Contents
What are the losses in MOSFET?
Power loss in a rectifier MOSFET consists of conduction losses (PCON), body-diode conduc- tion losses (PBD), and gate losses (PGATE). There are no switching losses because of the body diode. The body diode conducts and the voltage across the FET is the diode voltage, which is zero.
What causes MOSFET losses?
Switch-MOSFET gate losses can be caused by the energy required to charge the MOSFET gate. That is, the QG(TOT) at the gate voltage of the circuit. These are both turn-on and turn-off gate losses. When turning the MOSFET on and off, the higher the switching frequency, the higher the gate-drive losses.
How are MOSFET conduction losses calculated?
Conduction loss is calculated between Section A and Section B of the waveform in Fig. 2. In Section A, the high-side MOSFET is ON and the low-side MOSFET is OFF. Therefore, conduction loss can be calculated from the output current, on- resistance and on-duty cycle.
How is the total power loss of MOSFET calculated?
The power efficiency of power MOSFET can be divided into two parts: conduction loss and switching loss. The total power loss can be calculated by combining the conduction loss and the switching loss as shown in the Eq. (1).
Why is crossover loss lower in lateral MOSFETs?
Crossover loss is a function of the switching speed of the MOSFET (gate resistance, gate source capacitance, and gate drain capacitance). For a given gate drive, lateral MOSFETs achieve faster transition which results in lower crossover loss as compared with a trench MOSFET. Lower crossover loss contributes to lower losses in a number of ways.
Where does the power come from in a switching MOSFET?
Many manufacturers of discrete switching MOSFETs employ a vertical trench process where the source of the MOSFET is located on the top of the silicon, the drain at the bottom, and current flows vertically through the device (incidentally, that is why the copper tab on a power package is typically at drain potential).
What causes switch-mosfetgatelosses in a circuit?
Switch-MOSFETgatelosses can be caused by the energy required to charge the MOSFET gate. That is, the QG(TOT) at the gate voltage of the circuit. These are both turn-on and turn-off gate losses.