Power supply and power supply system

Abstract

To reduce standby power in a power saving state of an AC / DC power supply to improve a power saving efficiency, with a configuration simpler than a conventional configuration.SOLUTION: An embodiment of the present invention is a power supply that can be switched between a power saving state and a normal state, the power supply having: a first power supply system that is an output system of a DC power supply; a first control IC that controls the first power supply system and operates constantly; a second control IC that does not operate in the power saving state and operates in the normal state; and a transformer that outputs the voltage of the first power supply system, and that has an auxiliary winding for generating power to be supplied to the first control IC and the second control IC. When the power supply makes a transition from the power saving state to the normal state, the load current of the first power supply system increases before starting the supply of power to the second control IC.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to power saving in switching power supplies. [Background technology]

[0002] In recent years, growing environmental awareness has led to active efforts to reduce the standby power consumption of electronic devices. Even when an electronic device is not in operation, a certain amount of power is consumed as a loss within the AC / DC power supply used in the electronic device, and one such loss is the power consumed by the auxiliary power supply that operates the AC / DC power supply.

[0003] Figure 1 shows the configuration of a typical conventional AC / DC power supply. Power input from an AC power supply passes through input filter 101, is rectified to DC by diode bridge rectifier 102, and is smoothed by a capacitor. The DC power is then converted into pulsed AC by the high-speed switching of switching elements such as MOSFETs included in control circuit 104, and this is sent to the primary side (input side) of transformer 105. The power transmitted to the secondary side (output side) is rectified by rectifying elements such as diodes, smoothed by a capacitor on the secondary side, and output as DC power.

[0004] The transformer 105 is composed of a primary winding on the primary side and a secondary winding on the secondary side, and the voltage output to the secondary side is determined based on the ratio of the number of windings and the on / off ratio of the switch element. At this time, the rectified voltage on the secondary side is monitored, and the feedback unit 110 feeds back this voltage to the control IC 103 that controls the switch element, thereby keeping the output voltage on the secondary side constant.

[0005] In addition to the primary and secondary windings, an auxiliary winding is arranged inside transformer 105, and when power is transmitted from the primary side to the secondary side of the transformer, the power is also transmitted to the auxiliary winding. The power transmitted to the auxiliary winding is rectified by a rectifying element in smoothing circuit 107 and smoothed by a capacitor to generate an auxiliary power supply voltage.

[0006] The power supply voltage of the control IC 103 has a predetermined upper limit, and the auxiliary power supply voltage is dropped by a voltage dropper 106 before being input to the control IC 103 so that it does not exceed the upper limit. Furthermore, the control IC 103 may also have a built-in voltage dropper that drops the input voltage of the control IC 103 to a voltage used within the control IC 103 in order to generate the necessary voltage. If the difference between the input voltage and output voltage of the voltage dropper 106 becomes large, the power consumed by the voltage dropper 106 also increases, which causes a deterioration in the power-saving efficiency of the AC / DC power supply. This increases the power consumed by the auxiliary power supply, which causes a problem of a deterioration in the power-saving efficiency of the AC / DC power supply.

[0007] To solve this problem, Patent Document 1 discloses a configuration in which a transformer equipped with two types of auxiliary windings is used to select the appropriate auxiliary power supply voltage as needed from two types of auxiliary power supply voltages, a high voltage and a low voltage. A means for detecting each auxiliary power supply voltage is provided, and the optimum voltage is selectively used as the power supply voltage required for the control IC. By using the higher auxiliary power supply voltage when the lower auxiliary power supply voltage is insufficient to meet the power supply voltage required for the control IC, and otherwise using the lower auxiliary power supply voltage, it is possible to limit the voltage input to the control IC without passing through a voltage dropper.

[0008] One configuration for achieving power saving is to combine multiple control ICs (let's say a first control IC that operates constantly regardless of whether it is in a power-saving state or a normal state, and a second control IC that operates only in the normal state) with a switching power supply. In the power-saving state, only the circuit of the first control IC that supplies standby power operates, and supplies limited standby power to the main control circuit. In such a configuration, it is necessary to improve power efficiency in the power-saving state by minimizing the circuit systems that operate in the power-saving state. Note that operation in the normal state is defined as normal operation, and operation in the power-saving state is defined as power-saving operation.

