IC device having a transistor switch for a power supply
AssigneeRohm Co., Ltd.
InventorYoshikazu Fujimori
Life of this patent
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Abstract
An IC device has a MOSFET serving as a power switch, a condenser connected between a first input terminal of the IC and the gate of the MOSFET, and a ferroelectric condenser connected between a second input terminal of the IC and the gate of the MOSFET. A prescribed voltage having a predetermined polarity is applied across the first and the second input terminals to generate a remanent polarization oriented in a specific direction in the ferroelectric condenser, thereby raising the threshold voltage of the MOSFET to a higher level than its original level. The power switching MOSFET is fabricated in the same manufacturing process as for other circuit blocks of the IC device such that it has substantially the same threshold voltage as that of the MOSFETs in other circuit blocks.
Claims13
A semiconductor integrated circuit device including at least one transistor circuit block and at least one power supply transistor for supplying said block with power, wherein
- said power supply transistor is a metal insulator field effect transistor;
- said IC device further comprises a condenser having one end connected to the gate of said power supplying MISFET and a ferroelectric condenser having one end connected to the gate of said power supplying MISFET;
- said transistor circuit block is a transistor including a MISFET and is supplied with power via said power supplying MISFET;
- said power supplying MISFET and said MISFET of said transistor circuit block are fabricated together in said IC device such that said power supplying MISFET and said MISFET of said transistor circuit block have substantially the same threshold voltage.
An IC device, comprising:
- a first power supplying transistor switch circuit including
- a power supplying P-type MISFET,
- a first condenser having one end connected to the gate of said power supplying P-type MISFET, and
- a first ferroelectric condenser having one end connected to the gate of said power supplying P-type MISFET;
- a transistor circuit block including MISFETs;
- and
- a second power supplying transistor switch circuit including
- a power supplying N-type MISFET,
- a second condenser having one end connected to the gate of said power supplying N-type MISFET, and
- a second ferroelectric condenser having one end connected to the gate of said power supplying N-type MISFET, wherein
- said first power supplying transistor switch circuit, transistor circuit block, and second power supplying transistor switch circuit are connected in series in the order mentioned to provide power to said transistor circuit block via said first and second power supplying MISFETs,
- said first and second power supplying MISFETs and said MISFET of said transistor circuit block are fabricated together in said IC device, thereby rendering the threshold voltages of said first and second power supplying MISFETs substantially the same as the threshold voltage of said MISFET of said transistor circuit block.
A method of controlling a power supplying transistor switch circuit for supplying power to a transistor circuit block fabricated together with said power supplying transistor switch circuit in an IC device, said power supplying transistor switch circuit having substantially the same threshold voltage as said transistor circuit block, wherein
- said power supplying transistor switch circuit comprises a power supplying MISFET, a condenser having one end connected to the gate of said power supplying MISFET, and a ferroelectric condenser having one end connected to the gate of said power supplying MISFET,
- said method comprising steps of:
- applying a temporary voltage across the other end of said condenser and the other end of said ferroelectric condenser in one direction to generate remanent polarization in said ferroelectric condenser, thereby providing said power supplying MISFET with a threshold voltage higher than said threshold voltage of said transistor circuit block;
- and
- in the state where said remnant polarization occurs, keeping the other end of said ferroelectric condenser open while applying a control voltage to the other end of said condenser to turn ON/OFF said power supplying MISFET.
Dependencies are inferred from the claim text.