Current driven synchronous rectifier with primary current sensing for LLC converter

A new synchronous rectifier driving circuit is proposed using primary current sensing and magnetizing current cancellation for LLC converter. The primary current in primary winding of transformer is used to generate the driving signal of SR. Because the magnetizing current of transformer is included in primary current, a current compensating scheme in current transformer is used to cancel the magnetizing current and generate a usable driving signal. With synchronous rectifier high efficiency can be achieve easily for LLC converter.