JP6294770B2 - Switching power supply - Google Patents

Description

  The present invention relates to a switching power supply.

  As a conventional switching power supply, for example, Patent Document 1 discloses a control circuit for a switching converter that rectifies a first switch and a second switch alternately turned on. The control circuit of the switching converter includes a plurality of first drive units that respectively drive the plurality of first switches, a second drive unit that drives the second switches, a load current, an input voltage, an output voltage, or A selection unit that stops a part of the plurality of first drive units according to the input / output voltage difference.

JP 2006-296186 A

  By the way, the control circuit of the above-described switching converter is desired to further improve the power conversion efficiency, for example.

  This invention is made | formed in view of said situation, Comprising: It aims at providing the switching power supply which can improve power conversion efficiency.

In order to achieve the above object, a switching power supply according to the present invention has a plurality of switching systems that can be individually switched between a driving state that converts an input voltage and generates an output voltage, and a stopped state that stops power conversion. A power supply circuit having a power conversion unit, and calculates the power conversion efficiency of the power supply circuit, and based on the calculated power conversion efficiency and the load factor of the power conversion unit in the driving state, the plurality of power conversion units And a control device capable of executing control for switching between the drive state and the stop state individually, and the control device is in a state where the number of the power conversion units in the drive state is relatively small. A drive determination efficiency rule in which the load factor of the power conversion unit in the drive state is equal to or greater than a preset drive determination load factor prescribed value, and the power conversion efficiency of the power supply circuit is preset. The number of the power conversion units in the driving state is relatively large when the power conversion unit is less than the value, and the number of the power conversion units in the driving state is relatively small. Even if the load factor is equal to or greater than the drive determination load factor specified value, the number of the power conversion units in the drive state is relatively large when the power conversion efficiency of the power supply circuit is equal to or greater than the drive determination efficiency specified value. When the load ratio of the power conversion unit in the driving state is relatively less than the prescribed value for the load determination for driving determination, the number of the power conversion units in the driving state is relatively small The load of the power conversion unit in the driving state while the number of the power conversion units in the driving state is maintained in a relatively small state and the number of the power conversion units in the driving state is relatively large Negative for stop judgment with rate set in advance If the power conversion efficiency of the power supply circuit in the driving state is less than a predetermined value, and the power conversion efficiency in the driving state is less than a preset efficiency determining value for stop determination, the number of the power conversion units in the driving state is relatively Even if the load factor of the power conversion unit in the driving state is less than the prescribed value for the stop determination load factor in a state where the number of the power conversion units in the driving state is relatively large When the power conversion efficiency of the circuit is equal to or greater than the efficiency determination value for stop determination, the number of the power conversion units in the driving state is maintained relatively large, and the number of the power conversion units in the driving state When the load factor of the power conversion unit in the drive state is greater than or equal to the stop determination load factor prescribed value in a relatively large state, the number of the power conversion units in the drive state is relatively large. It is characterized by maintaining as it is.

  In the switching power supply, the control device further controls the plurality of power conversion units based on a load factor of the power conversion unit in the drive state, and individually controls the drive state and the stop state. It is possible to execute control for switching between.

  Further, in the switching power supply, the control device is a drive determination load in which a load factor of the power conversion unit in the drive state is set in advance with a relatively small number of the power conversion units in the drive state. When the power conversion efficiency of the power supply circuit is equal to or greater than a specified rate value and less than a preset drive determination efficiency specified value, the number of the power conversion units in the drive state is relatively increased, The load factor of the power conversion unit in the drive state in a state where the number of the power conversion units in the drive state is relatively large is less than a preset load determination threshold value for stop determination, and the drive state is When the power conversion efficiency of a certain power supply circuit is less than the preset stop regulation efficiency prescribed value, the number of the power conversion units in the drive state can be relatively reduced.

  In the switching power supply, hysteresis may be set for the drive determination load factor specified value and the stop determination load factor specified value.

  In the switching power supply, the control device obtains load information of an electric device to which power converted by the power supply circuit is supplied, controls the plurality of power conversion units based on the load information, and individually In addition, it is possible to execute control for switching between the driving state and the stopped state.

  Since the switching power supply according to the present invention calculates the power conversion efficiency of the power supply circuit by the control device, and executes control for individually switching the drive state / stop state of each power conversion unit based on the calculated power conversion efficiency. The state of each power conversion unit can be switched so that the actual power conversion efficiency is optimized. As a result, the switching power supply can improve the power conversion efficiency.

FIG. 1 is a configuration diagram illustrating a schematic configuration of a switching power supply according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the switching power supply control device according to the first embodiment. FIG. 3 is a diagram for explaining an example of characteristics relating to temperature and power conversion efficiency in the switching power supply according to the first embodiment. FIG. 4 is a diagram illustrating an example of characteristics relating to load factor and power conversion efficiency in the switching power supply according to the first embodiment. FIG. 5 is a flowchart illustrating an example of switching control by the switching power supply controller according to the first embodiment. FIG. 6 is a block diagram illustrating an example of a schematic configuration of a control device for a switching power supply according to the second embodiment. FIG. 7 is a flowchart illustrating an example of switching control by the switching power supply control device according to the second embodiment. FIG. 8 is a flowchart illustrating another example of the switching control by the switching power supply control device according to the second embodiment. FIG. 9 is a flowchart illustrating an example of notification control by the switching power supply control device according to the second embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
FIG. 1 is a configuration diagram illustrating a schematic configuration of a switching power supply according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the switching power supply control device according to the first embodiment. FIG. 3 is a diagram for explaining an example of characteristics relating to temperature and power conversion efficiency in the switching power supply according to the first embodiment. FIG. 4 is a diagram illustrating an example of characteristics relating to load factor and power conversion efficiency in the switching power supply according to the first embodiment. FIG. 5 is a flowchart illustrating an example of switching control by the switching power supply controller according to the first embodiment.

  A switching power supply 1 according to this embodiment shown in FIG. 1 includes a switching power supply circuit 2 that converts an input voltage Vin to generate an output voltage Vout, and a control device that controls a switching element (transistor 23) of the power supply circuit 2. 3. The switching power supply 1 generates and outputs a stable DC voltage from the power supply circuit 2 by controlling the ON / OFF of the switching element of the power supply circuit 2 by the control device 3.

