JP6305152B2 - Power receiving device, power feeding system, power receiving device control method, and program - Google Patents

Description

  The present invention relates to a technique for switching and receiving power from among a plurality of power supplies.

  In recent years, a technique for supplying data and power using an Ethernet (registered trademark) cable has been known. This is in conformity with IEEE 802.3at defined as an international standard, and is referred to as Power Over Ethernet (registered trademark) (PoE). In PoE, power is supplied from a power source device (Power Source Equipment (PSE)) to a power receiving device (Powered Device (PD)). With PoE, which has been standardized in IEEE 802.3af, it is possible to supply power from the PSE to the PD up to 12.95W.

  Furthermore, according to the IEEE 802.3at standard, which is an extension of IEEE 802.3af, the PD can select the maximum power to be supplied from the PSE to the PD in PoE. When Type 1 is selected, PD can receive power up to 12.95 W from PSE. In addition, when Type 2 is selected, PD can receive power up to 25.5 W from PSE.

  In PoE, in order to prevent an excessive current from flowing through the Ethernet (registered trademark) cable, the PSE has a function of stopping power supply to the PD when a predetermined current or more is consumed.

  The IEEE 802.3at standard stipulates that when the PSE declares Type 1 as a power supply type for supplying power to the PD, the upper limit of the current flowing through the PD is limited to 400 mA. In the IEEE 802.3at standard, when Type 2 is selected as the power supply type, the current flowing from the PSE to the PD is less than 80 msec after the voltage received by the PD from the PSE reaches a predetermined voltage. The upper limit is limited to 400 mA, for example. After 80 msec, the amount of current flowing through the PD can be made larger than 400 mA.

  Conventionally, a power receiving device that can receive power from a plurality of power sources having different voltages is known. For example, it is possible to receive power from a power source (PSE) compatible with PoE conforming to IEEE 802.3at and a general-purpose power source such as an AC adapter, and a power receiving apparatus that selects and receives one of these power sources Known (for example, Patent Document 1).

  Here, the power receiving device (PD) connected to the first power source (for example, general-purpose power source) and the second power source (for example, PSE) is switched from the state operating with the first power source to the state operating with the second power source. And so-called inrush current may occur temporarily. This inrush current is the amount of current consumed while the power receiving device is operating on the first power source, and the power receiving device temporarily draws from the second power source after switching from the first power source to the second power source. This occurs because of

  Here, when the second power supply has a function of limiting the amount of current to be supplied when power supply is started, there is a problem that the second power supply interrupts power supply when such an inrush current occurs.

  For example, as described above, PoE has a function of stopping the power feeding operation when a current larger than the limit value (maximum 400 mA) is drawn from the PD at the time of startup. Therefore, in the above example, if the inrush current temporarily flows after the power source is switched from the general-purpose power source to the PSE, the PSE stops supplying power.

  In order to prevent the occurrence of such inrush current, for example, Patent Document 2 discloses that the input voltage from the general-purpose power source is boosted to reduce the voltage difference from the PSE. In this way, when the power source is switched, even if an inrush current occurs, the current amount limit is not exceeded, and the power feeding device is prevented from stopping power feeding.

JP 2007-36832 A JP2012-95502

  In the conventional method, when power is supplied with Type 2 where the amount of power supplied is larger than Type 1, when the power is switched from the general-purpose power source to the PSE, a function for preventing overcurrent operates in the power supply device. The PD has a problem that it cannot receive power.

  That is, the current flowing from the general-purpose power source to the PD exceeds 400 mA. Therefore, if the power supply for supplying power to the PD is switched from the general-purpose power supply to the PSE before the upper limit value of the current limit of the PSE corresponding to PoE increases, the current flowing in the PD temporarily exceeds 400 mA due to the inrush current. Current is drawn from the PSE. And the function which prevents an overcurrent operate | moves in PSE, and the supply of the electric power from PSE will be stopped.

  As described above, in the conventional method, when a power receiving apparatus receives power by switching a plurality of power sources having different voltages, power supply from the power source may be stopped.

  In order to solve the above object, a power receiving device according to the present invention receives power from a first power source and receives power via a communication line from a second power source that limits the amount of current to be output for a predetermined period. A power receiving means; an output means for outputting the power received by the power receiving means to a load; and a power supply for supplying the power output by the output means to the load. The voltage input from the second power supply is a predetermined voltage. Control means for controlling to switch from the first power source to the second power source after the predetermined period of time has passed.

  In this way, when the power receiving device receives power by switching the power to be supplied from among a plurality of power sources connected to the power receiving device, the power supply from the power source can be prevented from being stopped when the power is switched.

The block diagram which shows an example of a structure of the electric power feeding system in 1st Embodiment. The follow chart figure which shows the process of the power supply circuit in 1st Embodiment. The flowchart figure which shows the process of the control part 116 in 1st Embodiment. The flowchart figure which shows the process of the 2nd detection part 108 and the delay part 115 in 1st Embodiment. The figure which shows the waveform of the voltage in the electric power feeding system in 1st Embodiment, and an electric current. The block diagram which shows an example of a structure of the power supply circuit in 2nd Embodiment.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

<First Embodiment>
A configuration example of a power feeding system according to the first embodiment of the present invention is shown in FIG. The power receiving device 120 is connected to the first power source 101 and the second power source 102 and can receive power from the respective power sources.

  The first power supply 101 is a power supply that does not have a function of supplying power by limiting a current when the power supply is turned on. For example, the first power source 101 can be a general-purpose power source such as an AC adapter or an AC power source. The first power source is assumed to be a power source that supplies power at a lower voltage than the second power source 102 described later. For example, the first power source may be a power source that generates power from AC 100.0V to DC 12.0V using an AC adapter, or a power source that generates power from AC 100.0V to AC 24.0V. In the present embodiment, the case where the first power supply outputs DC 12.0V will be described.

  The second power supply 102 is a power supply having a function of supplying power while limiting a current to be supplied. The second power supply 102 limits the amount of current to be output for a predetermined period. In the present embodiment, the second power source 102 is connected to the power receiving apparatus 120 via a communication line (network). The second power supply 102 supplies power to the power receiving device 120 via the communication line. As the communication line, for example, an Ethernet (registered trademark) cable can be used.

  For example, the second power source 102 is a power supply device (PSE, Power Source Equipment) in PoE. In PoE, two types of power feeding methods can be used. In this embodiment, the power feeding method may be any power feeding method.

  In the present embodiment, the second power source 102 receives power when a current greater than or equal to a predetermined value flows from the second power source 102 until a predetermined time elapses after the voltage input to the power receiving device 120 reaches the predetermined voltage. Stop supplying. For example, if a current of 400 mA or more flows from the second power supply 102 before 80 msec elapses after the voltage input from the second power supply 102 to the power receiving device 120 reaches 42.0 V, the supply of power is stopped. .

  Next, a configuration of a power supply circuit in the power receiving device 120 will be described with reference to FIG.

  The rectifier 103 receives power from the first power supply 101. The rectifying unit 104 receives power from the second power source 102 via a communication line such as an Ethernet (registered trademark) cable. The rectifying unit 103 and the rectifying unit 104 constitute a power receiving unit. The rectification unit 103 and the rectification unit 104 perform full-wave rectification that converts an alternating current power source into direct current. As the rectifier 103 and the rectifier 104, for example, a diode bridge can be used.

