JP2004246441A - Power supply device and power supply control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device that can accurately control and predict the time since one supply voltage reaches a desired voltage until other supply voltages reach the desired voltage in supplying a plurality of different supply voltages. <P>SOLUTION: When the power supply device 1 receives power-on instructions, a voltage control unit 11 raises a supply voltage V2 to a voltage VA 1, and also a voltage control unit 24 raises a supply voltage V3 to a reference voltage VB_STB which is lower than a reference voltage VB1. When the supply voltage V2 reaches the voltage VA1, a trigger signal TRG is generated and the voltage control unit 24 raises the supply voltage V3 from the reference voltage VB_STB to the reference voltage VB1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device and a power supply control method for supplying a plurality of different supply voltages.
[0002]
[Prior art]
In recent years, the voltage of new devices has been reduced, and devices that operate at low voltage and devices that operate at high voltage in the past have often been mixed on one substrate.
In some cases, a plurality of power supplies for supplying different voltages to one chip are provided for the purpose of enabling transmission and reception of signals between different voltages.
In the case of such a chip, there are many cases in which a rise time of a voltage supplied by each power supply is restricted.
For example, as shown in FIG. 5, a case is considered in which the voltage V101 is supplied from the power supply 101 to the load 103 and the voltage V102 is supplied from the power supply 102 to the load 104.
Here, for example, the load 103 is a CPU, and the load 104 is a cache memory.
In this case, as shown in FIG. 6, first, the power supply 101 rises, and thereafter, when the voltage V101 reaches the voltage VA (for example, 5 V) at timing t1, the power supply 101 changes the trigger signal TRG from low level (L). Start up to high level (H).
The power supply 102 starts raising the voltage V102 at timing t2 based on the rising of the trigger signal TRG to high level, and the voltage V102 reaches the voltage VB (for example, 3.3 V) at timing t3.
As described above, when the load 103 is a CPU and the load 104 is a cache memory, the CPU accesses the cache memory after the voltage voltage V101 reaches the voltage VA and the CPU is started. It is necessary to accurately know the timing until the cache memory starts, that is, the timing when the power supply voltage V102 reaches the voltage VB.
[0003]
[Problems to be solved by the invention]
However, the rise time of the voltage supplied by the power supply depends on the load.
For example, in the examples illustrated in FIGS. 5 and 6, the time (t3−t2) from when the voltage V102 starts rising to when the voltage V102 reaches the voltage VB varies depending on the characteristics of the load 104.
Therefore, there is a problem that the time T from when the voltage V101 reaches the voltage VA to when the voltage V102 reaches the voltage VB cannot be accurately predicted.
[0004]
The present invention has been made in view of the above circumstances, and an object of the present invention is to supply a plurality of different supply voltages, and after one supply voltage reaches a desired voltage, the other supply voltage becomes a desired voltage. It is an object of the present invention to provide a power supply device and a power supply control method capable of controlling and predicting the time until the power supply reaches a high accuracy.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a power supply device of a first invention is a power supply device for supplying a first supply voltage and a second supply voltage, wherein the first supply voltage is reduced to a first voltage. Upon reaching the first power supply means for issuing a trigger, and supplying the second supply voltage at a third voltage lower than a second voltage until the first power supply means issues the trigger; And a second power supply means for raising the second supply voltage from the third voltage to the second voltage when the power supply means issues the trigger.
[0006]
In the power supply device according to the first invention, preferably, the second power supply means controls the second supply voltage so as to reduce a difference between the second supply voltage and a reference voltage, and Setting the reference voltage to the third voltage until the first power supply means issues the trigger, and setting the reference voltage to the second voltage when the first power supply means issues the trigger.
In the power supply device of the first invention, preferably, the first power supply means, upon receiving a power-on instruction, raises the first supply voltage to the first voltage, and the second power supply means Upon receiving a power-on instruction, the second supply voltage is increased to the third voltage.
