Patent ID: 8416010

Claim:
An adaptive charge pump, comprising: first and second nodes which are toggled to opposite states between first and second supply voltages; a first capacitor coupled between said first node and a third node, a second capacitor coupled between said second node and a fourth node, and a third capacitor coupled between an output node and said second supply voltage; a first transistor of a first conductivity type having a first current terminal coupled to a control node, having a second current terminal coupled to said third node and having a control terminal coupled to said fourth node; a second transistor of said first conductivity type having a first current terminal coupled to said control node, having a second current terminal coupled to said fourth node and having a control terminal coupled to said third node; a third transistor of a second conductivity type having a first current terminal coupled to said third node, having a second current terminal coupled to said output node and having a control terminal coupled to said fourth node; a fourth transistor of said second conductivity type having a first current terminal coupled to said fourth node, having a second current terminal coupled to said output node and having a control terminal coupled to said third node; and a controller which controls said control node to be about the same voltage level as said first supply voltage while a voltage difference between said output node and said second supply voltage does not exceed a limit voltage, and which otherwise controls voltage of said control node to prevent said voltage difference from exceeding said limit voltage.