[0009] Generally, a control IC has a specified start voltage for starting the power supply control operation, and it cannot start operating unless a voltage higher than this voltage is input. In the configuration having the first control IC and the second control IC described above, if a control IC voltage is determined that satisfies the start voltage for operating the first control IC, when power is applied to the second control IC, the condition for the start voltage of the second control IC may not be satisfied due to a voltage drop.

[0010] Furthermore, there are cases in which the operation start voltage of the second control IC is higher than that of the first control IC. In such cases, if the number of auxiliary windings is adjusted to output a control IC voltage that exactly satisfies the operation start voltage of the first control IC, the operation start voltage of the second control IC will not be satisfied.

[0011] Therefore, some kind of measure is necessary. For example, if the number of auxiliary windings is preset to output a control IC voltage that satisfies the operation start voltage of both the first control IC1 and the second control IC2, the control IC voltage output will be higher than the minimum voltage required for operation. As a result, a voltage dropper that adjusts the voltage higher than necessary will waste power, which will reduce power saving efficiency.

[0012] If it were possible to change the control IC voltage generated by the auxiliary winding depending on the operating state of the power supply, it would be possible to reduce the power consumed by the voltage dropper relative to the control IC voltage. By using the method described in Patent Document 1, it is possible to select an auxiliary power supply voltage that satisfies the operating voltage conditions of the control IC by switching between two types of auxiliary windings as needed. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-50220 Summary of the Invention [Problem to be solved by the invention]

[0014] However, the method of Patent Document 1 requires two types of auxiliary windings, which complicates the design of the transformer. In addition, it requires a switching circuit and a detection circuit to determine the switching conditions, which complicates the additional circuitry and increases the number of components.

[0015] Another possible configuration is to directly control the control IC from the main control circuit connected to the AC / DC power supply, outputting the required auxiliary power voltage at the required timing. However, in this case, the configuration becomes more complex, as it requires adding an insulating device such as a photocoupler to ensure insulation between the main control circuit and the primary side of the AC / DC power supply, and providing an external input terminal on the control IC side.

[0016] In view of the above problems, the present disclosure aims to reduce standby power consumption in the power saving state of an AC / DC power supply and improve power saving efficiency with a configuration simpler than conventional configurations. [Means for solving the problem]

[0017] One embodiment of the present invention is a power supply that can be switched between a power saving state and a normal state, and includes: a first power supply system that is an output system of a DC power supply; a first control IC that controls the first power supply system and operates at all times; a second control IC that does not operate in the power saving state but operates in the normal state; and a transformer that outputs a voltage of the first power supply system, the transformer having an auxiliary winding for generating power to be supplied to the first control IC and the second control IC; and when transitioning from the power saving state to the normal state, the load current of the first power supply system increases before power supply to the second control IC begins. [Effects of the Invention]

[0018] According to the present disclosure, it is possible to reduce standby power consumption in the power saving state of an AC / DC power supply and improve power saving efficiency with a configuration simpler than conventional configurations. [Brief explanation of the drawings]

[0019] [Figure 1] Block diagram showing the configuration of a conventional AC / DC power supply [Figure 2] FIG. 1 is a block diagram showing the configuration of a power supply system according to a first embodiment. [Figure 3] Timing chart for when power efficiency deteriorates in power-saving mode [Figure 4] 1 is a timing chart showing an example in which power efficiency in a power-saving state is improved according to the first embodiment; [Figure 5] Block diagram of the circuit around the first transformer in an AC / DC power supply [Figure 6] A block diagram showing the configuration of a main body control circuit according to the first embodiment. [Figure 7] FIG. 1 is a block diagram showing the configuration of an AC / DC power supply according to a variation of the first embodiment. [Figure 8] FIG. 1 is a block diagram showing the configuration of an AC / DC power supply according to a variation of the first embodiment. [Figure 9] FIG. 10 is a block diagram showing the configuration of a power supply system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] [First embodiment] <Power supply system configuration> 2 is a block diagram showing the configuration of the power supply system according to this embodiment. The AC / DC power supply 200 converts AC power from an outlet into DC power and supplies it to the main body control circuit 220. While an AC / DC power supply does not necessarily have one DC power output system, and an AC / DC power supply may output two or more DC power supplies, the AC / DC power supply 200 of this example has a first power supply system V1 and a second power supply system V2 as its output systems.

