High efficiency switched gain power amplifier

A power amplifier circuit arrangement, comprising:

• a driver amplifier for transmitting an analog signal;
• a first switch for selectively switching the analog signal between a bypass path and an amplifier path, said amplifier path comprising:
• a band-pass filter for filtering the analog signal and for producing a filtered signal;
• a power amplifier for receiving the filtered signal and for producing an amplified signal;
• a first hybrid circuit for splitting the amplified signal into an in-phase signal and a quadrature signal;
• and
• a second hybrid circuit for inverting the quadrature signal to produce an inverted signal and for summing the inverted signal and the in-phase signal to produce a summed signal,
• said bypass path connecting an output of said driver amplifier with an isolated port of said second hybrid circuit when said first switch switches the analog signal to said bypass path, whereby the analog signal transmitted from said driver amplifier will reflect off of said power amplifier and be routed to an output port.

A method for amplifying a signal in a circuit having a driver amplifier, an amplifier path comprising a first switch, a band-pass filter, a power amplifier, a first hybrid circuit and a second hybrid circuit, and a bypass path connecting an isolated port of the second hybrid circuit to the first switch, said method comprising:

• (A) producing a driver signal from the driver amplifier;
• (B) selectively switching the driver signal between the amplifier path and the bypass path using the first switch,
• wherein when the driver signal is switched in said switching step to the amplifier path, said method further comprises the steps of:
• (a) band-pass filtering the driver signal by the band-pass filter to produce a filtered signal;
• (b) amplifying the filtered signal by the power amplifier to produce an amplified signal;
• (c) splitting the amplified signal into an in-phase signal and a quadrature signal in the first hybrid circuit;
• (d) inverting the in-phase signal to produce an inverted signal in the second hybrid circuit;
• and
• (e) summing the inverted signal and the quadrature signal to produce a summed signal in the second hybrid circuit,
• and wherein when the driver signal is switched in said switching step to the bypass path, said method further comprises the steps of:
• (a) turning off the power amplifier;
• (b) transmitting the driver signal to the isolated port of the second hybrid circuit;
• (c) reflecting the driver signal off an output of the power amplifier to an output port.

A power amplifier circuit arrangement, comprising:

• a driver amplifier for transmitting an analog signal;
• a first switch for switching the analog signal between a bypass path and an amplifier path, said amplifier path comprising:
• a band pass filter which filters the analog signal to produce a filtered signal;
• a first hybrid circuit for splitting the filtered signal into an in-phase signal and a quadrature signal;
• a first power amplifier for amplifying the in-phase signal to produce a first amplified signal;
• a second power amplifier for amplifying the quadrature signal to produce a second amplified signal;
• and
• a second hybrid circuit for inverting the first amplified signal to produce an inverted signal and for summing the inverted signal and the second amplified signal,
• said bypass path connecting an output of said driver amplifier and an isolated port of said second hybrid circuit when said first switch switches the analog signal to said bypass path.

A power amplifier circuit arrangement, comprising:

• a driver amplifier for transmitting an analog signal;
• a first switch for switching the analog signal between a bypass path and an amplifier path, said amplifier path comprising:
• a band pass filter which filters the analog signal to produce a filtered signal;
• a first hybrid circuit for splitting the filtered signal into an in-phase signal and a quadrature signal;
• a first power amplifier for amplifying the in-phase signal to produce a first amplified signal;
• a second power amplifier for amplifying the quadrature signal to produce a second amplified signal;
• and
• a second hybrid circuit for inverting the second amplified signal to produce an inverted signal and for summing the inverted signal and the first amplified signal,
• said bypass path connecting an output of said driver amplifier and an isolated port of said second hybrid circuit when said first switch switches the analog signal to said bypass path.

A method for amplifying a signal in a circuit having a driver amplifier, an amplifier path comprising a first switch, a band-pass filter, a first power amplifier, a second power amplifier, a first hybrid circuit and a second hybrid circuit, and a bypass path connecting an isolated port of the second hybrid circuit with the first switch, said method comprising:

