JP3525930B2 - Power supply - Google Patents

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 capable of reducing its own current consumption at the time of a light load, eliminating waste of power, and improving power conversion efficiency as a whole.

[0002]

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

A switching regulator switches an input voltage and converts the input voltage into 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, the charge pump type DC / DC converter is designed to operate even if the load or the like changes. The current consumption was the same. For this reason, there is no waste of electric power when the load is heavy, but when the load is light, the capacity becomes excessive and there is a waste of electric power, and there is a problem in that the conversion efficiency of the electric power decreases as a whole.

On the other hand, a switching regulator consumes a large amount of its own current but has a high power conversion efficiency. Therefore, when the load is heavy, the high power conversion efficiency is effective. However, there is a problem that the conversion efficiency of electric power is lowered as a whole. Therefore,
SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide a power supply device capable of reducing its own current consumption at the time of a light load and improving the conversion efficiency of electric power as a whole.

[0006]

A power supply device according to the present invention receives a first control signal for controlling switching between driving and stopping,
A DC / DC converter that converts a first input voltage into a predetermined output voltage and a second control signal that controls switching between driving and stopping are input, and the second input voltage is output so as to have a predetermined output voltage. A power supply device comprising a series regulator for continuously controlling a voltage, wherein the series regulator has an input terminal to which the second input voltage is input,
An output terminal for outputting an output voltage, a transistor, an error amplifier, a first resistor, and a second resistor are included, the input terminal is connected to one end of the transistor, and the other end of the transistor is connected to the other end. The error amplifier is connected to the output terminal and is also connected to a terminal for a third voltage via the first resistor and the second resistor, and the error amplifier includes the first resistor and the second resistor. The connection point voltage with and the reference voltage,
A power supply device, wherein an enable signal is input, and the output of the error amplifier is connected to the gate of the transistor. In the power supply device according to the present invention, when the enable signal and the second control signal are the same signal and the second control signal is at a level indicating drive, the error amplifier operates as the first resistor. An output corresponding to a comparison between a connection point voltage with the second resistor and a reference voltage is applied to the gate of the transistor to control the on-resistance of the transistor and output a predetermined voltage. To do. The power supply device according to the present invention is characterized by having a switch element between the second resistor and the terminal for the third voltage. The DC / DC converter of the power supply device according to the present invention is a charge pump type step-down DC / DC converter. The DC / DC converter of the power supply device according to the present invention is a switching regulator.

According to the present invention, the DC / DC converter and the series regulator are selectively operated according to the magnitude of the load, and a signal for extracting the output voltage of the operating side is externally input. A control input terminal therefor is provided.

The present invention is characterized in that the DC / DC converter is operated when the load is large, and the series regulator is operated when the load is small. in this way,
A DC / DC converter combining a charge pump type DC / DC converter with different characteristics and a series regulator
The converter and the series regulator are selectively operated according to the size of the load to extract the output voltage on the operating side.

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

On the other hand, when the load is light, the series regulator is operated. Although the series regulator consumes less current, it has low power conversion efficiency. Therefore, at light load, even if a series regulator is used, its own current consumption is small.
The low efficiency of the power conversion can be ignored. Therefore, when the load is light, the current consumption can be reduced as compared to the case where the load is heavy, so that the power conversion efficiency can be improved as a whole when used in both heavy load and light load.

According to the present invention, a switching regulator that switches an input voltage and converts the input voltage into a predetermined output voltage, and the input voltage is input, and the output voltage of the switching regulator is adjusted so that its own output voltage becomes a predetermined voltage. And a series regulator for continuously controlling the switching regulator and the series regulator to selectively operate the switching regulator and the series regulator according to the magnitude of the load to extract the output voltage on the operating side. To do.

According to the present invention, the switching regulator and the series regulator are selectively operated according to the magnitude of the load, and a signal for extracting the output voltage on the operating side is input from the outside. It is characterized in that a control input terminal is provided.

The present invention is characterized in that the switching regulator is operated when the load is large, and the series regulator is operated when the load is small. As described above, the switching regulator and the series regulator having different characteristics are combined, and the switching regulator and the series regulator are selectively operated according to the magnitude of the load to extract the output voltage on the operating side.

Specifically, the switching regulator is operated when the load is heavy. Although the switching regulator consumes a large amount of current, it has a high conversion efficiency of output power with respect to input power. Therefore, when the load is heavy, the load current increases. Therefore, it is effective to use a switching regulator with high power conversion efficiency, and its own current consumption can be ignored because the load current is large.

On the other hand, when the load is light, the series regulator is operated. Although the series regulator consumes less current, it has low power conversion efficiency. Therefore, at light load, even if a series regulator is used, its own current consumption is small.
The low efficiency of the power conversion can be ignored. Therefore, when the load is light, the current consumption can be reduced as compared to the case where the load is heavy, so that the power conversion efficiency can be improved as a whole when used in both heavy load and light load.