  The power supply circuit 2 according to this embodiment is a switching step-down DC-DC converter circuit including an input terminal 21, an output terminal 22, a plurality of transistors 23 as switching elements, an inductor 24, a capacitor 25, and the like. . The input terminal 21 is connected to a DC power source such as a battery, and an input voltage Vin is input as DC power from the DC power source. The output terminal 22 is connected to an electric device that consumes power, and outputs the output voltage Vout converted by the power supply circuit 2 to the electric device. In the power supply circuit 2, a plurality of transistors 23 are connected in parallel between an input terminal 21 and an output terminal 22, and an inductor 24 and a capacitor 25 are disposed on the output terminal 22 side. The power supply circuit 2 is configured to allow a relatively large current to flow through the entire circuit by providing a plurality of transistors 23 serving as switching elements in parallel.

  More specifically, the power supply circuit 2 of the present embodiment includes a plurality of transistors 23 including a total of eight transistors 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h. For example, a field effect transistor (FET) can be used as the transistors 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h. However, the present invention is not limited to this, and other switching elements may be used. . Here, in the transistors 23a, 23b, 23e, and 23f, the input terminal 21 is connected to the drain terminal, one end of the inductor 24 and the drain terminals of the transistors 23c, 23d, 23g, and 23h are connected to the source terminal, and the gate terminals are controlled. Device 3 is connected. In the transistors 23c, 23d, 23g, and 23h, one end of the inductor 24 and the source terminals of the transistors 23a, 23b, 23e, and 23f are connected to the drain terminal, the GND terminal is connected to the source terminal, and the control device 3 is connected to the gate terminal. Is done. As described above, the inductor 24 has one end connected to the source terminals of the transistors 23a, 23b, 23e, and 23f and the drain terminals of the transistors 23c, 23d, 23g, and 23h, and the other end connected to one end of the capacitor 25 and the output terminal 22. Is done. The capacitor 25 is a smoothing capacitor, and as described above, the other end of the inductor 24 and the output terminal 22 are connected to one end, and the GND terminal is connected to the other end. In the following description, the plurality of transistors 23 a, 23 b, 23 c, 23 d, 23 e, 23 f, 23 g, and 23 h may be simply referred to as “transistor 23” when it is not necessary to particularly distinguish them.

  The power supply circuit 2 of the present embodiment can be individually switched between a driving state (power conversion state) in which the input voltage Vin is converted and the output voltage Vout is generated by a plurality of transistors 23 and a stop state in which power conversion is stopped. A plurality of power conversion units 26 of a certain switching system are configured. Here, the transistors 23a, 23b, 23c, and 23d belonging to the area A constitute the first power conversion unit 26a, and the transistors 23e, 23f, 23g, and 23h belonging to the area B constitute the second power conversion unit 26b. . The power supply circuit 2 individually controls on / off of the plurality of transistors 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h, so that the first power conversion unit 26a and the second power conversion unit 26b The driving state and the stopped state can be switched individually. The power supply circuit 2 is configured such that the duty period (ON period) of the transistor 23 is controlled by the control device 3 in each power conversion unit 26 (first power conversion unit 26a, second power conversion unit 26b). Is converted into a DC output voltage Vout and output from the output terminal 22 to an electrical device.

  As shown in FIG. 2, the control device 3 includes a control IC (Integrated Circuit) 31, a switching device 32, and a driver IC 33. The driver IC 33 is provided in two systems corresponding to the plurality of power conversion units 26, here, the first power conversion unit 26a and the second power conversion unit 26b. In other words, the driver IC 33 includes a first driver IC 33a provided corresponding to the first power converter 26a and a second driver IC 33b provided corresponding to the second power converter 26b.

  The control IC 31 controls driving of the power supply circuit 2 and is an integrated circuit including an electronic circuit mainly composed of a known microcomputer including a CPU, a ROM, a RAM, and an interface. The control IC 31 is connected to the gate terminal of each transistor 23 via the switching device 32, the driver IC 33, and the like, and to the output terminal 22 of the power supply circuit 2 via the voltage detection line 4 (see FIG. 1 and the like). The output voltage Vout from the power supply circuit 2 is input. The control IC 31 controls, for example, the transistor 23 that is a switching element of the power supply circuit 2 based on the difference voltage between the target voltage and the output voltage Vout from the power supply circuit 2, and outputs the output voltage Vout from the power supply circuit 2. The feedback control is performed so as to converge to the target voltage. The control IC 31 calculates the control amount of each transistor 23 based on the voltage difference between the target voltage and the output voltage Vout, and controls each transistor 23 based on the control amount.

  The switching device 32 switches the connection relationship between the control IC 31 and each driver IC 33 (first driver IC 33a, second driver IC 33b). The switching device 32 includes switches SW1, SW2, SW3, and SW4. The switches SW1 and SW2 can be switched between a connection state (ON) in which the control IC 31 and the first driver IC 33a are connected, and a cutoff state (OFF) in which the connection between the control IC 31 and the first driver IC 33a is cut off. The switches SW3 and SW4 can be switched between a connection state (ON) in which the control IC 31 and the second driver IC 33b are connected, and a cutoff state (OFF) in which the connection between the control IC 31 and the second driver IC 33b is cut off.

  The control IC 31 can switch the states of the switches SW1, SW2, SW3, and SW4 by outputting a signal 5 (signals 1 to 4 will be described later) to the switching device 32. Here, the signal 5 is a SW control signal for controlling the state of each switch SW1, SW2, SW3, SW4 of the switching device 32. Each switch SW1, SW2, SW3, SW4 of the switching device 32 is switched on / off based on a signal 5 input from the control IC 31. The control IC 31 can turn on the switches SW1 and SW2 to place the first power conversion unit 26a in the drive state (power conversion state), and turn off the switches SW1 and SW2 to turn off the first power conversion unit 26a. Can be put into a stopped state. Similarly, the control IC 31 can turn on the switches SW3 and SW4 to place the second power converter 26b in a driving state (power conversion state), and turn off the switches SW3 and SW4 to turn on the second power. Conversion part 26b can be made into a halt condition.