[0021] The AC / DC power supply 200 can also be switched between a power-saving operating state (referred to as a power-saving state) and a non-power-saving (i.e., normal power) operating state (referred to as a normal state), and has a receiving function for receiving a state switching signal (PW_CNT) for switching the operating state.

[0022] The main body control circuit 220 operates on power supplied via the DC power supply output systems (first power supply system V1, second power supply system V2) and realizes various functions. The main body control circuit 220 also has a function of controlling a state switching signal (PW_CNT) for switching the AC / DC power supply 200 between a power saving state and a normal state.

[0023] First, the internal circuit configuration of the AC / DC power supply 200 shown in FIG. 2 will be described.

[0024] Generally speaking, power input from an AC power supply passes through an input filter 201, is rectified to DC by a diode bridge rectifier 202, and is smoothed by a capacitor.

[0025] The power converted to DC is converted to pulsed AC by high-speed switching of semiconductor elements such as MOSFETs included in the first control circuit 204, and this AC is sent to the primary side (input side) of the first transformer 205. Thereafter, the power transmitted to the secondary side (output side) of the first transformer 205 is rectified by semiconductor elements such as diodes included in the first current smoothing circuit 214, smoothed by a capacitor on the secondary side, and output as DC power from the first power supply system V1.

[0026] Similarly, the power converted to DC is converted to pulsed AC by high-speed switching of semiconductor elements such as MOSFETs included in the second control circuit 210, and this AC is sent to the primary side (input side) of the second transformer 211. Thereafter, the power transmitted to the secondary side (output side) of the second transformer 211 is rectified by semiconductor elements such as diodes included in the second current smoothing circuit 218, smoothed by a capacitor on the secondary side, and output as DC power from the second power supply system V2.

[0027] <Start-up sequence of the first control IC> When an AC voltage is input to the AC / DC power supply 200 , the AC voltage is applied to the start-up terminal of the first control IC 203 , and the first control IC 203 starts the operation of the first control circuit 204 .

[0028] The first transformer 205 is composed of a primary winding on the primary side, a secondary winding on the secondary side, and an auxiliary winding for supplying power to the first control IC 203, the second control IC 209, and the third control IC 212.

[0029] A first control circuit 204 including a MOSFET sends pulse wave power to a first transformer 205 by high speed switching.

[0030] The first transformer 205 transmits power to the secondary winding on the secondary side and also to the auxiliary winding.

[0031] The power transmitted to the auxiliary winding is rectified and smoothed before being supplied as power for the control IC. First, the first control IC 203 is started by power from the AC voltage applied to the start terminal. When the first control IC 203 sends power to the first transformer 205, the voltage of the first power supply system V1 is output, and the voltage Vccic supplied from the auxiliary winding is also output. At this time, the power transmitted to the auxiliary winding is rectified by a rectifying element in the smoothing circuit 207 and smoothed by a capacitor to generate the voltage Vccic for the control IC. The switch 208 is a switching means for switching between supplying and stopping power to the second control IC 209 and the third control IC 212.

[0032] When the control IC voltage Vccic supplied from the auxiliary winding exceeds the operation start voltage (Vstart1) of the first control IC 203, the first control IC 203 starts to operate using power from the auxiliary winding instead of power from the AC voltage.

[0033] <Switching sequence between power saving state and normal state> The state switching signal (PW_CNT) for switching the operating state of the ACDC power supply 200 is a signal that, at a High level, puts the ACDC power supply 200 into a normal state, and at a Low level, puts the ACDC power supply 200 into a power saving state. Immediately after an AC voltage is input to the ACDC power supply 200, the state switching signal (PW_CNT) is at a Low level, and the ACDC power supply 200 is in a power saving state. For simplicity, hereinafter, "High level" will be abbreviated as "High" and "Low level" as "Low."

