LM3643 Texas instruments

LM3643

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LM3643

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Описание

The LM3643 is a dual LED flash driver that provides a high level of adjustability within a small solution size. The LM3643 utilizes a 2-MHz or 4-MHz fixed-frequency synchronous boost converter to provide power to the dual 1.5-A constant current LED sources. The total LED current the LM3643 boost can deliver is 1.5 A (ILED1 + ILED2 ). The dual 128 level current sources provide the flexibility to adjust the current ratios between LED1 and LED2 with each driver capable of delivering a maximum of 1.5 A (ex: ILED1 = 1.5 A and ILED2 = 0FF, ILED1 = 0FF and ILED2 = 1.5 A, or a current configuration with a current less than 1.5 A , ILED1 = 950 mA and ILED2 = 250 mA). An adaptive regulation method ensures the current sources remain in regulation and maximizes efficiency. Features of the LM3643 are controlled via an I2C-compatible interface. These features include: hardware flash and hardware torch pins (STROBE and TORCH/TEMP), a TX interrupt, and an NTC thermistor monitor. The device offers independently programmable currents in each output leg to drive the LEDs in a Flash or Movie Mode (Torch) condition. The 2-MHz or 4-MHz switching frequency options, overvoltage protection (OVP), and adjustable current limit allow for the use of tiny, low-profile inductors and (10-µF) ceramic capacitors. The device operates over a –40°C to 85°C ambient temperature range.

1.5 A Total Allowed LED Current During Operation
(I_LED1 + I_LED2 = 1.5 A)
Dual Independent LED Current Source Programmability
Accurate and Programmable LED Current Range from
1.4 mA to 1.5 A
Optimized Flash LED Current During Low Battery
Conditions (IVFM)
> 85% Efficiency in Torch Mode (@ 100 mA) and
Flash Mode (@1 A to 1.5 A)
Grounded Cathode LED Operation for Improved Thermal
Management
Small Solution Size: < 16 mm²
Hardware Strobe Enable (STROBE)
Synchronization Input for RF Power Amplifier Pulse
Events (TX)
Hardware Torch Enable (TORCH/TEMP)
Remote NTC Monitoring (TORCH/TEMP)
400-kHz I²C-Compatible Interface
- LM3643 (I²C Address = 0x63)
- LM3643A (I²C Address = 0x67)

Input voltage type	DC/DC
Topology	Boost, current mode
Vin (min) (V)	2.5
Vin (max) (V)	5.5
Vout (max) (V)	5.5
Vout (min) (V)	2.5
Iout (max) (A)	1.5
Iq (typ) (mA)	0.3
Features	I2C control, IR Mode
Operating temperature range (°C)	-40 to 85
Dimming method	Analog, PWM
Number of channels	2
Rating	Catalog