| 摘要 |
<p>A digital to analogue converter comprising at least two resistor ladders (A, B) and at least two banks of switches (SwA, SwB etc.), means for controlling said switches in accordance with at least the MSBs of a digital input signal, connecting means (Rx) for connecting the two resistor ladders at their ends to form a ring topology, said connecting means comprising means for deriving two analogue output signals to form a differential analogue output signal. The output means may include further resistance ladders and switch banks (C, D) to provide higher resolution in segmented fashion. The first and second banks of switches are on the supply side of the ladders, to avoid loading effects. Optionally each switch forms one of a matched pair of switches controlled to be closed and opened as a pair, the second switch in operation providing feedback to an amplifier (AMPA, AMPB) such that a reference voltage can be imposed on the ladder independently of the resistance of the switches.</p> |