• (A) producing a driver signal from the driver amplifier;
• (B) selectively switching the driver signal between the amplifier path and the bypass path using the first switch,
• wherein when the driver signal is switched in said switching step to the amplifier path, said method further comprises:
• (a) band-pass filtering the driver signal by the band-pass filter to produce a filtered signal;
• (b) splitting the filtered signal in the first hybrid circuit into an in-phase signal and a quadrature signal;
• (c) amplifying the in-phase signal by the first power amplifier to produce an amplified in-phase signal;
• (d) amplifying the quadrature signal by the second power amplifier to produce an amplified quadrature signal;
• (e) inverting the amplified in-phase signal in the second hybrid circuit to produce an inverted signal;
• and
• (f) summing the inverted signal and the amplified quadrature signal in the second hybrid circuit to produce a summed signal,
• and wherein when the driver signal is switched in said switching step to the bypass path, said method further comprises:
• (a) turning off the first power amplifier and the second power amplifier;
• (b) transmitting the driver signal to the isolated port of the second hybrid circuit;
• (c) splitting the driver signal into an in-phase signal and a quadrature signal in the second hybrid circuit;
• (d) reflecting the in-phase signal off of the first amplifier signal;
• (e) reflecting the quadrature signal off of the second power amplifier;
• (f) inverting the reflected in-phase signal in the second hybrid circuit to produce an inverted signal;
• (g) summing the inverted signal and the quadrature signal in the second hybrid circuit to produce a summed signal;
• and
• (h) outputting the summed signal to an output port.

A method for amplifying a signal in a circuit having a driver amplifier, an amplifier path comprising a first switch, a band-pass filter, a first power amplifier, a second power amplifier, a first hybrid circuit and a second hybrid circuit, and a bypass path connecting an isolated port of the second hybrid circuit with the first switch, said method comprising:

• (A) producing a driver signal from the driver amplifier;
• (B) selectively switching the driver signal between the amplifier path and the bypass path using the first switch,
• wherein when the driver signal is switched in said switching step to the amplifier path, said method further comprises:
• (a) band-pass filtering the driver signal by the band-pass filter to produce a filtered signal;
• (b) splitting the filtered signal in the first hybrid circuit into an in-phase signal and a quadrature signal;
• (c) amplifying the in-phase signal by the first power amplifier to produce an amplified in-phase signal;
• (d) amplifying the quadrature signal by the second power amplifier to produce an amplified quadrature signal;
• (e) inverting the amplified quadrature signal in the second hybrid circuit to produce an inverted signal;
• and
• (f) summing the inverted signal and the amplified in-phase signal in the second hybrid circuit to produce a summed signal,
• and wherein when the driver signal is switched in said switching step to the bypass path, said method further comprises:
• (a) turning off the first power amplifier and the second power amplifier;
• (b) transmitting the driver signal to the isolated port of the second hybrid circuit;
• (c) splitting the driver signal into an in-phase signal and a quadrature signal in the second hybrid circuit;
• (d) reflecting the in-phase signal off of the first amplifier signal;
• (e) reflecting the quadrature signal off of the second power amplifier;
• (f) inverting the reflected quadrature signal in the second hybrid circuit to produce an inverted signal;
• (g) summing the inverted signal and the in-phase in the second hybrid circuit to produce a summed signal;
• and
• (h) outputting the summed signal to an output port.

A mobile communication unit having a power supply, a digital processor, a receiving chain, a transmitting chain, a duplexer, an antenna, and user interfacing means, said mobile communication unit comprising:

• a power amplifier circuit arrangement in said transmitting chain, said power amplifier circuit comprising:
• a driver amplifier for transmitting an analog signal;
• a first switch for selectively switching the analog signal between a bypass path and an amplifier path, said amplifier path comprising:
• a band-pass filter for filtering the analog signal and for producing a filtered signal;
• a power amplifier for receiving the filtered signal and for producing an amplified signal;
• a first hybrid circuit for splitting the amplified signal into an in-phase signal and a quadrature signal;
• and
• a second hybrid circuit for inverting the in-phase signal to produce an inverted signal and for summing the inverted signal and the quadrature signal to produce a summed signal,
• said bypass path connecting an output of said driver amplifier with an isolated port of said second hybrid circuit when said first switch switches the analog signal to said bypass path, whereby the analog signal transmitted from said driver amplifier will reflect off of said power amplifier and be routed to an output port.

A mobile communication unit having a power supply, a digital processor, a receiving chain, a transmitting chain, a duplexer, an antenna, and user interfacing means, said mobile communication unit comprising:

• a power amplifier circuit arrangement in said transmitting chain, said power amplifier circuit arrangement comprising:
• a driver amplifier for transmitting an analog signal;
• a first switch for switching the analog signal between a bypass path and an amplifier path, said amplifier path comprising:
• a band pass filter which filters the analog signal to produce a filtered signal;
• a first hybrid circuit for splitting the filtered signal into an in-phase signal and a quadrature signal;
• a first power amplifier for amplifying the in-phase signal to produce a first amplified signal;
• a second power amplifier for amplifying the quadrature signal to produce a second amplified signal;
• and
• a second hybrid circuit for inverting the first amplified signal to produce an inverted signal and for summing the inverted signal and the second amplified signal,
• said bypass path connecting an output of said driver amplifier and an isolated port of said second hybrid circuit when said first switch switches the analog signal to said bypass path.