weight of vehicle <NUM> increases accordingly, and causes fuel consumption of vehicle <NUM> to deteriorate.

Door latch power supply device <NUM> in accordance with the embodiment does not include mechanical latch mechanism <NUM> which is a redundant function that operates as emergency operation mechanism <NUM> of conventional door latch system <NUM>. Thus, the weight of vehicle <NUM> is reduced accordingly.

In door latch power supply system <NUM> including door latch power supply device <NUM> and contactless power supply unit <NUM> which is a power supply located from vehicle <NUM>, power may be supplied to door latch power supply device <NUM> from another power supply, instead of contactless power supply unit <NUM>. Contactless power supply unit <NUM> may be driven by commercial power or a portable battery. A service of vehicle <NUM> may possess contactless power supply unit <NUM>. Alternatively, a contactless power supply device for portable communication equipment or the like may be used as contactless power supply unit <NUM>.

Storage voltage value Vc2 is higher than storage voltage value Vc1. As mentioned above, in consideration of a life time of electricity storage unit <NUM>, storage voltage value Vc1 is set to be lower than a full charge voltage of electricity storage unit <NUM>, i.e., is set to about <NUM>% of the full charge voltage, and is a value at which an influence on the life time is small. On the other hand, storage voltage value Vc2 corresponds to an electricity storage amount obtained by storing the power received from contactless power supply unit <NUM> when the power of automotive battery <NUM> is insufficient. Accordingly, if operable time of door latch power supply device <NUM> is long, storage voltage value Vc2 is preferably higher than storage voltage value Vc1, i.e., <NUM>% or more of the full charge voltage, or is set as a value of a full charge level.

Charge indicator <NUM> is preferably provided in any one of vehicle <NUM>, body <NUM>, door <NUM>, and door latch power supply devices <NUM>. Charge indicator <NUM> indicates an electricity storage completion state when electricity storage unit <NUM> is charged from contactless power supply unit <NUM> through contactless power receiver <NUM> and charger <NUM> to cause storage voltage Vca of electricity storage unit <NUM> to reach storage voltage value Vc2, in other words, when the power stored in electricity storage unit <NUM> reaches a value enough to drive actuator <NUM>. Charge indicator <NUM> allows an operator to visually recognize the charging state of electricity storage unit <NUM> easily, thereby enabling suitable power supply from contactless power supply unit <NUM>.

As mentioned above, while input voltage Vin is lower than input threshold Vi1, if operation signal receiver <NUM> receives operation signal Sop, charge indicator <NUM> may indicate that automotive battery <NUM> is in an abnormal state. Thus, the operator can visually recognize the state of automotive battery <NUM> easily.

The above-mentioned operation of door latch power supply device <NUM> and vehicle <NUM> have been described in both the case where the input voltage at input port <NUM> of door latch power supply device <NUM> is higher than or equal to input threshold Vi1, and the case where the input voltage at input port <NUM> of door latch power supply device <NUM> is lower than input threshold Vi1. In the case where the input voltage at input port <NUM> of door latch power supply device <NUM> is lower than input threshold Vi1, the above-mentioned operation is in an alternative solution divided with reference to a threshold of storage voltage Vca. This operation will be described below.

While input voltage Vin is lower than input threshold Vi1 and storage voltage Vca of electricity storage unit <NUM> is higher than or equal to storage voltage value Vc3, controller <NUM> does not operate charger <NUM>. At this moment, storage voltage Vca of electricity storage unit <NUM> is generated by the power which is charged when vehicle <NUM> is stopped last time after completing its start-up and which remains while decreasing, as mentioned above.

When operation signal Sop is received by operation signal receiver <NUM>, discharger <NUM> outputs power in electricity storage unit <NUM> to output port <NUM>. On the other hand, while input voltage Vin is lower than input threshold Vi1 and storage voltage Vca is lower than storage voltage value Vc3, charger <NUM> operates using power supplied from contactless power receiver <NUM> so as to cause storage voltage Vca to become storage voltage value Vc2. After that, when operation signal Sop is received, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM>.

