JP6326967B2 - Multi-phase power supply - Google Patents

Description

  The present invention relates to a multiphase power supply apparatus.

  In recent years, portable terminals have been required to be more compact and smaller in size as the required power increases as performance and functionality increase. For this reason, a synchronous rectification type DC / DC converter (hereinafter referred to as a converter) mounted on a portable terminal device is required to be even smaller, handle a large amount of power, and be highly efficient.

For this reason, multi-phase power supply devices that operate a plurality of converters in parallel have been developed.
In this multiphase power supply device, the output current ripple can be reduced by adding the output current obtained by shifting the switching timing of the converters connected in parallel at equal time intervals. For this reason, there is an advantage that the passive element on the output side can be easily downsized.

  Further, by connecting the converters in parallel, heat loss can be distributed to each converter, and there is an advantage that the requirement of heat dissipation performance for the converter is eased and the converter can be easily downsized.

  In the case of light load driving (when driving various circuit units with low current consumption), it is possible to improve the overall power conversion efficiency by pausing several of the converters. This also has the advantage of maintaining high efficiency over a wide range of loads from light loads to heavy loads.

  This multi-phase power supply device is known to have a configuration including a dedicated control unit and a plurality of drive units. In this case, multi-phase operation is possible by appropriately changing the phase waveform state of the drive waveform output from each control unit. However, the mounting area increases as the dedicated control unit is mounted, which makes it difficult to reduce the size of the multiphase power supply apparatus.

  In addition, there are known multiphase power supply apparatuses that do not have a dedicated control unit but have only a plurality of drive units. In this case, since the control unit is not provided, it is possible to reduce the size accordingly.

  In a multi-phase power supply device that does not have this control unit, there is no particular problem if the number of operating phases (the number of operating phases or the number of operating converters) is fixed. A function of switching the number of converters that operate according to the operating environment is provided (see, for example, Patent Document 1).

  By the way, in the multi-phase power supply apparatus that does not have this control unit, each converter monitors the output current, for example, and starts its operation when the output current value exceeds the threshold value. It can be considered that the operation is stopped when the following occurs.

However, with such a configuration, when noise is superimposed on the monitored output current value, a malfunction due to the noise occurs.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multi-phase power supply apparatus that can prevent a malfunction between a hibernation state and an operation state.

  By the way, in order to prevent this malfunction, the operation start current threshold at the time of transition from the operation pause to the operation start is different from the operation stop current threshold at the time of transition from the operation to the operation stop, that is, the threshold has a hysteresis. The structure to have can be considered.

However, with such a configuration, in the entire multiphase power supply apparatus, the hysteresis threshold current increases according to the number of converters that operate.
For example, it is possible to operate four converters connected in parallel with each converter having an operation start current threshold of 0.9 A, an operation stop current threshold of 0.3 A, and a common hysteresis threshold current of each converter of 0.6 A. Consider a phase power supply.

  In this case, in the entire multiphase power supply device, when the current flowing toward the load (load current) exceeds 2.7 A, the four converters start to operate. When the load current decreases during the operation of the four converters and becomes 1.2 A or less, the operation of one converter is stopped, and the remaining three converters are switched to the operating state.

  According to this multi-power supply apparatus, once the load current becomes 2.7 A or more and the four converters start to operate, the four converters continue to operate until they become 1.2 A or less.

  Therefore, when viewed as the entire multi-phase power supply device, the distribution of the number of converters operating with respect to the load current becomes uneven, and the power conversion efficiency of the entire multi-phase power supply device is deteriorated.

  According to the embodiment of the present invention, even in such a case, the deterioration of the power conversion efficiency of the entire multiphase power supply device can be eliminated.

A multi-phase power supply device according to the present invention is configured such that a plurality of power supplies that operate as a master power supply and operate as a slave power supply and output a current in response to a load request are connected in parallel to the load. Is based on the connection state between the inflow connection terminal, the outflow connection terminal, the output information terminal, the voltage conversion unit that steps down and outputs the direct current voltage from the direct current voltage source, and the inflow connection terminal and the outflow connection terminal. A phase control unit that autonomously determines whether it is a master power supply or a slave power supply and detects the number of operation phases based on the suction current flowing into the inflow connection terminal, and the number of operation phases from the phase control unit And a switching control unit that receives the information and the output current value from the output information terminal and switches the voltage conversion unit between a resting state and an operating state,
The switching control unit has an operation start current threshold value when used as a slave power supply and an operation stop current threshold value lower than the operation start current threshold value.

