Current switching circuitry

Digital-to-analog conversion circuitry comprising:

• a plurality of circuitry segments, each having first and second connection nodes through which first and second controllable currents pass respectively when the circuitry is in use, and switch circuitry for changing the respective magnitudes of the first and second controllable currents in dependence upon a switching signal applied to the segment;
• a first combiner, connected with the respective first connection nodes of the segments and also connected operatively with a first combined signal terminal, for combining the respective first controllable currents of the segments to produce a first combined signal at said first combined signal terminal;
• a second combiner, connected with the respective second connection nodes of the segments and also connected operatively with a second combined signal terminal, for combining the respective second controllable currents of the segments to produce a second combined signal at said second combined signal terminal;
• a first shielding circuit, connected between said first combined signal terminal and said switch circuitry in one or more of said segments, for shielding the switch circuitry in the segment(s) concerned from variations in potential arising from variations in potential of that terminal;
• a second shielding circuit, connected between said second combined signal terminal and said switch circuitry in said one or more segments, for shielding the switch circuitry in the segment(s) concerned from variations in potential arising from variations in potential of that terminal;
• and
• decoder circuitry connected for receiving a digital input signal to be converted into a corresponding analog output signal, and operable to derive from the received digital input signal a set of said switching signals for application respectively to said segments.

Current switching circuitry comprising:

• a plurality of circuitry segments, each having first and second connection nodes through which first and second controllable currents pass respectively when the circuitry is in use, and switching means for changing the respective magnitudes of the first and second controllable currents in dependence upon a switching signal applied to the segment;
• first combining means, connected with the respective first connection nodes of the segments and also connected operatively with a first combined signal terminal, for combining the respective first controllable currents of the segments to produce a first combined signal at said first combined signal terminal;
• second combining means, connected with the respective second connection nodes of the segments and also connected operatively with a second combined signal terminal, for combining the respective second controllable currents of the segments to produce a second combined signal at said second combined signal terminal;
• first shielding means, connected between said first combined signal terminal and said switching means in one or more of said segments, for shielding the switching means in the segment(s) concerned from variations in potential arising from variations in potential of that terminal;
• and
• second shielding means, connected between said second combined signal terminal and said switching means in said one or more segments, for shielding the switching means in the segment(s) concerned from variations in potential arising from variations in potential of that terminal.

Digital-to-analog conversion circuitry comprising:

• a plurality of circuitry segments, each having first and second connection nodes through which first and second controllable currents pass respectively when the circuitry is in use, and switching means for changing the respective magnitudes of the first and second controllable currents in dependence upon a switching signal applied to the segment;
• first combining means, connected with the respective first connection nodes of the segments and also connected operatively with a first combined signal terminal, for combining the respective first controllable currents of the segments to produce a first combined signal at said first combined signal terminal;
• second combining means, connected with the respective second connection nodes of the segments and also connected operatively with a second combined signal terminal, for combining the respective second controllable currents of the segments to produce a second combined signal at said second combined signal terminal;
• first shielding means, connected between said first combined signal terminal and said switching means in one or more of said segments, for shielding the switching means in the segment(s) concerned from variations in potential arising from variations in potential of that terminal;
• second shielding means, connected between said second combined signal terminal and said switching means in said one or more segments, for shielding the switching means in the segment(s) concerned from variations in potential arising from variations in potential of that terminal;
• and
• decoder circuitry connected for receiving a digital input signal to be converted into a corresponding analog output signal, and operable to derive from the received digital input signal a set of said switching signals for application respectively to said segments.