by Richard Quinnell @ edn.com:
Aiming to simplify design and increase power density in industrial systems, Intersil has developed the ISL8817 synchronous buck controller. The device accepts DC input voltages from 4.5V to 60 V and produces a selectable output voltage between 0.6V and 54V at up to 20A output current. Able to operate over a wide switching frequency (100 kHz to 2 MHz) with a low duty cycle (40 nsec minimum on time), the controller is able to step down from a 48V source to a 1V output in a single stage. This allows industrial applications using a 48V power distribution bus to provide the many voltages that modern CPUs and FPGAs require without the need for an intermediate low-voltage stage. This both increases power density in such systems as well as reducing conversion losses.
Buck controller allows 48V to 1V direct step-down – [Link]
The LT8616 is a high efficiency dual synchronous monolithic step-down switching regulator with an input voltage range of 3.4V to 42V. Its dual channel design delivers independent 2.5A and 1.5A continuous current to outputs as low as 0.8V. A dual channel synchronous rectification topology delivers up to 95% efficiency while Burst Mode operation keeps quiescent current under 6.5μA (both channels enabled) in no-load standby conditions, making it ideal for always-on systems. Switching frequency can be programmed from 200kHz to 3MHz and is synchronizable throughout this range. The LT8616’s 35ns minimum on-time enables 16V to 1.8V step-down conversions, while switching at 2MHz helps designers avoid critical noise-sensitive frequency bands, such as AM radio while having a very compact solution footprint.
LT8616 – Dual 42V Synchronous Monolithic Step-Down Regulator with 6.5μA Quiescent Current – [Link]
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 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]
By Chris Glaser @ ti.com:
Especially for switch-mode power supplies (SMPSs), the printed circuit board (PCB) layout is a critical but often under appreciated step in achieving proper performance and reliability. Errors in the PCB layout cause a variety of misbehaviors including poor output voltage regulation, switching jitter, and even device failure. Issues like these should be avoided at all costs, since fixing them usually requires a PCB design modification. However, these pitfalls are easily circumvented if time and thought are spent during the PCB layout process before the first PCBs are ever ordered. This article presents five simple steps to ensure that your next step-down converter’s PCB layout is robust and ready for prototyping.
Five steps to a great PCB layout for a step-down converter – [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]
Intersil have introduced a single chip just 9 x 6.5 mm which contains just about all the control features (including the output stages) needed to build a dual 0.8 to 5 V power supply with 3 A per channel output capability. The ISL8203M can also supply 6 A in current sharing operation.
The ISL8203M is an integrated step-down power module optimized for generating low output voltages down to 0.8V. The input supply voltage range spans from 2.85 V to 6 V. The two channels are clocked 180° out-of-phase to help reduce input RMS current and EMI. While in current sharing mode this interleaving of the two channels is beneficial for reducing input and output voltage ripple.
Dual 3A PSU on a Chip – [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]
Susan Nordyk @ edn.com:
Encapsulated in a tiny 9.0×6.5×1.83-mm QFN package, the ISL8203M step-down DC/DC power module from Intersil furnishes an adjustable output voltage between 0.8 V to 5 V to allow designers to use one device to build a single 6-A or dual 3-A output power supply. The ISL8203M simplifies power-supply design for FPGAs, ASICs, microprocessors, DSPs, and other point-of-load conversions in communications, test and measurement, and industrial systems.
Intersil shrinks step-down DC/DC power module – [Link]