Dollar Broadly Weak on Econ Worries  LONDON (Reuters) - The dollar fell to a 7-1/2 month low  against the euro on Wednesday and a three-month trough on the  Swiss franc as a selloff on the back of recent worries about  the U.S. economy and interest rate outlook gained momentum. The  yen came under pressure briefly as Tokyo stocks fell 1.65  percent. But given the export-oriented economy's reliance on  oil, a recent retreat in oil prices underpinned the currency  near this week's three-month high on the dollar.