Buck Regulators

A buck converter, also called buck regulator or DC-DC step-down switching regulator, is a type of DC-DC converter that provides an output regulated voltage that is lower than its input voltage.

ST's monolithic step-down (buck) converter ICs offer input-voltage capability up to 61 V and deliver output currents up to 4 A with high switching frequency.

These buck regulators embed a full set of protection functions (overcurrent, overvoltage, and over-temperature) to increase the mean time between failures (MTBF) and reduce the number of external components required, thus lowering BOM costs.

Monolithic buck converter ICs (buck regulator) for any application requirement




Buck converters can be used for a large number of applications.

Product types: how to choose the right buck converter

Learn about ST broad selection of buck converters, designed to meet a wide range of requirements.

When a well-regulated rail is needed with minimum design effort, ST’s DC-DC portfolio jhas the right solution. Moreover, the need for only a few external components, internal compensation and synchronous rectification do not compromise performance and features.
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Feature-rich and flexible
Adjustable loop bandwidth, external clock synchronization, and adjustable soft start are some of the key features which allow designing a tailored solution for the final application.
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Low consumption
In systems where low power consumption is a must, like battery- or bus-powered applications, the buck converter needs to be very efficient in the conditions where the system is in idle state for most of the time.
Low-consumption buck converters feature ultra-low quiescent current and high efficiency at light load to meet these application requirements.
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Low noise
Buck converters offer a significant advantage in terms of efficiency compared to linear regulators.
However, they also introduce switching noise that could represent a big obstacle to comply with EMI standards and disturb noise-sensitive applications.
Low-noise buck converters help designers meet these challenges.
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The main target application of the isolated buck topology is to get a floating-voltage source. This is commonly required to provide supply to high-side gate drivers in high-power DC-DC converters, inverters, motor drivers, and other industrial applications.
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Wide input voltage
Wide input voltage (VIN) buck converters comply with unregulated input voltages or with bus voltages subjected to strong line transients typically occurring in industrial and telecom systems.
A short on-time ensures a large input-to-output conversion ratio while maintaining a high switching frequency.
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  • High-voltage technology together with high reliability, robustness, and compactness
  • High efficiency at any load and a high level of performance for consumer and computer products
Switching converters (DC-DC)
Quick reference guide
Technical Bulletin
L3751: Wide 6V to 75V Input Voltage Synchronous Buck Controller
STPD01: 1st buck converter for efficient USB-C PD power stages with cable drop compensation

38 V, 3 A synchronous buck converters for automotive applications

Nowadays, automotive systems require robustness, low consumption, high efficiency, and small size, especially for the vehicle electrification.

The A6983 is an AEC-Q100 qualified synchronous step-down converter suitable for battery-powered applications, car body applications, smart ambient lighting system supply, and car audio and low noise applications.

The A6983I is an AEC-Q100 qualified synchronous iso-buck converter specifically designed for isolated buck topology. It is particularly suitable for electric traction systems, OBC (on-board charger) for HEV/EV and automotive isolated IGBT/SiC MOSFET gate drive supply.

The STEVAL-A6983CV1, STEVAL-A6983NV1, and STEVAL-L6983IV1 evaluation boards are available to support developers in their designs.

L6983I: synchronous iso-buck converter for isolated applications

A floating-voltage source, which is the main target application of the isolated buck topology, is commonly requested to provide supply to high-side gate drivers in high-power DC-DC converters, inverters, motor drivers, and other industrial applications.​

The L6983I, specifically designed for isolated buck topology, provides a flexible, reliable, and easy-to-use solution for isolated IGBT/SiC/GaN MOSFET gate drive supplies, on-board chargers (OBC) for HEV/EV, and electric traction systems.

The STEVAL-L6983IV1 evaluation board is available to support developers in their designs.

About buck converters

How does a buck converter work?

A buck converter usually uses two switches and an inductor to make a voltage controlled current source that interacts with the parallel combination of output capacitor and load, to generate the desired output voltage (VOUT < VIN).

buck converter circuit diagram

Where and why is a buck converter used?

A buck converter is used to step down the voltage of a given input to achieve the required output voltage. Buck converters can be used in many applications, including smartphones, tablets, battery-powered equipment, industrial power systems and point-of-load supplies.

What are the advantages of a buck converter?

Buck converters offer a more efficient solution with fewer, smaller external components. They can step-down voltages using a minimal number of components. In the same time, they offer a lower operating duty cycle and higher efficiency across a wide range of input and output voltages.


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