JP2019092315A - Power supply device and method for controlling the same - Google Patents

Abstract

To provide a power supply device allowing stable power supply output at a low cost.SOLUTION: A power supply device for receiving power from a first power supply and a second power supply and supplying the power to a load unit comprises: voltage conversion means for converting a first voltage from the first power supply and outputting a first conversion voltage; control means for controlling the first conversion voltage by the voltage conversion means; and supply means for supplying an output from a junction unit to the load unit. The junction unit connects an output of a second voltage from the second power supply and an output of the first conversion voltage from the voltage conversion means. The control means determines the first conversion voltage on the basis of whether to prioritize the first power supply or the second power supply and receive power.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply device that switches and uses a power supply of a supply source.

  As a power supply of peripheral devices connected to a LAN (Local Area Network) cable, a PoE (Power over Ethernet (registered trademark)) power supply defined by the IEEE 802.3 at standard is known. In an imaging apparatus such as a network camera, many products compatible with this PoE power supply are widely used to improve installation. In addition, peripheral devices compatible with PoE power can receive power from a general-purpose power supply either for backup when power supply from the PoE power supply is stopped or to avoid the power limit according to the standard for the PoE power supply. Exists. In particular, since the power source to be used preferentially depends on the load condition of the imaging device, the installation environment, and the like, the demand for a power receiving device capable of selecting the power source of the supply source is high.

  By the way, in the power supply apparatus used by switching between the PoE power supply and the general-purpose power supply according to the situation, when the power supply to the peripheral device is stopped when switching the power supply source, the peripheral device stops its operation. A restart will occur. As a result, for example, in an image pickup apparatus used as a surveillance camera, a period in which it can not be monitored occurs, and there is a possibility that an image of an evidence scene may be missed. Therefore, there has been proposed a power supply device capable of seamlessly switching the power supply source without stopping the power supply.

  In Patent Document 1, when switching from a general-purpose power supply to a PoE power supply, sufficient charge is stored in a charge storage unit such as an electrolytic capacitor in order to prevent power supply interruption due to inrush current from the PoE power supply to the power supply device. It discloses the technology of switching after detection. Further, Patent Document 2 discloses a configuration in which a booster circuit is provided at an input portion from a general-purpose power supply in order to prevent power supply interruption due to a rush current from a PoE power supply to a power supply device.

JP, 2012-95502, A JP, 2015-192506, A

  However, in patent document 1, since it is necessary to respond | correspond to the wide input voltage from a general purpose power supply (12 V etc.) and PoE power supply (37 V-57 V), it is necessary to enlarge the input capacity of a voltage conversion circuit. Moreover, in patent document 2, the general purpose power supply of high output electric power which considered the voltage conversion loss resulting from a voltage booster circuit is needed. As a result, there is a problem that the cost of the power supply device increases.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a power supply device capable of stable power output at low cost.

  In order to solve the above-mentioned subject, the power supply device concerning the present invention is provided with the following composition. That is, the power supply apparatus which receives power from the first power supply and the second power supply and provides power to the load unit converts the first voltage from the first power supply and outputs the first converted voltage Control means for controlling the first converted voltage by the voltage conversion means, an output of a second voltage from the second power supply, and an output of the first converted voltage from the voltage conversion means. Providing means for providing an output from the connected junction to the load unit, the control means based on which of the first power supply and the second power supply is to be prioritized to receive power. The first conversion voltage is determined.

  According to the present invention, it is possible to provide a power supply device capable of stable power output at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the system in 1st Embodiment. It is a block diagram showing composition of an imaging device containing a power supply device concerning a 1st embodiment. It is a flowchart which shows the operation | movement at the time of switching the supply source power supply in 1st Embodiment. It is a figure explaining the output voltage of insulation type DCDC. It is a block diagram which shows the structure of the imaging device containing the power supply device which concerns on 2nd Embodiment. It is a flowchart which shows the operation | movement at the time of switching the supply source power supply in 2nd Embodiment. It is a figure which shows the whole structure of the system in 3rd Embodiment. It is a block diagram which shows the structure of the power receiving apparatus (PD) containing the power supply device which concerns on 3rd Embodiment. It is a flowchart which shows the operation | movement at the time of the power supply device stop in 3rd Embodiment. It is a flow chart which shows operation at the time of power supply device starting in a 3rd embodiment.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. The following embodiment is merely an example and is not intended to limit the scope of the present invention.

First Embodiment
A network camera will be described below as an example of the first embodiment of the power supply device according to the present invention.