[0007]
A power supply device according to a second aspect of the present invention is a power supply device that supplies a first supply voltage and a second supply voltage, and issues a first trigger when the first supply voltage reaches a first voltage. Until the second trigger occurs, the first supply voltage having a second voltage lower than the first voltage is supplied, and when the second trigger occurs, the first supply voltage is reduced to the second voltage. First power supply means for increasing the voltage from the first voltage to the first voltage, and the second trigger is issued when the second supply voltage reaches a fourth voltage lower than the third voltage, and the first trigger is provided. Supply the second supply voltage of the fourth voltage until the occurrence of the first trigger, and when the first trigger occurs, increase the second supply voltage from the fourth voltage to the third voltage Second power supply means.
[0008]
In the power supply device according to the second invention, preferably, the first power supply means controls the first supply voltage so as to reduce a difference between the first supply voltage and a first reference voltage, The first reference voltage is set to the second voltage until the second power source emits the second trigger, and when the second power source emits the second trigger, the first reference voltage is set to the first voltage. Is set to the first voltage, and the second power supply means controls the second supply voltage so as to reduce the difference between the second supply voltage and the second reference voltage. Setting the reference voltage to the fourth voltage until the first power supply unit issues the first trigger, and when the first power supply unit issues the first trigger, the reference voltage is set to the fourth voltage. Set to the third voltage.
In the power supply device according to the second invention, preferably, the first power supply means, upon receiving a power-on instruction, raises the first supply voltage to the first voltage, and the second power supply means Upon receiving a power-on instruction, the second supply voltage is increased to the fourth voltage.
[0009]
The power supply device according to the first and second inventions preferably has a plurality of the second power supply means for supplying the second supply voltages different from each other.
[0010]
A power control method according to a third aspect of the present invention is a power control method using a first power supply for supplying a first supply voltage and a second power supply for supplying a second supply voltage. A first power supply means for raising the first supply voltage toward a first voltage; and the first supply voltage raised in the first step is the first voltage. A second step of detecting whether the first power supply voltage has reached the first voltage, and a second step of detecting whether the first supply voltage has reached the first voltage in the second step. But a third step of supplying the second supply voltage of a third voltage lower than a second voltage, and the first supply voltage has reached the first voltage in the first step Is detected, the second power supply means raises the second supply voltage from the third voltage to the second voltage. And a fourth step.
[0011]
A power supply control method according to a fourth invention is a power supply control method using first power supply means for supplying a first supply voltage and second power supply means for supplying a second supply voltage. A first step in which one power supply means raises the first supply voltage to a second voltage lower than the first voltage, and wherein the second power supply means changes the second supply voltage to a third voltage. A second step of raising the voltage to a fourth voltage lower than a voltage, and a third step of detecting whether the second supply voltage raised in the second step has reached the fourth voltage. And a step until the third step detects that the second supply voltage has reached the fourth voltage, the first voltage means sets the first voltage of the second voltage to the first voltage. A fourth step of maintaining the supply voltage and detecting in the third step that the second supply voltage has reached the fourth voltage. Then, the fifth power supply means starts up the first supply voltage from the second voltage toward the first voltage, and the fifth power supply means starts up in the fifth step. A sixth step of detecting whether or not the first supply voltage has reached the first voltage; and a step of detecting that the first supply voltage has reached the first voltage in the sixth step. And a seventh step in which the second power supply means raises the second supply voltage from the fourth voltage to the third voltage when detected.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a power supply device according to an embodiment of the present invention will be described.
[First Embodiment]
This embodiment is an embodiment corresponding to the first invention and the third invention.
FIG. 1 is a configuration diagram of a power supply device 1 according to the first embodiment of the present invention, and FIG. 2 is a waveform diagram of a supply voltage V2, a trigger signal TRG1, and a supply voltage V3 of the power supply device 1 shown in FIG.
As shown in FIG. 1, the power supply device 1 includes, for example, a power supply unit 2, a power supply unit 3, and a main power supply unit 4.
