For high-power switching circuits, the gate of the power transistors needs to be driven to both a positive and negative isolated voltage for reliable, low-loss, high-voltage switching. The positive voltage needs to be chosen for full enhancement without exceeding the maximum limit, and the negative voltage needs to be chosen to reliably switch the transistor off (even with induced voltage transients arising from high di/dt switching). The optimal asymmetric gate drive voltage levels are both transistor-type dependent (e.g. IGBT: +15/-9V, MOSFET: +20/-5V, SiC: +18/-4V, GaN: +10/-1V) and manufacturer/generation dependent (e.g. SiC Gen1: +20/-5, SiC Gen 2: +18/-3V, Sic Gen 3: +15/-4V, etc.).
The R24C2T25 meets a strong market need for a regulated, isolated, adjustable output gate driver power supply so that power engineers can create reliable, low-loss power stages using whichever transistor technology, type, or manufacturer they choose. If, in the future, a new transistor generation is released with different optimal gate drive voltages, the designer need only adjust the set resistors to the new voltage levels. The R24C2T25 can generate independently regulated output voltages in the range of +2.2 to +22.5V and from -2.5V to -22.5V, meaning that any existing and even not-yet-released transistor can be properly driven.
The isolated gate driver power supply common pin is connected to the switching node on high-side driver applications, so the R24C2T25 has a high CMTI of 150kV/µs and 3kVrms/1 min isolation with a working voltage rating of 850VAC. Enable and power good pins can be used to sequence the start-up so that the power stage only starts once the output supply voltages have stabilized, avoiding “first pulse” failures.
As the gate driver power supply is often placed near hot power components on the PCB, a high ambient operating temperature is to be expected. The R24C2T25 comes in a low profile (3.5mm) SSOP SMD package and delivers full power up to +85°C ambient, with operation up to +125°C with derating. For outdoor, off-highway, or automotive applications, cold operation is down to -40°C. The outputs are fully protected against continuous short circuit, overload, and over-temperature faults, and the power supply has soft start, under-voltage, and over-voltage lockout functions for high power switching reliability. The internal transformer driver circuit operates with ZVS and spread-spectrum frequency dithering to minimize radiated EMI.
Applications include EV, hybrid and power train systems, EV charging stations, industrial inverters, motor controllers, and renewable energy uses such as photovoltaic, wind turbine, ESS, and smart grid infrastructure projects.