  According to the present invention, it is possible to prevent a malfunction between the sleep state and the operation state of the slave power supply.

It is a block circuit diagram which shows an example of the Example of the multiphase power supply device which concerns on this invention. FIG. 2 is a circuit diagram illustrating a detailed configuration of a clock generation unit illustrated in FIG. 1. It is explanatory drawing of the state transition of each power supply. It is explanatory drawing which shows the relationship between the load current at the time of making the operation stop current threshold value of a slave power supply different, and a state transition. It is explanatory drawing which shows the relationship between a load current at the time of making the operation stop current threshold value of a slave power supply the same, and a state transition.

(Configuration of multi-phase power supply)
FIG. 1 shows a block circuit diagram of a multi-phase power supply apparatus according to an embodiment of the present invention. This multiphase power supply apparatus is composed of a plurality of multiphase power supply ICs.

  In the embodiment shown in FIG. 1, three multiphase power supply ICs are connected in parallel to the load 106. Note that a capacitor 105 constituting a part of the filter is connected to the load 106 in parallel. At least one of the three multiphase power supply ICs is used as a master power supply MA, and the remaining two are used as slave power supplies SL1 and SL2. The master power source MA is always operating when the power is turned on.

  Whether the power source is the master power source MA or the slave power sources SL1 and SL2 is determined based on whether or not an inflow connection terminal isi [n] described later is connected to the DC voltage source Vin. This determination is made by the phase control unit 111 described later.

  The master power supply MA and the slave power supplies SL1 and SL2 include a phase control unit 111, a voltage conversion unit (DC / DC unit) 101, and a DC / DC control unit (DCDC_CNT) unit 112 as a switching control unit.

  The phase control unit 111 includes a phase detection unit (PHD) 102, a phase holding unit (Hold) 103, a clock generation unit (CKG) 104, and a control (CNT) unit 110.

  The master power supply MA and slave power supplies SL1 and SL2 are a power supply voltage input terminal Vin [n], an output information terminal isen [n], a clock terminal CLK [n], an outflow connection terminal isr [n], and an inflow connection terminal isi [n]. The output voltage terminal Vout [n] is provided. However, n is an integer meaning the distinction between the multiphase power supply ICs.

  Each output voltage terminal Vout [n] is connected to a load 106 and a capacitor 105. In this embodiment, three multi-phase power supply ICs are connected in parallel to the load 106 and output current in response to a request from the load 106. In this embodiment, n is one of 1, 2, and 3.

  Note that the number of multiphase power supply ICs connected in parallel to the load 106 is not limited to this, and the multiphase power supply ICs may be connected to the load 106 alone, or two or more multiphase power supply ICs may be connected in parallel. Also good.

  The voltage conversion unit (DC / DC unit) 101 of the master power source MA and the slave power sources SL1 and SL2 is connected to the DC voltage Vin from the DC voltage source Vin (for convenience of explanation, the DC voltage source) via the power source voltage input terminal Vin [n]. Is used).

  The voltage conversion unit (DC / DC unit) 101 includes a switching circuit. The voltage conversion unit (DC / DC unit) 101 steps down the DC voltage Vin and outputs the output voltage Vout from the output voltage terminal Vout [n] toward the load 106.

  The output information terminal isen [1] of the master power source MA is connected to the output information terminals isen [2] and isen [3] of the slave power sources SL1 and SL2.

  The outflow connection terminal isr [1] of the master power source MA is connected to the inflow connection terminal isi [2] of the slave power source SL1. The outflow connection terminal isr [2] of the slave power supply SL1 is connected to the inflow connection terminal isi [3] of the slave power supply SL2.

  The outflow connection terminal isr [3] of the slave power supply SL2 is grounded. The phase detection unit (PHD) 102 detects whether or not the inflow connection terminal isi [n] is connected to the DC voltage source Vin, and the phase control unit 111 thereby determines whether or not it is the master power source MA. Determine autonomously.

  Further, the phase control unit 111 detects its own connection order (phase) based on the connection state between the inflow connection terminal isi [n] and the outflow connection terminal isr [n].

  For example, the phase detection unit (PHD) 102 of the phase control unit 111 of the master power supply MA supplies a sink current of, for example, 5 μA from the outflow connection terminal isr [1] during its operation, and the inflow connection terminal isi [2] of the slave power supply SL1. Output toward.