  The smoothing unit 105 smoothes the waveform of the current output from the rectifying unit 103. Further, the smoothing unit 106 smoothes the waveform of the current output from the rectifying unit 104. As the smoothing unit 105 and the smoothing unit 106, for example, capacitors can be used.

  The first detection unit 107 detects that power is supplied from the first power supply 101. For example, the first detection unit 107 detects whether power is input from a general-purpose power source. When detecting that power supply from the first power source is started, the first detection unit 107 notifies the boosting unit 109.

  The second detection unit 108 detects that power can be supplied from the second power source 102 to a load unit 118 described later. In this embodiment, after the second power supply 102 is activated, when the voltage input from the second power supply 102 to the power receiving device 120 reaches a predetermined voltage (for example, 42.0 V), the switch of the switch unit 111 is turned on. . In addition, power can be supplied from the second power supply 102 to the circuits after the switch unit 111. The second detection unit 108 detects that the voltage input from the second power supply 102 to the power receiving device 120 has reached a predetermined voltage. When the second power supply 102 is a PSE that conforms to the IEEE 802.3at standard, the predetermined voltage is, for example, a start-up voltage (PD Power supply turn on voltage) defined in the IEEE 802.3at standard.

  Further, the second detection unit 108 notifies the delay unit 110 described later that power supply from the second power source 102 to the load unit 118 is possible. In addition, the second detection unit 108 detects that the second power source 102 has been disconnected from the power receiving apparatus 120 by a user operation or the like. The second detection unit 108 notifies the later-described delay unit 110 that the second power source 102 has been disconnected from the power receiving apparatus 120.

  The booster 109 boosts the voltage of the power supplied from the first power supply 101. The boosting unit 109 outputs the boosted voltage to the first output unit 112. The booster 109 can be constituted by a booster circuit, for example. In this embodiment, an example will be described in which the voltage of the first power supply 101 is boosted so that the boosted voltage is equal to or higher than the voltage output from the second power supply 102. For example, the boosting unit 109 boosts the voltage 12.0V output from the first power supply 101 and changes the voltage between V1 shown in FIG. 1 to a voltage of 57.0V.

  The delay unit 110 outputs to the booster 109 an enable signal for causing the booster 109 to stop boosting. However, boosting of the boosting unit 109 is not necessarily stopped by the enable signal. When the booster 109 receives the enable signal, the voltage output from the booster 109 may be lower than the voltage input from the second power supply 102. The timing at which the delay unit 110 outputs the enable signal to the boosting unit 109 is controlled by the control unit 116 described later.

  A case where the control unit 116 instructs the delay unit 110 to provide a delay time between time T0 and time T1 will be described. Here, the time T0 is a time at which the delay unit 110 receives from the second detection unit 108 a notification (detection signal) indicating that the voltage input from the second power supply 102 to the power receiving device 120 has reached a predetermined activation voltage. It is. Time T1 is a time at which the delay unit 110 outputs an enable signal in order to stop the boosting of the boosting unit 109. The delay unit 110 outputs an enable signal to the boosting unit 109 after a predetermined delay time has elapsed after receiving the detection signal from the second detection unit 108.

  On the other hand, when the control unit 116 does not instruct the delay unit 110 to provide a delay time between T0 and T1, the delay unit 110 receives a detection signal from the second detection unit 108 and then receives a predetermined delay time. The enable signal is output to the booster 109 without waiting.

  The enable signal is output not only when the output timing of the enable signal is determined based on the time when the notification is received from the second detection unit 108 but, for example, when the classification processing of the power receiving apparatus 120 described later is completed. Timing may be determined.

  The control unit 116 supplies the power to the load unit 118 from the first power source 101 after a predetermined period has elapsed after the voltage input from the second power source 102 reaches the predetermined voltage. Control is performed so as to switch to the two power sources 102. The control unit 116 controls the delay unit 110 according to power consumption of a load unit 118 described later. The power consumption of the load unit 118 is determined from the current value measured using the measurement unit 115 described later shown in FIG. 1 and the voltage value input to the conversion unit 117. Details of the control by the control unit 116 will be described later with reference to the flowchart of FIG.

  The switch unit 111 switches whether or not the power supplied from the second power source 102 can be supplied to the circuits after the switch unit 111. When the voltage input from the second power source 102 reaches a predetermined voltage (for example, 42.0 V), the switch unit 111 enables the power from the second power source 102 to be supplied to the second output unit 112. In this embodiment, the switch unit 111 turns on the switch when the voltage input from the second power source 102 to the switch unit 111 reaches a predetermined activation voltage (for example, 42.0 V) after the second power source 102 is activated. To do. When the switch is turned on, power can be supplied from the second power supply 102 to the conversion unit 117. The switch unit 111 is, for example, a PoE control device that conforms to the IEEE 802.3at standard, and includes a PoE power supply switch therein.

  Here, in the IEEE 802.3at standard, power supply from the PSE to the PD is started by the following procedure. First, PSE detects PD. The PSE performs a process of detecting a power receiving device (PD) that can receive power by PoE among devices connected to the PSE via an Ethernet (registered trademark) cable. When the PD is detected, the PSE then classifies the detected PD. The upper limit of the current value that the PSE supplies to the PD is determined by the classification of the PD. When the PD is detected and classified and the PD determines that the voltage input from the PSE has reached a predetermined activation voltage, the PSE can supply power to the load unit 118 included in the PD. Details of PD detection and classification will be described later.

  The switch unit 111 outputs a PD response to a signal transmitted from the PSE in the above-described processing for detecting and classifying the PD. When the PD detection and classification process is completed, the switch unit 111 turns on the switch to generate a voltage at V2 in FIG.

  The first output unit 112 outputs the power received by the rectifying unit 103 and output from the boosting unit 109 to the conversion unit 117 and the load unit 118. The second output unit 113 outputs the electric power output from the second power supply 102 and received by the rectifying unit 104 to the conversion unit 117 and the load unit 118. Each of the first output unit and the second output unit can be constituted by a diode, for example. Of the voltages input to the first output unit and the second output unit, the power having the higher voltage is output to the conversion unit 117. Therefore, of the power output from the boosting unit 109 and the power input from the second power supply 102, the power having the higher voltage is supplied to the conversion unit 117 and the load unit 118.

  The accumulation unit 114 accumulates the power output from the second power source 102. The electric power stored in the storage unit 114 is supplied to the conversion unit 117 in the subsequent stage. The storage unit 114 can be a capacitor, for example.

  The measurement unit 115 is used by the above-described control unit 116 to acquire the amount of current consumed by the load unit 118. The measurement unit 115 can measure the amount of current using, for example, a resistor. Alternatively, as a means for measuring the amount of current, the amount of current may be measured using a method using a coil typified by a current transformer or a sensor method typified by a Hall element.

  The converter 117 converts the voltage input from the first power supply 101 and the second power supply 102 into a desired DC voltage. For example, the voltage of PSE 48.0V is converted to 12.0V voltage or the like by a transformer (not shown) or the like. The conversion unit 117 insulates the load unit 118 from other circuit configurations.

