UCC25800-Q1 Ultra-Low EMI Transformer Driver

Texas Instruments' UCC25800-Q1 ultra-low EMI transformer driver integrates a switching power stage, a control, and protection circuits to simplify isolated bias supply designs. This allows the design to utilize a transformer with higher leakage inductance and smaller parasitic primary-to-secondary capacitance. The low-capacitance transformer design enables an order of magnitude reduction in the common-mode current injection through the bias transformer. This makes the transformer driver an ideal solution for isolated bias supplies in various automotive applications to minimize the EMI noise caused by the high-speed switching devices. The soft-switching feature further reduces the EMI noise.

The transformer driver has a programmable frequency range of 100 kHz to 1.2 MHz. This high switching frequency reduces the transformer size and footprint, as well as the overall cost of the bias supply. The integrated SYNC function allows the system bias supplies to synchronize with an external clock signal reducing the system level noise. The dead-time adjusts automatically to minimize the conduction loss and simplify the design. The programmable maximum dead-time ensures power stage design flexibility. With the integrated, low-resistance switching power stage, the UCC25800-Q1 can achieve a 6 W design with a 24 V input and up to 9 W from a 34 V input. With a fixed input voltage, the open-loop control helps the output regulation to remain at ±5% when the load is above 10%. The programmable overcurrent protection (OCP) allows flexibility on the power stage design to minimize the transformer size.

Robust operation is ensured with protection features including adjustable OCP, input overvoltage protection (OVP), overtemperature protection (TSD), and protection from pin faults. The fixed 1.5 ms soft-start period reduces the inrush current during start-up and fault recovery. The transformer driver provides a dedicated multi-function pin for external disabling and fault-code reporting. Fault-code reporting sends the fault code once the bias supply is in protection mode. The UCC25800-Q1 transformer driver is offered in an 8-pin DGN package with a thermal pad to enhance the thermal handling capability.