SUB-MICRON CMOS VCO THAT USES DELAY-BASED CALIBRATION AND METHOD OF OPERATION
A system for calibrating a circuit comprising a delay to voltage converter for receiving an input signal and generating an output signal that represents a delay metric. A counter for receiving the output signal and generating a binary output as a function of the delay metric.
1 . A system for calibrating a circuit comprising:
a delay to voltage converter for receiving an input signal and generating an output signal that represents a delay metric; and
a counter for receiving the output signal and generating a binary output as a function of the delay metric.
2 . The system of claim 1 further comprising a delay for generating the input signal, wherein the input signal comprises a pulse having a width proportional to the delay metric.
3 . The system of claim 1 wherein the delay metric is a function of PVT variations.
4 . The system of claim 1 further comprising:
a voltage reference; and
a comparator for receiving the voltage reference and the output signal from the delay to voltage converter, wherein the comparator is for generating the output signal for the counter when a magnitude of the output signal from the delay to voltage converter exceeds a magnitude of the reference voltage.
5 . The system of claim 1 further comprising a plurality of switches, and each of the switches is coupled to a capacitor.
6 . The system of claim 1 further comprising a plurality of switches, and each of the switches is coupled to a capacitor, wherein each digit of the binary output controls a state of one of the switches.
7 . The system of claim 1 , further comprising a plurality of capacitor banks, wherein each capacitor bank comprises a plurality of switches, and each of the switches is coupled to a capacitor.
8 . The system of claim 7 , further comprising a plurality of inverters, and each of the inverters is coupled to one or more of the capacitor banks.
9 . The system of claim 1 , further comprising a voltage source controller coupled to the counter and receiving the binary output, wherein the binary output controls a voltage level applied to a plurality of inverters by the voltage source controller.
10 . A method for calibrating a circuit comprising:
applying a reference signal to a delay;
providing an output from the delay to a delay to voltage converter, wherein the output of the delay varies as a function of a circuit parameter of the delay; and
generating a binary output as a function of an output of the delay to voltage converter.
11 . The method of claim 10 wherein generating the binary output as the function of the output of the delay to voltage converter comprises:
comparing the output of the delay to voltage converter to a reference voltage; and
terminating a counter when the output of the delay to voltage converter exceeds the reference voltage.
12 . The method of claim 11 wherein the counter generates the binary output.
13 . The method of claim 10 further comprising controlling a plurality of switches with the binary output.
14 . The method of claim 10 further comprising controlling a state of each of a plurality of switches with the binary output, wherein each digit of the binary output controls the state of one of the switches.
15 . The method of claim 10 further comprising controlling a plurality of switches with the binary output, wherein each of the switches is coupled to a capacitor.
16 . The method of claim 10 further comprising controlling a plurality of capacitor banks with the binary output, wherein each of the capacitor banks is coupled to one or more inverter.
17 . The method of claim 10 further comprising controlling a plurality of capacitor banks with the binary output, wherein each digit of the binary output controls the state of one of a plurality of switches in each of the capacitor banks.
18 . The method of claim 17 further comprising controlling a voltage level controller with the binary output, wherein the voltage level controller controls two or more voltage levels applied to a plurality of inverters as a function of the binary output.
19 . A system for calibrating a circuit comprising:
means for receiving an input signal and generating an output signal that represents a delay metric; and
means for receiving the output signal and generating a binary output as a function of the delay metric.