Circuit design: rechargeable electric screwdriver
Summary
Only one SLG47105 allows us to create a complete device with charging control, motor driving, overcurrent protection, and other interface features. In this case, a closed loop system controls the PWM duty cycle to ensure the constant average output voltage level. In this case, the ACMP0 controls the constant voltage of 4.2V and the CCMP1 just checks and keeps the current decreasing and lower than 90 mA until the battery is fully charged. The results prove that the circuit works as expected, and the SLG47105 is capable of acting as the control module for the 3V DC-DC Motor and 3.7V Li-ion battery charger at the same time. The SLG47105 internal resources, including the HV part, oscillators, logic, and GPIOs are easy to configure to implement the desired functionality for this design.