Li Ion Battery Charger | Electronic Project Circuits

Posts Tagged ‘li ion battery charger’

Li-Ion White LED Driver by LT1618

In addition to providing an accurate input current limit, the
LT1618 can also be used to provide a regulated output
current for current-source applications. {View Led driver Image} White LED drivers
are one such application for which the LT1618 is
ideally suited. With an input voltage range of 1.6V to 18V,
the LT1618 can provide LED drive from a variety of input
sources, including two or more alkaline cells, or one or
more Li-Ion cells. The circuit in Figure 7 is capable of
driving six white LEDs from a single Li-Ion cell. LED
brightness can be adjusted using a pulse width modulated
(PWM) signal, as shown, or by using a DC voltage to drive
the IADJ pin directly, without the R3/C3 lowpass filter. If
brightness control is not needed, simply tie the IADJ pin to
ground. Typical output voltage with the LEDs shown is
around 22V, and the R1, R2 output divider sets the
maximum output voltage to around 26V to protect the
LT1618 if the LEDs are disconnected. The LT1618â€™s
constant-current loop regulates 50mV across the 2.49W
sense resistor, setting the LED current to 20mA.

Be the first to comment - What do you think? Posted by admin - June 14, 2008 at 1:17 pm

Categories: Lighting Tags: current lightning, Led current limit, li ion battery charger, lithium battery

USB-Powered Lithium-Ion Battery Charger by LM3622

The battery-charger circuit is designed to operate as a high power USB function. To be compliant with USB Specifications (Rev. 1.1), a high-power function must not draw more than 500 mA from the bus during normal operation. The LM3622 uses the 0.25 current-limit resistor R1 to set a 400 mA maximum charging current. This leaves a 100 mA surplus that can be used to supply USB control circuitry and other functions in the device. There are additional current restraints on a high-power USB function that apply during system start-up or when a device is initially connected to an active bus. Until a device is properly configured by the USB system, the device may not draw more than 100 mA from the bus. In the above design, National Semiconductor s LM3525 USB power switch keeps the battery charger circuit isolated from the bus during start-up so that the charge current does not overload the bus. When the port is properly enumerated, a USB control signal enables the LM3525 switch, connecting USB power (VBUS) to the charger circuit. In addition to on-and-off switching, the LM3525 provides over-current and under-voltage protection to the design.

Read More Source:http://www.national.com/nationaledge/feb01/usb.html
Thank you.

Be the first to comment - What do you think? Posted by admin - April 6, 2008 at 3:34 pm

Categories: Battery charger Tags: li ion battery charger, lithium battery, USB Battery Charger

Li-ion Battery Charger for Mobile phone by TL431

This is a simple to build charger for single 3.7V lipo battery. The heart of the charger is TL431 shunt regulator that controls the incoming current. Charger comes with a convenient charging LED indicator. As charging current goes down so does the intensity of the LED.

Read More Source:http://www.belza.cz/charge/liich.htm
Thank you.