JP2009064286A - Variable type low-voltage output regulator ic, and linear regulator ic including the same, switching regulator ic and composite regulator ic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable type low-voltage output regulator IC, capable of regulating a second reference voltage value by providing a reference voltage regulating externally attached resistance on the outside thereof, and capable of changing an output voltage value. <P>SOLUTION: This variable type low-voltage output regulator IC capable of obtaining a stable output voltage by controlling an input voltage has a power transistor (Tr) for controlling the input voltage, an operational amplifier (Op) for driving the power transistor (Tr), a first reference voltage generating circuit Vref1 for generating the first reference voltage, a constant current circuit (2), and the second reference voltage regulating internal resistance (Ra) with one end connected to the constant current circuit (2), and with the other end connected to the second reference voltage regulating terminal (7), the first reference voltage (Vref1) is input in one side input of the operational amplifier (Op), and the second reference voltage generated in the other end of the second reference voltage regulating internal resistance (Ra) is input in the other side input of the operational amplifier (Op). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable low-voltage output regulator IC used as a power source for LSIs such as CPUs and DSPs manufactured by a next-generation semiconductor process and various regulator ICs including the variable low-voltage output regulator IC.

  In LSIs (Large Scale Integrated Circuits) such as CPUs (Central Processing Units) and DSPs (Digital Signal Processors) manufactured by the 90-130 nm process, which are currently mainstream, I / O voltages (Ls. The standard configuration is that the voltage required for the operation is 3.3V and the core voltage (the operating voltage of the LSI internal circuit) is 1.2 to 1.8V. In recent years, in an LSI such as a CPU or DSP, the scale of an integrated circuit tends to become larger due to a change / addition of a specification and integration of peripheral circuits. In order to cope with such a trend, semiconductor manufacturers that manufacture these LSIs are responding by further miniaturizing the semiconductor manufacturing process. The latest semiconductor manufacturing process is a 45-65 nm process, and with this, the core voltage is also lowered, and the need for a regulator IC capable of outputting a voltage of 1 V or less is increasing. A regulator IC that supplies a power supply voltage to an LSI such as a CPU or DSP generally has a built-in reference voltage inside the IC. This reference voltage is generally about 1.2 V, and this magnitude is caused by the value of the band gap voltage of silicon and is almost equal to this. The regulator IC performs control such that the output voltage is stabilized based on this voltage.

Patent Document 1 (Japanese Patent Laid-Open No. 2001-195138) has a comparison amplification unit that compares an intermediate voltage of two resistors connected between an output PMOS-FET used as an output and a ground with a reference voltage. A regulator power supply circuit is disclosed which comprises an amplifier circuit using an input power supply or an output as its power supply, and obtains a desired output voltage by controlling the output PMOS-FET.
JP 2001-195138 A

  Incidentally, the main circuit configuration of a linear regulator IC as described in Patent Document 1 is shown in FIG. In FIG. 5, 101 is a reference voltage generating circuit for generating a reference voltage Vref, 102 is an operational amplifier, 103 is a power transistor, 104 and 105 are output voltage adjusting resistors, and 106 is an input power supply voltage to which an input power supply voltage VCC is input. A terminal 107 is an output voltage terminal from which an output voltage VOUT is output, and 108 is a ground terminal.

  In such a circuit configuration, the linear regulator IC performs output control so that the output voltage (VOUT) becomes equal to the reference voltage (Vref) of the negative input (−) and the positive input (+) of the operational amplifier. The output voltage in the case of this circuit configuration can be expressed by the following equation (1).

VOUT = Vref × (1 + R1 / R2) (1)
According to Expression (1), in order to minimize the output voltage VOUT, R1 = 0Ω or R2 may be set to infinity (∞). In such a case, VOUT = Vref, and the output voltage becomes the minimum value. However, in such a circuit configuration of the linear regulator IC, it is impossible to output a voltage equal to or lower than the reference voltage (Vref) as can be seen from the equation (1).

