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US 5,394,028 AGranted
Apparatus for transitioning between power supply levels
AssigneeMotorola, Inc.
InventorsJames R. Feddeler, Kenneth R. Burch
Life of this patent
Estimating the term…
Abstract
A method and apparatus for transitioning between power supply levels. In one form, the present invention uses a circuit (22) in a data processing system (10) to smoothly and gradually transition a Power Output signal from a first power supply level to a second power supply level during operation. This transition from a first power supply level to a second power supply level must be smooth and gradual so that a circuit, such as oscillator circuit (12), which is receiving its power from Power Output, may continue to function properly during the transition. A Control signal, which can change back and forth between a first logic level and a second logic level, is used to select which power supply level will be provided as the Power Output.
Claims19
A circuit for transitioning between power supply levels, comprising:
- a first input power supply terminal for receiving a first power supply level;
- a second input power supply terminal for receiving a second power supply level;
- a third input power supply terminal for receiving a third power supply level;
- an output power supply terminal for providing primary power to operate a target circuit;
- a control signal;
- a control means for receiving said control signal and for determining, based upon said control signal, which one of said first and second input power supply levels to provide at said output power supply terminal;
- and
- a circuit means for smoothly and gradually transitioning from providing said first input power supply level to providing said second input power supply level at said output power supply terminal, said circuit means transitioning in response to said control means, said circuit means being coupled to said first input power supply terminal, said second input power supply terminal, said third input power supply terminal, said output power supply terminal, and said control means.
5 more elements
A data processing system, comprising:
- a target circuit;
- and
- a circuit for transitioning between power supply levels;
- and wherein said circuit for transitioning between power supply levels comprises:
- a first input power supply terminal for receiving a first power supply level;
- a second input power supply terminal for receiving a second power supply level;
- a third input power supply terminal for receiving a third power supply level;
- an output power supply terminal for providing an output power supply level, said output power supply terminal providing primary power to operate said target circuit, said output power supply terminal being coupled to said target circuit;
- a control signal which is capable of changing back and forth between a first logic level and a second logic level;
- a control means for receiving said control signal and for determining, based upon said control signal, which one of said first and second input power supply levels to provide at said output power supply terminal;
- and
- a circuit means for smoothly and gradually transitioning from providing said first input power supply level to providing said second input power supply level at said output power supply terminal, said circuit means transitioning in response to said control means, said circuit means being coupled to said first input power supply terminal, said second input power supply terminal, said third input power supply terminal, said output power supply terminal, and said control means.
9 more elements
A data processing system, comprising:
- a target circuit;
- and
- a circuit for transitioning between power supply levels;
- and wherein said circuit for transitioning between power supply levels comprises:
- a first input power supply terminal for receiving a first power supply level;
- a second input power supply terminal for receiving a second power supply level;
- a third input power supply terminal for receiving a third power supply level;
- an output power supply terminal for providing an output power supply level, said output power supply terminal providing primary power to operate said target circuit, said output power supply terminal being coupled to said target circuit;
- a control signal;
- a control means for receiving said control signal and for determining, based upon said control signal, which one of said first and second input power supply levels to provide at said output power supply terminal;
- and
- a circuit means for smoothly and gradually transitioning from providing said first input power supply level to providing said second input power supply level at said output power supply terminal, said circuit means being capable of subsequently transitioning back to providing said first input power supply level at said output power supply terminal, said circuit means transitioning in response to said control means, said circuit means being coupled to said first input power supply terminal, said second input power supply terminal, said third input power supply terminal, said output power supply terminal, and said control means.
9 more elements
Dependencies are inferred from the claim text.