Power Control

DC motors offer low cost and accurate drive performance for a range of applications. Depending on the application, a full-bridge, half-bridge, or just a step-down converter is used to drive the armature winding. The switches in these converters are pulse-width modulated (PWMed) to achieve the desired voltage. Analog Devices’ high-side or bridge-driver ICs like the MAX15024/MAX15025 can be used to drive the FETs in the full-bridge or half-bridge circuit. DC motors are also widely used in servo applications where speed and accuracy are important. To meet speed and accuracy requirements, microprocessor-based closed-loop control and information about rotor position are essential. ADI’s MAX9641 Hall effect sensor provides information about rotor position. Here is an example of an ultra low power, ultrasmall DC brush motor: MAX14870.

Analog Devices fan speed controllers provide all the functionality necessary for a power management system to regulate the speed of a fan via a 2-wire SMBus/I²C interface. Fan speeds are regulated per a system’s required temperature profile and results in lower fan power consumption, longer battery run time, and lower acoustical generated noise vs. systems that use simple on-off fan control.

Analog Devices’ family of offline power factor correction (PFC) controllers provide a power factor of up to 0.99 by actively modulating AC mains input current to comply with most harmonic current emission requirements. Many of these devices operate from an input voltage of 90 VAC to 265 VAC and produce a 400 VDC output, which typically powers an isolated downstream DC/DC converter. Some of these offline PFC controllers drive an external transformer, like the LT3798, which provides a combination of PFC, isolation, and regulated secondary voltage. Other offline PFC controllers, like the ADP1048W, provide signals that are converted into the digital domain to provide maximum flexibility, with key parameters reported and adjusted via a PMBus™ interface.

Analog Devices offers a unique family of PCMCIA switches and PCMCIA drivers for low loss switching of PCMCIA card power supplies. Their slowed rise time is critical in controlling the high in-rush current issues seen when charging a large capacitor. Additional features of this product family include low on-resistance VCC and VPP switching and SafeSlot current limiting to protect the card, socket, and power supply against accidental short-circuit conditions. A PCMCIA driver’s power-up/power-down sequencing can put demanding transient requirements on a system power supply. To make the transient manageable, most ADI PCMCIA switches, like the LTC1472, provide break-before-make switching and controlled rise and fall times.

Analog Devices’ family of current-mode pulse-width modulation (PWM) controllers operate at up to 500 kHz, have 1 A totem pole output, and no cross-conduction current.

Analog Devices’ synchronous secondary side controllers enable higher efficiency solutions, allowing higher power levels and smaller solutions size. Unlike prior solutions that used a signal transformer driven from the primary side to control the synchronous rectifier, our solutions sense the drain-to-source voltage of the MOSFET for activation. This technique not only eliminates a transformer, but allows the secondary side controller to work with ADI’s growing line of no-optocoupler products required for output voltage feedback boundary conduction mode (BCM)/critical conduction mode (CrCM) flyback converters, which makes it highly versatile for many types of applications.

Analog Devices’ transformer drivers offer small solution size, low EMI, and high performance for isolated power applications including isolated power supplies, high voltage battery stacks, and low EMI high power supplies. ADI offers both push-pull and H-bridge topologies optimized for a variety of power and voltage levels.

Analog Devices manufactures a broad line of high performance dc-to-dc controllers for CPU core power applications. These controllers support most CPU manufacturers’ product offerings and include Intel^® and AMD^® technology. In addition, the key benefits of using these controllers include a small solution footprint, reduced levels of capacitance, high conversion efficiencies, a fast transient response, and improved thermal management.