Apparatus and methods power amplifier biasing
First Claim
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1. A mobile device comprising:
- a transceiver configured to generate a radio frequency signal and an enable signal having an enabled state and a disabled state;
a power amplifier configured to amplify the radio frequency signal; and
a bias circuit configured to receive the enable signal and to generate a bias current that biases the power amplifier, the bias circuit configured to control a magnitude of the bias current based on the enable signal and to provide a transient boost to the magnitude of the bias current when the enable signal is transitioned from the disabled state to the enabled state to compensate for a variation in gain of the power amplifier from thermal effects, the bias circuit including a gain correction circuit having an input that receives the enable signal and an output that generates a correction current, a first bipolar transistor having an emitter electrically connected to the output of the correction circuit, and a second bipolar transistor having a base electrically connected to a base of the first bipolar transistor and an emitter configured to generate the bias current.
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Abstract
Apparatus and methods for biasing a power amplifier are disclosed. In one embodiment, a method of biasing a power amplifier includes shaping an enable signal using a time-dependent signal generator to generate a control current, amplifying the control current using a current amplifier to generate a correction current, and generating a bias current for a power amplifier using a primary biasing circuit. The primary biasing circuit is configured to use the correction current to correct for a variation in gain of the power amplifier when the power amplifier is enabled.
42 Citations
20 Claims
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1. A mobile device comprising:
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a transceiver configured to generate a radio frequency signal and an enable signal having an enabled state and a disabled state; a power amplifier configured to amplify the radio frequency signal; and a bias circuit configured to receive the enable signal and to generate a bias current that biases the power amplifier, the bias circuit configured to control a magnitude of the bias current based on the enable signal and to provide a transient boost to the magnitude of the bias current when the enable signal is transitioned from the disabled state to the enabled state to compensate for a variation in gain of the power amplifier from thermal effects, the bias circuit including a gain correction circuit having an input that receives the enable signal and an output that generates a correction current, a first bipolar transistor having an emitter electrically connected to the output of the correction circuit, and a second bipolar transistor having a base electrically connected to a base of the first bipolar transistor and an emitter configured to generate the bias current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of power amplifier biasing in a mobile device, the method comprising:
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generating a radio frequency signal and an enable signal using a transceiver; amplifying the radio frequency signal using a power amplifier; biasing the power amplifier with a bias current from a bias circuit; generating a correction current based on the enable signal using a gain correction circuit of the bias circuit; providing the correction current to an emitter of a first bipolar transistor of the bias circuit; generating the bias circuit at an emitter of a second bipolar transistor of the bias circuit, the second bipolar transistor having a base electrically connected to a base of the first bipolar transistor; transitioning the enable signal from a disabled state to an enabled state; and using the bias circuit to provide a transient boost to a magnitude of the bias current in response to the transition to compensate for a variation in gain of the power amplifier from thermal effects. - View Dependent Claims (14)
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15. A power amplifier system comprising:
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a power amplifier configured to amplify a radio frequency signal, the power amplifier including a bias input that receives a bias current; and a bias circuit configured to receive an enable signal having an enabled state and a disabled state, the bias circuit configured to control a magnitude of the bias current based on the enable signal and to provide a transient boost to the magnitude of the bias current when the enable signal is transitioned from the disabled state to the enabled state to compensate for a variation in gain of the power amplifier from thermal effects, the bias circuit including a gain correction circuit having an input that receives the enable signal and an output that generates a correction current, a first bipolar transistor having an emitter electrically connected to the output of the correction circuit, and a second bipolar transistor having a base electrically connected to a base of the first bipolar transistor and an emitter configured to generate the bias current. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification