Patent ID: 7098633

Claim:
A switching voltage converter, comprising: an input node for receiving an input voltage V in ; an output node at which said converter provides an output voltage V out ; a switching circuit which comprises: an inductor coupled between V in and a switching node, a switch connected to control the voltage applied across said inductor, said switching circuit arranged to cycle said switch and thereby produce a switching voltage V sw at said switching node, and a diode connected between said switching node and an intermediate node; an n-type transistor having its current circuit connected in series between said intermediate node and said output node such that said transistor conducts current from said intermediate node to said output node when on; a charge pump driven by said switching voltage V sw to provide a voltage V on at said n-type transistor's control input sufficient to turn said transistor on; and a series switch controller arranged to, in response to a control signal, hold said n-type transistor off such that output voltage V out is approximately zero regardless of the status of input voltage V in , or allow said n-type transistor to be turned on by V on .