ST Manuals

This application note describes, step-by-step, all the principles and calculations used for a modified buck converter intended for high brightness LED applications. The converter is designed as a constant current source to achieve the best lighting performance from the LEDs.

AN2831 application note introduces how to use STw4102 chip to implement Li-Ion battery charging and monitoring

The PM6681A is a dual step-down controller with adjustable output voltages that can be used in notebook power systems.

This application note focuses on the design of a flash LED driver using the STCF05 device, which is a boost current mode converter with an I²C interface and internal current source. The schematic, functional description, recommendations for PCB layout, and external component selection are also discussed in this application note. The STCF05 device is designed to drive two LEDs in series with a total forward voltage range from 5.3 V to 10.2 V.

This document introduces the LED current source based on L5973AD and the basic principles and applications of LEDs. The brightness of LEDs is proportional to the forward current flowing through them. LEDs can be divided into low current LEDs and high current LEDs based on the typical forward current of the final application. The voltage drop across LEDs varies widely, so current mode driving is more convenient. The current source regulates the LED current and the output voltage is determined by the forward voltage of each LED.

This application note describes a NiMH battery charger demonstration board used with a USB microcontroller.

The PM6675S device is a high-efficiency step-down controller with an embedded 2 A LDO linear regulator. The constant on-time (COT) architecture assures fast transient response supporting both electrolytic and ceramic output capacitors. An embedded integrator control loop compensates the DC voltage error due to the output ripple. Selectable low-consumption mode allows the highest efficiency over a wide range of load conditions. The low-noise mode sets the minimum switching frequency to 33 kHz for audio-sensitive applications. The LDO linear regulator can sink and source up to 2 Apk. Two fixed current limits (±1 A and ±2 A) can be chosen. An active soft-end is independently performed on both the switching and the linear regulators outputs when disabled.

The PM6675AS is a high-efficiency step-down controller with an embedded 2A LDO regulator. It features fast transient response, selectable low-consumption mode, and low-noise mode.

Introduces the features and application of VIPER17HN for non-isolated LED constant current driver

The LED7707 LED driver is a high-efficiency monolithic boost converter and six controlled current generators (rows), specifically designed to supply LED arrays used in the backlighting of LCD panels. The device can manage an output voltage up to 36 V (i.e. ten white-LEDs per row). The generators can be externally programmed to sink up to 85 mA and can be dimmed via a PWM signal (1% of minimum dimming duty-cycle at 1 kHz can be managed). The device allows detection and management of open and shorted LED faults, and permits unused rows to be left floating. Basic protections (output overvoltage, internal MOSFET overcurrent and thermal shutdown) are provided.

The LED7706 is a high-efficiency LED driver chip from STMicroelectronics. It can provide up to 36V of power for LCD panel backlights and can be dimmed using a PWM signal.

The PM6670S is a complete DDR2/3 power supply regulator designed for portable applications to meet JEDEC specifications. It integrates a constant on-time (COT) buck controller, a 2 Apk sink/source low dropout regulator (LDO), and a 15 mA low noise buffered reference. The COT architecture ensures a fast transient response supporting both polymeric and ceramic output capacitors. An embedded integrator control loop compensates the DC voltage error caused by the output ripple. The 2 Apk sink/source linear regulator provides the memory termination voltage with a fast load transient response. The device is fully compliant with system sleep states S3, S4, and S5, setting the LDO output to high-impedance in the suspend-to-RAM state, and performing the tracking discharge of all outputs in the suspend-to-disk state.

PM6670AS is a complete DDR2/3 power supply regulator for portable applications designed to meet JEDEC specifications