Oversampling A-D converter using single amplifier loop filter

As a loop filter of an oversampling A-D converter using a 1-bit quantizer, a switched capacitor integrator suitable to implement on a monolithic IC is generally used. However, there are several problems from the points of vie w of reduction of power consumption and increase of operating frequency, du e to the need for several integrators and to the feedthrough of the clock. In this paper, a configuration of an oversampling A-D converter using a 1-b it quantizer suitable for low-power, high-frequency operation, in which a s ingle operational amplifier with RC elements in the loop filter is used, is discussed. A method of configuration of the loop filter and an example of third-order design are presented. By means of computer simulation and a mea surement experiment with a trial circuit realized with discrete components, the operation of the proposed A-D converter is confirmed. (C) 1999 Scripta Technica, Electron Comm Jpn Pt 2, 83(1): 24-32, 2000.