L6759D datasheet(38/51 Pages) STMICROELECTRONICS

tên linh kiện	L6759D

Giải thích chi tiết về linh kiện	Fully configurable through PMBus

PDF	51 Pages

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38 / 51 page

Main oscillator

L6759D

38/51

Doc ID 023240 Rev 1

Figure 14.

ROSC vs. FSW per phase (ROSC to GND - left; ROSC to 3.3V - right)

10.1

LSLESS startup and pre-bias output

Any time the device resumes from an “OFF” code and at the first power-up, in order to avoid

any kind of negative undershoot on the load side, the L6759D performs a special sequence

in enabling the drivers: during the soft-start phase, the LS driver results as disabled

(LS=OFF - PWMx set to HiZ and ENDRV = 0) until the first PWM pulse. After the first PWM

pulse, PWMx outputs switch between logic “0” and logic “1” and ENDRV is set to logic “1”.

This particular sequence avoids a dangerous negative spike on the output voltage that can

happen if starting over a pre-biased output.

Low-side MOSFET turn-on is masked only from the control loop point of view: protections

are still allowed to turn on the low-side MOSFET in the case of overvoltage if needed.

Figure 15.

LSLESS startup: enabled (left) and disabled (right)

L6759D bảng dữ liệu(PDF) 38 Page - STMicroelectronics