Bootstrap capacitor high side driver

For this reason, the conventional voltage converter employs a bootstrap capacitor C Bootstrap connected between the high-side power input Boot of the high-side driver and the source of the Cited by: bootstrap capacitor, C BOOT, can become overcharged and the high-side gate-driver circuit has damage by over-voltage stress because it exceeds an absolute maximum voltage (VBSMAX) specified in datasheet. Design to a bootstrap cir-cuit, that does not exceed the absolute maximum rating of high-side gate driver. Effect of Parasitic Inductances. bootstrap capacitor should be sized to have enough energy to drive the gate of the high-side MOSFET without being depleted by more than 10%. This bootstrap cap should be at least 10 times greater than the gate capacitance of the high-side FET. The reason for that is to allow for capacitance shift from DC bias.

One of the most widely used methods to supply power to the high-side drive circuitry of a gate driver IC is the bootstrap power supply. The bootstrap power supply consists of a bootstrap diode and a bootstrap capacitor; this circuit is illustrated in Figure 1. Figure 1: bootstrap power supply. Most control schemes that use a bootstrap capacitor force the high side driver (N-MOSFET) off for a minimum time to allow for the capacitor to refill. This means that the duty cycle will always need to be less than % to accommodate for the parasitic discharge unless the leakage is accommodated for in another manner. I am trying to calculate the minimum capacitor size in a bootstrap for an IRS gate driver. I have included the equation by IR's application notes. What I am not getting are the values of Vls and Vmin. If I am inverting V that means Vls would V? because that would be the drop across the lowside FET as its S is connected to ground.

The MPx families of three-phase pre-drivers have a number of protection Bootstrap capacitors need to be large enough so that the high side MOSFET is. A bootstrap circuit is used for the gate drive of the high-side (upper-leg) devices of a bridge circuit. When the low-side (lower-leg) device turns on. components, as bootstrap circuit and on/off gate resistors; amount of charge that is needed when the high voltage side of the driver is floating.