JP2002300769A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device which reduces current consumption under a light load and improves its conversion efficiency of electric power as a whole. SOLUTION: When heavy-loaded, a DC/DC converter 1 is operated. The DC/DC converter has a high conversion efficiency of electric power although the self-current consumption is large. Therefore, when heavy-loaded, use of the DC/DC converter having high conversion efficiency is effective since the load current is increased, and the self-current consumption can be ignored. On the other hand, when light-loaded, a serial regulator 2 is operated. The serial regulator 2 of which the self-current consumption is small has a low conversion efficiency of electric power. Therefore, when light-loaded, even if the serial regulator 2 is used, the low efficiency of the power conversion can be ignored since the self-current consumption is small. Accordingly, when light-loaded the self-current consumption can be reduced, and the conversion efficiency of electric power is as a whole improved when it is used under both light load and heavy load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device in which power consumption is reduced by reducing its own current consumption at a light load, thereby improving power conversion efficiency as a whole.

[0002]

2. Description of the Related Art Heretofore, as a power supply device, for example, a charge pump type DC / DC converter and a switching regulator have been known. The charge pump type DC / DC converter converts an input voltage into a predetermined output voltage by using charging and discharging of a capacitor.

A switching regulator switches an input voltage and converts the input voltage to a predetermined output voltage.

[0004]

However, since the charge pump type DC / DC converter is designed and operated under the assumption of the maximum load, even if the state of the load or the like fluctuates, the charge pump type DC / DC converter is operated by itself. The current consumption was the same. For this reason, there is no power waste at heavy load, but there is a problem that power becomes excessive at light load, power is wasted, and power conversion efficiency is reduced as a whole.

On the other hand, the switching regulator consumes a large amount of current but has a high power conversion efficiency. Therefore, the high power conversion efficiency is effective when the load is heavy, but the current consumption is large when the load is light. However, there is a problem that the power conversion efficiency is reduced as a whole. Therefore,
It is an object of the present invention to provide a power supply device capable of reducing its own current consumption under a light load and improving the power conversion efficiency as a whole in view of the above points.

[0006]

Means for Solving the Problems In order to solve the above problems and achieve the object of the present invention, the respective inventions according to claims 1 to 18 are configured as follows. In other words, the invention according to claim 1 is a charge pump type DC / DC converter that converts an input voltage to a predetermined output voltage by using charging and discharging of a capacitor, and that receives the input voltage and outputs its own output. A series regulator for continuously controlling the output voltage so that the voltage becomes a predetermined voltage, wherein the DC / DC converter and the series regulator are selectively operated in accordance with the magnitude of a load to operate the DC / DC converter. In which the output voltage is extracted.

According to a second aspect of the present invention, in the power supply device according to the first aspect, the DC / DC converter and the series regulator are selectively operated in accordance with the magnitude of the load to operate the DC / DC converter and the series regulator. And a control input terminal for inputting a signal for extracting the output voltage from the outside.

According to a third aspect of the present invention, in the power supply device according to the first or second aspect, the DC / DC converter is operated when the load is large, and the DC / DC converter is operated when the load is small. It is characterized by operating a series regulator. Thus, in each of the first to third aspects of the present invention, the charge pump type DC / DC converter and the series regulator having different properties are combined, and the DC / DC converter and the series regulator are changed according to the magnitude of the load. The operation is selectively performed to extract the output voltage on the operation side.

Specifically, when the load is heavy, D
The C / DC converter was operated. DC / D
Although the C converter consumes a large amount of current, it has high conversion efficiency of output power with respect to input power. For this reason, when the load is heavy, the load current increases. Therefore, it is effective to use a DC / DC converter with high power conversion efficiency, and the current consumption of the DC / DC converter can be ignored because the load current is large.

On the other hand, when the load is light, the series regulator is operated. The series regulator has low power consumption efficiency, although its current consumption is small. Therefore, at light load, even if a series regulator is used, its current consumption is small.
The low efficiency of the power conversion can be ignored. Accordingly, current consumption can be reduced under a light load compared to a heavy load, so that the power conversion efficiency can be improved as a whole when used under both heavy and light loads.

According to a fourth aspect of the present invention, there is provided a switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage, wherein the input voltage is input and its own output voltage becomes a predetermined voltage. A series regulator for continuously controlling the output voltage as described above, and the switching regulator and the series regulator are selectively operated according to the magnitude of the load to take out the output voltage on the operation side. It is characterized by having.

According to a fifth aspect of the present invention, in the power supply device according to the fourth aspect, the switching regulator and the series regulator are selectively operated in accordance with the magnitude of the load so that the output voltage on the operation side is controlled. And a control input terminal therefor.

According to a sixth aspect of the present invention, in the power supply device according to the fourth or fifth aspect, the switching regulator is operated when the load is large, and the series regulator is operated when the load is small. Is operated. As described above, in each of the inventions according to claims 4 to 6, the switching regulator and the series regulator having different properties are combined, and the switching regulator and the series regulator are selectively operated according to the magnitude of the load. The output voltage on the operating side is taken out.

Specifically, when the load is heavy, the switching regulator is operated. The switching regulator consumes a large amount of current, but has high conversion efficiency of output power to input power. For this reason, when the load is heavy, the load current increases. Therefore, it is effective to use a switching regulator having high power conversion efficiency, and the current consumption of the switching regulator can be ignored because the load current is large.

On the other hand, when the load is light, the series regulator is operated. The series regulator has low power consumption efficiency, although its current consumption is small. Therefore, at light load, even if a series regulator is used, its current consumption is small.
The low efficiency of the power conversion can be ignored. Accordingly, current consumption can be reduced under a light load compared to a heavy load, so that the power conversion efficiency can be improved as a whole when used under both heavy and light loads.

According to a seventh aspect of the present invention, there is provided a charge pump type DC / DC converter for converting an input voltage into a predetermined output voltage by utilizing charging and discharging of a capacitor, and a self-input DC / DC converter. A series regulator for continuously controlling the output voltage so that the output voltage becomes a predetermined voltage, wherein the DC / DC converter and the series regulator are generated in advance based on a predicted or expected load change. The operation is selectively performed according to an operation command signal, and an output voltage on the operation side is taken out.

According to an eighth aspect of the present invention, in the power supply device according to the seventh aspect, the selective operation of the DC / DC converter and the series regulator includes determining the magnitude of a load in addition to the operation command signal. The detection is performed using a load detection signal obtained by the detection. According to a ninth aspect of the present invention, in the power supply device according to the seventh or eighth aspect, the DC / DC converter is operated when the load is large, and the series regulator is operated when the load is small. It is characterized by being operated.

As described above, according to each of the seventh to ninth aspects, the same operation and effect as those of the first to third aspects can be realized. Claims 7 to 9
In each of the inventions described above, the DC / DC converter and the series regulator are selectively operated in accordance with an operation command signal generated in advance based on a predicted or expected change in load, and an output voltage on the operation side is taken out. I did it. For this reason, the DC / DC converter and the series regulator can be appropriately selected and operated according to the change in the load.

Further, in the invention according to claims 8 and 9, the selective operation of the DC / DC converter and the series regulator is detected by detecting the magnitude of the load in addition to the operation command signal. It was done using signals. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation command signal is used.

According to a tenth aspect of the present invention, there is provided a switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage, wherein the input voltage is input and its own output voltage becomes a predetermined voltage. A series regulator for continuously controlling the output voltage of the switching regulator and the series regulator selectively according to an operation command signal generated in advance based on a predicted or expected load change. The operation is performed, and the output voltage on the operation side is taken out.

According to an eleventh aspect of the present invention, in the power supply device according to the tenth aspect, the selective operation of the switching regulator and the series regulator detects a magnitude of a load in addition to the operation command signal. This is characterized by using a load detection signal obtained as a result. According to a twelfth aspect of the present invention, in the power supply device according to the tenth or eleventh aspect, the switching regulator is operated when the load is large, and the series regulator is operated when the load is small. It is characterized by the following.

