Power supply circuit and semiconductor device

• US 9,152,159 B2
• Filed: 01/27/2014
• Issued: 10/06/2015
• Est. Priority Date: 03/18/2013
• Status: Active Grant

• Current Assignee: Socionext Inc.
• Original Assignee: Socionext Inc.
• Inventors: Yoshioka, Akihito, Kamiya, Kazuhiro
• Primary Examiner(s): Dole, Timothy J
• Assistant Examiner(s): AHMED, YUSEF A
• Application Number:
  US14/165,074
• Publication Number:
  US 20140269136A1
• Time in Patent Office: 617 Days
• US Class Current: 1/1
• CPC Class Codes: G05F 1/467 Sources with noise compensation
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence
• 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: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: G11C 5/14 Power supply arrangements , e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels
• CPC Class Codes: G11C 5/147 Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops G11C5/141 takes precedence

Abstract

An output transistor coupled between an input terminal where an input voltage is input and an output terminal where an output voltage is output; an error amplifier configured to generate a first error signal and a second error signal based on a voltage in accordance with the output voltage and a reference voltage, and to output the first error signal to a gate terminal of the output transistor; an anti-overshoot circuit coupled to the output terminal and controlled by the second error signal; an output transistor control part configured to add a control signal based on a first current in accordance with an AC component of the output voltage to the first error signal; and a sensitivity adjustment part configured to decrease the first current based on the second error signal when the output voltage is higher than a certain voltage.

Claims

1. A power supply circuit, comprising:

a first transistor coupled between an input terminal where an input voltage is input and an output terminal where an output voltage is output;

an error amplifier configured to generate a first error signal and a second error signal based on a difference voltage between a voltage in accordance with the output voltage and a reference voltage, and to output the first error signal to a gate terminal of the first transistor;

a control circuit configured to add a control signal based on a first current in accordance with an AC component of the output voltage to the first error signal; and

an adjustment circuit configured to decrease the first current based on the second error signal when the output voltage is higher than a certain voltage.

2. The power supply circuit according to claim 1,

wherein the adjustment circuit includes a resistance part coupled to a node where the first current flows and whose resistance value is controlled based on the second error signal.

3. The power supply circuit according to claim 2,

wherein the resistance part includes:

a first resistance part and a second resistance part,

wherein the first resistance part and the second resistance part are coupled to the node where the first current flows in parallel when the output voltage is higher than the predetermined voltage, and the first resistance part is coupled to the node where the first current flows when the output voltage is the predetermined voltage or less.

4. The power supply circuit according to claim 3,

wherein the first resistance part includes a first resistance coupled to the node where the first current flows, and

the second resistance part includes a series circuit coupled to the node where the first current flows, and

the series circuit includes a third transistor in which the second error signal is supplied to a gate terminal and a second resistance coupled in series.

5. The power supply circuit according to claim 3,

wherein a resistance value of the first resistance part is controlled based on the output voltage of the power supply circuit at an operation start time.

6. The power supply circuit according to claim 5,

wherein the first resistance part includes:

plural resistances coupled to the node where the first current flows; and

a comparison circuit configured to compare the output voltage of the power supply circuit at the operation start time and one or more threshold voltages, and to switch whether or not each of the resistances are coupled to the node where the first current flows in accordance with a comparison result.

7. A semiconductor device, comprising:

a load; and

a power supply circuit configured to supply electric power to the load,

wherein the power supply circuit including;

a first transistor coupled between an input terminal where an input voltage is input and an output terminal where an output voltage is output;

an error amplifier configured to generate a first error signal and a second error signal based on a difference voltage between a voltage in accordance with the output voltage and a reference voltage, and to output the first error signal to a gate terminal of the first transistor;

a control circuit configured to add a control signal based on a first current in accordance with an AC component of the output voltage to the first error signal; and

an adjustment circuit configured to decrease the first current based on the second error signal when the output voltage is higher than a certain voltage.

8. The semiconductor device according to claim 7,

wherein the load is a memory.

9. The semiconductor device according to claim 7,

wherein the load is a microcontroller.