Utility ground detection

In an embodiment, a missing utility ground detection circuit includes a pair of balanced resistors each connected to receive utility voltage from a different one of a pair of utility power lines, the balanced resistors being connected together at a summing node to be capable of summing the voltages from the pair of utility power lines. It includes an unbalance resistor connected to shunt voltage from one of the utility power lines. It has a summing amplifier with an input coupled to the summing node and to a reference voltage, and an input coupled to a second reference voltage. It has an averaging circuit connected at the output of the summing amplifier. A comparator is provided having an input connected to the averaging circuit an input connected to a threshold voltage. 在实施例中，缺少公用设施接地侦测电路(missing utility ground detection circuit)包括对平衡电阻器，连接每平衡电阻器以接收公用设施电压，所述公用设施电压是来自对公用设施电源线的不同电源线，将所述平衡电阻器在加总节点处连接在起以能够将来自所述对公用设施电源线的电压进行合计。所述缺少公用设施接地侦测电路包括不平衡电阻器，连接所述不平衡电阻器以便对来自所述公用设施电源线的电源线的电压进行分路。所述缺少公用设施接地侦测电路具有加法放大器，所述加法放大