Storage voltage value Vc3 is set to meet the following condition. Even in the case that input voltage Vin is lower than input threshold Vi1 and the power stored in automotive battery <NUM> is insufficient, while storage voltage Vca is higher than or equal to storage voltages Vc3 and power remains in electricity storage unit <NUM>, actuator <NUM> is placed in the unlatched state from the latched state operation signal Sop is received even if electricity storage unit <NUM> is not charged. Storage voltage value Vc3 may be lower than storage voltage value Vc1. Storage voltage value Vc3 is determined to be a minimum value that can operate charger <NUM> and discharger <NUM>, or a minimum value required before a boost-up operation in order to obtain a predetermined voltage in discharger <NUM> after the boost-up operation.

For instance, if input voltage Vin has a value enabling charger <NUM>, discharger <NUM>, and controller <NUM> to start or operate, although not enabling electric device 21A mounted on vehicle <NUM> to start or operate, charger <NUM> may be operated when operation signal receiver <NUM> receives operation signal Sop. In other words, this state corresponds to the case where input voltage Vin is lower than input threshold Vi1, and cannot start or operate electric device 21A mounted on vehicle <NUM>. Furthermore, this state corresponds to the case where input voltage Vin has a value enabling charger <NUM> and controller <NUM> to start or operate although input voltage Vin is lower than input threshold Vi1.

Under the above-mentioned condition, electricity storage unit <NUM> can be charged so as to cause storage voltage Vca to become storage voltage value Vc2 or storage voltage value Vc3 regardless of the value of storage voltage Vca before charging. When operation signal Sop is received, the power charged in electricity storage unit <NUM> is discharged, thereby allowing actuator <NUM> to be placed in the unlatched state in which door <NUM> is unlatched. Therefore, even when automotive battery <NUM> is deteriorated to a level disabling electric device 21A to operate, if automotive battery <NUM> is in a level enabling charger <NUM> to operate to charge electricity storage unit <NUM>, actuator <NUM> can be placed in the unlatched state.

When input voltage Vin is lower than the value enabling charger <NUM>, discharger <NUM>, and controller <NUM> to start or operate, charger <NUM> is operated to charge electricity storage unit <NUM> so as to cause the storage voltage of electricity storage unit <NUM> to become storage voltage value Vc2 using power supplied from contactless power receiver <NUM>, as mentioned above. Alternatively, the power supplied from contactless power receiver <NUM> may be used to energize controller <NUM>, thereby performing to energize controller <NUM> and charge electricity storage unit <NUM> simultaneously.

In the above description, a relationship between the operation of each element constituting door latch power supply device <NUM> and operation signal Sop from door handle <NUM> or the voltage of automotive battery <NUM> are shown. Door latch power supply device <NUM> shown in <FIG> and <FIG> does not necessarily include controller <NUM>. In this case, charger <NUM> and discharger <NUM> are operated based on input voltage Vin, storage voltage Vca, and operation signal Sop.

<FIG> is a block diagram of vehicle <NUM> including another door latch power supply devices 11a in accordance with the embodiment. Door latch power supply device 11a includes controller <NUM>.

In door latch power supply device 11a, controller <NUM> detects and determines input voltage Vin and storage voltage Vca, and detects operation signal Sop, and controls operation of charger <NUM> and discharger <NUM>. Controller <NUM> is not necessarily arranged integrally as an element or a circuit. Controller <NUM> may be arranged such that the function thereof is distributed to electricity storage unit <NUM>, charger <NUM>, and discharger <NUM>. Further, power for driving controller <NUM> is supplied from automotive battery <NUM> or electricity storage unit <NUM>. Further, when the power stored in automotive battery <NUM> and electricity storage unit <NUM> is insufficient, i.e., not enough to drive controller <NUM>, if power is supplied to contactless power receiver <NUM> from contactless power supply unit <NUM>, the power is used to energize controller <NUM> and perform the above-mentioned operation.