As described above, according to each of the tenth to twelfth aspects, the same operations and effects as those of the fourth to sixth aspects can be realized. In each of the inventions according to claims 10 to 12, the switching regulator and the series regulator are selectively operated in accordance with an operation command signal generated in advance based on a predicted or planned change in load, and The output voltage on the operating side is taken out. For this reason, the switching regulator and the series regulator can be appropriately selected and operated according to the change in the load.

Further, in the invention according to the eleventh and twelfth aspects, the selective operation of the switching regulator and the series regulator can be performed by not only the operation command signal but also the load detection signal obtained by detecting the magnitude of the load. I used to do it. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation command signal is used.

According to a thirteenth aspect of the present invention, there is provided a charge pump type DC / DC converter for converting an input voltage to a predetermined output voltage by utilizing charging and discharging of a capacitor, and a self-input DC / DC converter. A series regulator for continuously controlling the output voltage so that the output voltage becomes a predetermined voltage. The series regulator is always operated, and the DC / DC converter is operated according to the magnitude of a load. It is characterized by having.

Thus, in the invention according to the thirteenth aspect, a DC / DC converter having different characteristics and a series regulator are combined, for example, a series regulator having a small capacity is always operated, and a DC / DC converter having a large capacity is always operated.
The DC converter is operated according to the magnitude of the load. Therefore, according to the invention of claim 13, current consumption can be reduced at light load, and power conversion efficiency can be improved as a whole.

According to a fourteenth aspect of the present invention, a switching regulator that switches an input voltage and converts the input voltage to a predetermined output voltage, and that the input voltage is input and its own output voltage becomes a predetermined voltage And a series regulator for continuously controlling the output voltage of the switching regulator so as to always operate the series regulator and to operate the switching regulator according to the magnitude of the load. is there.

Thus, in the invention according to claim 14, a switching regulator and a series regulator having different properties are combined, for example, a series regulator with a small capacity is always operated, and a switching regulator with a large capacity is changed according to the size of the load. I made it work. Therefore, according to the invention of claim 14, current consumption can be reduced at a light load, and the power conversion efficiency can be improved as a whole.

According to a fifteenth aspect of the present invention, there is provided a charge pump type DC / DC converter for converting an input voltage to a predetermined output voltage by utilizing charging and discharging of a capacitor, and a self-input DC / DC converter. A series regulator for continuously controlling the output voltage so that the output voltage becomes a predetermined voltage, wherein the series regulator is always operated, and the control of the operation of the DC / DC converter is predicted or scheduled. Is performed in accordance with an operation control signal generated in advance on the basis of the change.

According to a sixteenth aspect of the present invention, in the power supply device according to the fifteenth aspect, the operation of the DC / DC converter is controlled by detecting a magnitude of a load in addition to the operation control signal. This is characterized by using a load detection signal to be performed. Thus, in the invention according to claim 15 and claim 16,
An operation control that combines a DC / DC converter with a different characteristic and a series regulator to always operate the series regulator, and controls the operation of the DC / DC converter in advance based on a predicted or expected load change. It was performed according to the signal. For this reason, current consumption can be reduced at light load, power conversion efficiency can be improved as a whole, and the DC / DC converter can be appropriately operated according to a change in load.

In the invention according to claim 16, the DC /
Control of the operation of the DC converter, in addition to the operation control signal,
The detection is performed using a load detection signal obtained by detecting the magnitude of the load. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation control signal is used. The invention according to claim 17 is a switching regulator that switches an input voltage and converts the input voltage to a predetermined output voltage, and receives the input voltage and controls the input voltage so that its own output voltage becomes a predetermined voltage. A series regulator for continuously controlling the output voltage, wherein the series regulator is always operated, and the control of the operation of the switching regulator is controlled in advance based on a predicted or scheduled load change. It is characterized by performing according to a signal.

According to an eighteenth aspect of the present invention, in the power supply device according to the seventeenth aspect, the operation of the switching regulator is controlled by detecting a magnitude of the load in addition to the operation control signal. This is characterized in that the detection is performed using a detection signal.
As described above, in the inventions according to the seventeenth and eighteenth aspects, a switching regulator having different properties and a series regulator are combined to always operate the series regulator, and control of the operation of the switching regulator is controlled by a predicted or scheduled load. Is performed in accordance with an operation control signal generated in advance based on a change in. Therefore, current consumption can be reduced at light load,
In addition to improving the power conversion efficiency as a whole, the switching regulator can be appropriately operated according to a change in load.

In the invention according to claim 18, control of the operation of the switching regulator is performed using a load detection signal obtained by detecting the magnitude of the load, in addition to the operation control signal. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation control signal is used.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a power supply according to the present invention will be described with reference to FIG. As shown in FIG. 1, the first embodiment of the power supply device includes a charge-pump type step-down DC / DC converter 1 having different properties and a series regulator 2, and based on a light load determination signal S1. , Selectively operate the step-down DC / DC converter 1 and the series regulator 2,
The output voltage on the operation side is taken out from the output terminal 7.

The step-down DC / DC converter 1 converts an input voltage Vin input to the input terminal 4 into a predetermined output voltage Vout by using charging and discharging of a capacitor. And a drive circuit 12 for driving the step-down charge pump circuit 11. The step-down charge pump circuit 11 includes, for example, a switching MOS transistor Q as shown in FIG.
A first charge pump circuit 11A comprising a capacitor C1 and a switching MOS transistor Q
A second charge pump circuit 12A including a charge pump circuit 11A and a capacitor C2;
And a second charge pump circuit 12A. The switch MOS transistor Q5 is connectable to the second charge pump circuit 12A and the output capacitor C3.

More specifically, the MOS transistor Q
1 has its source connected to the input terminal 4 and its drain connected to the source of the MOS transistor Q3 via the capacitor C1. The drain of the MOS transistor Q3 is connected to the output terminal 7. Also, MOS
The transistor Q2 has a source connected to the drain of the MOS transistor Q1, and a drain connected to the output terminal 7.
It is connected to the. Further, the MOS transistor Q4
Has its drain connected to the source of the MOS transistor Q3 and the source of the MOS transistor Q5, and its source is grounded. A capacitor C3 is connected between the output terminal 7 and the ground.

The MOS transistor Q11 has a source connected to the input terminal 4 and a drain connected to the capacitor C
2 and to the source of the MOS transistor Q13 and to the drain of the MOS transistor Q5. The drain of the MOS transistor Q13 is connected to the output terminal 7. The source of the MOS transistor Q12 is the MOS transistor Q1.
1 is connected to the output terminal 7. Further, the MOS transistor Q14
Has its drain connected to the source of MOS transistor Q13 and its source grounded.

MOS transistors Q1-Q5, Q11-
A predetermined drive signal is input to each of the gates 14 from the drive circuit 12 shown in FIG. 1, and the MOS transistors Q1 to Q5 and Q11 to 14 are controlled to be turned on and off by the respective drive signals. The drive circuit 12 controls each MO of the step-down charge pump circuit 11 according to the mode set by the setting mode signal S2 input from the setting mode terminal 5.
A drive signal for driving the S transistors Q1 to Q5 and Q11 to Q14 is generated based on an oscillation signal of an oscillation circuit (not shown).

Here, the setting mode which can be set by the setting mode signal S1 is to drive the step-down type charge pump circuit 11 complementarily or non-complementarily, and to set the step-down ratio of the input voltage (for example, 1/1 times, 1/2 times). , 2/3 times etc.)
It is. The drive circuit 12 stops its operation or inhibits its output based on an inverted signal S3 obtained by inverting the light load determination signal S2 input from the control input terminal 6 by the inverter 3.

