US 7,071,768 B2Granted

Semiconductor integrated circuit having controllable internal supply voltage

AssigneeFujitsu Limited

InventorsHiroyuki Abe, Yutaka Takasuka, Hisao Ise, Hiroko Takano, Sachie Takahashi

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Abstract

In an integrated circuit having an internal supply voltage generation circuit which generates an internal supply voltage by descending an external supply voltage, there is provided an internal circuit which operates with a supplied internal supply voltage. The internal supply voltage generation circuit changes an internal supply voltage level to be generated in accordance with an operation speed of the internal circuit. Preferably the semiconductor integrated circuit includes a clock control circuit which generates an internal clock signal the frequency of which is controlled in accordance with the operation speed of the internal circuit. When the internal clock signal is controlled to have a higher frequency, the internal supply voltage is controlled to be higher. Also, when the internal clock signal is controlled to have a lower frequency, the internal supply voltage is controlled to be lower.

Claims23

Dependent claims

A semiconductor integrated circuit comprising:

an internal supply voltage generation circuit which generates an internal supply voltage by decreasing an external supply voltage;
a supply voltage monitoring circuit which monitors a level of the internal supply voltage;
a clock control circuit which generates an internal clock having a frequency controlled in accordance with an operation speed of an internal circuit and provides the generated internal clock to the internal circuit;
and
a voltage control circuit which controls the level of the internal supply voltage generated by the internal supply voltage generation circuit to become a level corresponding to the frequency of the internal clock,
wherein, the clock control circuit increases the frequency of the internal clock to a first frequency from a second frequency lower than the first frequency, after the supply voltage monitoring circuit detects the level of the internal supply voltage is increased to a level corresponding to the first frequency, and
wherein the supply voltage monitoring circuit outputs an internal reset signal when the level monitored by the supply voltage monitoring circuit becomes lower than a predetermined minimum level, so that data in a register or a memory in the internal circuit is saved in response to the internal reset signal.

4 more elements

A semiconductor integrated circuit comprising:

an internal supply voltage generation circuit which generates an internal supply voltage by decreasing an external supply voltage;
a supply voltage monitoring circuit which monitors a level of the internal supply voltage;
a clock control circuit which generates an internal clock having a frequency controlled in accordance with an operation speed of the internal circuit and provides the generated internal clock to the internal circuit;
a voltage control circuit which controls the level of the internal supply voltage generated by the internal supply voltage generation circuit to become a level corresponding to the frequency of the internal clock;
and
an external reset circuit which generates an initialization signal to restore the internal circuit from the standby mode,
wherein, the clock control circuit increases the frequency of the internal clock to a first frequency from a second frequency lower than the first frequency, after the supply voltage monitoring circuit detects the level of the internal supply voltage is increased to a level corresponding to the first frequency,
wherein, when the internal circuit is controlled to set into standby mode, the internal supply voltage generation circuit suspends generation of the internal supply voltage, and
wherein, in response to said initialization signal, the internal supply voltage generation circuit resumes generation of the internal supply voltage.

6 more elements

Dependencies are inferred from the claim text.