<System configuration>
FIG. 1 is a diagram showing an overall configuration of a system in the first embodiment. The imaging device 1000 is a network camera including a power supply device that captures a moving image within a predetermined angle of view. The imaging device 1000 is an example of a device in which the power supply device according to the first embodiment and a load device operated by the output voltage of the power supply device are integrated. The load device may be any device, and the power supply device and the load device may be separate components.

  The client device 2000 is an external device. The imaging apparatus 1000 and the client apparatus 2000 are communicably connected to each other via the network 1500. In particular, the imaging apparatus 1000 is configured to receive power supply from a power supply apparatus (PSE: Power Sourcing Equipment) 1100 that is a network device and compliant with the PoE standard.

  The imaging apparatus 1000 has an input unit for inputting information from an external apparatus including the client apparatus 2000. The client apparatus 2000 can transmit various control commands to the imaging apparatus 1000. The control command includes, for example, a command such as an instruction to change various parameter settings in the imaging apparatus 1000. Further, when receiving the control command, the imaging apparatus 1000 transmits a response to the control command to the client apparatus 2000.

  The network 1500 includes, for example, a plurality of network devices (routers, switches, and the like), cables, and the like compliant with the Ethernet (registered trademark) standard. The PSE 1100 connected to the network 1500 can perform data communication with the imaging device 1000 which is a power receiving device (PD: Power Device) and supply power to the imaging device 1000 by superimposing power supply power on the LAN cable. ing.

  The imaging device 1000 is configured to be able to receive power from the PSE 1100, and is also connected to be able to receive power from the general-purpose power supply device 1200. Here, the general-purpose power supply device 1200 is assumed to be an AC adapter that outputs a DC power source obtained by ACDC conversion from a commercial AC power source, but may be another power source such as a battery, for example. .

  FIG. 2 is a block diagram showing a configuration of an imaging device including the power supply device according to the first embodiment. In particular, the detailed structure of the power supply related portion in the imaging apparatus 1000 is shown.

  The imaging apparatus 1000 can be classified into three major blocks of the power supply unit 101, the load unit 201, and the control unit 301. The power supply unit 101 generates a predetermined output voltage from a power supply input from the outside. The load unit 201 is a predetermined functional unit that operates using the output of the power supply unit 101 as a power supply. The control unit 301 centrally controls the entire imaging apparatus 1000 including the power supply unit 101 and the load unit 201. The power supply device according to the first embodiment corresponds to the configurations of the power supply unit 101 and the control unit 301.

  The load unit 201 is a camera here, and an optical image of a subject passes through an optical lens, an optical filter, and the like provided in the load unit 201 and enters an imaging device such as a CCD or a CMOS sensor. Then, the subject image formed on the imaging device is converted into image data. However, as described above, the load unit 201 is not limited to the camera as long as the load is operated using the output voltage of the power supply unit 101.

  In the control unit 301, a system controller 302 includes a CPU, controls the respective components of the imaging apparatus 1000 in an integrated manner, and sets various parameters. Also, the CPU of the system controller 302 executes a program stored in the memory 305. The memory 305 is used not only as a storage area for programs executed by the CPU but also as a work area for a program being executed, a storage area for various parameters, a storage area for output data from the load unit 201, and the like.

  The communication unit 304 is used when receiving each control command from the client apparatus 2000, and when transmitting a response to each control command to the client apparatus 2000, and operates according to an instruction of the system controller 302.

  The priority order determination unit 303 determines which power supply to select based on priority power supply settings received from the client apparatus 2000 via the network 1500 and priority power supply settings stored in advance in the memory 305. Then, the system controller 302 is notified of the determination result. Although the priority determination unit 303 is configured to receive an instruction from the client apparatus 2000 via the network here, the present invention is not limited to this. For example, the priority power source setting may be determined based on the state of an input switch (not shown) disposed in the imaging apparatus 1000.

  In the power supply unit 101, the power received from the PSE 1100 which is the first power supply is connected to the isolated DCDC 102. This is because in the PoE standard, PD requires electrical isolation between all external conductors including frame ground. The resistors R1 and R2 connected in series are connected to the output of the isolated DCDC 102. The partial pressure between the resistors R1 and R2 is input to the feedback (FB) terminal of the isolated DCDC 102. The output voltage Vout from the output portion of the isolated DCDC 102, which is the first conversion voltage, is set as follows by the resistors R1 and R2 and the threshold value Vth of the FB terminal.

