US 6,205,079 B1Granted

Semiconductor integrated circuit having power-supply circuits for producing internal supply voltages

AssigneeKabushiki Kaisha Toshiba

InventorToshimasa Namekawa

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Abstract

A semiconductor integrated circuit comprises a first internal power supply circuit for producing a first internal supply voltage, a clamp circuit for short-circuiting an output node of the first internal power supply circuit and a first external power supply node, a power-on sensing circuit for, upon detecting a second external supply voltage having reached a specified value, producing a first control signal, a second internal power supply circuit responsive to the second external supply voltage for producing a second internal supply voltage, and a potential detecting circuit for, upon detecting the second internal supply voltage having reached a specified value, producing a second control signal. The clamp circuit is enabled by the first control signal from the power-on sensing circuit to short-circuit the first internal power supply node and the first external power supply node and disabled by the second control signal from the potential detecting circuit from short-circuiting, thereby allowing the first internal power supply circuit to produce the first internal supply voltage.

Claims20

Dependent claims

A semiconductor integrated circuit comprising:

a first node for receiving a first voltage which is externally supplied;
a second node for receiving a second voltage that differs in magnitude from the first voltage;
a first internal power supply circuit responsive to at least the second voltage on the second node for producing a first internal supply voltage that differs in magnitude from the first voltage;
a first voltage detecting circuit connected to receive the second voltage from the second node for, upon detecting that the magnitude of the voltage on the second node has reached a first specified value, producing a first detect signal;
a second internal power supply circuit responsive to at least the second voltage on the second node for producing a second internal supply voltage that differs in magnitude from the second voltage;
a second voltage detecting circuit connected to receive the second internal supply voltage from the second internal power supply circuit for, upon detecting that the magnitude of the second internal supply voltage has reached a second specified value, producing a second detect signal which causes the first internal power supply circuit to start producing the first internal supply voltage;
and
a clamp circuit coupled to an output of the first internal power supply circuit and the first node for, upon receiving the second detect signal, releasing a short-circuited state of the output of the first internal power supply circuit and the first node.

5 more elements

A semiconductor integrated circuit comprising:

a first node for receiving a first voltage which is externally supplied;
a second node for receiving a second voltage that differs in magnitude from the first voltage;
a first internal power supply circuit responsive to at least the second voltage on the second node for producing a first internal supply voltage that differs in magnitude from the first voltage;
a first voltage detecting circuit connected to receive the second voltage from the second node for, upon detecting that the magnitude of the voltage on the second node has reached a first specified value, producing a first detect signal;
a second internal power supply circuit responsive to at least the second voltage on the second node for producing a second internal supply voltage that differs in magnitude from the second voltage;
a second voltage detecting circuit connected to receive the first internal supply voltage from the first internal power supply circuit for, upon detecting that the magnitude of the first internal supply voltage has reached a second specified value, producing a second detect signal which causes the second internal power supply circuit to start producing the second internal supply voltage;
and
a clamp circuit coupled to an output of the second internal power supply circuit and the first node for, upon receiving the second detect signal, releasing a short-circuited state of the output of the second internal power supply circuit and the first node.

5 more elements

Dependencies are inferred from the claim text.