The series regulator 2 has an input voltage Vi
n is input, and the output voltage Vout is continuously controlled so that its own output voltage Vout becomes a predetermined voltage. For example, the output voltage Vout has a configuration as shown in FIG. That is, in the series regulator 2, the MOS transistor Q21 is connected between the input terminal 4 and the output terminal 7, and the resistor R is connected between the output terminal 7 and the ground.
1, a resistor R2 and a switch SW1 are connected in series. The error amplifier 21 outputs the output voltage Vout to a resistor R
1. The divided voltage divided by R2 is compared with a reference voltage, an output voltage corresponding to the comparison is applied to the gate of the MOS transistor Q21, and the on-resistance of the MOS transistor Q21 is controlled. A voltage can be obtained.

The output voltage of the error amplifier 21 is controlled to be on / off by a light load determination signal S1 input to the control input terminal 6. Also, the switch SW1
The opening / closing of the switch is controlled by the light load determination signal S1. Next, the operation of the first embodiment having such a configuration will be described with reference to the drawings.

When the load of the first embodiment is a heavy load, the light load determination signal S1 becomes, for example, "L" level.
Therefore, the light load determination signal S1 is directly input to the error amplifying circuit 21 and the switch SW1 of the series regulator 2, and is inverted to “H” level by the inverter 3 to drive the step-down DC / DC converter 1. 12 is input.

As a result, the step-down DC / DC converter 1
On the side, the drive circuit 12 is in an operation state or a state in which a drive signal can be output. Accordingly, predetermined driving signals corresponding to the mode set by the setting mode signal S2 are output from the driving circuit 12 to the MOS transistors Q1 to Q5, Q1.
1 to Q14 are input to corresponding gates. For this reason,
The step-down charge pump circuit 11 operates according to the set mode, generates a predetermined output voltage Vout, and outputs this to the output terminal 7.

On the other hand, on the series regulator 2 side, the output of the error amplifier 21 is inhibited and the switch S
Since W1 is open, the series regulator 2
Does not operate and no output voltage is generated. Next, when the load of the first embodiment is a light load, the light load determination signal S1 becomes, for example, “H” level. Therefore, the light load determination signal S
1 is the error amplifier 2 of the series regulator 2
1 and the switch SW1, respectively, and is inverted by the inverter 3 to the “L” level so that the step-down DC / D
It is input to the drive circuit 12 of the C converter 1.

As a result, the step-down DC / DC converter 1
On the side, the drive circuit 12 is in a stopped state or a state in which the output of the drive signal is prohibited. Therefore, the driving circuit 12
, No drive signal is output, so that the step-down charge pump circuit 11 stops operating and no output voltage is generated. On the other hand, on the series regulator 2 side, the output voltage of the error amplifier 21 is output and the switch SW1 is closed, so that the series regulator 2 is in the operating state and the output voltage is output to the output terminal 7. Is done.

Next, the step-down charge pump circuit 11
An example of the case of operating according to the mode set by the setting mode signal S2 will be described with reference to FIGS.
First, a case where complementary operation is performed and a mode in which the step-down voltage is 1/1 times is set will be described with reference to FIG.
In this case, the first and second charge pump circuits 11
A and 11B are in the state shown in FIG. 4A in the first period, and are in the state shown in FIG. 4B in the second period. The operation of the period is alternately repeated.

That is, in the first period, only the MOS transistors Q2 and Q4 are turned on by the drive circuit 12 in the first charge pump circuit 11A, and the charge voltage of the capacitor C1 in the previous second period becomes equal to the output voltage Vout. (See FIG. 4A). In the same first period, the second
The charge pump circuit 11 </ b> B
Only the S transistors Q11 and Q14 are turned on, and the capacitor C2 is charged by the input voltage Vin (FIG. 4).
(A)).

On the other hand, in the second period, only the MOS transistors Q1 and Q4 of the first charge pump circuit 11A are turned on by the drive circuit 12, and the input voltage Vi
The capacitor C2 is charged by n (see FIG. 4B). In the same second period, in the second charge pump circuit 11B, only the MOS transistors Q12 and Q14 are turned on by the drive circuit 12, and the charging voltage of the capacitor C2 in the first period becomes the output voltage Vout (FIG. 4).
(B)).

Next, in the complementary operation, the step-down voltage becomes 1 /
The case where the double mode is set will be described with reference to FIG. In this case, the first and second charge pump circuits 11A and 11B are in a state as shown in FIG. 5A during the first period, and as shown in FIG. 5B during the second period. The operation in the first period and the operation in the second period are alternately repeated. Here, the detailed description is omitted.

As described above, in the first embodiment, when the load is heavy, the charge pump type step-down DC
The / DC converter 1 is operated. Step-down DC
/ DC converter 1 has a current consumption of, for example, 100
Although it is as large as μA, the conversion efficiency of the output power with respect to the input power (power conversion efficiency) is as high as 90%, for example. For this reason, when the load is heavy, the load current increases. Therefore, it is effective to use the step-down DC / DC converter 1 having a high power conversion efficiency. it can.

On the other hand, when the load is light, the series regulator 2 is operated. The series regulator 2 has a small current consumption of, for example, 1 μA, but has a low power conversion efficiency of, for example, 60%. Therefore, when the load is light, even if the series regulator 2 is used, the low power conversion efficiency can be ignored because the current consumption of the series regulator 2 is small.

Therefore, according to the first embodiment, current consumption can be reduced at a light load compared to a heavy load, so that the power consumption as a whole can be reduced when both heavy loads and light loads are used. Conversion efficiency can be improved. For this reason, particularly when using battery-operated electronic devices,
When operating in the standby state, useless consumption of the battery can be prevented, and the battery can be used for a long time.

In the first embodiment, the step-down DC / DC converter 1 and the series regulator 2 are selectively operated to extract the output voltage on the operation side. Therefore, it is necessary to prevent a period during which no output voltage is generated from occurring. First, step-down DC
/ DC converter 1 operation to series regulator 2
The case where the operation is switched to the operation described above will be described.

At this time, since the light load determination signal S1 changes from "L" level to "H" level, this immediately causes the error amplifier 2 on the series regulator 2 side.
1 and the switch SW1 is closed. As a result, the series regulator 2 immediately starts operating. On the other hand, the change of the light load determination signal S1 is detected by appropriate means, and when this change is detected, a timer (not shown) is started and a predetermined time is counted.
After the counting is completed, an end signal is generated. In response to the end signal, the drive circuit 12 of the step-down DC / DC converter 1 is set to a state where the operation is stopped or a state where the output of the drive signal is prohibited. As a result, the step-down DC / DC converter 1 stops its operation after the operation of the series regulator 2 becomes stable.

With such an operation, the step-down DC / DC
When switching from the operation of the converter 1 to the operation of the series regulator 2, it is possible to prevent a period during which no output voltage is generated from occurring. Next, conversely, series regulator 2
The case where the operation is switched from the above operation to the operation state of the step-down DC / DC converter 1 will be described.

At this time, the light load determination signal S1 changes from "H" level to "L" level, and this is converted by the inverter 3 and input to the drive circuit 12 of the step-down DC / DC converter 1. . Therefore, the drive circuit 12 immediately transitions to an operating state or a state in which a drive signal can be output, and the step-down DC / DC converter 1 immediately starts operating.

On the other hand, the change of the light load determination signal S1 is detected by an appropriate means, and when this change is detected, a timer is started and a predetermined time is counted, and an end signal is generated after the counting is completed. By this end signal, the output voltage of the error amplifier 21 on the series regulator 2 side is not output, and the switch SW1 is opened. As a result, the series regulator 2 operates after the step-down DC / DC converter 1 becomes stable.
The operation stops.