Vout = Vth × (1 + R1 / R2) (1)
Here, the resistor R2 is a variable resistor, and the system controller 302 can adjust the resistance value. Therefore, the output voltage Vout can be adjusted by adjusting the resistance value of the resistor R2. However, the adjustment of the output voltage of the isolated DCDC 102 is not limited to the method described above. For example, the output voltage may be adjusted by outputting an analog voltage directly from the system controller 302 to the FB terminal.

  The output of the isolated DCDC 102 is connected to the anode side of the diode D2. In addition, a general power supply, which is a second power supply as another power supply, is connected to the anode side of the diode D1. The cathodes of the diode D1 and the diode D2 are connected to each other to form a junction of diode OR connection. As a result, the higher one of the output voltage of the general-purpose power supply and the output voltage of the isolated DCDC 102 is input (supplied) to the non-insulated DCDC 103.

  The non-insulated DCDC 103 converts the voltage input from the diode OR connection into a voltage required by the load unit 201 and the control unit 301. Although only one non-insulated DCDC 103 is illustrated here, a plurality of the non-insulated DCDCs 103 may be arranged according to the type of voltage required by the load unit 201 and the control unit 301. The non-insulated DCDC 103 does not limit the voltage conversion method, and may be, for example, an LDO regulator.

  In the PoE standard, the PoE power supply stops supplying power when the current value continues to be less than a predetermined threshold. Therefore, by connecting the output portion of the isolated DCDC 102 to GND via the resistor R3, the amount of current does not fall below a predetermined amount. Thus, even when voltage conversion of the power supply unit 101 is being performed by power supply using a general-purpose power supply, power supply using the PoE power supply is performed. Therefore, even when the general-purpose power supply suddenly stops, it is possible to instantly switch to voltage conversion by the PoE power supply.

<Operation of device>
FIG. 3 is a flow chart showing an operation at the time of switching the power supply source in the first embodiment. Specifically, processing relating to power supply priority determination and output voltage adjustment of the isolated DCDC 102 is shown. These processes are executed by the priority determination unit 303 that has received an instruction from the system controller 302 or the system controller 302.

  In S101, the priority determination unit 303 confirms whether or not there is an instruction input (user setting) of the priority power supply from the client apparatus 2000. If an instruction input from the client apparatus 2000 is received, the process proceeds to step S102, and if no, the process proceeds to step S103. In S102, the priority determination unit 303 reads user settings. On the other hand, in S103, the priority determination unit 303 reads the setting value stored in the memory 305.

  In step S104, the priority determination unit 303 determines whether the setting value read in step S102 or S103 preferentially selects the PoE power supply or selects the general-purpose power supply. When priority is given to PoE, the process proceeds to step S105, and when priority is given to the general-purpose power supply, the process proceeds to step S106.

  In S105, the system controller 302 determines the value of the resistor R2 to the resistance value “R2-” stored in the memory 305 in order to set the output voltage of the isolated DCDC 102 to a predetermined voltage. On the other hand, in S106, the system controller 302 sets the value of the resistor R2 to the resistance value “R2 +” stored in the memory 305 in order to set the output voltage of the isolated DCDC 102 to a predetermined voltage.

  FIG. 4 is a diagram for explaining the output voltage of the isolated DCDC. The output voltage (voltage V02 and voltage V04) of the insulation type DCDC 102 set based on the determination result of the power supply priority in the process of the flowchart of FIG. 3 will be described in detail with reference to FIG.

  The voltage V03 indicates the range of the output voltage of the general-purpose power supply device 1200 (voltage range permitted by the power supply device). The voltage V 02 and the voltage V 04 respectively indicate the output voltage of the isolated DCDC 102. The voltage V 01 and the voltage V 05 respectively indicate the upper limit value and the lower limit value of the input voltage range of the non-insulated DCDC 103.

  Here, it is assumed that V03 is set to 12 V ± 10% (10.8 V to 13.2 V). Further, it is assumed that the upper limit value V05 of the input voltage range necessary for outputting the predetermined output voltage of the non-insulated DCDC 103 is 20 V, and the lower limit value V01 is 8 V. In addition, these voltage values are an example and are not limited only to the numerical value of a statement.

  As described above, when it is determined that the PoE power supply is to be preferentially used (Yes in S104), the system controller 302 sets the value of the resistor R2 to the resistance value “R2-” stored in the memory 305. Here, the resistance value “R2−” is a value set such that the output voltage of the insulating DCDC 102 becomes an output voltage V04 higher than the voltage V03, and is stored in advance in the memory 305. Here, the output voltage V04 is set to 15V. Thus, the power input to the non-insulated DCDC 103 via the diode OR connection is the power from the PoE power supply. That is, power from the PoE power supply is supplied to the imaging apparatus 1000 to operate.

