JP2002252967A - Stabilized power supply circuit and device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stabilized power supply circuit capable of securing suffi cient life of battery in supplying power to a load at the light source. SOLUTION: In a stabilized power supply circuit 1, an output voltage setting circuit 5 inputs a setting signal b in response to an input control signal a to a variable dc voltage source 4, and a reference voltage Vref 1 input to a comparator 3 is chosen to be a voltage corresponding to the voltage value of an output voltage Vo to be set. The comparator 3 compares a feedback voltage Vfb 1 with the reference voltage Vref 1 and inputs a signal c to a control portion 2, and the control portion 2 stabilizes the target output voltage Vo by letting S1, S2, S3, S4 and a capacitor C1 perform switched capacitor operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilized power supply circuit for stabilizing and outputting an input voltage, and a device having the stabilized power supply circuit.

[0002]

2. Description of the Related Art White LEDs are used for color liquid crystal backlights of portable equipment such as portable telephones and portable terminals. Operating voltage V _F of the white LED is as high as approximately 4V, if the well is to be used a lithium ion battery used in a portable device as power supply of the color liquid crystal backlight, with a voltage of 3.6V drives the white LED direct emission I can't let that happen. Therefore, the voltage of the lithium ion battery is increased.

FIG. 10 shows a configuration of a switched capacitor type stabilized power supply circuit 101 used as a booster circuit. The stabilized power supply circuit 101 includes an integrated portion 101a, external capacitors C101, C102, C103 and voltage dividing resistors R101, R102. The integrated portion 101a has an output terminal T10 for outputting the output voltage Vo '.
1. An input terminal T102 to which an input voltage Vin is input from a power source such as a battery, and a feedback terminal T of an output voltage Vo ′.
103, a GND terminal T104, and a capacitor connection terminal T to which the low potential side electrode C- 'of the capacitor C101 is connected.
105 and the electrode C on the high potential side of the capacitor C101
A capacitor connection terminal T106 to which + 'is connected is provided.

In this stabilized power supply circuit 101, a switch S
A switched capacitor unit is constituted by 101, S102, S103, S104 and the capacitor C101. When the switches S101 and S103 are off and the switches S102 and S104 are on,
The input voltage Vin is applied to the input terminal T102 via the capacitor 102, and the capacitor C101 is charged. Next, the switches S101 and S103 are turned on and the switch S
102 and S104 are turned off, and the capacitor C1
01 is increased by the potential of the input terminal T102. The voltage boosted by such an operation is output as the output voltage Vo ′ via the capacitor C103.

[0005] The output voltage Vo 'is divided by the voltage dividing resistors R101 and R1.
02, the voltage Vfb101 at the connection point between the voltage dividing resistors R101 and R102 is input to the comparator 112. In the comparator 112, the voltage Vfb101 is compared with the reference voltage Vref101. When the voltage Vfb101 reaches the reference voltage Vref101, the comparator 112 outputs a signal to the control unit 111 to stop the boosting operation. The comparator 112 is a comparator with a hysteresis function. When the operation of the switched capacitor unit stops and the output voltage Vo ′ decreases, that is, when the voltage Vfb101 decreases, the control unit 111
To start the boosting operation. The above-described switched capacitor operation is repeated, and the output voltage Vo ′ is stabilized.

[0006] In addition to the above configuration, FIG.
As shown in FIG. 7, there is also a stabilized power supply circuit 102 configured to insert a series regulator after the capacitor C103 to suppress noise of the output voltage Vo2 '. The integrated portion 102a has a capacitor connection terminal T107 for connecting the capacitor C103. In this configuration, the capacitor C103 is operated by the switched capacitor operation.
Is output from the output transistor T1.
When a predetermined amount of voltage drops at r101, the output terminal T10
1 is output as an output voltage Vo2 'via the capacitor C104. The output voltage Vo2 'is a voltage dividing resistor R103.R
The voltage Vfb102 detected at the connection point between the voltage dividing resistor R103 and the voltage dividing resistor R104 is input to the comparator 113 and compared with the reference voltage Vref102. The comparator 113 outputs a voltage corresponding to the difference between the voltage Vfb102 and the reference voltage Vref102 to the output transistor T.
r101 to adjust the impedance of the output transistor Tr101. By this impedance adjustment, the voltage drop in the output transistor Tr101 is adjusted, and the output voltage Vo2 'is a particularly stabilized voltage in which noise is suppressed.

[0007]

However, from a conventional stabilized power supply circuit that performs boosting, such as the above-mentioned stabilized power supply circuits 101 and 102, to a load as a light source such as a white LED, etc. When power is supplied, there is a problem that a battery for applying the input voltage Vin to the stabilized power supply circuit is greatly consumed, and a sufficient life of the battery cannot be secured. This problem is particularly significant in portable devices using a white LED as a light source.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a stabilized power supply circuit capable of securing a sufficient life of a battery when power is supplied to a load as a light source. Is to provide.

[0009]

According to the present invention, there is provided a stabilized power supply circuit for stabilizing an input voltage and outputting an output voltage generated by stabilizing the input voltage.
Output voltage setting means for setting the output voltage to a voltage value according to a control signal to be input, wherein the output voltage setting means sets the voltage value to a value supplied to a load to which the output voltage is applied. At least, the power supply is set to a value that is a standard supply power and a value that is greater than zero and less than the standard supply power.

According to the above invention, when the stabilized power supply circuit supplies power to the load, the output voltage setting means sets the output voltage applied to the load to a voltage value according to the input control signal. . Since this voltage value can take at least a value at which the power supplied to the load is the standard power and a value within a range of more than zero and less than the standard power, the output voltage setting means When the output voltage is set to a voltage value such that the power supplied to the load is within the above range, the output voltage from the power supply that applies the input voltage to the stabilized power supply circuit is compared with the case where the standard power supply is always performed to the load. The power supply decreases.

Therefore, when a light source such as a white LED is used as the load, standard power is supplied to the load only when the maximum light emission intensity is required, and otherwise, the output voltage setting means supplies the load with the output voltage setting means. It is possible to set the output voltage so that the supply power of the light-emitting device is reduced and to reduce the light emission intensity. If a method of use that reduces the power supplied to the load is executed, the life of the battery can be extended when a battery is used as a power supply that applies an input voltage to the stabilized power supply circuit. In addition, the life can be sufficiently extended depending on the voltage value set by the output voltage setting means and the usage period of the voltage value.

As described above, it is possible to provide a boosted stabilized power supply circuit capable of securing a sufficient battery life when supplying power to a load as a light source.

