L6730D datasheet(19/50 Pages) STMICROELECTRONICS

Numer części	L6730D

Szczegółowy opis	Adjustable step-down controller with synchronous rectification

PDF	50 Pages

Scroll/Zoom	100%

Producent	STMICROELECTRONICS [STMicroelectronics]

Strona internetowa	http://www.st.com

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19 / 50 page

L6730C - L6730D

Device description

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5.7

Driver section

The high-side and low-side drivers allow using different types of power MOSFETs (also multiple

MOSFETs to reduce the RDS(on)), maintaining fast switching transitions. The low-side driver is

supplied by VCCDR while the high-side driver is supplied by the BOOT pin. A predictive dead

time control avoids MOSFETs cross-conduction maintaining very short dead time duration (see

Figure 10.).

The control monitors the phase node in order to sense the low-side body diode recirculation. If

the phase node voltage is less than a certain threshold (-350mV typ.) during the dead time, it

will be reduced in the next PWM cycle. The predictive dead time control doesn’t work when the

high-side body diode is conducting because the phase node doesn’t go negative. This situation

happens when the converter is sinking current for example and, in this case, an adaptive dead

time control operates.

Figure 10. Dead times

L6730D Arkusz danych(PDF) 19 Page - STMicroelectronics