  The load unit 118 includes a load circuit. For example, the load unit 118 is assumed to be connected to an electronic device such as a network camera. The load unit 118 is, for example, an imaging device that generates a captured image. Further, the load unit 118 may include a motor for changing the imaging direction of the imaging device, a heater used to warm the camera to a temperature at which the imaging device can be driven in a cold region, or the like. . In the present embodiment, the case where the load unit 118 is included in the power receiving device 120 will be described, but the present invention is not limited thereto. The load unit 118 may be a device independent of the power receiving device 120. For example, the load unit 118 may be a device that can be disconnected from the power receiving device 120.

  Next, the operation of the power supply circuit according to this embodiment will be described with reference to the flowcharts of FIGS. First, a case where power from the first power supply 101 is input to the power supply circuit (Yes in S201) will be described with reference to FIG. When the first detection unit 107 detects the input of power from the first power supply 101, the boosting unit 109 starts boosting (S202). In the present embodiment, the booster 109 boosts the voltage input from the first power supply 101 so as to be higher than a predetermined voltage (for example, 42.0 V). In this embodiment, for example, the boosting unit 109 boosts the voltage of 12.0V input from the first power supply 101 to 57.0V.

  When the power from the first power supply 101 is input to the power supply circuit and the power from the second power supply 102 is not input (No in S203), the power from the first power supply 101 is converted to the converter 117 and the load. Is input to the unit 118 (S204). That is, the voltage output from the first power supply 101 and boosted by the boosting unit 109 is applied to the conversion unit 117 via the first output unit 112. In this way, when only the power of the first power supply 101 is input to the power supply circuit among the first and second power supplies, the power from the first power supply 101 is input to the conversion unit 117.

  When the second power supply 102 is connected to the power receiving apparatus 120 while the power from the first power supply 101 is being input to the power supply circuit (Yes in S203), the second power supply 102 starts to supply power. The predetermined procedure is executed (S205). While the procedure of step S205 is not completed (No in S206), the process of step S203 is repeatedly executed. The processing in step S205 is detection processing and classification processing of the power receiving device 120. The procedure executed in step S205 will be described later. When the classification process is completed, the voltage output from the second power supply 102 gradually increases to the power supply voltage (for example, 48.0 V).

  When the second detection unit 108 determines that the voltage input from the second power supply 102 has reached a predetermined voltage (for example, 42.0 V), the switch unit 111 turns on the switch (S207). Subsequently, voltage control of power input from the first power supply 101 is performed under the control of the control unit 116 (S208). In step S <b> 208, it is determined according to the power consumption of the power receiving device 120 whether or not to continue the boosting in the boosting unit 109. When it is determined that the boosting is to be stopped, the boosting by the boosting unit 109 is stopped and the voltage output from the first output unit 112 from the first power supply 101 is decreased. Details of the processing in step S208 will be described later with reference to FIG.

  When the processing in step S208 is completed, power from the power source determined according to the control in step S208 out of the first power source and the second power source is input to the conversion unit 117 and the load unit 118 (S209). When the boosting of the boosting unit 109 is stopped in step S208, the voltage output from the first output unit 112 decreases, and the voltage output from the first output unit 112 is higher than the voltage output from the second output unit 113. Lower. Then, the output unit that outputs power to the conversion unit 117 and the load unit 118 is switched from the first output unit 112 to the second output unit 113. That is, the power source that supplies power to the conversion unit 117 and the load unit 118 is switched from the first power source 101 to the second power source 102. On the other hand, when the boosting is not stopped in step S208, power supply from the first power supply 101 to the converters 117 and 118 is continued.

  Next, a case where power is not input from the first power supply 101 to the power supply circuit (No in S201) will be described. When power from the first power supply 101 is not input and power from the second power supply is input (Yes in S210), after the processing of step S211 and step S212 is executed, the switch unit 111 Turns on the switch (S213). And the electric power from the 2nd power supply 102 is input into the conversion part 117 (S214). Here, since the process in step S211 is the same as the process in step S205, the description thereof is omitted.

  In this embodiment, after the power from the second power source 102 is input to the power circuit, even if the power from the first power source 101 is input to the power circuit, the power from the second power source 102 is converted into the converter 117 and the load. It is assumed that the input continues to the unit 118. While receiving the detection notification of the second power supply 102 from the second detection unit 108, the boosting unit 109 does not boost the power of the first power supply 101. Then, the first output unit 112 and the second output unit 113 convert the power from the second power source 102 (for example, 48.0V) having a higher voltage than the first power source 101 (for example, 12.0V) with priority. Input to the unit 117 and the load unit 118. If power is not input from both the first and second power sources, the process of step S201 is repeated.

  Next, the process performed in step S205 and step S211 shown in FIG. 2 will be described. In the present embodiment, a case where power is received from the second power source 102 according to a procedure defined in IEEE 802.3at will be described, but the present invention is not limited to this. In the present embodiment, the second power supply 102 starts power feeding to the power receiving apparatus 120 after performing the detection process and the classification process of the power receiving apparatus 120.

  First, the second power supply 102 detects a power receiving device that supports PoE. The second power supply 102 detects a power receiving device having a predetermined resistance value (for example, 19.0 to 26.5 KΩ) as a power receiving device corresponding to PoE.

  Next, the second power supply 102 classifies the detected power receiving device 120. The second power supply 102 determines the power to be supplied to the power receiving device 120 according to the resistance value of the resistor included in the power receiving device 120. The detection process and the classification process will be described later with reference to FIGS. The resistance used for the detection process and the classification process is included in the switch unit 111 of the power receiving device 120.

  In the present embodiment, the power receiving device 120 can select the maximum power supplied from the second power source 102 to the power receiving device 120. The power receiving device 120 can receive power up to 12.95 W from the second power source 102 when Type 1 is selected as the power feeding type for feeding power to the second power source 102 (PSE). The power receiving device 120 can receive power from the second power supply 102 up to 25.5 W when Type 2 is selected as the power supply type.

  When the classification of the power consumption of the power receiving apparatus 120 is completed, the second power supply 102 increases the voltage of the output power and outputs the power corresponding to the classification result of the power receiving apparatus 120 to the power receiving apparatus 120. When the voltage input to the power receiving device 120 by the second power supply 102 reaches a predetermined voltage, the switch unit 111 of the power receiving device 120 is turned on, and supply of power to the power receiving device 120 is started.

  Next, details of the processing of step S208 and step S209 of FIG. 2 will be described using the flowcharts of FIGS. 3A, 3B, 4A, and 4B. The process illustrated in FIG. 3A is a process executed by the control unit 116 in step S208. In the form in which the control unit 116 includes a processor, the processing flow of FIG. 3A shows a program for causing the processor to execute the procedure shown in FIG. This processor is a computer and executes a program read from a storage unit (not shown). The flowchart shown in FIG. 3B is a diagram illustrating operations of the first output unit 112 and the second output unit 113 in step S209.

  The process illustrated in FIG. 4A is a process executed by the second detection unit 108 in step S208. The process shown in FIG. 4B is a process executed by the delay unit 110 in step S208. In the form in which the delay unit 110 includes a processor, the processing flow in FIG. 4B shows a program for causing the processor to execute the procedure shown in FIG. This processor is a computer and executes a program read from a storage unit (not shown).

  First, the processing of the control unit 116 in S208 will be described with reference to FIG. When power supply from the second power supply 102 is started, the control unit 116 consumes power of the load unit 118 based on the current value measured using the measurement unit 115 and the voltage value input to the conversion unit 117. Quantity information is acquired (S301).