As mentioned above, while the input voltage at input port <NUM> is higher than or equal to the input threshold, charger <NUM> operates so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1. In response to operation signal Sop received by operation signal receiver <NUM>, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM>.

Further, while the input voltage at input port <NUM> is lower than input threshold Vi1, charger <NUM> operates so as to storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc2 using power supplied from contactless power receiver <NUM>. After that, in response to operation signal Sop received by operation signal receiver <NUM>, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM>.

With the above configuration and operation, even if the power stored inside door latch power supply device <NUM> (11a) or inside vehicle <NUM>, such as automotive battery <NUM> mounted on vehicle <NUM>, is decreased to a level disabling to drive actuator <NUM>, door latch power supply device <NUM> (11a) can easily supply power for driving actuator <NUM> since door latch power supply device <NUM> (11a) employs contactless power supply unit <NUM> to charge electricity storage unit <NUM> from the outside of vehicle <NUM>, i.e., the outside of door latch power supply device <NUM> (11a), by contactless power supply.

Accordingly, even if automotive battery <NUM> runs out while vehicle <NUM> is started over a long period of time, door latch power supply device <NUM> (11a) can drive actuator <NUM>, so that door <NUM> of vehicle <NUM> can be placed in the unlatched state. Therefore, an operator can enter vehicle <NUM> to perform maintenance of vehicle <NUM>. As a result, the mechanical latch mechanism which is a redundant function that operates as an emergency operation mechanism, can be eliminated, thereby reducing the weight of vehicle <NUM>.

As mentioned above, door latch power supply device <NUM> (11a) is configured to be connected to actuator <NUM> and an external power supply (automotive battery <NUM>). Actuator <NUM> is configured to provide a latched state in which door <NUM> is latched and an unlatched state in which door <NUM> is not latched. Door latch power supply device <NUM> (11a) includes electricity storage unit <NUM>, charger <NUM> connected to charging path 13A of electricity storage unit <NUM>, discharger <NUM> connected to discharging path 14A of electricity storage unit <NUM>, contactless power receiver <NUM> connected to charger <NUM> and configured to receive power without contact, input port <NUM> connected to charger <NUM> and configured to be connected to an external power supply, output port <NUM> connected to discharger <NUM>, and operation signal receiver <NUM> configured to receive operation signal Sop sent in response to an operation of opening door <NUM>. Input port <NUM> is configured to be connected to the external power supply. Output port <NUM> is configured to be connected to actuator <NUM>. While input voltage Vin to be input to input port <NUM> is higher than or equal to input threshold Vi1, charger <NUM> operates using power supplied from the external power supply so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1. At this moment, in response to operation signal Sop received by operation signal receiver <NUM>, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state. While input voltage Vin is lower than input threshold Vi1, charger <NUM> operates using power supplied from contactless power receiver <NUM> so as to cause storage voltage Vca to become storage voltage value Vc2. Then, in response to operation signal Sop received, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state.

Electricity storage unit <NUM> includes an electric double layer capacitor. Storage voltage value Vc1 is lower than a full charge voltage of the electric double layer capacitor.

Storage voltage value Vc2 is higher than storage voltage value Vc1.

When storage voltage Vca is increased to reach a value equal to or higher than storage voltages Vc2 by the power supplied from contactless power receiver <NUM>, charge indicator <NUM> indicates an electricity storage completion state.

While input voltage Vin is higher than or equal to input threshold Vi1, charger <NUM> operates in response to an auxiliary signal sent by an operator so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1 using power supplied from the external power supply. While input voltage Vin is lower than input threshold Vi1, charger <NUM> operates in response to the auxiliary signal so as to cause storage voltage Vca to become storage voltage value Vc2 using power supplied from contactless power receiver <NUM>. Then, in response to operation signal Sop received, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state.