Here, the power supply unit 2 corresponds to the first power supply unit of the present invention, and the power supply unit 3 corresponds to the second power supply unit of the present invention.
The power supply unit 2 supplies the load 5 with the supply voltage V2.
The load 5 is, for example, a CPU.
The power supply unit 3 supplies the load 6 with a supply voltage V3 different from the supply voltage V2.
The load 6 is, for example, a cache memory.
The main power supply unit 4 supplies a voltage V4 to the power supply unit 2 and the power supply unit 3.
[0013]
When the power supply device 1 receives the power-on instruction, the voltage control unit 11 raises the supply voltage V2 to a voltage VA1 (first voltage, for example, 5 V), and the voltage control unit 24 changes the supply voltage V3 to the reference voltage VB1. The voltage is raised to a reference voltage VB_STB (third voltage, for example, 2.8 V) lower than (second voltage, for example, 3.3 V).
Then, when the supply voltage V2 reaches the voltage VA1, a trigger signal TRG1 is generated, and the voltage control unit 24 raises the supply voltage V3 from the reference voltage VB_STB to the reference voltage VB1.
[0014]
Hereinafter, each component of the power supply device 1 shown in FIG. 1 will be described.
[Power supply unit 2]
The power supply unit 2 includes, for example, a voltage control unit 11 and a trigger generation unit 12.
For example, upon receiving a power-on instruction, the voltage control unit 11 changes the supply voltage V2 to be supplied to the load 5 from 0 to a voltage based on the voltage V4 from the original power supply unit 4 as shown in FIG. Start up at VA1.
The trigger generator 12 monitors the supply voltage V2 supplied to the load 5 by the voltage controller 11, and when the supply voltage V2 reaches the voltage VA1, as shown in FIG. 2B, sets the trigger signal TRG1 to low level ( It rises from L) to high level (H).
The trigger signal TRG1 may be either digital or analog.
The trigger generation unit 12 determines that the supply voltage V2 has reached the voltage VA1 at a timing when the load 5 is operated.
[0015]
[Power supply unit 3]
The power supply unit 3 includes, for example, a variable voltage unit 21, an output detection unit 22, a comparison unit 23, and a voltage control unit 24.
The variable voltage section 21 outputs the reference voltage VB_STB to the comparing section 23 when the trigger signal TRG1 from the trigger generating section 12 is at a low level, and outputs the reference voltage VB to the comparing section 23 when the trigger signal TRG1 is at a high level. Output to
Here, the reference voltage VB_STB is a voltage lower than the reference voltage VB1.
[0016]
The output detection unit 22 detects the supply voltage V3 supplied to the load 6 by the voltage control unit 24, and outputs this to the comparison unit 23.
[0017]
The comparing unit 23 compares the voltage V3 detected by the output detecting unit 22 with the reference voltage from the variable voltage unit 21 and outputs the difference voltage DIF to the voltage control unit 24.
[0018]
Upon receiving the power-on instruction, the voltage control unit 24 generates a supply voltage V3 to be supplied to the load 6 based on the voltage V4 (for example, 6 V) from the main power supply unit 4 so as to reduce the difference voltage DIF, This is supplied to the load 6.
[0019]
Hereinafter, an operation example of the power supply device 1 will be described with reference to FIG.
As an initial state, the trigger signal TRG1 is at a low level, and the variable voltage unit 21 outputs the reference voltage VB_STB to the comparison unit 23.
For example, when a power-on instruction is issued at a timing t11 shown in FIG. 2, the voltage control unit 11 raises the supply voltage V2 and the voltage control unit 24 supplies the supply voltage V2 as shown in FIGS. Start V3.
Then, for example, at timing t12, the supply voltage V3 supplied by the voltage control unit 24 reaches the reference voltage VB_STB, the difference voltage DIF becomes 0, and the supply voltage V3 is held at the reference voltage VB_STB.