  The phase control unit 111 of the slave power supply SL1 autonomously determines that it is the slave power supply SL1 connected to the master power supply MA from the sink current 5 μA flowing into the phase detection unit 102 from the inflow connection terminal isi [2]. Can be recognized.

  During the operation of the slave power supply SL1, the phase detection unit (PHD) 102 adds the suction current of 5 μA to the suction current of 5 μA flowing from the master power supply MA in the previous stage, and sucks 10 μA from the outflow connection terminal isr [2]. The current is output toward the inflow connection terminal isi [3] of the slave power source SL2.

  The phase control unit 111 of the slave power supply SL2 autonomously determines that the slave power supply SL2 is connected to the slave power supply SL1 by the sink current 10 μA flowing into the phase detection unit 102 from the inflow connection terminal isi [3]. Can be recognized.

  In this embodiment, since the outflow connection terminal isr [3] of the slave power supply SL2 is grounded, a sink current of 10 μA is passed to the ground while the slave is idle, and a sink current of 15 μA is passed when the slave is operating. Is flushed to earth. These suction currents flow into the inflow connection terminal isi [1] of the master power source MA. The phase control unit 111 of the master power source MA calculates the number of operation phases by dividing the suction current.

However, if the inflow connection terminal isi [4] of the slave power supply (not shown) is connected to the outflow connection terminal isr [3] of the slave power supply SL2, a suction of 15 μA is generated during the operation of itself. The current flows into the inflow connection terminal isi [4].
In this way, each multi-phase power supply IC can autonomously recognize whether it is the master power supply MA or the slave power supply SL by the sink current.

  Information ph [n] on the number of phases detected by the phase detection unit (PHD) 102 is input to the phase holding unit (Hold) 103 and the DC / DC control unit (DCDC_CNT) unit 112.

  Based on the timing signal generated by the control (CNT) unit 110, the phase holding unit (Hold) 103 continues to hold the phase number information ph [n] and outputs it to the clock generation unit (CKG) 104.

  As shown in FIG. 2, the clock generation unit 104 includes a clock oscillator 112 ′, a two-clock input / output selector 113, a DLL (Delay Locked Loop) circuit 114, and a clock selector 115.

  Based on the master determination signal MASTER from the control unit 110, the clock generation unit 104 turns on the selector 113 to enter the master mode when it is the master. When the clock generation unit 104 is a slave, the clock generator 104 turns off the selector 113 and enters the slave mode.

  In the master mode, the clock generation unit 104 uses the reference clock from the clock oscillator 112 ′ as a voltage conversion unit (DC / DC unit) of the slave power supplies SL1 and SL2 via the selector 113 and the clock terminal CLK [n] (Ckif). 101.

The DLL circuit 114 generates a multiphase clock synchronized with the reference clock and outputs it to the selector 115.
The selector 115 selects a clock of one phase among the multiphase clocks based on the phase holding signal Lph from the phase holding unit 103 and clocks the voltage conversion unit (DC / DC unit) 101 of the master power source MA. Output via terminal Cko. The voltage conversion unit (DC / DC unit) 101 is switched based on this clock signal.

  In the slave mode, the clock generator 104 receives the clock transmitted from the master power source MA through the clock terminal CLK [n] (Ckif) and inputs it to the DLL circuit 114 via the selector 113.

  The DLL circuits 114 of the slave power supplies SL1 and SL2 generate a multiphase clock synchronized with the received clock CLK based on the received clock. The selector 115 selects a clock of one phase among the multiphase clocks based on the phase holding signal Lph, and outputs it to the voltage conversion unit (DC / DC unit) 101 via the clock terminal Cko. Since the slave power supplies SL1 and SL2 generate multiphase clocks based on the clock of the master power supply MA, the phase of each voltage conversion unit (DC / DC unit) 101 becomes a desired phase.

  That is, the clock generation unit (CKG) 104 of the master power supply MA uses the reference clock as the slave power supply SL1 via the voltage conversion unit (DC / DC unit) 101 of the master power supply MA and the clock terminals CLK [1] and CLK [2]. The voltage conversion unit (DC / DC unit) 101 and the voltage conversion unit (DC / DC unit) 101 of the slave power supply SL2 are supplied via clock terminals CLK [1] and CLK [3].