  The driver IC 33 (the first driver IC 33a and the second driver IC 33b) outputs signals 1 to 4 to each transistor 23 in response to a command from the control IC 31, and actually controls the drive. , An integrated circuit including an electronic circuit mainly including a well-known microcomputer including a RAM and an interface. Here, the first driver IC 33a is connected to the transistors 23a, 23b, 23c, and 23d constituting the first power conversion unit 26a, and outputs a common signal 1 to the transistors 23a and 23b, whereby the transistor 23a, The on / off of the transistors 23c and 23d is controlled by controlling the on / off of the transistors 23b and outputting the common signal 2 to the transistors 23c and 23d. The second driver IC 33b is connected to the transistors 23e, 23f, 23g, and 23h constituting the second power conversion unit 26b, and outputs a common signal 3 to the transistors 23e and 23f, thereby turning on the transistors 23e and 23f. Controlling off and outputting the common signal 4 to the transistors 23g and 23h controls the on / off of the transistors 23g and 23h. Here, the signals 1 to 4 are PWM signals for controlling on / off of each transistor 23. Each transistor 23 is switched on / off based on signals 1 to 4 input from the control IC 31 via each driver IC 33.

  More specifically, the control IC 31 calculates a differential voltage between the target voltage and the output voltage Vout from the power supply circuit 2 input via the voltage detection line 4. The target voltage is a voltage that is a target of the output voltage Vout in the feedback control, and is typically determined according to a voltage or the like required by an electric device connected to the power supply circuit 2. Then, the control IC 31 calculates the control amount of each transistor 23 based on the difference voltage between the calculated target voltage and the output voltage Vout. Here, the control amount of each transistor 23 is typically a duty period corresponding to the length of the ON period of the transistor 23 that is a switching element. The output voltage Vout of the power supply circuit 2 becomes relatively larger as the duty period in each transistor 23 becomes relatively longer, and becomes relatively smaller as the duty period becomes relatively shorter. The control IC 31 is configured so that the difference voltage between the calculated target voltage and the output voltage Vout is reduced by so-called P control, PI control, or PID control (that is, the output voltage Vout converges to the target voltage). A duty period which is a control amount of the transistor 23 is calculated. In the control IC 31, for example, a control amount map (or a mathematical model) that defines a correspondence relationship between a difference voltage between the target voltage and the output voltage Vout and a duty period that is a control amount of the transistor 23 is stored in the storage unit. Then, the control target duty period is calculated from the difference voltage between the target voltage and the output voltage Vout using the control amount map. Specifically, the control IC 31 relatively increases the duty period as the difference voltage between the target voltage and the output voltage Vout is relatively large, and relatively shortens the duty period as the difference voltage is relatively small. To do. Then, the control IC 31 outputs a command to each driver IC 33 based on the calculated duty period, generates a PWM signal (pulse signal) that is pulse-width modulated by each driver IC 33, and outputs each of the transistors 23 as signals 1 to 4. And the transistor 23 is turned on / off so that the output voltage Vout converges to the target voltage.

  And control IC31 of the control apparatus 3 of this embodiment calculates the power conversion efficiency (eta) in the power supply circuit 2, controls the several power conversion part 26 based on the calculated power conversion efficiency (eta), and drives individually The power conversion efficiency η is improved by executing the control for switching between the state and the stop state.

  Here, “power conversion efficiency η” represents the efficiency with which the input / output power is converted in the power supply circuit 2. The power conversion efficiency η of the power supply circuit 2 typically corresponds to the power conversion efficiency η of the entire power supply circuit 2 by the power conversion unit 26 in the driving state except for the power conversion unit 26 in the stopped state. The power conversion efficiency η is, for example, the ratio between the input power and the output power of the power supply circuit 2, and can be expressed by η = Pout / Pin × 100 [%] where Pin is the input power and Pout is the output power. . The power conversion efficiency η is more efficient as it approaches 100%, and the internal loss is reduced. For example, as shown in FIGS. 3 and 4, the power conversion efficiency η tends to vary according to the temperature, the load factor, and the like in the power supply circuit 2.

  In FIG. 3, the horizontal axis represents temperature, and the vertical axis represents power conversion efficiency η of the power supply circuit 2. As shown in FIG. 3, for example, the power conversion efficiency η tends to decrease as the temperature of the power conversion unit 26 (for example, the temperature of each transistor 23) increases relatively.

  In FIG. 4, the horizontal axis is the load factor, and the vertical axis is the power conversion efficiency η of the power supply circuit 2. Here, the “load factor” represents the ratio of the current (load current) flowing through the power supply circuit 2 to the rated current (A) (or the ratio of the load capacity to the rated output capacity (W)) as a percentage. That is, the state where the load factor is 100% means a state where the rated current flows through the power supply circuit 2. Furthermore, the load factor of the power conversion unit 26 in the driving state typically corresponds to the load factor of each transistor 23 that is a switching element of the power conversion unit 26 in the driving state. Here, since the transistors 23 are electrically provided in parallel, basically, the load factors of the transistors 23 of the power conversion unit 26 in the driving state are substantially equal. The load factor of each power conversion unit 26 in the driving state is relatively lower as the number of power conversion units 26 in the driving state is relatively larger, and the number of power conversion units 26 in the driving state is relatively lower. The smaller the number, the higher the tendency.

  As shown in FIG. 4, the power conversion efficiency η increases as the load factor gradually increases from a state where the load factor of each power conversion unit 26 in the driving state is relatively low, and reaches a peak. After passing (maximum value), it tends to decrease gradually. That is, the power conversion efficiency η typically has a relatively low number of power conversion units 26 in the drive state in the region on the low load factor side with the load factor at which the power conversion efficiency η reaches a peak as a boundary. It tends to become relatively higher as the load factor becomes lower and the load factor becomes higher. On the other hand, the power conversion efficiency η typically has a relatively high number of power conversion units 26 in a driving state in a region on the high load factor side with a load factor at which the power conversion efficiency η reaches a peak as a boundary. It tends to become higher as the load increases and the load factor becomes lower. For example, when the load ratio of the power conversion unit 26 in the driving state is too high, the control IC 31 increases the ON resistance of each transistor 23 in each power conversion unit 26 by increasing the number of the power conversion units 26 in the driving state. Can be reduced, and conduction loss can be suppressed. Thereby, the control IC 31 can suppress the heat loss by suppressing the conduction loss by relatively reducing the current flowing through each transistor 23, for example, thereby suppressing the temperature rise and improving the power conversion efficiency η. Can do.

  The control IC 31 of the present embodiment controls the plurality of power conversion units 26 based on the above-described tendency of the power conversion efficiency η, and performs control for switching between the driving state and the stopped state (hereinafter simply referred to as “switching control”). ”). The control IC 31 calculates the power conversion efficiency η of the power supply circuit 2, selects the power conversion unit 26 to be driven based on the calculated power conversion efficiency η, and determines the number of power conversion units 26 in the drive state. By adjusting, the load factor of each power conversion unit 26 is adjusted, and thereby the optimum power conversion efficiency η is realized in the entire power supply circuit 2.

