The BQ25040EVM is an evaluation module (EVM) for BQ25040. The bq25040 is an integrated Li-ion linear battery charger targeted at space-limited portable applications. It operates from either a USB port or ac adapter and charges a single-cell, Li-Ion battery with up to 1.1 A of charge current. The bq25040 has a single-power output that charges the battery. A system load can be placed in parallel with the battery. The charge current is programmed using the ISET and EN/SET inputs. The charge current is programmable to USB100, USB500, or a user-programmed charge current up to 1.1 A. Additionally, a 4.9 V, 3%, 50 mA LDO is integrated into the integrated circuit (IC) for supplying low-power external circuitry. The single- input interface (EN/SET) is used to select the charge current and to place the bq25040 into Production Test Mode (PTM). In PTM, the bq25040 operates as a linear regulator without a battery connected, where the output is regulated at 4.2 V and supplies up to 2.3 A to calibrate GSM transceivers.
The battery is charged in three phases: conditioning, constant current, and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded.
The charger power stage and charge current sense functions are fully integrated. The charger function has accuracy current and voltage regulation loops, charge status display, and charge termination.