Controller for ground fault circuit interrupter applications adds self test and lockout
The NCS37010 is a signal processor from onsemi which offers self test and lockout for ground fault circuit interrupter (GFCI) applications.
Fully compliant to UL943, the NCS37010 GFCI controller integrates a flexible power supply which integrates shunt and LDO regulators, in addition to providing differential fault, and grounded-neutral detection.
Performance is improved, and the number of external components is minimized, by proprietary impedance measurement and signal processing techniques. A specialized DSP controller offers best-in-class immunity to nuisance loads, without the need to add external analog filters.
A self test at 60ms is performed at power-up and the lockout is removed if the test is passed. The self test combines differential, ground-neutral and solenoid tests.
The self syncing of the internal oscillator adjusts to the AC mains frequency to guarantee full resolution for 50Hz and 60Hz distribution systems. There is also a randomized testing sequence for noise sensitivity and potential interactions on the AC mains. Differential and grounded-neutral faults are detected with the single current transformer.