SUNMATE Replacement principle of rectifier diode — SUNMATE
Replacement principle of rectifier diode
What is a rectifier diode
A semiconductor device that converts alternating current energy into direct current. Rectifier diodes are widely used in various power supply rectifier circuits. When selecting rectifier diodes, we mainly consider its parameters such as reverse working voltage VR, average rectifier current if, reverse working current IR, working frequency FM and reverse recovery time TRR.
Principle of rectifier diode replacement
The power supply has both low frequency and high frequency. For the series regulated power supply, it is a power supply that obtains a stable output voltage by continuously adjusting the voltage drop of the power tube when the input or output changes. When the power tube works, it is in the linear amplification state. This circuit does not have high requirements for the reverse recovery time of the rectifier diode. Therefore, as long as the rectifier diode of this power supply meets the rectifier current. The basic requirements such as reverse working voltage and reverse working current are OK, such as 1n400x series diodes we often use.
However, for the switching regulated power supply, it obtains a stable output voltage by adjusting the on or off of the power tube. In that case, the regulating tube works in the saturated on state. Its rectifier circuit has a relatively high working frequency for the rectifier diode used. In addition, the reverse recovery time is also required to be short. At this time, it is necessary to select fast recovery diode or even Schottky diode.
Therefore, to sum up, several principles can be considered for rectifier diode replacement:
① The rectifier diode with large average rectifier current can replace the diode with small rectifier current, otherwise it will not work;
② The rectifier diode with high reverse working voltage can replace the rectifier diode with low reverse voltage, otherwise it will not work;
③ The rectifier diode with high working frequency can replace the rectifier diode with low working frequency, and vice versa