Semiconductor device and control method

Patent metadata

Field	Value
Publication number	US-9590639-B2
Application number	US-201414573813-A
Country	US
Kind code	B2
Filing date	Dec 17, 2014
Priority date	Jan 7, 2014
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A semiconductor device includes: a circuit configured to operate according to a clock; a temperature sensor configured to detect a temperature of the circuit; and a controller configured to control a frequency of the clock based on a temporal difference of power consumption of the circuit when the temperature detected by the temperature sensor exceeds a predetermined value.

First claim

What is claimed is:

1. A semiconductor device comprising:
a circuit configured to operate according to a clock;
a temperature sensor configured to detect a temperature of the circuit; and
a controller configured to
control a frequency of the clock based on a temporal difference of power consumption of the circuit when the temperature detected by the temperature sensor exceeds a predetermined value,
calculate an exponential moving average of power from acquired power values based on a variation of the power value up to this time and an elapsed time until this time, and
control the frequency of the clock based on a temporal difference of the exponential moving average.

2. The semiconductor device according to claim 1 , wherein
the controller is further configured to control a power supply voltage along with the clock frequency and change the clock frequency and the power supply voltage based on temporal difference of the exponential moving average when the temperature detected by the temperature sensor exceeds a predetermined upper limit.

3. The semiconductor device according to claim 2 , wherein
the predetermined upper limit is set so that the predetermined upper limit becomes largest in a range not exceeding a temperature limit even when power consumption of the semiconductor device becomes maximum power consumption.

4. The semiconductor device according to claim 1 , wherein
the controller is further configured to change the clock frequency based on the variation of the power value when the temperature detected by the temperature sensor falls below a predetermined lower limit.

5. A control method of a clock frequency of a semiconductor device including circuits that operates according to a clock, the control method comprising:
detecting a temperature of the circuits;
monitoring power consumption of the circuits;
calculating a temporal difference of the monitored power consumption;
changing the clock frequency based on the temporal difference of the power consumption when the detected temperature exceeds a predetermined upper limit;
calculating an exponential moving average of power from acquired power values based on a variation of the power value up to this time and an elapsed time until this time; and
controlling the clock frequency based on a temporal difference of the exponential moving average.

Assignees

• Fujitsu Ltd

Inventors

• Kawabe Yukihito
• Hara Michiharu

Classifications

• G05F1/463 Primary

  Sources providing an output which depends on temperature · CPC title

• H03L1/00

  Stabilisation of generator output against variations of physical values, e.g. power supply · CPC title

• G06F1/206

  comprising thermal management · CPC title

• H03L7/06

  using a reference signal applied to a frequency- or phase-locked loop · CPC title

• H03L7/00 Primary

  Automatic control of frequency or phase; Synchronisation · CPC title