Self oscillating power amplifier
AssigneeAlcatel
InventorsTim Piessens, Michiel Steyaert
Life of this patent
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Abstract
A power amplifier includes a comparator (COMP) to which an input signal is applied , a digital buffer (BUF) coupled via a feedback low-pass filter (LPFB) to a second input terminal (Cin2) of said comparator (COMP). An unstable loop is thereby created with an oscillation frequency related to the bandwidth of the feedback low-pass filter. In the presence of an input signal this self-oscillation frequency linearizes the system resulting in a power amplifier with excellent power efficiency. In a differential version two of these self-oscillating loops are provided . The coupling of the two loops thereby withhelds the high-frequency self-oscillation from the load.
Claims8
Power Amplifier arrangement (AS) including an input terminal (IN) for coupling to an input signal (vin) source, said amplifier arrangement further including a comparator (COMP), a first input terminal (Cin) of which is coupled to said input terminal (IN) of said amplifier arrangement, an output terminal (Cout) of which is coupled to an input terminal (Bin) of a digital buffer (BUF) of said amplifier arrangement, a buffer output terminal (Bout) of said digital buffer being coupled to an output terminal (OUT) of said amplifier arrangement (AS) and to a second input terminal (Cin2) of said comparator (COMP) characterized in that
- said buffer output terminal (BOUT) is coupled via a feedback low-pass filter (LPFB) of said amplifier arrangement (AS), to said second input terminal (Cin2) of said comparator (COMP).
Differential power amplifier arrangement (AD) including a pair of differential input terminals (IN1,IN2) to which a differential input voltage (vdiff) can be applied, and a pair of differential output terminal (OUT1,OUT2) for coupling to a load (Rload)
- said differential power amplifier arrangement including a first self-oscillating loop with an input terminal coupled to a first one (IN1) of said pair of differential input terminals, said first self-oscillating loop including a first comparator (COMP1) coupled to a first digital buffer (BUF1) , an output terminal of which is coupled to a second input terminal of said first comparator via a first low-pass filter (LPFB1),
- said differential power amplifier arrangement incuding a second self- oscillating loop with an input terminal coupled to a second one (IN2) of said pair of differential input terminals, said second self-oscillating loop including a second comparator (COMP2) coupled to a second digital buffer (BUF2), an output terminal of which is coupled to a second input terminal of said second comparator via a second low-pass filter (LPFB2).
Dependencies are inferred from the claim text.