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]
by Steve Taranovich @ edn.com:
Linear Technology Corporation just announced another in its series of power management ICs for automotive usage, the LT8640, a 5A, 42V input capable synchronous step-down switching regulator. A unique Silent Switcher™ architecture, combined with spread spectrum frequency modulation, reduces EMI/EMC emissions by more than 25dB even with switching frequencies in excess of 2MHz, enabling it to easily pass the automotive CISPR25, Class 5 peak limits. This feature varies the clock with a triangular frequency modulation of +20%.
Silent Switcher with high efficiency and low EMI/EMC – [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]
Linear Technology announces the LT3790, a synchronous buck-boost DC/DC controller that delivers up to 250 W of power with a single IC. Its 4.7 V to 60 V input voltage range makes it ideal for a wide variety of automotive and industrial applications. Its output voltage can be set from 0 V to 60 V, making it well suited as a voltage regulator or battery/supercapacitor charger. The LT3790’s internal 4-switch buck-boost controller operates from input voltages above, below or equal to the output voltage, making it ideal for applications such as automotive, where the input voltage can vary dramatically during stop/start, cold crank and load dump scenarios. Transitions between buck, pass-through and boost operating modes are seamless, offering a well regulated output in spite of wide variations of supply voltage. The LT3790’s unique design utilizes three control loops to monitor input current, output current and output voltage to deliver optimal performance and reliability.
60V, Synchronous Buck-Boost Controller – [Link]
The LMR16006 is a PWM DC/DC buck (step-down) regulator. With a wide input range of 4 V to 60 V, it is suitable for a wide range of application from industrial to automotive for power conditioning from an unregulated source. The regulator’s standby current is 28 µA in ECO mode, which is suitable for battery operating systems. An ultra low 1 µA shutdown current can further prolong battery life. Operating frequency is fixed at 0.7 MHz (X version) and 2.1 MHz (Y version) allowing the use of small external components while still being able to have low output ripple voltage. Soft-start and compensation circuits are implemented internally, which allows the device to be used with minimized external components. The LMR16006 is optimized for up to 600 mA load currents.
LMR16006 SIMPLE SWITCHER 60V Buck Regulators with High Efficiency ECO Mode – [Link]
App note(PDF) from NXP on DC-DC medium power small-signal MOSFETs.
This application note explores different methods of DC-to-DC conversion. It includes some examples of DC-to-DC down-converters using small-signal MOSFETs.
App note: Medium power small-signal MOSFETs in DC-to-DC conversion – [Link]
by SparkFun Electronics @ youtube.com:
In today’s episode of “According to Pete,” SparkFun Director of Engineering Pete Dokter is taking a look at homelighting solutions and the SparkFun FemtoBuck LED Driver
SparkFun According to Pete #40: LED Home Lighting and the FemtoBuck Driver – [Link]
Sometimes you learn about an interesting IC and you build an entire circuit around it for no other good reason… This project is one of those!
The TPS2378 is an IEEE802.3at (Power over Ethernet) Powered Device controller, featuring internal pass MOSFET for loads up to 25.5W, Type 1 (a.k.a. 802.3af) compatibility and auxiliary power source support.
The IC is normally used together with a DC-DC step down regulator to power a network device (the PD) from a PoE compliant switch or injector (the PSE). A proper 802.3at device requires an isolated power supply with some safety characteristics that makes it not trivial to implement, and there are many DC-DC ICs with integrated PoE controller to make it easier, but as I wasn’t really interested in that part I just went for an easier project with just the PoE controller and some ballast… And what better ballast than some high power white LEDs!
Power over Ethernet Flashlight – [Link]
Linear Technology Corporation announces the LTC3371, a highly integrated general-purpose power management solution for systems requiring multiple low voltage power supplies. The device features four synchronous buck converters, each powered from independent 2.25 V to 5.5 V inputs, and each configurable to share up to four of eight available 1 A power stages. With eight unique output current configurations, the LTC3371 provides substantial flexibility and ease of reuse across many different applications. The device is ideal for a wide variety of multichannel industrial, automotive, communications and distributed power systems.
Configurable Buck DC/DCs Deliver a Total of 8A from 2 to 4 Independent Outputs for Power System Flexibility – [Link]