Charge Pump Latch-Up Prevention via Equipotential Well Coupling

The patent applies equipotentiality by coupling the n-well and p-well regions to a common local potential (V LOW ), creating an equipotential environment that prevents voltage differences between these regions. This eliminates the forward biasing condition of parasitic pnp and npn structures, allowing the charge pump to operate at high voltages without latch-up. The common potential coupling ensures that both wells remain at the same electrical potential, preventing harmful current flow through parasitic paths.

The equipotentiality principle addresses temperature-related latch-up by maintaining common potential coupling between n-well and p-well regions. At elevated temperatures, parasitic structures become more active, but the equipotential connection ensures no voltage differential exists to drive latch-up currents. This approach allows extended temperature operation without compromising reliability.

The patent maintains minimal device complexity by implementing equipotentiality through simple potential coupling connections rather than complex active control circuits. The n-well and p-well regions are coupled to V LOW through straightforward electrical connections, avoiding the need for additional transistors, sensors, or control logic. This simple equipotential approach prevents latch-up and reduces power consumption without significantly increasing device complexity.

The patent resolves the manufacturing simplicity versus parasitic activation contradiction by implementing equipotentiality through potential coupling. Instead of leaving wells floating or using complex isolation structures, the invention couples n-well and p-well to a common potential (V LOW ), which is a simple manufacturing step. This equipotential connection prevents parasitic transistor activation while maintaining ease of manufacture, as it requires only standard doping and connection processes.