Process-voltage sensor with smaller chip area
The present invention provides a PV sensor including a control circuit, a RC calibration circuit, and a voltage sensor. The control circuit is configured to generate at least one control signal. The RC calibration circuit is configured to receive the at least one control signal to generate a voltage indicates information of (1/R*C). The voltage sensor comprises a comparator, wherein the voltage sensor senses a voltage level of a received signal by using comparator to generate a sensing result, and the comparator is further configured to compare the calibration result within a reference voltage to generate a comparison result to the control circuit.
1 . A process-voltage (PV) sensor, comprising:
a control circuit, configured to generate at least one control signal;
a resistor-capacitor (RC) calibration circuit, configured to receive the at least one control signal to generate a first voltage that represents (1/(R*C)), where ‘R’ and ‘C’ are a resistor and a capacitor within the RC calibration circuit;
a multiplexer, configured to output one of the first voltage generated by the RC calibration circuit and a received signal; and
a voltage sensor comprising a comparator, wherein the voltage sensor senses a voltage level of the received signal by using the comparator to generate a sensing result when the multiplexer outputs the received signal, and the comparator is further configured to compare the first voltage with a reference voltage to generate a comparison result to the control circuit when the multiplexer outputs the first voltage.
2 . The PV sensor of claim 1 , wherein the at least one control signal comprises a RC-calibration enable signal; and when the RC-calibration enable signal has an enablement indication, the comparator of the voltage sensor is configured to compare the first voltage with the reference voltage to generate the comparison result to the control circuit; and when the RC-calibration enable signal does not have the enablement indication, the comparator is configured to generate another comparison result for generating the sensing result according to the received signal.
3 . The PV sensor of claim 2 ,
wherein the multiplexer is configured to output the one of the first voltage generated by the RC calibration circuit and the received signal to the voltage sensor according to the RC-calibration enable signal.
4 . The PV sensor of claim 1 , wherein the voltage sensor comprises an analog-to-digital converter comprising the comparator.
5 . The PV sensor of claim 4 , wherein the voltage sensor comprises a single-slope analog-to-digital converter (SSADC) comprising the comparator.
6 . The PV sensor of claim 5 , wherein the voltage sensor comprises:
a ramp signal generator, configured to generate a ramp signal;
the comparator, configured to compare the received signal with the ramp signal to generate another comparison result; and
a counter, coupled to the comparator, configured to increase/update a counter value according to the another comparison result, wherein the counter value is used to generate the sensing result of the voltage sensor.
7 . The PV sensor of claim 6 , wherein the at least one control signal comprises a RC-calibration enable signal; and when the RC-calibration enable signal has an enablement indication, the comparator of the voltage sensor is configured to compare the first voltage with the reference voltage to generate the comparison result to the control circuit; and when the RC-calibration enable signal does not have the enablement indication, the comparator is configured to compare the received signal with the ramp signal to generate the another comparison result.
8 . The PV sensor of claim 7 ,
wherein the multiplexer is configured to output one of the first voltage generated by the RC calibration circuit and the received signal to the voltage sensor according to the RC-calibration enable signal.