An enabling circuit includes a comparison circuit configured to compare a feedback
signal representative of a charge of an energy storage element of a regulating
circuit with a reference charge and provide an output in response to the comparison
to enable the regulating circuit to switch from a first state to a second state
if the charge of the energy storage element is less than the reference charge.
The enabling circuit may also be used to enable a synchronous rectifier converter
to provide a charging current to a battery in a battery charging system of an electronic
device thereby avoiding negative voltage transients that may otherwise occur at
the output of the synchronous rectifier converter. Various methods are also provided.
