Wideband class-S modulator and method therefor
First Claim
Patent Images
1. A class-S modulator for amplifying an input signal having envelope information, comprising:
- a comparator having a first input to receive said input signal, a second input to receive a reference waveform, and differential compared outputs;
a differential level shifter having inputs coupled to said differential compared outputs of said comparator, and level shifted outputs;
a driver including at least one input coupled to said level shifted outputs, a first differential output, and a second differential output;
a switching stage including a high-side switch controlled by said first differential output, and a low-side switch controlled by said second differential output, said high-side and said low-side switches being configured in a totem-pole arrangement to generate a switch output; and
a low-pass filter coupled to said switch output to restore an amplified envelope of said input signal.
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Abstract
A class-S modulator (5) receives an input signal (10) having envelope information and pulse-width modulates the input signal (10) using a reference waveform (26) from a waveform generator (25). The envelope becomes a pulse-width modulated signal is level-shifted and amplified through a pre-driver (40). A driver (50) controls switches (60, 70) which drive an output (80) into a low-pass filter (90) wherein the envelope is restored to the amplified signal for driving a power amplifier in a wide-band transceiver.
38 Citations
18 Claims
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1. A class-S modulator for amplifying an input signal having envelope information, comprising:
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a comparator having a first input to receive said input signal, a second input to receive a reference waveform, and differential compared outputs; a differential level shifter having inputs coupled to said differential compared outputs of said comparator, and level shifted outputs; a driver including at least one input coupled to said level shifted outputs, a first differential output, and a second differential output; a switching stage including a high-side switch controlled by said first differential output, and a low-side switch controlled by said second differential output, said high-side and said low-side switches being configured in a totem-pole arrangement to generate a switch output; and a low-pass filter coupled to said switch output to restore an amplified envelope of said input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An amplifier for amplifying an input signal by eliminating an envelope of said input signal and then restoring said envelope to an output signal, said amplifier comprising:
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a comparator having a first input to receive said input signal, a second input to receive a reference waveform, and differential compared outputs; a differential level shifter having inputs coupled to said differential compared outputs of said comparator, and level shifted outputs; a driver including at least one input coupled to said level shifted outputs, a first differential output, and a second differential output; a switching stage including a high-side switch controlled by said first differential output, and a low-side switch controlled by said second differential output, said high-side and said low-side switches being configured in a totem-pole arrangement to generate a switch output; and a low-pass filter coupled to said switch output to restore an amplified envelope of said input signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for amplifying an input signal having envelope information, said method comprising the steps of:
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comparing said input signal to be amplified with a reference waveform; generating differential compared output signals from said input signal and said reference waveform; level shifting said differential compared output signals to produce level shifted outPut signals; driving at least one switch with said level shifted output signals; said at least one switch generating a switch output from said compared output signal; and low-pass filtering said switch output to restore said envelope. - View Dependent Claims (16, 17, 18)
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Specification