According to the present invention, a charge pump type DC / DC converter for converting an input voltage into a predetermined output voltage by charging / discharging a capacitor, and the input voltage is inputted, and its own output voltage is a predetermined voltage. And a series regulator for continuously controlling its output voltage so that the DC / DC converter and the series regulator are operated according to an operation command signal generated in advance based on a predicted or expected change in load. It is characterized in that it is selectively operated to take out the output voltage on the operating side.

According to the present invention, the selective operation of the DC / DC converter and the series regulator is performed by using a load detection signal obtained by detecting the magnitude of the load in addition to the operation command signal. It is characterized by being. Further, when the load is large, the DC / DC converter is operated, and when the load is small, the series regulator is operated.

According to the present invention, the DC / DC converter and the series regulator are selectively operated according to the operation command signal generated in advance based on the predicted or expected change in the load, and the output voltage on the operating side is changed. I took it out. Therefore, the DC / DC converter and the series regulator can be appropriately selected and operated according to the change of the load.

Furthermore, the selective operation of the DC / DC converter and the series regulator can be performed in addition to the operation command signal.
The load detection signal obtained by detecting the magnitude of the load is used. 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 the present invention, a switching regulator for switching an input voltage and converting the input voltage to a predetermined output voltage, and inputting the input voltage, the output voltage thereof is adjusted so that its own output voltage becomes a predetermined voltage. And a series regulator that continuously controls the switching regulator and the series regulator, selectively operating the switching regulator and the series regulator according to an operation command signal generated in advance based on a predicted or expected change in load, and the operation thereof. It is characterized in that the output voltage on the side is taken out.

According to the present invention, the selective operation of the switching regulator and the series regulator is performed by using a load detection signal obtained by detecting the magnitude of the load, in addition to the operation command signal. It is characterized by that. Further, when the load is large, the switching regulator is operated, and when the load is small, the series regulator is operated.

In the present invention, the switching regulator and the series regulator are selectively operated according to the operation command signal generated in advance based on the predicted or expected change in the load, and the output voltage on the operating side is taken out. I chose Therefore, the switching regulator and the series regulator can be appropriately selected and operated according to the change of the load.

Further, the switching regulator and the series regulator are selectively operated by using a load detection signal obtained by detecting the magnitude of the load in addition to the operation command signal. 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 the present invention, a charge pump type DC / DC converter for converting an input voltage into a predetermined output voltage by using charging / discharging of a capacitor, and inputting the input voltage, the output voltage of its own is a predetermined voltage. And a series regulator for continuously controlling its output voltage so that the series regulator is always operated and the DC / DC converter is operated according to the magnitude of the load. It is what

As described above, according to the present invention, DC having different properties is used.
By combining a / DC converter and a series regulator, for example, a series regulator with a small capacity is always operated, and a DC / DC converter with a large capacity is operated according to the size of the load. Therefore, the current consumption can be reduced when the load is light, and the power conversion efficiency can be improved as a whole.

According to the present invention, a switching regulator that switches an input voltage and converts the input voltage into a predetermined output voltage, and the input voltage is input, and the output voltage thereof is adjusted to a predetermined voltage. And a series regulator for continuously controlling the switching regulator, the series regulator is constantly operated, and the switching regulator is operated according to the magnitude of the load.

As described above, according to the present invention, the switching regulator and the series regulator having different characteristics are combined so that, for example, the series regulator having a small capacity is always operated, and the switching regulator having a large capacity is operated according to the magnitude of the load. did.
Therefore, the current consumption can be reduced when the load is light, and the power conversion efficiency can be improved as a whole.

According to the present invention, 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 the input voltage is inputted, and its own output voltage is a predetermined voltage. And a series regulator for continuously controlling its output voltage so that the series regulator is always operated, and the operation of the DC / DC converter is controlled based on a predicted or expected change in load. It is characterized in that the operation is performed according to an operation control signal generated in advance.

According to the present invention, the control of the operation of the DC / DC converter is performed using a load detection signal obtained by detecting the magnitude of the load, in addition to the operation control signal. It is characterized by. In this manner, the DC / DC converter and the series regulator having different characteristics are combined to operate the series regulator at all times, and the operation control of the DC / DC converter is generated in advance based on the predicted or expected load change. The operation control signal is used.
Therefore, the current consumption can be reduced at the time of a light load, the power conversion efficiency can be improved as a whole, and the DC / DC converter can be appropriately operated according to the change of the load.

Further, the operation of the DC / DC converter is controlled by using a load detection signal obtained by detecting the magnitude of the load in addition to the operation control signal.
Therefore, compared to the case where only the motion control signal is used,
A more reliable and stable operation can be performed. further,
A switching regulator that switches an input voltage and converts the input voltage to a predetermined output voltage, and a series that inputs the input voltage and continuously controls the output voltage so that its own output voltage becomes a predetermined voltage A regulator, and the series regulator is always operated, and the operation of the switching regulator is controlled according to an operation control signal generated in advance based on a predicted or expected change in load. It is characterized by.

