View hm4057c-e datasheet:

 HM4057C Standalone Linear Li-Ion Battery Charger with Thermal Regulation ■ General Description ■ Features The HM4057C is a c omplete constant-current /constant  Programmable charge current up to 500mA -voltage linear charger for single cell lithium-ion batteries.  No MOSFET, sense resistor or blocking diode Its ThinSOT package and l ow external component count required make the HM4057C ideally suited for portable applications.  Complete linear charger in thinsot package for single Furthermore, the HM4057C is specifically designed to work cell lithium-ion batteries within USB power specifications.  Constant-current/constant-voltage operation with No external sense resistor is needed, and no blocking thermal regulation to maximize charge rate without di