This work presents a novel circuit for detecting transient faults in combinational and sequential logic. The detection mechanism features a built-in current sensor connected to the bulks of the monitored logic. The proposed circuit was optimized in terms of power consumption and enhanced with low-power sleep-mode. In addition, a calibration method for bulk built-in current sensors is presented. Overhead results indicate an increase of only 15% in power consumption which represents an improvement of almost factor 6 compared to similar existing sensor.