TIDUEY6 April 2021
Isolated gate drive power supply for the secondaries of all UCC5870s are designed in a separate board and mounted on the back of gate driver card. This is to reduce contact lengths between power supplies and gate driver secondary circuits. This module is designed using SN6501-Q1 and is based on the HEV/EV Traction Inverter Power Stage with 3 Types of IGBT/SiCBias-Supply Solutions reference design. The chosen secondary voltages are +18 V and -4 V and current rating of about 180mA. The supply can cater to momentary current spike demand using the energy stored in its output capacitor.
The power supply is designed based on a regulated 5 V input with no secondary regulation. It generates a fixed boost secondary voltage. For the given load level of power supplies, secondary regulation is not considered mandatory. The six power supplies are designed on a single board with sufficient spacing between them to ensure safe voltage compliance. A picture of the board is shown in Figure 3-23.
Gate drive power supply module is mounted on the rear side of gate drive board on headers J2, J4_x, J3 and J6. J4_x is a 3 pin connector used that takes in the power supply for each driver. J3 and J6 are non-electric connectors whose only intent is to provide mechanical stability and spacing in the mated position between the gate driver and gate drive power supply boards.