In order to obtain an output voltage of 1 V or less with such a linear regulator IC in order to cope with an LSI manufactured by the latest semiconductor manufacturing process that requires supply of a power supply voltage of 1 V or less, it is generated by a reference voltage generation circuit. The reference voltage Vref to be generated should be 1 V or less. In order to realize such a reference voltage,
In the manufacturing process, it is necessary to perform a correction operation such as laser trimming on individual ICs, to form an adjustment method, to form a correction circuit, and to adopt a method such as a method of lowering the reference voltage. A regulator IC with a reference voltage of 0.7 to 0.9 V using these methods currently exists, but there is a problem that the manufacturing cost increases due to the addition of adjustment work and additional circuits. there were.

  The present invention solves the above-described problem, and uses the current process to output an output voltage equal to or lower than the reference voltage without lowering the reference voltage. The variable low-voltage output according to the embodiment of the present invention Various regulator ICs including a regulator IC and its variable low-voltage output regulator IC are provided. To this end, the invention according to claim 1 of the present application is a variable that obtains a stabilized output voltage by controlling an input voltage. Type low voltage output regulator IC, a power transistor for controlling an input voltage, an operational amplifier for driving the power transistor, a first reference voltage generating circuit for generating a first reference voltage, a constant current circuit, one end A second reference voltage adjusting resistor having one side connected to the constant current circuit and the other end connected to the external connection terminal, and one input of the operational amplifier The inputs the reference voltage of the first, to the other input of the operational amplifier, characterized by inputting the second reference voltage generated at the other end of the second reference voltage adjusting resistor.

  The invention according to claim 2 is a switching regulator IC comprising the configuration of the variable low-voltage output regulator IC according to claim 1.

  The invention according to claim 3 is a composite regulator IC that includes a plurality of regulator circuits in the same IC package and outputs a plurality of types of voltages, and the regulator circuit that outputs the lower voltage includes a linear regulator. A circuit is used, and the configuration of the variable low voltage output regulator IC according to claim 1 is used for the linear regulator circuit.

  According to a fourth aspect of the present invention, there is provided a composite regulator IC having a plurality of regulator circuits in the same IC package and outputting a plurality of types of voltages, wherein the regulator circuit outputting the lower voltage has a switching regulator. A circuit is used, and the configuration of the variable low voltage output regulator IC according to claim 1 is used for the switching regulator circuit.

  According to the present invention, it is manufactured in a next-generation semiconductor process by extending an existing process without performing adjustment work such as laser trimming on individual ICs in the manufacturing process and without forming an additional circuit. It is possible to provide a low voltage output regulator used as a power source for LSIs such as CPUs and DSPs. According to the present invention, the second reference voltage value (Vref2) is adjusted by externally attaching the second reference voltage adjustment external resistor using the second reference voltage adjustment terminal, and the value of VOUT is changed. It becomes possible to do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a main circuit configuration of a variable low voltage output regulator IC according to an embodiment of the present invention. In FIG. 1, 1 is a first reference voltage generating circuit for generating a first reference voltage Vref1, 2 is a constant current circuit for generating a second reference voltage Vref2, Op is an operational amplifier, Tr is a power transistor, R1, R2 is an output voltage adjustment resistor, R3 is an operation stabilization resistor, Ra is a second reference voltage adjustment internal resistor, Rb is a second reference voltage adjustment external resistor, 7 is a second reference voltage adjustment terminal, and 8 is An input power supply voltage terminal to which the input power supply voltage VCC is input, 9 is an output voltage terminal from which the output voltage VOUT is output, and 10 is a ground terminal. The output voltage adjustment resistors R1 and R2 have resistance values R1 and R2, respectively, the operation stabilization resistor R3 has resistance value R3, the second reference voltage adjustment internal resistor Ra has resistance value Ra, Further, it is assumed that the second reference voltage adjusting external resistor Rb has a resistance value Rb. The voltage value of the first reference voltage generation circuit 1 is Vref1—for example, 1.25 V—, and the current value generated by the constant current circuit 2 is Io—for example, 10 μA—. In the case of the circuit configuration of the low voltage output regulator circuit of the present embodiment, the output voltage VOUT can be obtained by the following equation (2).

