Trisil
Encyclopedia
A Trisil is trade name for a thyristor surge protection device, an electronic component designed to protect electronic circuits against overvoltage
. Unlike a transient voltage suppression diode
s, such as Transil, it acts as a crowbar
device, switching on when the voltage on it exceeds its breakover voltage.
without gate. The behavior of a Trisil is similar to a SIDAC, but unlike SIDAC, Trisil devices are commonly used to protect circuits from overvoltage. They act faster and can handle more current. In 1982, the only manufacturer was Thomson SA
; a successor company, ST Microelectronics continues to make the devices.
This type of crowbar protector is widely used for protecting telecom equipment from lightning-induced transients and induced currents from power lines. Other manufacturers of this type of device include Bourns (TISP) and Littelfuse
(SIDACtor). Rather than using the natural breakdown voltage of the device, an extra region is fabricated within the device to form a Zener diode
. This allows a much tighter control of the breakdown voltage.
It is also possible to make gated versions of this type of protector. In this case, the gate is connected to the telecom circuit power supply (via a diode or transistor) so that the device will crowbar if the transient exceeds the power supply voltage. The main advantage of this configuration is that the protection voltage tracks the power supply, thus eliminating the problem of selecting a particular breakdown voltage for the protection circuit.
Overvoltage
When the voltage in a circuit or part of it is raised above its upper design limit, this is known as overvoltage. The conditions may be hazardous...
. Unlike a transient voltage suppression diode
Transient voltage suppression diode
A transient-voltage-suppression diode is an electronic component used to protect sensitive electronics from voltage spikes induced on connected wires....
s, such as Transil, it acts as a crowbar
Crowbar (circuit)
A crowbar circuit is an electrical circuit used to prevent an overvoltage condition of a power supply unit from damaging the circuits attached to the power supply. It operates by putting a short circuit or low resistance path across the voltage source, much as if one dropped a tool of the same name...
device, switching on when the voltage on it exceeds its breakover voltage.
Overview
A Trisil is bidirectional, behaving the same way in both directions. It is principally a voltage-controlled triacTriac
Triac may refer to:* TRIAC , an electronics component* Triac , a green vehicle* Tiratricol, a common thyroid hormone analogue used for treating thyroid hormone resistance syndrome...
without gate. The behavior of a Trisil is similar to a SIDAC, but unlike SIDAC, Trisil devices are commonly used to protect circuits from overvoltage. They act faster and can handle more current. In 1982, the only manufacturer was Thomson SA
Thomson SA
Technicolor SA , formerly Thomson SA and Thomson Multimedia, is a French international provider of solutions for the creation, management, post-production, delivery and access of video, for the Communication, Media and Entertainment industries. Technicolor’s headquarters are located in Issy les...
; a successor company, ST Microelectronics continues to make the devices.
This type of crowbar protector is widely used for protecting telecom equipment from lightning-induced transients and induced currents from power lines. Other manufacturers of this type of device include Bourns (TISP) and Littelfuse
Littelfuse
Littelfuse Inc. is an American multinational electronics manufacturing company based in Chicago, Illinois.Littelfuse, Inc. provides circuit protection products to companies in the areas of over-voltage, over-current and integrated technologies in the automotive, electronics, electrical and...
(SIDACtor). Rather than using the natural breakdown voltage of the device, an extra region is fabricated within the device to form a Zener diode
Zener diode
A Zener diode is a special kind of diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, "Zener knee voltage" or "Zener...
. This allows a much tighter control of the breakdown voltage.
It is also possible to make gated versions of this type of protector. In this case, the gate is connected to the telecom circuit power supply (via a diode or transistor) so that the device will crowbar if the transient exceeds the power supply voltage. The main advantage of this configuration is that the protection voltage tracks the power supply, thus eliminating the problem of selecting a particular breakdown voltage for the protection circuit.