Detection circuit for detecting the amplitude of a clock signal and detection method thereof
AssigneeNuvoton Technology Corporation
InventorCheng-Chih Wang
Life of this patent
Estimating the term…
Abstract
A detection circuit for detecting a clock signal includes a multiplexer, a digital-to-analog converter, a comparator, and a counter. The multiplexer outputs either a first signal or a second signal as a selection signal. The digital-to-analog converter outputs a reference voltage according to the selection signal. The comparator compares the clock signal to the reference voltage to generate a comparison signal. The counter counts a reference clock signal to generate an overflow signal, and resets the overflow signal according to the comparison signal. The overflow signal indicates the amplitude of the clock signal.
Claims20
A detection circuit for detecting a clock signal, comprising:
- a multiplexer, outputting either a first signal or a second signal as a selection signal according to a comparison signal;
- a digital-to-analog converter, outputting a reference voltage according to the selection signal;
- a comparator, comparing the clock signal to the reference voltage to generate the comparison signal;
- and
- a counter, counting a number of pulses of a reference clock signal to generate an overflow signal and resetting the overflow signal according to the comparison signal, wherein the overflow signal indicates amplitude of the clock signal.
An electronic circuit, comprising:
- a detection circuit, comprising:
- a multiplexer, outputting the first signal or the second signal as a selection signal according to a comparison signal;
- a digital-to-analog converter, outputting a reference voltage according to the selection signal;
- a comparator, comparing the clock signal to the reference voltage to generate the comparison signal;
- and
- a counter, counting a number of pulses of a reference clock signal to generate an overflow signal and resetting the overflow signal according to the comparison signal, wherein the overflow signal indicates amplitude of the clock signal;
- an oscillation circuit, generating the clock signal and comprising:
- an amplifier, amplifying a signal of a first node with a gain to generate the clock signal at a second node and generating the gain according to a gain signal;
- and
- a quartz crystal, electrically connected between the first node and the second node;
- and
- a controller, generating the gain signal according to the overflow signal.
A detection method for detecting a clock signal generated by an oscillation circuit, wherein the oscillation circuit comprises an amplifier having a gain, wherein the detection method comprises:
- comparing the clock signal to a first reference voltage and a second reference voltage to generate a comparison signal;
- by using a counter, counting a number of pulses of a reference clock signal to generate an overflow signal;
- when the clock signal oscillates outside the range of the first reference voltage and the second reference voltage, resetting the overflow signal to be a second voltage level via the comparison signal;
- and
- adjusting the gain according to the overflow signal.
Dependencies are inferred from the claim text.