  Next, the control unit 116 determines whether the power consumption acquired in step 301 is equal to or lower than the first power (S302). Here, the first power is an upper limit value of power that can be received when the power receiving apparatus 120 requests the second power source 102 for the above-described Type 1 as the power supply type. Here, a case where the first power is 12.95 W will be described. In step S301, in addition to performing the determination based on the power consumption value, it may be determined whether the power supply type requested by the power receiving apparatus 120 to the second power supply 102 is Type1 or Type2. In this case, when the power receiving apparatus 120 requests Type 1, the process proceeds from step S302 to step S303, and when the power receiving apparatus 120 requests Type 2, the process proceeds from step S302 to S304.

  When the power consumption acquired in step S301 is equal to or lower than the first power (Yes in S302), the control unit 116 controls the delay unit 110 to output an enable signal from the delay unit 110 to the boosting unit 109. . This enable signal is a signal for causing the booster 109 to stop boosting. In step S303, the control unit 116 instructs the delay unit 110 to output an enable signal without waiting for a predetermined delay time. When the delay unit 110 receives a notification indicating that the voltage input from the second power supply 102 has reached a predetermined voltage from the second detection unit 108, the delay unit 110 stops boosting the boost unit 109 without waiting for a predetermined delay time. Let

  In this way, when the power consumption of the load unit 118 is equal to or lower than the predetermined power, the boosting of the boosting unit 109 is limited within a predetermined period after the voltage input from the second power supply 102 reaches the predetermined voltage. To do. However, the control unit 116 may stop the boosting of the boosting unit 109 after waiting for the delay time set by the delaying unit 110 in step S303.

  When the boosting by the boosting unit 109 is stopped, the power voltage (for example, 48.0) input from the second power source 102 is higher than the power voltage (for example, 12.0 V) input from the first power source 101. Get higher. Accordingly, the voltage from the second power supply 102 is applied to the conversion unit 117 by the operations of the first output unit 112 and the second output unit 113. In this way, the power from the second power supply 102 is input to the conversion unit 117. In this way, the power source that supplies power to the conversion unit 117 and the load unit 118 is switched from the first power source 101 to the second power source 102.

  Here, since the power receiving apparatus 120 switches the power supply from the state where the booster 109 boosts the voltage of the power input from the first power supply 101 to the second power supply 102, the second power supply 102 is caused by the occurrence of an inrush current. Can be prevented from stopping power feeding.

  For example, when the power received by the power receiving apparatus 120 is 12.95 W, when the voltage of the first power supply 101 is boosted (for example, boosted to 57.0 V) and supplied, the power is about 0.23 A (≈12. 95W / 57.0V) flows through the power receiving device. In addition, when the power received by the power receiving apparatus 120 is 12.95 W, when a power is supplied from the second power source 102 (for example, 48.0 V), a current of about 0.27 A (≈12.95 W / 48.0 V) is generated. It flows to the power receiving device.

  When the power receiving device 120 switches from the state of receiving power from the first power source 101 to the state of receiving power from the second power source 102, an inrush current of 0.23 A temporarily flows to the power receiving device 120 even after switching. Thereafter, a current of 0.27 A flows through the power receiving device 120.

  At this time, since the amount of inrush current (0.23 A) does not exceed the current limit value (400 mA) of the second power source 102, the second power source 102 does not stop power supply even if an inrush current occurs. In this way, the power source that inputs power to the conversion unit 117 can be switched from the first power source 101 to the second power source 102 while preventing the second power source 102 from stopping power feeding.

  Returning to the description of FIG. If the power consumption acquired in step S301 is greater than the first power (No in S302), it is determined whether the power consumption acquired in step S301 is greater than the second power (S304). Here, the second power is, for example, an upper limit power that can be supplied to the power receiving device 120 that requests the above-described Type 2 from the second power source 102. When the acquired power consumption is larger than the second power (Yes in S304), the control unit 116 continues the boosting by the boosting unit 109 (S305).

  In this case, the voltage (for example, 57.0V) output from the first power supply 101 and boosted by the boosting unit 109 is higher than the voltage (for example, 48.0V) from the second power supply 102. Therefore, the voltage output from the first power supply 101 and boosted by the booster 109 is applied to the converter 117 by the operations of the first output unit 112 and the second output unit 113. In this way, the power from the first power supply 101 is input to the conversion unit 117 and the load unit 118.

  In this way, when the power consumption of the power receiving apparatus 120 is larger than the power that the second power supply 102 can supply to the power receiving apparatus 120 in Type 2, the power supply from the first power supply 101 is continued. Can do. For example, when the power consumption of the power receiving apparatus 120 is larger than the amount of power that can be supplied by the PoE Type 2, power can be received from a general-purpose power source.

  Next, a case where the power consumption acquired in step S301 is greater than the first power and equal to or less than the second power (in the case of No in S304) will be described. For example, the case where the power consumption of the power receiving apparatus 120 is larger than the power that can be received by Type 1 and is equal to or lower than the power that can be received by Type 2 is applicable. That is, the case where the power supply type requested by the power receiving apparatus 120 is Type2.

  The control unit 116 instructs the delay unit 110 to output an enable signal to the boosting unit 109 after a predetermined period has elapsed (S306). Here, the predetermined period is a period from when the second detection unit 108 notifies the delay unit 110 that the voltage input from the second power supply 102 has reached a predetermined activation voltage until a predetermined time elapses. . In this embodiment, an example in which the predetermined time is 100.0 msec will be described.

  In this manner, the boosting by the boosting unit 109 is stopped after a predetermined time (for example, 100.0 msec) has elapsed since the voltage output from the second power supply 102 has reached a predetermined voltage (for example, 42.0 V). As described above, when the power consumption of the load unit 118 is larger than the predetermined power, the voltage of the boosting unit 109 is increased after a predetermined period has elapsed since the voltage input from the second power source reaches the predetermined voltage. Limit boost.

  Here, the boosting of the boosting unit 109 may be stopped and the output voltage of the boosting unit 109 does not have to drop to the output of 12.0 V of the first power supply. The control unit 116 causes the voltage output from the boosting unit 109 to be a second voltage lower than the voltage input from the second power supply 102 from the first voltage higher than the voltage input from the second power supply 102. It is sufficient to limit the boosting of the boosting unit 109.

  Further, the timing for limiting the boosting of the boosting unit 109 may be before a predetermined time elapses after the voltage output from the second power supply 102 reaches a predetermined voltage. By limiting the boosting of the boosting unit 109, the power source that inputs power to the circuits after the conversion unit 117 is switched from the first power source 101 to the second power source 102. The timing of switching the power supply may be after a predetermined time has elapsed since the voltage output from the second power supply 102 has reached a predetermined voltage.

  In the present embodiment, the power source that inputs power to the conversion unit 117 is controlled by the control unit 116 from the first power source 101 after the predetermined time has elapsed since the voltage output by the second power source 102 reaches the predetermined voltage. The power source 102 is switched.

  As described above, if a current of 400 mA or more flows from the second power source 102 before 80 msec has elapsed since the voltage input from the second power source 102 reaches a predetermined voltage (for example, 42.0 V), Stop supplying power. After 80 msec has elapsed since the voltage input from the second power supply 102 reached a predetermined voltage, the upper limit of the current output from the second power supply 102 is raised to 400 mA or more. For example, the upper limit of the current after being pulled up can be 684 mA.

