Circuitry for providing digitally stable ground

An apparatus mountable to a streetlight fixture that includes a receptacle and a luminaire, the apparatus comprising:

• a housing;
• a communications module located within the housing and operable to provide access to a cellular-based network;
• a light sensor;
• a processor-based light control circuit operable to provide a light control signal for controlling operation of the luminaire based on an output of the light sensor;
• a connector accessible from an exterior of the housing, the connector including a set of connector elements that are interfaceable with corresponding receptacle elements of the receptacle of the streetlight fixture;
• first circuitry operable to detect a stray voltage between the housing and a neutral power line signal passed through the connector;
• and
• second circuitry operable to convert alternating current power received at the connector into direct current (DC) power and provide a digitally stable ground, the second circuitry including:
• a pair of 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;
• a second 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 that provide filtered and rectified power to the primary winding of the transformer;
• a switching device connected between the primary winding of the transformer and the first ground node;
• a switching controller that controls switching of the switching device, the switching controller being powered by power received from the auxiliary winding of the transformer and coupled to the first ground node;
• an output capacitor and a diode coupled to the secondary winding of the transformer 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 being coupled to the second ground node;
• and
• an optical isolator that provides a feedback signal to the switching controller based at least in part on the error signal.