  Furthermore, the control IC 31 according to the present embodiment controls the plurality of power conversion units 26 based on the load factor of the power conversion unit 26 in the drive state, and executes control for individually switching between the drive state and the stop state. Thus, the power conversion efficiency η is improved more suitably. That is, the control IC 31 performs switching control of the power conversion unit 26 based on the power conversion efficiency η of the power supply circuit 2 and the load factor of the power conversion unit 26 in the driving state.

  Hereinafter, a specific example of the switching control of the power conversion unit 26 by the control IC 31 will be described with reference to FIG. In the following description, the state in which the number of power conversion units 26 in the drive state is relatively small is a single converter in which the first power conversion unit 26a is in the drive state and the second power conversion unit 26b is in the stop state. It will be described as being in a state. On the other hand, the state where the number of power conversion units 26 in the drive state is relatively large is described as a dual converter state in which both the first power conversion unit 26a and the second power conversion unit 26b are in the drive state. To do. That is, in the switching power supply 1, when power conversion is performed in the power supply circuit 2, the first power conversion unit 26a is basically maintained in the driving state (SW1 and SW2 are in the on state), and then the power Based on the power conversion efficiency η of the circuit 2 and the load factor of the power conversion unit 26 in the driving state, the state of the second power conversion unit 26b is switched.

  The control IC 31 has a load factor of the power conversion unit 26 in the drive state in a state where the number of the power conversion units 26 in the drive state is relatively small is equal to or higher than a predetermined load determination threshold value Th11 for driving determination, and When the power conversion efficiency η of the power supply circuit 2 is less than the preset drive determination efficiency prescribed value Th21 (for example, when it corresponds to the operating point A in FIG. 4), the number of the power conversion units 26 in the drive state is relative To increase. That is, in the single converter state, the control IC 31 has the load factor of the first power conversion unit 26a equal to or greater than the drive determination load factor prescribed value Th11, and the power conversion efficiency η of the power supply circuit 2 is the drive decision efficiency prescribed value Th21. If it is less, the switches SW3 and SW4 of the switching device 32 are turned on. Thereby, the control IC 31 sets the second power conversion unit 26b in the drive state in addition to the first power conversion unit 26a, and switches to the dual converter state. Here, the drive determination load factor prescribed value Th11 is a threshold value set in advance with respect to the load factor of the power conversion unit 26. For example, according to the characteristics of the load factor and power conversion efficiency in the power supply circuit 2 Is a preset value. The drive determination load factor prescribed value Th11 is typically higher than a load factor at which the power conversion efficiency η reaches a peak (that is, a value in a region where the power conversion efficiency η deteriorates as the load factor increases). Is set. The drive determination efficiency prescribed value Th21 is a threshold value set in advance with respect to the power conversion efficiency η, and is a value set in advance according to, for example, the characteristics of the load factor and power conversion efficiency in the power supply circuit 2 or the like. is there. The drive determination efficiency prescribed value Th21 is typically set based on an allowable power conversion efficiency η or the like. As a result, the power supply circuit 2 can improve the power conversion efficiency η because the number of power conversion units 26 in the driving state is relatively large and the load factor in each power conversion unit 26 is relatively low. .

  Even if the load factor of the power conversion unit 26 in the drive state with the relatively small number of the power conversion units 26 in the drive state is equal to or greater than the drive determination load factor prescribed value Th11, the control IC 31 When the power conversion efficiency η is equal to or greater than the drive determination efficiency prescribed value Th21 (for example, when it corresponds to the operating point B in FIG. 4), the power conversion efficiency η does not drop so much. The number of conversion units 26 is kept relatively small. Further, the control IC 31 has a case where the load factor of the power conversion unit 26 in the drive state with a relatively small number of the power conversion units 26 in the drive state is less than the drive determination load factor prescribed value Th11 (for example, FIG. 4). If the number of driving power conversion units 26 is further reduced and the load factor cannot be increased, the number of driving power conversion units 26 is relatively small. Keep it. That is, in the single converter state, the control IC 31 has the load factor of the first power conversion unit 26a equal to or greater than the drive determination load factor prescribed value Th11, and the power conversion efficiency η of the power supply circuit 2 is the drive decision efficiency prescribed value Th21. In the case of the above, or when the load factor of the first power converter 26a is less than the drive determination load factor prescribed value Th11, the single converter state is maintained as it is.

  The control IC 31 has a load factor of the power conversion unit 26 in the drive state in a state where the number of the power conversion units 26 in the drive state is relatively large, and is less than a preset load determination threshold value Th12 for stop determination, and When the power conversion efficiency η of the power supply circuit 2 in the drive state is less than the preset stop determination efficiency prescribed value Th22 (for example, corresponding to the operating point D in FIG. 4), the drive state power conversion unit 26 Reduce the number of In other words, in the dual converter state, the control IC 31 has a load factor of the first power conversion unit 26a and the second power conversion unit 26b that is less than the stop determination load factor prescribed value Th12, and the power conversion efficiency η of the power supply circuit 2 is If it is less than the stop determination efficiency prescribed value Th22, the switches SW3 and SW4 of the switching device 32 are turned off. As a result, the control IC 31 stops the second power conversion unit 26b and switches to the single converter state. Here, the stop determination load factor prescribed value Th12 is a threshold value set in advance with respect to the load factor of the power conversion unit 26. For example, according to the characteristics of the load factor and the power conversion efficiency in the power supply circuit 2 Is a preset value. The stop determination load factor prescribed value Th12 is typically a value higher than the load factor at which the power conversion efficiency η peaks (that is, a value in a region where the power conversion efficiency η deteriorates as the load factor increases). (Hysteresis α will be described later). The stop determination efficiency prescribed value Th22 is a threshold value set in advance with respect to the power conversion efficiency η, and is a value set in advance according to, for example, the characteristics of the load factor and the power conversion efficiency in the power supply circuit 2. is there. The stop determination efficiency prescribed value Th22 is typically set based on the allowable power conversion efficiency η, the peak of the power conversion efficiency η, and the like (the hysteresis β will be described later). As a result, the power supply circuit 2 can improve the power conversion efficiency η because the number of the power conversion units 26 in the drive state is relatively small and the load factor in each power conversion unit 26 is relatively high. .

