By Steve Bush 18th October 2022
An input range of 6V to 75V is the eye-catching spec of STMicroelectronics’ L3751 synchronous buck controller, and many of its inputs can tolerate 100V.
Its has a constant-frequency voltage-mode architecture, with its output voltage compared to an 800mV internal reference through a feedback pin. Input voltage feed-forward is implemented to improve line transient response.
100kHz – 1MHz switching and its 40ns minimum on-duration allows it to support extremely low duty-cycles and deliver 800mV to 60V.
The IC needs a pair of external n-channel mosfets to work, and includes a 7.5V supply (assuming enough input voltage) for the in-built gate drivers.
Diode emulation implements pulse skipping to maximise efficiency at light-load, although PWM mode can be forced to hold the switching frequency constant and minimise output voltage ripple.
Soft-start circuitry limits in-rush current during start-up, and a power good (Vout >87% of target) open-collector output is available for monitoring or to implement power-up voltage sequencing.
Protections include output over-current, input under-voltage lock-out and thermal shutdown. Hiccough circuitry handles over-load and short-circuit conditions.
Input over-voltage-lock-out is implemented through the enable pin, which has precision thresholds and controls three modes: shut-down, under-voltage idle and operating. “The central tap of a resistor divider connected to the pin from Vin designs the enable and under-voltage lockout thresholds”, said ST.
Packaging is 3.5Â x 4.5mm 20pad QFN with wettable flanks.
ST foresees it being used in applications from industrial equipment to battery-powered light electric vehicles, as well as in telecom and networking equipment that have 24V or 48V buses.
STEVAL-L3751V12 is the associated 100W evaluation board (right) which is set to convert 6 – 75V into 5V (default 15A), although 12V out can be set with a jumper. Switching is at 230kHz, synch-able from 185 to 345kHz
The L3751 product page can be found here.
Tagged with: dc-dc DC-DC converter STMicroelectronics
Your email address will not be published. Required fields are marked *
Download the Elektra Awards 2022 media pack and book your sponsorship package to be part of the most prestigious awards event celebrating its 20th anniversary this year!
Have your say in choosing the most promising UK university research project reported in the last year, from Bristol or ICL to Surrey or Southampton, and robotic fingers to flexible and stretchy supercapacitors...
Get our news, blogs and comments straight to your inbox! Sign up for the Electronics Weekly newsletters: Mannerisms, Gadget Master and the Daily and Weekly roundups.
Read our special supplement celebrating 60 years of Electronics Weekly and looking ahead to the future of the industry.
Read the Electronics Weekly @ 60 supplement »
Read the first ever Electronics Weekly online: 7th September 1960. We've scanned the very first edition so you can enjoy it.
Read the very first edition »
Electronics Weekly teams up with RS Grass Roots to highlight the brightest young electronic engineers in the UK today.
Read our special supplement celebrating 60 years of Electronics Weekly and looking ahead to the future of the industry.
Read the Electronics Weekly @ 60 supplement »
Read the first ever Electronics Weekly online: 7th September 1960. We've scanned the very first edition so you can enjoy it.
Read the very first edition »
Tune into this Xilinx interview: Responding to platform-based embedded design
Tune into this podcast to hear from Chetan Khona (Director Industrial, Vision, Healthcare & Sciences at Xilinx) about how Xilinx and the semiconductor industry is responding to customer demands.
By using this website you are consenting to the use of cookies. Electronics Weekly is owned by Metropolis International Group Limited, a member of the Metropolis Group; you can view our privacy and cookies policy here.