By such an operation, when switching from the operation of the series regulator 2 to the operation of the step-down DC / DC converter 1, it is possible to prevent a period during which no output voltage is generated from occurring. Next, a second embodiment of the power supply device of the present invention will be described with reference to FIG.

As shown in FIG. 6, the second embodiment of the power supply device includes a step-down switching regulator 8 and a series regulator 2 having different properties, respectively.
The step-down switching regulator 8 and the series regulator 2 are selectively operated based on the light load determination signal S 1, and the output voltage on the operation side is extracted from the output terminal 3.

The series regulator 2 is the same as the series regulator 2 shown in FIGS.
The step-down switching regulator 8 switches an input voltage and converts the input voltage to a predetermined output voltage, and has, for example, a configuration as shown in FIG.

That is, in the step-down switching regulator 8, the MOS transistor Q31 and the coil L1 are connected in series between the input terminal 4 and the output terminal 7. One end of the coil L1 is grounded via a diode D1, and the other end of the coil L1 is grounded via a capacitor C4. The control circuit 31 generates a switching signal whose pulse frequency or pulse width changes according to the magnitude of the output voltage Vout.
The on / off control of the S transistor Q31 is performed so that a desired output voltage can be obtained.

The control circuit 31 stops its operation or inhibits its output based on an inverted signal S3 obtained by inverting the light load determination signal S1 inputted from the control input terminal 6 by the inverter 3. I have. Next, an operation in the second embodiment having such a configuration will be described with reference to the drawings.

When the load of the second embodiment is a heavy load, the light load determination signal S1 becomes, for example, "L" level.
Therefore, the light load determination signal S2 is directly input to the error amplifier 21 and the switch SW1 of the series regulator 2, and is inverted to “H” level by the inverter 3, and the inverted signal S3 is output to the step-down switching regulator 8 Is input to the control circuit 31.

As a result, on the side of the step-down switching regulator 8, the control circuit 31 is in an operating state or a state in which the output thereof is possible. Therefore, the step-down switching regulator 8 is in an operating state, and a desired output voltage is obtained. On the other hand, on the series regulator 2 side, the output voltage of the error amplifier 21 is not output and the switch SW
Since 1 is open, the series regulator 2 does not generate an output voltage.

Next, when the load of the first embodiment is a light load, the light load determination signal S1 becomes, for example, "H" level. Therefore, the light load determination signal S1 is directly input to the error amplifier 21 and the switch SW1 of the series regulator 2, and is inverted to the "L" level by the inverter 3, and the inverted signal S3 of the step-down switching regulator 8 is output. It is input to the control circuit 31. As a result, on the side of the step-down switching regulator 8, the control circuit 31 is in a stopped state or a state in which the output of the drive signal is prohibited. Accordingly, since no switching signal is output from the control circuit 31, the step-down switching regulator 8 stops operating and no output voltage is output.

On the other hand, on the side of the series regulator 2, the output voltage of the error amplifier 21 is output and the switch SW1 is closed, so that the series regulator 2 is activated and the output voltage is output to the output terminal. 7 is output. As described above, in the second embodiment, when the load is heavy, the step-down switching regulator 8 is operated. The step-down switching regulator 8 has a current consumption of, for example, 100
Although it is as large as μA, the conversion efficiency of the output power with respect to the input power (power conversion efficiency) is as high as 90%, for example. For this reason, when the load is heavy, the load current increases. Therefore, the use of the step-down switching regulator 8 having high power conversion efficiency is effective, and the current consumption of the own device can be ignored because the load current is large.

On the other hand, when the load is light, the series regulator 2 is operated. The series regulator 2 has a small current consumption of, for example, 1 μA, but has a low power conversion efficiency of, for example, 60%. Therefore, when the load is light, even if the series regulator 2 is used, the low power conversion efficiency can be ignored because the current consumption of the series regulator 2 is small.

Therefore, according to the second embodiment, the current consumption can be reduced at a light load compared to a heavy load, so that when used under both a heavy load and a light load, the power consumption as a whole is reduced. Conversion efficiency can be improved. For this reason, particularly when using battery-operated electronic devices,
When operating in the standby state, useless consumption of the battery can be prevented, and the battery can be used for a long time.

In the above-described second embodiment, the step-down switching regulator 8 and the series regulator 2 are selectively operated, and the output voltage on the operation side is taken out. Since it is necessary to prevent the occurrence of a period in which no error occurs, a contrivance on this point will be described. First, a case where the operation of the step-down switching regulator 8 is switched to the operation of the series regulator 2 will be described.

At this time, since the light load determination signal S1 changes from "L" level to "H" level, this immediately causes the error amplifier 2 on the series regulator 2 side.
1 is in the output state, and the switch SW1 is closed. As a result, the series regulator 2 immediately starts operating. On the other hand, the change of the light load determination signal S1 is detected by an appropriate means, and when this change is detected, a timer is started and a predetermined time is counted, and an end signal is generated after the end of the counting. And, by this end signal,
The control circuit 31 of the step-down switching regulator 8 is set to a state where the operation is stopped or a state where the output of the drive signal is prohibited. As a result, the operation of the step-down switching regulator 8 stops after the operation of the series regulator 2 becomes stable.

With such an operation, when switching from the operation of the step-down switching regulator 8 to the operation of the series regulator 2, it is possible to prevent a period during which no output voltage is generated from occurring. Next, a case where the operation of the series regulator 2 is switched to the operation of the step-down switching regulator 8 will be described.

At this time, the light load determination signal S1 changes from “H” level to “L” level, which is converted by the inverter 3 and
Is input to the control circuit 31. Thereby, the control circuit 3
1 immediately shifts to an operating state or a state in which a drive signal can be output. Therefore, the step-down switching regulator 8 immediately starts operating.

On the other hand, the change of the light load determination signal S1 is detected by appropriate means, and when this change is detected, a timer is started and a predetermined time is counted, and an end signal is generated after the counting is completed. By this end signal, the output voltage of the error amplifier 21 on the series regulator 2 side is not output, and the switch SW1 is opened. Thus, the operation of the series regulator 2 stops after the operation of the step-down switching regulator 8 becomes stable.

With such an operation, when switching from the operation of the series regulator 2 to the operation of the step-down switching regulator 8, it is possible to prevent a period during which no output voltage is generated from occurring. Next, a third embodiment of the power supply device of the present invention will be described with reference to FIG.

As shown in FIG. 8, the third embodiment of the power supply device includes a charge-pump type step-down DC / DC converter 1 and a series regulator 2 having different properties, respectively. The step-down DC / DC converter 1 and the series regulator 2 are selectively operated based on the operation command signal S11 and the load detection signal S12 from the load detection circuit 42, and the output voltage on the operation side is output to the output terminal 7. It is designed to be taken out from.

A load (not shown) is connected to the third embodiment, and the load is controlled by a predetermined program by a microcomputer (processor) (not shown), for example. It has become. For this reason, when controlling the load, the change state of the load is known in advance or can be predicted.
For example, in the above-mentioned program, a program for generating an operation command signal S11 for selectively operating the step-down DC / DC converter 1 and the series regulator 2 in accordance with a predicted or expected load change state is included. I have.

Therefore, in the third embodiment, the microcomputer issues the operation command signal S1 during load control.
1 is generated, and the generated operation command signal S11 is input to an OR circuit (OR gate) 41.
The OR circuit 41 has the operation command signal S1
In addition to 1, a load detection signal S12 output when the load detection circuit 42 detects the magnitude of the load is input. Further, the output signal of the OR circuit 41 is supplied to the drive circuit 12 of the step-down DC / DC converter 1 and to the series regulator 2 via the inverter 43.

Therefore, in the third embodiment, the operation command signal S11 generated in advance according to the predicted or planned change in load and the load detection signal S12 from the load detection circuit 42 are logically output by the OR circuit 41. The sum processing is performed, and the step-down DC / DC converter 1 of the charge pump type and the series regulator 2 are selectively operated based on the processing result.

