Power supply device and electronic equipment comprising same

• US 20050122087A1
• Filed: 09/17/2004
• Published: 06/09/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Okubo, Takuya, Sakai, Masaru
• Granted Patent: US 7,161,336 B2
• Time in Patent Office: Days
• US Class Current: 323/271
• 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: Y10S 323/901 Starting circuits

Abstract

The present invention provides a power supply device which can suppress a voltage drop of the input power supply immediately after recovery from shutdown status. The power supply device comprises a reference voltage generation circuit for generating reference voltage (VREF), a transistor for feeding disposed between an input terminal (VTT_IN) and an output terminal (VTT output terminal), a transistor for discharging disposed between a ground potential and a VTT output terminal, a first and second differential amplification circuits for controlling the transistors for feeding and discharging respectively by inputting the output power supply voltage (VTT) as feedback and comparing it with VREF, and a shutdown recovery circuit for generating voltage that gradually starts up by a constant current source and a capacitor, wherein the first differential amplification circuit compares VTT with the voltage (SR) of the shutdown recovery circuit instead of VREF, for a certain period from the point of recovery from shutdown status.

Claims

1. A power supply device for outputting output power supply voltage from an output terminal, comprising:

a reference voltage generation circuit for generating reference voltage;

a first transistor disposed between an input power supply and an output terminal;

a second transistor disposed between a ground potential and an output terminal;

a first and second differential amplification circuits for controlling the first and second transistors respectively by inputting output power supply voltage as feedback and comparing it with the reference voltage that is input from the reference voltage generation circuit; and

a shutdown recovery circuit for generating voltage that gradually starts up, wherein

said first differential amplification circuit compares the output power supply voltage with the voltage of the shutdown recovery circuit instead of the reference voltage, for a certain period from the point of recovery from shutdown status.

2. The power supply device according to claim 1, wherein said shutdown recovery circuit generates voltage that starts up gradually by a constant current source and a capacitor.

3. An electronic equipment comprising the power supply device according to claim 1, a memory device, and a controller, wherein

the memory device and the controller are connected by at least one signal line via a first resistor, and

the output terminal of the power supply device is connected to the memory device side of the signal line via a second resistor as a power supply for termination.

4. An electronic equipment comprising the power supply device according to claim 2, a memory device, and a controller, wherein

the memory device and the controller are connected by at least one signal line via a first resistor, and

the output terminal of the power supply device is connected to the memory device side of the signal line via a second resistor as a power supply for termination.