VOUT = Vref1 + {Vref1-Io (Ra + Rb)} × R1 / R2 (2)
From this equation (2), it can be seen that in the low voltage output regulator circuit system of the present embodiment, an output voltage VOUT lower than Vref1 can be obtained if Vref1 <Io (Ra + Rb). Here, the second reference voltage adjusting internal resistor Ra is built in the regulator IC, and the second reference voltage adjusting external resistor Rb is externally connected using the second reference voltage adjusting terminal 7. By doing so, the value of Io (Ra + Rb) —the second reference voltage value (Vref2) —can be adjusted. That is, according to the present embodiment, the value of VOUT can be changed by replacing the second reference voltage adjusting external resistor Rb.

  In the present embodiment, in addition to the first reference voltage (Vref1), a constant current circuit 2 that can generate a second reference voltage (Vref2) higher than the first reference voltage (Vref1). By providing the second reference voltage adjusting internal resistor Ra inside the regulator IC, it is possible to output an output voltage VOUT lower than the first reference voltage (Vref1). Since it is not technically difficult to provide the constant current circuit 2 and the second reference voltage adjusting internal resistor Ra inside the regulator IC, the linear regulator IC having the circuit configuration of the low voltage output regulator circuit according to the present embodiment. It is easier to manufacture the device than the various methods described above.

As an example, a calculation method of the output voltage adjustment resistors R1 and R2 when 1 V is obtained as the output voltage VOUT will be described. Assuming that the first reference voltage Vref1 is 1.25V, the constant current circuit 2 is 10 μA, and Ra + Rb is 250 kΩ, the second reference voltage Vref2 is 2.5V. Further, the resistance value of the output voltage adjusting resistor R1 is set appropriately. Here, when R1 = 1 KΩ, the following equation (3) obtained by modifying equation (2):
R2 = (Vref1−Vref2) × R1 / (VOUT−Vref1) (3)
R2 = (1.25V−2.5V) × 1KΩ / (1V−1.25V) = 5kΩ
Can be obtained.

  Next, the value of the operation stabilization resistor R3 is obtained. The operation stabilization resistor R3 is a resistor for maintaining the constant voltage operation even when the output load is removed, and is a resistor for suppressing the rise of VOUT to VCC when there is no load.

R3 = VOUT × R1 / (Vref1-VOUT) (4)
When each numerical value is applied to Equation (4), R3 = 1V × 1KΩ / (1.25V-1V) = 4KΩ
Can be obtained. In the above example, the case where 1 V is obtained as the output voltage VOUT is shown as an example. However, in this embodiment, the output voltage adjusting resistors R1 and R2, the operation stabilizing resistor R3, and the second reference voltage adjusting internal resistor Ra. The output voltage can be output up to nearly 0 V as the output voltage VOUT by variously changing the resistance value. Furthermore, the second reference voltage value (Vref2) can be adjusted by externally attaching the second reference voltage adjusting external resistor Rb using the second reference voltage adjusting terminal 7. That is, according to the present embodiment, the value of VOUT can be changed also by replacing the second reference voltage adjusting external resistor Rb.

  Next, the case where the variable low voltage output regulator IC of the present invention is applied to a switching regulator IC will be described. In the case of the linear regulator IC, excess power generated when the voltage is stepped down is converted into heat and released. For example, when a 1V output voltage is extracted from an input voltage of 5V, if a current of 200 mA flows, P = (5V-1V) × 0.2A = 0.8W, resulting in a heat loss of 0.8W. Become. Thus, in the case of a linear regulator, as the output current increases, the heat loss increases proportionally. For this reason, it is not appropriate to use a linear regulator IC as a regulator having a large input / output voltage difference and a large output current.

  In order to improve the voltage conversion efficiency of this linear regulator IC, it is effective to use a switching regulator system. An example in which the low voltage output regulator circuit of the present invention is applied to a switching regulator IC will be described below.

