Constant vgs switch
AssigneeFairchild Semiconductor Corporation
InventorKenneth P. Snowdon
Life of this patent
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Abstract
This document discusses, among other things, a signal switch circuit including a first field effect transistor (FET) configured to couple a first node to a second node in an on-state and a charge pump circuit configured to provide a first supply voltage to control the FET, wherein a reference voltage of the charge pump circuit is coupled to a well of the FET to maintain a constant gate to source voltage of the FET during the on-state.
Claims20
A switch circuit defining an on-state and an off-state, the switch circuit, when in an on-state, couples a first node to a second node and, when in the off-state, isolates the first node from the second node, the switch circuit comprising:
- a first field effect transistor (FET) configured to couple the first node to the second node in the on-state;
- a power supply configured to provide a first supply voltage to control the FET;
- and
- wherein a reference voltage of the power supply is coupled to a well of the FET to maintain a constant gate to source voltage of the FET during the on-state.
A method for operating a switch circuit that includes an on-state and an off-state, the switch circuit, when in an on-state, couples a first node to a second node and, when in the off-state, isolates the first node from the second node, the method comprising:
- providing a first supply voltage using a charge pump;
- controlling a field effect transistor (FET) using the first supply voltage, the FET coupled between the first node and the second node;
- and
- referencing a well of the FET to a reference voltage of the charge pump to maintain a constant gate to source voltage of the FET during the on-state.
Dependencies are inferred from the claim text.