The present IP is a VCC Detector (VDT) circuit. It detects the voltage level of its power supply, AV28. The normal operating voltage range of AV28 is (3.0~3.6)v. When the detected voltage on AV28 rises beyond the detection level VR28, the corresponding output OUTP15 is generated as a high level logic. When the detected voltage on AV28 falls below the detection level VF28, the corresponding output OUTP15 is generated as a low level logic. This system consists of one comparator sub-circuit and needs an external bandgap. The output may be in the wrong voltage level during the power-up phase before the bandgap becomes stable.