l6706 STMicroelectronics, l6706 Datasheet - Page 39

• Manufacturer Part Number: l6706
• Description: Vr11.1 Single Phase Controller With Integrated Driver
• Manufacturer: STMicroelectronics

L6706
17
Driver section
The integrated high-current driver allow using different types of power MOS (also multiple
MOS to reduce the equivalent R
The driver for the high-side MOSFETs use BOOT pin for supply and PHASE pin for return.
The driver for the low-side MOSFETs use VCCDR pin for supply and PGND pin for return. A
minimum voltage at VCCDR pin is required to start operations of the device.
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 LGATE pin is sensed. When it drops below 1V, 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 BOOT and VCCDR pin are separated from IC's power supply (VCC pin) as well as
signal ground (SGND pin) and power ground (PGND pin) in order to maximize the switching
noise immunity.
Doc ID 15698 Rev 1
ds(ON)
), maintaining fast switching transition.
Driver section
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