High Voltage Bootstrap Circuit
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.
High voltage bootstrap circuit. Bootstrap circuit cb sourcing figure 1 2. 10 some all pmos integrated circuits such as the intel 4004 use that 2 transistor bootstrap load circuit. After connecting the circuit as per the circuit diagram the circuit looks similar to the darlington pair. The bootstrap circuit is useful in a high voltage gate driver and operates as follows.
When the base of the transistor q1 is high and point b is low. The bootstrap circuit is useful in a high voltage gate driver and operates as follows. The bootstrap circuit is useful in a high voltage gate driver and operates as follows. 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.
Bootstrap circuit cb sourcing the figure below shows a typical waveform for the voltage across cb. Here we have used bootstrapping technique to increase the input impedance of this amplifier circuit. 2 basic operation of bootstrap circuit a bootstrap circuit is used in half bridge configurations to supply bias to the high side fet. 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.
To generate that high voltage a bootstrap circuit is used. 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. The voltage increases through the charging period when q2 is on. 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.
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.