TVS (Transient Voltage Suppressor) diodes, also known as transient suppressor diodes or transient voltage protection diodes, are specialized components designed to protect electronic circuits from voltage spikes and surges. These voltage spikes can result from various sources, such as lightning strikes, electrostatic discharge (ESD), inductive loads turning off, and other transient events. TVS diodes provide a low-resistance path for excess voltage to be redirected away from sensitive components, preventing damage and maintaining the integrity of the circuit. Here's how they work:
Zener Breakdown: TVS diodes are designed to exhibit a specific breakdown voltage, often slightly higher than the normal operating voltage of the protected circuit. Once the voltage across the diode exceeds its breakdown voltage, it enters a state called "avalanche breakdown" or "Zener breakdown." During this breakdown, the diode's resistance drops significantly, allowing a large current to flow through it.
Low Clamping Voltage: When a transient voltage spike occurs, the TVS diode quickly switches into its low-resistance state. This effectively limits the voltage across the protected circuit to a level near the breakdown voltage of the diode. This voltage is referred to as the "clamping voltage." The clamping voltage is much lower than what would otherwise be experienced by the circuit, offering robust protection to the components.
Fast Response Time: TVS diodes are designed to have a fast response time, often in the nanosecond range. This ensures that they begin conducting current and clamping the voltage almost immediately after a transient event occurs. This rapid response time prevents the transient voltage from reaching and damaging sensitive components.
Bipolar Protection: TVS diodes are bidirectional devices, meaning they can handle voltage spikes in both polarities (positive and negative). This makes them suitable for protecting circuits that may experience voltage fluctuations in either direction.
Absorption of Energy: During a transient event, the TVS diode absorbs the energy of the spike by conducting the excess current away from the protected circuit. This energy absorption prevents damage to components that might otherwise be unable to handle such high-energy transients.
Reliability: TVS diodes are rugged components that can handle multiple transient events without degradation. This makes them a reliable choice for long-term circuit protection.
TVS diodes can be used in various electronic systems, including power supplies, communication equipment, data lines, automotive electronics, and more. When designing a circuit, it's important to select TVS diodes with appropriate breakdown voltage and energy-handling capabilities to match the protection requirements of the components being safeguarded.