DC867A

DC867A demonstration circuit features the LTC4075X standalone linear charger that is capable of charging a single-cell Li-ion battery from both AC adapter and USB inputs. DC867A is designed to demonstrate the LTC4075X capability to automatically select the appropriate power source for charging. DC867A is set up so that when the USB source is used as the input, the charge current is set to 500mA and when the AC adapter is available, regardless of the USB input connection, the charge current increases to 800mA. The enable operation of the LTC4075X changes with different input sources. When the LTC4075X is charging from the AC adapter source, a “logic low” enables the charger and when the USB input is used for charging, “logic high” is needed to activate the LTC4075X. DC867A is design to start charging with AC adapter as default mode. For USB input charging, the JP1 jumper has to be set to the USB on position or the USB ENABLE pin (turret) has to be pulled above 1V.

• 4.3V to 6V input voltage range AC adapter and USB
• 4.2V ±1% o/p float voltage VBAT (constant voltage mode) (over full operating temperature (0-85°C))
• 800mA charge current AC adapter at R4 = 1.24K
• 476mA (500mA max, 0°C to 85°C) charge current USB input at R3 = 2.10K
• 50mA charge termination at R5 = 2.00K