  FIG. 2 is a diagram showing a main configuration of a switching regulator IC to which the variable low voltage output regulator IC circuit according to the embodiment of the present invention is applied. In FIG. 2, the switching regulator IC itself is the portion enclosed in the right frame and up to each terminal. As shown in the figure, an external circuit connected to each terminal is added and the whole is used as a switching regulator. It is.

  In FIG. 2, 11 is a first reference voltage generating circuit for generating a first reference voltage Vref1, 12 is a constant current circuit for generating a second reference voltage Vref2, Op1 is a first operational amplifier, and Op2 is a first reference voltage. 2 operational amplifiers, 15 a pre-driver, 16 a power transistor, 17 a transmitter, 18 a soft start, R1 and R2 are output voltage adjustment resistors, Ra is a second reference voltage adjustment internal resistor, and Rb is a second An external resistor for reference voltage adjustment, 21 is an input power supply voltage terminal to which the input power supply voltage VCC is input, 22 is an output terminal, 23 is a feedback terminal, 24 is a capacitor connection terminal for phase compensation, 25 is a ground terminal, and 26 is a first terminal. 2 Reference voltage adjustment terminal, D is a diode, L is a coil, C1 is a capacitor, C2 is a phase compensation capacitor, 30 is an output terminal as a switching regulator circuit It is.

  The output voltage adjusting resistors R1 and R2 have resistance values of R1 and R2, respectively, the second reference voltage adjusting internal resistor Ra has a resistance value of Ra, and the second reference voltage adjusting external resistor Rb is a resistor. Assume that the value has Rb. The voltage value of the first reference voltage generation circuit 1 is Vref1—for example, 1.25 V—, and the current value generated by the constant current circuit 2 is Io—for example, 10 μA—. In addition, the voltage value, each resistance value, etc. which are shown in a figure show one of the Examples.

  An outline of the operation of the circuit of the switching regulator IC of FIG. 2 will be described. The on / off control of the power transistor 10 is performed by the first operational amplifier Op 1, the pre-driver 15, and the transmitter 17.

  For the input of the soft start 18, the output of the second operational amplifier Op2 phase-compensated by the phase compensation capacitor 29 is used. As a circuit until the output from the second operational amplifier Op2 is obtained, the circuit configuration of the variable low voltage output regulator IC of the present embodiment is used. That is, as described above, as the output of the second operational amplifier Op2, the first reference voltage generating circuit 11, the output voltage adjusting resistors R1, R2, and the second reference voltage adjusting internal resistor for determining the second reference voltage are used. A desired low voltage can be obtained by adjusting Ra and the second reference voltage adjusting external resistor Rb.

  Also in the present embodiment, the second reference voltage adjusting internal resistor Ra is configured in the switching regulator IC, and the second reference voltage adjusting external resistor 26 is used by using the second reference voltage adjusting terminal 26. By attaching Rb externally, the value of Io (Ra + Rb) —the second reference voltage value (Vref2) —can be adjusted. That is, according to the present embodiment, the value of VOUT can be changed by replacing the second reference voltage adjusting external resistor Rb.

  The output of the soft start 18 is input to the inverting input terminal of the first operational amplifier Op1, and the output signal of the oscillator 17 is input to the non-inverting input terminal of the first operational amplifier Op1.

  The first operational amplifier Op1 compares the output signal from the soft start 18 and the output waveform from the oscillator 17. The output of the pre-driver 15 turns on / off the power transistor 16 connected to the pre-driver 15 in synchronization with the frequency of the oscillator 17. By continuously performing these operations, the output voltage is stabilized.

  The soft start 18 is provided with an output voltage provided for the purpose of preventing the power transistor 16 from being damaged by a rush current flowing into the capacitor 28 when the input power is turned on and for preventing the output voltage rising waveform from overshooting. It is a protection circuit that performs control to gradually and smoothly start up.

  The basic voltage setting method is the same principle as in the case of the linear regulator IC, and the output voltage and the output voltage adjusting resistors R1 and R2 are obtained by equations (2) and (3). Further, unlike the case of the linear regulator IC, it is not necessary to connect the operation stabilization resistor R3. In the case of the frequency synchronous switching regulator, since the current is discharged and sucked by an external coil / diode, Vout does not rise to Vcc when there is no load, and the operation stabilization resistor R3 can be omitted.

