Automatic bias controller for a pulsed power amplifier
First Claim
1. A system comprising:
- a power amplifier characterized by an associated quiescent current value;
a measurement circuit configured to measure a power supply current provided to the power amplifier, wherein the measurement circuit comprises a current transformer configured to convert the measured power supply current to a measured voltage;
a comparison circuit configured to compare the measured power supply current to the quiescent current value; and
a bias controller coupled to the comparison circuit, the bias controller configured to adjust a bias signal provided to the power amplifier based on the comparison, wherein the bias signal is adjusted between pulses for use with a next pulse.
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Accused Products
Abstract
Systems and methods for automatically controlling the bias in a pulsed power amplifier include components for measuring the current in an amplifier, comparing the measured value with the desired value, modifying the bias, and controlling the bias applied to the power amplifier. A measurement circuit converts the measured current to a voltage, and a comparator compares a measured voltage with a reference voltage to continuously indicate whether the amplifier current is less than a desired quiescent value. A circuit controls the level of the gate-bias (Vg) during a pulse, such as with a pulse width modulator. The measurement of the amplifier current is registered after the bias is enabled, but before the signal pulse. Drive control logic implements a control algorithm for adjusting the gate value in between pulses and in time to be used for the next pulse.
8 Citations
20 Claims
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1. A system comprising:
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a power amplifier characterized by an associated quiescent current value; a measurement circuit configured to measure a power supply current provided to the power amplifier, wherein the measurement circuit comprises a current transformer configured to convert the measured power supply current to a measured voltage; a comparison circuit configured to compare the measured power supply current to the quiescent current value; and a bias controller coupled to the comparison circuit, the bias controller configured to adjust a bias signal provided to the power amplifier based on the comparison, wherein the bias signal is adjusted between pulses for use with a next pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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determining a quiescent current value of a power amplifier; measuring a power supply current supplied to the power amplifier by converting the power supply current to a measured voltage using a current transformer; comparing the measured current to the quiescent current value; and adjusting a bias of the power amplifier based on the comparison. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A system comprising:
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a power amplifier characterized by an associated quiescent current value; a measurement circuit configured to measure a power supply current provided to the power amplifier, wherein the measurement circuit comprises a current transformer configured to convert the measured power supply current to a measured voltage; a comparison circuit configured to compare the measured power supply current to the quiescent current value; digital circuitry coupled to the comparison circuit and configured to adjust a bias signal applied to the power amplifier using based on the output of the comparison circuit; and a gate control circuit configured to provide the bias signal to the power amplifier according to control signals provided by the digital circuitry. - View Dependent Claims (17, 18, 19, 20)
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Specification