Goleta-based Transphorm, the stealthy, Google and Kleiner Perkins Caufield & Byers startup in the energy conversion space, has unveiled its first product today at a conference. The firm said it has created a power diode, based on Gallium Nitride technology, which provides over 99 percent efficiency for DC-to-DC converters. The firm said that its product cuts energy waste by 20 percent, and simplifies design and manufacturing of electrical systems and devices. Transphorm, which is headed by Umesh Mishra, just announced $20M in a Series C funding led by Google Ventures last month. The firm is backed by Google, Kleiner Perkins Caufield and Byers, Foundation Capital, and Lux Capital, and has raised over $38M in funding. The firm's CEO is Umesh Mishra, who was previously a professor at the University of California, Santa Barbara.