  In this situation, when the power from the PoE power supply is cut off due to the failure of PSE 1100 or the use condition of PSE 1100, the output voltage V04 of isolated DCDC 102 is lowered. Then, when the output voltage V04 decreases and the voltage V03 of the general-purpose power supply becomes higher, the power input to the non-insulated DCDC 103 via the diode OR connection automatically becomes the power from the general-purpose power supply.

  Similarly, when it is determined that the general-purpose power supply is to be preferentially used (No in S104), the system controller 302 sets the value of the resistor R2 to the resistance value “R2 +” stored in the memory 305. Here, the resistance value “R2 +” is a value set such that the output voltage of the insulating DCDC 102 is an output voltage V02 lower than the voltage V03, and is stored in advance in the memory 305. Here, the output voltage V02 is set to 10V. Thus, the power input to the non-insulated DCDC 103 via the diode OR connection is the power from the general-purpose power supply. That is, power from the general-purpose power supply is supplied to the imaging apparatus 1000 to operate.

  In this situation, when the universal power supply 1200 fails and power from the universal power supply is cut off, the output voltage V03 of the isolated DCDC 102 is lowered. Then, when the output voltage V03 decreases and the output voltage V02 of the isolated DCDC 102 becomes higher, the power input to the non-insulated DCDC 103 through the diode OR connection is automatically the power from the isolated DCDC 102. It becomes.

  As described above, according to the first embodiment, one power source designated by the user can be preferentially selected and received. In addition, even when the selected power supply is stopped, it is possible to smoothly switch to the other power supply. That is, within the input voltage range (voltage V01 to voltage V05) of the non-insulated DCDC 103, it is possible to automatically switch the power from the isolated DCDC 102 (power from the PoE power supply) and the power from the general-purpose power supply.

  Furthermore, the voltage can be converted by the isolated DCDC 102 only for the PoE power supply, and a power supply switching configuration can be made using diode-OR connection of the output (secondary side) of the isolated DCDC 102 and the output of the general-purpose power supply. That is, the power source switching configuration can be simplified as compared with the conventional power source switching configuration in which switching is performed on the input side (primary side) of the isolated DCDC 102.

  In addition, since the general-purpose power supply does not go through the isolated DCDC, the power conversion loss is small. Therefore, it is also possible to reduce the required specification for the general-purpose power supply device 1200. Therefore, it is possible to provide a power supply device at low cost.

  In the above description, the PoE power supply has been described as an example, so that the voltage conversion is performed using the insulation type DCDC. However, the present invention is not limited to the combination of the PoE power supply and the insulation type DCDC.

Second Embodiment
In the second embodiment, another form of the power supply device will be described. Specifically, an embodiment will be described in which the voltage from the general-purpose power supply is monitored to switch the power supply source.

<Device configuration>
FIG. 5 is a block diagram showing a configuration of an imaging device including the power supply device according to the second embodiment. In FIG. 5, a voltage detection unit 104 for detecting a voltage from a general-purpose power supply is added to the power supply unit 101 shown in the first embodiment (FIG. 2). The system controller 302 adjusts the value of the resistor R2 in accordance with the monitoring result of the general-purpose power supply voltage and the result of the priority determination unit 303. The method of adjusting the resistor R2 will be described later with reference to FIG.

<Operation of device>
FIG. 6 is a flow chart showing an operation at the time of switching the power supply source in the second embodiment. Specifically, processing relating to power supply priority determination and output voltage adjustment of the isolated DCDC 102 is shown. These processes are executed by the priority determination unit 303 or the voltage detection unit 104 that has received an instruction from the system controller 302 or the system controller 302.

  In step S201, the priority order determination unit 303 confirms whether or not designation of the priority power supply (user setting) has been performed from the client apparatus 2000. If there is a designation from the client apparatus 2000, the processing proceeds to S202, and if not, the processing proceeds to S203. In S202, the priority determination unit 303 reads user settings. On the other hand, in S203, the priority determination unit 303 reads the setting value stored in the memory 305.

  In S204, the voltage detection unit 104 detects the voltage of the general-purpose power supply, and in S205, the system controller 302 calculates a reference resistance value R2ref that makes the output voltage of the isolated DCDC 102 equal to the detected general-purpose power supply voltage.

  In step S206, the priority determination unit 303 determines whether the setting value read in step S202 or S203 preferentially selects the PoE power supply or selects the general-purpose power supply. When priority is given to PoE, the processing proceeds to step S207, and when priority is given to the general-purpose power supply, the processing proceeds to step S208.

