RF switch with bypass topology
An RF signal switch circuit that allows connection of any of N radio frequency (RF) input terminals to a switch output port, either in a low loss mode, in a bypass mode, or, optionally, in a signal function mode. Embodiments of the invention allow for both a single switch in the series input path to a target circuit while still having the ability to isolate the bypass path from the target circuit. In the low loss and bypass mode, the circuit simultaneously exhibits low input insertion loss (and thus a low noise factor) and high bypass mode isolation.
1. A radio frequency (RF) signal switch circuit, including:
(a) at least one first type RF signal port, each first type RF signal port having:
(1) a first shunt switch coupled to the first type RF signal port and configured to selectively couple the first type RF signal port to circuit ground,
(2) a first series switch coupled between the first type RF signal port and at least one corresponding second type RF signal port, and
(3) at least one set of second series switches coupled to the first type RF signal port;
(b) at least one first circuit path each coupled to a corresponding second shunt switch and coupled to a corresponding one set of second series switches, each first circuit path being configured to be coupled to at least one target circuit;
(c) at least one second circuit path configured to be coupled to at least one target circuit, and being coupled to a corresponding third shunt switch; and
(d) at least one third series switch coupled to a corresponding one second circuit path and to at least one corresponding second type RF signal port.
2. A radio frequency (RF) signal switch, including a plurality of RF input ports each coupled to a corresponding selectable ground shunt path, a corresponding selectable bypass path couplable to a switch output port, and at least one corresponding selectable signal path configured to be coupled to an input of a corresponding target circuit, and a switch path selectively couplable coupled to the switch output port and configured to be coupled to an output of the corresponding target circuit.
3. The invention of claim 2 , wherein the RF signal switch in an in-circuit mode may be configured such that a signal applied to a selected RF input port passes to the input of a selected coupled target circuit through the selectable signal path corresponding to the selected RF input port, and to no other coupled target circuit.
4. The invention of claim 2 , wherein the RF signal switch in a bypass mode may be configured such that a signal applied to a selected RF input port passes to the switch output port through the selectable bypass path corresponding to the selected RF input port, and to no coupled target circuit.
5. The invention of claim 2 , wherein the selectable ground shunt path, the selectable bypass path, and the at least one selectable signal path each include at least one respective field effect transistor switch operable to select or de-select the respective path.
6. The invention of claim 2 , wherein the selectable bypass path includes a “T” type series/shunt/series bypass switch circuit.
7. A radio frequency (RF) signal switch, including:
(a) at least one RF input port coupled to a corresponding switch group having an independently selectable ground shunt path configured to selectively couple the corresponding at least one RF input port to ground, an independently selectable bypass path couplable to a switch output port, and at least one independently selectable signal path;
(b) at least one shuntable in-circuit path coupled to at least one corresponding selectable signal path, each shuntable in-circuit path configured to be coupled to an input of a corresponding target circuit; and
(c) at least one series/shunt switch each configured to be coupled to an output of one target circuit corresponding to one of the at least one shuntable in-circuit path and couplable to the switch output port.
8. The invention of claim 7 , wherein the RF signal switch in an in-circuit mode may be configured such that a signal applied to a selected RF input port passes to the input of a selected coupled target circuit through the selectable signal path of the switch group corresponding to the selected RF input port, and to no other coupled target circuit.
9. The invention of claim 7 , wherein the RF signal switch in a bypass mode may be configured such that a signal applied to a selected RF input port passes to the switch output port through the selectable bypass path of the switch group corresponding to the selected RF input port, and to no coupled target circuit.
10. The invention of claim 9 , wherein in the bypass mode, each shuntable in-circuit path coupled to the input of each corresponding target circuit is set to a shunted state, thereby isolating the input of each corresponding target circuit from the switch output port.
11. The invention of claim 7 , wherein the selectable ground shunt path, the selectable bypass path, and the at least one selectable signal path each include at least one respective field effect transistor switch operable to select or de-select the respective path.
12. The invention of claim 7 , wherein the selectable bypass path includes a “T” type series/shunt/series bypass switch circuit.
13. A radio frequency (RF) signal switch, including:
(a) at least one RF input port coupled to a corresponding switch group having an independently selectable ground shunt path configured to selectively couple the corresponding at least one RF input port to ground, an independently selectable bypass path couplable to a switch output port, and at least one independently selectable signal path configured to be coupled to an input of at least one corresponding target circuit; and
(b) at least one series/shunt switch each configured to be coupled to an output of a corresponding one of the at least one corresponding target circuit and couplable to the switch output port.
14. The invention of claim 13 , wherein the RF signal switch in an in-circuit mode may be configured such that a signal applied to a selected RF input port passes to the input of a selected coupled target circuit through the selectable signal path of the switch group corresponding to the selected RF input port, and to no other coupled target circuit.
15. The invention of claim 13 , wherein the RF signal switch in a bypass mode may be configured such that a signal applied to a selected RF input port passes to the switch output port through the selectable bypass path of the switch group corresponding to the selected RF input port, and to no coupled target circuit.
16. The invention of claim 13 , wherein the selectable ground shunt path, the selectable bypass path, and the at least one selectable signal path each include at least one respective field effect transistor switch operable to select or de-select the respective path.
17. The invention of claim 13 , wherein the selectable bypass path includes a “T” type series/shunt/series bypass switch circuit.
18. The invention of claim 13 , wherein at least one selectable signal path can be independently isolated.
19. The invention of claim 13 , further including a signal function circuit coupled to the selectable bypass paths of the switch groups, and a corresponding series/shunt switch coupled to the signal function circuit and configured to be coupled to an input of at least one corresponding target circuit, wherein when the RF signal switch is configured in a signal function mode for a selected RF input port and a selected coupled target circuit, a signal applied to the selected RF input port passes to the input of the selected coupled target circuit through the selectable bypass path of the switch group corresponding to the selected RF input port, and through the signal function circuit and the corresponding series/shunt switch, and to no other coupled target circuit.
20. The invention of claim 19 , wherein the signal function circuit has a selectable bypass mode.
21. The invention of claim 19 , further including a “T” type series/shunt/series bypass switch circuit coupled between the switch output port and the signal function circuit.