Amplifiers
AssigneeCirrus Logic International Semiconductor Ltd.
InventorJohn P. LESSO
Life of this patent
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Abstract
This application relates to an amplifier selectively operable in first or second modes. The first mode is a BTL mode with first and second output drivers (103p, 103n) both active to generate respective driving signals that vary with an input signal. The second mode is an SE mode, where the first output driver (103p) is active to generate a driving signal at and the output of the second driver (103n) is held constant. A controller (201) selectively controls the mode based on an indication of output signal amplitude. In the first mode, a ratio of magnitude of the two driving signals varies with the indication of output signal amplitude, i.e. the magnitudes of the two driving signals may vary so as to be not equal.
Claims19
-20. (canceled)
A switching driver comprising:
- a first switching driver stage for selectively connecting a first output node to any of at least two different switching voltages;
- and
- a modulator configured to control the first switching driver stage so as to modulate the first output node between selected ones of said at least two different switching voltages with a controlled duty-cycle to output a first output signal at the first output node;
- wherein the switching driver is operable in at least first and second modes of operation, wherein:
- in the first mode of operation the modulator is configured to receive a first feedback signal of the first output signal tapped from a first feedback point and control the first switching driver stage based on the first feedback signal;
- and
- in the second mode of operation the modulator is configured to receive a second feedback signal of the first output signal tapped from a second feedback point, different to the first feedback point, and control the first switching driver stage based on the second feedback signal.
A switching driver comprising:
- a switching driver stage for selectively connecting an output node to any of at least two different switching voltages;
- and
- a modulator configured to control the switching driver stage so as to modulate the output node between selected ones of said at least two different switching voltages with a controlled duty-cycle to output an output signal at the first output node;
- wherein the modulator is configured to be operable to receive a first feedback signal of the output signal in a first mode of operation and to receive a second, different, feedback signal of the output signal in a second mode of operation.
A switching driver apparatus comprising:
- a first switching driver stage for selectively connecting a first output node to any of at least two different switching voltages;
- and
- a modulator configured to control the first switching driver stage so as to modulate the first output node between selected ones of said at least two different switching voltages with a controlled duty-cycle to output a first output signal at the first output node;
- an output path extending from the first output node to a load, the first output path comprising a first filter;
- wherein the switching driver is operable in at least first and second modes of operation, wherein:
- in the first mode of operation the modulator is configured to receive a first feedback signal from the output path upstream of the first filter;
- and
- in the second mode of operation the modulator is configured to receive a second feedback signal from the output path downstream of the first filter.
Dependencies are inferred from the claim text.