  In S207, the system controller 302 sets the value of the resistor R2 to "R2-" smaller than the reference resistance value R2ref in order to set the output voltage of the isolated DCDC 102 to a predetermined voltage. For example, when the general-purpose power supply voltage detected in S204 is 12 V, the resistance value "R2-" is set such that the output voltage of the insulating DCDC 102 is 13 V.

  On the other hand, in S208, the system controller 302 sets the value of the resistor R2 to “R2 +” which is larger than the reference resistance value R2ref in order to set the output voltage of the isolated DCDC 102 to a predetermined voltage. For example, when the general-purpose power supply voltage detected in S204 is 12 V, the resistance value "R2 +" is set such that the output voltage of the insulation type DCDC 102 is 11 V.

  As described above, according to the second embodiment, according to the first embodiment, one power source designated by the user can be preferentially selected and received. In addition, even when the selected power supply is stopped, it is possible to smoothly switch to the other power supply.

  Further, in the first embodiment described above, it has been necessary to set the output voltage of the isolated DCDC 102 outside the range of 12 V ± 10% of the input voltage allowed for the general-purpose power supply device 1200. Therefore, the input-output voltage difference of non-insulation type DCDC103 becomes large, and voltage conversion efficiency may fall. In the second embodiment, by setting the resistor R2 in accordance with the monitoring result of the general-purpose power supply voltage, the input / output voltage difference can be minimized, and a decrease in voltage conversion efficiency can be suppressed.

Third Embodiment
In the third embodiment, in a power receiving apparatus that receives power by PoE power feeding, an embodiment will be described in which the time taken to restart the power receiving apparatus can be shortened.

Prerequisite technology
In PoE power feeding, when the power receiving device receives power from the power feeding device, the following processing is performed between the power feeding device and the power receiving device. First, as detection, the power feeding device outputs a predetermined voltage to the power receiving device and measures the resistance value of the power receiving device. Then, if the measured resistance value is within the predetermined range, the power feeding device determines that the power receiving device is present. Subsequently, the power supply apparatus performs classification, and confirms the power class required by the power receiving apparatus. Then, the power feeding device starts supplying power to the power receiving device when it is determined that the power feeding device itself can supply the checked power.

  While PoE feeding is effective, the feeding device performs processing of detecting disconnection of the power receiving device, and shuts off PoE feeding when disconnection is detected. Specifically, if a predetermined current Iport (10 mA) or more does not flow for a predetermined time Tmps (60 ms) or more in a period Tmpdo (300 ms to 400 ms), it is determined that the power receiving device is disconnected, and the power supply is cut off. Do.

  As described above, in order to receive power by PoE power feeding, it is necessary to satisfy the start-up procedure and operating conditions defined by the standard (IEEE 802.3 at). Therefore, when restarting the power receiving apparatus, it is necessary to perform PoE power detection and classification again. In addition, it will take several minutes to carry out a power negotiation to negotiate whether the power supply apparatus can supply the desired power.

  In particular, in an imaging apparatus such as a network camera, if the time taken to restart the system is long, problems such as missing important site photography may occur without the purpose of the original device being fulfilled.

<System configuration>
FIG. 7 is a diagram showing an entire configuration of a system in the third embodiment. The power supply apparatus (PSE) 3000 is a power supply apparatus compatible with PoE power supply, and here a PoE compatible HUB is assumed, but it may be another network device. Although the power receiving device (PD) 3001 is assumed to be a network camera here, it may be another electronic device. The power feeding device 3000 and the power receiving device 3001 are connected via a LAN cable 3002. The power feeding device 3000 can perform data communication with the power receiving device 3001 and supply power to the power receiving device 3001. The power supply device 3000 operates by receiving power from an external power supply 3003 such as a commercial AC power supply or a battery.

  There are two power transmission and reception methods by PoE. One is a method for superimposing power on a communication line in the LAN cable 3002, and the other is a method for transmitting and receiving power using a spare line different from the communication line. The power reception device 3001 can cope with either method using a circuit described later.

  FIG. 8 is a block diagram showing a configuration of a power reception device 3001 including the power supply device according to the third embodiment.

  A connector 401 indicates a connector for connecting the LAN cable 3002. The pulse transformer 402 separates the communication data and the power when the power is superimposed on the communication line. The separated power source is input to the PD controller 405 via the rectifying diode 404. The pulse transformer 402 is connected to the control unit 407, and the separated communication data is transmitted to the control unit 407. Thereby, the control unit 407 can communicate with the power feeding device 3000.

