VOLTAGE REGULATOR

• US 20140253076A1
• Filed: 03/04/2014
• Published: 09/11/2014
• Est. Priority Date: 03/06/2013
• Status: Active Grant

• Current Assignee: Ablic Inc. (MinebeaMitsumi Inc.)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: UTSUNOMIYA, Fumiyasu
• Granted Patent: US 9,812,958 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: G05F 1/565 sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor G05F1/563 takes precedence
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

Provided is a voltage regulator capable of, when an overshoot or undershoot occurs in an output voltage, improving the overshoot or undershoot in a wide temperature range and reducing a delay in detection of the overshoot or undershoot. The voltage regulator includes: an error amplifier; an output transistor; and a first transistor including a gate for inputting a reference voltage and a source for inputting an output voltage. The first transistor is configured to cause a current to flow when the output voltage becomes an irregular voltage, and a current of the output transistor is controlled based on the current flowing through the first transistor.

Claims

1. A voltage regulator, comprising:

an error amplifier;

an output transistor; and

a first transistor including a gate for inputting a reference voltage and a source for inputting an output voltage,

wherein the first transistor is configured to cause a current to flow when the output voltage becomes an irregular voltage, and a current of the output transistor is controlled based on the current flowing through the first transistor.

2. A voltage regulator according to claim 1, further comprising an I-V converter circuit configured to control the current flowing through the output transistor based on a current controlled by an output of the error amplifier and the current flowing through the first transistor.

3. A voltage regulator according to claim 2, wherein:

the I-V converter circuit comprises a second transistor controlled by the output of the error amplifier; and

the current flowing through the output transistor is controlled based on a current flowing through the second transistor.

4. A voltage regulator according to claim 3, wherein the I-V converter circuit further comprises a third transistor for causing a current to flow through the output transistor, the current being based on the current flowing through the second transistor and the current flowing from the first transistor.

5. A voltage regulator according to claim 3, wherein the second transistor includes a gate connected to the output of the error amplifier and a drain connected to a gate of the output transistor.

6. A voltage regulator according to claim 4, wherein the third transistor includes a gate and a drain connected to a gate of the output transistor.

7. A voltage regulator according to claim 2, wherein the current flowing through the first transistor is transmitted to the I-V converter circuit via a mirror circuit.

8. A voltage regulator according to claim 4, wherein the I-V converter circuit comprises a cascode transistor provided between the second transistor and the third transistor.