This application details how a dual-channel LDO may be used to provide a dynamic voltage scaling output. This function is useful when powering microcontrollers that have a wide operating voltage range: it is advantageous to lower the operating voltage of the MCU in order to achieve lower power consumption (when possible).
The MSP430G2001, for example, has a supply voltage range that varies depending on the system frequency and programming modes. As an example, when the system frequency is 1MHz and flash memory programming is not required, the supply voltage range spans from 1.8V to 3.6V. However, if flash memory programming is required, the supply voltage range contracts to 2.2V to 3.6V.
Dynamic Voltage Scaling with a Dual LDO - [Link]
The LT®3042 is a high performance low dropout linear regulator featuring LTC’s ultralow noise and ultrahigh PSRR architecture for powering noise sensitive RF applications. Designed as a precision current reference followed by a high performance voltage buffer, the LT3042 can be easily paralleled to further reduce noise, increase output current and spread heat on the PCB.
The device supplies 200mA at a typical 350mV dropout voltage. Operating quiescent current is nominally 2mA and drops to <<1μA in shutdown. The LT3042’s wide output voltage range (0V to 15V) while maintaining unitygain operation provides virtually constant output noise, PSRR, bandwidth and load regulation, regardless of the programmed output voltage. Additionally, the regulator features programmable current limit, fast start-up capability and programmable power good to indicate output voltage regulation.
LT3042 – 20V, 200mA, Ultralow Noise, Ultrahigh PSRR RF Linear Regulator - [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]
Raj over embedded-lab.com has build a prototyping board that facilitates the building of simple circuits. It includes a regulated power supply for both 3.3V and 5V, four output LEDs, four input switches, a buzzer, a potentiometer and an onboard breadboard. Using this board you can fast prototype your next project.
Experimenter Prototyping Board for easy circuit build - [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]
The LTM4625 from Linear Technology is a switching mode μModule (micromodule) regulator in a tiny 6.25 mm × 6.25 mm × 5.01 mm BGA package. Like many of the newer regulator designs, the package includes the switching controller; power FETs, inductor and support components. Operating over an input voltage range of 4 V to 20 V (or 2.375 V to 20 V with an external bias supply) the LTM4625 supports an output voltage range of 0.6 V to 5.5 V, set by a single external resistor. Its high efficiency design delivers up to 5A continuous output current. Only bulk input and output capacitors are needed.
Complete 5A step-down Regulator - [Link]
by Susan Nordyk @ edn.com:
Leveraging Linear Technology’s Silent Switcher architecture and spread- spectrum frequency modulation, the LT8640 synchronous step-down switching regulator reduces EMI/EMC emissions by more than 25 dB—even with switching frequencies in excess of 2 MHz—enabling the part to easily pass automotive CISPR25, Class 5 peak limits. Synchronous rectification achieves efficiency as high as 95% with a switching frequency of 2 MHz, while the part’s 3.4-V to 42-V input range makes it useful for both automotive and industrial applications.
Step-down switching regulator minimizes EMI/EMC - [Link]
Linear Technology has squeezed a 3A voltage regulator into a package measuring just 6.25mm square and 1.8 mm high. The complete LTM4623 circuit only requires one input capacitor and one output capacitor, a resistor to set Vout and a small capacitor for Vout tracking and soft-start. At just 1.8mm height the regulator can be mounted on the PCB reverse side.
LTM4623 – Ultrathin 20VIN, 3A Step-Down DC/DC μModule Regulator - [Link]
by Haifeng Fan @ edn.com:
Isolated DC/DC converters are required in a broad range of applications including power metering, industrial programmable logic controllers (PLCs), insulated-gate bipolar transistor (IGBT) driver power supplies, industrial fieldbus, and industrial automation. These converters often are used to provide galvanic isolation, improve safety, and enhance noise immunity. Moreover, they can be used to generate multiple output voltage rails including dual-polarity rails.
Understanding isolated DC/DC converter voltage regulation - [Link]
by Steve Taranovich @ edn.com:
With many switching buck regulators on the market today that are capable of improving an automotive system design it is hard to choose the optimum one for your design. I patricularly like a new Linear Technology solution, the LT8609, a 2A, 42V input synchronous step-down switching regulator because it is unique in that it does not require an external flyback diode (sometimes called a snubber diode, freewheeling diode, suppressor diode, suppression diode, clamp diode or catch diode) which is a diode used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply voltage is suddenly reduced or removed. This makes for less external components.
Linear Technology 2A buck converter is 93% efficient at 2MHz - [Link]