Standby voltage condition for fast RF amplifier bias recovery
AssigneepSemi Corporation
InventorsPoojan Wagh, Kashish Pal
Life of this patent
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Abstract
Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are possible where the amplifier is configured to operate in at least an active mode and a standby mode. Circuital arrangements can reduce bias circuit standby current during operation in the standby mode while allowing a quick recovery to normal operating conditions of the amplifier. Biasing an input transistor of the stacked transistors can be obtained by using a replica stack circuit.
Claims19
A circuital arrangement comprising:
- a transistor stack configured to operate as an amplifier, the transistor stack comprising a plurality of stacked transistors comprising an input transistor and an output transistor;
- a biasing circuit comprising a replica circuit of the transistor stack, the biasing circuit configured to provide an input gate biasing voltage to the input transistor and to a corresponding first transistor of the replica circuit,
- wherein the circuital arrangement is configured to operate in at least an active mode for amplification of a radio frequency (RF) signal through the transistor stack, and a standby mode for a reduced power consumption of the circuital arrangement,
- wherein during operation in the active mode, the biasing circuit generates the input gate biasing voltage based on a reference current conducted through the replica circuit,
- wherein during operation in the standby mode, the biasing circuit generates the input gate biasing voltage to be substantially equal to a reference voltage coupled to a source of the input transistor and corresponding input transistor of the replica circuit,
- wherein during the active mode and the standby mode the biasing circuit generates biasing voltages to transistors of the replica circuit that are substantially equal to biasing voltages to transistors of the transistor stack, and
- wherein a voltage at a drain of a last transistor of the replica circuit in correspondence of the output transistor during operation in the active mode is substantially equal to a voltage at the drain of said transistor during operation in the standby mode.
A method for biasing a transistor stack configured to operate as an amplifier using a replica circuit of the transistor stack, the method comprising:
- during an active amplification mode of the amplifier:
- regulating a biasing voltage to an input transistor of the transistor stack by conducting a reference current through the replica circuit;
- and
- providing biasing voltages to transistors of the replica circuit that are substantially equal to biasing voltages provided to transistors of the transistor stack;
- and
- during a standby mode of the amplifier:
- setting the biasing voltage to the input transistor to a fixed value that is substantially equal to a reference voltage coupled to a source of the input transistor and corresponding input transistor of the replica circuit;
- and
- providing biasing voltages to the transistors of the replica circuit that are substantially equal to biasing voltages provided to the transistors of the transistor stack,
- wherein a voltage at a drain of a last transistor of the replica circuit in correspondence of an output transistor of the transistor stack during operation in the active mode is substantially equal to a voltage at the drain of said last transistor during operation in the standby mode.
Dependencies are inferred from the claim text.