Projeto de amplificador operacional para análise de emissões conduzidas e pré-conformidade em dispositivos eletrônicos

Abstract

Technological innovation has enabled the current power grid to connected to different electronic devices. Current electronic devices generate conducted emissions due, in large part, because of the switched sources at the input of these devices. Because of this, every electronic device is subjected to an electromagnetic compliance test to verify that such emissions are at acceptable levels so as not to influence adjacent devices and also to verify the ability of a device to resist such emissions. This procedure is performed in controlled environments and for this reason has a high price. Based on this, in the first phase of this project a low-cost alternative platform for measuring emissions conducted with operational amplifiers is developed. In order to optimize the signals measured in the alternative platform, an operational transconductance (OTA) amplifier with low dissipated power, a high slew rate and a low output resistance is designed in the second phase and in its design is adopted the technology 0.35μm of AustriaMicroSystem . The analysis of the alternative platform indicates that this device is capable of increasing sensitivity compared to similar devices on the market. In this way, 2 operational amplifiers were designed to be applied in the alternative platform, one with 5V of symmetrical power supply and the other with 3.3V of symmetrical power, in these amplifiers it is found that the output resistance is less than 1000 Ω and the dissipated power is lower than 3 mW. To improve the output resistance a 2-stage operational amplifier circuit with output buffer is designed that results in an output resistance less than 100Ω.