US 7,065,668 B2Granted

Apparatus for selecting and outputting either a first clock signal or a second clock signal

AssigneeSeiko Epson Corporation

InventorsTsukasa Kosuda, Motomu Hayakawa

Life of this patent

Estimating the term…

Abstract

By using a CR oscillating circuit and a PLL oscillating circuit selectively, these two oscillating circuits are used as a high frequency, low power consumption, short waiting time for stable oscillation, and low operating voltage oscillating circuit.

Claims9

Dependent claims

An information processing apparatus comprising:

a first oscillating circuit that generates a first clock signal by oscillation and has a first oscillation stability time, the first oscillation stability time being a time required for frequency of the first clock signal becoming stable from the start of the oscillation, the first oscillating circuit being capable of operating with a power supply voltage equal to or higher than a first minimum operating voltage that is a minimum voltage required for operation of the first oscillating circuit;
a second oscillating circuit that generates a second clock signal by oscillation and has a second oscillation stability time, the second oscillation stability time being a time required for frequency of the second clock signal becoming stable from the start of the oscillation, and being longer than the first oscillation stability time, the second oscillating circuit being capable of operating with a power supply voltage equal to or higher than a second minimum operating voltage that is higher than the first minimum operating voltage;
a power supply voltage measuring circuit that measures power supply voltage;
a switching circuit for, as long as the voltage measured by the power supply voltage measuring circuit is not higher than the second minimum operating voltage, selecting and outputting either the first clock signal or the second clock signal as the clock signal based on an elapsed time of the first oscillating circuit from the start of the oscillation and an elapsed time of the second oscillating circuit from the start of the oscillation, and as long as the voltage measured by the power supply voltage measuring circuit is higher than the second minimum operating voltage, selecting and outputting the second clock signal as a clock signal without considering an elapsed time of the first oscillating circuit;
and
an information processing unit for, in synchronism with the clock signal, performing information processing.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/936,986Filed 9 Sep 2004 · division
Priority: JP 2000-10012231 Mar 2000
Published: US 2005/0030112 A110 Feb 2005
Granted: 20 Jun 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G06F 3/0317
Detection arrangements using opto-electronic means: in co-operation with a patterned surface, e.g. absolute position or relative movement…
G06F 1/06
Generating or distributing clock signals or signals derived directly therefrom: clock generators producing several clock signals
G06F 1/08
Generating or distributing clock signals or signals derived directly therefrom: clock generators with changeable or programmable clock frequency
G06F 1/163
For portable computers: wearable computers, e.g. on a belt

Family

Application09/823,137Parent of this division · filed 29 Mar 2001
US 2005/0030112 A1Pre-grant publication · published 10 Feb 2005
US 2003/0070106 A1Published application
US 7,065,668 B2This patent

From the US filing history. Foreign family members aren’t listed.

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Abstract

An information processing apparatus comprising:

a first oscillating circuit that generates a first clock signal by oscillation and has a first oscillation stability time, the first oscillation stability time being a time required for frequency of the first clock signal becoming stable from the start of the oscillation, the first oscillating circuit being capable of operating with a power supply voltage equal to or higher than a first minimum operating voltage that is a minimum voltage required for operation of the first oscillating circuit;
a second oscillating circuit that generates a second clock signal by oscillation and has a second oscillation stability time, the second oscillation stability time being a time required for frequency of the second clock signal becoming stable from the start of the oscillation, and being longer than the first oscillation stability time, the second oscillating circuit being capable of operating with a power supply voltage equal to or higher than a second minimum operating voltage that is higher than the first minimum operating voltage;
a power supply voltage measuring circuit that measures power supply voltage;
a switching circuit for, as long as the voltage measured by the power supply voltage measuring circuit is not higher than the second minimum operating voltage, selecting and outputting either the first clock signal or the second clock signal as the clock signal based on an elapsed time of the first oscillating circuit from the start of the oscillation and an elapsed time of the second oscillating circuit from the start of the oscillation, and as long as the voltage measured by the power supply voltage measuring circuit is higher than the second minimum operating voltage, selecting and outputting the second clock signal as a clock signal without considering an elapsed time of the first oscillating circuit;
and
an information processing unit for, in synchronism with the clock signal, performing information processing.

3 more elements

Facts

Application

10/936,986Filed 9 Sep 2004 · division

Priority

JP 2000-10012231 Mar 2000

Published

US 2005/0030112 A110 Feb 2005

Granted

20 Jun 2006

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

G06F 3/0317
Detection arrangements using opto-electronic means: in co-operation with a patterned surface, e.g. absolute position or relative movement…
G06F 1/06
Generating or distributing clock signals or signals derived directly therefrom: clock generators producing several clock signals
G06F 1/08
Generating or distributing clock signals or signals derived directly therefrom: clock generators with changeable or programmable clock frequency
G06F 1/163
For portable computers: wearable computers, e.g. on a belt