NxM crosspoint switch with band translation
View Patent ↗An N×M crosspoint switch allows a signal from any one of the N inputs to be routed to one or more of the M crosspoint switch outputs. The switches within the crosspoint switch can be configured as voltage mode or current mode switches. In voltage mode switching an input to the crosspoint switch is provided to an input device, such as an amplifier, having a low output impedance. The output of the low impedance device is provided to a switch that connects the output of the low impedance device to a high input impedance device, such as a band translation device. In current mode switching, the low impedance output of the input device is connected to selectively activated high isolation transconductance devices having high input impedances. The outputs of the transconductance devices are connected to low impedance devices that operate as summing nodes.
1. An N-input by M-output crosspoint switch with frequency translation integrated circuit for use in distributing signals supplied from N input sources coupled to the N-input by M-output crosspoint switch, the integrated circuit comprising:
an N-input by M-output crosspoint switch configured to route a signal supplied to any one of the N inputs to any one or more of the M outputs, the N-input by M-output crosspoint switch comprising N groups of M switches, each group of M switches having one switch input and M switch outputs, each of the N switch inputs configured to couple to a separate one of the N signal sources, wherein each of the N switch inputs has a high input impedance relative to the output impedance of the input source supplying said signal thereto; and
a plurality of M frequency translation devices, each M frequency translation device coupled to one of the M switch outputs,
wherein (i) each of the frequency translation devices has a high input impedance relative to the output impedance of each of the N input sources, wherein each switch in the N groups of M switches comprises a voltage mode switch, and wherein the voltage mode switch is operable to present the high input impedance of one or more of the M frequency translation devices to one or more of the N switch inputs , or (ii) each switch in the N groups of M switches comprises a current mode switch having a high input impedance relative to the output impedance of each of the N input sources.
2. The integrated circuit of claim 1 , wherein each current mode switch comprises a transconductance device.
3. The integrated circuit of claim 2 , wherein each current mode switch is selectively enabled or disabled based on a control signal.
4. The integrated circuit of claim 1 , wherein each voltage mode switch comprises a switch.
5. The integrated circuit of claim 1 , wherein each voltage mode switch or current mode switch in the N groups of M switches is operable to provide greater than 30 dB of signal isolation.
6. The integrated circuit of claim 1 , further comprising N low noise amplifiers (LNAs) with each LNA having an output coupled to a separate input on the N input switch.
7. The integrated circuit of claim 1 , wherein the N-input by M-output crosspoint switch and the M frequency translation devices include differential signal inputs and differential signal outputs.
8. The integrated circuit of claim 1 , further comprising a first low noise amplifier (LNA) having a differential input and a low impedance differential output,
wherein the N-input by M-output crosspoint switch comprises:
a first transconductance device having a differential output and a high impedance differential input connected to the low impedance differential output of the first LNA; and
a second transconductance device having a differential output and a high impedance differential input connected to the low impedance differential output of the first LNA; and
wherein the M frequency translation devices comprise:
a first frequency translation device having a differential output and a low impedance differential input connected to the differential output of the first transconductance device; and
a second frequency translation device having a differential output and a low impedance differential input connected to the differential output of the second transconductance device.
9. The integrated circuit of claim 8 , wherein the first transconductance device comprises a controllable current source configured to selectively enable and disable the first transconductance device.
10. A method of routing signals in a reconfigurable signal distribution system, the method comprising:
receiving a signal at a matched impedance input of an amplifier having a low output impedance;
selectively routing an output voltage of the amplifier, using a first transconductance device having a high impedance input, as a current at an output of the first transconductance device;
selectively routing an output voltage of the amplifier, using a second transconductance device having a high impedance input, as a current at an output of the second transconductance device; and
frequency translating a signal at the output of the first transconductance device from a first RF frequency to a second RF frequency using a first frequency translation device.
11. A method of routing signals in a reconfigurable signal distribution system, the method comprising:
receiving an input signal at a matched impedance input of an input device;
generating an intermediate signal, based in part on the input signal, at a low impedance output of the input device;
providing the intermediate signal to a high impedance input of a transconductance device;
selectively enabling the transconductance device to provide an output current signal based in part on the intermediate signal;
receiving the output current signal at a low impedance input of a frequency translation device; and
frequency translating the output current signal from a first frequency to a second frequency.