  Next, a case where the variable low voltage output regulator IC of the present invention is applied to a composite regulator IC will be described. As described in the “Background Art” section, there are LSIs such as DSPs and CPUs that require two power supplies, an I / O voltage and a core voltage. It is highly desirable to be able to supply both the core voltage.

  FIG. 3 is a diagram showing a main configuration of a composite regulator IC to which the variable low voltage output regulator IC circuit according to the embodiment of the present invention is applied. FIG. 3 shows a configuration example in which two linear regulators are built in the same IC package and voltage output of 3.3V and 1V is possible. The number of linear regulators provided in the same IC package is not limited to two circuits, and a plurality of linear regulators may be provided. In short, the variable low-voltage output regulator IC circuit of the present invention may be applied to a low one of a plurality of types of voltages output from the linear regulator.

  In FIG. 3, 31 is a first reference voltage generating circuit for generating a first reference voltage Vref1, 32 is a constant current circuit for generating a second reference voltage Vref2, Op1 is a first operational amplifier, and Op2 is a first reference voltage. 2 operational amplifiers, R1 and R2 are output voltage adjustment resistors, R3 is an operation stabilization resistor, R4 and R5 are output voltage adjustment resistors, Ra is a second reference voltage adjustment internal resistor, and Rb is a second reference voltage adjustment. External resistors, Tr1 and Tr2 are power transistors, 42 is an input power supply voltage terminal to which an input power supply voltage VCC is input, 43 is a first output voltage terminal from which an output voltage VOUT1 is output to output an I / O voltage, Reference numeral 44 denotes a second output voltage terminal from which an output voltage VOUT2 for outputting the core voltage is output, 45 denotes a ground terminal, and 46 denotes a second reference voltage adjustment terminal.

  The output voltage adjusting resistors R1, R2, R3, and R4 have resistance values of R1, R2, R3, and R4, the operation stabilizing resistor R3 has a resistance value of R3, and the second reference voltage adjusting internal resistor Ra is It is assumed that Ra has a resistance value, and the second reference voltage adjusting external resistor Rb has a resistance value Rb. The voltage value of the first reference voltage generation circuit 1 is Vref1—for example, 1.25 V—, and the current value generated by the constant current circuit 2 is Io—for example, 10 μA—. The voltage values, resistance values, etc. shown in the figure show one of the embodiments.

  As shown in FIG. 3, the circuit shown in FIG. 5 shown as a conventional linear regulator circuit is used as the circuit for outputting the 3.3V I / O voltage, and the core voltage of 1V is used. The variable low voltage output regulator IC according to the present embodiment using the first reference voltage Vref1 and the second reference voltage Vref2 generated by the constant current circuit 32 is used as a circuit for outputting the signal. .

  In the present embodiment, as described above, as the output of the second operational amplifier Op2, as described above, the first reference voltage generation circuit 11, the output voltage adjustment resistors R1 and R2, and the second reference voltage for determining the second reference voltage. A desired low voltage can be obtained by adjusting the adjustment internal resistance Ra and the second reference voltage adjustment external resistance Rb.

  Also in the present embodiment, the second reference voltage adjusting internal resistor Ra is configured in the switching regulator IC, and the second reference voltage adjusting terminal 26 is used to remove the second reference voltage adjusting internal resistor Ra. The value of Io (Ra + Rb) —the second reference voltage value (Vref2) —can be adjusted by externally attaching the attachment resistor Rb. That is, according to the present embodiment, the value of VOUT can be changed by replacing the second reference voltage adjusting external resistor Rb.

