circuit coll

Using the ISL97672A can be designed a power LED driver circuit that controls six channels of LED current for LCD backlight applications. The ISL97672A power LED driver is capable of driving LEDs from 4.5V to 26.5V, with a maximum output of 45V.
The ISL97672A power LED driver employs an adaptive boost switching architecture that allows Direct PWM dimming with linearity as low as 0.007% at 200Hz or 0.8% at 20kHz. Dimming can be as high as 30kHz.
This LED driver can compensate for non-uniformity of forward voltage drops in the LED strings. Its headroom control circuit monitors the highest LED forward voltage string for output regulation to minimize voltage headroom and power loss in a typical multi-string operation.
The IC features extensive protection functions that flag whenever a fault occurs. The protections include string-open and short-circuit detections, OVP, OTP, and an optional output short-circuit protection with a fault disconnect switch

LED drivers for direct, multiplexed videowalls, information displays circuits

A very simple solar charger circuit project can be designed using few external electronic parts . This simple solar charger circuit is capable of handling charge currents of up to 1A. Alternate component values are given in the figure for lower current applications.

Circuit diagram:

 Solar charger circuit project using transistors circuit diagram

The only adjustment is the voltage trip point when the current is shunted through the transistor and load resistor. This should be set with a fully charged battery. As the transistor and R3 have the entire panel’s output across them when the battery is fully charged, all of the current from the panel will be going through R3 and the Darlington transistor TIP112, so these must be well heat sunk. Adjust R1 for the trip point, usually 14.4 V – 15 V for a 12 V SLA or a 12 V Ni-Cd battery.

source :www.electroniq.net