[0034] When the main body control circuit 220 transitions the AC / DC power supply 200 from the power saving state to the non-power saving normal state, it changes the state switching signal (PW_CNT) from Low to High. Then, the power of the control IC voltage Vccic supplied via the auxiliary winding is supplied to the second control IC 209 and the third control IC 212, and the second control IC 209 and the third control IC 212 start operating.

[0035] Regarding the second control IC 209 and the third control IC 212, these ICs are not limited to being used for a specific function, but in this embodiment, the second control IC 209 is an IC for controlling the second control circuit 210 that generates the second power supply system V2. Also, the third control IC 212 is a power factor correction circuit (PFC) that improves the power factor of the AC / DC power supply 200. The second power supply system V2 and the power factor correction circuit are circuits that do not operate in a power saving state, but operate only in a normal state.

[0036] <Switching from power saving mode to normal mode> 3 is a timing chart showing the control IC voltage Vccic and the operation (oscillation) timing of the first control IC 203 when the AC / DC power supply 200 switches from the power saving state to the normal state. The oscillation period of the first control IC 203 varies depending on the current consumption of the first power supply system V1. In the power saving state, the current consumption of the first power supply system V1 is kept low, and when the load current of the first power supply system V1 is large, the oscillation period of the first control IC 203 becomes shorter, and when the load current is small, the oscillation period becomes longer. In other words, the oscillation period of the first control IC 203 changes between when Is = Is_tmp and when Is = Is_min in FIG. 4, which will be described later.

[0037] If the operation start voltage (Vstart2) of the second control IC 209 is higher than the control IC voltage Vccic, the second control IC 209 cannot be started even if power is supplied to the second control IC 209. Similarly, if the operation start voltage (Vstart3) of the third control IC 212 is higher than the control IC voltage Vccic, the third control IC 212 cannot be started even if power is supplied to the third control IC 212.

[0038] To start the second control IC 209, the number of auxiliary windings on the first transformer must be adjusted so that the control IC voltage Vccic is higher than the operation start voltage Vstart2 of the second control IC 209. Similarly, to start the third control IC 212, the number of auxiliary windings on the first transformer must be adjusted so that the control IC voltage Vccic is higher than the operation start voltage Vstart3 of the third control IC 212. For example, if Vstart2 = 10V and Vstart3 = 12V, Vccic must be 12V or higher. If Vccic = 11V, the second control IC will be able to operate, but the third control IC will not.

[0039] <Deterioration in power efficiency> In other words, when the AC / DC power supply 200 is in the power-saving state, it is sufficient that the control IC voltage Vccic remains higher than the operation start voltage Vstart1. However, to switch the AC / DC power supply 200 to the normal state, the control IC voltage Vccic must be set to a voltage higher than each of the operation start voltages Vstart2 and Vstart3. Therefore, the number of auxiliary windings of the first transformer 205 must be set to be greater than the number of windings required in the power-saving state.

[0040] For example, assume that the number of auxiliary windings in the first transformer 205 is 10 so that the control IC voltage Vccic is higher than the operation start voltage Vstart1, and the number of auxiliary windings in the first transformer 205 is 14 so that the control IC voltage Vccic is higher than the operation start voltage Vstart2. Under this assumption, the number of auxiliary windings in the first transformer 205 needs to be set to at least 14 or more.

[0041] However, setting a larger number of auxiliary windings has the drawback of degrading power efficiency in the power-saving state. In other words, even when the AC / DC power supply 200 is in the power-saving state, the control IC voltage Vccic is maintained at a high voltage value. Therefore, the power corresponding to the voltage difference between the operation start voltage Vstart1 of the first control IC 203 and the control IC voltage Vccic is consumed by the dropper circuit in the first control IC 203. This degrades power efficiency in the power-saving state.

