No Boost Inductor Design with LM364x for Long-Time Focusing in Camera Module

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1 Introduction

1.1 Key Specification of LM3644

2.5 V to 5.5 V Input Voltage Range
Dual Independent 1.5-A LED Current Source Up to 1500 mA per channel in Flash mode Programmability
Accurate and Programmable LED Current Range from 1.4 mA to 1.5 A
Torch Currents up to 360 mA (LM3644TT)
Flash Current up to 1500 mA
Support Flash Timeout function
Support Input Voltage Flash Monitor (IVFM)
Size: 1.69mm × 1.31mm, DSBGA (12)

1.2 LM3644 Simplified Block Diagram

LM3644 can support most of hero LED vender products in the market so as to make LED flash driving design more easily. It can support up to 2 channel LED flashing or torching with 1.5-A maximum flash current and 360 mA (LM3644TT) torch current per each channel. LM3644 also supports flash timeout and IVFM to keep flash LED and system always being in safe.

Figure 1-1 LM3644 LED Flash Driver