Rectifiers are the core components in electronic circuits that enable AC to DC conversion. Their classification can be systematically based on material properties, structural design, and functional applications. The specific classifications are as follows:
1、 Divided by material type
Silicon rectifier diode
Silicon materials have become the mainstream choice due to their high voltage resistance (up to several thousand volts), good thermal stability (operating temperature of 55 ℃ to 150 ℃), and low leakage current characteristics. Typical models such as 1N4007 (1A/1000V) are widely used in power frequency rectification scenarios such as power adapters and chargers.
Germanium rectifier diode
The conduction voltage of germanium material decreases (about 0.3V), but the reverse withstand voltage generally does not exceed 100V, and the leakage current is relatively high at high temperatures. Early used in low-voltage radio detection circuits, it is now mostly replaced by silicon devices.
2、 Divided by structural process
Surface contact diode
Adopting a structure with a larger PN junction area allows for the passage of several amperes of current, with a reverse recovery time of approximately microseconds. 1N5408 (3A/1000V) is commonly used in power frequency rectifier bridges and is suitable for filtering the secondary side of transformers.
Schottky barrier diode
By using metal semiconductor contacts to form potential barriers, the conduction voltage is reduced to 0.150.45V, and the reverse recovery time is extremely short (nanosecond level). The MBR series (such as MBR20100CT) is widely used for output rectification of switching power supplies, which can significantly reduce high-frequency losses.
3、 Divided by frequency characteristics
Power frequency rectifier diode
Designed for 50/60Hz, emphasizing high voltage resistance and high current capability. For example, the GBU808 rectifier bridge can handle 8A current at 800V voltage and is used for AC motor drive power supply.
High-frequency rectifier diode
Fast Recovery Diode (FRD): Reverse recovery time of 50500ns, such as UF4007 used in the frequency converter freewheeling circuit.
Ultra fast recovery diode: recovery time<50ns, FFH30S60S is suitable for IGBT drive protection.
Schottky diode: suitable for MHz switching frequency, such as SS56 used for synchronous rectification in DCDC converters.
4、 Divided by special functions
Avalanche rectifier diode
By precisely controlling the doping concentration, it exhibits controllable avalanche effect during reverse breakdown, such as the STTH series, which is suitable for scenarios with voltage spikes such as welding machines.
Bridge rectifier stack
Integrating four diodes to form a full bridge structure, such as KBPC5010, can simplify circuit layout and directly handle 220VAC input rectification.
High voltage stack diode
Adopting multi chip series packaging, the withstand voltage can reach tens of kV, and typical applications include X-ray machine high-voltage generators.
5、 Divided by packaging form
Axial lead packaging
DO41 (1N400x), DO15 (1N540x) and other direct insertion packages are convenient for manual welding and maintenance.
Surface mount packaging
SMA (1A), SMB (2A), DPAK (5A) and other surface mount models are suitable for automated production, such as SS14 packaged in SMA, which is commonly used for motherboard power modules.
Key points of technical selection
Voltage margin: The actual peak operating voltage should be less than 70% of the rated VRRM
Current derating: It is recommended that the continuous operating current does not exceed 50% of IF (AV)
Thermal management: Calculate the junction temperature Tj=Ta+Pd × R θ ja to ensure that it does not exceed the limit specified in the specifications
For example, when designing a 12V/5A output switching power supply, MBRB1645 (16A/45V Schottky) can be used for secondary rectification, which reduces conduction loss by 75% compared to silicon diodes at 0.5V voltage drop, significantly improving overall efficiency. High frequency characteristics can also reduce EMI interference, which meets the requirements of modern power supply design.
This classification system progresses layer by layer from physical characteristics to application scenarios, and engineers can accurately select based on specific circuit parameters (voltage, frequency, efficiency requirements, etc.) to achieve an optimized balance between performance and cost.