Switching Driver for Diving Flashlight DV-S9 Led Open Source Hardware.
This post explains the design of an adjustable switching regulator driver for DV-S9 diving flashlight, supporting current up to 1 A and input voltage between 3V and 4.2V, along with low standby current. The driver achieves up to 85% efficiency at maximum current. This design is open source hardware with design documents stored on Github.