L6714 datasheet(27/70 Pages) STMICROELECTRONICS

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L6714

Device description

27/70

Device description

L6714 is four-phase PWM controller with embedded high current drivers that provides

complete control logic and protections for a high performance step-down DC-DC voltage

regulator optimized for advanced microprocessor power supply. Multi phase buck is the

simplest and most cost-effective topology employable to satisfy the increasing current

demand of newer microprocessors and modern high current VRM modules. It allows

distributing equally load and power between the phases using smaller, cheaper and most

common external power MOSFET and inductors. Moreover, thanks to the equal phase shift

between each phase, the input and output capacitor count results in being reduced. Phase

interleaving causes in fact input RMS current and output ripple voltage reduction and show

an effective output switching frequency increase: the 150kHz free-running frequency per

phase, externally adjustable through a resistor, results multiplied on the output by the

number of phases.

L6714 permits easy and flexible system design by allowing current reading across either

inductor or low side MOSFET in fully differential mode simply selecting the desired way

through apposite pin. In both cases, also a sense resistor in series to the related element

can be considered to improve reading precision. The current information read corrects the

PWM output in order to equalize the average current carried by each phase limiting the error

at ±3% over static and dynamic conditions unless considering the sensing element spread.

The controller includes multiple DACs, selectable through an apposite pin, allowing

compatibility with both Intel VR10,VR11 and AMD 6BIT processors specifications, also

performing D-VID transitions accordingly.

Low-Side-Less start-up allows soft start over pre-biased output avoiding dangerous current

return through the main inductors as well as negative spike at the load side.

L6714 provides programmable Over-Voltage protection to protect the load from dangerous

over stress. It can be externally set to a fixed voltage through an apposite resistor, or it can

be set internally, latching immediately by turning ON the lower driver and driving high the

FAULT pin. Furthermore, preliminary OVP protection also allows the device to protect load

from dangerous OVP when VCC is not above the UVLO threshold.

The Over-Current protection provided, with an OC threshold for each phase, causes the

device to enter in constant current mode until the latched UVP.

L6714 provides system Thermal Monitoring: through an apposite pin the device senses the

temperature of the hottest component in the application driving the Warning and the Alarm

signal as a consequence.

A compact 10x10mm body TQFP64 package with exposed thermal pad allows dissipating

the power to drive the external MOSFET through the system board.

L6714 bảng dữ liệu(PDF) 27 Page - STMicroelectronics