Patent ID: 7655990

Claim:
A semiconductor device, comprising: a substrate of a first conductive type; a quasi-linked well of a second conductive type having the a first depletion boundary disposed in the substrate, wherein the quasi-linked well is formed by two adjacent wells having a gap with a width therebetween; a first well of the first conductive type having the a second depletion boundary disposed in the quasi-linked well; a first heavily doped region of the first conductive type disposed in the first well; a second heavily doped region of the second conductive type disposed in the quasi-linked well outside a first side of the first well; a third heavily doped region of the second conductive type disposed in the quasi-linked well outside a second side of the first well; and an isolation layer disposed over the quasi-linked well and the first well, and between the first heavily doped region and the second heavily doped region and between the first heavily doped region and the third heavily doped region; wherein the first depletion boundary of the quasi-linked well and the depletion boundary of the first well is modulated according to voltage variations, and a maximum output-voltage potential at an output terminal of said semiconductor device is controlled by a control-voltage potential.