Abstract: Provided is a voltage regulator having satisfactory transient response characteristics. The voltage regulator includes: a first amplifier for detecting that undershoot occurs in an output voltage; a second amplifier for detecting that overshoot occurs in the output voltage; a first constant current circuit for increasing a bias current of an error amplifier circuit by a first amount for a first time period in response to a signal determined based on one of an output signal of the first amplifier and an output signal of the second amplifier; a second constant current circuit for increasing the bias current of the error amplifier circuit by a second amount larger than the first amount for a second time period shorter than the first time period in response to a signal determined based on the output signal of the first amplifier; and a first switch circuit for pulling up a gate of an output transistor in response to a signal determined based on the output signal of the second amplifier.

Abstract: Provided is a voltage regulator capable of stably suppressing overshoot. The voltage regulator includes a non-regulated state detection circuit for detecting a non-regulated state, and an overshoot suppression circuit. The overshoot suppression circuit is configured to operate when the non-regulated state detection circuit detects the non-regulated state.

Abstract: Provided is a voltage regulator having satisfactory transient response characteristics. The voltage regulator includes: a first amplifier for detecting that undershoot occurs in an output voltage; a second amplifier for detecting that overshoot occurs in the output voltage; a first constant current circuit for increasing a bias current of an error amplifier circuit by a first amount for a first time period in response to a signal determined based on one of an output signal of the first amplifier and an output signal of the second amplifier; a second constant current circuit for increasing the bias current of the error amplifier circuit by a second amount larger than the first amount for a second time period shorter than the first time period in response to a signal determined based on the output signal of the first amplifier; and a first switch circuit for pulling up a gate of an output transistor in response to a signal determined based on the output signal of the second amplifier.

Abstract: Provided is a voltage regulator having satisfactory transient response characteristics. The voltage regulator includes: a first amplifier for detecting that undershoot occurs in an output voltage; a second amplifier for detecting that overshoot occurs in the output voltage; a first constant current circuit for increasing a bias current of an error amplifier circuit by a first amount for a first time period in response to a signal determined based on one of an output signal of the first amplifier and an output signal of the second amplifier; a second constant current circuit for increasing the bias current of the error amplifier circuit by a second amount larger than the first amount for a second time period shorter than the first time period in response to a signal determined based on the output signal of the first amplifier; and a first switch circuit for pulling up a gate of an output transistor in response to a signal determined based on the output signal of the second amplifier.

Abstract: Provided is a voltage regulator having a simple circuit configuration in which a protection circuit is not erroneously operated, and delay time of activation of the protection circuit is short. The voltage regulator includes: a protection circuit configured to control an output transistor when an abnormality of the voltage regulator is detected; a first constant current circuit configured to supply operating current to the protection circuit; and a detection circuit configured to detect output current flowing through the output transistor, to thereby control the first constant current circuit. The detection circuit is further configured to detect the output current with a predetermined reference current value. The protection circuit is further configured to control the output transistor so that the output current does not fall below the reference current value.

Abstract: Provided is a voltage regulator having a simple circuit configuration in which a protection circuit is not erroneously operated, and delay time of activation of the protection circuit is short. The voltage regulator includes: a protection circuit configured to control an output transistor when an abnormality of the voltage regulator is detected; a first constant current circuit configured to supply operating current to the protection circuit; and a detection circuit configured to detect output current flowing through the output transistor, to thereby control the first constant current circuit. The detection circuit is further configured to detect the output current with a predetermined reference current value. The protection circuit is further configured to control the output transistor so that the output current does not fall below the reference current value.

Abstract: Provided is a voltage regulator that is low in current consumption and is capable of suppressing the occurrence of an excessive overshoot at an output terminal when a power supply voltage becomes high in a non-regulated state. The voltage regulator includes: an overshoot limiting circuit for detecting an occurrence of an overshoot in an output voltage and limiting a current of the output transistor; and a non-regulated state detection circuit for detecting a non-regulated state of the voltage regulator based on a voltage of an output terminal and a current flowing through the output transistor. The overshoot limiting circuit has an operating current controlled by a detection signal of the non-regulated state detection circuit.

Abstract: Provided is a voltage regulator capable of stably suppressing overshoot. The voltage regulator includes a non-regulated state detection circuit for detecting a non-regulated state, and an overshoot suppression circuit. The overshoot suppression circuit is configured to operate when the non-regulated state detection circuit detects the non-regulated state.

Abstract: Provided is a voltage regulator that is low in current consumption and is capable of suppressing the occurrence of an excessive overshoot at an output terminal when a power supply voltage becomes high in a non-regulated state. The voltage regulator includes: an overshoot limiting circuit for detecting an occurrence of an overshoot in an output voltage and limiting a current of the output transistor; and a non-regulated state detection circuit for detecting a non-regulated state of the voltage regulator based on a voltage of an output terminal and a current flowing through the output transistor. The overshoot limiting circuit has an operating current controlled by a detection signal of the non-regulated state detection circuit.

Abstract: Provided is a voltage regulator having satisfactory transient response characteristics. The voltage regulator includes: a first amplifier for detecting that undershoot occurs in an output voltage; a second amplifier for detecting that overshoot occurs in the output voltage; a first constant current circuit for increasing a bias current of an error amplifier circuit by a first amount for a first time period in response to a signal determined based on one of an output signal of the first amplifier and an output signal of the second amplifier; a second constant current circuit for increasing the bias current of the error amplifier circuit by a second amount larger than the first amount for a second time period shorter than the first time period in response to a signal determined based on the output signal of the first amplifier; and a first switch circuit for pulling up a gate of an output transistor in response to a signal determined based on the output signal of the second amplifier.

Abstract: Provided is a voltage regulator capable of performing appropriate phase compensation. Even when a difference between an input voltage and an output voltage is small, an appropriate phase compensation voltage based on an output voltage (Vout) is generated in a resistor circuit (19), and the appropriate phase compensation voltage is applied to a phase compensation capacitor (20). Accordingly, the voltage regulator is capable of performing appropriate phase compensation.

Abstract: Provided is a voltage regulator capable of performing appropriate phase compensation. Even when a difference between an input voltage and an output voltage is small, an appropriate phase compensation voltage based on an output voltage (Vout) is generated in a resistor circuit (19), and the appropriate phase compensation voltage is applied to a phase compensation capacitor (20). Accordingly, the voltage regulator is capable of performing appropriate phase compensation.

Abstract: A voltage regulator according to the present invention is operated stably. Regardless of a condition of a load (25), a variation in drain voltage of a PMOS transistor (34) is made equal to a variation in output voltage (Vout) at an output terminal of the voltage regulator. Then, a variation in voltage which is equal to the variation in output voltage (Vout) at the output terminal which is caused by a change of the condition of the load (25) is fed back to an error amplifier (70), so a gain of a signal for phase compensation which is fed back to the error amplifier (70) is determined based on the output voltage (Vout). Therefore, even when the condition of the load (25) changes, the behavior of phase compensation is correct.