Flexible system fault protection circuit design

When it is necessary to plug in a board into a system that is currently powered, it is critical to control the inrush current to prevent damage/system fault conditions. This application provides a simple circuit to achieve this function as well as an easy method for resetting the system and monitoring against temperature issues.

Step-down/inverting 3A, ±5V power supply with all-ceramic capacitor design

A MAX8538 dual synchronous buck controller supplies both +5V and -5V outputs at 3A. One controller operates as a synchronous rectified step-down (buck) converter while the second controller runs a transformer driven inverter. The circuit also features soft start and soft stop .

Power supplies that meet AMD K8 low-power mobile processor specifications

This application note describes a two-phase, synchronous, step-down converter that is fully compliant with the AMD® K8 Low-Power Mobile Specification. It includes details of the circuit operation, schematic, bill of materials, and a 1.2 volt, 27.3 Amp reference design with test data.

Charge battery via USB

Many devices with rechargeable batteries use USB power to recharge the batteries while they are connected. This application note describes the power available from USB and how it can be used to charge batteries, including circuits and some hints.

Provides three-channel, ±5% stable output high-efficiency PoE (Power over Ethernet) power supply

This note describes a triple-output, high efficiency, POE (Power over Ethernet) power supply with synchronous rectification. The supply has ±5% regulation an all outputs and meets all the IEEE802.3af requirements. The topology for the dc-dc converter is a continuous current flyback. The switching frequency for the primary PWM is 275 Khz.

IEEE 802.3af compliant single-port, powered device applications

Power-over-Ethernet (PoE) technology enables power-sourcing equipment (PSE, a switch/router or midspan system) to deliver up to 15W of power to IEEE® 802.3af-compliant powered devices like IP phones and wireless LAN access points. This application note describes how to design a single-port PSE system to meet the IEEE 802.3af signature, classification, and power-management requirements. The single-port PSE in this example is designed using the MAX5922A IC.

Designing a non-isolated flyback LED driver

Single NiMH battery simulates the circuit of a lithium battery

This circuit uses a NiMH cell to replace a lithium battery. Its output simulates the discharge characteristic of a lithium (Li+) battery.

UL certified IEEE 1394 standard single/dual port FireWire protection circuit

This application note describes Maxim's UL® Recognized, IEEE® 1394™, single- and dual-port FireWire® protective circuits. The single-port FireWire protective circuit is designed using the MAX5943A, while the dual-port FireWire protective circuit utilizes the MAX5944. To assist designers with implementing these circuits, this application note details the schematics, PCB layout, and bill of materials for each UL Recognized circuit.

Replace inefficient MR16 halogen lamps with LEDs

Replacing halogen lamps with LEDs in MR16 light fixtures can save substantial energy while reducing electricity and maintenance costs. This application note details the advantages of using LEDs in MR16 fixtures, and it presents an LED driver circuit that enables a 5W white LED with integrated heatsink to replace a 10W halogen bulb in MR16 lamps.

Using MAX15005 for power supply and driving of LED application systems

This reference design is a complete application design for an automotive LED application. It utilizes the MAX15005 current-mode controller to boost a standard lead-acid car battery to 21V for driving a string of automotive LEDs.

MAX5066 Reference Design for High-Performance Systems

The MAX5066 high performance dual buck regulator provides outstanding performance. The reference design in this application note depicts a detailed solution with complete schematic, bill of materials, and load-transient-response scope photos.

MAX5073 Dual Buck Converter Reference Design Operating at 2MHz Switching Frequency

The MAX5073 is a dual converter capable of operating as a buck or boost converter. As a dual buck converter, this device can deliver up to 2A and 1A of output current. The reference design focuses on the MAX5073 operating as a buck converter with a switching frequency of 2MHz, which allows the use of smaller passive components and keeps it out of the AM band for automotive applications.

Use DS3882 CCFL controller to drive the common circuit of two lights

This application note describes a backlight LCD application in which two adjacent CCFL lamps share a common, low-voltage side lamp connection. This design is found in automotive, industrial, and avionic applications. The article describes how a DS3882 CCFL controller can be used to drive the two CCFL lamps that share a common return.

PoE+ circuits provide 13W to 70W power to powered devices (PDs)

This application note presents a simple, cost-effective, pre-IEEE® 802.3at PoE+ Powered Decice (PD) solution that employs the MAX5941B. The preliminary requirements of PoE+ PDs are discussed, as is the advantage of extending the existing MAX5941B circuit to implement a PoE+ PD. Test results including inrush-current limit, efficiency, output ripple, and dynamic response are presented for a 3.3V, 30W PD.

Power consumption (PD) module reference design based on MAX5941B PWM controller

This application note provides a reference design for an IEEE® 802.3af-compliant, 12.95W adjustable-output powered-device module. Assembled on a 12cm² PCB, the module is based on the MAX5941B PWM controller and includes hot-swap power switching, a DC-DC converter, and a pair of ORing diode bridges for compatibility with an external 12V adapter. This article details the performance of the module and provides a schematic, PCB layout, and components list for the design.

Telecom hot-swap reference design effectively solves the problem of instantaneous input overvoltage and power outage

This 80W telecom hot-swap reference design is immune to 150V input-voltage transients and 16ms power dropouts. Additional features include -32V to -72V operation, two-diode OR-ing input, and an inrush current that is ≤ 1.5 times the full -load current. Included are a detailed schematic, representative PCB layout, bill of materials, waveforms detailing actual performance at startup, -150V input transient, and full-load holdup at power loss.

Design a car cold start boost circuit using the MAX15005 current mode controller

This reference design shows how to use a MAX15005 automotive power-supply controller as a boost circuit to maintain a constant voltage during an automotive cold-crank condition.

MR-16 LED driver and 5V auxiliary supply for powering pulsed LED coolers

This application note presents a reference design for a 4S1P MR-16 LED driver that provides 750mA to a string of four white LEDs (WLEDs). The circuit operates from a 24V source and is based around the MAX16820 hysteretic LED driver. Also included is a MAX5033 24V-to-5V, 150mA switching power supply to power a Nuventix® pulsating LED cooler.

Reference design to ensure dynamic output voltage of printhead power supply

This article describes some important design parameters for managing power in a printer. The reference design shows how to use a MAX15005 power-supply controller as a SEPIC circuit to obtain a high-variable output voltage for a print-head power supply. The circuit schematics , bill of materials (BOM), test measurements, and results are provided.