The present invention is characterized in that the operation of the switching regulator is controlled using a load detection signal obtained by detecting the magnitude of the load, in addition to the operation control signal. It is what In this way, by combining a switching regulator with different characteristics and a series regulator, the series regulator is always operated, and the operation of the switching regulator is controlled in advance based on predicted or expected load changes. I tried to follow the signal. Therefore, the current consumption can be reduced when the load is light, the efficiency of power conversion can be improved as a whole, and the switching regulator can be appropriately operated according to the change in the load.

Further, in the present invention, the control of the operation of the switching regulator is performed using the load control 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]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a power supply device of the present invention will be described below 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 and a series regulator 2 which have different properties and are based on a light load determination signal S1. , The step-down DC / DC converter 1 and the series regulator 2 are selectively operated,
The output voltage of the operating side is taken out from the output terminal 7.

The step-down DC / DC converter 1 converts the input voltage Vin input to the input terminal 4 into a predetermined output voltage Vout by using the charging / 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 a switching MOS transistor Q as shown in FIG.
1-Q4 and a capacitor C1, a first charge pump circuit 11A, and a switching MOS transistor Q
Second charge pump circuit 12A including 11 to Q14 and capacitor C2, and first charge pump circuit 11A
And a second charge pump circuit 12A are connected to each other, and include a switch MOS transistor Q5 and an output capacitor C3.

More specifically, the MOS transistor Q
1, its source is connected to the input terminal 4, and its drain is 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 source of the transistor Q2 is connected to the drain of the MOS transistor Q1, and its drain is the output terminal 7
It is connected to the. Furthermore, 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 the source thereof is grounded. A capacitor C3 is connected between the output terminal 7 and the ground.

The MOS transistor Q11 has its source connected to the input terminal 4 and its drain connected to the capacitor C.
It is connected to the source of the MOS transistor Q13 via 2 and 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 and the drain is connected to the output terminal 7. Furthermore, the MOS transistor Q14
Has its drain connected to the source of the MOS transistor Q13 and its source grounded.

MOS transistors Q1 to Q5, Q11 to
A predetermined drive signal from the drive circuit 12 shown in FIG. 1 is input to each gate of 14, and the MOS transistors Q1 to Q5 and Q11 to 14 are on / off controlled by the 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 that can be set by the setting mode signal S1 is that the step-down charge pump circuit 11 is driven complementarily or non-complementarily, and the step-down ratio of the input voltage (for example, 1/1 times, 1/2 times). 2/3 times)
Is. Further, the drive circuit 12 is configured so that its operation is stopped or its output is prohibited based on an inversion 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.
While inputting n, the output voltage Vout is continuously controlled so that its own output voltage Vout becomes a predetermined voltage. For example, the output voltage Vout is configured as shown in FIG. That is, in this 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, the resistor R2, and the switch SW1 are connected in series. The error amplifier 21 outputs the output voltage Vout to the resistor R
The divided voltage divided by 1 and R2 is compared with the reference voltage, and the output voltage according to the comparison is applied to the gate of the MOS transistor Q21 to control the on-resistance of the MOS transistor Q21, and thereby the predetermined output is obtained. The voltage can be obtained.

The output voltage of the error amplifier 21 is on / off controlled by the light load determination signal S1 input to the control input terminal 6. Also, the switch SW1
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 "L" level, for example.
Therefore, the light load determination signal S1 is directly input to the error amplification circuit 21 and the switch SW1 of the series regulator 2 and is inverted to the “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 operating state or in a state capable of outputting a drive signal. Therefore, from the drive circuit 12, predetermined drive signals corresponding to the mode set by the setting mode signal S2 are transmitted 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 setting 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 prohibited and the switch S
Since W1 is in the open state, the series regulator 2
Does not work and no output voltage is generated. Next, when the load in 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 as it is
1 and the switch SW1 respectively, and is inverted to the “L” level by the inverter 3 to generate 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 the stopped state or the output of the drive signal is prohibited. Therefore, the drive circuit 12
Since each drive signal is not output, the step-down charge pump circuit 11 stops its operation and no output voltage is generated. 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 in operation and its output voltage is output to the output terminal 7. To be 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 a mode in which the step-down voltage is 1/1 times is set, which is a complementary operation, 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 during the first period and in the state shown in FIG. 4B during the second period. The operation of the period is repeated alternately.

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

On the other hand, in the second period, in the first charge pump circuit 11A, only the MOS transistors Q1 and Q4 are turned on by the drive circuit 12, and the input voltage Vi is increased.
The capacitor C2 is charged by n (see FIG. 4B). Further, 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).
(See (B)).

Next, in the complementary operation, the step-down voltage is 1 /
A 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. Then, the operation in the first period and the operation in the second period are alternately repeated. The detailed description is omitted here.

As described above, in the first embodiment, when the load is heavy, the charge pump type step-down DC type is used.
The DC / DC converter 1 is operated. Step-down DC
The current consumption of the / DC converter 1 is, for example, 100
Although as large as μA, the conversion efficiency of output power with respect to input power (efficiency of power conversion) is as high as 90%. Therefore, since the load current increases at the time of heavy load, it is effective to use the step-down DC / DC converter 1 having high power conversion efficiency, and its own consumption current can be ignored because the load current is large. it can.

