The LT8640 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents. Its 3.4V to 42V input voltage range makes it ideal for automotive and industrial applications.
LT8640 – 42V, 5A Synchronous Step-Down Silent Switcher – [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]
by Steven Keeping:
Such is the popularity of DC-to-DC voltage converters (“switching regulators”)––due to their high efficiency across wide input- and output-voltage ranges––that chip makers have focused a lot of research dollars on squeezing the essential components of the devices into modules. These modules typically include pulse-width-modulation (PWM) controllers and switching elements in a single, compact package, easing the design work for the engineer.
However, until recently, it has proven difficult to include the energy-storage device (the inductor) inside the package. This has dictated that the engineer must specify, source, and design-in the inductor as a peripheral component, adding complexity and consuming board space. Now, a new generation of high-frequency switching regulators has enabled the use of smaller inductors enabling the devices to be housed inside the component vendor’s package.
The Advantages (and Drawbacks) of DC-to-DC Voltage Converters with Integrated Inductors – [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]
The LT®3744 is a fixed frequency synchronous step-down DC/DC controller designed to drive a LED load at up to 20A continuous or 40A pulsed. The peak current mode controller will maintain ±3% LED current regulation over a wide output voltage range, from VEE to VIN. By allowing VEE to float to negative voltages, several LEDs in series can be driven from a single Li-Ion battery with a simple, single step-down output stage. PWM dimming is achieved with the PWM pins. The regulated LED current is set with analog voltages at the CTRL pins. Regulated voltage and overvoltage protection are set with a voltage divider from the output to the FB pin. The switching frequency is programmable from 100kHz to 1MHz through an external resistor on the RT pin.
Additional features include an accurate external reference voltage, a control input for thermally derating regulation current, an accurate EN/UVLO pin, an open-drain output fault flag, OVLO, frequency synchronization, and thermal shutdown.
LT3744 – High Current Synchronous Step-Down LED Driver – [Link]
An application note from TI, TPS6122x low input voltage, 0.7V boost converter with 5.5μA quiescent current (PDF!):
The TPS6122x family devices provide a power-supply solution for products powered by either a single-cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Possible output currents depend on the input-to-output voltage ratio. The boost converter is based on a hysteretic controller topology using synchronous rectification to obtain maximum efficiency at minimal quiescent currents. The output voltage of the adjustable version can be programmed by an external resistor divider, or is set internally to a fixed output voltage. The converter can be switched off by a featured enable pin. While being switched off, battery drain is minimized. The device is offered in a 6-pin SC-70 package (DCK) measuring 2 mm x 2 mm to enable small circuit layout size.
TPS6122x low input voltage, 0.7V boost converter with 5.5μA quiescent current – [Link]
by Petre Petrov @ electronicdesign.com:
The bipolar NE555 timer IC is widely used in inductorless dc-dc converters, most frequently in doubling and inverting converters. However, another very popular IC, the LM386 audio amplifier, may be a better solution in this application. Note that the results also depend on the specific manufacturer of these multisourced ICs and on the quality of the related components. (We will use only Schottky diodes, to reduce the voltage losses to the minimum.)
Comparing the NE555 Timer and LM386 Amplifier as Inductorless DC-DC Converters – [Link]
by DAVID BURGOON @ edn.com:
There are several ways to produce a negative voltage from a positive voltage source, including using a transformer or two inductors and/or multiple switches. However, none are as easy as using the LTC3863, which is elegant in its simplicity, has superior efficiency at light loads and reduces parts count compared to alternative solutions.
The LTC3863 can produce a –0.4V to –150V negative output voltage from a positive input range of 3.5V to 60V. It uses a single-inductor topology with one active P-channel MOSFET switch and one diode. The high level of integration yields a simple, low parts-count solution.
AppNote: Inverting DC/DC controller converts a positive input to a negative output with a single inductor – [Link]