Ground partitioned power amplifier for stable operation
First Claim
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1. A power amplifier system comprising:
- a signal path comprising a plurality of cascaded gain stages and an output stage the input of which is coupled to the output of the last gain stage of the plurality of cascaded gain stages, wherein at least one local positive feedback loop is created in the signal path by one or more shared ground connections between one or more of the plurality of cascaded gain stages and the output stage; and
a neutralizing feedback loop configured to control at least one negative feedback loop to balance the at least one local positive feedback loop.
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Abstract
Achievement of robust stability of a power amplifier (PA) that allows the sharing of the ground between the driver stages and the output stage is shown. A controlled amount of negative feedback is used to neutralize the local positive feedback that results from the driver-to-output stage ground sharing in the signal path, for example, a radio frequency (RF) signal path. The solution keeps a strong drive and a good performance of the PA. Exemplary embodiments are shown for the PA positive feedback neutralization. A first embodiment uses a ground signal divider while another embodiment uses a ground signal divider weighting technique.
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Citations
15 Claims
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1. A power amplifier system comprising:
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a signal path comprising a plurality of cascaded gain stages and an output stage the input of which is coupled to the output of the last gain stage of the plurality of cascaded gain stages, wherein at least one local positive feedback loop is created in the signal path by one or more shared ground connections between one or more of the plurality of cascaded gain stages and the output stage; and a neutralizing feedback loop configured to control at least one negative feedback loop to balance the at least one local positive feedback loop. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A power amplifier system comprising:
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a signal path having at least one local positive feedback loop present in the signal path, wherein the local positive feedback loop is created by one or more shared ground connections in the signal path; and a neutralizing feedback loop configured to control at least one negative feedback loop to balance the at least one local positive feedback loop. - View Dependent Claims (12)
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13. A power amplifier system comprising:
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a signal path comprising a plurality of cascaded gain stages and an output stage the input of which is coupled to the output of the last gain stage of the plurality of cascaded gain stages, wherein at least one local positive feedback loop is created in the signal path by one or more cascode devices in the output stage; and a neutralizing feedback loop configured to control at least one negative feedback loop to balance the at least one local positive feedback loop. - View Dependent Claims (14, 15)
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Specification