  Even if the load factor of the power conversion unit 26 in the drive state with the relatively large number of power conversion units 26 in the drive state is less than the stop determination load factor prescribed value Th12, the control IC 31 When the power conversion efficiency η is equal to or greater than the stop determination efficiency prescribed value Th22 (for example, when it corresponds to the operating point E in FIG. 4), the power conversion efficiency η is in a good state. The number of the parts 26 is maintained in a relatively large state. In addition, the control IC 31 has a case where the load factor of the power conversion unit 26 in the drive state in a state where the number of the power conversion units 26 in the drive state is relatively large is greater than or equal to the stop determination load factor prescribed value Th12 (for example, FIG. If the number of driving power converters 26 is further increased and the load factor cannot be lowered, the number of driving power converters 26 is relatively large. Keep it. In other words, in the dual converter state, the control IC 31 has a load factor of the first power conversion unit 26a and the second power conversion unit 26b that is less than the stop determination load factor prescribed value Th12, and the power conversion efficiency η of the power supply circuit 2 is When it is equal to or greater than the stop determination efficiency prescribed value Th22, or when the load factor of the first power converter 26a and the second power converter 26b is equal to or greater than the stop decision load factor prescribed value Th12, the dual converter state is maintained. To maintain.

  In the switching control by the control IC 31 of the present embodiment, the hysteresis α is set for the drive determination load factor prescribed value Th11 and the stop decision load factor prescribed value Th12, thereby suppressing the occurrence of hunting. ing. Here, the stop determination load factor prescribed value Th12 is set to a value smaller by the hysteresis α than the drive decision load factor prescribed value Th11. Further, the hysteresis β is set for the drive determination efficiency specified value Th21 and the stop determination efficiency specified value Th22, thereby suppressing the occurrence of hunting. Here, the stop determination efficiency specified value Th22 is set to a value larger by the hysteresis β than the drive determination efficiency specified value Th21. The hysteresis α, β may be arbitrarily set in advance.

  Next, an example of switching control of the power conversion unit 26 by the control IC 31 will be described with reference to the flowchart of FIG. These control routines are repeatedly executed at a control cycle (clock unit) every several ms to several tens of ms.

  First, the control IC 31 acquires information related to the input voltage, input current, output voltage, output current, load factor, and the like of the power supply circuit 2 by regular monitoring (step ST1).

  Next, the control IC 31 calculates an actual measurement value of the power conversion efficiency η of the power supply circuit 2 based on the information acquired in step ST1 (input voltage, input current, output voltage, output current, etc. of the power supply circuit 2). Processing is performed (step ST2).

  Next, the control IC 31 determines whether or not the area B, that is, the second power conversion unit 26b is stopped (step ST3).

  When the control IC 31 determines that the area B, that is, the second power conversion unit 26b is stopped, in other words, determines that it is in the single converter state (step ST3: Yes), the information acquired in step ST1. Based on (load factor), it is determined whether or not the load factor of the power conversion unit 26 in the drive state is equal to or greater than the drive determination load factor prescribed value Th11 (step ST4).

  When the control IC 31 determines that the load factor of the power conversion unit 26 in the drive state is equal to or greater than the drive determination load factor prescribed value Th11 (step ST4: Yes), the power conversion efficiency of the power supply circuit 2 calculated in step ST2 It is determined whether or not η is less than the drive determination efficiency prescribed value Th21 (step ST5).

  When the control IC 31 determines that the power conversion efficiency η of the power supply circuit 2 is less than the drive determination efficiency prescribed value Th21 (step ST5: Yes), the control IC 31 turns on the switches SW3 and SW4 of the switching device 32, and the area B, Then, the second power conversion unit 26b is switched to the dual converter state with the drive state (step ST6), the present control flow is terminated, and the process returns to step ST1.

  When the control IC 31 determines in step ST4 that the load factor of the power conversion unit 26 in the drive state is less than the drive determination load factor prescribed value Th11 (step ST4: No), in step ST5, the power supply circuit When it is determined that the power conversion efficiency η of 2 is equal to or greater than the drive determination efficiency prescribed value Th21 (step ST5: No), the present control flow ends in the single converter state, and the process returns to step ST1.

  When the control IC 31 determines in step ST3 that the area B, that is, the second power conversion unit 26b is being driven, in other words, if the control IC 31 determines that it is in the dual converter state (step ST3: No), the step Based on the information (load factor) acquired in ST1, it is determined whether or not the load factor of the power conversion unit 26 in the driving state is less than the stop determination load factor prescribed value Th12 (Th12 = Th11−α) ( Step ST7).

  When the control IC 31 determines that the load factor of the power converter 26 in the driving state is less than the stop determination load factor prescribed value Th12 (step ST7: Yes), the power conversion efficiency of the power supply circuit 2 calculated in step ST2 It is determined whether or not η is less than the stop determination efficiency prescribed value Th22 (Th22 = Th21−β) (step ST8).

  When the control IC 31 determines that the power conversion efficiency η of the power supply circuit 2 is less than the stop determination efficiency prescribed value Th22 (step ST8: Yes), the control IC 31 turns off the switches SW3 and SW4 of the switching device 32, so that the area B, Then, the second power conversion unit 26b is stopped and switched to the single converter state (step ST9), the present control flow is terminated, and the process returns to step ST1.

  When the control IC 31 determines in step ST7 that the load factor of the power conversion unit 26 in the drive state is equal to or greater than the stop determination load factor prescribed value Th12 (step ST7: No), in step ST8, the power supply circuit When it is determined that the power conversion efficiency η of 2 is equal to or greater than the stop determination efficiency prescribed value Th22 (step ST8: No), the present control flow is terminated in the dual converter state, and the process returns to step ST1.

  According to the switching power supply 1 described above, a plurality of switching-type power conversion units that can be individually switched between a driving state in which the input voltage Vin is converted and the output voltage Vout is generated and a stop state in which power conversion is stopped. 26, the power conversion efficiency η of the power supply circuit 2 is calculated, the plurality of power conversion units 26 are controlled based on the calculated power conversion efficiency η, and the drive state and the stop state are individually set. And a control device 3 capable of executing switching control.

  Therefore, the switching power supply 1 calculates the power conversion efficiency η of the power supply circuit 2 by the control device 3, and controls to individually switch the driving state / stopped state of each power conversion unit 26 based on the calculated power conversion efficiency η. Therefore, the state of each power conversion unit 26 can be switched so that the actual power conversion efficiency η is optimal. As a result, the switching power supply 1 can improve the power conversion efficiency η. The switching power supply 1 operates in a wide range from a small capacity (at a small current) to a large capacity (at a large current), and performs high-efficiency power conversion, for example, regardless of the load size of the electrical equipment. It can be carried out.

  More specifically, according to the switching power supply 1 described above, the control device 3 further controls the plurality of power conversion units 26 based on the load factor of the power conversion unit 26 in the drive state, and individually Control for switching between a driving state and a stopped state can be executed. Therefore, since the control device 3 performs the switching control of each power conversion unit 26 based on the power conversion efficiency η of the power supply circuit 2 and the load factor of the power conversion unit 26 in the driving state, The state can be optimized quickly and with high accuracy, and the power conversion efficiency η can be improved more suitably.

  Specifically, according to the switching power supply 1 described above, the control device 3 has a load factor of the power conversion unit 26 in the drive state in a state where the number of the power conversion units 26 in the drive state is relatively small in advance. When the power determination efficiency η of the power supply circuit 2 is equal to or higher than the set drive determination load factor prescribed value Th11 and less than the preset drive decision efficiency prescribed value Th21, the drive state power conversion unit 26 Increase the number relatively. The control device 3 is configured such that the load factor of the power conversion unit 26 in the drive state in a state where the number of the power conversion units 26 in the drive state is relatively large is less than a preset load determination threshold value Th12 for stop determination, and When the power conversion efficiency η of the power supply circuit 2 in the driving state is less than the preset stop determination efficiency prescribed value Th22, the number of the power conversion units 26 in the driving state is relatively reduced. Therefore, the switching power supply 1 is in the drive state when the number of the power conversion units 26 in the drive state is relatively small and the load factor of the power conversion unit 26 is too high and the power conversion efficiency η is deteriorated. By relatively increasing the number of power conversion units 26, the load factor in each power conversion unit 26 can be suppressed and the power conversion efficiency η can be improved. The switching power supply 1 is in a driving state when the number of the power conversion units 26 in the driving state is relatively large and the load factor of the power conversion unit 26 is too low and the power conversion efficiency η is deteriorated. By relatively reducing the number of power conversion units 26, the load factor in each power conversion unit 26 can be increased, and the power conversion efficiency η can be improved.

  Further, according to the switching power supply 1 described above, the hysteresis α is set at least for the drive determination load factor prescribed value Th11 and the stop decision load factor prescribed value Th12. Therefore, the switching power supply 1 can suppress the occurrence of hunting in the switching control of the power conversion unit 26 and can suppress the fluttering of the control. It is possible to suppress frequent switching in a short period.

  In the above description, the switching power supply 1 has basically been described on the assumption that when the power conversion is performed in the power supply circuit 2, the first power conversion unit 26a is maintained in the driving state. When the first power conversion unit 26a fails, the first power conversion unit 26a may be stopped and the second power conversion unit 26b may be driven. For example, the control IC 31 determines the failure of the first power conversion unit 26a based on the input voltage, input current, output voltage, output current, and the like of the power supply circuit 2. When the control IC 31 detects that the first power conversion unit 26a is out of order, the switches SW3 and SW4 of the switching device 32 are turned on to turn on the second power conversion unit 26b, and the switching is performed. The switches SW1 and SW2 of the device 32 are turned off and the first power converter 26a is stopped. In this case, the switching power supply 1 can continue the minimum power conversion by the second power conversion unit 26b even if the first power conversion unit 26a fails, and the converter function is completely stopped. This can be suppressed.

[Embodiment 2]
FIG. 6 is a block diagram illustrating an example of a schematic configuration of a control device for a switching power supply according to the second embodiment. FIG. 7 is a flowchart illustrating an example of switching control by the switching power supply control device according to the second embodiment. FIG. 8 is a flowchart illustrating another example of the switching control by the switching power supply control device according to the second embodiment. FIG. 9 is a flowchart illustrating an example of notification control by the switching power supply control device according to the second embodiment. The switching power supply according to the second embodiment is further different from the first embodiment in that the control device is connected to the host ECU. In addition, about the structure, operation | movement, and effect which are common in embodiment mentioned above, the overlapping description is abbreviate | omitted as much as possible. For the configuration of each part of the switching power supply, refer to FIG. 1 as appropriate.

  The switching power supply 201 of this embodiment includes a power supply circuit 2 and a control device 203 (see FIG. 1 and the like). The power supply circuit 2 has the same configuration as the power supply circuit 2 described in the switching power supply 1. Further, as shown in FIG. 6, the control device 203 includes the control IC 31, the switching device 32, and the driver IC 33, and is the same configuration as the control device 3 described in the switching power supply 1.

  The control device 203 of the present embodiment is connected to a host ECU (Electronic Control Unit) 300 and can exchange information with each other. The host ECU 300 is connected to the output terminal 22 and controls driving of an electric device to which electric power is supplied from the switching power supply 201. For example, when the switching power supply 201 is mounted on a vehicle, the host ECU 300 corresponds to an ECU that controls each part of the vehicle.

  And the control apparatus 203 of this embodiment acquires the load information of the electric equipment to which the electric power converted by the power supply circuit 2 is supplied from the host ECU 300, and controls the plurality of power conversion units 26 based on the load information. In addition, it is possible to execute control for individually switching between the driving state and the stopped state.

  Specifically, the host ECU 300 is connected to the control IC 31 of the control device 203. The control IC 31 acquires the load information of the electric device from the host ECU 300, for example, predicts future load fluctuations, and performs switching control of the power conversion unit 26 based on the prediction. In other words, the control IC 31 acquires the load information of the electric device from the host ECU 300, and performs switching control of the power conversion unit 26 in anticipation of future load fluctuations.

  In this case, in the determination of the load factor in the switching control of the power conversion unit 26, the control IC 31 may reflect the load fluctuation predicted based on the load information of the electric equipment on the load factor of the power conversion unit 26. Good.

  FIG. 7 is a flowchart illustrating an example of the switching control reflecting the load information of the electric device. In the description of FIG. 7, steps ST2, ST3, ST5, ST6, ST8, and ST9 are the same as those in FIG.

  In this case, the control IC 31 first acquires information on the input voltage, input current, output voltage, output current, load factor, and the like of the power supply circuit 2 by regular monitoring. Then, the control IC 31 acquires the load information of the electric device from the host ECU 300, predicts the future load fluctuation, and calculates the predicted value of the load factor of the power conversion unit 26 based on the predicted load fluctuation ( Step ST201) and the process proceeds to step ST2.

