Low-emission 36-V push-pull transformer driver with duty cycle control for isolated power supplies

The SN6507 is a high voltage, high frequency push-pull transformer driver providing isolated power in a small solution size. The device comes with the push-pull topology’s benefits of simplicity, low EMI, and flux cancellation to prevent transformer saturation. Further space savings are achieved through duty-cycle control, which reduces component count for wide-input ranges, and by selecting a high switching frequency, reducing the size of the transformer.

The device integrates a controller and two 0.5-A NMOS power switches that switch out of phase. Its input operating range is programmed with precision undervoltage lockouts. The device is protected from fault conditions by over-current protection (OCP), adjustable under-voltage lockout (UVLO), over voltage lockout (OVLO), thermal shutdown (TSD), and break-before-make circuitry.

The programmable Soft Start (SS) minimizes inrush currents and provides power supply sequencing for critical power up requirements. Spread Spectrum Clocking (SSC) and pin-configurable Slew Rate Control (SRC) further reduces radiated and conducted emissions for ultra-low EMI requirements.

The SN6507 is available in a 10-pin HVSSOP DGQ package. The device operation is characterized for a temperature range from –55°C to 125°C.