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US 2006/0232318 A1Published application
Power clamp circuit and semiconductor device
AssigneeFujitsu Limited
InventorsJunji Iwahori, Teruo Suzuki, Kenji Hashimoto, Noriaki Saito
Life of this patent
Estimating the term…
Abstract
A power clamp circuit for preventing unnecessary power supply leak current at a tolerable power supply noise level. A reference voltage circuit generates a reference voltage by reducing a positive voltage supplied from a first power supply terminal by a predetermined potential and supplies the reference voltage to a buffer circuit. The buffer circuit activates a transistor functioning as a clamp element based on the reference voltage to short-circuit the first and second power supply terminals.
Claims18
A power clamp circuit comprising:
- an RC circuit including a resistor and a capacitor connected in series between a first power supply terminal, for supplying a first power supply voltage functioning as a positive voltage, and a second power supply terminal, for supplying a second power supply voltage functioning as a negative voltage;
- a clamp element connected between the first and second power supply terminals so as to become conductive or non-conductive in response to an input signal to selectively cause short-circuiting between the first and second power supply terminals;
- a buffer circuit for generating the input signal provided to the clamp element based on a potential at a node between the resistor and the capacitor and a reference voltage;
- and
- a reference voltage circuit, connected to the buffer circuit, for generating the reference voltage by reducing the first power supply voltage by a predetermined potential or by raising the second power supply voltage by a predetermined potential and providing the reference voltage to the buffer circuit.
2 more elements
A semiconductor device comprising:
- an internal circuit;
- and
- a power clamp circuit connected to the internal circuit, the power clamp circuit including:
- an RC circuit including a resistor and a capacitor connected in series between a first power supply terminal, for supplying a first power supply voltage functioning as a positive voltage, and a second power supply terminal, for supplying a second power supply voltage functioning as a negative voltage;
- a clamp element connected between the first and second power supply terminals so as to become conductive or non-conductive in response to an input signal to selectively cause short-circuiting between the first and second power supply terminals;
- a buffer circuit for generating the input signal provided to the clamp element based on a potential at a node between the resistor and the capacitor and a reference voltage;
- and
- a reference voltage circuit, connected to the buffer circuit, for generating the reference voltage by reducing the first power supply voltage by a predetermined potential or by raising the second power supply voltage by a predetermined potential and providing the reference voltage to the buffer circuit.
5 more elements
Dependencies are inferred from the claim text.