Since the configuration of the other parts of the third embodiment is substantially the same as that of the first embodiment shown in FIGS. 1 to 3, the same components are denoted by the same reference numerals. Detailed description is omitted. Next, the third configuration having such a configuration will be described.
The operation of the embodiment will be described with reference to FIGS.

In this example, a case in which the load of the third embodiment (power supply device) is controlled by a microcomputer (not shown) and the state of the load changes as shown in FIG. 9A will be described. Since the change in the load is known in advance, it is assumed that an operation command signal S11 corresponding to this change as shown in FIG. 9B is input from the microcomputer to the OR circuit 41.

Here, the operation command signal S11 corresponds to the signal shown in FIG.
As shown in (B), when a heavy load operation is commanded, the level is "H", and when a light load operation is commanded, the level is "L".
Level. Now, as shown in FIG. 9B, when the operation command signal S11 changes from “L” level to “H” level at time t1, the output of the OR circuit 41 becomes “L” as shown in FIG. 9D. The level changes from the “H” level to the “H” level, and the output of the inverter 43 changes from the “H” level to the “L” level as shown in FIG.

As a result, while the drive circuit 12 operates and the step-down DC / DC converter 1 enters the operating state, the series regulator 2 switches to the stop state and the step-down DC / DC converter
The output voltage of the / DC converter 1 is output from the output terminal 7. Therefore, step-down DC / DC converter 1 can wait for a heavy load in a stable operation.

Thereafter, as shown in FIG.
When the load is switched from a light load to a heavy load in Step 2, the heavy load can be driven by the step-down DC / DC converter 1 with stable operation. As shown in FIG. 9 (C),
At time t3, the load detection signal S12 detected by the load detection circuit 42 changes from “L” level to “H” level, and at this time, the operation command signal S11 is at “H” level. Therefore, the operation states of the step-down DC / DC converter 1 and the series regulator 2 do not change.

Thereafter, as shown in FIG.
At 4, the load switches from heavy load to light and heavy load,
At this time, the operation command signal S11 is at "H" level.
Therefore, the operation states of the step-down DC / DC converter 1 and the series regulator 2 do not change. FIG.
As shown in FIG. 9B, when the operation command signal S11 changes from “H” level to “L” level at time t5, the output of the OR circuit 41 becomes “H” level as shown in FIG. To the “L” level and the inverter 4
9 changes from the “L” level to the “H” level as shown in FIG.

As a result, the operation of the drive circuit 12 is stopped and the step-down DC / DC converter 1 is switched to the stopped state, while the series regulator 2 is switched to the operating state and the output voltage of the series regulator 2 is changed to the output terminal 7. Will be output to At time t5, the load detection signal S12 detected by the load detection circuit 42 changes from “H” level to “L” level. Therefore, at time t5, even if the operation command signal S11 is not normal, the operation according to the load can be performed.

Thereafter, by repeating such an operation, the step-down DC / DC converter 1 is changed according to the state of the load.
And the series regulator 2 selectively operate. As described above, according to the third embodiment, similarly to the first embodiment, the current consumption can be reduced at a light load, and the power conversion efficiency can be improved as a whole. Further, in the third embodiment, the step-down DC / DC converter 1 and the series regulator 2 are selectively used by using an operation command signal S11 generated in advance in accordance with a predicted or planned change in load. It was operated, and the output voltage on the operation side was taken out. For this reason, the step-down DC / DC converter 1 and the series regulator 2 can be appropriately selected and operated according to a change in load.

Further, in the third embodiment, the step-down DC /
The selective operation of the DC converter 1 and the series regulator 2 is controlled using the load detection signal S12 in addition to the operation command signal S11. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation command signal S11 is used. Next, a fourth embodiment of the power supply device of the present invention will be described with reference to FIG.

As shown in FIG. 10, the fourth embodiment of the power supply device includes a step-down switching regulator 8 and a series regulator 2 having different characteristics, and an operation command signal S11 input to a control terminal 44. The step-down switching regulator 8 and the series regulator 2 are selectively operated based on the load detection signal S12 detected by the load detection circuit 42 and the output voltage of the operation side is taken out from the output terminal 7. is there.

In the fourth embodiment, similarly to the third embodiment, a microcomputer (not shown) generates an operation command signal S11 similar to the above during the load control, and the generated operation command signal S11 is generated. The signal S11 is the OR circuit 4
1 is input. In addition to the operation command signal S11, a load detection signal S12 output by the load detection circuit 42 detecting the magnitude of the load is input to the OR circuit 41. Further, the output signal of the OR circuit 41 is supplied to the series regulator 2 via the inverter 43 while being supplied to the step-down switching regulator 8.

Therefore, in the fourth embodiment, the operation command signal S11 generated in advance according to the predicted or planned change in load and the load detection signal S12 from the load detection circuit 42 are logically output by the OR circuit 41. The sum processing is performed, and the step-down switching regulator 8 and the series regulator 2 are selectively operated based on the processing result.

Since the configuration of the other parts of the fourth embodiment is substantially the same as that of the second embodiment shown in FIGS. 6 and 7, the same components are denoted by the same reference numerals. Detailed description is omitted. Next, the operation of the fourth embodiment having such a configuration will be described with reference to FIGS.

In this example, the case where the load of the fourth embodiment (power supply device) is controlled by a microcomputer (not shown) and the state of the load changes as shown in FIG. 11A will be described. Since the change in the load is known in advance, it is assumed that an operation command signal S11 corresponding to this change as shown in FIG. 11B is input from the microcomputer to the OR circuit 41.

Here, the operation command signal S11 is the signal shown in FIG.
As shown in (B), when a heavy load operation is commanded, the level is "H", and when a light load operation is commanded, the level is "L".
Level. Now, as shown in FIG. 11B, when the operation command signal S11 changes from the “L” level to the “H” level at the time t1, the output of the OR circuit 41 becomes “L” as shown in FIG. 11D. The level changes from the “H” level to the “H” level, and the output of the inverter 43 changes from the “H” level to the “L” level as shown in FIG.

Therefore, while the step-down switching regulator 8 is operating, the series regulator 2 is switched to the stop state, and the output voltage of the step-down switching regulator 8 is output to the output terminal 7.
Therefore, the step-down switching regulator 8 can stand by for a heavy load while its operation is stable. Then, FIG.
As shown in FIG. 1A, when the load switches from a light load to a heavy load at time t2, the step-down switching regulator 8 with stable operation can drive the heavy load.

As shown in FIG. 11C, at time t3, the load detection signal S12 detected by the load detection circuit 42 is detected.
Changes from the “L” level to the “H” level. At this time, the operation command signal S11 is at the “H” level. Therefore, the operation state of the step-down switching regulator 8 does not change. Thereafter, as shown in FIG. 11A, at time t4, the load switches from the heavy load to the light / heavy load. At this time, the operation command signal S11 is at the “H” level. Therefore, the step-down switching regulator 8
And the series regulator 2 do not change their operation states.

As shown in FIG. 11B, at time t5, the operation command signal S11 changes from the "H" level to the "L" level.
When the level changes to the level, the output of the OR circuit 41 is changed as shown in FIG.
Changes from "H" level to "L" level,
The output of inverter 43 changes from "L" level to "H" level as shown in FIG. For this reason,
While the step-down switching regulator 8 switches to the stop state, the series regulator 2 switches to the operating state, and the output voltage of the series regulator 2 is changed to the output terminal 7.
Will be output from

At time t5, the load detection signal S12 detected by the load detection circuit 42 changes from "H" level to "L" level. For this reason, at time t5, even if the operation command signal S11 is not normal,
Can operate according to load. Thereafter, by repeating such operations, the step-down switching regulator 8 and the series regulator 2 selectively operate according to the state of the load.

