Considering the previously-identified specification, the designer may opt to use National’s LM5020 PWM controller. This is a design for application from LM5020. This is a single gate driver parallel FET circuit. This is the figure of the circuit;
Placing two FETs in parallel will increase switching losses as the gate charge will double and therefore switching transition times will double. With high RMS switch currents and the doubling of gate charge, it is essential to select FETs that have a low RDSON and a low gate charge. These types of FETs tend to be more costly than FETs that have similar RDSON with a higher gate charge. To address this transitional loss issue, the FET selected for this example is the SiR472DP FET from Vishay.
[Schematic circuit source: National Semiconductor Notes]
Placing two FETs in parallel will increase switching losses as the gate charge will double and therefore switching transition times will double. With high RMS switch currents and the doubling of gate charge, it is essential to select FETs that have a low RDSON and a low gate charge. These types of FETs tend to be more costly than FETs that have similar RDSON with a higher gate charge. To address this transitional loss issue, the FET selected for this example is the SiR472DP FET from Vishay.
[Schematic circuit source: National Semiconductor Notes]
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