Analyze the voltage error of the lithium battery charger caused by the PCB wiring error

The voltage error between the lithium battery charger and the battery terminals may be caused by the voltage drop across the connector, cable or PCB wiring during charging. Therefore, the accuracy of the lithium battery charging voltage should be at least 1%. For example, a copper wire with a width of 0.238 cm (3/32 inch) has a resistance of 14 meters per inch. If the charging current of the lithium battery is 600 mA and must be placed at a distance of 10.16 cm (4 inches) from the charger, the wiring will cause a voltage error of 34mV (about 8% of the 4.2v floating voltage of the lithium battery). In addition, this voltage error can cause the charger to terminate the fast charge (constant current) cycle prematurely. If you choose to end the charging cycle in 2h, the lithium battery will only be partially charged, leading to more frequent charging. If the charger stops charging after reaching a specific charging current (such as 1/10 of the fast charging current), then the lithium battery needs more time to charge. In order to eliminate this charging inaccuracies, the charger should be able to perform kel-vin testing (sometimes called telemetry) on the lithium battery terminal. The Kelvin test allows the charger's error amplifier to measure the voltage at the lithium battery terminals and compensate for voltage errors caused by PCB wiring or cable impedance. After eliminating this voltage error, when the lithium battery and charger are to be placed relatively far away, higher charging voltage accuracy can be obtained. LTC4058 is an independent lithium battery charger with Kelvin detection function. Its dedicated BSENSE pin monitors the voltage of the lithium battery terminal to compensate for voltage errors caused by PCB wiring or cable impedance under high charging currents. By combining an accurate voltage reference and remote measurement of the battery terminal voltage, the LTC4058 achieves a floating lithium battery voltage with an accuracy of ±1% of the current. The charger can also supply up to 950mA of charging current for a single lithium battery. LTC4058 also has protection functions such as overvoltage, soft start, overheating and reverse current, as well as monitoring functions such as pre-check and automatic charging of lithium batteries. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Use and maintenance tips for lithium battery charging