Further, in order to solve the above problem, the stabilized power supply circuit according to the present invention is characterized in that the voltage value is a discrete value corresponding to the level of the control signal.

According to the present invention, since the voltage value is a discrete value corresponding to the level of the control signal, it is easy to control the output voltage of the stabilized power supply circuit to the voltage value. Can be kept to a practical number. Further, when the generation of the control signal input to the output voltage setting means is left to the selection of the operator, the selection operation is facilitated.

Further, in order to solve the above-mentioned problems, in the stabilized power supply circuit according to the present invention, a plurality of the control signals are input to the output voltage changing means, and the voltage value is a combination of a plurality of levels of the control signals. It is characterized by the fact that

According to the present invention, since the voltage value is determined by a combination of the levels of a plurality of control signals, when the level is represented by "High" and "Low", four control signals are used. As in the case of setting instructions for the above-mentioned voltage values, setting instructions for a large number of the voltage values can be issued with a small number of control signals.

Further, in order to solve the above-mentioned problem, the stabilized power supply circuit according to the present invention is characterized in that the voltage value includes a value at which the supply power becomes zero.

According to the above invention, it is possible to prevent the stabilized power supply circuit from supplying power to the load by the output voltage setting means. For example, when the load is a light source such as a white LED, the output voltage can be reduced to a value at which the operating current does not flow, and the light can be turned off. As described above, by stopping the operation of the load when the driving is unnecessary, the power consumption can be further reduced, and the life of the battery can be further extended.

Further, in order to solve the above-mentioned problems, the stabilized power supply circuit of the present invention controls the operation of stabilizing the output voltage by comparing the detected value of the output voltage with a reference voltage and controls the voltage dividing resistor. A stabilizing operation means for generating a plurality of reference voltages including a voltage, and wherein the output voltage setting means includes a reference voltage corresponding to the voltage value as the reference voltage used by the stabilizing operation means for controlling the stabilizing operation. The output voltage is set to the voltage value by selecting a pressure.

According to the above invention, the output voltage setting means selects the divided voltage of the voltage dividing resistor corresponding to the voltage value as the reference voltage used by the stabilizing operation means for controlling the stabilizing operation of the output voltage. Thereby, the output voltage of the stabilized power supply circuit is set to the above voltage value. Since the setting of the voltage value is performed by using the divided voltage of the voltage dividing resistor having a small number of parts, the configuration for the setting can be simplified.

Further, in order to solve the above-mentioned problem, the stabilized power supply circuit of the present invention is characterized in that the stabilized power supply circuit is provided with a series regulator for generating the output voltage.

According to the above invention, since the output voltage of the stabilized power supply circuit is generated by the series regulator,
The output voltage noise can be sufficiently reduced. In particular, when a light source such as a white LED is used for the load, the power supplied to the load is stabilized, so that a stable light emitting state can be obtained.

Further, the device of the present invention is characterized in that it is packaged with an integrated part of any one of the stabilized power supply circuits.

According to the above-described invention, since the package is provided with the integrated portion of the stabilized power supply circuit,
The mounting area is small when mounted on equipment as a component,
The size of the device can be reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment of a stabilized power supply circuit according to the present invention will be described below with reference to FIG.

FIG. 1 shows a configuration of a stabilized power supply circuit 1 according to the present embodiment. The stabilized power supply circuit 1 is a switched-capacitor type power supply circuit that performs a boosting operation to supply power to a load such as a light source such as a backlight for display of a portable device such as a mobile phone or a portable terminal. is there.
The stabilized power supply circuit 1 includes an integrated portion 1a, capacitors C1, C2, and C3 and a voltage dividing resistor R connected to the outside of the integrated portion 1a.
1 · R2.

The integrated portion 1a includes an output terminal T1 for outputting an output voltage Vo applied to a load such as a white LED, and an input terminal T for receiving an input voltage Vin from a power source such as a battery.
2. Control for inputting a feedback terminal T3 to which a detection value of the output voltage Vo is input, a GND terminal T4, capacitor connection terminals T5 and T7 to which the capacitor C1 is connected, and a control signal to an output voltage setting circuit 5 to be described later. Terminal T6
It has.

Outside the integrated portion 1a, the capacitor C
1, the low potential side electrode C− is connected to the capacitor connection terminal T5,
The electrode C + on the high potential side of the capacitor C1 is connected to the capacitor connection terminal T7. The capacitor C2 is connected between the input terminal T2 and the GND line. The capacitor C3 is connected between the output terminal T1 and the GND line. The voltage dividing resistors R1 and R2 are connected to the output terminal T
1 and the GND line, the voltage dividing resistor R1 is connected in series with the output terminal T1 side. The connection point between the voltage dividing resistors R1 and R2 is connected to the feedback terminal T3. A voltage division of the output voltage Vo appears at a connection point between the voltage dividing resistors R1 and R2, and this voltage is input to the feedback terminal T3 as a feedback voltage Vfb1. G
The ND terminal T4 is connected to a GND line outside the integrated portion 1a. The control terminal T6 will be described later.

In the integrated portion 1a, a switch S1 and a switch S2 which conduct and cut off the path connecting the output terminal T1 and the input terminal T2 are connected to the switch S
1 are connected in series with the output terminal T1 side. Also, a switch S3 and a switch S4 for conducting and blocking this path are connected to a path connecting the input terminal T2 and the GND line inside the integrated portion 1a, and the switch S3 is connected to the input terminal T.
They are connected in series as two sides. Further switch S1
Is connected to the switch S2 by a capacitor connection terminal T7.
The connection point between the switches S3 and S4 is connected to a capacitor connection terminal T5. The switches S1, S2, S3, S4 and the capacitor C1 constitute a switched capacitor unit.

The switches S1, S2, S3, S
A control unit 2 for controlling the ON state (conduction state) and the OFF state (cutoff state) of the control unit 4 is provided. The control unit 2 simultaneously turns on and off the switches S1 and S3, and simultaneously turns on or off the switches S2 and S4.
Set to F state.

