Shi Zhengrong, chairman and chief executive officer of Suntech Power Holdings Co Ltd, the world's largest solar panel maker by production capacity, is facing the dilemma of either having to quit the company he founded, or pay $575 million in convertible loans before they become due next March.

In 2008, Shi was named as the wealthiest man in China with a personal net worth of $2.9 billion, according to Forbes Magazine.

But the Wuxi-based company was hit hard by the shrinking demand for solar panels overseas, and turned to commercial banks for help to deal with the maturing debt.

The $575 million convertible debt due in March next year is Suntech's biggest financial pressure, but analysts say there is no way the company can pay the loans under its current capital constraints.

Commercial lenders have asked Suntech to either raise its borrowings, or use Shi's personal assets as collateral, said Feng Jie, head of a State-owned commercial bank in Jiangsu province, quoted on 163.com.

According to Suntech's 2011 annual report, Shi owns a 30.2 percent stake in the company, and his family trust holds another 29.4 percent.

As the deadline is approaching, more and more lenders are pushing Shi to reduce his holdings in Suntech.

Apart from the $575 million debt due in March, the solar panel maker is burdened with a further 200 million yuan ($32 million) in overdue loans, and there will be another 1.4 billion yuan in debts needing paid within the next six months, according to 163.com.