[0042] <Timing chart for improving power efficiency> 4 is a timing chart showing the control IC voltage Vccic and the operation timing of the first control IC 203 when the AC / DC power supply 200 switches from a power-saving state to a normal state in this embodiment. As shown in the figure, in the power-saving state after the AC / DC power supply 200 starts operating, the load current Is of the first power supply system V1 is small, so the oscillation period of the first control IC 203 is long. The number of auxiliary windings is set so that the control IC voltage Vccic at this time is higher than the operation start voltage Vstart1 of the first control IC 203. Let us assume that the number of auxiliary windings is 10.

[0043] In this embodiment, in the power saving state, the control IC voltage Vccic is set to a voltage higher than the operation start voltage Vstart1 of the first control IC 203. This voltage is the minimum required voltage, which contributes to improving the power efficiency of the AC / DC power supply 200 in the power saving state.

[0044] However, since the control IC voltage Vccic in the power saving state is lower than the operation start voltage Vstart2 and the operation start voltage Vstart3, the second control IC 209 and the third control IC 212 cannot be started even if the state switching signal is changed to High.

[0045] Therefore, in this embodiment, before changing the state switching signal to High, a load control signal for controlling each of the multiple loads is used to select an appropriate load. The selected load is then connected to the first power supply system V1, thereby increasing the load current Is. Here, the load current in the power-saving state is defined as Is_min, and the load current when temporarily increased is defined as Is_tmp. Increasing the load current Is shortens the oscillation period of the first control IC 203, thereby enabling the control IC voltage Vccic to be increased. A load that generates a load current Is_tmp such that Vccic > Vstart2 and Vccic > Vstart3 is selected. After the load current Is is increased, a certain time is required for the control IC voltage Vccic to exceed the operation start voltage Vstart2 and the operation start voltage Vstart3, respectively. This time is referred to as a preparation time T_pre. Note that in a typical power supply control IC, this time is approximately several tens to several hundreds of milliseconds.

[0046] After the load current Is_tmp is applied and the control IC voltage Vccic exceeds the operation start voltage Vstart2 and the operation start voltage Vstart3, the state switching signal is changed from Low to High. This enables the second control IC 209 and the third control IC 212 to be started. The load current Is_tmp is only required when the AC / DC power supply 200 transitions from the power saving state to the normal state, so it does not increase power consumption in the power saving state.

[0047] Regarding the control timing of the load control signal and the state switching signal, a preparation time T_pre required for calculation, experiment, etc. is defined in advance and stored as a control program for the controller 221 in the main body control circuit 220 .

[0048] <Selection of preparation time T_pre> The larger the load current Is_tmp, the shorter the preparation time T_pre. Therefore, it is recommended to prepare in advance the preparation time T_pre required for each load current Is_tmp corresponding to the selected load and store it in a storage medium within the controller. The optimal preparation time T_pre corresponding to the selected load can be selected and used to control the load control signal and the state switching signal.

[0049] <How to determine the number of auxiliary windings Nd and the load current Is_tmp> FIG. 5 is a block diagram of an extracted circuit around the first transformer 205 of the AC / DC power supply shown in FIG.

[0050] The first transformer 205 is composed of a primary winding on the primary side, a secondary winding on the secondary side, and an auxiliary winding for supplying power to the first control IC 203, the second control IC 209, and the third control IC 212. When the first control IC 203 sends power to the primary winding of the first transformer 205, the voltage of the first power supply system V1 is output, and the voltage Vccic supplied from the auxiliary winding is also output. The voltage of the first power supply system V1 is transmitted from the feedback unit 216 to the first control IC 203 via the photocoupler 215, and feedback control is performed, so the voltage of the first power supply system V1 is kept constant regardless of the magnitude of the load current. On the other hand, the voltage Vccic supplied from the auxiliary winding is not subject to feedback control, so the voltage fluctuates depending on the magnitude of the load current of the first power supply system V1.

