A Bootstrap circuit for DC-DC converters with a wide input voltage range in HV-CMOS

Performance of MOSFET Driven via a Bootstrap Capacitor for Dynamic Load Continuity Enhancement

“…e main difficulty for low-and high-side switches at the same arm is the flow of the load current suddenly in the low-side freewheeling diode as a result of the negative voltage appearing at the source. Another problem caused by the negative voltage transient is the possibility to develop an overvoltage condition across the bootstrap capacitor [9,17].…”

“…e design of the BSC includes three main parts; the drive circuit, the MOSFET switch parameters, the BSD ratings, and the BSC specifications. e bootstrap capacitor is charged only when the low-side power switch is turned on and discharged when a high-side switch is turned on [17][18][19]. To maintain gate-source voltage within an acceptable minimum value, the capacitor voltage drop must be…”

“…e charge required by the internal level shifter according to the rated applied voltage is in the range (3-20 nC) for rated voltages from 500 to 1200 V. It is recommended to use the BSC of value about 2-3 times the minimum designed value to avoid overcharging. A decoupling capacitor may be used in addition to mitigate lowfrequency drains on the supply [17,19,20]. e applicable values of the capacitor for a duty cycle of 50% at different frequencies and different duties at a frequency of 50 Hz are shown in Figure 1 2.2.2. e Bootstrap Diode and Resistor.…”

“…e minimum charging time of the BSC must be verified against the time constant. e voltage drop across the BSC and its value affect directly the power dissipation in the BSR since a higher voltage drop will not allow a sufficient charging time [16,17,20]. Moreover, this work has been used with a BSD of 220V and a resistor of 1 Ω (typical values of BSR are 3 to 10 Ohms).…”

Buck converter IC for brushless DC motor drive using voltage‐mode PWM controller

“…This circuit does not have an area‐efficient topology and can be an instable source [14]. To solve those problems, a bootstrap circuit was proposed to charge the BSC without using an additional voltage supply [15]. Moreover, the bootstrap circuit employs a wide duty cycle range and a very wide input voltage range.…”