  FIG. 4 is a diagram showing a main configuration of a composite regulator IC to which the variable low voltage output regulator IC circuit according to the embodiment of the present invention is applied. FIG. 4 shows a configuration example in which a linear regulator circuit and a step-down switching regulator circuit are built in the same IC package and voltage outputs of 3.3 V and 1 V are possible. Note that the regulator circuit provided in the same IC package is not necessarily limited to the two circuits of the linear regulator and the step-down switching regulator, and a plurality of regulator circuits may be provided. In short, the variable low voltage output regulator IC of the present invention may be applied to a low one of a plurality of types of voltages output from the regulator circuit. In FIG. 4, the switching regulator IC itself is a portion surrounded by a right frame and up to each terminal. As shown, an external circuit connected to each terminal is added and the whole is used as a switching regulator. It is.

  In FIG. 4, 51 is a first reference voltage generating circuit for generating a first reference voltage Vref1, 52 is a constant current circuit for generating a second reference voltage Vref2, Op1 is a first operational amplifier, and Op2 is a second reference voltage. An operational amplifier, 55 is a pre-driver, Tr1 and Tr2 are power transistors, 58 is a soft start, 59 is a transmitter, R1 and R2 are output voltage adjustment resistors, R4 and R5 are output voltage adjustment resistors, and Ra is a second reference. Internal resistor for voltage adjustment, Rb is an external resistor for adjusting the second reference voltage, D is a diode, L is a coil, C1 is a capacitor, C2 is a phase compensation capacitor, and 65 is an input power supply voltage to which the input power supply voltage VCC is input Terminal, 66 is a first output voltage terminal that outputs a core voltage, 67 is a feedback terminal, 68 is a phase compensation capacitor connection terminal, and 69 is a second output that outputs an I / O voltage. The power voltage terminal, 70 is a ground terminal, and 71 is a second reference voltage adjusting terminal.

  The output voltage adjustment resistors R1, R2, R3, and R4 have resistance values of R1, R2, R3, and R4, respectively, the second reference voltage adjustment internal resistor Ra has a resistance value of Ra, and a second reference voltage adjustment resistor It is assumed that the external resistor Rb has Rb as a resistance value. The voltage value of the first reference voltage generation circuit 1 is Vref1—for example, 1.25 V—, and the current value generated by the constant current circuit 2 is Io—for example, 10 μA—. In addition, the voltage value, each resistance value, etc. which are shown in a figure show one of the Examples.

  As shown in FIG. 4, the circuit shown in FIG. 5 shown as a conventional linear regulator circuit is used as the circuit for outputting the 3.3V I / O voltage, and the core voltage of 1V is used. The variable low voltage output regulator IC according to the present embodiment using the first reference voltage Vref1 and the second reference voltage Vref2 generated by the constant current circuit 32 is used as a circuit for outputting the signal. . In this composite regulator IC, the voltage conversion efficiency is improved by adopting a switching method for a power supply portion for outputting a core voltage of 1 V having a large input / output voltage difference.

  In the present embodiment, as described above, as the output of the first operational amplifier Op2, as described above, the first reference voltage generation circuit 11, the output voltage adjusting resistors R1 and R2, and the second reference voltage for determining the second reference voltage. A desired low voltage can be obtained by adjusting the adjustment internal resistance Ra and the second reference voltage adjustment external resistance Rb.

  Also in the present embodiment, the second reference voltage adjusting internal resistor Ra is configured in the switching regulator IC, and the second reference voltage adjusting external resistor 26 is used by using the second reference voltage adjusting terminal 26. By attaching Rb externally, the value of Io (Ra + Rb) —the second reference voltage value (Vref2) —can be adjusted. That is, according to the present embodiment, the value of VOUT can be changed by replacing the second reference voltage adjusting external resistor Rb.

