Reference voltage generating device and generating method of the same

• US 6,337,598 B1
• Filed: 02/29/2000
• Issued: 01/08/2002
• Est. Priority Date: 03/02/1999
• Status: Expired due to Term

• Current Assignee: Longitude Licensing Limited (Vector Capital Corporation)
• Original Assignee: NEC Corporation
• Inventors: Ohno, Kazuki
• Primary Examiner(s): ZWEIZIG, JEFFERY SHAWN
• Application Number:
  US09/515,543
• Time in Patent Office: 679 Days
• Field of Search: 323/265, 323/268, 323/271, 323/272, 323/282, 327/531, 327/536, 327/540, 327/541, 327/544, 327/547, 327/548
• US Class Current: 327/540
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence

Abstract

A reference voltage generating device and method enables dissipation current to be reduced at the time of normal operation. An oscillator outputs a voltage of a low level intermittently during a prescribed time interval. An operational amplifier operates only when an output voltage of the oscillator is a low level. When the output voltage of the oscillator is a high level, a reference voltage “VREF” becomes a floating state so that a level is maintained by compensating the capacity of a capacitor C1. The reference voltage “VREF,” whose electric charge leaks due to a leak at the junction of a transistor, is maintained while operating the operational amplifier during a time interval T in a time period 10 T.

Claims

1. A reference voltage generating device, comprising:

an operational amplifier having an enable terminal; and

an intermittent operating means, provided at said enable terminal, for operating said operational amplifier intermittently only during a prescribed time interval.

2. A reference voltage generating device as claimed in claim 1, wherein said intermittent operating means comprises an oscillator.

3. A reference voltage generating device, comprising:

an operational amplifier which has an enable terminal;

two resistors for determining a feedback voltage which is supplied to said operational amplifier;

a transistor for deciding whether or not a route of said feedback voltage to be disconnected occurs;

a capacitor for stabilizing a reference voltage which is an output voltage of said operational amplifier; and

an intermittent operating means for providing a drive voltage in order to operate said operational amplifier intermittently,

wherein said intermittent operating means is provided at said enable terminal of said operational amplifier.

4. A reference voltage generating device as claimed in claim 3, wherein said intermittent operating means comprises an oscillator.

5. A reference voltage generating method that comprises an operational amplifier having an enable terminal, said method comprising the step of:

operating said operational amplifier intermittently only during a prescribed time interval by means of an intermittent operating means, wherein said intermittent operating means is provided at said enable terminal.

6. A reference voltage generating method that comprises an operational amplifier having an enable terminal, said method comprising the step of:

operating said operational amplifier intermittently only during a prescribed time interval by means of an oscillator, wherein said intermittent operating means is provided at said enable terminal.

7. A reference voltage generating method that comprises an operational amplifier which has an enable terminal, two resistors for determining a feedback voltage which is supplied to said operational amplifier, a transistor for deciding whether or not a route of said feedback voltage to be disconnected occurs, and a capacitor for stabilizing a reference voltage which is an output voltage of said operational amplifier, said method comprising the step of:

providing a drive voltage in order to operate said operational amplifier intermittently by an intermittent operating means provided at an enable terminal of said operational amplifier.

8. A reference voltage generating method that comprises an operational amplifier which has an enable terminal, two resistors for determining a feedback voltage which is supplied to said operational amplifier, a transistor for deciding whether or not a route of said feedback voltage to be disconnected occurs, and a capacitor for stabilizing a reference voltage which is an output voltage of said operational amplifier, said method comprising the step of:

providing a drive voltage in order to operate said operational amplifier intermittently by an oscillator provided at an enable terminal of said operational amplifier.