L6713A datasheet(51/64 Pages) STMICROELECTRONICS

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L6713A

Driver section

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Driver section

The integrated high-current drivers allow using different types of power MOS (also multiple

MOS to reduce the equivalent RDS(on)), maintaining fast switching transition.

The drivers for the high-side MOSFETs use BOOTx pins for supply and PHASEx pins for

return. The drivers for the low-side MOSFETs use VCCDRx pin for supply and PGNDx pin

for return. A minimum voltage at VCCDRx pin is required to start operations of the device.

VCCDRx pins must be connected together.

The controller embodies a sophisticated anti-shoot-through system to minimize low side

body diode conduction time maintaining good efficiency saving the use of Schottky diodes:

when the high-side MOSFET turns OFF, the voltage on its source begins to fall; when the

voltage reaches 2 V, the low-side MOSFET gate drive is suddenly applied. When the low-

side MOSFET turns OFF, the voltage at LGATEx pin is sensed. When it drops below 1 V, the

high-side MOSFET gate drive is suddenly applied.

If the current flowing in the inductor is negative, the source of high-side MOSFET will never

drop. To allow the turning on of the low-side MOSFET even in this case, a watchdog

controller is enabled: if the source of the high-side MOSFET doesn't drop, the low side

MOSFET is switched on so allowing the negative current of the inductor to recirculate. This

mechanism allows the system to regulate even if the current is negative.

The BOOTx and VCCDRx pins are separated from IC's power supply (VCC pin) as well as

signal ground (SGND pin) and power ground (PGNDx pin) in order to maximize the

switching noise immunity. The separated supply for the different drivers gives high flexibility

in MOSFET choice, allowing the use of logic-level MOSFET. Several combination of supply

can be chosen to optimize performance and efficiency of the application.

Power conversion input is also flexible; 5 V, 12 V bus or any bus that allows the conversion

(See maximum duty cycle limitations) can be chosen freely.

L6713A bảng dữ liệu(PDF) 51 Page - STMicroelectronics