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

Therefore, according to the first embodiment, the current consumption can be reduced when the load is light as compared with when the load is heavy. Therefore, when the load is used in both the heavy load and the light load, the total power consumption is reduced. The conversion efficiency can be improved. Therefore, especially when using an electronic device that operates on a battery,
When operating in a standby state, it is possible to prevent wasteful consumption of the battery and use the battery for a long time.

By the way, in the above-described first embodiment, the step-down DC / DC converter 1 and the series regulator 2 are selectively operated and the output voltage on the operating side is taken out. Since it is necessary to prevent a period in which no output voltage is generated, it will be described about a device in this respect. First, step-down DC
/ DC converter 1 operation to series regulator 2
The case of switching to the above operation will be described.

At this time, the light load determination signal S1 changes from the "L" level to the "H" level, so that the error amplifier 2 on the series regulator 2 side is immediately caused.
When the output voltage of 1 is output, 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 is detected, a timer (not shown) is activated to count a predetermined time,
An end signal is generated after the end of the counting. Then, the end signal causes the drive circuit 12 on the step-down DC / DC converter 1 side to be in the operation stopped state or 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.

By such an operation, the step-down DC / DC
When the operation of the converter 1 is switched to the operation of the series regulator 2, it is possible to prevent a period in which no output voltage is generated from occurring. Next, conversely, series regulator 2
The case of switching from the operation of 1 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 the "H" level to the "L" level, which is converted by the inverter 3 and input to the drive circuit 12 on the step-down DC / DC converter 1 side. . Therefore, the drive circuit 12 immediately shifts 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 the change is detected, a timer is activated to count a predetermined time, and an end signal is generated after the counting is completed. Then, this end signal causes the output voltage of the error amplifier 21 on the series regulator 2 side not to be output, and causes the switch SW1 to open. As a result, the series regulator 2 becomes stable after the operation of the step-down DC / DC converter 1 becomes stable.
The operation stops.

By such an operation, when the operation of the series regulator 2 is switched to the operation of the step-down DC / DC converter 1, it is possible to prevent a period in 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 this power supply device is provided with a step-down switching regulator 8 and a series regulator 2 having different properties,
The step-down switching regulator 8 and the series regulator 2 are selectively operated based on the light load determination signal S1, and the output voltage on the operating side is taken out from the output terminal 3.

The series regulator 2 is similar to the series regulator 2 shown in FIGS.
The step-down switching regulator 8 switches the input voltage and converts the input voltage into a predetermined output voltage, and has a configuration as shown in FIG. 7, for example.

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. Further, one end of the coil L1 is grounded via the diode D1, and the other end of the coil L1 is grounded via the capacitor C4. The control circuit 31 generates a switching signal in which the pulse frequency or pulse width changes according to the magnitude of the output voltage Vout, and the switching signal causes the MO signal.
The on / off control of the S transistor Q31 is performed so that a desired output voltage can be obtained.

Further, the control circuit 31 stops its operation or prohibits its output based on the inverted signal S3 obtained by inverting the light load determination signal S1 input from the control input terminal 6 by the inverter 3. There is. Next, the operation of 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 "L" level, for example.
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 the “H” level by the inverter 3, and the inverted signal S3 is inverted 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 its output is possible. Therefore, the step-down switching regulator 8 is in the operating state, and the 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 in the open state, the series regulator 2 does not generate an output voltage.

Next, when the load in 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 is inverted by the step-down switching regulator 8. It is input to the control circuit 31. As a result, on the step-down switching regulator 8 side, the control circuit 31 is in a stopped state or a state where the output of the drive signal is prohibited. Therefore, since the control circuit 31 does not output the switching signal, the step-down switching regulator 8 stops its operation and the output voltage is not output.

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

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

Therefore, according to the second embodiment, when the load is light, the current consumption of the self can be reduced as compared with the case where the load is heavy. The conversion efficiency can be improved. Therefore, especially when using an electronic device that operates on a battery,
When operating in a standby state, it is possible to prevent wasteful consumption of the battery and use the battery for a long time.

By the way, in the above-described second embodiment, the step-down switching regulator 8 and the series regulator 2 are selectively operated to extract the output voltage on the operating side. Therefore, when the operation is switched, the output voltage is changed. Since it is necessary to prevent the occurrence of the period in which no occurrence occurs, a device in this respect will be described. First, the 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, the light load determination signal S1 changes from the "L" level to the "H" level, so that the error amplifier 2 on the series regulator 2 side is immediately caused.
When 1 is in the output state, 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 it is detected, a timer is activated to count a predetermined time, and an end signal is generated after the counting is completed. And by this end signal,
The control circuit 31 on the side of the step-down switching regulator 8 is brought into 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 switching regulator 8 stops its operation after the operation of the series regulator 2 becomes stable.