[0051] The following relationship holds for the control IC voltage Vccic, the auxiliary winding voltage Vd, and the load current Is of the first power supply system V1. (Voltage Vccic for control IC)=(Oscillation frequency of first control circuit 204)×(Voltage Vd of auxiliary winding) Equation (1) (Oscillation frequency of the first control circuit 204)=(Coefficient)×(Load current Is of the first power supply system V1) Equation (2) (Auxiliary winding voltage Vd) = (Number of auxiliary winding turns Nd) / (Number of primary winding turns Np) × (Primary winding voltage Vp) Equation (3) The control IC voltage Vccic is proportional to the oscillation frequency of the first control circuit 204 and the auxiliary winding voltage Vd. Furthermore, the oscillation frequency of the first control circuit 204 is proportional to the load current Is of the first power supply system V1, and the auxiliary winding voltage Vd is proportional to the number of turns Nd of the auxiliary winding. Therefore, the control IC voltage Vccic is proportional to the load current Is of the first power supply system V1 and the number of turns Nd of the auxiliary winding.

[0052] The number of turns Nd of the auxiliary winding is physically determined to be one value, but the load current Is of the first power supply system V1 varies depending on the load current of the load on the control circuit side connected to the first power supply system V1.

[0053] In this embodiment, the load current Is_min of the first power supply system V1 and the number of turns Nd of the auxiliary winding are determined so that the control IC voltage Vccic in the power saving state exceeds the operation start voltage Vstart1 of the first control IC 203. Then, the load current Is_tmp of the first power supply system V1 is determined so that the control IC voltage Vccic exceeds both the operation start voltage Vstart2 of the second control IC 209 and the operation start voltage Vstart3 of the third control IC 212.

[0054] In this embodiment, before changing the state switching signal to High, the load current of the first power supply system V1 is increased from Is_min to Is_tmp using a load control signal. The loads selectively used at this time are one or more of the loads present on the main body control circuit 220, and the load current Is of the first power supply system V1 is increased by connecting the one or more loads. After increasing the load current, the state switching signal is changed to High after a preparation time T_pre has elapsed until the voltage level of the control IC voltage Vccic increases.

[0055] <Details of the main control circuit> The main body control circuit 220 of the power supply system shown in Fig. 2 will be described below with reference to Fig. 6. A controller such as a microcomputer is mounted on the main body control circuit 220, and the controller can operate using power from the first power supply system V1. A load on the main body control circuit 220 is connected to the first power supply system V1 via a switch device such as an FET or a load switch, and the controller can connect the first power supply system V1 to the load by controlling the switch device.

[0056] 6 is a block diagram showing a specific example of the internal configuration of the main body control circuit 220. Note that, although the main body control circuit will be described here as a controller board that operates the inkjet printer, this is merely an example.

[0057] Examples of loads connected to the first power supply system V1 on the main body control circuit 220 include an operation panel circuit 622, a storage circuit 623, an ASIC 624, and a sensor control circuit 627. In addition, loads connected to the second power supply system V2 include a motor control circuit 625 and a print head control circuit 626. A controller 621 connected to the first power supply system V1 on the main body control circuit 220 can control whether or not to supply power to the loads connected to the first power supply system V1 and the loads connected to the second power supply system V2.

[0058] <Load Selection> The load selection control by the controller 621 mounted on the main body control circuit 220 will now be described. The controller 621 controls the first power supply system V1 to generate a load current equivalent to Is_tmp by connecting, for example, the operation panel circuit 622 as a load, raise the voltage level of Vccic, and then change the state switching signal from Low to High. The load current generated by connecting the operation panel circuit 622 must exceed Is_tmp and be smaller than the maximum current Is_max that the first control circuit 204 can supply when the AC / DC power supply 200 is in a power-saving state. The load current may be generated using a single specific load or multiple loads. In other words, in the example shown in FIG. 6 , the load connected to the first power supply system V1 may be a single load or a combination of multiple loads. To cover the load current equivalent to Is_tmp, the load of the operation panel circuit or the load of the operation panel circuit and the storage circuit may be used. Loads such as the operation panel circuit, storage circuit, and ASIC are originally required under normal conditions, but a resistive load that matches the required amount of Is_tmp can be prepared separately and used as a circuit for generating the load current of Is_tmp in this embodiment.

