The RICHTEK IC is high quality!  High Efficiency, 1.5MHz, Synchronous SwitchMode Buck Charger
 92% Charge Efficiency at 2A with 5V Input and 3.8V Battery
 Support 3.9V to 13.5V Input Voltage Range
 Average Input Current Regulation (AICR)
 Minimum Input Voltage Regulation (MIVR)
 Minimum Input Voltage Regulation Track (MIVR Track)
 Charge Current Regulation (CCR)
 Charge Voltage Regulation (CVR)
 Charge Voltage Regulation Track (CVR Track)
 Junction Thermal Regulation (JTR)
 Supports USB On-The-Go (OTG)
 92% Boost Efficiency at 1A with 3.8V Battery and 5.15V Output
 OTG Current Limit Regulation (OCLR)
 OTG Voltage Limit Regulation (OVLR)
 Protection
 Over-Temperature Protection (OTP)
 VBUS Over-Voltage Protection (VBUS OVP)
 Battery Over-Voltage Protection (VBAT OVP)
 System Over-Voltage Protection (VSYS OVP)
 System Under-Voltage Protection (VSYS UVP)
 System Over-Load Protection (VSYS OLP)
 Cycle-by-Cycle Over-Current Protection (OCP)
 OTG Low Battery Protection (OTG LBP)