CONTROLLING OPERATION OF A SECONDARY POWER SUPPLY OF AN ELECTRICITY METER DURING AC POWER LOSS

An AC line voltage detection circuit includes an AC sense circuit, a power supply control circuit, and a power supply hold-up circuit. The AC sense circuit is configured to generate a signal to a processor and to the power supply control circuit in response to sensing an absence of AC line voltage. The power supply control circuit is configured to generate a control signal to a power supply that provides power to the processor to shut down the power supply. The processor is configured generate a signal to the power supply hold-up circuit configured to generate a signal to the power supply control circuit to prevent shut down of the power supply. The power supply hold-up circuit signal overrides the AC sense circuit signal. The processor is further configured to generate a subsequent signal to the power supply hold-up circuit to permit shut down of the power supply.