  The DC / DC control unit (DCDC_CNT) unit 112 receives the phase number information ph [n] and the output current value isen, and the DC / DC control unit (DCDC_CNT) unit 112 receives the enable signal en [n] (on / off). Signal) is output to the voltage conversion unit (DC / DC unit) 101. That is, the voltage conversion unit (DC / DC unit) 101 is switched between an operation state and an operation stop state by the enable signal en [n].

  Since the master power source MA is always operating when the power is on, the DC / DC control unit (DCDC_CNT) unit 112 sends the enable signal en [n] (on signal) to the voltage conversion unit (DC / DC unit) 101. Output.

  In this embodiment, the output current value isen is used, but a current detection signal generated in the voltage conversion unit (DC / DC unit) 101 may be used to generate the output current value isen.

  In the DC / DC control unit (DCDC_CNT) unit 112 of the slave power supplies SL1 and SL2, an output current threshold value to be compared with the output current value isen is set.

  The output current threshold includes an operation start current threshold for the slave power supply SL1 to perform a state transition from the sleep state (operation stop state) to the operation start state, and a state transition from the operation state to the sleep state (operation stop state). There is an operation stop current threshold value for performing the operation.

  By making the operation start current threshold value and the operation stop current threshold value different from each other and providing the output current value issense with hysteresis, malfunction of the voltage conversion unit (DC / DC unit) 101 of the slave power supplies SL1 and SL2 is prevented. Is prevented.

  The DC / DC control unit (DCDC_CNT) unit 112 can set the operation start current threshold value and the operation stop current threshold value in accordance with the information on the number of operation phases. A difference (hysteresis current) between the operation start current threshold and the operation stop current threshold overlapping in SL1 and SL2 can be arbitrarily set.

Thereby, it is possible to prevent a malfunction between the sleep state and the operation state of the slave power supply.
Furthermore, the number of operation phases (number of operation converters) with respect to the output current value of the multiphase power supply can be set uniformly, and the power conversion efficiency can be maximized for the entire multiphase power supply apparatus.

This will be described in detail below.
The operation start current threshold values of the slave power supplies SL1 and SL2 are set to 0.9A, the operation stop current threshold value of the slave power supply SL1 is set to 0.3A, and the operation stop current threshold value of the slave power supply SL2 is set to 0.5A. That is, the operation stop current thresholds of the slave power supplies SL1 and SL2 are different from each other.

FIG. 3 is an explanatory diagram of operation state transition of each multiphase power supply IC of the multiphase power supply device.
In FIG. 3, S0 indicates a state in which the master power source MA is active (operating) and the slave power sources SL1 and SL2 are inactive (inactive). S1 indicates that the master power source MA and the slave power source SL1 are active (in operation). The slave power supply SL2 is in a deactivated state (resting), and S2 is a state in which all of the master power supply MA and the slave power supplies SL1 and SL2 are active (operating).

Cxy represents a transition condition to each state, where x and y are either “0, 1, 2”.
In this embodiment, the condition for the state transition is as follows according to the above definition.
C00 ... isen ≦ 0.9A (operation start current threshold of slave power supply SL1)
C01 ... isen> 0.9A (operation start current threshold of slave power supply SL1)
C10 ... isen <0.3A (slave power supply SL1 operation stop current threshold)
C11... Isen ≦ 0.9 A (operation start current threshold of slave power supply SL2)
C12 ... isen> 0.9A (operation start current threshold of slave power supply SL2)
C21... Isen <0.5A (operation stop current threshold of slave power supply SL2)
C22 ... isen ≧ 0.5A (operation stop current threshold of slave power supply SL2)

  In this embodiment, when the transition condition is C00, that is, when the output current value isen of the master power supply MA is isen≤0.9A, the state S0 is realized and only the master power supply MA is active. If the load current exceeds 0.9A in state S0, isen> 0.9A, so that the transition condition C01 is established and state S1 is realized.

  That is, the master power source MA and the slave power source SL1 become active. Since master power supply MA knows the number of operation phases and slave power supply SL1 has the same output current as master power supply MA, the output current of each power supply required for load 106 is ½. As a result, the output current value isense of the master power supply MA becomes isen ≦ 0.9A.

  In the state S1, when the load current is 0.9A or more and 1.8A or less, the output current value isen of the master power supply MA is 0.3A <isen ≦ 0.9A, that is, the transition condition C11 is satisfied. Is sustained.