[0020]
Thereafter, when the supply voltage V2 supplied by the voltage control unit 11 reaches the voltage VA1, as shown in FIG. 2B, the trigger generation unit 12 raises the trigger signal TRG1 from a low level to a high level.
The variable voltage unit 21 switches the reference voltage output to the comparison unit 23 from the reference voltage VB_STB to the reference voltage VB1 based on the rising of the trigger signal TRG1.
Then, as shown in FIG. 2C, the voltage control unit 24 raises the supply voltage V3 from the reference voltage VB_STB to the reference voltage VB1 based on the difference voltage DIF.
As a result, at timing t14, the supply voltage V3 reaches the reference voltage VB1.
[0021]
As described above, in the power supply device 1, when receiving the power-on instruction, the voltage controller 11 raises the supply voltage V2 to the voltage VA1, and the voltage controller 24 raises the supply voltage V3 to the reference voltage VB1 lower than the reference voltage VB1. Start up to VB_STB. Then, when the supply voltage V2 reaches the voltage VA1, a trigger signal TRG1 is generated, and the voltage control unit 24 raises the supply voltage V3 from the reference voltage VB_STB to the reference voltage VB1.
Therefore, compared to the case where the rising of the voltage V102 is started after the voltage V101 reaches the voltage VA as in the conventional power supply device shown in FIG. It is possible to predict and control the time T1 until 3 reaches the reference voltage VB1 with high accuracy. That is, the time affected by the load 6 is shorter than before, and the accuracy of prediction and control is improved accordingly.
Thereby, for example, when the load 5 is a CPU and the load 6 is a cache memory, the voltage V3 reaches the reference voltage VB1, the voltage V3 reaches the reference voltage VB1, and the cache memory It is possible to accurately specify the time until activation, and accurately specify the timing at which the CPU can access the cache memory.
[0022]
[Second embodiment]
This embodiment corresponds to the second invention and the fourth invention.
FIG. 3 is a configuration diagram of the power supply device 41 according to the first embodiment of the present invention, and FIG. 4 is a waveform diagram of the supply voltage V42, the trigger signal TRG1, the supply voltage V43, and the trigger signal TRG2 of the power supply device 41 shown in FIG. .
As illustrated in FIG. 3, the power supply device 41 includes, for example, a power supply unit 42, a power supply unit 43, and the main power supply unit 4.
Here, the power supply unit 42 corresponds to the first power supply unit of the present invention, and the power supply unit 43 corresponds to the second power supply unit of the present invention.
3, the components denoted by the same reference numerals as those in FIG. 1 are the same as those described in the first embodiment.
The power supply unit 42 supplies the supply voltage V42 to the load 5.
The power supply unit 43 supplies the load 6 with a supply voltage V43 different from the supply voltage V42.
The main power supply unit 4 supplies a voltage V4 to the power supply unit 42 and the power supply unit 43.
[0023]
When the power supply device 41 receives the power-on instruction, the voltage control unit 24 sets the supply voltage V43 to the reference voltage VB_STB (fourth voltage, for example, 2 V) lower than the reference voltage VB1 (third voltage, for example, 3.3 V). .8V).
When the supply voltage 43 reaches the reference voltage VB_STB, a trigger signal TRG2 is generated.
Further, in response to the power-on instruction, the voltage control unit 54 raises the supply voltage V42 to a reference voltage VA_STB (second voltage, for example, 4.5 V) lower than the reference voltage VA1 (first voltage, for example, 5 V).
Then, based on the trigger signal TRG2, the voltage control unit 54 raises the supply voltage V42 from the reference voltage VA_STB to the reference voltage VA1, and generates the trigger signal TRG1.
Then, the voltage control unit 24 raises the supply voltage V43 from the reference voltage VB_STB to the reference voltage VB1 based on the trigger signal TRG1.
[0024]
Hereinafter, each component of the power supply device 41 shown in FIG. 31 will be described.
