Passive filter selectivity with precise resolution for integrated circuit radios

An integrated circuit radio transceiver, comprising:

• a baseband processor for generating outgoing digital signals and for receiving and processing ingoing digital signals;
• front-end circuitry for producing outgoing RF based upon the outgoing digital signals and for producing the ingoing digital signals based upon received ingoing RF;
• and
• a current source operably disposed to provide a current signal within the front-end circuitry, the current source including:
• a first transistor that includes an input and an output for a current path;
• and
• a high resolution resistive circuit operably disposed to conduct current of the current path, wherein an amount of current conducted is based upon a resistive value of the high resolution resistive circuit, and further wherein the resistive circuit is operable to selectively provide very high resolution changes to output current levels of the current source wherein the resistive circuit comprises a plurality of selectable parallel paths each having a plurality of series coupled resistive elements.

An integrated circuit radio transceiver, comprising:

• a baseband processor for generating outgoing digital signals and for receiving and processing ingoing digital signals;
• front-end circuitry for producing outgoing RF based upon the outgoing digital signals and for producing the ingoing digital signals based upon received ingoing RF;
• and
• a voltage source operably disposed to provide a current signal within the front-end circuitry, the voltage source including:
• a constant current source;
• a high resolution resistive circuit operably disposed to conduct constant current produced by the constant current source;
• and
• an output node coupled electrically between the constant current source and the high resolution resistive circuit, the output node for producing an output voltage level wherein the output voltage level is based upon the an amount of constant current conducted through the high resolution resistive circuit, and further wherein the resistive circuit is operable to selectively provide very high resolution changes to output voltage levels wherein the resistive circuit comprises a plurality of selectable parallel paths each having a plurality of series coupled resistive elements.

A method for setting a signal level based upon a resistive setting, comprising:

• selecting and coupling at least one resistive path of a plurality of selectable very high resolution resistive paths of a very high resolution resistive block to be operably disposed in parallel to a base resistive path;
• comparing a corresponding signal level to a desired signal level;
• and
• selectively coupling at least one very high resolution resistive path or de-coupling at least one very high resolution resistive path of the plurality of selectable very high resolution resistive paths of the very high resolution resistive block if the corresponding signal level is not within a specified tolerance of the desired signal level.