10.2.1 Diode Selection

LMG341xR070 has no reverse-recovery charge and little output charge. Hard-switched circuits using LMG341xR070 also exhibit high voltage slew rates. A compatible bootstrap diode must exhibit low output charge and, if used in a hard-switching circuit, very low reverse-recovery charge.

For soft-switching applications, the MCC UFM15PL ultra-fast silicon diode can be used. The output charge of 2.7 nC is small in comparison with the switching transistors, so it will have little influence on switching performance. In a hard-switching application, the reverse recovery charge of the silicon diode may contribute an additional loss to the circuit.

For hard-switched applications, a silicon carbide diode can be used to avoid reverse-recovery effects. The Cree C3D1P7060Q SiC diode has an output charge of 4.5 nC and a reverse recovery charge of about 5 nC. There will be some losses using this diode due to the output charge, but these will not dominate the switching stage’s losses.