Stacked PA power control
First Claim
1. A circuital arrangement comprising:
- a stack of a plurality of transistors arranged in a cascode configuration, comprising;
(i) an input transistor adapted to receive an input radio frequency (RF) signal; and
(ii) one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor adapted to output, at an adjustable output power, an output RF signal based on the input RF signal;
a first resistor tree comprising a plurality of series connected resistors; and
a low dropout (LDO) regulator coupled to the first resistor tree,wherein;
the adjustable output power is controlled by varying at least one gate voltage of the one or more cascoded transistors of the stack,a node of the first resistor tree is configured to provide the at least one gate voltage, anda control voltage to the LDO regulator varies the at least one gate voltage to provide the adjustable output power from the stack.
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Accused Products
Abstract
Systems, methods and apparatus for efficient power control of an RF amplifier for amplification of a constant envelope RF signal are described. A reduction in a size of a pass device of an LDO regulator is obtained by removing the pass device of the LDO regulator from a main current conduction path of the RF amplifier. Power control is provided by varying one or more gate voltages to cascoded transistors of a transistor stack of the RF amplifier according to a power control voltage. Various configurations for controlling the gate voltages are presented by way of a smaller size LDO regulator or by completely removing the LDO regulator. In a case where a supply voltage to the transistor stack varies, such as in a case of a battery, a compensation circuit is used to adjust the power control voltage in view of a variation of the supply voltage, and therefore null a corresponding drift in output power of the RF amplifier.
211 Citations
30 Claims
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1. A circuital arrangement comprising:
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a stack of a plurality of transistors arranged in a cascode configuration, comprising; (i) an input transistor adapted to receive an input radio frequency (RF) signal; and (ii) one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor adapted to output, at an adjustable output power, an output RF signal based on the input RF signal; a first resistor tree comprising a plurality of series connected resistors; and a low dropout (LDO) regulator coupled to the first resistor tree, wherein; the adjustable output power is controlled by varying at least one gate voltage of the one or more cascoded transistors of the stack, a node of the first resistor tree is configured to provide the at least one gate voltage, and a control voltage to the LDO regulator varies the at least one gate voltage to provide the adjustable output power from the stack. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 15, 16, 17, 18, 19, 20, 21, 22)
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9. A circuital arrangement comprising:
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a stack of a plurality of transistors arranged in a cascode configuration, comprising; (i) an input transistor adapted to receive an input radio frequency (RF) signal; and (ii) one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor adapted to output, at an adjustable output power, an output RF signal based on the input RF signal; and a gate voltage control module coupled to gates of the one or more transistors of the stack, wherein; the adjustable output power is controlled by varying at least one gate voltage of the one or more cascoded transistors of the stack, and the gate voltage control module is configured to provide, based on a control voltage, the at least one gate voltage independently from remaining gate voltages of the one or more transistors of the cascoded transistors of the stack. - View Dependent Claims (10, 11, 12, 13, 14)
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23. A method for controlling an output power of an amplifier arrangement, the method comprising:
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providing a stack of a plurality of transistors arranged in a cascode configuration, comprising an input transistor and one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor; providing a first resistor tree comprising a plurality of series connected resistors and a low dropout (LDO) regulator coupled to the first resistor tree; supplying a supply voltage across the stack; providing gate voltages to the one or more cascoded transistors; inputting a constant envelope radio frequency (RF) signal to the input transistor; based on the inputting, obtaining an amplified RF signal at the output transistor; varying at least one gate voltage of the gate voltages to the one or more cascoded transistors; and based on the varying, controlling the output power of the amplified RF signal, wherein a node of the first resistor tree is configured to provide the at least one gate voltage, and wherein a control voltage to the LDO regulator varies the at least one gate voltage for controlling of the output power of the amplified RF signal. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification