Controller for a synchronous rectifier switch

A method of operating a controller employable with a bridge rectifier having first and second synchronous rectifier switches, comprising:

• enabling a turn-on delay for said first synchronous rectifier switch with a plurality of series-coupled diodes of an amplifier;
• discharging a gate-to-source capacitance of said first synchronous rectifier switch with a discharge switch having a control terminal coupled to an output of said amplifier via a charge switch, and first and second switched terminals coupled to gate and source terminals, respectively, of said first synchronous rectifier switch to enable a turn off of said first synchronous rectifier switch;
• and
• reducing cross conduction between said first and second synchronous rectifier switches with a mutual lock circuit including a first lock switch and a second lock switch coupled to said gate terminal of said first synchronous rectifier switch and a gate terminal of said second synchronous rectifier switch, respectively, wherein a switched terminal of said first lock switch is cross-coupled to a control terminal of said second lock switch, a switched terminal of said second lock switch is cross-coupled to a control terminal of said first lock switch, and said first lock switch is parallel-coupled to said discharge switch.

A power converter, comprising:

• a bridge rectifier having first and second synchronous rectifier switches;
• and
• a controller, including:
• an amplifier configured to enable a turn-on delay with a plurality of series-coupled diodes for said first synchronous rectifier switch,
• a discharge switch having a control terminal coupled to an output of said amplifier via a charge switch, and first and second switched terminals coupled to gate and source terminals, respectively, of said first synchronous rectifier switch and configured to discharge a gate-to-source capacitance of said first synchronous rectifier switch to enable a turn off thereof, and
• a mutual lock circuit including a first lock switch and a second lock switch coupled to said gate terminal of said first synchronous rectifier switch and a gate terminal of said second synchronous rectifier switch, respectively, wherein a switched terminal of said first lock switch is cross-coupled to a control terminal of said second lock switch, a switched terminal of said second lock switch is cross-coupled to a control terminal of said first lock switch, and said first lock switch is parallel-coupled to said discharge switch.