High Side Gate Driver Bootstrap

When the low side fet is turned off and the high side is on the hs pin of the gate driver and the switch node are pulled to the high voltage bus hv.

High side gate driver bootstrap.

When the low side n fet turns off the low side of the bootstrap capacitor remains connected to the source of the high side n fet and the capacitor discharges some of its energy driving the gate of the high side n fet to a voltage sufficiently above v to turn the high side n fet fully on. Tronic lighting ballasts must rely not only on a properly selected high side low side gate driver ic but also on an external bootstrap circuit and its pcb layout. High impedance resistor for charging of bootstrap capacitor. What is driver bus voltage and which fet is high side low side.

Oscillations on one of the hs node based on switching sequencing. Based on infineon s soi technology having excellent ruggedness and noise immunity against negative transient voltages on vs pin. Gf085 high side gate driver fan7081 gf085 high side gate driver features qualified to aec q100 floating channel designed for bootstrap operation up fully operational to 600v tolerance to negative transient voltage on vs pin dv dt immune. The bootstrap capacitor discharges some of the stored voltage accumulated during the charging sequence to the high side fet through the ho and hs pins of the gate driver as shown in figure 2.

Using a single output gate driver for high side or low side drive 2 4 bootstrap bias supply with isolated high low side gate driver solution figure 5. Gate drive supply range from 10v to 20v under voltage lockout. Low side fet determines duty cycle. The bootstrap capacitor is charged during the on time of the low side switch and discharges quickly to fill up the gate capacitance but slowly discharges during the on time of the high side switch due to the high side driver s quiescent currents.

Isolated drivers using high side bootstrap circuit signal isolation the input signals of u1 are isolated in figure 5 with the isolated gate driver ucc53xx. High speed gate driver circuitry bootstrap gate drive technique the focus of this topic is the bootstrap gate drive circuit requirements of the power mosfet and igbt in various switching mode power conversion applications. Where input voltage levels prohibit the use of direct gate drive. Turn on both low side fets at the same time or place resistor from hs to ground.

The isodriver high side drive channel s require s a bootstrap circuit when the high side switch has a drain voltage greater than the isodriver s vdda supply.