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Renesas Singapore - Knowledgebase

Can you explain about G-S switching operations?

Latest Updated:09/02/2013


Is it possible to turn drain (D) to source (S) on and off by switching the gate (G) to drain (D) voltage (0 to 10 V)? If it is possible, is the D-S on-resistance the same whether 10 V is applied to G-S or G-D, or does it differ?


A MOSFET carries out switching operation according to the G-S voltage. It depends on your circuit configuration, but depending on how you are using it there is the possibility that G-S voltage could be undefined and thus correct operation would not occur. Possible issues are as follows.

  • Oscillation could occur when the gate to source voltage is close to the threshold voltage.
  • When turning on: If sufficient gate to source voltage is not obtained, drain current will flow while the drain to source voltage has not dropped. This is outside the area of safe operation.
  • When turning off: Gate to source voltage could be caused by noise on the power supply line or by voltage fluctuation. This would cause malfunction and unintended operation of the load.
Suitable Products
Power MOSFETs for General Switching