By such an operation, when the operation of the step-down switching regulator 8 is switched to the operation of the series regulator 2, it is possible to prevent a period in which no output voltage is generated from occurring. Next, conversely, the 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 the "H" level to the "L" level, and this is converted by the inverter 3 to generate the step-down switching regulator 8.
Is input to the control circuit 31. As a result, 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 an appropriate means, and when this change is detected, the timer is started to count a predetermined time, and the end signal is generated after the end of the counting. Then, this end signal causes the output voltage of the error amplifier 21 on the series regulator 2 side not to be output, and causes the switch SW1 to open. As a result, the series regulator 2 stops its operation after the operation of the step-down switching regulator 8 becomes stable.

With such an operation, it is possible to prevent a period in which no output voltage is generated when the operation of the series regulator 2 is switched to the operation of the step-down switching regulator 8. 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 is provided with a charge pump type step-down DC / DC converter 1 and a series regulator 2 which have different properties and are input to a control terminal 44. Based on the operation command signal S11 and the load detection signal S12 from the load detection circuit 42, the step-down DC / DC converter 1 and the series regulator 2 are selectively operated, and the output voltage on the operation side is output to the output terminal 7 It is designed to be taken out from.

In addition, a load (not shown) is connected to the third embodiment, and the load is controlled by a predetermined program, for example, by a microcomputer (processor) not shown. It has become. Therefore, when controlling the load, the change state of the load can be known or predicted in advance.
For example, in the above 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 the predicted or expected load change state is included. There is.

Therefore, in the third embodiment, the microcomputer controls the operation command signal S1 during the load control.
1 is generated, and the generated operation command signal S11 is input to the OR circuit (OR gate) 41.
Further, the OR circuit 41 is provided with the operation command signal S1.
In addition to 1, the load detection signal S12 output by the load detection circuit 42 detecting 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 also to the series regulator 2 via the inverter 43.

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

Since the structure 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 designated by the same reference numerals. Detailed description thereof will be omitted. Next, a third structure having such a configuration
The operation of the embodiment will be described with reference to FIGS. 8 and 9.

In this example, the case where 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 this change in load is known in advance, it is assumed that the 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 is as shown in FIG.
As shown in (B), when commanding a heavy load operation, it is at “H” level, and when commanding a light load operation, “L” level.
It is assumed to be a level. Now, as shown in FIG. 9 (B), when the operation command signal S11 changes from the "L" level to the "H" level at time t1, the output of the OR circuit 41 becomes "L" as shown in FIG. 9 (D). The level changes 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, the drive circuit 12 operates to bring the step-down DC / DC converter 1 into the operating state, while the series regulator 2 switches to the stop state, and the step-down DC
The output voltage of the / DC converter 1 is output from the output terminal 7. Therefore, the step-down DC / DC converter 1 can stand by for a heavy load in a stable operation state.

After that, as shown in FIG. 9A, time t
When the load is switched from the light load to the heavy load in 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 the “L” level to the “H” level, but at this time, the operation command signal S11 is at the “H” level. Therefore, the operation state of the step-down DC / DC converter 1 and the series regulator 2 does not change.

After that, as shown in FIG. 9A, time t
In 4 the load switches from heavy to light and heavy,
At this time, the operation command signal S11 is at "H" level.
Therefore, the operation state of the step-down DC / DC converter 1 and the series regulator 2 does not change. Figure 9
As shown in (B), at time t5, when the operation command signal S11 changes from the "H" level to the "L" level, the output of the OR circuit 41 becomes the "H" level as shown in FIG. 9D. Changes from "L" level to the inverter 4
The output of No. 3 changes from "L" level to "H" level as shown in FIG. 9 (E).

Therefore, 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 the “H” level to the “L” level. Therefore, at time t5, the operation according to the load can be performed even when the operation command signal S11 is not normal.

After that, 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 operates selectively. As described above, according to the third embodiment, similarly to the first embodiment, the current consumption can be reduced when the load is light, 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 the operation command signal S11 which is generated in advance in accordance with the predicted or expected change in the load. It was operated and the output voltage on the operating side was taken out. Therefore, the step-down DC / DC converter 1 and the series regulator 2 can be appropriately selected and operated according to changes in the load.

Further, in the third embodiment, the step-down DC /
The selective operation control of the DC converter 1 and the series regulator 2 is performed by using the load detection signal S12 in addition to the operation command signal S11. Therefore, as compared with the case where only the operation command signal S11 is used, a more reliable and stable operation can be performed. 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 is provided with a step-down switching regulator 8 and a series regulator 2 which have different properties, 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 on the operating side is taken out from the output terminal 7. is there.

Further, in the fourth embodiment, as in the case of the third embodiment, the microcomputer (not shown) generates the operation command signal S11 similar to the above during the control of the load, and the generated operation command Signal S11 is OR circuit 4
1 is input. In addition to the operation command signal S11 described above, the OR circuit 41 is supplied with a load detection signal S12 that is output when the load detection circuit 42 detects the magnitude of the load. Further, the output signal of the OR circuit 41 is supplied to the step-down switching regulator 8 and also to the series regulator 2 via the inverter 43.