It is a figure which shows the main circuit structure of the variable type low voltage output regulator IC which concerns on embodiment of this invention. It is a figure which shows the main structures of the switching regulator IC to which the circuit of the variable type low voltage output regulator IC which concerns on embodiment of this invention is applied. It is a figure which shows the main structures of the composite regulator IC to which the circuit of the variable type low voltage output regulator IC which concerns on embodiment of this invention is applied. It is a figure which shows the main structures of the composite regulator IC to which the circuit of the variable type low voltage output regulator IC which concerns on embodiment of this invention is applied. It is a figure which shows the main circuit structure of the conventional linear regulator IC.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st reference voltage generation circuit, 2 ... Constant current circuit, Op ... Operational amplifier, Tr ... Power transistor, R1, R2 ... Output voltage adjustment resistor, R3 ... Operation Stabilizing resistor, Ra ... second reference voltage adjusting internal resistor, Rb ... second reference voltage adjusting external resistor, 7 ... second reference voltage adjusting terminal, 8 ... input power supply voltage Terminals 9 ... Output voltage terminals 10 ... Ground terminals 11 ... First reference voltage generating circuit 12 ... Constant current circuit Op1 ... First operational amplifier Op2 ... Second operational amplifier, 15 ... pre-driver, 16 ... power transistor, 17 ... transmitter, 18 ... soft start, R1, R2 ... resistance for adjusting output voltage, Ra ... Internal resistor for adjusting the second reference voltage, Rb ... External for adjusting the second reference voltage 21 ... input power supply voltage terminal, 22 ... output terminal, 23 ... feedback terminal, 24 ... phase compensation capacitor connection terminal, 25 ... ground terminal, 26 ... second reference Voltage adjusting terminal, D ... diode, L ... coil, C1 ... capacitor, C2 ... phase compensation capacitor, 30 ... output terminal, 31 ... first reference voltage generating circuit, 32... Constant current circuit, Op1... First operational amplifier, Op2... Second operational amplifier, R1, R2... Output voltage adjustment resistor, R3... Operation stabilization resistor, R4, R5 ... Output voltage adjustment resistor, Ra ... Second reference voltage adjustment internal resistor, Rb ... Second reference voltage adjustment external resistor, Tr1, Tr2 ... Power transistor, 42 ... Input Power supply voltage terminal, 43... First output voltage terminal, 44 .. Second output voltage terminal, 45... Ground terminal, 46... Second reference voltage adjustment terminal, 51... First reference voltage generation circuit, 52. First operational amplifier, Op2 ... second operational amplifier, 55 ... pre-driver, Tr1, Tr2 ... power transistor, 58 ... soft start, 59 ... transmitter, R1, R2 ... Output voltage adjusting resistor, R4, R5 ... Output voltage adjusting resistor, Ra ... Second reference voltage adjusting internal resistor, Rb ... Second reference voltage adjusting external resistor, D ... Diode , L ... coil, C1 ... capacitor, C2 ... phase compensation capacitor, 65 ... input power supply voltage terminal, 66 ... first output voltage terminal, 67 ... feedback terminal, 68. ..Phase compensation capacitor connection terminals, 69 A second output voltage terminal for outputting the / O voltage, 70 ... ground terminal, 71 ... second reference voltage adjusting terminal

Claims (4)

In a variable low voltage output regulator IC that obtains a stabilized output voltage by controlling an input voltage,
A power transistor for controlling the input voltage;
An operational amplifier for driving the power transistor;
A first reference voltage generating circuit for generating a first reference voltage;
A constant current circuit;
A second reference voltage adjusting resistor having one end connected to the constant current circuit and the other end connected to an external connection terminal;
The first reference voltage is input to one input of the operational amplifier,
A variable low voltage output regulator IC, wherein a second reference voltage generated at the other end of the second reference voltage adjusting resistor is input to the other input of the operational amplifier. A switching regulator IC comprising the variable low-voltage output regulator IC according to claim 1. A composite regulator IC that includes a plurality of regulator circuits in the same IC package and outputs a plurality of types of voltages, and a linear regulator circuit is used for the regulator circuit that outputs the lower voltage, and A composite regulator IC, wherein the linear regulator circuit uses the configuration of the variable low-voltage output regulator IC according to claim 1. A composite regulator IC that includes a plurality of regulator circuits in the same IC package and outputs a plurality of types of voltages, wherein a regulator circuit that outputs a lower voltage uses a switching regulator circuit, and A composite regulator IC, wherein the switching regulator circuit uses the configuration of the variable low-voltage output regulator IC according to claim 1.

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