Patent ID: 9660628
Date: 2017-05-23
CPC Classifications: H03K

Claim:
1. A circuit comprising: a resistor a first variable current source coupled to provide a selectable range of current levels to the resistor to produce a resistor voltage level; a voltage level detection circuit coupled to identify a resistor voltage level; a selection circuit configured to select a current level based at least in part upon the identified resistor voltage level; a second reference voltage; a capacitor; a comparator circuit configured to transition between providing a signal having a first value and providing a signal having a second value based at least in part upon comparisons of a capacitor voltage level with the identified resistor voltage level and with the second reference voltage; and a capacitor excitation circuit configured to reverse excitation of the capacitor in response to the comparator circuit transitioning between providing the signal having the first value and providing the signal having the second value.