Therefore, in the fourth embodiment, the OR circuit 41 logically operates the operation command signal S11 generated in advance in accordance with the predicted or expected change in the load and the load detection signal S12 from the load detection circuit 42. 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.

The structure of the other parts of the fourth embodiment is substantially the same as that of the second embodiment shown in FIGS. 6 and 7, and therefore, the same components are designated by the same reference numerals. Detailed description thereof will be omitted. Next, the operation of the fourth embodiment having such a configuration will be described with reference to FIGS. 10 and 11.

In this example, 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. Since the change of the load is known in advance, it is assumed that the corresponding operation command signal S11 as shown in FIG. 11B is input from the microcomputer to the OR circuit 41.

Here, the operation command signal S11 is as shown in FIG.
As shown in (B), when commanding a heavy load operation, it is at “H” level, and when commanding a light load operation, “L” level.
It is assumed to be a level. Now, as shown in FIG. 11 (B), when the operation command signal S11 changes from the “L” level to the “H” level at time t1, the output of the OR circuit 41 becomes “L” as shown in FIG. 11 (D). The level changes 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 in the operating state, the series regulator 2 is switched to the stopped 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 in a stable operation state. Then, Figure 1
As shown in 1 (A), when the load is switched from the light load to the 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, but at this time, the operation command signal S11 is at the “H” level. Therefore, the step-down switching regulator 8 does not change its operating state. Thereafter, as shown in FIG. 11A, the load switches from the heavy load to the light heavy load at time t4, but at this time, the operation command signal S11 is at the “H” level. Therefore, the step-down switching regulator 8
The series regulator 2 does not change its operating state.

As shown in FIG. 11B, at time t5, the operation command signal S11 changes from "H" level to "L" level.
When the level is changed, the output of the OR circuit 41 is changed to that shown in FIG.
Change from "H" level to "L" level as shown in
The output of the inverter 43 changes from the "L" level to the "H" level as shown in FIG. For this reason,
The step-down switching regulator 8 is switched to the stop state, while the series regulator 2 is switched to the operating state, and the output voltage of the series regulator 2 is output 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. Therefore, even if the operation command signal S11 is not normal at time t5,
It can operate according to the load. After that, 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 when the load is light, and the power conversion efficiency can be improved as a whole. In addition, in the fourth embodiment, the step-down switching regulator 8 and the series regulator 2 are selectively operated by using the operation command signal S11 that is generated in advance in accordance with the predicted or expected change in the load. , So that the output voltage of the operating side is taken out. Therefore, the step-down switching regulator 8 and the series regulator 2 are
It can be properly selected and operated according to changes in load.

Further, in the fourth embodiment, the selective operation control of the step-down switching regulator 8 and the series regulator 2 is performed by using the load detection signal S12 in addition to the operation command signal S11. Therefore, as compared with the case where only the operation command signal S11 is used, a more reliable and stable operation can be performed. 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 this power supply device is provided with a charge pump type step-down DC / DC converter 1 and a series regulator 2A, which are different in property from each other. 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 indicates that the drive circuit 1 of the step-down DC / DC converter 1
It is supposed to be supplied to 2.

Here, the load determination signal S21 is a signal corresponding to the magnitude of the load, for example, an "H" level signal when the load is large and an "L" level signal when the load is small. . Step-down DC / DC converter 1
Is configured similarly to 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. However, the difference is that the switch SW1 of FIG. 3 is omitted and the supply of the light load determination signal S1 to the error amplifier 21 of FIG. 3 is omitted.

In the series regulator 2A and the step-down DC / DC converter 1, the output voltage of the constantly operating series regulator 2A is slightly smaller than the output voltage of the step-down DC / DC converter 1 which is operated as necessary. It is configured to be small. For example, step-down D
When the output voltage of the C / DC converter 1 is 3.0 [V], the output voltage of the series regulator 2A is 3.0.
It is configured to be smaller than [V] by about several tens of [mV]. The reason for this will be described later in the operation.

Next, the operation of the fifth embodiment having such a configuration will be described with reference to FIGS. 3 and 12. First, the load determination signal S21 is switched 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 3.0V.

In this case, the series regulator 2A
Is always operating, 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 smaller than 3.0V by several tens of mV. Therefore, the error amplifier 21 shown in FIG.
MOS transistor Q21 for output although operating
Waiting with the power off.

When the load determination signal S21 changes from the "H" level to the "L" level, the step-down DC / DC converter 1 stops its operation, 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. Since the error amplifier 21 is always operating in this way, the time from startup to stabilization is extremely short, and output drop can be prevented.

Next, the case where the load determination signal S21 switches from the "L" level to the "H" level and the operation of the step-down DC / DC converter 1 is started will be described.
As described above, when the step-down DC / DC converter 1 is activated, the series regulator 2A operates until the output voltage Vout exceeds the set value of the series regulator 2A (the value set to decrease from 3.0V to several tens of mV). There is. However, if the step-down DC / DC converter 1 exceeds the set value in the process of raising its output to 3V, the series regulator 2A can automatically turn off the MOS transistor Q21 by the error amplifier 21.

