| 摘要 |
<p>A tree of field effect transistor switches (16, 18...30, 32...50, 52...) comprises pairs of complementary switches arranged in a succession of levels with the switches at each level controlled by a digital signal on a corresponding input line (12, 14, 15). Each pair of highest level switches is connected to a corresponding capacitor (82, 86...). All of the capacitors are connected to a charging current source (114) and a periodically operated discharging switch (132). The switches connect down through the tree levels to a main output line (51), a complementary output line (53) and an interpolation line (55). When the capacitors are discharged by closing the switch (132) the numner of capacitors which discharge to the output line (51) represents the digital value on the input lines (12, 14, 15). One capacitor always discharges to the interpolation line (55) to provide a scaled down charging current for a lower significance converter. The remaining capacitors discharge to the complementary output line (53).</p> |