Further, the control unit 2 has a comparator 3 for inputting a signal c for determining the timing of turning on the set of switches S1 and S3 and the set of switches S2 and S4 and the timing of turning off the set. Is provided. The non-inverting input terminal of the comparator 3 is connected to a feedback terminal T3, and the inverting input terminal is connected to a variable DC voltage source 4 provided to input a reference voltage Vref1 thereto. The comparator 3 outputs a feedback voltage Vfb input from the voltage dividing resistors R1 and R2 to the non-inverting input terminal via the feedback terminal T3.
1 is compared with the reference voltage Vref 1 input to the inverting input terminal, and the feedback voltage Vfb 1 is compared with the reference voltage Vref 1
While the voltage is lower, a signal c for instructing the switches S1 and S3 to be in the ON state and the switches S2 and S4 to be in the OFF state is output to the control unit 2. When the feedback voltage Vfb1 reaches the reference voltage Vref1, the switches S1 and S3 are activated. OF
The control unit 2 outputs a signal c for giving an instruction to turn on the switches S2 and S4 in the F state. The comparator 3 has a hysteresis function. When the feedback voltage Vfb1 becomes lower than the reference voltage Vref1,
The switches S1 and S3 are turned on again, and the switches S2 and S
A signal c for giving an instruction to turn off the signal 4 is output to the control unit 2.

Further, there is provided an output voltage setting circuit 5 for inputting a setting signal b for determining the magnitude of the reference voltage Vref1 of the variable DC voltage source 4 to the variable DC voltage source 4.
The output voltage setting circuit 5 outputs a setting signal b corresponding to a control signal a input from the outside of the integrated part 1a such as a microcomputer or a chip set via a control terminal T6. The control signal a may be in the form of a digital signal having different levels such as “High” and “Low”,
It may be in the form of an analog signal. For example, when the control signal a is the digital signal, the output voltage setting circuit 5 outputs a setting signal b having different contents in accordance with the level of the control signal a to determine the magnitude of the reference voltage Vref1. In this case, the reference voltage Vref 1 has a discrete value corresponding to the type of the setting signal b, but in other cases, the reference voltage Vref 1 which is continuously variable by the setting signal b.
It may be 1. The operation of the switched capacitor is controlled by the reference voltage Vref1 determined in this way, and the voltage value of the output voltage Vo of the stabilized power supply circuit 1 is determined.

In this embodiment, the control signal a is "H"
When the output voltage Vo is at the "high" level or the "Low" level, the output voltage setting circuit 5 sets the output voltage Vo to a standard voltage value Vo such that the power supplied to the load becomes the standard power.
The setting signal b to be (1) is input to the variable DC voltage source 4.
The standard voltage value Vo (1) corresponds to an output voltage that has been set to a constant value in a conventional stabilized power supply circuit. When the level of the control signal a is opposite to the above, the output voltage setting circuit 5 sets the output voltage Vo such that the power supplied to the load is larger than zero and smaller than the standard power supply. Setting signal b to be a voltage value Vo (2) lower than the voltage value of
Is input to the variable DC voltage source 4. As described above, the output voltage setting circuit 5 sets “the output voltage to a voltage value corresponding to the input control signal, and sets the voltage value to at least the standard power supplied to the load to which the output voltage is applied. And a value within a range of greater than zero and smaller than the standard defined supply power. " It is also possible to increase the number of levels of the control signal a from the above example, increase the type of the voltage value of the output voltage Vo compared to the above example, and to set the voltage value as a discrete value in a stepwise manner. is there.

The configuration of the integrated portion 1a has been described above.

Next, the operation of the stabilized power supply circuit 1 having the above configuration will be described. First, when the input voltage Vin starts to be input to the input terminal T2 via the capacitor C2,
Switches S1 and S3 are turned off by control unit 2.
State, the switches S2 and S4 are turned on. Thereby, the capacitor C1 is charged. Next, the switches S2 and S4 are turned off by the control unit 2,
The switches S1 and S3 are turned on, and the capacitor C1
The potential of the electrode C− of the capacitor C1 rises from the GND potential to the potential of the input terminal T2, and the potential of the electrode C + of the capacitor C1 changes to the potential of the electrode C−.
, That is, the potential of the input terminal T2. Then, the potential of the electrode C + is output from the output terminal T1 as the output voltage Vo, the capacitor C3 is charged, and the output voltage Vo is applied to the load.

The output voltage Vo is detected by the voltage-dividing resistors R1 and R2, and the feedback voltage Vfb1 at the connection point between the voltage-dividing resistors R1 and R2 is used as a detection value as a detection value through the non-inverting input of the comparator 3 via the feedback terminal T3. Input to the terminal. Comparator 3 has feedback voltage Vfb
1 and the reference voltage Vref 1 of the variable DC voltage source 4 are compared. At this time, the control signal a input to the output voltage setting circuit 5 via the control terminal T6 causes the output voltage setting circuit 5 to set the setting signal b for setting the output voltage Vo to the above-described standard voltage value Vo (1). If it is output, the reference voltage Vref 1 is a voltage corresponding to the voltage value Vo (1).

The comparator 3 has a feedback voltage Vfb.
And outputs a signal c for giving an instruction to the control unit 2 to keep the switches S1 and S3 on and the switches S2 and S4 off until the reference voltage Vref1 reaches the reference voltage Vref1.
The control unit 2 sets the switches S1, S2, S3, and S4 in the above-described state. When the feedback voltage Vfb1 reaches the reference voltage Vref1, the comparator 3 sends the control unit 2 the switches S1 and S3 to the OFF state and the switch S2
Output a signal c for giving an instruction to turn on S4;
The control unit 2 sets the switches S1, S2, S3, and S4 in the above-described state. When the feedback voltage Vfb1 becomes lower than the reference voltage Vref1, switches S1 and S3 are turned on again, and switches S2 and S4 are turned on again.
A signal c for giving an instruction to set the state to the FF state is output. By repeating such a switched capacitor operation,
The output voltage Vo is stabilized at a standard voltage value Vo (1).

For example, when a white LED is connected as a load, standard power is supplied while the output voltage Vo is set to the voltage value Vo (1), and the white LED emits light at a standard intensity. If this is used as, for example, a backlight for display of a device, it is effective to emit light at a standard intensity or lower, or to perform some kind of transmission to an operator of the device by changing the light emission intensity. A situation also arises. In accordance with such a situation, the output voltage setting circuit 5 causes the output voltage Vo to be lower than the standard voltage value Vo (1) by the control signal a input to the output voltage setting circuit 5 via the control terminal T6. Setting signal b to be set to voltage value Vo (2)
Is output. As a result, the reference voltage Vref1 of the variable DC voltage source 4 becomes a voltage corresponding to the voltage value Vo (2), and the output voltage Vo is stabilized to the voltage value Vo (2) by the same operation of the comparator 3 as described above. You. Then, power smaller than the standard power is supplied to the load, and in the case of a white LED, the current decreases and the light emission intensity decreases. The generation of the control signal a and the input instruction may be performed automatically or manually by an operator. Of course, both automatic and manual operations may be configured.

