In standard through-hole packages, as for instance TO-220 or TO-247, each lead pad resembles a parasitic inductance. The TO-247 4pin package has an extra Kelvin emitter connection. This 4pin known also as Kelvin emitter terminal, bypasses the emitter lead inductance on the gate control loop, enhancing the IGBT’s switching speed and decreasing the switching energy.
TO-247 4pin package with Kelvin emitter enables faster commutation, improving the switching behaviour of IGBT. Dynamic losses are reduced by 20% in comparison to standard TO-247 package, thus increasing the overall system efficiency and enabling the IGBTs to operate at lower temperature.
The faster the IGBT is able to switch, the bigger the benefit from TO-247 4pin becomes.