Design of the Trickle Charge Pump in Gate Driver Applications

Gate driver technologies are becoming more and more widespread in motor driving applications due to their low cost and high power-efficiency. These drivers are commonly assisted by an auxiliary bootstrap circuitry which is a simple solution toward driving the power switches in an efficient way by exploiting the bootstrap capacitor. This capacitor is responsible to provide enough charge for the high-side switch and powering up the high-side circuitry at the same time. Micro fabrication of this capacitor into smaller size in the range of few nano Farads will require a solution to compensate the charge. Furthermore, by moving toward new applications with higher duty cycles, the bootstrap capacitor may face critical timing challenges to acquire adequate amount of charge. In this thesis, characterization and measurements on different parameters of the gate driver with special focus on the bootstrap circuit will be performed. In the following sections, the design of the so called “Trickle Charge Pump” with the purpose of providing enough charge for the bootstrap capacitor will be proposed. This structure is fulfilled with the components in compliant with the current technology used at Infineon company. The simulation and feasibility of this structure will be explored through a system level simulator called “SIMetrix”. At the end of this work, results and future improvements toward the full use of the trickle charge pump will be discussed.