As described above, according to the fourth embodiment, similarly to the second embodiment, the current consumption can be reduced at light load, and the power conversion efficiency can be improved as a whole. Further, in the fourth embodiment, the step-down switching regulator 8 and the series regulator 2 are selectively operated using the operation command signal S11 generated in advance in accordance with a predicted or planned change in load. The output voltage of the operation side is taken out. Therefore, the step-down switching regulator 8 and the series regulator 2 are
The operation can be appropriately selected according to a change in load.

Further, in the fourth embodiment, the selective operation of the step-down switching regulator 8 and the series regulator 2 is controlled by using the load detection signal S12 in addition to the operation command signal S11. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation command signal S11 is used. Next, a fifth embodiment of the power supply device of the present invention will be described with reference to FIG.

As shown in FIG. 12, the fifth embodiment of the power supply device includes a charge pump type step-down DC / DC converter 1 having different properties, and a series regulator 2A. While operating, the step-down DC / DC converter 1
The operation is performed according to the load determination signal S21 input to the control terminal. Therefore, the load determination signal S21 is output from the drive circuit 1 of the step-down DC / DC converter 1
2 is supplied.

Here, the load determination signal S21 is a signal corresponding to the magnitude of the load, for example, a signal having an "H" level when the load is large and an "L" level when the load is small. . Step-down DC / DC converter 1
Has the same configuration as the step-down DC / DC converter 1 shown in FIG. The series regulator 2A is substantially the same as the series regulator 2 shown in FIG. The difference is that the switch SW1 in FIG. 3 is omitted, and the supply of the light load determination signal S1 to the error amplifier 21 in FIG. 3 is omitted.

Further, the series regulator 2A and the step-down DC / DC converter 1 have an output voltage of the series regulator 2A which operates at all times is slightly lower than the output voltage of the step-down DC / DC converter 1 which is operated as required. It is configured to be smaller. For example, step-down type D
When the output voltage of the C / DC converter 1 is 3.0 [V], the output voltage of the series regulator 2A becomes 3.0
It is configured to be smaller by several tens [mV] from [V]. The reason will be described in an operation described later.

Next, the operation of the fifth embodiment having such a configuration will be described with reference to FIGS. First, the load determination signal S21 switches from the "H" level indicating that the load is a heavy load to the "L" level indicating that the load is a light load, and the operation of the step-down DC / DC converter 1 is stopped. The case where the operation is switched to only the series regulator 2A will be described. Step-down DC /
It is assumed that the DC converter 1 outputs, for example, a set value of 3.0 V.

In this case, the series regulator 2A
Is operating all the time, the error amplifier 21 shown in FIG. 3 is also operating. The set value of the output of the series regulator 2A is set to be several tens mV smaller than 3.0V. Therefore, the error amplifier 21 shown in FIG.
MOS transistor Q21 for output although operating
Waiting with the switch off.

When the load determination signal S21 changes from "H" level to "L" level, the step-down DC / DC converter 1 stops operating, and when the output voltage Vout drops to the set value of the series regulator 2A, the error amplifier 21 turns on the MOS transistor Q21, and the series regulator 2A maintains its output set value. As described above, since the error amplifier 21 always operates, the time from startup to stabilization is extremely short, and a drop in output can be prevented.

Next, a case where load determination signal S21 switches from "L" level to "H" level and the operation of step-down DC / DC converter 1 is started will be described.
In this way, when the step-down DC / DC converter 1 is started, the series regulator 2A operates until the output voltage Vout exceeds the set value of the series regulator 2A (a value set so as to be several tens mV smaller than 3.0 V). I have. However, when the output exceeds the set value while the step-down DC / DC converter 1 raises its output to 3 V, the series regulator 2A can automatically turn off the MOS transistor Q21 by the error amplifier 21.

As described above, the period from the activation of the step-down DC / DC converter 1 to the stabilization of the output is supplemented by the operation of the series regulator 2A, thereby eliminating the output drop. As described above, according to the fifth embodiment, similarly to the first embodiment, the current consumption can be reduced at a light load, and the power conversion efficiency can be improved as a whole.

Further, according to the fifth embodiment, when the step-down DC / DC converter starts or stops its operation, it is possible to prevent the output from dropping. Next, a sixth embodiment of the power supply device of the present invention will be described with reference to FIG. A sixth embodiment of this power supply device is shown in FIG.
As shown in FIG. 7, the power supply includes a step-down switching regulator 8 and a series regulator 2A having different characteristics, and the series regulator 2A is always operated, and the step-down switching regulator 8 is connected to a load determination signal input to a control terminal 45. The operation is performed according to S21. For this reason, the same load determination signal S21 as in the fifth embodiment is supplied to the step-down switching regulator 8.

The step-down switching regulator 8 has the same configuration as the step-down switching regulator 8 shown in FIG. The series regulator 2A is configured similarly to the series regulator 2A of the fifth embodiment. Further, the series regulator 2A and the step-down switching regulator 8 are configured such that the output voltage of the series regulator 2A that operates constantly is slightly smaller than the output voltage of the step-down switching regulator 8 that operates as needed. ing. For example, when the output voltage of the step-down switching regulator 8 is 3.0 [V], the output voltage of the series regulator 2A is 3.0.
It is configured such that it becomes smaller from 0 [V] to several tens [mV]. The reason will be described in an operation described later.

Next, the operation of the sixth embodiment having such a configuration will be described with reference to FIG. 3 and FIG. First, the load determination signal S21 switches from the "H" level indicating that the load is a heavy load to the "L" level indicating that the load is a light load, and the operation of the step-down switching regulator 8 is stopped. A case where the operation is switched to the operation of only the regulator 2A will be described. The step-down switching regulator 8 has, for example, a set value of 3.
It is assumed that 0 V is output.

In this case, the series regulator 2A
Is operating all the time, the error amplifier 21 shown in FIG. 3 is also operating. The set value of the output of the series regulator 2A is set to be several tens mV smaller than 3.0V. Therefore, the error amplifier 21 shown in FIG.
MOS transistor Q21 for output although operating
Waiting with the switch off.

When the load determination signal S21 changes from "H" level to "L" level, the step-down switching regulator 8 stops operating, and when the output voltage Vout drops to the set value of the series regulator 2A, the error amplifier 2
1 turns on the MOS transistor Q21 and the series regulator 2A maintains its output set value. in this way,
Since the error amplifier 21 always operates, the time from startup to stabilization is extremely short, and a drop in output can be prevented.

Next, the case where the load determination signal S21 switches from "L" level to "H" level and the operation of the step-down switching regulator 8 is started will be described below. As described above, when the step-down switching regulator 8 is started, the series regulator 2A operates until the output voltage Vout exceeds the set value of the series regulator 2A (a value set to be several tens mV smaller than 3.0 V). However, when the step-down switching regulator 8 exceeds its set value in the process of raising its output to 3 V, the series regulator 2A is automatically turned on by the error amplifier 21 by the MOS transistor Q2.
One can be turned off.

As described above, the period from the start of the step-down switching regulator 8 to the stabilization of the output is supplemented by the operation of the series regulator 2A, thereby eliminating the output drop. As described above, according to the sixth embodiment, as in the second embodiment, the current consumption can be reduced at light load, and the power conversion efficiency can be improved as a whole.

According to the sixth embodiment, when the step-down switching regulator starts or stops its operation, it is possible to prevent the output from dropping. Next, a seventh embodiment of the power supply device of the present invention will be described with reference to FIG. As shown in FIG. 14, the seventh embodiment of the power supply device includes a charge pump type step-down DC / DC converter 1 having different properties and a series regulator 2A, and always operates the series regulator 2A. The operation of the step-down DC / DC converter 1 is controlled by controlling the operation control signal S31 input to the control terminal 53 and the load determination signal S3 from the load detection circuit 52.
2 is performed.

