Circuitry for providing digitally stable ground

An apparatus arranged for attachment to a luminaire having one or more light emitting elements and a receptacle, the apparatus comprising:

• a housing;
• a connector accessible from an exterior of the housing, the connector including a set of connector elements that interface with corresponding receptacle elements of the receptacle of the luminaire;
• one or more processor-based devices housed at least in part within the housing, the one or more processor-based devices being operable by receiving direct current (DC) power relative to a digitally stable ground;
• first circuitry for detecting a stray voltage between the housing and a neutral power line signal passed through the connector;
• and
• second circuitry for converting alternating current (AC) power received at the connector into the DC power and for providing the digitally stable ground, the second circuitry including:
• a pair of circuitry inputs, a first input of the pair of inputs being connected to a first connector element of the set of connector elements, and a second input of the pair of inputs being connected to a second connector element of the set of connector elements;
• a first ground node and a second ground node galvanically isolated from the first ground node;
• a transformer that galvanically isolates the first ground node from the second ground node, the transformer including a primary winding, a secondary winding coupled to the second ground node, and an auxiliary winding coupled to the first ground node;
• a first set of electrical components for providing filtered and rectified power to the primary winding;
• a solid-state switching device connected between the primary winding and the first ground node;
• a pulse width modulation (PWM) controller that controls switching of the solid-state switching device, the PWM controller powered by power received from the auxiliary winding and coupled to the first ground node;
• an output capacitor and a diode coupled to the secondary winding and providing a DC voltage output relative to the second ground node;
• an error compensation subcircuit that provides an error signal based at least in part on the DC voltage output, the error compensation subcircuit coupled to the second ground node;
• an optical isolator that provides a feedback signal to the PWM controller based at least in part on the error signal;
• a DC output node;
• and
• a digitally stable ground galvanically isolated from a mains power ground node.