[0059] <Load selection control method> There are multiple factors that cause the transition from the power-saving state to the normal state (this state transition is called "return"). During such a return, the control method may be changed so that a load that needs to be operated quickly in accordance with the functions of the main body control circuit 220 is used preferentially as a load equivalent to Is_tmp. For example, when a transition from the power-saving state to the normal state is triggered by a user's key operation, the operation panel circuit 622 is used as a load equivalent to Is_tmp in order to display the operation panel as quickly as possible. Also, when a transition from the power-saving state to the normal state is triggered by receiving print data from an information processing device (PC), the storage circuit 623 that receives the print data is used as a load equivalent to Is_tmp. This allows the operation of receiving the print data to start sooner.

[0060] <Examples of specific roles of each IC> In this embodiment, the roles of the first control IC, the second control IC, and the third control IC may be, for example, as follows.

[0061] The first control IC is a control IC that generates voltages for the first power supply system and the auxiliary winding, and may be a power supply control IC that uses any control method such as a flyback type, a forward type, or an LLC type.

[0062] The second control IC is a control IC for the second power supply system, and may be a power supply control IC using any control method such as the flyback type, forward type, LLC type, etc. In order to improve the power efficiency of the AC / DC power supply during power-saving operation, it is configured to not operate during power-saving operation, thereby reducing unnecessary power consumption.

[0063] The third control IC is a control IC for controlling the power factor correction circuit placed after the diode bridge. This circuit is required when the first and second power supply systems output relatively large amounts of power during normal operation, and does not operate when the AC / DC power supply itself is in power-saving mode.

[0064] 7 and 8 are block diagrams showing the configuration of an ACDC power supply 200 according to the first embodiment, which is a different form from that described above (see FIG. 2). As described above, the first control IC operates constantly, and the second control IC and the third control IC operate only in the normal state, but the roles and types of the control ICs are not particularly limited, and FIGS. 7 and 8 each show variations of the first embodiment.

[0065] That is, the AC / DC power supply 200 may be an AC / DC power supply configured with two control ICs, a first control IC 703 of a flyback type and a second control IC 709 of an LLC type, as shown in Fig. 7. Alternatively, it may be an AC / DC power supply configured with two control ICs, a first control IC 803 of a flyback type and a third control IC 809 that is a power factor correction circuit (PFC), as shown in Fig. 8.

[0066] [Second embodiment] 9 is a block diagram showing the configuration of an AC / DC power supply 200 according to this embodiment. The AC / DC power supply 200 according to this embodiment differs from the first embodiment in that it includes a load control circuit 919 and a load 920 (see FIG. 2).

[0067] When the state switching signal input to the ACDC power supply 200 changes from low to high, the state switching signal is input to a load control circuit in the ACDC power supply 200, and the load control circuit supplies power to a load connected to the first power supply system V1 in the ACDC power supply 200. This load is, for example, a resistor or other load for generating a load current equivalent to Is_tmp. After a certain time has passed since Is_tmp occurred, the load control circuit supplies power from the control IC voltage Vccic to the second control circuit 911 and the third control circuit 913.

[0068] According to this embodiment, the controller on the main body control circuit 220 connected to the AC / DC power supply 200 can change the control of the state switching signal from Low to High and transition from the power saving state to the normal state without being aware of generating Is_tmp.

[0069] The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0070] [Technical Features of the Disclosure] The present disclosure includes the following configurations.

