The power MOSFET breakdown voltage is rated for VLED+VD (output voltage+diode drop). When the topology changes to a SEPIC, the power MOSFET switch must have a breakdown voltage of VIN+VOUT+VD.
For Buck-Boost Configuration:
VDS= (VLED+ VINMAX+ VD) x 1.2
VDS is the drain-to-source voltage in volts and VD is the forward drop of rectifier diode D1. The factor of 1.2 provides a 20% safety margin.
For Buck-Boost Configuration:
VDS= (VLED+ VINMAX+ VD) x 1.2
VDS is the drain-to-source voltage in volts and VD is the forward drop of rectifier diode D1. The factor of 1.2 provides a 20% safety margin.
For Boost Configuration:
VDS= (VLED+ VD) x 1.2
VDS is the drain-to-source voltage in volts and VD is the forward drop of rectifier diode D1. The factor of 1.2 provides a 20% safety margin.
VDS= (VLED+ VD) x 1.2
VDS is the drain-to-source voltage in volts and VD is the forward drop of rectifier diode D1. The factor of 1.2 provides a 20% safety margin.