As described above, by compensating the period from the start of the step-down DC / DC converter 1 to the stabilization of the output by the operation of the series regulator 2A, the drop in the output is eliminated. As described above, according to the fifth embodiment, similarly to the first embodiment, the current consumption can be reduced when the load is light, 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. The sixth embodiment of this power supply device is shown in FIG.
As shown in FIG. 3, a step-down switching regulator 8 and a series regulator 2A having different characteristics are provided, and the series regulator 2A is always operated, and the step-down switching regulator 8 receives the load determination signal input to the control terminal 45. The operation is performed according to S21. Therefore, the load determination signal S21 similar to that in the fifth embodiment is supplied to the step-down switching regulator 8.

The step-down switching regulator 8 has the same structure 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 which is always operating is slightly smaller than the output voltage of the step-down switching regulator 8 which is operated as necessary. 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.
It is configured to be reduced from 0 [V] to several tens of [mV]. The reason for this will be described later in the operation.

Next, the operation of the sixth embodiment having such a configuration will be described with reference to FIGS. 3 and 13. First, the load determination signal S21 is switched from the "H" level indicating that the load is a heavy load to the "L" level indicating that the load is a light load, the operation of the step-down switching regulator 8 is stopped, and the series. A case where the operation is switched to 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 0V is output.

In this case, the series regulator 2A
Is always operating, 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 smaller than 3.0V by several tens of mV. Therefore, the error amplifier 21 shown in FIG.
MOS transistor Q21 for output although operating
Waiting with the power off.

When the load determination signal S21 changes from the "H" level to the "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 is always in operation, the time from startup to stabilization is extremely short, and output drop can be prevented.

Next, the case where the load determination signal S21 is switched from the "L" level to the "H" level and the operation of the step-down switching regulator 8 is started will be described below. In this way, when the step-down switching regulator 8 is activated, the series regulator 2A is operating until the output voltage Vout exceeds the set value of the series regulator 2A (the value set to decrease from 3.0V to several tens of mV). However, when the step-down switching regulator 8 exceeds the set value in the process of raising its output to 3V, the series regulator 2A automatically causes the error transistor 21 to set the MOS transistor Q2.
1 can be turned off.

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

Further, 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 and a series regulator 2A, which are different in property from each other, and operate the series regulator 2A at all times. The operation control signal S31 input to the control terminal 53 and the load determination signal S3 from the load detection circuit 52 are used to control the operation of the step-down DC / DC converter 1.
This is done according to 2.

The step-down DC / DC converter 1 has the same structure 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 is configured similarly to the fifth embodiment.

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

Therefore, in the seventh embodiment, the microcomputer controls the operation control signal S3 during the 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 described above, the OR circuit 51 is supplied with a load detection signal S32 output by the load detection circuit 52 detecting the magnitude of the load.
Further, the output signal of the OR circuit 51 is a step-down DC / DC
It is supplied to the drive circuit 12 of the converter 1.

Therefore, in the seventh embodiment, the OR circuit 51 logically operates the operation control signal S31 generated in advance according to the predicted or expected change in the load and the load detection signal S32 from the load detection circuit 52. 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.
And it demonstrates with reference to FIG.

In the seventh embodiment, the series regulator 2A is always in the operating state when the power is turned on. On the other hand, the operation of the step-down DC / DC converter 1 is controlled according to the operation control signal S31 and the load detection signal S32. Therefore, the operation will be described below. In this example, the case where 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. 15A will be described. 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 FIG.
As shown in (B), when commanding a heavy load operation, it is at “H” level, and when commanding a light load operation, “L” level.
It is assumed to be a level. Now, as shown in FIG. 15 (B), when the operation control signal S31 changes from the "L" level to the "H" level at time t1, the output of the OR circuit 51 becomes "L" as shown in FIG. 15 (D). The level changes from "H" level.

Therefore, the drive circuit 12 operates and the step-down DC / DC converter 1 is in the operating state. Therefore, the step-down DC / DC converter 1 can stand by for a heavy load in a stable operation state. After that, FIG.
As shown in (A), when the load is switched from the light load to the heavy load at time t2, the step-down DC /
The DC converter 1 can drive the heavy load.

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

As shown in FIG. 15B, at time t5, the operation control signal S31 changes from "H" level to "L".
When the level changes, the output of the OR circuit 51 is changed to that shown in FIG.
As shown in (D), the level changes from "H" level to "L" level. Therefore, the operation of the drive circuit 12 is stopped, the step-down DC / DC converter 1 is switched to the stopped state, and the output voltage of the series regulator 2A is output to the output terminal 7.
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. Therefore, even if the operation control signal S31 is not normal at time t5,
It can operate according to the load. After that, by repeating such an operation, the step-down DC / D is changed according to the load condition.
The C converter 1 operates and stops.

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

Further, in the seventh embodiment, the step-down 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, as compared with the case where only the operation control signal S31 is used, a more reliable and stable operation can be performed. Next, FIG. 16 shows the eighth embodiment of the power supply device of the present invention.
Will be described with reference to.

