High linearly WiGig baseband amplifier with channel select filter
View Patent ↗A circuit comprises a Sallen-Key filter, which includes a source follower that implements a unity-gain amplifier; and a programmable-gain amplifier coupled to the Sallen-Key filter. The circuit enables programmable gain via adjustment to a current mirror copying ratio in the programmable-gain amplifier, which decouples the bandwidth of the circuit from its gain settings. The programmable-gain amplifier can comprise a differential voltage-to-current converter, a current mirror pair, and programmable output gain stages. The Sallen-Key filter and at least one branch in the programmable-gain amplifier can comprise transistors arranged in identical circuit configurations.
1. A WiGig baseband signal-processing circuit comprising:
a first stage filter including a source follower configuring a unity-gain amplifier; and
a programmable-gain amplifier coupled to the first stage filter, the baseband signal-processing circuit configured to at least provide a programmable gain by at least an adjustment to a current mirror copying ratio in the programmable-gain amplifier to decouple a bandwidth setting of the baseband signal-processing circuit from its gain setting.
2. The WiGig baseband signal-processing circuit of claim 1 , wherein the current mirror copying ratio is a ratio between a pair of transistors of a current mirror.
3. The WiGig baseband signal-processing circuit of claim 1 , wherein an input signal of the source follower is in phase with an output signal of the source follower.
4. The WiGig baseband signal-processing circuit of claim 1 , wherein the programmable-gain amplifier comprises:
a differential voltage-to-current converter, a current mirror pair, and programmable output gain stages.
5. The WiGig baseband signal-processing circuit of claim 4 , wherein the differential voltage-to-current converter and a first current mirror share a first transistor and the differential voltage-to-current converter and a second current mirror share a second transistor.
6. The WiGig baseband signal-processing circuit of claim 4 , further comprising:
a first gain stage of the programmable output and the first current mirror share a third transistor; and
a second gain stage of the programmable output and the second current mirror share a fourth transistor.
7. The WiGig baseband signal-processing circuit of claim 6 , wherein the first gain stage and the second gain stage convert input differential currents to output differential voltages.
8. The WiGig baseband signal-processing circuit of claim 1 , wherein the source follower comprises:
a first circuit including a first plurality of transistors; and
a second circuit, in a branch within the programmable-gain amplifier, including a second plurality of transistors, wherein the second circuit has an identical configuration as the first circuit.
9. The WiGig baseband signal-processing circuit of claim 1 , wherein a gain of the programmable-gain amplifier is based on the current mirror copying ratio and a ratio between a first resistor and a second resistor.
10. The WiGig baseband signal-processing circuit of claim 1 , wherein the first stage filter comprises a low-pass filter.
11. The WiGig baseband signal-processing circuit of claim 1 , wherein the first stage filter comprises a high-pass filter.
12. The WiGig baseband signal-processing circuit of claim 1 , wherein the first stage filter comprises a band-pass filter.
13. The WiGig baseband signal-processing circuit of claim 1 , wherein the first stage filter is configured as a Sallen-Key filter.
14. The WiGig baseband signal-processing circuit of claim 1 , further comprising:
an integrated circuit layout including a uniform array of unit devices.
15. The WiGig baseband signal-processing circuit of claim 8 , wherein the first plurality of transistors and the second plurality of transistors have the same unit device sizes and current densities.
16. The WiGig baseband signal-processing circuit of claim 8 , wherein the first circuit is configured as an active device and the second circuit is configured as a load device.
17. The WiGig baseband signal-processing circuit of claim 16 , wherein the load device provides a controlled current load to the active device.
18. The WiGig baseband signal-processing circuit of claim 16 , wherein the load device provides a direct current bias to operate the source follower.