  If the control IC 31 determines in step ST3 that it is in the single converter state (step ST3: Yes), the control IC 31 is in the drive state based on the information (predicted value of the load factor) acquired and calculated in step ST201. It is determined whether or not the predicted load factor of the power conversion unit 26 is equal to or greater than the drive determination load factor prescribed value Th11 (step ST204), and the subsequent processing is performed. Similarly, if the control IC 31 determines in step ST3 that it is in the dual converter state (step ST3: No), the control IC 31 switches to the drive state based on the information (predicted value of the load factor) acquired and calculated in step ST201. It is determined whether or not the predicted value of the load factor of a certain power converter 26 is less than the stop determination load factor prescribed value Th12 (step ST207), and the subsequent processing is performed.

  Therefore, since the control IC 31 can perform the switching control based on the predicted value of the load factor of the power conversion unit 26 in anticipation of future load fluctuations, for example, before the load on the electric device greatly increases, The plurality of power converters 26 can be controlled to increase the number of power converters 26 in the drive state to be in a dual converter state. Thereby, the switching power supply 201 can prepare for the increase of the said load by increasing the number of the power conversion parts 26 of a drive state previously with respect to the load increase of an electric equipment.

  As described with reference to FIG. 7, the control IC 31 is not limited to the method of performing the switching control by reflecting the load information of the electric device in the load factor, and responds to the load fluctuation predicted based on the load information of the electric device. Thus, the switching control may be performed directly. For example, the control IC 31 controls the plurality of power conversion units 26 in advance before the load actually increases when the load of the electric device is expected to increase in the future based on the load information of the electric device. The number of the power conversion units 26 in the driving state is relatively increased to obtain a dual converter state. Thereby, the switching power supply 201 can prepare for the increase of the said load by increasing the number of the power conversion parts 26 of a drive state previously with respect to the load increase of an electric equipment. Similarly, when it is expected that the load on the electric device will decrease in the future, the control IC 31 controls the plurality of power conversion units 26 in advance before the load actually decreases, so that the power conversion unit 26 in the driving state is controlled. Reduce the number to a single converter state. Thereby, the switching power supply 201 can prepare for the reduction of the load by reducing the number of the power conversion units 26 in the driving state in advance with respect to the reduction of the load of the electric device. Note that, as described above, the control for setting the single converter state in preparation for the load reduction of the electric device is performed in a range that can satisfy the electric power required by the electric load.

  In this case, the control IC 31 may perform control as shown in FIG. 8, for example, as a routine different from the control of FIG.

  In the control of FIG. 8, the control IC 31 first determines whether or not the area B, that is, the second power conversion unit 26b is stopped (step ST301).

  When the control IC 31 determines that the area B, that is, the second power conversion unit 26b is stopped, in other words, determines that it is in the single converter state (step ST301: Yes), the electric power acquired from the host ECU 300 is obtained. Based on the load information of the device, it is determined whether or not the load of the electric device is expected to become larger than a predetermined value in the future (step ST302). Here, the predetermined value is a threshold value set in advance for the load of the electric device, and is set according to the capacity of each power conversion unit 26 and the like. If the control IC 31 determines that the load on the electrical device does not become greater than the predetermined value (step ST302: No), the control IC 31 ends the control flow and returns to step ST301.

  When the control IC 31 determines that the load on the electrical device is expected to be greater than the predetermined value (step ST302: Yes), the control IC 31 turns on the switches SW3 and SW4 of the switching device 32, and turns on the area B, that is, the second power conversion unit 26b. Is switched to the dual converter state (step ST303), this control flow is terminated, and the process returns to step ST301.

  When the control IC 31 determines in step ST301 that the area B, that is, the second power conversion unit 26b is being driven, in other words, the control IC 31 determines that it is in the dual converter state (step ST301: No), Based on the load information of the electric device acquired from the ECU 300, it is determined whether or not the load of the electric device is expected to be a predetermined value or less in the future (step ST304). If the control IC 31 determines that the actual load on the electrical device is not less than or equal to the predetermined value (step ST304: No), the control IC 31 ends this control flow and returns to step ST301.

  When the control IC 31 determines that the load on the electrical device is expected to be equal to or less than the predetermined value (step ST304: Yes), the control IC 31 turns off the switches SW3 and SW4 of the switching device 32, and the area B, that is, the second power conversion unit 26b. Is switched to a single converter state (step ST305), this control flow is terminated, and the process returns to step ST301.

  Note that when the control IC 31 according to the present embodiment detects an abnormality such as a failure of the first power conversion unit 26a, the control power supply 31a stops the first power conversion unit 26a as described above, and the second power conversion unit 26a While the conversion unit 26b is in a driving state, the host ECU 300 may be notified that an abnormality has occurred in a part of the power conversion unit 26. An example of the flow in this case is shown in FIG.

  In the control of FIG. 9, the control IC 31 determines whether an abnormality such as a failure of the power conversion unit 26 has occurred based on, for example, the input voltage, input current, output voltage, output current, and the like of the power supply circuit 2. (Step ST401). If it is determined that no abnormality has occurred (step ST401: No), the control IC 31 ends this control flow and returns to step ST401. When it is determined that an abnormality has occurred (abnormal) (step ST401: Yes), the control IC 31 notifies the host ECU 300 that an abnormality has occurred in a part of the power conversion unit 26 (step ST402). This control flow is ended, and the process returns to step ST401. Then, when the host ECU 300 receives a notification from the control IC 31 that an abnormality has occurred in a part of the power conversion unit 26, for example, the upper ECU 300 may perform upper limit restriction on the load of the electrical device.

  The switching power supply 201 described above calculates the power conversion efficiency η of the power supply circuit 2 by the control device 3, and individually determines the driving state / stopped state of each power conversion unit 26 based on the calculated power conversion efficiency η. Since the switching control is executed, the state of each power conversion unit 26 can be switched so that the actual power conversion efficiency η is optimized. As a result, the switching power supply 201 can improve the power conversion efficiency η.

