Programmable peak detector for use with zero-overhead Class G line drivers
AssigneeTexas Instruments Incorporated
InventorPeter J. Melsa
Life of this patent
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Abstract
A digital input signal is analyzed by a peak detector (210) configurable to trigger a first logic signal (260) if the peak detector detects the digital input signal level crossing a certain threshold. The threshold value can be modified by an overhead. The amplifier (250) employs a plurality of supply rails of differing voltages (253, 255) as a function of the logic signals. A digital signal delay element (220) may delay the signal to allow sufficient time for the amplifier to switch between supply sources. A logic delay element (280) may delay transmittal of the first logic signal by the peak detector to compensate for signal delay caused by a filter. A hold element (270) ensures that the first logic signal is applied to the output amplifier for a given amount of time.
Claims24
A line driver, comprising:
- a signal input;
- a peak detector receiving a digital data signal from the signal input and outputting a logic signal having a first logic value when the digital data signal exceeds a threshold value and a second logic value when the digital data signal is below the threshold value, said threshold value modifiable by an overhead value;
- a data signal delay coupled to the digital data signal input and outputting a time-delayed digital data signal;
- a DAC coupled to the signal input and receiving as input the time-delayed digital data signal and outputting an analog data signal;
- a filter receiving as input the analog data signal and outputting a filtered analog data signal;
- and
- an amplifier receiving as input the filtered analog data signal from the filter and the logic signal, the amplifier operating at a first operating voltage level when the logic signal is at the first logic value and operating at a second operating voltage level when the logic signal is at the second logic value, wherein the threshold value is associated with a proportionality between a peak value associated with the first operating voltage level and a rms value associated with the first operating voltage level.
A method of operation of a line driver, comprising the steps of:
- receiving a digital data signal from a signal input and outputting a first logic value when the digital data signal exceeds a threshold value and a second logic value when the digital data signal is below the threshold value, said threshold value modifiable by an overhead value;
- delaying digital data signal by a programmable digital data signal delay value;
- converting the digital data signal to an analog data signal;
- filtering the analog data signal;
- passing the filtered analog data signal to an amplifier operable at a first operating voltage level and a second operating voltage level;
- and
- selecting between the first operating voltage level and the second operating voltage level in response to the first or second logic value, wherein the threshold value is associated with a proportionality between a peak value associated with the first operating voltage level and a rms value associated with the first operating voltage level.
A line driver system, comprising:
- a signal input;
- a peak detector receiving a digital data signal from the signal input and outputting a logic signal having a first logic value when the digital data signal exceeds a threshold value and a second logic value when the digital data signal is below the threshold value, said threshold value modifiable by an overhead value;
- a data signal delay coupled to the digital data signal input employed to output a time delayed digital data signal;
- a DAC coupled to the signal input and receiving as input the digital data signal and outputting an analog data signal;
- a filter receiving as input the analog data signal and outputting a filtered analog data signal;
- an amplifier receiving as input the filtered analog data signal from the filter and the time delayed logic signal, the amplifier operating at a first operating voltage level when the time delayed logic signal is at the first logic value and operating at a second operating voltage level when the logic signal is at the second logic value;
- a transmission line coupled to an output of the amplifier;
- and
- a receiver coupled to an output of the transmission line, wherein the threshold value is associated with a proportionality between a between a peak value associated with the first operating voltage level and an rms value associated with the first operating voltage level.
Dependencies are inferred from the claim text.