Delta-sigma modulator with oscillation detect and reset circuit
US5012244A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1989 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Oct 27, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/452
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An oscillation detect and reset circuit is provided for an analog modulator that includes a first stage of integration having a single ended differential amplifier (32) which is connected to the input of three stages of subsequent integration (40), (42) and (44), in a cascaded configuration. The output of the last stage of integration (44) is connected to the input of a one-bit quantizer (48). The output of the one-bit quantizer (48) is connected to the input of a current (50) feedback, which is connected between a summing node (36) and a negative voltage supply. The summing node (36) sums the current feedback with an input voltage for input to the amplifier (32). Switches (52), (54) and (56) are provided across the inputs and outputs of the integration stages (40), (42) and (44), respectively. The sensing of an unstable condition on the output of second stage of integration (40) is detected by oscillation detect comparators (60) and (62) to initiate a count cycle in a five-bit counter (66). The output of counter (66) generates a oscillation detect signal upon detection of an oscillation, which signal is output to the control inputs of the switches (52), (54) and (56), for thirty-t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.