Transient Diode Applications

TVS is mainly used for rapid overvoltage protection of circuit components. It can "absorb" surge signals with power up to several kilowatts. TVS has many advantages such as small size, high power, fast response, no noise, and low price. It is widely used, such as: household appliances; electronic instruments; meters; precision equipment; computer systems; communication equipment; RS232, 485 and CAN And other communication ports; ISDN protection; I/O ports; IC circuit protection; audio and video input; AC and DC power supplies; motor and relay noise suppression and other fields. It can effectively protect against over-voltage surges caused by human operation errors such as lightning and load switches. The following are some typical examples of TVS in circuit applications.

TVS is used in AC circuits. This is an application of bidirectional TVS in AC circuits to protect all components in the rectifier bridge and load. Figure 7 shows that a one-way TVS is connected in parallel to the side of the rectifier to protect the rectifier from breakdown by instantaneous pulses. TVS1 in Figure 8 is a bidirectional TVS tube, which can "absorb" instantaneous large pulses in both positive and negative directions, and clamp the circuit voltage to a predetermined level. This kind of two-way TVS is extremely convenient for AC circuits. It can protect all circuit components after the transformer. Due to the addition of TVS1, the circuit fuse capacity must be increased. TVS2 is also a two-way TVS tube, which can protect the bridge rectifier and subsequent circuit components from overvoltage. Its Vb value and VC value should be compatible with the output voltage of the secondary side of the transformer. TVS3 is a one-way TVS tube, because the voltage applied to it is a rectified DC voltage. TVS3 only protects the load from overvoltage. One or more of the three TVS tubes can be used in the circuit as needed.