  When the power consumption of the power receiving apparatus 120 is larger than the first power, an inrush current of 400 mA or more may occur after switching from the first power supply 101 to the second power supply 102. For example, when the power consumption of the power receiving device 120 is 25.0 W, a current of approximately 0.438 A (≈25.0 W / 57.0 V) is received while the voltage of the first power supply 101 is boosted and supplied. Flows to device 120. Then, an inrush current of 0.438 A is generated after switching from the first power supply 101 to the second power supply 102.

  However, according to the present embodiment, the power source that supplies power to the converter 117 is switched from the first power source 101 to the second power source 100.0 msec after the voltage output from the second power source 102 reaches a predetermined voltage. Switch to 102. That is, the power source is switched after the second power source 102 is switched to a state where power supply is not stopped even when a current of 400 mA or more flows.

  In this way, the power source that inputs power to the conversion unit 117 can be switched from the first power source 101 to the second power source 102 while preventing the second power source 102 from stopping power feeding.

  Next, operations of the first output unit 112 and the second output unit 113 will be described with reference to FIG. When the boosting of the boosting unit 109 is stopped (Yes in S310), the voltage output from the boosting unit 109 becomes lower than the voltage input from the second power supply 102. Then, the power input from the second power source 102 is output to the circuits after the converter 117 (S311). On the other hand, when the boosting of the boosting unit 109 continues (No in S310), the voltage output from the boosting unit 109 is maintained higher than the voltage input from the second power supply 102. In this case, the power output from the booster 109 is supplied to the circuits after the converter 117 (S312).

  Next, the process executed by the second detection unit 108 in step S208 is shown in FIG. When the second detection unit 108 detects that the voltage of the power input from the second power supply 102 has reached a predetermined power (for example, 42.0 V) (Yes in S401), the second detection unit 108 notifies the delay unit 110 of the notification. Do. On the other hand, when the voltage of the electric power input from the second power supply 102 has not reached the predetermined voltage, the determination process in step S401 is repeated.

  Next, the processing of the delay unit 110 in step S208 will be described using the flowchart of FIG. When receiving the above notification from the second detection unit 108 (Yes in S410), the delay unit 110 determines whether a delay instruction is received from the control unit 116 (S411). When the notification is not received from the second detection unit 108, the process of step S410 is repeated.

  If it is determined in step S411 that a delay instruction has been received from the control unit 116, an enable signal is output to the boosting unit 109 after a predetermined time (for example, 100 msec) has elapsed since the notification from the second detection unit 108 was received ( S413). On the other hand, if it is determined in step S411 that the delay instruction has not been received from the control unit 116, the enable signal is output to the boosting unit 109 without waiting for a predetermined delay time after receiving the notification from the second detection unit 108. (S414).

  Next, temporal changes in voltage and current in the power supply system shown in FIG. 1 will be described with reference to FIGS. 5 (a), (b), and (c). FIG. 5A shows a change in voltage when the second power source 102 is connected to the power receiving device 120 after the power receiving device 120 starts to receive power from the first power source 101. In the graph of FIG. 5A, the horizontal axis indicates the time axis [msec], and the vertical axis indicates the voltage [V].

  A dotted line L <b> 1 indicates a change in voltage of power input from the first power supply 101 and input to the first output unit 112. That is, the dotted line L1 indicates a change in the output voltage output from the booster 109. A solid line L2 indicates a change in the voltage output from the second power supply 102.

  First, a change (L1) in voltage input from the first power supply 101 to the first output unit 112 will be described. FIG. 5A illustrates a case where the first power supply 101 is connected to the power receiving apparatus 120 at a time of 0.0 msec. When the first detection unit 107 detects that the first power supply 101 is connected to the power receiving device 120, the first detection unit 107 causes the boosting unit 109 to start boosting. The boosting unit 109 outputs a first voltage (for example, 12.0V) output from the first power supply 101 to a voltage (for example, 57.0V) higher than a predetermined starting voltage (42.0V) of the second power supply 102. Boost up to.

  When power is supplied from the first power supply 101 to the power receiving device 120 and the second power supply 102 is not connected, the voltage boosted by the boosting unit 109 is applied to the first output unit 112. In this embodiment, a voltage input from the first power supply 101 and boosted to 57.0 V by the boosting unit 109 is applied to the first output unit 112.

  Next, when the second power supply 102 is connected to the power receiving apparatus 120, the second power supply 102 increases the output voltage after the detection process and the classification process of the power receiving apparatus 120 are completed, as will be described later for L2. As will be described later, at time T0 when the switch unit 111 determines that the voltage input from the second power supply 102 has reached a predetermined start-up voltage, the power from the first output unit 112 is supplied to the conversion unit 117 and the load unit 118. Continue to be supplied.

  Boosting by the boosting unit 109 is stopped at a time T1 when a predetermined time (for example, 100 msec) has elapsed after the voltage output from the second power supply 102 reaches the starting voltage. This process is realized by the control unit 116 controlling the delay unit 110. And the voltage applied to the 1st output part 112 from the 1st power supply 101 falls gradually, and becomes the voltage (for example, 12.0V) before a pressure | voltage rise.

  At time T2 when the voltage applied to the first output unit 112 falls below the voltage applied to the second output unit 113 (for example, 48.0 V), the power source that supplies power to the conversion unit 117 is supplied from the first power source 101. Switch to dual power supply 102.

  Thereafter, when the second power source 102 is disconnected from the power receiving device 120 by a user operation or the like, the first power source 101 resumes power feeding to the power receiving device 120. When the second detection unit 108 detects that the second power supply 102 is disconnected from the power receiving apparatus 120 at T3, the detection result is notified to the delay unit 110. When the control unit 116 receives information indicating that the second power supply 102 has been disconnected from the power receiving device 120 from the second detection unit 108, the control unit 116 causes the boosting unit 109 to resume boosting via the delay unit 110. In this case, the delay control of the boost start instruction by the delay unit 110 is not performed, and the boost of the boost unit 109 is resumed without waiting for a predetermined delay time. Due to the boosting of the boosting unit 109, the voltage of the power output from the first power supply 101 rises again to 57.0V.

  Next, a change (L2) in the voltage output from the second power supply 102 will be described. When the second power source 102 is connected to the network, the second power source 102 first performs detection processing of the power receiving device 120. The second power supply 102 detects the power receiving device 120 having a resistance having a predetermined resistance value (for example, 19.0 to 26.5 KΩ). In this embodiment, this resistor is included in the switch unit 111. In the present embodiment, the second power supply 102 detects the power receiving device 120 having a resistance of 25 KΩ.

  In the present embodiment, the second power supply 102 sequentially outputs a detection voltage V1 between 2.8V and 10V and a detection voltage V2. V1 and V2 are detection signals output from the second power supply 102 in order to detect the power receiving device 120 corresponding to the power supply procedure of the second power supply 102. In this embodiment, it is assumed that the voltage V1 is a voltage in the range of 2.81V to 6.90V. For example, V1 can be 6.0V. The voltage V2 is assumed to be a voltage in the range of 6.9V to 10.1V. For example, V2 can be 7.0V.

