Carefully chosen components simplify the development of modern, energy-efficient power supplies. However, achieving optimal performance requires parts specifically engineered for such applications—exactly what Diotec Semiconductor provides.
Below is a cross-sectional overview of Diotec products available through the TME offering, focused mainly on power supply applications and related functions such as power factor correction, pulse generation, and surge protection. These solutions help build highly efficient devices that meet the growing demands of today’s energy and power electronics industry.
Active inrush current limiting
The diagram below presents a simple yet energy-efficient method of limiting inrush current in a switching power supply. After the mains voltage is applied, a resistor limits the inrush current to a level suitable for the input bridge and the capacitor in the DC circuit. When the capacitor voltage reaches approx. 90% of the DC voltage in the circuit, a Schmitt trigger turns on the MOSFET transistor (the DC voltage is superimposed on the AC component, and the design must account for these fluctuations). The activated MOSFET bypasses the resistor, significantly reducing power losses. The Schmitt trigger output must be capable of supplying the required MOSFET gate charge current, while a TVS diode protects the gate from excessive voltage.
In the event of a mains power loss and when the capacitor voltage drops below 90% of the minimum DC voltage, the MOSFET also turns off. When power returns, the resistor again limits the inrush current. As a result, the presented circuit is safer than simple inrush current limiting using an NTC thermistor, which may require several minutes to cool down and regain high resistance.
Circuit diagram of an automatic inrush current limiting circuit in a power supply.
Below we present an overview of the Diotec range, which includes all the basic semiconductors used in this example circuit.
Rectifier bridges
When designing power supplies connected directly to the mains, important parameters of rectifier bridges include efficiency and the ability to maintain low temperature even under significant load. The Diotec Semiconductor range includes SMD and THT components designed for single- and three-phase inputs.
- Maximum reverse voltage up to 3kV;
- forward current up to 50A (450A surge);
- available in packages suitable for heatsink mounting;
- versions in standard formats for through-hole and surface mounting.
Rectifier diodes
The Diotec rectifier diode range includes both general-purpose components and specialized products with specific properties. Examples of the latter include diodes resistant to avalanche breakdown, used in high-voltage circuits exposed to disturbances from the power line. In power supplies, they are used when supplying energy to a PWM controller or switching converter transistors (bootstrap). Diotec also manufactures ultrafast diodes intended for power factor correction circuits (PFC, Power Factor Correction).
- Rectifier diodes with forward current up to 80A/300A (1.45kA surge);
- reverse voltage tolerance up to 24kV;
- availability of THT and SMD models, as well as screw-mounted versions;
- special variants for the automotive industry;
- dual structures (including series configurations);
- low leakage currents (down to 0.1µA).
Other diodes
It is also worth mentioning special diodes used in various types of power supplies, primarily in protection circuits. These include TVS diodes, i.e. surge protection devices used for clamping high-energy transients to ground. Another specialized type are CRD components (Current Regulator Diode), which allow obtaining a precisely defined current, e.g. for powering LED indicators, or even more complex semiconductor systems (microcontrollers), battery charging controllers, etc.
Zener diodes available in the Diotec range Zener diodes come in a wide range of parameters and formats:
- Zener voltage from 0.71V to 200V;
- power dissipation from 0.2W to 5W;
- SMD and THT versions, single and dual;
- availability of high-precision versions (±2%);
- models certified for automotive applications.
Voltage regulators
The Diotec portfolio includes not only diodes – the manufacturer also offers a wide selection of complementary semiconductor devices, such as voltage regulators. Both fixed-output (non-adjustable) and adjustable (linear, configured using external components) versions are available. An important part of the range are LDO regulators (Low Dropout), which maintain stable output voltage even when the input voltage is only slightly higher than the output.
- Regulators with output voltage from -24V to 24V DC and current capability up to 3A;
- input voltage range from -27V to 60V DC (across the entire range);
- selection of classic THT (TO92) and SMT (SOT23) packages;
- minimized voltage drop (down to 20mV);
- wide operating temperature ranges (e.g. -55…150°C).
MOSFET transistors
Of course, the Diotec portfolio also includes MOSFET transistors designed for use in switching power supplies. The key features of these components include:
- versions with N- or P-channel and multi-channel;
- operation with drain-source voltage up to 1.7kV and drain current up to 374A;
- power dissipation up to 750W;
- versions manufactured using silicon carbide (SiC) technology, specially protected against electrostatic discharge, designed for automotive applications.
Other transistors
Diotec also offers other transistors used in power supplies and inverters, primarily bipolar and IGBT types. Their general characteristics include:
- collector-emitter voltage up to 700V AC for bipolar transistors and 1.35kV for IGBTs;
- operating frequency up to 600MHz (bipolar), with switching times reduced to 13.5ns (turn-on) and 130ns (turn-off) for IGBTs;
- collector current for IGBTs up to 100A;
- availability in THT and SMT packages.
