OSCILLATOR CIRCUIT AND SEMICONDUCTOR DEVICE INCLUDING THE SAME

摘要

Controllability of an oscillator circuit is improved. The oscillator circuit has inverters in odd-numbered stages. A circuit is electrically connected to a power supply node of the inverters to which a high power supply potential is input. The circuit includes a first transistor, a second transistor, and a capacitor. The first transistor includes an oxide semiconductor in its channel. A holding circuit including the first transistor and the capacitor has a function of holding an analog potential that is input from the outside. The potential held by the holding circuit is input to a gate of the second transistor. A power supply potential is supplied to the inverters through the second transistor, so that the delay time of the inverter can be controlled by the potential of the gate of the second transistor.

主权项

1. An oscillator circuit comprising:
first- to n-th-stage first circuits (n is an odd number); and a second circuit, wherein each of the first to n-th-stage first circuits includes a first input node, a first output node, an inverter, and a third circuit, wherein the first output node of the first circuit in an i-th stage (i is an integer greater than or equal to 1 and less than or equal to (n−1)) is electrically connected to the first input node of the first circuit in a next stage, wherein the output node of the first circuit in the n-th stage is electrically connected to the input node of the first circuit in the first stage, wherein an input node of the inverter is electrically connected to the first input node, wherein an output node of the inverter is electrically connected to the first output node, wherein the inverter includes a first power supply node and a second power supply node, wherein the third circuit includes a second input node, a second output node, a third node, a first transistor, a second transistor, and a first capacitor, wherein the second output node is electrically connected to the first power supply node, wherein a first potential is input to the second input node, wherein a first terminal of the first transistor is electrically connected to the second input node, wherein a second terminal of the first transistor is electrically connected to the third node, wherein the first transistor includes an oxide semiconductor in its channel, wherein the first capacitor has a function of holding a potential of the third node, wherein a gate of the second transistor is electrically connected to the third node, wherein a second potential is input to a first terminal of the second transistor, wherein a second terminal of the second transistor is electrically connected to the second output node, and wherein the second circuit has a function of changing an amplitude of an output signal of the first output node of the first circuit in the n-th stage.