  In addition, when power is received via a spare line other than the communication line, the signal is input to the PD controller 405 via the rectifying diode 403. At this time, the pulse transformer 402 plays a role of merely transmitting communication data. Communication data transmitted from the communication line is transmitted to the control unit 407.

  The PD controller 405 is a controller that executes a power supply sequence defined by the IEEE 802.3 at standard, and includes a detection resistor, a power classification resistor, a power supply noise filter, and the like. That is, the PD controller 405 confirms whether the power supply from the power supply apparatus 1000 can be supplied. An output voltage from the PD controller 405 is converted by the voltage conversion unit 406 into a voltage suitable for the control unit 407 and the load unit 408. In FIG. 8, the voltage conversion unit 406 is illustrated as one block for the sake of simplicity, but a plurality of voltage conversion units may be present depending on the type of voltage desired by the control unit 407 and the load unit 408.

  The voltage conversion unit 406 monitors its own input voltage via the resistor 409, and generates an output voltage when it detects that the input voltage is equal to or higher than a predetermined value. The control unit 407 performs various controls including control of the load unit 408 and power negotiation with the power supply apparatus 3000 based on a program stored in a memory (not shown). Further, the control unit 407 can reduce the voltage of the voltage monitoring (EN) terminal of the voltage conversion unit 406 by outputting a predetermined voltage to the transistor 410. By reducing the voltage at the EN terminal and stopping the output of the voltage conversion unit 406, power supply restart can be performed on the control unit 407 and the load unit 408.

  Here, although the transistor 410 is assumed to be a digital transistor, it is not limited thereto. For example, the control unit 407 may be configured as a FET or an open collector output general-purpose logic IC or the like, or the control unit 407 itself may include the function of the transistor 410 and output as an open collector output.

  Further, the control unit 407 can transmit an operation start signal (START) and an operation stop signal (STOP) to the signal latch unit 411. In addition, an operation confirmation signal (DET) for confirming the operation state of the power consumption unit 412 can be received.

  Here, it is assumed that the signal latch unit 411 is configured by a D flip flop so as to enable signal holding. When the operation start signal (START) is output from the control unit 407, the signal latch unit 411 detects the rising edge of the CLK terminal, and the Q terminal changes to Hi output. The Q terminal is connected to the transistor 413, and when the Q terminal is a Hi output, the collector current flows through the transistor 413, and the power consumption unit 412 consumes the power.

  Here, the power consumption unit 412 is a resistor and 3.3 kΩ so that power consumption exceeding the current Iport (10 mA) for not blocking the PoE feeding is generated with respect to the PoE feeding voltage (37 V to 57 V). Is selected. However, the power consumption unit 412 may be, for example, a drive circuit such as an LED or a fan through which a current equal to or greater than that flows.

  Further, by outputting the voltage on the GND side of the power consumption unit 412 to the control unit 407, the control unit 407 can check whether the power consumption unit 412 is consuming power. That is, when the power consumption unit 412 does not consume power, the Hi signal is output to the DET terminal of the control unit 407, and when it is consumed, the Low signal is output.

  In addition, when the control unit 407 outputs the operation stop signal Hi from the STOP terminal to the signal latch unit 411, the output of the Q terminal of the signal latch unit 411 is reset to Low, and the power consumption unit 412 consumes no power. . As described above, when the signal latch unit 411 detects the rising edge of the operation start signal of the control unit 407, the signal latch unit 411 can continue operating the current consumption unit 412 until the operation stop signal is input from the control unit 407. There is. Here, it is assumed that the signal latch unit 411 is configured by a D flip flop, but it is not limited to this. For example, a circuit having a similar function may be provided using a transistor or the like, or the same function may be mounted by a microcomputer.

  Here, the load unit 408 is assumed to be a network camera, and more specifically, a lens barrel constituting an network camera, an imaging sensor, an image processing engine, a cooling fan, etc. It is not a thing.

<Operation of device>
Subsequently, with reference to FIGS. 9 and 10, an operation of the control unit 407 in the case of restarting the power receiving device 3001 will be described. FIG. 9 is a flowchart showing an operation at the time of stopping the power supply device in the third embodiment. On the other hand, FIG. 10 is a flowchart showing an operation at the time of power supply device startup in the third embodiment.

  The flowchart in FIG. 9 is started when the control unit 407 detects a power supply stop request for the power receiving device 3001.

