Voltage detecting circuit and information processing apparatus
AssigneeFujitsu Limited
InventorAtsushi Mori
Life of this patent
Estimating the term…
Abstract
A ring oscillator included in a reference-frequency generating circuit and a comparative-frequency generating circuit has multiple inverters that are arranged in series in a ring shape. A sampling unit acquires an output signal from the respective inverters in each sampling cycle. A transition-stage calculating unit calculates the number of transition stages that is the number of inverters in which a value of an output signal has changed during the sampling cycle of each ring oscillator based on the output signal of each sampling cycle acquired by the sampling unit. A voltage detecting unit performs voltage detection based on the number of transition stages acquired by the transition-stage calculating unit.
Claims5
A voltage detection circuit comprising:
- a first ring oscillator and a second ring oscillator that have a plurality of inverters arranged in series in a ring shape;
- a sampling unit that acquires, for each of the first ring oscillator and the second ring oscillator, a respective output signal that is output from each of the inverters on a per clock basis by following a system clock in each sampling cycle identical to a cycle of the system clock, the respective output signal including a respective first output signal in a first sampling cycle and a respective second output signal in a second sampling cycle that is one cycle previous to the first sampling cycle;
- a transition-stage calculating unit that calculates:
- a first number of transition stages that is a number of the inverters in which a value of an output signal has transitioned during the sampling cycle, based on the respective first output signal and the respective second output signal acquired for the first ring oscillator, and
- a second number of transition stages, based on the respective first output signal and the respective second output signal acquired for the second ring oscillator;
- and
- a voltage detecting unit that performs voltage detection based on the number of transition stages acquired by the transition-stage calculating unit.
An information processing apparatus comprising:
- a voltage detection circuit;
- a voltage control circuit;
- and
- a processor,
- the voltage detection circuit includes
- a first ring oscillator and a second ring oscillator that have a plurality of inverters arranged in series in a ring shape;
- a sampling unit that acquires, for each of the first ring oscillator and the second ring oscillator, a respective output signal that is output from each of the inverters on a per clock basis by following a system clock in each sampling cycle identical to a cycle of the system clock, the respective output signal including a respective first output signal in a first sampling cycle and a respective second output signal in a second sampling cycle that is one cycle previous to the first sampling cycle;
- a transition-stage calculating unit that calculates:
- a first number of transition stages that is a number of the inverters in which a value of an output signal has transitioned during the sampling cycle, based on the respective first output signal and the respective second output signal acquired for the first ring oscillator, and
- a second number of transition stages, based on the respective first output signal and the respective second output signal acquired for the second ring oscillator;
- and
- a voltage detecting unit that performs voltage detection based on the number of transition stages acquired by the transition-stage calculating unit,
- the voltage control circuit controls a voltage to be output to the processor based on a voltage detected by the voltage detection circuit, and applies the voltage output to the processor to one of the ring oscillators, and
- the processor operates, receiving input of the voltage controlled by the voltage control circuit.
Dependencies are inferred from the claim text.