As described above, according to the stabilized power supply circuit 1 of the present embodiment, when power is supplied to the load, the output voltage setting circuit 5 controls the output voltage Vo applied to the load by the input control. The voltage value is set according to the signal a. Since this voltage value is in a range where at least the power supplied to the load is larger than zero and smaller than the standard power supply as in the above-described voltage value Vo (2), the output voltage Vo is set by the output voltage setting circuit 5. When the voltage value is set so that the power supplied to the load is within the above range, the input voltage V is supplied to the stabilized power supply circuit 1 as compared with the case where the standard power is always supplied to the load.
The power supplied from the power supply applying in decreases.

Therefore, when a light source such as a white LED is used as a load, standard power is supplied to the load only when the maximum luminous intensity is required. It is possible to set the output voltage Vo so as to reduce the power supplied to the power supply and reduce the light emission intensity. Then, if a usage method that reduces the power supplied to the load is executed, when a battery such as a lithium ion battery is used as a power supply for applying the input voltage Vin to the stabilized power supply circuit 1, the life of the battery is extended. be able to. Further, the life can be made sufficiently long depending on the voltage value set by the output voltage setting circuit 5 and the usage period of the voltage value.

As described above, it is possible to provide a stabilized power supply circuit capable of securing a sufficient life of a battery when supplying power to a load as a light source.

Further, the voltage values Vo (1) and Vo (2) of the output voltage Vo set by the output voltage setting circuit 5 or more types of voltage values are discrete values corresponding to the level of the control signal a. This makes it easy to control the output voltage Vo of the stabilized power supply circuit 1 to the above-mentioned voltage value. Furthermore, if the voltage value of the output voltage Vo can be set by a continuous change, if the settable voltage value is too large or it becomes difficult to set the target voltage value, the above-mentioned voltage value is discretely set. In this case, the number of types of voltage values can be kept at a practical number. Further, when the generation of the control signal a input to the output voltage setting circuit 5 is left to the selection of a button or switch by the operator, the selection operation is facilitated.

In this embodiment, the stabilized power supply circuit of the switched capacitor type has been described. However, the stabilized power supply circuit is not limited to this. For example, another boosted type stabilized power supply circuit such as a boosted chopper type Alternatively, a stabilized power supply circuit without boosting may be used, and any stabilized power supply circuit capable of stabilizing a voltage may be used. The same applies to the following embodiments.

[Second Embodiment] Another embodiment of the stabilized power supply circuit of the present invention will be described below with reference to FIGS. Components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 2 shows a configuration of a stabilized power supply circuit 11 which is a first example of the stabilized power supply circuit according to the present embodiment.
The stabilized power supply circuit 11 has an integrated portion 11a, and capacitors C1, C2, C3 and voltage dividing resistors R1, R2 connected to the outside thereof. The integrated portion 11a replaces the variable DC voltage source 4 with the variable DC voltage source 14 and the output voltage setting circuit 5 with the output voltage setting circuit 15 in the integrated portion 1a of the stabilized power supply circuit 1 described in the first embodiment. Connected to the output voltage setting circuit 15 and the integrated portion 11
This is a configuration provided with a control terminal T8 to which another control signal is input from a microcomputer or a chip set or the like outside of FIG.

The variable DC voltage source 14 inputs the reference voltage Vref 2 to the comparator 3, and the reference voltage Vref 2 is equal to the reference voltage Vref 2a, Vref 2b, Vref 2c, Vref 2d.
It is designed to take on three different levels. The reference voltage Vref 2a is a voltage at which the output voltage Vo becomes the standard voltage value Vo (1) described in the first embodiment.
f 2b, Vref 2c, and Vref 2d are voltage values Vo obtained by further dividing the voltage value Vo (2) whose output voltage Vo is lower than the standard voltage value Vo (1) described in the first embodiment into three different levels. (2-1) · Vo (2-2) · Vo (2-3).
Here, Vo (2-1)> Vo (2-2)> Vo (2-3).

The output voltage setting circuit 15 outputs a signal from the variable DC voltage source 14 to the comparator in accordance with a combination of the control signal a1 input via the control terminal T6 and the control signal a2 input via the control terminal T8. A setting signal b for determining the level of the reference voltage Vref 2 input to the reference 3 is input to the variable DC voltage source 14. Here, the two control signals a1
A2 becomes one of the "High" level and the "Low" level, and the setting signals b corresponding to each of the four combinations of these levels cause the reference voltage Vref 2a.Vref as shown in Table 1. 2b ・ Vref 2c
-Vref 2d shall be determined.

[0048]

[Table 1]

In the table, "H" indicates a "High" level, and "L" indicates a "Low" level. According to such a multi-stage setting of the output voltage Vo, the stabilized power supply circuit 1
For example, when power is supplied to a display backlight such as a white LED provided in a mobile phone, a voltage value Vo (1) is set in an initial state of the call to maximize the brightness of the display, and a call is started. One minute after setting, set the voltage value to Vo (2-1) and slightly lower the brightness of the display. For example, voltage value Vo (2-1) → voltage value Vo (2-2) → voltage value It is possible to reduce the power consumption of the backlight by making it gradually darker to Vo (2-3). Further, a voltage value at which the power supply to the load becomes zero is provided instead of the voltage value Vo (2-3), and the voltage value is finally set to this voltage value and the output of the stabilized power supply circuit 11 is set to zero (cut off). ) Or may be set to another voltage value such as the voltage value Vo (1) again after a predetermined time or at a predetermined timing, and the switching sequence between the output voltages Vo is arbitrary. Of course, a configuration in which the operator switches the voltage value may be employed. Further, the number of control signals may be further increased to increase the type of the voltage value of the output voltage Vo.

As described above, according to the stabilized power supply circuit 11 of the present embodiment, since the voltage value of the output voltage Vo is determined by the combination of the levels of the plurality of control signals, the levels are set to "High" and "High". In the case of being represented by “Low”, setting instructions for a large number of the voltage values can be performed with a small number of control signals, such as a case where two setting signals can be used to perform the setting instructions for the four voltage values. .

