If the fast recovery diode circuit fails, can it be replaced with a rectifier diode? What is the difference between the two? Consider parameter requirements and costs.

The fast recovery rectifier diode belongs to the high-frequency rectifier diode in the rectifier diode, which is suitable for the high frequency circuit occasions. For the low frequency, such as the power frequency below 50HZ, it is better to use the common rectifier diode.

Fast recovery diode is often used as rectifier diode in inverter circuit with high frequency. However, due to the low frequency of the rectifier circuit, only the withstand voltage is required. As long as the withstand voltage can be met, it can certainly be substituted. In addition, the fast recovery diode can also be used for rectification. That is, in the secondary rectification part of the switching power supply, due to the high frequency, only the fast recovery diode can be used for rectification. Otherwise, the overall efficiency of the power supply will be reduced due to too much diode loss, and in serious cases, the diode will be burned. In addition, the cost is involved. The price of fast recovery diode is much more expensive than that of rectifier diode. The higher the withstand voltage is, the more expensive it is. Therefore, it is generally impossible to recover the second-generation tube quickly.

The reason why it is called fast recovery diode is that ordinary rectifier diode generally works at low frequency (such as 50Hz mains frequency), and its operating frequency is lower than 3kHz. When the operating frequency is tens to hundreds of kHz, the time of forward and reverse voltage changes is slower than the recovery time, and ordinary rectifier diode cannot normally achieve unidirectional conduction. At this time, it is necessary to use fast recovery rectifier diode.

The fast recovery diode is characterized by its short recovery time, which makes it suitable for high-frequency (such as the line frequency in TV) rectification. The fast recovery diode has an important parameter that determines its performance - reverse recovery time. The reverse recovery time is defined as the time required for the diode to rapidly switch from the forward conduction state to the cut-off state, from the time when the output pulse drops to the zero line, to the time when the reverse power supply recovers to 10% of the maximum reverse current, usually represented by the symbol trr. The trr of ordinary fast recovery rectifier diode is hundreds of nanoseconds (10-9s), and that of ultra fast recovery diode is tens of nanoseconds. The smaller the Trr, the higher the operating frequency of the fast recovery diode.