TIDUF23 may 2023
As shown in the schematic in Figure 2-4, the UCC14240-Q1 DC/DC converter module operates from a single 24-V (P24V) input and is configured to provide dual, +15 V (VCC2), -4 V (VEE2), 3-kV RMS isolated, bias supply voltage rails to the UCC5880-Q1 isolated gate driver. VCC2 and VEE2 are programmed by resistor dividers R13, R19 and R15, R20 and are tightly regulated to within ±1.3%, providing +15 V and -4 V as recommended by the Wolfspeed XM3, SiC Half-Bridge Module. Startup is initiated when the digital host first provides the enable signal (EN_PS) required to pull the UCC14240-Q1 ENA pin to an active high state, allowing VCC2 and VEE2 to soft-start. The UCC14240-Q1 then provides an active low, LVTTL compatible, power good signal (N_PG), notifying the host that P24V is above the 21-V, UVLO turn-on threshold and VCC2 and VEE2 are above 90% of their set regulation target values (VCC2>13.5 V and VEE2>3.6 V respectively). This connection between the host and UCC14240-Q1 makes sure the UCC5880-Q1, gate driver has sufficient bias voltage present to safely allow inverter switching to begin.