High-Speed Current Switching
AssigneeSasken Communication Technologies Limited
InventorsK R Srinidhi Koushik, Lavanya M. Nirikhi, Katragadda Anandaram, Santosh M. Narawade
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Abstract
A method and circuit for high-speed current switching includes altering the operating voltage of the Current Source using a resistor in non-transmission mode, turning parasitic capacitive coupling into an advantage for faster settling of CS gate bias voltage. The resistor is designed to compensate for the voltage coupling when the Current Source is switched to Transmit mode. This greatly improves the settling time of current and bias voltage of the Current Source transistor without adding any complex circuit and saves 100% of power consumed in non-transmit mode.
Claims30
A high-speed current switching circuit comprising of a first Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) acting as a resistive element, a second MOSFET acting as a Current source/sink, a third MOSFET acting as a Current Mirroring element and a plurality of transistors and resistors wherein
- a drain terminal of said first MOSFET is connected to gate terminals of said second and third MOSFETs and drain terminal of third MOSFET;
- a gate terminal of said first MOSFET is connected to a control signal;
- and
- a source terminal of said first MOSFET is connected to the drain terminal of said second MOSFET.
A high-speed current switching circuit comprising of a first resistor, a first Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) acting as a switch, a second MOSFET acting as a Current source/sink, a third MOSFET acting as a Current Mirroring element and a plurality of resistors wherein
- one terminal of said first resistor is connected to a drain of said first MOSFET;
- other terminal of said first resistor is connected to gate terminals of said second and third MOSFETs and drain terminal of said third MOSFET;
- a gate terminal of said first MOSFET is connected to a control signal;
- and
- a source terminal of said first MOSFET is connected to the drain terminal of the said second MOSFET.
A high-speed current switching circuit comprising of a first resistor, a first Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) acting as a switch, a second MOSFET acting as a Current source/sink, a third MOSFET acting as a Current Mirroring element, a fourth MOSFET and a plurality of resistors wherein
- one terminal of said first resistor is connected to the drain terminal of said first MOSFET;
- the other terminal of said first resistor is connected to gate terminals of the said second and third MOSFETs and drain terminal of third MOSFET;
- a gate terminal of said first MOSFET is connected to a control signal;
- a source terminal of said first MOSFET is connected to the drain terminal of said second MOSFET;
- a source terminal of said fourth MOSFET is connected to drain terminal of said second MOSFET;
- a gate terminal of said fourth MOSFET is connected to a logical invert of said control signal;
- and
- a drain terminal of said fourth MOSFET is connected to drain terminals of at least two MOSFETs whose source terminals are connected to termination resistors.
A method to enable high-speed current switching, said method comprising steps of:
- a control signal turning a first MOSFET on when a Current source/sink is not sourcing the full current;
- said first MOSFET raising gate voltage of said Current source/sink, wherein raise/dip in said gate voltage compensates for the dip/raise in said gate voltage due to coupling between said gate and drain of said current source/sink when said current source/sink starts sourcing/sinking the full current.
Dependencies are inferred from the claim text.