  Furthermore, according to the switching power supply 201 described above, the control device 3 acquires the load information of the electrical equipment to which the power converted by the power supply circuit 2 is supplied, and a plurality of power conversion units based on the load information. 26 can be controlled to switch between a driving state and a stopped state individually. Therefore, the switching power supply 201 can perform switching control of the power conversion unit 26 in anticipation of future load fluctuations. Thereby, for example, the switching power supply 201 can increase the number of the power conversion units 26 in the driving state in advance with respect to an increase in the load of the electric equipment, and can prepare for the increase in the load. In addition, the number of the power conversion units 26 in the drive state can be reduced in advance with respect to the load reduction of the electric equipment, and the load can be reduced. As a result, the switching power supply 201 can suppress the power conversion efficiency η from temporarily deteriorating with respect to fluctuations in the load of the electrical equipment, and thus can improve the power conversion efficiency η.

  The switching power supply according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. The switching power supply according to the present embodiment may be configured by appropriately combining the components of the embodiments and modifications described above.

  In the above description, the power supply circuit 2 has been described as a switching step-down DC-DC converter circuit. However, the power supply circuit 2 is not limited thereto, and may be, for example, a switching step-up DC-DC converter circuit. However, it may be another circuit including a switching element. In addition, the power supply circuit 2 may be configured to include an input terminal to which the input voltage Vin is supplied from another power supply circuit or the like instead of the DC power supply. For example, the power supply circuit 2 is an AC-DC converter circuit. It may be incorporated in the part.

  Further, the control IC 31 may simply compare the load factors described above based on the load current value. Further, for example, the control IC 31 can omit the switches SW1 and SW2 by making the wiring resistance of the area A corresponding to the first power conversion unit 26a equal to that of the other area B.

  In the above description, the plurality of transistors 23 has been described as having a total of eight transistors 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h. Alternatively, it may be 7 or less if at least 2 or more. Although the plurality of power conversion units 26 has been described as being two of the first power conversion unit 26a and the second power conversion unit 26b, the present invention is not limited to this and may be three or more. In the above description, the first power conversion unit 26a and the second power conversion unit 26b are described as including four transistors 23. However, the present invention is not limited to this, and at least one or more of each is included. The transistor 23 may be included. Further, the first power conversion unit 26a and the second power conversion unit 26b may not have the same number of transistors 23 (in other words, power conversion capacity), and one is relatively small and the other is relatively large. It may be a configuration. That is, the power supply circuit 2 only needs to include at least a plurality of power conversion units 26, and the number of switching elements (transistors 23) mounted in each power conversion unit 26 (each area) is a circuit that drives the switching elements, Alternatively, any number may be used as long as it is within the specification of the switching element.

  In the above description, it is assumed that the control IC 31 can control the plurality of power conversion units 26 on the basis of the power conversion efficiency η and the load factor, and can perform control for individually switching between the drive state and the stop state. However, the plurality of power conversion units 26 may be controlled based on the power conversion efficiency η regardless of the load factor, and control for individually switching between the drive state and the stop state may be executed. In this case, the control IC 31 sets, for example, the optimum target power conversion efficiency ηt in advance, and the power conversion unit in the drive state so that the actually measured power conversion efficiency η converges to the target power conversion efficiency ηt. The switching control of the power conversion unit 26 may be executed by feedback control that adjusts the number 26.

  In the above description, the drive determination load factor specified value Th11 and the stop determination load factor specified value Th12 have been described as having the hysteresis α, but the present invention is not limited thereto. That is, [Hysteresis α = 0] and [Drive determination load factor prescribed value Th11 = Stop decision load factor prescribed value Th12] may be used. Similarly, the drive determination efficiency specified value Th21 and the stop determination efficiency specified value Th22 have been described as having the hysteresis β, but are not limited thereto. That is, [hysteresis β = 0] and [driving determination efficiency prescribed value Th21 = stop judging efficiency prescribed value Th22] may be used.

1, 201 Switching power supply 2 Power supply circuit 3, 203 Controllers 23, 23a, 23b, 23c, 23d, 23e, 23f, 23g, 23h Transistor 26 Power converter 31 Control IC
300 host ECU

Claims (3)

A power supply circuit having a plurality of power conversion units of a switching method that can be individually switched between a driving state that converts an input voltage and generates an output voltage and a stopped state that stops power conversion;
The power conversion efficiency of the power supply circuit is calculated, and the plurality of power conversion units are controlled based on the calculated power conversion efficiency and the load factor of the power conversion unit in the driving state, and individually in the driving state And a control device capable of executing control to switch between the stopped states ,
The controller is
A load factor of the power conversion unit in the driving state in a state where the number of the power conversion units in the driving state is relatively small is equal to or higher than a predetermined load determination load factor for determination, and the power supply circuit When the power conversion efficiency of the drive conversion efficiency is less than a preset drive determination efficiency prescribed value, relatively increase the number of the power conversion unit in the drive state,
Even if the load factor of the power conversion unit in the drive state with a relatively small number of the power conversion units in the drive state is equal to or greater than the drive determination load factor prescribed value, the power conversion of the power supply circuit When the efficiency is equal to or higher than the drive determination efficiency prescribed value, the number of the power conversion units in the drive state is maintained in a relatively small state,
The power conversion in the driving state when the load factor of the power conversion unit in the driving state is less than the drive determination load factor prescribed value in a state where the number of the power conversion units in the driving state is relatively small Keep the number of parts relatively small,
The load ratio of the power conversion unit in the drive state in a state where the number of the power conversion units in the drive state is relatively large is less than a preset load determination threshold value for stop determination, and the drive state When the power conversion efficiency of the power supply circuit is less than a preset efficiency determination value for stop determination, the number of the power conversion units in the driving state is relatively reduced,
Even if the load factor of the power conversion unit in the drive state in a state where the number of the power conversion units in the drive state is relatively large is less than the specified load factor for stop determination, the power of the power supply circuit When the conversion efficiency is equal to or higher than the stop determination efficiency prescribed value, the number of the power conversion units in the driving state is maintained in a relatively large state,
The power conversion in the drive state when the load factor of the power conversion unit in the drive state is greater than or equal to the specified load factor for stop determination in a state where the number of the power conversion units in the drive state is relatively large It is characterized by maintaining a relatively large number of parts ,
Switching power supply. The drive determination load factor specified value and the stop determination load factor specified value are set with hysteresis,
The switching power supply according to claim 1 . The control device acquires load information of an electric device to which power converted by the power supply circuit is supplied, controls the plurality of power conversion units based on the load information, and individually controls the driving state and the stop Control to switch between states can be executed,
The switching power supply according to claim 1 or 2 .

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