View hm3415 datasheet:

 3415 Features General Description   Th is a high- efficiency monolithic synchronous  1.5MHz Constant Frequency Operation buck regulator using a constant frequency, current mode  No Schottky Diode Required architecture. The device is available in an adjustable  Low Dropout Operation:100% Duty Cycle version. Supply current with no load is 40uA and drops  PFM Mode for High Efficiency in Light Load to <1uA in shutdown. The 2.5V to 6V inp ut voltage  Over temperature Protected range makes the HM3415 ideally suited for single Li- Ion  Low Quiescent Current: 40μA battery powered applications. 100% duty cycle provides Short Circuit Protection  low dropout operation, extending battery life in portable Inrush Current Limi