Multi-mode power amplifier signal switching
A switching circuit comprises a first transistor, a transformer including a first inductor and a second inductor that is co-centric with the first inductor, a first switch, a second switch, a second transistor, a first output, a second output, and coupling circuitry configured to couple the first inductor to the first transistor, a first end of the second inductor, the first switch, and the first output together at a first node, a second end of the second inductor, the second switch, and the second transistor together at a second node, and the second output to the second transistor.
1 . A switching circuit comprising:
a first transistor;
a transformer including a first inductor and a second inductor that is co-centric with the first inductor;
a first switch;
a second switch;
a second transistor;
a first output;
a second output; and
a matching network coupled between the second output and the second transistor;
the first inductor coupled to the first transistor, a first end of the second inductor, the first switch, and the first output together at a first node, a second end of the second inductor coupled to the second switch and the second transistor together at a second node, and the second output coupled to the second transistor.
2 . The switching circuit of claim 1 wherein the first inductor is coupled to a collector of the first transistor.
3 . The switching circuit of claim 1 wherein the first switch is a shunt switch.
4 . The switching circuit of claim 1 wherein the second switch is a shunt switch.
5 . The switching circuit of claim 1 further comprising a matching network, wherein the matching network is coupled between the first output and the first node.
6 . The switching circuit of claim 1 wherein the matching network is coupled to a collector of the second transistor.
7 . The switching circuit of claim 1 wherein the first transistor is a second-stage amplifier.
8 . The switching circuit of claim 7 wherein the second transistor is a third-stage amplifier.
9 . The switching circuit of claim 1 further comprising an inter-stage network, wherein the inter-stage network is coupled between the second transistor and the second node.
10 . The switching circuit of claim 1 wherein the first switch is configured to be biased to an OFF state to direct a signal to the second output.
11 . The switching circuit of claim 1 wherein the second switch is configured to be biased to an OFF state to direct a signal to the first output.
12 . The switching circuit of claim 1 wherein the first output is a low-gain output.
13 . The switching circuit of claim 1 wherein the second output is a high-gain output.
14 . A semiconductor die comprising:
a first transistor;
a transformer comprising a first inductor and a second inductor that is co-centric with the first inductor;
a first switch;
a second switch;
a second transistor;
a first output;
a second output; and
a matching network coupled between the second output and the second transistor;
the first inductor coupled to the first transistor, a first end of the second inductor, the first switch, and the first output together at a first node, a second end of the second inductor coupled to the second switch and the second transistor together at a second node, and the second output coupled to the second transistor.
15 . The semiconductor die of claim 14 wherein the first inductor is coupled to a collector of the first transistor.
16 . The semiconductor die of claim 14 further comprising a matching network, wherein the matching network is coupled between the first output and the first node.
17 . A packaged module comprising:
a first transistor;
a transformer comprising a first inductor and a second inductor that is co-centric with the first inductor;
a first switch;
a second switch;
a second transistor;
a first output;
a second output; and
a matching network coupled between the second output and the second transistor;
the first inductor coupled to the first transistor, a first end of the second inductor, the first switch, and the first output together at a first node, a second end of the second inductor coupled to the second switch and the second transistor together at a second node, and the second output coupled to the second transistor.
18 . The packaged module of claim 17 further comprising a matching network, wherein the matching network is coupled between the first output and the first node.