A detection circuit includes a tunable delay circuit that generates a delayed signal and that receives a supply voltage. The detection circuit includes a control circuit that adjusts a delay provided by the tunable delay circuit to the delayed signal. The detection circuit includes a time-to-digital converter circuit that converts the delay provided by the tunable delay circuit to the delayed signal to a digital code and adjusts the digital code based on changes in the supply voltage. The control circuit causes the tunable delay circuit to maintain the delay provided to the delayed signal constant in response to the digital code reaching an alignment value. The detection circuit may continuously monitor timing margin of a data signal relative to a clock signal and update the digital code in every clock cycle. The detection circuit may be a security sensor that detects changes in the supply voltage.