1 Features

• High-efficiency half-bridge transformer driver

• Ultra-low EMI with low interwinding capacitance

• Smaller and lower-cost transformer

– Programmable frequency: 0.1 MHz to 1.2 MHz

• Wide input voltage range: 9 V to 34 V

– 9 W from 34-V input

– 6 W from 24-V input

– 4 W from 15-V input

• Automatic dead-time adjustment with maximum

dead-time programming

• External clock synchronization for low noise

• Robust protection features

– Undervoltage lockout (UVLO)

– Programmable over-current protection (OCP)

– Input overvoltage protection (OVP)

– Over temperature protection (TSD)

– Integrated soft-start to reduce in-rush current

– External disable function with fault-code output

• AEC-Q100 qualified for automotive applications:

– Temperature grade 1: –40°C to +125°C, TA

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• 8-Pin DGN package with thermal pad

2 Applications

• Automotive traction inverter & motor control

• Automotive on-board charger (OBC)

• Automotive DC/DC converter

• EV charging station, DC fast charging station

• UPS and solar inverters

• Industrial motors, elevators and escalators

• GaN, IGBT and SiC gate transformer driver bias

supply

3 Description

The UCC25800-Q1 ultra-low EMI transformer driver

integrates the switching power stage, the control, and

the protection circuits to simplify isolated bias supply

designs. It allows the design to utilize a transformer

with higher leakage inductance, but much smaller

parasitic primary-to-secondary capacitance. This lowcapacitance

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 the isolated

bias supply 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,

further 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 transformer driver can achieve a 6-W

design with 24-V input, and up to 9-W from 34-V

input. With a fixed input voltage, the open-loop control

also helps the output regulation to remain ±5 when

the load is above 10.

The programmable overcurrent protection (OCP)

allows flexibility on the power stage design to

minimize the transformer size. The protection features

such as adjustable OCP, input OVP, TSD and the

protection from pin faults ensure robust operation.

A fixed 1.5-ms soft-start period reduces the inrush

current during start-up and fault recovery.

The transformer driver also provides a dedicated

multi-function pin for external disabling, and fault code

reporting. The fault code reporting sends the fault

code once the bias supply is in the protection mode.

The UCC25800-Q1 transformer driver is offered in an

8-pin DGN package with the thermal pad to enhance

its thermal handling capability.