Japan's central bank did it in January. The European Central Bank took the plunge in 2014. And the U.S. may need to drop interest rates into negative territory, if the steam runs out of our seven-year recovery

Going negative is often portrayed as a frantic effort by central bankers to simulate demand and ward off recession. But former Federal Reserve Chairman Ben Bernanke doesn't think so. In a blog post on Friday for the centrist Brookings Institution, the former fed chairman, who presided over the central bank during the financial crisis, says fears about negative interest rates are overblown.

"It's also possible that a new round of [quantitative easing] might be less helpful than before," Bernanke writes. "For these reasons, before undertaking new QE, the Fed might want to consider other options, [and] negative interest rates are one possibility."

That may be a bitter pill for small business owners to swallow, as negative interest rates might seem to penalize them--and everyone else-- for saving. But Bernanke says there's a method to the madness.

The U.S. economy is relatively healthy, with a GDP growing at about 2 percent annually and inflation not a threat. But Bernanke says there's a strong likelihood that global weakness will become a drag on the U.S. economy.

And while the Fed tweaked its federal funds rate upward by 25 basis points in December, that may not give current chair Janet Yellen enough room to maneuver if the economy stalls in the months ahead.

Negative interest rates may represent a middle course between no action at all if the economy turns south again, and more active lever-pulling known as quantitative easing, Bernanke writes.

For those of you who need a refresher, the Fed embarked on a path of quantitative easing during the financial crisis. It was a multi-pronged, multi-year program that involved reducing interest rates,  buying up longer-term treasuries,  and printing money to ensure liquidity and stimulate lending.  Equity investors benefitted because the policy steered money into riskier investments such as the stock market 

An interest rate of -0.50 percent or more would trickle through the economy in a similar way, Bernanke says, but essentially without all the fuss, and political volatility, of a big QE program.

While fears that businesses would stash cash outside of bank accounts appear to be overblown, the chief problem with negative interest rates--and it's perhaps a significant one for business owners who save large amounts of cash-- has to do with money market funds. Such funds are guaranteed never to fall below the dollar amount initially invested. Yet negative interest rates could put unsustainable pressure on many funds, Bernanke writes.

Some financial experts took issue with Bernanke's overly rosy portrayal of the way negative rates might work. While bank lending to businesses might loosen and loan rates drop, the economic backdrop that require negative rates would be one of recession, and potentially recession with deflation, says Drew Nordlicht, partner and managing director of Hightower Advisors, San Diego. The firm manages $25 billion in assets for venture capitalists, private equity fund managers, chief executives, and entrepreneurs

"It is very important to understand that negative interest rates are an extreme policy measure," Nordlicht says.