by xKOBAYASHIMARUx @ instructables.com:
Buck Converters are great! I use them all over the place in many of my nerdy, techy, geeky hobbiest projects. They also can commonly be referred to by other names, a DC-DC converter or a switching regulator. Essentially what it does is take some higher voltage in (higher than what you want for your project), chops it up, and pieces together a lower voltage. It might help to think of it as a transformer for DC circuits… only without the giant iron block… and without the long coils of wire… and with only 3 pins.
Buck Converter (DC-DC) – [Link]
The LTM8056 from Linear Technology is a 58 VIN, buck-boost μModule® (micromodule) regulator which requires just a few external passive components to complete the regulator design. Included in the package are the switching controller, power switches, inductor and support components. The basic external components needed are a single resistor to set the switching frequency, a resistor divider network to set the output voltage together with input and output capacitors. Other features such as input and output average current regulation may be implemented with just a few additional components. The LTM8056 operates with an input voltage ranging from 5 V to 58 V and can supply a regulated output voltage between 1.2 V and 48 V. The SYNC input and CLKOUT signal output provide clock synchronization options.
High Voltage Buck-Boost Regulator – [Link]
The LTC®3892/LTC3892-1 is a high performance dual step-down DC/DC switching regulator controller that drives all N-channel synchronous power MOSFET stages. Power loss and noise are minimized by operating the two controller output stages out-of-phase.
The gate drive voltage can be programmed from 5V to 10V to allow the use of logic or standard-level FETs and to maximize efficiency. Internal switches in the top gate drivers eliminate the need for external bootstrap diodes.
A wide 4.5V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. Output voltages up to 99% of VIN can be regulated. OPTILOOP ® compensation allows the transient response and loop stability to be optimized over a wide range of output capacitance and ESR values.
Buck controller needs just 29 µA in standby – [Link]
by Susan Nordyk @ edn.com:
The LTC3887 dual-output synchronous step-down DC/DC converter from Linear Technology differs from its predecessor, the LTC3880, by offering an enhanced feature set that includes a faster 70-ms power-up time, higher output voltage, and a speedy ADC mode that provides an 8-ms update rate for one parameter. Housed in a 40-pin, 6×6-mm QFN package, the LTC3887 occupies the same board footprint as the previous version and operates over a temperature range of -40 C to +125 C.
Gate drivers integrated within the LTC3887 drive all N-channel MOSFETs from input voltages of 4.5 V to 24 V. The converter can regulate two independent outputs or can be configured for a two-phase single output. Up to six phases can be interleaved and paralleled for accurate sharing among multiple ICs, minimizing input and output filtering requirements for high current and/or multiple-output applications. The LTC3887 provides output voltages from 0.5 V to 5.5 V, accurate to within +/-0.5%, with output currents of up to 30 A per phase over the full operating temperature range.
Buck converter starts up in just 70 ms – [Link]
by Susan Nordyk @ edn.com:
A family of pin-compatible synchronous step-down switching regulators with integrated power switches, the MIC28511/12/13 from Micrel, supplies up to 4 A of output current (MIC28513) and accepts a wide input supply range of 4.6 V to 70 V (MIC28512). The devices have an operating junction temperature range of -40°C to +125°C and come in very small 24-pin, 3×4-mm FCQFN packages.
The MIC28511/12/13 regulators are offered in both Hyper Speed Control and HyperLight Load architectures, which allow for high VIN (low VOUT) operation and fast transient response, while reducing the required output capacitance and providing good light-load efficiency. They furnish an adjustable output voltage as low as 0.8 V with guaranteed accuracy to within ±1%.
High-voltage buck regulators stay cool in tiny packages – [Link]
A synchronous buck-boost DC/DC converter that accepts 2.2 V to 18 V on each of its two inputs, the LTC3118 from Linear Technology enables high-efficiency operation from either input source to a programmable output voltage above, below, or equal to the inputs. Its dual-input capability is suitable for applications that employ batteries or supercaps as secondary or backup inputs, as well as those that use multiple sources, such as a wall adapter and Li-Ion cells.
The current-mode converter has a fixed 1.2-MHz switching frequency and furnishes up to 2 A of continuous output current from a wide range of power sources, including single or multiple-cell batteries, supercapacitor stacks, and wall adapters. Output voltage is programmable from 2 V to 18 V. Integrated low-loss PowerPath control is also user-programmable to prioritize and seamlessly transition between inputs, while maintaining output voltage regulation.
Buck-boost converter works with dual inputs – [Link]
The LTC®3899 is a high performance triple output (buck/ buck/boost) DC/DC switching regulator controller that drives all N-channel synchronous power MOSFET stages. The constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. The LTC3899 operates from a wide 4.5V to 60V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3899 can operate from an input supply as low as 2.2V after start-up.
LTC3899 – 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller – [Link]
PMP9194 uses the TPS54020 synchronous-buck SWIFT converter with integrated FETs to provide a 10A/1V solution in less than 22mmx12mm of total board space area. This reference design uses a small 1.1uH inductor, 2x100uF ceramic output capacitors, and small 0402 external components to save space. The device switches at 300kHz and acheives 87% peak efficiency from a 12V input to a 1V output. The TPS54020 is ideal for powering low-voltage, high-current DSPs and FPGAs, and can be synchronized 180 degrees out-of-phase with another TPS54020 to reduce input ripple.
4.5V to 17V Input, 10-A Synchronous Buck Converter Optimized for Small Size and Low Output Voltage – [Link]
by Susan Nordyk @ edn.com:
A synchronous PWM controller for negative-to-negative or negative-to-positive DC/DC conversion, the LT8709 from Linear Technology is easily configured for buck, boost, buck-boost, and inverting topologies to accommodate a wide range of power-supply designs. The device’s synchronous operation means that the output diode is replaced with a high-efficiency P-channel MOSFET, increasing efficiency and allowing for higher output currents of up to 20 A. It also eliminates the heat sink typically required in medium- to high-power applications.
The LT8709 operates over an input range of -4.5 V to -80 V and produces an output from -0.1 V to as high as 60 V or from -1.4 V to as low as -80 V. Its rail-to-rail output-current monitor and control enable the device to be configured as a current source. The controller has an EN/FBIN pin that accepts slowly varying input signals, as well as an adjustable undervoltage lockout function.
Buck/boost/inverting controller delivers up to 20 A – [Link]
The LT®8613 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 3μA of quiescent current. Top and bottom power switches are included with all necessary circuitry to minimize the need for external components. The built-in current sense amplifier with monitor and control pins allows accurate input or output current regulation and limiting. Low ripple Burst Mode operation enables high efficiency down to very low output currents while keeping the output ripple below 10mVP-P. A SYNC pin allows synchronization to an external clock.
LT8613 – 42V, 6A Synchronous Step-Down Regulator with Current Sense – [Link]