[0071] (Configuration 1) A power supply that can be switched between a power saving state and a normal state, comprising: a first power supply system that is an output system of a DC power supply; a first control IC that controls the first power supply system and operates at all times; a second control IC that does not operate in the power saving state and operates in the normal state; and a transformer that outputs the voltage of the first power supply system, the transformer having an auxiliary winding for generating power to be supplied to the first control IC and the second control IC, wherein when transitioning from the power saving state to the normal state, the load current of the first power supply system increases before starting to supply power to the second control IC. (Configuration 2) The power supply according to configuration 1, further comprising: a smoothing circuit that smoothes the power transmitted to the auxiliary winding to generate a voltage for a control IC; and a switching means that switches whether or not to supply power to the second control IC. (Configuration 3) The power supply according to configuration 1 or 2, characterized in that the number of turns of the auxiliary winding is set so that the voltage for the control IC in a power saving state is greater than the operation start voltage of the first control IC. (Configuration 4) A power supply according to any one of configurations 1 to 3, characterized in that the number of turns of the auxiliary winding is set so that the voltage for the control IC in a normal state is greater than the operation start voltage of the second control IC. (Configuration 5) The power supply according to any one of configurations 1 to 4, further comprising a load and a load control circuit, wherein the load control circuit increases the load current by connecting the load to the first power supply system. (Configuration 6) The power supply according to any one of configurations 1 to 5, further comprising a receiving means for receiving a switching signal for switching between a power saving state and a normal state. (Configuration 7) A power supply system comprising the power supply according to any one of configurations 1 to 6 and a control circuit connected to the power supply. (Configuration 8) The power supply system according to configuration 7, characterized in that the control circuit has a controller that controls the connection of a load to the first power supply system, a plurality of loads, and a transmitting means that transmits the switching signal to the power supply. (Configuration 9) The power supply system according to configuration 8, wherein the controller increases the load current by connecting the load to the first power supply system. (Configuration 10) A power supply system described in any of configurations 7 to 9, characterized in that the time from the first timing when the load current of the first power supply system increases to the second timing when the power saving state transitions to the normal state is shorter as the load current of the first power supply system is larger. (Configuration 11) A power supply system described in any of configurations 7 to 10, characterized in that there are multiple factors that cause a transition from a power saving state to a normal state, and a load to be connected to the first power supply system is selected from the multiple loads depending on the type of factor. (Configuration 12) A power supply system described in any of configurations 7 to 11, characterized in that the controller connects a load selected from the plurality of loads to the first power supply system, and after the preparation time has elapsed, changes the switching signal sent to the power supply from a low level to a high level. [Explanation of symbols]

[0072] 200 ACDC power supply 203 First control IC 205 1st Trans 209 Second control IC V1 1st power supply system

Claims

1. A power supply that can be switched between a power saving state and a normal state, a first power supply system which is a DC power supply output system; a first control IC that controls the first power supply system and operates at all times; a second control IC that does not operate in a power saving state and operates in a normal state; a transformer that outputs a voltage of the first power supply system, the transformer having an auxiliary winding for generating power to be supplied to the first control IC and the second control IC; having When transitioning from a power saving state to a normal state, the load current of the first power supply system increases before starting to supply power to the second control IC.

1. A power supply comprising:

2. The power supply circuit further includes a smoothing circuit that smoothes the power transmitted to the auxiliary winding to generate a voltage for a control IC, and a switching means that switches whether or not to supply power to the second control IC.

2. The power supply of claim 1.

3. The number of turns of the auxiliary winding is set so that the voltage for the control IC in a power saving state is greater than the operation start voltage of the first control IC.

3. The power supply of claim 2.

4. The number of turns of the auxiliary winding is set so that the voltage for the control IC in a normal state is greater than the operation start voltage of the second control IC.

4. The power supply of claim 3.

5. a load and a load control circuit; the load control circuit increases a load current by connecting the load to the first power supply system; 5. A power supply according to any one of the preceding claims.

6. The power supply unit further includes a receiving means for receiving a switching signal for switching between the power saving state and the normal state.

5. A power supply according to any one of the preceding claims.

7. A power supply system comprising: a power supply according to claim 6; and a control circuit connected to the power supply.

8. The control circuit includes: A controller for controlling a connection of a load to the first power supply system; Multiple loads and A transmitting means for transmitting the switching signal to the power source; having 8. The power supply system according to claim 7.

9. The controller increases a load current by connecting the load to the first power supply system.

9. The power supply system according to claim 8.

10. a time period from a first timing at which the load current of the first power supply system increases to a second timing at which the power saving state transitions to a normal state is shorter as the load current of the first power supply system is larger; 9. The power supply system according to claim 8.

11. There are several factors that cause the device to transition from power saving to normal mode. a load to be connected to the first power supply system is selected from the plurality of loads according to the type of the factor; 11. The power supply system according to claim 10.

12. the controller connects a load selected from the plurality of loads to the first power supply system, and after the time has elapsed, changes the switching signal transmitted to the power supply from a low level to a high level; 12. The power supply system according to claim 11.

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