Only For Training And Service Purposes - LG KF510C Service Manual

Table of Contents

CAMERA FLASH LED

The SM8152A switches between 3 charge pump operating modes; x1 mode (VIN through mode), x1.5

mode(x1.5 charge pump boost), and x2 mode (x2 charge pump boost), reducing the total power

dissipation. These switching occurs automatically in internal circuits, and cannot be controlled by

external signals. If the LED current drops below the setting value while operating in x1 or x1.5 mode,

each LED drive circuit detects the undercurrent condition and the operating mode is automatically

switched x1 → x1.5, x1.5 → x2. This occurs even if only one LED undercurrent condition is detected

among the 5-channel LED drive circuits, thus it is recommended that LED has small VF variation to

optimize the total efficiency. In x1.5 or x2 mode operating, the SM8152A generates "a mode reset

signal" internally once every 1 second. This signal forces to switch the mode x1.5 → x1, x2 →σ x1.5.