Time-delay compensating wideband class-s modulator and method therefor

Claim 2

A time-delay compensating class-S modulator for amplifying an input signal having envelope information to an output signal having said envelope, comprising: an error amplifier having a first input to receive said input signal, a second input, and an output for conveying a delay error signal representing a phase delay error between said input signal and said output signal; a comparator having a first input to receive said delay error signal, a second input to receive a reference waveform, and a compared output; a driver including at least one input coupled to said compared output, 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.

Claim 3

The time-delay compensating class-S modulator as recited in claim 1, wherein said comparator pulse-width modulates said delay error signal with said reference waveform.

Claim 4

The time-delay compensating class-S modulator as recited in claim 1, further comprising a feedback divider defining a closed-loop gain, said feedback divider having an input coupled to said output signal and an output coupled to said second input of said error amplifier.

Claim 5

The time-delay compensating class-S modulator as recited in claim 3, further comprising a stability compensation network coupled between said output of said feedback divider and said delay error signal.

Claim 6

The time-delay compensating class-S modulator as recited in claim 1, wherein said comparator has differential outputs.

Claim 7

The time-delay compensating class-S modulator as recited in claim 5, further comprising a differential level shifter having inputs coupled to said differential outputs of said comparator and outputs to provide compatible drive levels for said inputs of said driver.

Claim 8

The time-delay compensating class-S modulator as recited in claim 1, further comprising a waveform generator to generate said reference waveform.

Claim 9

The time-delay compensating class-S modulator as recited in claim 1, wherein said reference waveform is a triangular waveform.

Claim 10

The time-delay compensating class-S modulator as recited in claim 1, wherein said low-side switch and said high-side switch are each comprised of at least one field effect transistor.

Claim 11

An time-delay compensating 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: an error amplifier having a first input to receive said input signal, a second input, and an output for conveying a delay error signal representing a phase delay error between said input signal and said output signal; a comparator having a first input to receive said delay error signal, a second input to receive a reference waveform, and a compared output; a driver including at least one input coupled to said compared output, 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.

Claim 12

An time-delay compensating 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: an error amplifier having a first input to receive said input signal, a second input, and an output for conveying a delay error signal representing a phase delay error between said input signal and said output signal; a comparator having a first input to receive said delay error signal, a second input to receive a reference waveform, and a compared output; a driver including at least one input coupled to said compared output, 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.

Claim 13

The time-delay compensating amplifier as recited in claim 10, wherein said comparator pulse-width modulates said delay error signal with said reference waveform.

Claim 14

The time-delay compensating amplifier as recited in claim 10, further comprising a feedback divider defining a closed-loop gain, said feedback divider having an input coupled to said output signal and an output coupled to said second input of said error amplifier.

Claim 15

The time-delay compensating amplifier as recited in claim 12, further comprising a stability compensation network coupled between said output of said feedback divider and said delay error signal.

Claim 16

The time-delay compensating amplifier as recited in claim 10, wherein said reference waveform is a triangular waveform.

Claim 17

The time-delay compensating amplifier as recited in claim 10, further comprising a waveform generator to generate said reference waveform.

Claim 18

The time-delay compensating amplifier as recited in claim 10, wherein said low-side switch and said high-side switch are each comprised of at least one field effect transistor.

Claim 21

The method as recited in claim 17, wherein said comparing said input signal step comprises the steps of: dividing said output signal defining a closed-loop gain to form an attenuated output signal; and comparing said input signal with said attenuated output signal.

Claim 22

The method as recited in claim 17, wherein said generating a compared output step comprises the step of pulse-width modulating said delay error signal with said reference waveform.

Claim 23

The method as recited in claim 17, wherein said driving step further comprises a step of level shifting said differential compared output signals prior to driving said at least one switch.

Claim 24

The method as recited in claim 17, further comprising a step of providing a waveform generator to generate said reference waveform.

Claim 25

The method as recited in claim 17 further comprising the step of generating a triangular waveform as said reference waveform.