I. Introduction to TVS
Transient voltage suppressor (TVS) diodes are protection devices that are typically used in power supply circuits to provide immunity to electrostatic discharge (ESD) and voltage surges.
A typical process for dealing with overvoltage in a circuit is to connect these protection devices in parallel with the power supply circuit so that they can protect the system in the event of a voltage surge. Under normal voltage conditions, the TVS diode operates as if it were open circuit. When the normal voltage is exceeded, the TVS diode junction conducts, causing the overvoltage to be diverted from the safety circuit and the current is then shunted through the clamping diode.
Transient voltage suppression diodes are mainly used to protect semiconductors in circuits and sensitive devices, but also to protect secondary power and signal circuits.
Due to their responsiveness, precise voltage, low clamp voltage and many other advantages, TVS diodes are suitable for protecting devices in extremely important areas such as aerospace, defence, medical and telecommunications.
II.Three main applications for TVS in complex circuits
TVS diodes provide protection for your circuits with a wide range of different current ratings and their protection capability increases with junction area, making it easier for them to absorb higher transient currents. They are specifically designed to suppress transient voltages with different currents. In addition to this advantage, you should also consider choosing TVS semiconductors to protect your complex circuitry.
1. Ability to protect circuit systems from overvoltage and overcurrent
TVS diodes work consistently to protect your circuit from heat during operation. By reducing any transient operating voltages of semiconductors and ICs, the diodes help to reduce the amount of heat generated and extend the life of the circuit. Overvoltage events (e.g. voltage spikes) can occur when the voltage in a circuit is higher than its design limit range, resulting in surges and considerable damage to the device. In such cases, TVS diodes primarily act as overvoltage protection to prevent damage to electronic components and electronic discharge.
2. They are used as voltage clamps to limit transient overvoltages
TVS diodes clamp transient voltages to reduce the amplitude of transients in circuit systems. As a clamping device that limits the voltage to a fixed level, the clamping diode starts clamping as soon as the current threshold voltage increases above a set limit. The diode absorbs excess voltage to protect the circuit, and when the induced voltage exceeds the avalanche breakdown voltage, the TVS diode absorbs the excess energy of the overvoltage. When the overvoltage drops to normal or below a preset voltage threshold level, the diode will return to non-conducting mode.
3. Raising the amplitude to the most controllable level
Protection devices must act quickly to control the current and voltage in a circuit. TVS semiconductors respond very quickly to stimuli to control amplitude. The reason for this is that they are solid-state diodes that absorb the sudden or transient effects of overvoltage by regulating amplitude and bringing it to a safe level. They provide extensive protection in a safe operating area to provide fast protection against excessive voltages and currents. These diodes are an essential part of the basic semiconductor component protection devices to limit the amplitude and protect the circuit.
While reliable protection of circuits in environments characterised by the presence of hot-swappable interfaces and lightning strikes is essential, surge protection is best achieved by using TVS semiconductors to clamp overvoltages to a protected level at the input of the circuit system. It is important to select the right TVS device for a given electrical application. The user or electrical engineer needs to be carefully aware of the different functions offered by a particular type of transient voltage device. Careful device selection can help to enhance the functionality of the protection device.
