Engim, Incorporated

Alexander Bugeja

The present invention dramatically reduces dynamic mismatches between the different current segments of a segmented current-mode DAC. By providing substantially the same local architecture for each of the individual current segments, parasitic effects of any physical realization can be controlled. In one embodiment, the most-significant-bit (MSB) current segments and the least-significant-bit (LSB) current segments each have the same number of multiple internal current branches. In the MSB segments, the multiple internal current branches are combined at a source node; whereas, in the LSB segment, a portion of the segment current is dumped, or wasted, through at least some of the internal current branches.

High dynamic linearity current-mode digital-to-analog converter architecture

An array of transistor circuits is fabricated so that each transistor circuit in an array of transistor circuits has a switching threshold determined by intrinsic switching thresholds of at least one sensing transistor in a corresponding transistor circuit. The sensing transistors in a set of transistor circuits of the array can be fabricated to have common physical dimensions even though corresponding intrinsic switching thresholds of the transistor circuits can vary. Switching thresholds of the transistor circuits can vary based on an applied well bias voltage. Alternatively, the switching threshold of each transistor circuit can be set to a common value and a tapped delay line can be coupled to the transistor circuits. Consequently, an A/D converter device can be fabricated by coupling an encoder, and a calibration circuit if necessary, to the output of the array of transistor circuits.

Circuit architectures and methods for A/D conversion

A method and circuit structure scale the power consumption of a current mode digital/analog converter (DAC) in proportion to performance parameters, such as sampling speed (i.e., clock samples per second) and resolution (number of bits) under programmable control. In one embodiment, a current mode segmented DAC provided approaches the performance of custom implementations designed for specific combinations of these parameters, across a wide range of such parameters by varying current relative to the sampling rate and the resolution and by selectively enabling current sources in the DAC.

Method and architecture for varying power consumption of a current mode digital/analog converter in proportion to performance parameters

A method for implementing segmented digital-analog converters (DACs) operating in the current mode matches the time constants in the most-significant-bit (MSB) segments to the time constants in the (LSB) least-significant-bit segments, and any intermediate-significant-bit (ISB) segments. The method can be implemented using the simple addition of capacitances or the resizing of transistors in the circuit at appropriate points. The resulting DAC exhibits high dynamic linearity and spurious free dynamic range (SFDR).

Method for implementing a segmented current-mode digital/analog converter with matched segment time constants

A sample and hold circuit including a capacitor is charged to a sample voltage from an open loop circuit such as a transistor circuit controlled by an input voltage. The sample voltage on the capacitor is converted to a digital signal via an ADC (Analog to Digital Converter). A digital correction circuit compensates for differences in voltage between the sample voltage on the capacitor and the input voltage based on properties of the open loop circuit and successive sample voltages on the capacitor. Consequently, nonlinearities can be compensated so that use of an open loop circuit or transistor circuit is less likely to negatively impact an overall accuracy of the ADC device.

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Acton, MA, United States of America

Alexander Bugeja