The Fed's asset-purchase programs, aimed at keeping long-term borrowing costs down and spurring investment, have been criticized overseas for their adverse impact on emerging market currencies.

But the Fed chief, fresh from a grilling from Congress on the potential domestic risks of his quantitative easing measures, countered the rhetoric about "currency wars," though he did not use the term specifically.

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did

In prepared remarks to a group of academics in London, Bernanke said the integrated nature of the global economy meant the whole world benefits from a sturdier U.S. outlook.

"Because stronger growth in each economy confers beneficial spillovers to trading partners, these policies are not 'beggar-thy-neighbor' but rather are positive-sum, 'enrich-thy-neighbor' actions," he aid.

In response to a deep financial crisis and recession, and subsequent weak recovery, the Fed not only lowered overnight interest rates to effectively zero but bought more than $2.5 trillion in mortgage and Treasury securities.

Domestic critics say the central bank's vastly expanded balance sheet, now topping $3.1 trillion, risks future inflation. But Bernanke has noted that inflation is forecast to remain at or below the central bank's 2 percent target for the foreseeable future.

Economic growth, meanwhile, remains more of a question mark, particularly with the combination of sharp spending cuts at home and turbulence in European financial markets casting a pall over some better recent U.S. economic data.

Analysts expect U.S. gross domestic product will expand around 2 percent this year, while Fed officials see 2013 growth between 2.3 percent and 2.7 percent.

"The distinction between monetary policies aimed at domestic objectives and trade-diverting exchange rate devaluations and other protectionist measures is critical," Bernanke said.

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did