Edouard D. de Frésart

Current sense dynamics during turn-on of power MOSFET

During power MOSFET turn-on transient abnormal over-/undershoot currents in the sense FET are measured, impacting dramatically the mirror precision. The objective of the work is, based on sense FET explored dynamics, to elaborate guidelines to specify validation time for the sense measurement during turn-on, which is crucial for the system performance to achieve reliable control. We report analysis of current sense dynamics during turn-on of trench-gated MOSFET/65V. 3D device model is developed to study the impact of threshold voltage shift between power and sense device on CSR and sensing error, where wide spectrum of PWM mode switching slew rates are simulated.