Next, FIG. 3 shows a configuration of a stabilized power supply circuit 21 which is a second example of the stabilized power supply circuit according to the present embodiment. The stabilized power supply circuit 21 includes an integrated portion 21a, and capacitors C1, C2, and C3 and voltage dividing resistors R1 and R2 that are connected to the outside of the integrated portion 21a. The integrated portion 21a is an integrated portion 1 of the stabilized power supply circuit 1 described in the first embodiment.
The variable DC voltage source 4 in FIG.
The output voltage setting circuit 5 is replaced with an output voltage setting circuit 25, and the stabilized power supply circuit 11 according to the present embodiment is
This is a configuration provided with a control terminal T8 in the same manner as described above.

The variable DC voltage source 24 is configured to input the reference voltage Vref 2 to the comparator 3 so that the reference voltage Vref 2 can have three different levels of the reference voltages Vref 2a, Vref 2b, and Vref 2c. The output voltage setting circuit 25 outputs the setting signal b for determining the level of the reference voltage Vref 2 input from the variable DC voltage source 24 to the comparator 3 according to the combination of the control signal a1 and the control signal a2. 24, or a power cutoff signal d to the control unit 2 so that the power supplied to the load becomes zero (output is OFF). Here, the control signals a1
a2 becomes one of a “High” level and a “Low” level, respectively. Of four combinations of these levels, a setting signal b corresponding to each of three combinations and a power cutoff signal corresponding to the remaining combinations d, the reference voltage Vref 2a · Vref 2b · Vref 2 as shown in Table 2.
c and OFF of the output are determined.

[0053]

[Table 2]

In the table, "H" indicates a "High" level, and "L" indicates a "Low" level. When the power cutoff signal d is input, the control unit 2 turns off the switches S1 and S3 most simply in order to turn off the output.
State. At this time, the reference voltage Vref 2a · Vref 2
None of b · Vref 2c is input to the comparator 3.

As described above, according to the stabilized power supply circuit 21,
The output voltage setting circuit 25 can prevent power supply to the load. By stopping the operation of the load when driving is unnecessary, power consumption can be further reduced, and the life of the battery can be further extended. The same can be said for the case where a voltage value at which power supply to a load is zero is provided in place of the voltage value Vo (2-3) in the stabilized power supply circuit 11 described above.

As an example, FIG. 4 shows a white LE as a load.
The configuration of a stabilized power supply circuit 31 in which an LED 32 such as D is connected and the stabilized power supply circuit 21 is slightly modified is shown. The stabilized power supply circuit 31 is a voltage dividing resistor R in the stabilized power supply circuit 21.
1 · R2 is replaced by a series circuit of an LED 32 and a resistor R3. The LED 32 is connected to the output terminal T1 side, and also functions as a voltage dividing circuit for detecting the output voltage Vo by the LED 32 and the resistor R3. A connection point between the LED 32 and the resistor R3 is connected to a feedback terminal T3, and a feedback voltage V corresponding to the output voltage Vo is supplied from the connection point.
fb2 is input to the feedback terminal T3 as a detection value of the output voltage Vo.

In the stabilized power supply circuit 31 having the above configuration,
When the output is set to OFF by the output voltage setting circuit 25, the control unit 2 turns off the switches S1 and S3.
State. Thereafter, a current flows from the capacitor C3 to the LED 32. When the current gradually decreases and the charging voltage of the capacitor C3 decreases to a predetermined value, no current flows to the LED 32 and the LED 32 is turned off.

[Embodiment 3] Still another embodiment of the stabilized power supply circuit of the present invention will be described below with reference to FIG. The first embodiment
Components having the same functions as the components described in and 2 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 5 shows a configuration of a stabilized power supply circuit 41 according to the present embodiment. The stabilized power supply circuit 41 includes an integrated portion 41a and externally connected capacitors C1 and C2.
C3 and voltage dividing resistors R1 and R2. The integrated portion 41a is the stabilized power supply circuit 2 described in the second embodiment.
In this configuration, the variable DC voltage source 24 in the integrated portion 21a is replaced with a variable DC voltage source 44.

The variable DC voltage source 44 is a DC constant voltage source 44a.
And voltage dividing resistors R4, R5, R6. The DC constant voltage source 44a generates the reference voltage Vref 2a, and is configured to be able to apply and cut off the reference voltage Vref 2a to the inverting input terminal of the comparator 3. The voltage dividing resistors R4, R5, and R6 are connected in series in this order between one end of the DC constant voltage source 44a whose potential is the reference voltage Vref 2a and the GND line so that the voltage dividing resistor R4 is on the one end side. It is connected to become. The connection point between the voltage dividing resistor R4 and the voltage dividing resistor R5 is connected to the reference voltage Vref 2b, which is a voltage dividing of the reference voltage Vref 2a, by the voltage dividing resistor R5 and the voltage dividing resistor R6.
And a reference point Vref 2c which is a divided voltage of the reference voltage Vref 2a.
Each of the refs 2c is configured to be able to apply and cut off to the inverting input terminal of the comparator 3.

The output voltage setting circuit 25 supplies the control signal a 1.
The reference voltage Vref 2a.
The setting signal b indicates which of Vref 2b and Vref 2c should be applied to the inverting input terminal of the comparator 3. The reference voltage Vref 2a · Vre determined thereby
Based on one of f 2b and Vref 2c, the output voltage Vo is stabilized by the method described above.

As described above, the control unit 2, the comparator 3, and the variable DC voltage source 44 control the output voltage stabilizing operation by comparing the detected value of the output voltage with the reference voltage, and perform the operation of dividing the voltage dividing resistor. And a stabilizing operation means for generating the plurality of reference voltages including the voltage. The number of reference voltages is equal to the reference voltage Vref 2a · Vre as in the present embodiment.
The number is not limited to three of f2b and Vref2c, and is provided by the number corresponding to the voltage value of the output voltage Vo to be set. The output voltage setting circuit 25 supplies the variable DC voltage source 44 with reference voltages Vref 2a, Vref 2b, and reference voltages V (2-1), Vo (2-2), and Vo (2-3) corresponding to the output voltage Vo. Vref 2c to comparator 3
To set the output voltage Vo of the stabilized power supply circuit 41 to the above voltage value. That is, the output voltage setting circuit 25 selects the divided voltage of the voltage dividing resistors R4, R5, and R6 corresponding to the voltage value as the reference voltage Vref2 used by the stabilizing operation means for controlling the stabilizing operation of the output voltage Vo. Thus, the output voltage Vo of the stabilized power supply circuit 41 is set to the above voltage value. Since the setting to the voltage value is performed using the voltage divided by the voltage dividing resistors having a small number of components, such as the voltage dividing resistors R4, R5, and R6, the configuration for the setting can be simplified.