  In the state S1, when the load current becomes larger than 1.8A, the output current value isen of the master power source MA again becomes isen> 0.9A, that is, the transition condition C12, so that the state S2 is realized.

  As a result, the master power source MA and the slave power sources SL1 and SL2 are all active. As a result, the output currents output from the master power supply MA and the slave power supplies SL1 and SL are equalized, and the output current value isen of the master power supply MA again becomes isen ≦ 0.9A.

  In the state S2, when the load current as a whole is 1.5 A or more, the output current value isen of the master power source MA is isen ≧ 0.5 A, that is, the transition condition C22 is satisfied, and the state S2 is continued.

  In the state S2, when the load current becomes smaller than 1.5A, the output current value isen of the master power source MA becomes isen <0.5A, that is, the transition condition C21 is established, and the state S2 is changed to the state S1.

  In the state S1, when the load current is 0.6A or more, the output current value isen of the master power source MA is 0.5A> isen ≧ 0.3A, so the state S1 is continued. In the state S1, when the load current becomes 0.6A or less, the output current value isen of the master power source MA becomes isen <0.3A, that is, the transition condition C10 is established, and the state S1 is changed to the state S0.

  That is, as shown in FIG. 4, after the power source is turned on, the state S0 is continued until the load current (output current) exceeds 0.9 A, and only the master power source MA is in operation.

  In state S0, when the load current exceeds 0.9A, the output current value isen of the master power source MA becomes isen> 0.9A (transition condition C01), the state S1 is realized, and the master power source MA and the slave power source SL1 Is in operation.

  In the state S1, when the load current exceeds 1.8A, the output current value isen of the master power source MA again becomes isen> 0.9A (transition condition C12), the state S1 transits to the state S2, and the master power source MA, Slave power supplies SL1 and SL2 are in operation.

  In the state S2, when the load current becomes 1.5 A or less, the output current value isen of the master power supply MA becomes isen <0.5 A or less (transition condition C21), the state transitions from the state S2 to the state S1, and the master power supply MA and the slave While the power supply SL1 is in operation, the slave power supply SL2 is inactive.

  In the state S1, when the load current becomes 0.6A or less, the output current value isen of the master power supply MA becomes isen <0.3A or less (transition condition C10), the state S1 changes to the state S0, and the master power supply MA operates. During this time, the slave power supplies SL1 and SL2 are suspended.

  According to this embodiment, when the load current is from 0 A to 0.9 A, the operation of one multi-phase power supply IC is covered, and when the load current is from 0.6 A to 1.8 A, two multi-phase power ICs are used. Covered by the operation of the phase power supply IC, the load current from 1.5A to 3.0A is covered by the operation of the three multiphase power supply ICs, and the number of operation converters is evenly distributed to the load current. .

  In other words, in this embodiment, as indicated by hatching, the dead area HU1 between the operation stop area and the operation start area of the slave power supply SL1 that becomes active next to the master power supply MA, The insensitive area HU2 between the operation stop area and the operation start area of the slave power supply SL2 is set equal.

  In addition, by setting the operation start current threshold and a value lower than the operation start current threshold, the operation start current threshold and the operation stop current threshold are made different, and a dead region is formed between the operation start and the operation stop. Therefore, the malfunction of the slave power supplies SL1 and SL2 can be prevented, and stable control can be performed.

  Thus, according to this embodiment, the number of operation converters can be evenly distributed with respect to the load current Iout, and the power conversion efficiency in the entire multiphase power supply can be increased.

  For comparison, when the operation start current threshold value of the slave power supplies SL1 and SL2 is 0.9A, the operation stop current threshold value of the slave power supply SL1 is 0.3A, and the operation stop current threshold value of the slave power supply SL2 is 0.3A. That is, a case where the operation stop current threshold value is the same for the slave power supply SL1 and the slave power supply SL2 will be described.

  As shown in FIG. 5, since the output current value isen ≦ 0.9 A of the master power supply MA from when the power supply is turned on until the load current exceeds 0.9 A, the state S0 is continued and the master power supply MA is maintained. Only is working.

  In state S0, when the load current exceeds 0.9A, the output current value isen of the master power supply MA becomes isen> 0.9A, the state S1 is realized, and the master power supply MA and the slave power supply SL1 are in operation. .

