Digital-to-analog converter apparatus having a reconfigurable resistor-capacitor circuit

摘要

A digital-to-analog converter apparatus includes a digital-to-analog converter, a resistor-capacitor circuit, a quantizer and a controller. The resistor-capacitor circuit includes an operational amplifier, a first capacitor, a second capacitor, a first resistor, a second resistor, a first switch and a second switch. The digital-to-analog converter may generate a plurality of currents. The quantizer may generate a plurality of offset values. The controller may control coupling of the plurality of currents to the operational amplifier.

主权项

1. A digital-to-analog converter apparatus comprising:
a digital-to-analog converter having an input bus terminal, a first output terminal, a second output terminal, and a plurality of control terminals, and configured to generate a plurality of currents; a resistor-capacitor circuit configured to form an integrator to form a sigma-delta analog-to-digital converter during calibration and configured to form a low-pass filter during a digital-to-analog conversion, the resistor-capacitor circuit comprising:
an operational amplifier having a first input terminal coupled to the first output terminal of the digital-to-analog converter, a second input terminal coupled to the second output terminal of the digital-to-analog converter, a first output terminal, and a second output terminal;a first capacitor having a first terminal coupled to the first input terminal of the operational amplifier and a second terminal coupled to the first output terminal of the operational amplifier;a second capacitor having a first terminal coupled to the second input terminal of the operational amplifier and a second terminal coupled to the second output terminal of the operational amplifier;a first resistor having a first terminal coupled to the first input terminal of the operational amplifier and a second terminal;a second resistor having a first terminal coupled to the second input terminal of the operational amplifier and a second terminal;a first switch having a first terminal coupled to the second terminal of the first resistor, a second terminal selectively coupled to a common mode voltage or to the first output terminal of the operational amplifier; anda second switch having a first terminal coupled to the second terminal of the second resistor, a second terminal selectively coupled to the common mode voltage or to the second output terminal of the operational amplifier; a quantizer having a first input terminal coupled to the first output terminal of the operational amplifier, a second input terminal coupled to the second output terminal of the operational amplifier, and an output terminal, and configured to generate a plurality of offset values according to outputs of the operational amplifier; and a controller having an input terminal coupled to the output terminal of the quantizer, and an output bus terminal coupled to the plurality of control terminals of the digital-to-analog converter, and configured to control coupling of the plurality of currents to the operational amplifier according to the plurality of offset values.