Roku is in advanced discussions to raise at least $200 million in new funding at a post-money valuation of approximately $1.5 billion, according to sources familiar with the situation. The company received a term sheet this week. The round will be led by U.S.-based investors, one source says, but “not standard Silicon Valley venture firms.” The total raise could go above $200 million because a portion of the deal may include secondary sales by existing investors.

Based in Los Gatos, Calif., Roku makes connected TV hardware. The startup has raised $210 million in funding so far from investors including News Corp, Fidelity Investments, Menlo Ventures, Hearst Ventures, Viacom, Fox Networks, and Netflix.

Roku competes in a crowded market; Google, Amazon, Apple and the cable providers all offer their own connected TV products. The company is known as “Switzerland” in the market – a neutral player — because it doesn’t have its own content to push users toward. A Roku representative declined to comment.

This article has been updated to incude Roku’s comment.