PERFORMANCE OPTIMIZATION OF POWER SCALED DELTA SIGMA MODULATORS USING A RECONFIGURABLE GM-ARRAY
First Claim
1. A transceiver front-end circuit for a cellular radio, said transceiver circuit comprising:
- an antenna operable to receive signals;
a multiplexer coupled to the antenna and including a plurality of signal paths, each signal path including a bandpass filter that passes a different frequency band than the other bandpass filters and a circulator that provides signal isolation between the transmit signals and the receive signals; and
a receiver module including a separate signal channel for each of the signal paths in the multiplexer, each signal channel in the receiver module including a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal, each delta-sigma modulator including a reconfigurable field programmable analog array (FPAA) having a plurality of gm cells operating as transconductance amplifiers, said FPAA operating as an N-order filter and including a plurality of resonator stages where each stage includes at least two gm cells, a summation junction responsive to output signals from the at least two gm cells and an inductance-capacitance (LC) filter circuit, each delta-sigma modulator further including a coefficient controller operable to activate or deactivate selective ones of the gm cells so as to control a dynamic range of the delta-sigma modulator and/or decrease or increase an order of the delta-sigma modulator.
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Accused Products
Abstract
A cellular radio architecture that includes a receiver module having a delta-sigma modulator that includes a plurality of gm cells configured in stages, where each stage includes at least two gm cells and an LC filter circuit. The gm cells in each stage can be controlled to be active or inactive to convert, for example, the modulator from a fourth order modulator to a second order modulator to reduce power dissipation. Further, the gm cells can be controlled to optimize a dynamic range of the modulator and to redirect current from inactive cells to active cells in order to optimize power consumption.
29 Citations
20 Claims
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1. A transceiver front-end circuit for a cellular radio, said transceiver circuit comprising:
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an antenna operable to receive signals; a multiplexer coupled to the antenna and including a plurality of signal paths, each signal path including a bandpass filter that passes a different frequency band than the other bandpass filters and a circulator that provides signal isolation between the transmit signals and the receive signals; and a receiver module including a separate signal channel for each of the signal paths in the multiplexer, each signal channel in the receiver module including a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal, each delta-sigma modulator including a reconfigurable field programmable analog array (FPAA) having a plurality of gm cells operating as transconductance amplifiers, said FPAA operating as an N-order filter and including a plurality of resonator stages where each stage includes at least two gm cells, a summation junction responsive to output signals from the at least two gm cells and an inductance-capacitance (LC) filter circuit, each delta-sigma modulator further including a coefficient controller operable to activate or deactivate selective ones of the gm cells so as to control a dynamic range of the delta-sigma modulator and/or decrease or increase an order of the delta-sigma modulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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- 14. A receiver module for a front-end circuit of a radio, said receiver module comprising a delta-sigma modulator including an array of gm cells operating as transconductance amplifiers, said delta-sigma modulator including a plurality of resonator stages where each stage includes at least two gm cells, a summation junction responsive to output signals from the at least two gm cells and an inductance-capacitance (LC) filter circuit, said delta-sigma modulator further including a coefficient controller operable to activate or deactivate selective ones of the gm cells by adding or removing transconductance for the gm cells to control a dynamic range of the delta-sigma modulator and/or decrease or increase the order of the modulator.
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20. A receiver module for a front-end circuit of a radio, said receiver module comprising a fourth order delta-sigma modulator including an array of gm cells operating as transconductance amplifiers, said delta-sigma modulator including a plurality of resonator stages where each stage includes at least two gm cells, a summation junction responsive to output signals from the at least two gm cells and an inductance-capacitance (LC) filter circuit, said delta-sigma modulator further including a coefficient controller operable to activate or deactivate selective ones of the gm cells by adding or removing transconductance for the gm cells to control a dynamic range of the delta-sigma modulator and/or decrease or increase the order of the delta-sigma modulator, wherein the coefficient controller deactivates the gm cells in at least one of the resonator stages so as to convert the fourth order modulator to a second order modulator, said delta-sigma modulator further including a current source routing network and a plurality of current sources, said current source routing network selectively providing current to the gm cells from the current sources, wherein the current source routing network selectively removes current from certain ones of the gm cells and directs current to other gm cells having a high transconductance.
Specification