[Fourth Embodiment] Still another embodiment of the stabilized power supply circuit of the present invention will be described below with reference to FIGS. Note that components having the same functions as those described in the first to third embodiments are given the same reference numerals, and descriptions thereof are omitted.

FIG. 6 shows a configuration of a stabilized power supply circuit 51 which is a first example of the stabilized power supply circuit according to the present embodiment.
The stabilized power supply circuit 51 includes an integrated portion 51a, capacitors C1, C2, C4, C5 connected to the outside thereof, and voltage dividing resistors R11, R12.

The integrated portion 51a includes an output terminal T1, an input terminal T2, a feedback terminal T3, a GND terminal T4,
Capacitor connection terminals T5 and T7, control terminals T6 and T8,
And a capacitor connection terminal T9 to which the capacitor C4 is connected.

Outside the integrated portion 51a, the capacitor C4 is connected between the capacitor connection terminal T9 and the GND line. The capacitor C5 is connected between the output terminal T1 and the GND line. Voltage dividing resistor R11 and voltage dividing resistor R
12 is a voltage dividing resistor R between the output terminal T1 and the GND line.
11 are connected in series with the output terminal T1 side. The connection point between the voltage dividing resistors R11 and R12 is connected to the feedback terminal T3. Voltage dividing resistor R11
A voltage division as a detection value of the output voltage Vo2 appears at a connection point between the feedback voltage Vfb and the voltage dividing resistor R12.
3 is input to the feedback terminal T3.

The integrated portion 51a has a configuration in which a series regulator for generating the output voltage Vo 2 is connected to the subsequent stage of the switched capacitor circuit. In the integrated portion 51a, a path connecting the output terminal T1 and the input terminal T2 includes switches S1 and S2 connected in series with each other, which constitute a part of the switched capacitor circuit, and further includes a switch S1 and an output terminal T1. MOS that constitutes a part of the series regulator so that the current path is in series between
An output transistor Tr1 such as an FET is provided. The output transistor Tr1 has an impedance control terminal for receiving an input of a signal e for controlling the impedance of the current path. Impedance control terminal is MOS
In the case of FET, it is a gate terminal.

In the switched capacitor circuit, FIG.
5, switches S3 and S4, a control unit 2, and a comparator 3 are provided. Also,
A connection point between the switch S1 and the output transistor Tr1 is connected to a capacitor connection terminal T9. Between the connection point and the GND line inside the integrated portion 51a, voltage dividing resistors R21 and R22 are connected in series with the voltage dividing resistor R21 as the connection point side. Voltage dividing resistor R21 and voltage dividing resistor R
At the connection point with the switch 22, a divided voltage of the voltage Vo 1 at the connection point between the switch S 1 and the output transistor Tr 1 appears, and this is input to the non-inverting input terminal of the comparator 3 as a feedback voltage Vfb 4. Further, a reference voltage source 52 for generating the reference voltage Vref 52 is provided, and this reference voltage Vref 52 is input to the inverting input terminal of the comparator 3.

On the side of the series regulator, a comparator 53 is provided, and a non-inverting input terminal is connected to the feedback terminal T3. Also, the reference voltage Vref
A variable DC voltage source 54 for generating the reference voltage Vref 3 is provided, and the reference voltage Vref 3 is connected to the inverting input terminal of the comparator 53. The comparator 53 compares the feedback voltage Vfb3 input to the non-inverting input terminal via the feedback terminal T3 with the reference voltage Vref3 input to the inverting input terminal, and outputs a signal e corresponding to the difference between the two to the output transistor Tr1. , And controls the impedance of the current path of the output transistor Tr1.

The series regulator drops the voltage Vo1 which is the output voltage of the switched capacitor circuit by the impedance of the output transistor Tr1, and outputs it from the output terminal T1 as the output voltage Vo2. The output voltage Vo2 is detected by the voltage dividing resistors R11 and R12 and input to the comparator 53 as the feedback voltage Vfb3. The comparator 53 compares the feedback voltage Vfb3 with the reference voltage Vref3, outputs a signal e so that the feedback voltage Vfb3 matches the reference voltage Vref3, and adjusts the impedance of the output transistor Tr1 to reduce the output voltage Vo2. Stabilize. Since the output voltage Vo 2 is stabilized by the series regulator, the noise of the output voltage Vo 2 is sufficiently reduced, and the output voltage Vo 2 becomes a particularly stable voltage.

Here, the variable DC voltage source 54 supplies the reference voltage V
The reference voltage Vref 3a · Vref 3b · Vref is used as ref3.
It is configured to take four different levels of 3c · Vref 3d. The reference voltage Vref 3a is equal to the output voltage Vo.
Reference numeral 2 denotes a voltage having the standard voltage value Vo (1) described in the first embodiment, and a reference voltage Vref 3b, Vref 3c, Vref3.
d is a voltage value Vo (2-1) .Vo (2-2) .V which is obtained by further dividing the voltage value Vo (2) whose output voltage Vo2 is lower than the standard voltage value Vo (1) into three different levels. Vo (2-3).

Further, the integrated portion 51a includes an output voltage setting circuit 55 similar to the output voltage setting circuit 15 described in the second embodiment. The output voltage setting circuit 55 inputs an input from the variable DC voltage source 54 to the comparator 53 in accordance with a combination of the control signal a1 input via the control terminal T6 and the control signal a2 input via the control terminal T8. The setting signal b for determining the level of the reference voltage Vref 3 is input to the variable DC voltage source 54. Levels of control signals a1, a2 and reference voltages Vref 3a, Vref 3b, Vref 3c
Table 3 shows the correspondence with Vref 3d.

[0073]

[Table 3]

In the same table, “H” indicates “High” level, and “L” indicates “Low” level.

As described above, according to the stabilized power supply circuit 51 of the present embodiment, the voltage after boosting by the switched capacitor circuit is stabilized by the series regulator to the output voltage Vo 2, so that the noise of the output voltage Vo 2 Can be sufficiently reduced. In particular, when a light source such as a white LED is used for the load, the power supplied to the load is stabilized, so that a stable light emitting state can be obtained.

Next, FIG. 7 shows a configuration of a stabilized power supply circuit 61 which is a second example of the stabilized power supply circuit according to the present embodiment. The stabilized power supply circuit 61 is
To the variable DC voltage source 64,
In this configuration, the output voltage setting circuit 55 is replaced with an output voltage setting circuit 65.

