Very-low-voltage enhancement-mode MOSFETs can play a significant role in low-voltage designs

Voltage clamps for protecting low-voltage dc circuits require a new approach to circuit design. Many commonly used voltage clamps were built for systems of 5 V or higher, but lower-voltage systems require distinctive clamping abilities. The use of very-low-voltage precision enhancement-mode MOSFETs play a pivotal role in designing voltage clamps in low-voltage applications. Today’s electronic systems often include many different protection technologies in order to ward off ESD, EMI, voltage transients, and supply faults or fluctuations that can randomly occur on power supplies, analog signal lines, communication lines, and data buses. Laptop computers, for instance, include peripherals, open ports, buses, connecting signal cables, and power cables that are all vulnerable. Electromechanical disk drives can generate sudden load changes, and inductive switching often generates high levels of transient energy that is radiated around the system. Transient voltages often result from the sudden release of stored energy. In many systems, circuits share the same supply bus and power and data lines are often bundled together. Parasitic cable capacitances and inductances can create a path for transient voltages produced on the power lines and transferred to data lines. Connecting a USB cable into a socket, or hot-swapping a card or cable, can invisibly generate dangerous transients. Additionally, portable systems use dc/dc switching regulaVoltage clamp circuits for ultra-low-voltage apps