[Power supply unit 42]
The power supply unit 42 includes, for example, a variable voltage unit 51, an output detection unit 52, a comparison unit 53, a voltage control unit 54, and the trigger generation unit 12.
The variable voltage section 51 outputs the reference voltage VA_STB to the comparing section 53 when the trigger signal TRG2 from the trigger generating section 45 is at a low level, and outputs the reference voltage VA1 to the comparing section 23 when the trigger signal TRG2 is at a high level. Output to
Here, the reference voltage VA_STB is a voltage lower than the reference voltage VA1.
[0025]
The output detection section 52 detects the supply voltage V42 supplied to the load 5 by the voltage control section 54 and outputs this to the comparison section 53.
[0026]
The comparison unit 53 compares the voltage V42 detected by the output detection unit 52 with the reference voltage from the variable voltage unit 51, and outputs the difference voltage DIF1 to the voltage control unit 54.
[0027]
Upon receiving the power-on instruction, the voltage control unit 54 raises the supply voltage V42 as shown in FIG. 4A, and sets the load based on the voltage V4 from the original power supply unit 4 so as to reduce the difference voltage DIF1. A supply voltage V42 to be supplied to the load 5 is generated and supplied to the load 5.
[0028]
The trigger generator 12 monitors the supply voltage V42 supplied to the load 5 by the voltage controller 54, and when the supply voltage V42 reaches the reference voltage VA1, as shown in FIG. 4B, sets the trigger signal TRG1 to low level. It rises from (L) to high level (H).
[0029]
[Power supply unit 43]
The power supply unit 43 includes, for example, a variable voltage unit 21, an output detection unit 22, a comparison unit 23, a voltage control unit 24, and a trigger generation unit 45.
The variable voltage section 21 outputs the reference voltage VB_STB to the comparing section 23 when the trigger signal TRG1 from the trigger generating section 12 is at a low level, and outputs the reference voltage VB1 to the comparing section 23 when the trigger signal TRG is at a high level. Output to
Here, the reference voltage VB_STB is a voltage lower than the reference voltage VB1.
[0030]
The output detection unit 22 detects the supply voltage V43 supplied to the load 6 by the voltage control unit 24 and outputs this to the comparison unit 23.
[0031]
The comparing unit 23 compares the voltage V43 detected by the output detecting unit 22 with the reference voltage from the variable voltage unit 21 and outputs the difference voltage DIF2 to the voltage control unit 24.
[0032]
Upon receiving the power-on instruction, the voltage control unit 24 raises the supply voltage V43 and generates the supply voltage V43 to be supplied to the load 6 based on the voltage V4 from the original power supply unit 4 so as to reduce the difference voltage DIF2. Then, this is supplied to the load 6.
[0033]
Hereinafter, an operation example of the power supply device 41 will be described with reference to FIG.
As an initial state, the trigger signals TRG1 and TRG2 are at a low level, the variable voltage unit 21 outputs the reference voltage VB_STB to the comparison unit 23, and the variable voltage unit 51 outputs the reference voltage VA_STB to the comparison unit 53. .
For example, when a power-on instruction is generated at timing t21 shown in FIG. 4, as shown in FIGS. 2A and 2C, the voltage control unit 54 raises the supply voltage V42 and the voltage control unit 24 Start V43.
Then, for example, at timing t22, the supply voltage V43 supplied by the voltage control unit 24 reaches the reference voltage VB_STB, the difference voltage DIF2 becomes 0, and the supply voltage V43 is held at the reference voltage VB_STB.
At this time, as shown in FIG. 4D, the trigger generation section 45 raises the trigger signal TRG2 from a low level to a high level.
[0034]
Then, the variable voltage unit 51 switches the reference voltage output to the comparison unit 53 from the reference voltage VA_STB to the reference voltage VA1 based on the rising of the trigger signal TRG2.
Then, as shown in FIG. 4A, the voltage controller 54 raises the supply voltage V42 from the reference voltage VA_STB to the reference voltage VA1 based on the difference voltage DIF1. As a result, at timing t23, the supply voltage V42 reaches the reference voltage VA1.
