A novel Li-ion battery charger using multi-mode LDO configuration based on 350 nm HV-CMOS

The design of a novel Li-ion battery charger using multi-mode LDO architecture has been introduced in this paper. The proposed architecture, using an improved multi-mode LDO, not only obtains high accuracy but also reduces power supply noise because of utilizing novel error amplifier and power buffer configuration; while still consuming low power dissipation. To obtain the low power consumption, the Schmitt Trigger technique is applied to the charging controller and an optimized current driven circuit is proposed. Besides, the PSRR parameter is also enhanced by adding pre-regulation circuit in multi-mode LDO circuit. Thus, the proposed Li-ion battery charger achieves 700 mA operation current with 70.9 % efficiency but only dissipates 495 mW in power. During the charging process, the setting time and ripple issues are solved by the use of soft-start circuit which is integrated into the charging controller in order to decrease the chip area. Therefore, the setting time is reduced to 5.5 μs while gaining the load regulation at approximately 0.019 μV/mA and increasing PSRR up to 106 dB at DC level. Moreover, the line regulation is also reduced at 1.3 mV/V. The proposed linear battery charger is designed and implemented, based on High-Voltage CMOS process with using 4.5 V power supply voltage and obtaining 4.2 V battery output voltage.