This article explains the basic concepts of linear regulators and switching mode power supplies (SMPS). It is aimed at system engineers who may not be very familiar with power supply designs and selection. The basic operating principles of linear regulators and SMPS are explained and the advantages and disadvantages of each solution are discussed. The buck step-down converter is used as an example to further explain the design considerations of a switching regulator. by HENRY ZHANG
Smallest (2mm x 2.5mm), 8A, DC-DC Solution with Integrated MOSFETs in the Market
The MAX15108A high-efficiency, current-mode, synchronous step-down switching regulator with integrated power switches delivers up to 8A of output current. The regulator operates from 2.7V to 5.5V and provides an output voltage from 0.6V up to 95% of the input voltage, making the device ideal for distributed power systems, portable devices, and preregulation applications.
The IC utilizes a current-mode control architecture with a high gain transconductance error amplifier. The current-mode control architecture facilitates easy compensation design and ensures cycle-by-cycle current limit with fast response to line and load transients.
MAX15108A – High-Efficiency, 8A, Step-Down Switching Regulator - [Link]
The LTM4644 is a quad DC/DC step-down μModule (micromodule) regulator with 4A per output. Outputs can be paralleled in an array for up to 16A capability. Included in the package are the switching controllers, power FETs, inductors and support components – only bulk input and output capacitors are needed. Operating over an input voltage range of 4V to 14V or 2.375V to 14V with an external bias supply, the LTM4644 supports an output voltage range of 0.6V to 5.5V each set by a single external resistor. The LTM4644 is offered in 9mm ×15mm × 5.01mm BGA package.
LTM4644 – quad DC/DC step-down μModule regulator with 4A per output - [Link]
The LTC®3607 is a 15V dual 600mA monolithic synchronous step-down regulator which has only 55μA quiescent current. Intended for a variety of applications, including dual lithium-ion battery products, it operates from a wide 4.5V to 15V input voltage range. It features a constant 2.25MHz switching frequency, enabling the use of tiny, low cost capacitors and inductors 1mm or less in height. Each output voltage is adjustable from 0.6V to VIN. The internal synchronous power switches provide high efficiency without the need for external Schottky diodes.
LTC3607 – Dual 600mA 15V Monolithic Synchronous Step-Down DC/DC Regulator - [Link]
Linear Technology have announced the LTM4624 14V, 4A step-down µModule® (micromodule) regulator in a 6.25 x 6.25 x 5.01mm BGA package. Along with two (1206 package) ceramic capacitors and a (0603 or smaller package) resistor this complete regulator solution fits within 1cm² on a single-sided or 0.5cm² on a double-sided PCB. Like other µModule regulators in the range, the LTM4624 contains the DC/DC controller, power switches, inductor and compensation on-board. It is designed to operate from a 4V to 14V input supply, delivering a regulated output adjustable between 0.6V to 5.5V which according to Linear Technology make it ideal for applications in communications, storage, industrial, and medical systems. [via]
4A Step Down µModule in less than 1cm² - [Link]
The LT3690 is an adjustable frequency monolithic buck switching regulator that accepts input voltages up to 36V. A high efficiency 90mΩ switch is included on the device along with the boost diode and the necessary oscillator, control, and logic circuitry. The internal synchronous power switch of 30mΩ increases efficiency and eliminates the need for an external Schottky catch diode. Current mode topology is used for fast transient response and good loop stability. Shutdown reduces input supply current to less than 1μA. The low ripple Burst Mode maintains high efficiency at low output currents while keeping output ripple below 15mV in typical applications.
LT3690 – 36V, 4A, 1.5MHz Synchronous Step-Down Switching Regulator with 70μA Quiescent Current- [Link]
The MAX15062 high-efficiency, high-voltage, synchronous step-down DC-DC converter with integrated MOSFETs operates over a 4.5V to 60V input voltage range. The converter delivers output currents up to 300mA at output voltages of 3.3V (MAX15062A) and 5V (MAX15062B). The device operates over the -40°C to +125°C temperature range and is available in a compact 8-pin (2mm × 2mm) TDFN package. Simulation models are available.
MAX15062 – 60V, 300mA, Ultra-Small, High-Efficiency, Synchronous Step-Down DC-DC Converters - [Link]
The LT3763 is a synchronous buck LED driver controller that delivers over 300W of LED power. Its 6V to 60V input voltage range makes it ideal for a wide variety of applications, including automotive, industrial and architectural lighting. Similarly, its output voltage can be set from 0V to 55V, enabling it to drive a wide range of LEDs in a single string. The LT3763 offers both input and output current monitors and limiting, which accurately control both input and output current. The LT3763 also offers accurate output voltage regulation as well as input regulation, useful for high impedance sources such as solar panels. Its constant current and constant voltage regulation makes it ideal for applications ranging from driving high brightness LEDs to battery and supercap charging
LT3763 – 60V High Current Step-Down LED Driver Controller - [Link]
The MAX16962 is a high-efficiency, synchronous step-down converter that operates with a 2.7V to 5.5V input voltage range and provides a 0.8V to 3.6V output voltage range. The wide input/output voltage range and the ability to provide up to 4A to load current make this device ideal for on-board point-of-load and post-regulation applications. The MAX16962 achieves -3.7%/+2.6% output error over load, line, and temperature ranges.
MAX16962 – 4A, 2.2MHz, Synchronous Step-Down DC-DC Converter - [Link]
The TPS54160 device is a 60-V, 1.5-A, step down regulator with an integrated high-side MOSFET. Current mode control provides simple external compensation and flexible component selection. A low ripple pulse skip mode reduces the no load, regulated output supply current to 116 µA. Using the enable pin, shutdown supply current is reduced to 1.3 µA.
2.5MHz DC/DC converter protect against 65-V transients - [Link]