 If you are searching for a simple solution that will increase the efficiency of your application and manage its in-rush current, we have what you need. It is the STEVAL SCR0021 reference design with SCRs. Improvement of power density and reliability is a major trend for power supply manufacturers and moving from the passive and mechanical parts to silicon devices is a key enabler. At the application startup, the in-rush current can be 10 times higher than the nominal current. The IC standard requires its limitation to avoid undesirable effects such as power electronics components damage, circuit breaker or digital control tripping and AC network disturbances caused by voltage fluctuations. The STEVAL SCR0021 reference design introduces a simple and innovative AC to DC front end circuit using SCRs with a gate driver. This enables you to perform an in-rush current limitation in any converter with input bridge rectifier topologies. There are two methods to limit in-rush current. The first is a bypass method which adds a serial resistor or NTC to charge the converter capacitor and this resistor being bypassed once charge is done. The second way uses a smart method and active switches such as the SCR to smoothly limit the capacitor charge. The new ST board performs both methods with a simple drive circuitry for the two power SCRs and the bridge rectifier being controlled by a single signal out of the MCU. A mechanical relay might need to be fully removed due to its inherent drawbacks such as EMI or acoustic noise, aging or the risk of it switching due to vibrations. The STEVAL SCR0021 can control in-rush current only using the smart in-rush method I have described. In this mode of operation the board will not only avoid all previously mentioned drawbacks of mechanical relays but also will improve charge time of the capacitor and will increase overall system efficiency for applications up to 1 kW. STEVAL has a large portfolio of theistors and triacs up to 1200 volts which limits the in-rush current in many different technologies. If you are searching for different reference designs for in-rush current limitation please visit st.com. There you can find our reference designs for in-rush current limitation with different power ranges starting from 0.8 kW up to 7 kW. Thanks for watching and talk to you soon.