| 摘要 |
A reference ladder is configured to have improved feedback stability. The reference ladder includes a resistor ladder having a plurality of taps that produce a plurality of reference voltages. The resistor ladder is driven by a first current source at a first tap of the plurality of taps and by a second current source at a second tap of the plurality of taps. A first feedback network senses a voltage at the first tap and controls the first current source based on the first sensed voltage. A second feedback network senses a voltage at the second tap and controls the second current source based on the second sensed voltage. The first and second taps each operate as both a force tap and a sense tap of the resistor ladder. Differential input stages that are connected to the plurality of taps are at least partially isolated from the feedback networks by converging the force and sense taps, thereby improving the stability of the feedback networks. An alternate embodiment includes first and second resistor ladders that are configured to generate substantially identical voltages across their respective taps. First and second feedback networks sense voltages on the first resistor ladder and control current sources that drive both the first resistor ladder and the second resistor ladder. Differential input stages that are connected to the taps of the second resistor ladder and are at least partially isolated from the feedback networks that are connected to the first resistor ladder, thereby improving stability of the feedback networks. <IMAGE> |