  In S301, the control unit 407 stops the operation of the load unit 408. In step S302, the control unit 407 determines whether there is a PoE power supply cutoff request. If the power supply restart is to be performed without interrupting the PoE power supply, the process proceeds to step S303. If not, the process proceeds to step S305.

  In S303, the control unit 407 changes the output of the STOP terminal to Low, and cancels the reset of the signal latch unit 411. In S304, the control unit 407 sets the output of the START terminal to Hi. Thereby, the signal latch unit 411 detects a signal rising edge of the START terminal, the output of the Q terminal of the signal latch unit 411 becomes Hi, and the power consumption unit 412 starts power consumption.

  In S305, the control unit 407 sets the PDOWN terminal to Hi. As a result, the EN terminal of the voltage conversion unit 406 becomes Low, the operation of the voltage conversion unit 406 is stopped, and the power supply to the control unit 407 and the load unit 408 is stopped. When the power supply to the control unit 407 is stopped, the output of the PDOWN terminal gradually becomes Low, and the voltage applied to the EN terminal of the voltage conversion unit 406 rises. When the voltage at the EN terminal exceeds a predetermined voltage, power supply to the control unit 407 and the load unit 408 is resumed.

  When the power supply to the control unit 407 is resumed, the control unit 407 performs a predetermined initialization process and the like, and then starts an operation of activating the power supply device.

  In S401, the control unit 407 detects an input signal of the DET terminal. If the signal level is low, the process proceeds to step S402. If the signal level is high, the process proceeds to step S404.

  In step S404, the control unit 407 performs, for the power supply apparatus 3000, the power negotiation defined in the PoE standard. This is because when the signal level is Hi, the control unit 407 recognizes that it is the activation timing by PoE feeding. Note that the start is a start due to the connection of the LAN cable 3002 or a start after PoE feeding is restored when there is a PoE cutoff request in S302 described above.

  By the way, according to the IEEE 802.3 at standard, 0 to 13 W of power consumption of the power receiving device is classified as “TYPE 1”, 13 to 25.5 W is classified as “TYPE 2”, and power for judging whether necessary power can be received from the power feeding device The negotiation method is different. Here, the power consumption of the load unit 408 is assumed to be TYPE 2 of 15 W. In the power receiving apparatus of TYPE 2, there are the following two methods for determining whether or not desired power can be received from the power supply apparatus 3000.

  When 2-event classification is performed in the power feeding device 3000, the PD controller 405 transmits, to the control unit 407, a “T2P signal” indicating that the power feeding device 3000 is a power feeding device conforming to TYPE2. When the control unit 407 receives the T2P signal, the control unit 407 determines that the load unit 408 can be activated, and proceeds to step S405. In S405, the control unit 407 activates the load unit 408.

  On the other hand, when one event classification is performed in the power feeding device 3000, the PD controller 405 does not output the T2P signal. In this case, the power receiving apparatus 3001 communicates with the power feeding apparatus 3000, and negotiates whether the desired power can be supplied. Note that since the power receiving apparatus 3001 is defined by the standard to operate at power consumption of 13 W or less until negotiation is established, the load unit 408 can not be activated. After that, when the negotiation is established, the control unit 407 activates the load unit 408 in S405. This negotiation may take several minutes.

  On the other hand, when the power supply apparatus 3000 has no power supply capability of 13 W or more and the negotiation is not established, the load unit 408 can not be activated. In that case, the process proceeds to S406. In S406, the control unit 407 cuts off the power supply by PoE and executes a process of stopping the power supply.

  Although the case of the power receiving device of TYPE 2 has been described in the above description, TYPE 1 may be used. In that case, since the power negotiation with the power supply apparatus 3000 does not have to be performed, the process of S404 can be omitted, and the process can proceed directly to S405. However, in the case of TYPE 1, the power consumption of the power receiving apparatus 3001 is limited to the load part that is 13 W or less.

  In step S402, the control unit 407 activates the load unit 408. In this case, the load unit 408 can be activated instantaneously. This is because the power negotiation in S404 can be omitted. That is, at the first start-up by the connection of the LAN cable 3002, negotiation with the power supply apparatus 3000 has been carried out, and the power consumption by the power consumption unit 412 continues without interruption of the PoE power supply. Is because it can be confirmed. In S403, the control unit 407 sets the output of the STOP terminal to Hi in order to stop the power consumption by the power consumption unit 412.