While input voltage Vin is higher than or equal to input threshold Vi1, charger <NUM> operates using the power supplied from the external power supply so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1. At this moment, in response to operation signal Sop received by operation signal receiver <NUM>, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state. While input voltage Vin is lower than input threshold Vi1 and storage voltage Vca is higher than or equal to storage voltage value Vc3, charger <NUM> does not operate, and discharger <NUM> outputs power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state in response to operation signal Sop received by operation signal receiver <NUM>. While input voltage Vin is lower than input threshold Vi1 and storage voltage Vca is lower than storage voltage value Vc3, charger <NUM> operates using the power supplied from contactless power receiver <NUM> so as to cause storage voltage Vca to become storage voltage value Vc2. Then, in response to operation signal Sop received, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state.

While input voltage Vin is higher than or equal to input threshold Vi1, charger <NUM> operates using the power supplied from the external power supply so as to cause storage voltage Vca of electricity storage unit <NUM> to become storage voltage value Vc1. At this moment, in response to operation signal Sop received by operation signal receiver <NUM>, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state. While input voltage Vin is lower than input threshold Vi1 and higher than or equal to input threshold Vi2 that can operate charger <NUM> and discharger <NUM>, charger <NUM> and discharger <NUM> operate to output power in electricity storage unit <NUM> to output port <NUM> in response to operation signal Sop received by operation signal receiver <NUM>, so that actuator <NUM> is placed in the unlatched state from the latched state. While input voltage Vin is lower than input threshold Vi1 and lower than input threshold Vi2, charger <NUM> operates using the power supplied from contactless power receiver <NUM> so as to cause storage voltage Vca to become storage voltage value Vc2. Then, in response to operation signal Sop received, discharger <NUM> outputs the power in electricity storage unit <NUM> to output port <NUM> to place actuator <NUM> in the unlatched state from the latched state.

Claim 1:
A door latch power supply device (<NUM>) configured to be connected to an actuator (<NUM>) and an external power supply (<NUM>), the actuator (<NUM>) providing a latched state in which a door (<NUM>) is latched and an unlatched state in which the door (<NUM>) is not latched, the door latch power supply device (<NUM>) comprising:
an electricity storage unit (<NUM>);
a charger (<NUM>) connected to a charging path of the electricity storage unit (<NUM>);
a discharger (<NUM>) connected to a discharging path of the electricity storage unit (<NUM>);
a contactless power receiver (<NUM>) connected to the charger (<NUM>) and configured to receive power without contact;
an input port (<NUM>), the input port (<NUM>) being configured to be connected to the external power supply (<NUM>);
an output port (<NUM>) connected to the discharger (<NUM>), the output port (<NUM>) being configured to be connected to the actuator (<NUM>); and
an operation signal receiver (<NUM>) configured to receive an operation signal sent in response to an operation for opening the door (<NUM>), wherein
while an input voltage input to the input port (<NUM>) is lower than a first input threshold, the charger (<NUM>) is configured to operate using power supplied from the contactless power receiver (<NUM>) so as to cause a storage voltage (Vca) of the electricity storage unit (<NUM>) to become a second storage voltage value (Vc2), and then the discharger (<NUM>) is configured to output power stored in the electricity storage unit (<NUM>) to the output port (<NUM>) to place the actuator (<NUM>) in the unlatched state in response to the operation signal received by the operation signal receiver (<NUM>),
characterized in that the input port (<NUM>) is connected to the charger (<NUM>),
wherein
while the input voltage input to the input port (<NUM>) is higher than or equal to the first input threshold, the charger (<NUM>) is configured to operate using power supplied from the external power supply (<NUM>) so as to cause the storage voltage (Vca) of the electricity storage unit (<NUM>) to become a first storage voltage value (Vc1), and the discharger (<NUM>) is configured to output power stored in the electricity storage unit (<NUM>) to the output port (<NUM>) to place the actuator (<NUM>) in the unlatched state in response to the operation signal received by the operation signal receiver (<NUM>), and
the second storage voltage value (Vc2) is higher than the first storage voltage value (Vc1).