Singer Cee Lo Green pleaded not guilty Monday to a felony charge of furnishing Ecstasy to a woman while dining at a downtown L.A. restaurant, but prosecutors declined to charge him with raping the woman while she was intoxicated, citing insufficient evidence.

The 38-year-old judge on NBC's "The Voice," whose real name is Thomas DeCarlo Calloway, appeared before an L.A. County Superior Court judge as his attorney, Blair Berk, entered his plea and waived his right to a speedy trial.

Although he avoided the more serious rape charge, Green could receive up to four years in prison if convicted of giving the 33-year-old woman Ecstasy, a drug also known as Molly, at the Wokcano restaurant in July 2012.

Sources familiar with the investigation said Green allegedly acknowledged providing the woman the drug in a documented telephone call after the incident.

The singer who found fame with the song "Forget You" agreed to surrender to the Los Angeles Police Department for booking within seven days. A bond agent immediately appeared to post $30,000 bail to release Green.

The singer, dressed in black topped with a black, cape-like robe and dark metal-rimmed glasses, sat in the front row of the court with his girlfriend and occasionally spoke to Berk and his other lawyer, former U.S. Atty. Thomas O'Brien. The usually talkative Green, known for his colorful outfits, said only "Yes, your honor" during the court proceedings, in answer to whether he would surrender within seven days.

Before court, Berk said Green was "pleased" with the prosecutors' decision not to file the rape charge in what Berk described as "consensual relations."

"Cee Lo had faith that if true facts were known, the district attorney would reject those charges," Berk said of the sex assault case. "As it relates to the one charge of furnishing or sharing Ecstasy, Mr. Green will responsibly address that matter in a court of law, but not comment on it further out of respect for the process."

A Los Angeles Police Department investigation into the singer began shortly afterthe woman reported to authorities that he put the drug in her drink as they dined together. The woman told investigators she woke up to find herself naked in a bed with the singer in her hotel room.

But after two rounds of investigations by the LAPD's Robbery-Homicide Division, prosecutors declined to file sex-related charges against Green, citing a lack of evidence.

"We are pleased that the Los Angeles County district attorney has completed its investigation and concluded that the evidence did not support the false and unfounded claim made over a year ago," Berk said Monday.

richard.winton@latimes.com