  In the state S1, when the load current exceeds 1.8A, the output current value isen of the master power supply MA again becomes isen> 0.9A. Therefore, the state transitions from the state S1 to the state S2, and the master power supply MA and the slave power supply SL1. , SL2 is in operation.

  In the state S2, when the load current becomes 0.9A or less, the output current value isen of the master power supply MA becomes isen <0.3A or less, the state transitions from the state S2 to the state S1, and the master power supply MA and the slave power supply SL1 are operating. Then, the slave power supply SL2 is suspended.

  In the state S1, when the load current becomes 0.6A or less, the output current value isen of the master power supply MA becomes isen <0.3A or less, the state transitions from the state S1 to the state S0, and the master power supply MA is in operation. , SL2 becomes inactive.

  As described above, when the operation stop current threshold value of the slave power supply SL1 and the operation stop current threshold value of the slave power supply SL2 are set to be equal, once the transition from the state S1 to the state S2, the load current becomes three until the load current becomes 0.9A or less. The multi-phase power ICs continue to operate, and the distribution of the number of multi-phase power ICs that operate with respect to the load current becomes uneven.

  That is, in a multi-phase power supply device having a threshold current value that autonomously determines start and stop, if the threshold current value is set equal in each multi-phase power supply IC, the number of operation phases of the multi-phase power supply IC increases. The insensitive area with respect to the output current value becomes too large, the number of operations with respect to the load current becomes non-uniform, and the power conversion efficiency of the entire multiphase power supply decreases.

  On the other hand, in this embodiment, since the operation stop current threshold value of the slave power supply is made different, the number of operations with respect to the load current can be made uniform, and the power conversion efficiency in the entire multiphase power supply is improved. be able to.

MA ... Master power supply SL1, SL2 ... Slave power supply isi ... Inflow connection terminal isr ... Outflow connection terminal isen ... Output information terminal Vin ... DC voltage source 101 ... Voltage conversion unit 111 ... Phase control unit 112 ... DC / DC control unit (switching control) Part)

Patent No. 5420433

Claims (5)

A plurality of power supplies that operate as a master power supply and also operate as a slave power supply and output a current in response to a load request are connected in parallel to the load, and each power supply includes an inflow connection terminal, an outflow connection terminal, The self-master power supply or the slave power supply based on the connection state of the output information terminal, the voltage converter for stepping down and outputting the DC voltage from the DC voltage source, and the inflow connection terminal and the outflow connection terminal Phase control unit that autonomously determines whether or not and controls the number of operation phases based on the sink current flowing into the inflow connection terminal, information on the number of operation phases from the phase control unit, and output from the output information terminal A switching control unit that receives a current value and switches the voltage conversion unit between a resting state and an operating state;
The switching control unit includes an operation start current threshold value when used as a slave power supply and an operation stop current threshold value lower than the operation start current threshold value.   A slave power supply that is activated next to the master power supply, wherein at least two power supplies are connected in parallel and at least two power supply switching control units when operating as the slave power supply have different operation stop current thresholds. The dead area between the operation stop area and the operation start area is set equal to the dead area between the operation stop area and the operation start area of the slave power source that is active next to the slave power source. The multi-phase power supply device according to claim 1, wherein   The phase control unit of the master power supply operates by determining whether or not the slave power supply connected to the master power supply is in operation based on the sink current input through the inflow connection terminal. The multi-phase power supply apparatus according to claim 2, wherein the number of operating phases of the power supply is determined.   When the slave power supply of the slave power supply is not operating, the slave power supply phase control unit is connected to the subsequent stage from the outflow connection terminal with an intake current having the same magnitude as the intake current flowing in from the power supply connected to the previous stage. When the slave power supply is in operation and the slave power supply is operating, a sink current of the same magnitude as the sink current flowing from the power supply connected to the previous stage flows from the power supply connected to the previous stage. 4. The multiphase power supply device according to claim 3, wherein the multiphase power supply device is caused to flow out to an inflow connection terminal of a slave power supply connected to a subsequent stage in addition to the suction current to be generated.   The phase control unit of the master power supply includes a clock generation unit that outputs a reference clock toward the slave power supply, and the slave power supply has an output equal to the output current from the master power supply with a phase selected according to the reference clock of the master power supply The multi-phase power supply apparatus according to claim 4, wherein the multi-phase power supply apparatus is controlled to output a current.