[0035]
When the supply voltage V42 reaches the reference voltage VA1, the trigger generator 12 raises the trigger signal TRG1 from a low level to a high level.
[0036]
Then, the variable voltage unit 21 switches the reference voltage output to the comparison unit 23 from the reference voltage VB_STB to the reference voltage VB1 based on the rising of the trigger signal TRG1.
Then, as shown in FIG. 4C, the voltage control unit 24 raises the supply voltage V43 from the reference voltage VB_STB to the reference voltage VB1 based on the difference voltage DIF2. Thus, at timing t24, the supply voltage V43 reaches the reference voltage VB1.
[0037]
As described above, in the power supply device 41, when receiving the power-on instruction, the voltage control unit 54 raises the supply voltage V42 to the reference voltage VA_STB lower than the reference voltage VA1, and the voltage control unit 24 sets the supply voltage V43 to the reference voltage VA_STB. The voltage rises to a reference voltage VB_STB lower than the voltage VB1.
Then, after the supply voltage V43 reaches the reference voltage VB_STB, the voltage control unit 54 raises the supply voltage V42 from the reference voltage VA_STB to the reference voltage VA1.
Therefore, according to the power supply device 41, it is possible to prevent the supply voltage V42 from reaching the reference voltage VA1 before the supply voltage V43 reaches the reference voltage VB_STB, which is smaller than the power supply device 1 according to the first embodiment described above. The time T3 from when the supply voltage V42 reaches the reference voltage VA1 to when the supply voltage V43 reaches the reference voltage VB1 can be more stably and accurately predicted and controlled.
[0038]
In the power supply devices 1 and 41 of the above-described embodiment, even when the supply voltage changes due to the device change, it can be handled by changing the reference voltage.
The present invention is not limited to the embodiments described above.
For example, the supply voltage of the power supply unit 3, the power supply unit 42, and the power supply unit 43 can be changed by changing the value of the trigger signal to an analog signal in accordance with the device change.
Further, the present invention can be applied as a measure against overshoot of the power supply when the load 5 or the load 6 is an inductive load.
In the case of an inductive load, if the supply voltage is rapidly increased, a problem such as overshoot occurs. However, in the power supply devices 1 and 42, such a problem can be solved by gradually increasing the reference voltage of the variable voltage unit. .
[0039]
【The invention's effect】
According to the present invention, when supplying a plurality of different supply voltages, the time from when one supply voltage reaches a desired voltage to when the other supply voltage reaches a desired voltage is accurately controlled and predicted. A power supply device and a power supply control method that can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power supply device according to a first embodiment of the present invention.
FIG. 2 is a waveform diagram of a supply voltage V2, a trigger signal TRG1, and a supply voltage V3 of the power supply device shown in FIG.
FIG. 3 is a configuration diagram of a power supply device according to a second embodiment of the present invention.
FIG. 4 is a waveform diagram of a supply voltage V42, a trigger signal TRG1, a supply voltage V43, and a trigger signal TRG2 of the power supply device shown in FIG.
FIG. 5 is a diagram for explaining a conventional power supply device.