The variable DC voltage source 64 inputs the reference voltage Vref 3 to the comparator 53 so that the reference voltage Vref 3 can take three different levels of the reference voltages Vref 3a, Vref 3b and Vref 3c. The output voltage setting circuit 65 outputs a setting signal b for determining the level of the reference voltage Vref 3 input from the variable DC voltage source 64 to the comparator 53 according to the combination of the control signal a1 and the control signal a2. 64 or a power cutoff signal d to the control unit 2 so that the power supplied to the load becomes zero (output is OFF). Levels of control signals a1, a2 and reference voltages Vref 3a, Vref 3b, Vref 3c
Table 4 shows the correspondence between the output and the output OFF.

[0078]

[Table 4]

In the same table, “H” indicates “High” level, and “L” indicates “Low” level. When the power cutoff signal d is input, the control unit 2 turns off the switches S1 and S3 most simply in order to turn off the output.
State. At this time, the reference voltages Vref 3a and Vref 3
None of b · Vref 3c is input to the comparator 3. Although not shown, the current path of the output transistor Tr1 may be cut off by the signal e.

As described above, according to the stabilized power supply circuit 61 of the present embodiment, the power supply to the load can be reduced to zero and the power consumption can be sufficiently reduced, and the noise of the output voltage Vo 2 can be reduced. Can be sufficiently reduced.

Next, FIG. 8 shows a configuration of a stabilized power supply circuit 71 which is a third example of the stabilized power supply circuit according to the present embodiment. The stabilized power supply circuit 71 is
In which the variable DC voltage source 64 is replaced with a variable DC voltage source 74.

The variable DC voltage source 74 is a DC constant voltage source 74a.
And voltage dividing resistors R31, R32, and R33.
The DC constant voltage source 74a generates the reference voltage Vref 3a, and supplies the reference voltage Vre to the inverting input terminal of the comparator 53.
It is configured to be able to apply and cut off f3a.
The potentials of the voltage dividing resistors R31, R32, and R33 are equal to the reference voltage V.
The voltage dividing resistor R31 is connected in series in this order between one end of the DC constant voltage source 74a serving as the ref 3a and the GND line so as to be on the one end side. And
A connection point between the voltage dividing resistors R31 and R32 is a reference voltage Vref 3b which is a divided voltage of the reference voltage Vref 3a, and a connection point between the voltage dividing resistors R32 and R33 is a reference voltage Vref.
A reference voltage Vref 3c which is a voltage division of the reference voltage 3a is generated, and each of the reference voltages Vref 3b and Vref 3c can be applied to and cut off from the inverting input terminal of the comparator 53.

The output voltage setting circuit 65 supplies the reference voltage Vref 3a · Vref 3b · V to the variable DC voltage source 74 in accordance with the combination of the levels of the control signals a1 and a2.
Which setting signal ref3c should be applied to the inverting input terminal of the comparator 53 is indicated by the setting signal b. The reference voltage Vref 3a · Vref 3b · Vre determined thereby
f 3c, the output voltage Vo is determined by the method described above.
2 is stabilized.

As described above, the comparator 53 and the variable DC voltage source 74 control the stabilization operation of the output voltage by comparing the detected value of the output voltage with the reference voltage, and perform a plurality of operations including the voltage division of the voltage dividing resistor. Of the above-mentioned reference voltage. The number of reference voltages is equal to the reference voltages Vref 3a, Vref 3b, Vref3 as in the present embodiment.
The number is not limited to three, and is provided by the number corresponding to the voltage value of the output voltage Vo2 to be set. The output voltage setting circuit 65
The voltage value Vo (2-1) of the output voltage Vo2 is supplied to the variable DC voltage source 74.
Reference voltage Vref 3a corresponding to Vo (2-2) and Vo (2-3)
By inputting Vref 3b and Vref 3c to the comparator 53, the output voltage Vo2 of the stabilized power supply circuit 71 is set to the above voltage value. That is, the output voltage setting circuit 6
Reference numeral 5 denotes stabilization by selecting, as the reference voltage Vref3 used by the stabilizing operation means for controlling the stabilizing operation of the output voltage Vo2, the voltage division of the voltage dividing resistors R31, R32, and R33 corresponding to the above voltage values. The output voltage Vo2 of the power supply circuit 71 is set to the above voltage value. Voltage dividing resistors R31, R32, R33
As described above, since the setting to the voltage value is performed using the divided voltage of the voltage dividing resistor having a small number of components, the configuration for the setting can be simplified.

[Embodiment 5] An embodiment embodying the device of the present invention will be described below with reference to FIG. Components having the same functions as the components described in the first to fourth embodiments are denoted by the same reference numerals, and description thereof will be omitted.

The device according to the present embodiment is obtained by integrating the integrated portions of the stabilized power supply circuits described in the first to fourth embodiments into one package. As an example, FIG.
(A) is a plan view of a device 81 in which any of the integrated portions 11a, 21a, 41a of the stabilized power supply circuits 11, 21, 31, 41 is packaged, and FIG.
1 shows a side view. The device 81 includes a molded portion 81a made of resin or the like sealing the above-mentioned integrated portion, and lead pins P1, P2,..., P8.
ni Small Outline Package) or VSOP (Very Small O)
utline Package). Lead pins P1 and P2
... P8 is an output terminal T1, an input terminal T2,
Feedback terminal T3, GND terminal T4, capacitor connection terminal T5, control terminal T6, capacitor connection terminal T
7, corresponding to the control terminal T8.

As described above, the device according to the present embodiment is packaged with the integrated portion of the stabilized power supply circuit. Therefore, when the device is mounted on a device as a component, the mounting area is small. The size can be reduced.

[0088]

As described above, the stabilized power supply circuit of the present invention includes the output voltage setting means for setting the output voltage to a voltage value corresponding to the input control signal. Is the voltage value, the power supplied to the load to which the output voltage is applied is at least a value that is a standard supply power and a value that is greater than zero and less than the standard supply power. This is the configuration to be set.

Therefore, when the output voltage is set by the output voltage setting means to a voltage value such that the power supplied to the load is within the above range, the output voltage can be stabilized in comparison with the case where the standard power is always supplied to the load. The power supplied from the power supply that applies the input voltage to the power supply circuit decreases. Therefore, if a method of use that reduces the power supplied to the load is performed, the life of the battery can be extended when a battery is used as the power supply that applies the input voltage to the stabilized power supply circuit. In addition, the life can be sufficiently extended depending on the voltage value set by the output voltage setting means and the usage period of the voltage value.