As shown in FIG. 16, the eighth embodiment of the power supply device is provided with a step-down switching regulator 8 and a series regulator 2A, which have different properties, and the series regulator 2A is always operated and the step-down type is provided. The operation of the switching regulator 8 is controlled by the operation control signal S31 input to the 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 structure 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. Furthermore, the series regulator 2A and the step-down switching regulator 8 are configured similarly to the sixth embodiment.

Further, in the eighth embodiment, as in the case of the seventh embodiment, the microcomputer generates the operation control signal S31 similar to the above during the control of the load, and the generated operation control signal S31. Is input to the OR circuit 51. In addition to the operation control signal S11 described above, the OR circuit 51 outputs 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 the step-down switching regulator 8
To be supplied to.

Therefore, in the eighth embodiment, the OR circuit 51 logically operates the operation control signal S31 generated in advance according to the predicted or expected change in the load and the load detection signal S32 from the load detection circuit 52. The sum processing is performed, and the operation of the step-down switching regulator 8 is controlled based on the processing result. Next, regarding the operation of the eighth embodiment having such a configuration, FIG. 16 and FIG.
Will be described with reference to.

In the eighth embodiment, the series regulator 2A is always in the operating state when the power is turned on. On the other hand, since the operation of the step-down switching regulator 8 is controlled according to the operation control signal S31 and the load detection signal S32, its operation will be described below.
In this example, a case where 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. 17A will be described. Since this change in load is known in advance,
In response to this, the 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 as shown in FIG.
As shown in (B), when commanding a heavy load operation, it is at “H” level, and when commanding a light load operation, “L” level.
It is assumed to be a level. When the operation control signal S31 changes from the "L" level to the "H" level at time t1 as shown in FIG. 17B, the output of the OR circuit 51 becomes "L" as shown in FIG. 17D. The level changes from "H" level.

Therefore, the step-down switching regulator 8 is put into operation. Therefore, the step-down switching regulator 8 can stand by for a heavy load in a stable operation state. After that, as shown in FIG. 17A, when the load is switched from the light load to the heavy load at time t2, the step-down switching regulator 8 with stable operation can drive the heavy load.

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

As shown in FIG. 17B, at time t5, the operation control signal S31 changes from "H" level to "L".
When the level changes, the output of the OR circuit 51 is changed to that shown in FIG.
As shown in (D), the level changes from "H" level to "L" level. Therefore, the step-down switching regulator 8 switches to the stopped state, and the series regulator 2
The output voltage of A comes to be 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. Therefore, even if the operation control signal S31 is not normal at time t5,
It can operate according to the load. After that, by repeating such an operation, the step-down switching regulator 8 operates or stops depending on the state of the load.

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

Furthermore, 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, as compared with the case where only the operation control signal S31 is used, a more reliable and stable operation can be performed.

[0139]

As described above, according to the present invention,
It is possible to provide a power supply device that can reduce current consumption when the load is light and improve the power conversion efficiency as a whole.

[Brief description of 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 showing a configuration of a second embodiment of a power supply device 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 showing a configuration of a third embodiment of a power supply device of the present invention.

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

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

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

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

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

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

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

FIG. 16 is a block diagram showing the 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]

1 Charge pump type step-down DC / DC converter 2, 2A series regulator 4 input terminals 6 control input terminals 7 output terminals 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

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-301642 (JP, A) JP-A-6-289073 (JP, A) JP-A-2000-11649 (JP, A) US Patent 4194147 (US, A) US Patent 4502152 (US, A) US Patent 4581694 (US, A) US Patent 5083078 (US, A) US Patent 5267136 (US, A) US Patent 6060869 (US, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H02M 3/135 H02M 3/07

Claims (3)

(57) [Claims] 1. A DC / DC converter for receiving a first control signal for switching between driving and stopping and converting a first input voltage into a predetermined output voltage, and a second for controlling switching between driving and stopping. A power supply device comprising a series regulator that receives a control signal and continuously controls an output voltage so that a second input voltage becomes a predetermined output voltage, wherein the DC / DC converter is of a charge pump type. Step-down DC
/ DC converter or a switching regulator, wherein the series regulator includes an input terminal to which the second input voltage is input, an output terminal to which the output voltage is output, a transistor, an error amplifier, and a first resistor. , A second resistor, the input terminal is connected to one end of the transistor, the other end of the transistor is connected to the output terminal, and the first resistor and the second resistor are connected. Is connected to a terminal of a third voltage via a voltage of a connection point between the first resistor and the second resistor, a reference voltage, and an enable signal. Is connected to the gate of the transistor. 2. The power supply device according to claim 1, wherein the enable signal and the second control signal are the same signal, and the second control signal has a level indicating drive, the error The amplifier applies an output corresponding to the comparison between the voltage at the connection point between the first resistor and the second resistor and a reference voltage to the gate of the transistor to control the on resistance of the transistor, A power supply device characterized by outputting a voltage. 3. The power supply device according to claim 1, further comprising a switch element between the second resistor and the terminal for the third voltage.