FIG. 6 is a diagram for explaining a conventional power supply device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Power supply device, 2 ... Power supply part, 3 ... Power supply part, 4 ... Original power supply part, 11 ... Voltage control part, 12 ... Trigger generation part, 21 ... Variable voltage part, 22 ... Output detection part, 23 ... Comparison part, Reference numeral 24: voltage control unit, 42: power supply unit, 43: power supply unit, 45: trigger generation unit, 51: variable voltage unit, 52: output detection unit, 53: comparison unit, 54: voltage control unit

Claims (9)

A power supply for supplying a first supply voltage and a second supply voltage,
First power supply means for generating a trigger when the first supply voltage reaches the first voltage;
The first power supply means supplies the second supply voltage having a third voltage lower than the second voltage until the first power supply means emits the trigger, and when the first power supply means emits the trigger, the second power supply means supplies the second supply voltage. Power supply means for increasing a supply voltage from the third voltage to the second voltage. The second power supply means controls the second supply voltage so as to reduce a difference between the second supply voltage and a reference voltage, and controls the reference voltage until the first power supply means issues the trigger. 2. The power supply device according to claim 1, wherein the reference voltage is set to the third voltage, and the reference voltage is set to the second voltage when the first power supply unit issues the trigger. Upon receiving a power-on instruction, the first power supply unit increases the first supply voltage to the first voltage,
3. The power supply device according to claim 1, wherein the second power supply unit increases the second supply voltage to the third voltage when receiving a power-on instruction. 4. A power supply for supplying a first supply voltage and a second supply voltage,
A first trigger is issued when the first supply voltage reaches the first voltage, and the first supply voltage of a second voltage lower than the first voltage is supplied until a second trigger occurs. And when the second trigger occurs, first power supply means for increasing the first supply voltage from the second voltage to the first voltage;
The second trigger is issued when the second supply voltage reaches a fourth voltage lower than the third voltage, and the second supply voltage of the fourth voltage is generated until the first trigger occurs. And a second power supply means for increasing the second supply voltage from the fourth voltage to the third voltage when the first trigger occurs. The first power supply controls the first supply voltage so as to reduce a difference between the first supply voltage and a first reference voltage, and the second power supply controls the second trigger. The first reference voltage is set to the second voltage until the second trigger is issued, and when the second power supply means issues the second trigger, the first reference voltage is set to the first voltage. ,
The second power supply controls the second supply voltage so as to reduce a difference between the second supply voltage and a second reference voltage, and the first power supply controls the first trigger. 5. The method according to claim 4, wherein the reference voltage is set to the fourth voltage until the first voltage is issued, and when the first power supply unit issues the first trigger, the reference voltage is set to the third voltage. Power supply. Upon receiving a power-on instruction, the first power supply unit increases the first supply voltage to the first voltage,
The power supply device according to claim 4, wherein the second power supply unit increases the second supply voltage to the fourth voltage when receiving a power-on instruction. The power supply device according to any one of claims 1 to 6, further comprising a plurality of the second power supply units that supply the different second supply voltages. A power supply control method using first power supply means for supplying a first supply voltage and second power supply means for supplying a second supply voltage,
A first step in which the first power supply means raises the first supply voltage toward a first voltage;
A second step of detecting whether or not the first supply voltage started in the first step has reached the first voltage;
Until it is detected in the second step that the first supply voltage has reached the first voltage, the second power supply means operates the third power supply of the third voltage lower than the second voltage. A third step of providing a second supply voltage;
When it is detected in the first step that the first supply voltage has reached the first voltage, the second power supply means changes the second supply voltage from the third voltage. A fourth step of raising the voltage to the second voltage. A power supply control method using first power supply means for supplying a first supply voltage and second power supply means for supplying a second supply voltage,
A first step in which the first power supply means raises the first supply voltage to a second voltage lower than the first voltage;
A second step in which the second power supply means raises the second supply voltage to a fourth voltage lower than a third voltage;
A third step of detecting whether or not the second supply voltage started in the second step has reached the fourth voltage;
Until it is detected in the third step that the second supply voltage has reached the fourth voltage, the first voltage means changes the first supply voltage of the second voltage. A fourth step of holding;
When it is detected in the third step that the second supply voltage has reached the fourth voltage, the first power supply means changes the first supply voltage from the second voltage. A fifth step of raising the voltage toward the first voltage;
A sixth step of detecting whether or not the first supply voltage started in the fifth step has reached the first voltage;
When it is detected in the sixth step that the first supply voltage has reached the first voltage, the second power supply means changes the second supply voltage from the fourth voltage to the fourth voltage. A power supply control method including: a seventh step of starting up to a third voltage.

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