As described above, there is an effect that it is possible to provide a boosted stabilized power supply circuit capable of securing a sufficient life of a battery when supplying power to a load as a light source.

Further, as described above, the stabilized power supply circuit of the present invention is configured such that the voltage value is a discrete value corresponding to the level of the control signal.

Therefore, it is easy to control the output voltage of the stabilized power supply circuit to the above-mentioned voltage value, and it is possible to keep the types of the above-mentioned voltage values to a practical number. Further, when the generation of the control signal input to the output voltage setting means is left to the selection of the operator, the selection operation is facilitated.

Further, in the stabilized power supply circuit according to the present invention, as described above, a plurality of the control signals are input to the output voltage changing means, and the voltage value is determined according to a combination of the levels of the plurality of control signals. Configuration.

Therefore, the level of the control signal is "Hig
In the case of being represented by "h" and "Low", setting instructions for a large number of the voltage values can be issued with a small number of control signals, such that two control signals can be used to give an instruction for the four voltage values. This has the effect that it can be performed.

Further, as described above, the stabilized power supply circuit of the present invention has a configuration in which the voltage value includes a value at which the supplied power becomes zero.

Therefore, by stopping the operation of the load by setting the supplied power to zero when driving is unnecessary, the power consumption can be further reduced and the life of the battery can be further extended. Play.

Further, as described above, the stabilized power supply circuit of the present invention controls the operation of stabilizing the output voltage by comparing the detected value of the output voltage with the reference voltage and includes the voltage dividing of the voltage dividing resistor. Stabilizing means for generating the plurality of reference voltages, wherein the output voltage setting means selects the divided voltage corresponding to the voltage value as the reference voltage used by the stabilizing means for controlling the stabilizing operation. By doing so, the output voltage is set to the voltage value.

Therefore, the output voltage of the stabilized power supply circuit is set to the above voltage value. Since the voltage value is set by using the voltage divided by the voltage dividing resistor having a small number of components, the configuration for the setting can be simplified.

Further, as described above, the stabilized power supply circuit of the present invention is provided with the series regulator for generating the output voltage.

Therefore, there is an effect that the noise of the output voltage can be sufficiently reduced. In particular, when a light source such as a white LED is used for the load, the power supplied to the load is stabilized, so that a stable light emitting state can be obtained.

The device of the present invention has a configuration in which any one of the stabilized power supply circuits is integrated and packaged.

Therefore, there is an effect that the mounting area can be reduced when the device is mounted as a component on a device, and the size of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a stabilized power supply circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a stabilized power supply circuit of a first example according to a second embodiment of the present invention.

FIG. 3 is a circuit block diagram illustrating a configuration of a stabilized power supply circuit of a second example according to the second embodiment of the present invention.

FIG. 4 is a circuit block diagram showing a configuration of a modified example when a load is connected to the stabilized power supply circuit of FIG. 3;

FIG. 5 is a circuit block diagram illustrating a configuration of a stabilized power supply circuit according to a third embodiment of the present invention.

FIG. 6 is a circuit block diagram showing a configuration of a stabilized power supply circuit of a first example according to a fourth embodiment of the present invention.

FIG. 7 is a circuit block diagram showing a configuration of a stabilized power supply circuit of a second example according to the fourth embodiment of the present invention.

FIG. 8 is a circuit block diagram illustrating a configuration of a stabilized power supply circuit of a third example according to the fourth embodiment of the present invention.

9A is a plan view of a device according to an embodiment of the present invention, and FIG. 9B is a side view of the device.

FIG. 10 is a circuit block diagram showing a configuration of a stabilized power supply circuit according to a first conventional example.

FIG. 11 is a circuit block diagram showing a configuration of a stabilized power supply circuit according to a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stabilized power supply circuit 1a Integrated part (integrated part) 5 Output voltage setting circuit (output voltage setting means) 11 Stabilized power supply circuit 11a Integrated part (integrated part) 15 Output voltage setting circuit (output Voltage setting means) 21 Stabilized power supply circuit 21a Integrated part (integrated part) 25 Output voltage setting circuit (output voltage setting means) 31 Stabilized power supply circuit 32 LED (load) 41 Stabilized power supply circuit 41a Integrated part (Integrated part) 51 Stabilized power supply circuit 51a Integrated part (integrated part) 55 Output voltage setting circuit (output voltage setting means) 61 Stabilized power supply circuit 61a Integrated part (integrated part) 65 Output voltage setting circuit (output voltage setting means) 71 Stabilized power supply circuit 71a Integrated part (integrated part) 81 Device a Control signal a1, a2 Control signal R4, R5, R6 voltage divider R31, R32, R33 voltage divider Vfb1, Vfb2, Vfb3 feedback voltage (detection value) Vin input voltage Vo output voltage Vo2 output voltage Vref 1 reference voltage Vref 2 reference voltage Vref 2a , Vref 2d reference voltage Vref 2b, Vref 2c reference voltage (division) Vref 3 reference voltage Vref 3a, Vref 3d reference voltage Vref 3b, Vref 3c reference voltage (division)

Claims (7)

[Claims] 1. A stabilized power supply circuit for outputting an output voltage generated by stabilizing an input voltage, comprising: output voltage setting means for setting the output voltage to a voltage value according to an input control signal. The output voltage setting means sets the voltage value to a range in which the power supplied to the load to which the output voltage is applied is at least a value that is a supply power defined as a standard, and a value that is greater than zero and less than a supply power defined as a standard. A stabilized power supply circuit, wherein 2. The stabilized power supply circuit according to claim 1, wherein said voltage value is a discrete value corresponding to a level of said control signal. 3. The stability according to claim 2, wherein a plurality of said control signals are input to said output voltage setting means, and said voltage value is in accordance with a combination of a plurality of levels of said control signals. Power circuit. 4. The stabilized power supply circuit according to claim 1, wherein the voltage value includes a value at which the supplied power becomes zero. 5. A stabilizing operation means for comparing a detected value of the output voltage with a reference voltage to control a stabilizing operation of the output voltage and generating a plurality of the reference voltages including a divided voltage of a voltage dividing resistor. The output voltage setting means sets the output voltage to the voltage value by selecting the divided voltage corresponding to the voltage value as the reference voltage used by the stabilizing operation means for controlling the stabilizing operation. The stabilized power supply circuit according to any one of claims 1 to 4, wherein: 6. The stabilized power supply circuit according to claim 1, further comprising a series regulator for generating the output voltage. 7. A device which is packaged with an integrated part of the stabilized power supply circuit according to claim 1.