Patent ID: 6724336
Filing Date: 2004-04-20
Classification: H03M

Abstract:
A digital-to-analog converter, comprising:a first and second resistor string, each said resistor string characterized by a plurality of resistors for providing plural analog voltage levels; a differential amplifier having one input coupled to a precision voltage, and another input coupled by a feedback circuit of said amplifier to the first resistor string for driving said first resistor string with a voltage reference; a current mirror circuit for carrying current to said first resistor string, said current mirror circuit driven by said amplifier; a current source for driving said second resistor string with a current, said current source including a current mirror driven by said amplifier, whereby changes in a current driven in said first resistor string are reflected in said second resistor string; switching circuitry for selectively connecting one of said plurality of resistors in said first resistor string across said second resistor string; and an output amplifier for receiving an analog voltage level resulting from said second resistor string.