High Isolated DC/DC Converters for Gate Drivers

DC/AC inverters are often floated by a few hundred volts above ground. A typical isolation voltage would be at least twice the working voltage. Taking into account the high switching rates to maintain high efficiency and high floating voltages, highly isolated DC/DC converters are needed to power gate drivers. Optocouplers act as an insulator for the control signal, but there is a need for an insulator on the power side. Whether IGBT, Si-MOSFET, SiC MOSFET or GaN, RECOM’s DC/DC converters for gate drivers are simple drop-in modules for a reliable, long-life solution.

RECOM’s DC/DC converters RH, RV, RP, RGZ, RKZ, RxxPxx, and RxxP2xx are specially designed for IGBT driver circuits. Their asymmetric outputs of +15V and -9V makes them ideal to power IGBT drivers, so now just one converter is needed where previously two were required. To meet the requirements of the different IGBT applications, RECOM offers various pin-outs and packages (SIP/DIP).

Switching SiC MOSFETs requires certain turn-on and turn-off voltages to get the maximum performance from the WBG transistor. The RxxP22005D and RKZ-xx2005D series feature asymmetric outputs of +20V and -5V to efficiently and effectively switch the SiC MOSFET. The RxxP21503D series provides asymmetric output voltages of +15 and -3V, which are needed to efficiently switch second generation SiC MOSFETs. The SMD-mounting RA3 series provides three different output voltage combinations to power first, second or third generation SiC devices, along with more current for faster switching.

High slew-rate GaN transistor drivers reach optimal performance switching at +6V from RECOM’s DC/DC converters RP-xx06S and RxxP06S series featuring high isolation voltage and low isolation capacitance. In GaN applications where higher noise and interferences have to be considered, RECOM also offers converters with +9V output which can be split up via a Zener diode to +6V and -3V to provide a negative gate voltage on turn-off ensuring that the gate voltage stays below the turn-on threshold. The RA3 series is SMD-mounting, like many GaN transistor packages, and provides three different output voltages to maximise the performance of different WBG devices, along with offering increased power for faster switching.