Relaxation oscillator
AssigneeMediatek Inc.
InventorKeng-Jan Hsiao
Life of this patent
Estimating the term…
Abstract
A relaxation oscillator is provided. A first current source provides a first current. A second current source provides a second current. A resistive element is coupled between the first current source and a ground. A capacitive element is coupled between the second current source and the ground. A comparator has a non-inverting input terminal, an inverting input terminal and an output terminal for outputting a compare result. A clock generator provides a clock signal according to the compare result. A switching unit alternately couples the non-inverting input terminal and the inverting input terminal of the comparator to the resistive element and the capacitive element according to the clock signal.
Claims14
A relaxation oscillator, comprising:
- a current mirror coupled to a power supply, having a first output terminal for providing a first current and a second output terminal for providing a second current;
- a first transistor, having a first terminal, a second terminal and a first gate, wherein the first terminal and the first gate are coupled to the first output terminal of the current mirror;
- a second transistor, having a third terminal, a fourth terminal and a second gate, wherein the third terminal is coupled to the second output terminal of the current mirror, and the second gate is coupled to the first gate of the first transistor;
- a first resistor coupled to a ground;
- a capacitor coupled to the ground;
- a first switching unit coupled to the first and second transistors, the first resistor and the capacitor, alternately coupling the first resistor and the capacitor to the second terminal of the first transistor and the fourth terminal of the second transistor according to a clock signal;
- a comparator, comparing the voltages of the first and second output terminals of the current mirror or comparing the voltages of the first resistor and the capacitor to obtain a compare result;
- and
- a clock generator, providing the clock signal according to the compare result.
Dependencies are inferred from the claim text.