  The second power supply 102 measures the current value I1 when V1 is output. The second power supply 102 measures the current value I2 when V2 is output. Then, the resistance value of the resistor included in the power receiving device is measured from the value obtained by dividing the difference between I1 and I2 by the difference between V1 and V2. This measurement corresponds to detection processing of the power receiving device 120 by the second power supply 102.

  The switch unit 111 of the power receiving device 120 has the above-described resistance. When predetermined voltages V1 and V2 are output from the second power supply 102, predetermined currents I1 and I2 are output to the second power supply 102 via the communication line. To do. In this way, the power receiving device 120 is detected as the power receiving device 120 that is the power supply target of the second power supply 102. The currents I <b> 1 and I <b> 2 are a first response indicating that the power receiving device 120 receives power corresponding to the power supply procedure of the second power source 102.

  Next, the second power supply 102 classifies the detected power receiving device 120. The second power supply 102 determines the power that can be received by the power receiving device 120 according to the resistance value of the resistance of the power receiving device 120.

  In the present embodiment, an example in which the second power supply 102 outputs a voltage twice in the classification process will be described. According to the IEEE 802.3at standard, the maximum power supply power is 25.5 w, and the power supply amount can be classified into five classes according to the power supply amount.

  In this embodiment, it is assumed that the high-side (upper end) voltage of the classification voltage output from the second power supply 102 in the classification process is in the voltage range of 14.5V to 20.5V. In this embodiment, the low-side (lower end) voltage of the classification voltage output from the second power source 102 in the classification process is applied in the voltage range of 6.9V to 10.1V. The second power source 102 measures a current value when a predetermined classification voltage is output. Then, the amount of power corresponding to the measured current value is determined as the amount of power to be supplied to the power receiving device 120. The determination of the supplied power corresponds to the classification process of the power receiving device 120 by the second power source 102. The current output by the power receiving device 120 with respect to the predetermined classification voltage (classification signal) is a second response corresponding to the power required by the load connected to the power receiving device 120.

  Alternatively, the second power supply 102 may classify the power receiving device 120 by communication at the data link layer instead of the classification of the power receiving device 120 by communication at the physical layer as described above. Alternatively, the second power supply 102 may classify the power receiving apparatus 120 by using both physical layer communication and data link layer communication.

  When the classification process is completed, the second power supply 102 starts the power supply process. When the classification process is completed, the second power supply 102 increases the voltage to a voltage of 42.5 V or more and less than 57.0 V (in the case of PD Type 2). In this embodiment, it is assumed that the second power source 102 increases the voltage to 48.0V.

  Even when the voltage from the second power source 102 rises and the switch unit 111 is turned on, the voltage (for example, 48.0 V) output from the second power source 102 is applied to the first output unit 112 (for example, , 57.0V). Therefore, even if the power feeding is started, the power from the second power source 102 is not supplied to the conversion unit 117 immediately.

  When a predetermined time (for example, 100 msec) has elapsed from T0 when the voltage output from the second power supply 102 reaches a predetermined activation voltage (for example, 42.0 V), the boosting by the boosting unit 109 is stopped at T1. At time T2 when the voltage applied to the first output unit 112 falls below the voltage (eg, 48.0 V) applied to the second output unit 113, the power source that supplies power to the conversion unit 117 is the first power source 101. To the second power source 102.

  In this way, the power source that supplies power to the power receiving device 120 is changed from the first power source 101 to the second power source 102 after a predetermined time has elapsed after the voltage output from the second power source 102 reaches the predetermined voltage. Can be switched. In this way, the control unit 116 is configured so that the power source that supplies the power to be output to the load unit 118 outputs the first response (detection signal) and the second response (classification signal), and then the first power source 101. To be switched to the second power source 102.

  Next, the transition of the current limit value of the second power source 102 and the second power source 102 when the second power source 102 is connected to the power receiving device 120 while the power receiving device 120 is receiving power from the first power source 101. The transition of the current value supplied to the power receiving device 120 from FIG. 5 is shown in FIG. In the graph of FIG. 5B, the horizontal axis indicates the time axis [msec], and the vertical axis indicates the current [mA].

  A dotted line L3 in FIG. 5B indicates a change in the current limit value of the second power supply 102. In the present embodiment, L3 indicates a change in the current limit value when the power receiving apparatus 120 selects Type 2 as the power supply type in PoE of the IEEE 802.3at standard. When a current exceeding the current indicated by L3 flows from the second power source 102 to the power receiving device 120, the second power source 102 stops supplying power to the power receiving device 120.

  During the period from when the second power supply 102 is connected to the power receiving apparatus 120 until the voltage output from the second power supply 102 reaches a predetermined voltage (for example, 42.0 V), the limit value is a detection process and a classification process. Is a predetermined value determined according to each of the above. In this embodiment, the predetermined voltage is a starting voltage at which the switch unit 111 of the power receiving device 120 turns on the switch.

  When the voltage output from the second power supply 102 reaches the starting voltage, the limit value is temporarily increased. This is to temporarily raise the limit value because an inrush current temporarily flows through the power receiving device 120 when the switch unit 111 of the power receiving device 120 is turned on. This inrush current is generated because the current suddenly flows into the circuits after the switch unit 111 at the moment when the switch unit 111 is turned on.

  Subsequently, when a time of 80 msec or more has elapsed after the voltage output from the second power supply 102 reaches the starting voltage, the current limit value of the second power supply 102 is increased from 400 mA.

  A solid line L4 in FIG. 5B indicates a change in the current output from the second power supply 102. The current value during the period when the second power supply 102 is performing the detection process and the classification process of the power receiving device 120 is a current value corresponding to the voltage output by the second power supply 102 and the resistance value of the resistor held by the power receiving device 120. Become.

  Next, when the detection process and the classification process are completed and the switch unit 111 of the power receiving apparatus 120 is turned on, an inrush current is temporarily generated in the power receiving apparatus 120. A large current flows. As described above, when the voltage output from the second power supply 102 reaches the start-up voltage (42.0 V in this case), the limit value (L3) of the second power supply 102 is temporarily raised, and an inrush current is generated. Even so, the second power supply 102 does not stop power feeding. However, at this time, the voltage (57.0 V) boosted after being output from the first power supply 101 is higher than the voltage (48.0 V) output from the second power supply 102. Therefore, power is supplied from the first power supply 101 to the conversion unit 117, and power is not supplied from the second power supply 102 to the conversion unit 117. Since power is not supplied from the second power source 102, the current output from the second power source 102 is 0 mA.

  When a predetermined time (100 msec) elapses after the voltage output from the second power supply 102 reaches a predetermined start-up voltage (for example, 42.0 V), the booster 109 stops the boost in the power receiving device 120. When the boosting stops, the voltage of the power output from the first power supply 101 gradually decreases. When the voltage output from the first power supply 101 falls below the voltage of the second power supply 102 at T2, power is supplied to the converter 117. The power to be switched is switched from the first power supply 101 to the second power supply 102. Accordingly, current flows from the second power supply 102 at T2. Assuming that the power received by the power receiving device 120 is 25.0 W, the value of the current flowing through the second power source 102 is approximately 0.521 A (≈25.0 W / 48.0 V).

  In this embodiment, the second power supply 102 has a limited current value of 400 mA for a predetermined period after the voltage reaches a predetermined starting voltage. Then, after elapse of a predetermined period (for example, 80 msec), the second power supply 102 switches the limit current value to a current value larger than 400 mA. Since power supply from the second power supply 102 to the conversion unit 117 is started after the predetermined period has elapsed, the second power supply 102 can supply power without exceeding the limit current value.