  As described above, according to the third embodiment, by using the power consumption by the power consumption unit 412, the control unit 407 and the load can continue without interruption of the power supply by PoE even while the operation of the voltage conversion unit 406 is stopped. The part 408 can be restarted. For this reason, since processing such as detection and classification for receiving PoE power can be omitted, it is possible to shorten the startup time. In addition, in the type 2 power receiving device, since it is not necessary to perform power negotiation, it is possible to further reduce the start-up time.

  In the above description, the operation state of the power consumption unit is implemented by detecting the voltage of the power consumption unit, but another method may be used. For example, a non-volatile memory may be provided, and the operation history of the power consumption unit may be stored in and read from the non-volatile memory to confirm.

  A more stable power supply can be provided by applying the PoE power control shown in the third embodiment to the PoE power supply section in the first and second embodiments.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. Can also be realized. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

  1000 imaging device; 1100 PSE; 1200 general-purpose power supply device; 2000 client device; 101 power supply unit; 102 isolated DCDC; 103 non-insulated DCDC; 104 voltage detection unit; 201 load unit; 301 control unit; 302 system controller; Rank determination unit; 304 communication unit; 305 memory

Claims (11)

A power supply apparatus which receives power from a first power supply and a second power supply and provides power to a load unit, the power supply apparatus comprising:
Voltage conversion means for converting a first voltage from the first power supply and outputting a first converted voltage;
Control means for controlling the first conversion voltage by the voltage conversion means;
Providing means for providing an output from a junction connecting the output of the second voltage from the second power supply and the output of the first conversion voltage from the voltage conversion means to the load portion;
Have
A power supply device characterized in that the control means determines the first conversion voltage based on which of the first power supply and the second power supply is to be prioritized to receive power. The information processing apparatus further comprises reception means for receiving an instruction input as to which one of the first power supply and the second power supply is to be preferentially received.
The power supply apparatus according to claim 1, wherein the control unit determines a power supply to which power is preferentially received based on an instruction input received by the reception unit. The power supply device according to claim 1, wherein the first power supply is a power supply that supplies power via a LAN cable. The junction according to any one of claims 1 to 3, wherein the junction is a diode OR connection of the output of the voltage conversion means through a first diode and the output of the second power supply through a second diode. The power supply device according to any one of the above. 5. The control method according to any one of claims 1 to 4, wherein, when it is determined that the first power supply is prioritized, the control means changes the first conversion voltage to be higher than the second voltage. The power supply device according to claim 1. 6. The control method according to any one of claims 1 to 5, wherein, when it is determined that the second power supply is prioritized, the control means changes the first conversion voltage to be lower than the second voltage. The power supply device according to claim 1. It further comprises detection means for detecting the second voltage,
The power supply according to any one of claims 1 to 6, wherein the control means further determines the first converted voltage by the voltage conversion means based on the voltage detected by the detection means. apparatus. The control means is configured to control the first converted voltage by controlling the resistance value of the variable resistor,
The control means
Determining a reference resistance value at which the voltage detected by the detection means and the first conversion voltage are equal;
When giving priority to the first power supply, the resistance value of the variable resistor is set to a value smaller than the reference resistance value in order to make the first conversion voltage higher than the second voltage.
When giving priority to the second power supply, setting the resistance value of the variable resistor to a value larger than the reference resistance value so as to make the first conversion voltage lower than the second voltage The power supply device according to claim 7, characterized in that. The power supply device according to any one of claims 1 to 8, wherein the load unit is an imaging device. Confirmation means for confirming whether the power supply to the first power supply is possible;
Power consumption means connected to the first power supply;
Signal holding means for holding a signal for controlling power consumption by the power consumption means;
A second control unit that operates with the power supplied from the voltage conversion unit and outputs the signal held by the signal holding unit;
And have
The second control means is
When the restart of the power supply device is executed by stopping the operation of the voltage conversion means, the signal holding means controls the predetermined signal to control the power consumption means to consume the power received from the first power supply. Stop the operation of the voltage conversion means,
After the operation of the voltage conversion means is restored, when the predetermined signal is held in the signal holding means, the power supply to the load unit is started without confirming whether the power is supplied by the confirmation means The power supply device according to any one of claims 1 to 9, wherein: A control method of a power supply device which receives power from a first power supply and a second power supply and provides power to a load unit, comprising:
A voltage conversion step of converting a first voltage from the first power supply and outputting a first converted voltage;
A control step of controlling the first conversion voltage by the voltage conversion means;
Providing an output from a junction connecting the output of the second voltage from the second power supply and the output of the first conversion voltage from the voltage conversion means to the load unit;
Including
In the control step, the first conversion voltage is determined based on which one of the first power supply and the second power supply is to be prioritized to receive power.

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