Functional description

PWD13F60

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DocID030865 Rev 2

6.2

Bootstrap structure

Bootstrap circuitry is typically used to supply the high-voltage section. This function is

normally accomplished by a high-voltage fast recovery diode (see Figure 13 a).

In the PWD13F60 a patented integrated structure replaces the external diode. It is realized

by the series of the low-voltage diode and a high-voltage DMOS, driven synchronously with

the low side driver (LVG), as shown in Figure 13 b. An internal bootstrap provides the

DMOS driving voltage. The integrated diode structure is actively turned on and guarantees

the best performance when the low side driver is on.

In those applications whose control strategy requires recharging the bootstrap capacitor

also when the low side driver is off, the use of an external bootstrap diode in parallel to the

integrated structure is possible.

Figure 13. Bootstrap structure

6.3

The VCCx supply pin supplies the current to the low side section of the gate driver as well

as to the integrated bootstrap diode used to charge the bootstrap capacitor. During outputs

commutations the average current used to provide gate charge to the high side and low side

MOSFETs flow through these pins.

The two pins VCC1 and VCC2 separately supply power to the two drivers even if usually are

connected together at the power supply in the final application.

lockout (UVLO) circuitry that turns the high side and low side MOSFETs off when the supply

accordingly to the LIN and HIN status, as soon as the supply voltage goes above the

occurs on a single rail, only the related half bridge MOSFETs are turned off.