The step-down DC / DC converter 1 has the same configuration as the step-down DC / DC converter 1 shown in FIG. The series regulator 2A has the same configuration as the series regulator 2A of the fifth embodiment. Furthermore, series regulator 2A and step-down DC /
The DC converter 1 has the same configuration as the fifth embodiment.

In the seventh embodiment, a load (not shown) is connected, and the load is controlled by, for example, a microcomputer (processor) (not shown) by a predetermined program. It has become. For this reason, when controlling the load, the change state of the load is known in advance or can be predicted.
For example, the above-mentioned program includes a program for generating an operation control signal S31 for turning on / off the step-down DC / DC converter 1 according to a predicted or expected load change state.

Therefore, in the seventh embodiment, the microcomputer controls the operation control signal S3 during load control.
1 is generated, and the generated operation control signal S31 is input to the OR circuit 51. In addition to the operation control signal S11, a load detection signal S32 output by the load detection circuit 52 detecting the magnitude of the load is input to the OR circuit 51.
Further, the output signal of the OR circuit 51 is a step-down DC / DC
The power is supplied to the drive circuit 12 of the converter 1.

Therefore, in the seventh embodiment, the operation control signal S31 generated in advance according to the predicted or planned change in load and the load detection signal S32 from the load detection circuit 52 are logically output by the OR circuit 51. The sum processing is performed, and the charge pump type step-down DC / DC converter 1 is controlled based on the processing result. Next, the operation of the seventh embodiment having such a configuration will be described with reference to FIG.
This will be described with reference to FIG.

In the seventh embodiment, when the power is turned on, the series regulator 2A always operates. On the other hand, the operation of the step-down DC / DC converter 1 is controlled in accordance with the operation control signal S31 and the load detection signal S32, and the operation will be described below. In this example, a case will be described in which the load of the seventh embodiment (power supply device) is controlled by a microcomputer (not shown), and the state of the load changes as shown in FIG. Since this change in load is known in advance, the operation control signal S3 as shown in FIG.
1 is input to the OR circuit 51 from the microcomputer.

Here, the operation control signal S31 is
As shown in (B), when a heavy load operation is commanded, the level is "H", and when a light load operation is commanded, the level is "L".
Level. Now, as shown in FIG. 15B, when the operation control signal S31 changes from the “L” level to the “H” level at the time t1, the output of the OR circuit 51 becomes “L” as shown in FIG. The level changes from “H” level to “H” level.

Therefore, the drive circuit 12 operates to bring the step-down DC / DC converter 1 into an operating state. Therefore, step-down DC / DC converter 1 can stand by for a heavy load while its operation is stable. Then, FIG.
As shown in (A), when the load switches from a light load to a heavy load at time t2, the step-down DC / DC with stable operation is operated.
The DC converter 1 can drive the heavy load.

As shown in FIG. 15C, at time t3, the load detection signal S32 detected by the load detection circuit 52 is detected.
Changes from the “L” level to the “H” level. At this time, the operation control signal S31 is at the “H” level. For this reason, the operation state of the step-down DC / DC converter 1 does not change. Thereafter, as shown in FIG. 15A, at time t4, the load switches from the heavy load to the light / heavy load. At this time, the operation control signal S31 is at the “H” level. For this reason, the operation state of the step-down DC / DC converter 1 does not change.

As shown in FIG. 15B, at time t5, the operation control signal S31 changes from the "H" level to the "L" level.
When the output level of the OR circuit 51 changes to the level shown in FIG.
As shown in (D), the level changes from “H” level to “L” level. As a result, the operation of the drive circuit 12 stops, the step-down DC / DC converter 1 switches to the stop state, and the output voltage of the series regulator 2A is
Will be output to

At time t5, the load detection signal S32 detected by the load detection circuit 52 changes from "H" level to "L" level. For this reason, at time t5, even if the operation control signal S31 is not normal,
Can operate according to load. Thereafter, by repeating such an operation, the step-down DC / D
The C converter 1 operates or stops.

As described above, according to the seventh embodiment, similarly to the first embodiment, the current consumption can be reduced at light load, and the power conversion efficiency can be improved as a whole. In the seventh embodiment, the operation of the step-down DC / DC converter 1 is controlled using the operation control signal S31 generated in advance according to a predicted or planned change in load. . For this reason, the control operation of the step-down DC / DC converter 1 can be appropriately operated according to a change in load.

Further, in the seventh embodiment, the step-down type DC /
The control operation of the DC converter 1 is performed using the load detection signal S32 in addition to the operation control signal S31.
Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation control signal S31 is used. Next, an eighth embodiment of the power supply device of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

As shown in FIG. 16, the eighth embodiment of the power supply device includes a step-down switching regulator 8 and a series regulator 2A, which have different characteristics. The operation of the switching regulator 8 is controlled by an operation control signal S31 input to a control terminal 53,
This is performed according to the load determination signal S32 from the load detection circuit 52.

The step-down switching regulator 8 has the same configuration as the step-down switching regulator 8 shown in FIG. The series regulator 2A has the same configuration as the series regulator 2A of the fifth embodiment. Further, the series regulator 2A and the step-down switching regulator 8 are configured in the same manner as in the sixth embodiment.

In the eighth embodiment, similarly to the seventh embodiment, the microcomputer generates the operation control signal S31 similar to the above during the control of the load, and generates the operation control signal S31. Is input to the OR circuit 51. In addition to the operation control signal S11, the OR circuit 51 has a load detection signal S that is output when the load detection circuit 52 detects the magnitude of the load.
32 is input. Further, the output signal of the OR circuit 51 is supplied to the step-down switching regulator 8.
It is supplied to.

Therefore, in the eighth embodiment, the operation control signal S31 generated in advance according to a predicted or planned change in load and the load detection signal S32 from the load detection circuit 52 are logically output by the OR circuit 51. The sum processing is performed, and the operation of the step-down switching regulator 8 is controlled based on the processing result. Next, the operation of the eighth embodiment having such a configuration will be described with reference to FIGS.
This will be described with reference to FIG.

In the eighth embodiment, when the power is turned on, the series regulator 2A is always operating. On the other hand, the operation of the step-down switching regulator 8 is controlled according to the operation control signal S31 and the load detection signal S32, and the operation will be described below.
In this example, a case will be described in which the load of the eighth embodiment (power supply device) is controlled by a microcomputer (not shown), and the state of the load changes as shown in FIG. Because this change in load is known in advance,
In response to this, an operation control signal S31 as shown in FIG. 17B is input from the microcomputer to the OR circuit 51.

Here, the operation control signal S31 is the same as that shown in FIG.
As shown in (B), when a heavy load operation is commanded, the level is "H", and when a light load operation is commanded, the level is "L".
Level. Now, as shown in FIG. 17B, when the operation control signal S31 changes from “L” level to “H” level at time t1, the output of the OR circuit 51 becomes “L” as shown in FIG. 17D. The level changes from “H” level to “H” level.

Therefore, the step-down switching regulator 8 enters an operating state. Therefore, the step-down switching regulator 8 can wait for a heavy load while the operation is stable. Thereafter, as shown in FIG. 17A, when the load switches from a light load to a heavy load at time t2, the step-down switching regulator 8 with stable operation can drive the heavy load.

As shown in FIG. 17C, at time t3, the load detection signal S32 detected by the load detection circuit 52 is detected.
Changes from the “L” level to the “H” level. At this time, the operation control signal S31 is at the “H” level. Therefore, the operation state of the step-down switching regulator 8 does not change. Thereafter, as shown in FIG. 17A, at time t4, the load switches from the heavy load to the light / heavy load. At this time, the operation control signal S31 is at the “H” level. Therefore, the operation state of the step-down switching regulator 8 does not change.