  That is, according to the present embodiment, after the current limit value of the second power source 102 is raised at T4, the power source is switched from the first power source 101 to the second power source 102 at T2. Therefore, the power supply can be switched so that the value of the current flowing from the second power supply 102 does not exceed the current limit of the second power supply 102. In this way, it is possible to prevent the second power source 102 from stopping power supply when the power source is switched.

  Next, a change in the current flowing through the power receiving device 120 will be described with reference to FIG. L <b> 5 illustrated in FIG. 5C indicates a change in the value of the current flowing through the conversion unit 117 and the load unit 118 of the power receiving device 120.

  When the voltage output from the first power supply 101 is in a boosted state, the power reception device 120 is supplied with power from the first power supply 101. When the power consumed by the power receiving device 120 is 25.0 W, for example, and the voltage output from the first power supply 101 is 57.0 V, the power receiving device 120 has approximately 0.439 A (≈25.0 W / 57.0 V). Current flows.

  When the boosting by the boosting unit 109 is stopped at T1 and the voltage from the first power supply 101 starts to decrease, the value of the current flowing from the first power supply 101 to the power receiving device 120 increases in inverse proportion thereto. When the voltage from the first power supply 101 further decreases and the power supply for supplying power to the power receiving apparatus 120 is switched to the second power supply 102, a current having a value corresponding to the voltage of the second power supply 102 flows through the power receiving apparatus 120. For example, when the power consumed by the power receiving device 120 is 25.0 W and the voltage output from the second power supply 102 is 48.0 V, the power receiving device 120 has approximately 0.521 A (≈25.0 W / 48.0 V). Current flows.

  Thereafter, for example, when the second power source 102 is disconnected from the power receiving device 120 by the user, the power source that supplies power to the power receiving device 120 is switched from the second power source 102 to the first power source 101. When the power source is switched to the first power source 101, the voltage input to the power receiving device 120 temporarily decreases from the voltage (48.0V) of the second power source 102 to the voltage (12.0V) of the first power source 101. In response to this, the current flowing from the first power supply 101 to the power receiving device 120 temporarily increases. Then, when the voltage of the power output from the first power supply 101 starts to rise due to the restart of boosting by the boosting unit 109, the current flowing from the first power supply 101 to the power receiving device 120 decreases accordingly. When the boosted voltage from the first power supply 101 reaches 57.0 V, a current of approximately 0.439 A (≈25.0 W / 57.0 V) flows through the power receiving device 120.

  When the second power supply 102 is disconnected from the power receiving apparatus 120, the voltage and current from the second power supply 102 immediately drop, but the power receiving apparatus 120 is activated using the power stored in the storage unit 114 in FIG. Can continue. Here, the power stored in the storage unit 114 is the power stored in the storage unit 114 while the power receiving device 120 is receiving power from the second power supply 102. .

  As described above, according to the present embodiment, when the power receiving apparatus receives power by switching a plurality of power sources having different voltages, it is possible to prevent power supply from the power source from being stopped. Further, according to the present embodiment, the power source to which the power receiving apparatus 120 is supplied with power can be switched from the first power source 101 to the second power source 102 without exceeding the overcurrent limit of the second power source 102. In addition, according to the present embodiment, for example, even in a power receiving device that is required to be continuously activated and continuously photographed / recorded, such as a network camera, the photographing is prevented from being interrupted due to power interruption. Can do.

<Second Embodiment>
In the second embodiment, as illustrated in FIG. 6, a case where the power receiving apparatus 120 includes a processing unit 600 in addition to the components of the power receiving apparatus 120 described with reference to FIG. 1 will be described. The processing unit 600 performs control for causing each component of the power receiving apparatus 120 to execute the processing illustrated in the flowcharts of FIGS. 2 to 4. The processing unit 600 can be configured by a processor such as a CPU (Central Processing Unit), for example. When the processing unit 600 is configured as a processor, the processing unit 600 reads out and executes a program stored in the storage unit 601, thereby controlling the operation of the power supply circuit illustrated in FIG.

  The processing unit 600 receives the first signal from the first detection unit 107. This signal is a signal output by the first detection unit 107 when it is detected that the first power supply 101 is connected to the power receiving device 120. The processing unit 600 receives the second signal from the second detection unit 108. The second signal is a signal output by the second detection unit 108 when it is detected that the voltage input from the second power source 102 to the power receiving device 120 has reached a predetermined activation voltage. The processing unit 600 receives a signal from the switch unit 111. The other configuration shown in FIG. 6 is the same as that described in the first embodiment, and thus the description thereof is omitted.

  In step S <b> 201 of FIG. 2, the processing unit 600 determines whether or not power is being received from the first power supply 101 based on the detection signal from the first detection unit 107. In step S <b> 203 and step S <b> 210 of FIG. 2, the processing unit 600 determines whether the second power source 102 is connected to the power receiving device 120 based on the detection signal from the second detection unit 108. Further, in step S206 and step S212 in FIG. 2, it is determined whether power can be received from the second power source 102 based on a signal from the second detection unit. Since the other processes shown in FIGS. 2 to 4 are the same as the contents described in the first embodiment, the description thereof is omitted.

  According to the present example, similarly to the first embodiment, when the power receiving apparatus receives power by switching a plurality of power sources having different voltages, it is possible to prevent power supply from the power source from being stopped.

  In the above embodiment, an example has been described in which the power source is switched so as to receive power preferentially from the second power source 102 when the first power source 101 and the second power source 102 are connected simultaneously. However, the present invention is not limited to this. The processing unit 600 may select an appropriate power source from among the power sources that the power receiving device 120 can receive.

  The processing unit 600 determines a power source connected to the power receiving device 120 based on signals received from the first detection unit 107 and the second detection unit 108. Furthermore, the processing unit 600 determines the power supply type (for example, Type 1 and Type 2) of the second power source 102 based on the signal received from the switch unit 111.

  The processing unit 600 gives an instruction to stop the boosting by the boosting unit 109 when the load unit 118 of the power receiving device 120 switches from the state of receiving power from the first power supply 101 to the state of receiving power from the second power supply 102. For example, the processing unit 600 stops boosting by the boosting unit 109 by outputting an enable signal from the delay unit 110 to the boosting unit 109 via the second detection unit 108. By stopping the boosting of the boosting unit 109, the power source that supplies power to the load unit 118 is switched from the first power source 101 to the second power source 102 as described with reference to FIG.

  Further, the processing unit 600 starts boosting by the boosting unit 109 when the load unit 118 of the power receiving device 120 switches from the state where the load unit 118 is receiving power from the second power source 102 to the state where the load is received from the first power source 101. For example, the processing unit 600 instructs the boosting unit 109 to start boosting via the first detection unit 107. When boosting by the boosting unit 109 is started and the voltage output from the boosting unit 109 exceeds the voltage input from the second power supply 102, the power supply that supplies power to the load unit 118 is supplied from the second power supply 102 to the first power supply 101. Switch to

  Furthermore, the processing unit 600 can switch the power supply type of the second power source 102 by controlling the switch unit 111.

  In this manner, it is possible to select an appropriate power source from among the power sources that can be received by the power receiving apparatus 120 and to supply power to the load unit 118.

