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Diode is a kind of equipment with two electrodes in electronic components, which only allows the current to pass through in a single direction, and many uses use its rectifier function. The directionality of current in most diodes is generally called "rectifying". The most common function of diodes is to allow the current to pass in a single direction (called forward bias) and block it in reverse direction (called reverse bias). So diodes can be thought of as electronic check valves.
Highlights
Diode function:
Diode is one of the most common electronic components. Its biggest feature is single direction conduction, that is, the current can only pass through one direction of the diode. The diode functions include rectifier circuit, detection circuit, voltage stabilizing circuit, various modulation lines, mainly composed of diodes.
Performance parameters of single and two surgical tube module
It is used as the technical index to indicate the performance and application scope of the second surgical tube module, which is called the parameters of the second surgical tube module. Different types of two tube modules have different performance parameters.
1. Maximum rectified current
It refers to the maximum forward current allowed by the two transistor module during long-term continuous operation, which is related to the PN junction area and external heat removal. When the current passes through the tube, the tube core will be heated and the temperature will rise. When the temperature exceeds the allowable limit (between 141 for silicon tube and 90 for germanium tube), the tube core will be overheated and damaged. Therefore, under the condition of heat removal, the maximum rectifier current of the two tube module should not be exceeded during operation. For example, the common in4o01-4007 germanium diode module has a rated forward operating current of 1a.
2. Maximum reverse operating voltage
When the reverse working voltage on both sides of the second surgical tube module reaches a certain value, the tube will break down and lose the ability of single guiding electricity. In order to ensure the operation safety, the maximum reverse working voltage is required. For example, the reverse withstand voltage of in4o01 secondary tube module is 50V, and that of IN4007 is 1000V.
3. Reverse current
It refers to the reverse current of the second surgical tube module under the action of the required temperature and maximum reverse working voltage. The smaller the reverse current, the better the unidirectional conductivity of the tube. It should be noted that the reverse current is closely related to the temperature, and the reverse current increases by one time for every 10 ℃ rise in temperature. For example, if the reverse current of 2ap1 germanium diode module is 250ua at 25 ℃, when the temperature rises to 35 ℃, the reverse current will rise to 500uA, and so on. At 75 ℃, the reverse current of 2ap1 germanium diode module has reached 8Ma, which not only loses unidirectional conductivity, but also damages the tube due to overheating. For another example, the reverse current of 2cp10 silicon diode module is only 5ua at 25 ℃ and 160ua at 75 ℃. Therefore, the silicon diode module has better stability than the germanium diode module at high temperature.
4. Dynamic resistance Rd
The ratio of the variation of the operating voltage near the static operating point Q of the diode characteristic curve to the variation of the corresponding current.
Details
Working principle of diode module
The crystal diode is a PN junction composed of p-type semiconductor and n-type semiconductor. The space charge layer is formed on both sides of the interface and a self built electric field is built. When there is no additional voltage, the diffusion current caused by the carrier concentration difference on both sides of the PN junction is equal to the drift current caused by the self built electric field, so it is in the state of electric balance.
When there is a positive voltage bias, the mutual suppression function of external electric field and self built electric field increases the diffusion current of carriers, resulting in the positive current. When there is a reverse voltage bias, the external electric field and the self built electric field are further strengthened to form the reverse saturation current I0 which is independent of the reverse bias voltage in the corresponding reverse voltage range.
When the additional reverse voltage is high enough, the electric field strength in the space charge layer of PN junction exceeds the critical value, forming the multiplication of carriers, forming a large number of electron hole pairs, forming a large number of reverse breakdown current, which is called diode breakdown phenomenon. The reverse breakdown of PN junction can be divided into zener breakdown and avalanche breakdown.
The above is the introduction of the single diode module by the diode module manufacturer semipower. Semipower is a power semiconductor power module supplier specialized in power electronics technology. It supplies the formulation, production, processing and production of semiconductor power modules for various enterprises and companies. In addition, it also supplies the processing projects of supplied materials or OEM for various enterprises. The main products are: IGBT module, thyristor (thyristor) module, ultra fast recovery epitaxial diode module, single-phase rectifier bridge module, three-phase rectifier bridge module, rectifier diode module, Schottky diode power module and other power semiconductor electronic components.
