High Voltage Bootstrap Circuit

When the base of the transistor q1 is high and point b is low.

High voltage bootstrap circuit.

Here we have used bootstrapping technique to increase the input impedance of this amplifier circuit. The bootstrap circuit uses a coupling capacitor formed from the gate source capacitance of a transistor to drive a signal line to slightly greater than the supply voltage. Bootstrap circuit cb sourcing the figure below shows a typical waveform for the voltage across cb. The bootstrap circuit is useful in a high voltage gate driver and operates as follows.

When the vs goes below the ic supply voltage vdd or is pulled down to ground the low side switch is turned on and the high side switch is turned off the bootstrap capacitor cboot charges through the. To generate that high voltage a bootstrap circuit is used. The bootstrap circuit is useful in a high voltage gate driver and operates as follows. The voltage increases through the charging period when q2 is on.

10 some all pmos integrated circuits such as the intel 4004 use that 2 transistor bootstrap load circuit. Design and application guide of bootstrap circuit for high voltage gate drive ic by kevin angelo ma thursday september 29 2016 the purpose of this paper is to demonstrate a systematic approach to design high performance bootstrap gate drive circuits for high frequency high power and high efficiency switching applications using a power. Therefore the capacitor charges upto the value of voltage across r2. The bootstrap circuit is useful in a high voltage gate driver and operates as follows.

After connecting the circuit as per the circuit diagram the circuit looks similar to the darlington pair. Bootstrap circuit cb sourcing figure 1 2. The end of the charge cycle is closely followed by a high negative dv dt as the current needed for voa to charge the gate capaci. Figure 1 shows the charging path of a bootstrap circuit in a simplified half bridge configuration using ucc27710 ti s 620v half bridge driver with interlock.

Simple in structure a bootstrap circuit is a step up charge pump composed of a switch a capacitor and a diode where a voltage equal to the switch voltage vin plus the internal supply voltage is used as the gate drive for the high side nch mosfet.