  Thus, the present invention can also be applied to the power receiving device 120 whose power consumption varies depending on the situation. For example, in a network camera, in addition to the camera body, power consumption fluctuates in accordance with usage conditions of sensors such as human sensors, lighting devices, driving units for changing the imaging direction of the camera, and heaters. Even when switching between receiving power from the first power supply 101 or receiving power from the second power supply 102 in accordance with such fluctuations in power consumption, according to the present invention, the power supply from the power supply is not interrupted. Can be switched. Alternatively, the processing unit 600 may perform control for switching the power supply in accordance with an instruction from the user. The present invention is not limited to these specific embodiments, and some of the above-described embodiments may be combined as appropriate. For example, the control unit 116 may perform part or all of the processing of the processing unit 600 described above.

101 First power source 102 Second power source 120 Power receiving device 109 Booster unit 110 Delay unit 112 First output unit 113 Second output unit 116 Control unit

Claims (15)

Power receiving means for receiving power from a first power source and receiving power via a communication line from a second power source for limiting a predetermined amount of current to be output;
Output means for outputting the power received by the power receiving means to a load;
The power source that supplies the power output from the output means to the load is supplied from the first power source after the predetermined period has elapsed since the voltage input from the second power source has reached a predetermined voltage. And a control means for controlling to switch to the second power source. Boosting means for boosting a voltage input from the first power supply and outputting the boosted voltage to the output means;
The control means changes the voltage output from the boosting means from a first voltage higher than a voltage input from the second power supply to a second voltage lower than a voltage input from the second power supply. The boosting of the boosting means is limited so that the power supply that supplies the power output from the output means to the load is switched from the first power supply to the second power supply after the predetermined period has elapsed. The power receiving device according to claim 1, wherein the power receiving device is controlled as follows.   2. The switch unit according to claim 1, further comprising: a switch unit that allows the power from the second power source to be supplied to the output unit when the voltage input from the second power source reaches the predetermined voltage. Power receiving device. Boosting means for boosting a voltage input from the first power supply and outputting the boosted voltage to the output means;
When the power consumption of the load is greater than a predetermined power, the control means, after the predetermined period has elapsed since the voltage input from the second power source reaches the predetermined voltage, Boosting of the boosting means is limited, and when the power consumption of the load is equal to or lower than the predetermined power, the voltage input from the second power source reaches the predetermined voltage and the predetermined time period is within the predetermined period. The power receiving device according to claim 1, wherein boosting of the boosting unit is limited. In response to the detection signal output from the second power source, a first response indicating that the power receiving device receives power corresponding to the power supply procedure of the second power source is sent via the communication line to the second response. The second response corresponding to the power required by the load connected to the power receiving device is output via the communication line to the classification signal output from the second power source and output from the second power source. Response means for outputting to the power source of
The control means includes: a power supply that supplies power output from the output means to the load; and after the response means outputs the first response and the second response, from the first power supply to the first power supply. 2. The power receiving device according to claim 1, wherein the power receiving device is controlled to be switched to a power source of 2. Having generating means for generating a captured image;
The power receiving apparatus according to claim 1, wherein the output unit outputs power to the generation unit as the load. A second power source that limits the amount of current to be output for a predetermined period;
Power receiving means for receiving power from a first power source and receiving power from the second power source via a communication line;
Output means for outputting the power received by the power receiving means to a load;
The power source that supplies the power output from the output means to the load is supplied from the first power source after the predetermined period has elapsed since the voltage input from the second power source has reached a predetermined voltage. And a control means for controlling to switch to the second power source. A first power receiving step for receiving power from a first power source;
A second power receiving step of receiving power via a communication line from a second power source that limits the amount of current to be output for a predetermined period;
An output step in which the output means outputs the received power to the load; and
In the output step, a power source that supplies power to be output to the load is supplied from the first power source after the predetermined period has elapsed since the voltage input from the second power source has reached a predetermined voltage. And a control step of controlling to switch to the second power source. The boosting means has a boosting step of boosting the voltage input from the first power source and outputting the boosted voltage to the output means;
In the control step, the voltage output from the boosting unit is changed from a first voltage higher than a voltage input from the second power supply to a second voltage lower than a voltage input from the second power supply. The boosting of the boosting means is limited so that the power supply that supplies the power output from the output means to the load is switched from the first power supply to the second power supply after the predetermined period has elapsed. The control method according to claim 8, wherein control is performed as follows. The boosting means has a boosting step of boosting the voltage input from the first power source and outputting the boosted voltage to the output means;
In the control step, when the power consumption of the load is larger than a predetermined power, the voltage input from the second power source reaches the predetermined voltage, and after the predetermined period has elapsed, Boosting of the boosting means is limited, and when the power consumption of the load is equal to or lower than the predetermined power, the voltage input from the second power source reaches the predetermined voltage and the predetermined time period is within the predetermined period. 9. The control method according to claim 8, wherein boosting of the boosting means is limited. In response to the detection signal output from the second power source, a first response indicating that the power receiving device receives power corresponding to the power supply procedure of the second power source is sent via the communication line to the second response. A first response step of outputting to a power source of
A second response corresponding to the power required by the load connected to the power receiving device is output to the second power source via the communication line in response to the classification signal output from the second power source. Two response steps;
In the control step, the power source that supplies the power to be output to the load in the output step outputs the first response and the second response, and then the first power source to the second power source. The control method according to claim 8, wherein the control is performed so as to be switched. Power is received from the first power source and the amount of current to be output is limited for a predetermined period. The power receiving unit receives power from the second power source via the communication line, and outputs the power received by the power receiving unit to the load. A computer having output means for
The power source that supplies the power output from the output means to the load is supplied from the first power source after the predetermined period has elapsed since the voltage input from the second power source has reached a predetermined voltage. A program for executing a control procedure for controlling to switch to the second power source. In the computer,
Executing a boosting procedure for controlling the boosting means to boost the voltage input from the first power supply and output the boosted voltage to the output means;
In the control procedure, the voltage output from the booster is changed from a first voltage higher than a voltage input from the second power supply to a second voltage lower than a voltage input from the second power supply. The boosting of the boosting means is limited so that the power supply that supplies the power output from the output means to the load is controlled so that the first power supply is switched to the second power supply. The program described in. In the computer,
Executing a boosting procedure for controlling the boosting means to boost the voltage input from the first power supply and output the boosted voltage to the output means;
In the control procedure, when the power consumption of the load is greater than a predetermined power, the voltage input from the second power source reaches the predetermined voltage, and after the predetermined period has elapsed, Boosting of the boosting means is limited, and when the power consumption of the load is equal to or lower than the predetermined power, the voltage input from the second power source reaches the predetermined voltage and the predetermined time period is within the predetermined period. The program according to claim 12, which causes the computer to execute processing for limiting boosting by the boosting unit. In the computer,
In response to the detection signal output from the second power source, a first response indicating that the power receiving device receives power corresponding to the power supply procedure of the second power source is sent via the communication line to the second response. A first response procedure to be output to the power source and a classification signal output from the second power source, a second response corresponding to the power required by the load connected to the power receiving device is sent to the communication line. A second response procedure for outputting to the second power source via
In the control procedure, after the power source that supplies the power output from the output means to the load outputs the first response and the second response, the first power source changes to the second power source. The program according to claim 12 for causing the computer to execute a process of controlling to switch.

Images