As shown in FIG. 17B, at time t5, the operation control signal S31 changes from the "H" level to the "L" level.
When the level changes to the level, the output of the OR circuit 51 is changed as shown in FIG.
As shown in (D), the level changes from “H” level to “L” level. As a result, the step-down switching regulator 8 is switched to the stop state, and the series regulator 2
The output voltage of A is output to the output terminal 7.

At time t5, the load detection signal S32 detected by the load detection circuit 52 changes from "H" level to "L" level. For this reason, at time t5, even if the operation control signal S31 is not normal,
Can operate according to load. Thereafter, by repeating such an operation, the step-down switching regulator 8 operates or stops according to the state of the load.

As described above, according to the eighth embodiment, as in the second embodiment, the current consumption can be reduced at light load, and the power conversion efficiency can be improved as a whole. In the eighth embodiment, the control operation of the step-down switching regulator 8 is performed using the operation control signal S31 generated in advance according to a predicted or planned change in load. Therefore, the control operation of the step-down switching regulator 8 can be appropriately performed according to the change in the load.

Further, in the eighth embodiment, the control operation of the step-down switching regulator 8 is controlled by the operation control signal S3.
In addition to 1, the load detection signal S32 is used. Therefore, a more reliable and stable operation can be performed as compared with the case where only the operation control signal S31 is used.

[0139]

As described above, according to the present invention,
It is possible to provide a power supply device in which current consumption can be reduced at a light load and power conversion efficiency is improved as a whole.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a power supply device of the present invention.

FIG. 2 is a circuit diagram showing a specific configuration of a step-down charge pump circuit.

FIG. 3 is a circuit diagram showing a specific configuration of a series regulator.

FIG. 4 is an explanatory diagram illustrating an operation example of a step-down charge pump circuit.

FIG. 5 is an explanatory diagram illustrating another operation example of the step-down charge pump circuit.

FIG. 6 is a block diagram illustrating a configuration of a power supply device according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram showing a specific configuration of a step-down switching regulator.

FIG. 8 is a block diagram illustrating a configuration of a power supply device according to a third embodiment of the present invention.

FIG. 9 is a waveform chart of each part of the third embodiment.

FIG. 10 is a block diagram illustrating a configuration of a power supply device according to a fourth embodiment of the present invention.

FIG. 11 is a waveform chart of each part of the fourth embodiment.

FIG. 12 is a block diagram illustrating a configuration of a power supply device according to a fifth embodiment of the present invention.

FIG. 13 is a block diagram illustrating a configuration of a power supply device according to a sixth embodiment of the present invention.

FIG. 14 is a block diagram illustrating a configuration of a power supply device according to a seventh embodiment of the present invention.

FIG. 15 is a waveform chart of each part of the seventh embodiment.

FIG. 16 is a block diagram showing a configuration of an eighth embodiment of the power supply device of the present invention.

FIG. 17 is a waveform chart of each part of the eighth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charge-pump type step-down DC / DC converter 2, 2A series regulator 4 Input terminal 6 Control input terminal 7 Output terminal 8 Step-down switching regulator 11 Step-down charge pump circuit 12 Drive circuit 21 Error amplifier 31 Control circuit 41, 51 or Circuit 42, 52 Load detection circuit

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Claims (18)

[Claims] 1. A charge-pump type DC for converting an input voltage into a predetermined output voltage by utilizing charge and discharge of a capacitor.
A DC / DC converter, and a series regulator that inputs the input voltage and continuously controls the output voltage so that its own output voltage becomes a predetermined voltage. The DC / DC converter and the series regulator A power supply device which is selectively operated in accordance with the magnitude of a load to extract an output voltage on the operation side. 2. The method according to claim 1, wherein the DC / DC converter and the series regulator are selectively operated in accordance with the magnitude of the load, and a signal for extracting an output voltage on the operation side is externally input. The power supply device according to claim 1, further comprising: a control input terminal. 3. When the load is large, the DC / D
The power supply device according to claim 1, wherein the C converter is operated, and the series regulator is operated when the load is small. 4. A switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage; and inputting the input voltage and continuously changing the output voltage so that its own output voltage becomes a predetermined voltage. A power supply, comprising: a series regulator for controlling the power supply; and selectively operating the switching regulator and the series regulator according to the magnitude of a load to extract an output voltage on the operation side. apparatus. 5. A signal for selectively operating the switching regulator and the series regulator in accordance with the magnitude of the load so as to externally input a signal for extracting an output voltage on the operation side, and a control input for the signal. The power supply device according to claim 4, further comprising a terminal. 6. The system according to claim 4, wherein the switching regulator is operated when the load is large, and the series regulator is operated when the load is small. The power supply as described. 7. A charge-pump type DC for converting an input voltage to a predetermined output voltage by utilizing charge and discharge of a capacitor.
/ DC converter, and a series regulator that inputs the input voltage and continuously controls the output voltage so that its own output voltage becomes a predetermined voltage. The DC / DC converter and the series regulator A power supply device that selectively operates according to an operation command signal generated in advance based on a predicted or planned change in load, and extracts an output voltage of the operation side. 8. A selective operation of the DC / DC converter and the series regulator is performed using a load detection signal obtained by detecting a magnitude of a load, in addition to the operation command signal. The power supply device according to claim 7, wherein: 9. When the load is large, the DC / D
9. The power supply device according to claim 7, wherein a C converter is operated, and when the load is small, the series regulator is operated. 10. A switching regulator that switches an input voltage and converts the input voltage to a predetermined output voltage. The switching regulator receives the input voltage and continuously changes its output voltage so that its own output voltage becomes a predetermined voltage. And a series regulator for controlling the switching regulator, the switching regulator and the series regulator are selectively operated in accordance with an operation command signal generated in advance based on a predicted or expected change in load, and the operation side of the A power supply device for extracting an output voltage. 11. The selective operation of the switching regulator and the series regulator is performed using a load detection signal obtained by detecting a magnitude of a load, in addition to the operation command signal. The power supply device according to claim 10, wherein: 12. The system according to claim 10, wherein the switching regulator is operated when the load is large, and the series regulator is operated when the load is small. The power supply as described. 13. A charge-pump type D that converts an input voltage into a predetermined output voltage by utilizing charge and discharge of a capacitor.
A C / DC converter, and a series regulator that inputs the input voltage and continuously controls the output voltage so that its own output voltage becomes a predetermined voltage, and always operates the series regulator.
A power supply device wherein the DC / DC converter is operated according to the magnitude of a load. 14. A switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage; and a step of inputting the input voltage and continuously outputting the output voltage so that its own output voltage becomes a predetermined voltage. And a series regulator that controls the power supply, and always operates the series regulator.
A power supply device, wherein the switching regulator is operated according to the magnitude of a load. 15. A charge-pump type D that converts an input voltage into a predetermined output voltage by utilizing charging and discharging of a capacitor.
A C / DC converter, and a series regulator that inputs the input voltage and continuously controls the output voltage so that its own output voltage becomes a predetermined voltage, and always operates the series regulator.
A power supply device, wherein the operation of the DC / DC converter is controlled in accordance with an operation control signal generated in advance based on a predicted or planned change in load. 16. The control of the operation of the DC / DC converter is performed using a load detection signal obtained by detecting a magnitude of a load in addition to the operation control signal. The power supply device according to claim 15, wherein 17. A switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage; and inputting the input voltage and continuously outputting the output voltage so that its own output voltage becomes a predetermined voltage. And a series regulator that controls the power supply, and always operates the series regulator.
A power supply device, wherein the operation of the switching regulator is controlled in accordance with an operation control signal generated in advance based on a predicted or planned change in load. 18. The operation of the switching regulator is controlled using a load detection signal obtained by detecting a magnitude of a load, in addition to the operation control signal. The power supply device according to claim 17.