Texas Instruments LM3643EVM User Manual
Using the LM3643EVM Evaluation Module
User's Guide
Literature Number: SNVU399
August 2014
Contents
1 Introduction......................................................................................................................... 4
2 Setup.................................................................................................................................. 4
2.1 Input/Output Connector Description ................................................................................... 4
2.2 Setup....................................................................................................................... 6
2.3 Operation.................................................................................................................. 6
3 Board Layout....................................................................................................................... 7
4 Schematic ......................................................................................................................... 10
5 USB Interface Board and I
5.1 User Interface ........................................................................................................... 13
5.2 Flags...................................................................................................................... 14
5.3 I/O Pin Controls ......................................................................................................... 14
2
C-Compatible Interface Program .................................................... 12
2
Table of Contents SNVU399–August 2014
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1 Enable Jumper Settings..................................................................................................... 4
2 VIO Jumper Settings ........................................................................................................ 4
3 STROBE Jumper Settings.................................................................................................. 5
4 TORCH/TEMP Jumper Settings ........................................................................................... 5
5 TX Jumper Settings ......................................................................................................... 5
6 Jumper Configuration ....................................................................................................... 7
7 Top Assembly Layer......................................................................................................... 8
8 Middle Layer 1 Routing ..................................................................................................... 8
9 Middle Layer 2 Routing ..................................................................................................... 9
10 Bottom Assembly Layer (UNMIRRORED) ............................................................................... 9
11 LM3643EVM Schematic................................................................................................... 10
12 LM3643 General User Interface.......................................................................................... 12
13 I
14 Write Buttons................................................................................................................ 13
15 Flags ......................................................................................................................... 14
16 I/O Pin Controls............................................................................................................. 14
1 Device and Package Configurations ...................................................................................... 4
2 Bill of Materials ............................................................................................................. 11
List of Figures
2
C interface Fields ......................................................................................................... 13
List of Tables
SNVU399–August 2014 List of Figures
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LM3643EVM User's Guide
1 Introduction
The Texas Instruments LM3643EVM evaluation module (EVM) helps designers evaluate the operation
and performance of the LM3643 High-Current LED driver. The device offers configurability via I2Ccompatible interface. It can be enabled in Flash or Torch mode via the I2C interface or externally using the
STROBE and TORCH/TEMP pins. The module utilizes two LEDs (D1 & D2) mounted on the EVM.
The EVM contains one Synchronous Boost LED Flash Driver (See Table 1).
Table 1. Device and Package Configurations
FLASH LED DRIVER IC PACKAGE
U1 LM3643 0.4 mm-pitch, 12-Bump DSBGA
2 Setup
This section describes the jumpers and connectors on the EVM as well as how to properly connect, set
up, and use the LM3643EVM.
User's Guide
SNVU399–August 2014
2.1 Input/Output Connector Description
Input / GND - These are the power input terminals for the driver. The terminal block provides a power
(VIN) and ground (GND) connection to allow the user to attach the EVM to a cable harness.
EN (J12) - This is the jumper used to enable the LED driver (HWEN pin). The driver will be enabled when
the HWEN pin is high (VIO) and disabled when it is low (GND).
Figure 1. Enable Jumper Settings
VIO (J16) - This pin provides power for the I2C lines (Clock & Data) and for the HWEN pin. It is
recommended that this pin is connected to the VIN pin. If desired, it can be connected to the 3.3V line
provided by the USB interface connector. In this configuration, communication via the I2C interface may
not be possible if the supply voltage to the LED driver is below approximately 3 V.
Figure 2. VIO Jumper Settings
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LM3643EVM User's Guide SNVU399–August 2014
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D1-CON (J14 pin3 and pin4) and D2-CON (J14 pin1 and pin2) are the jumpers used to connect the onboard flash LEDs to the LED output of the driver.
STROBE (J9) - This pin provides an external method for initiating a flash event. The STROBE pin is
connected to ground via a 300-kΩ resistor internal to the LM3643. To externally drive this pin, either
connect a control signal directly to the STROBE pin of the connector or place a jumper between connector
pins STROBE and PWM0. Pin PWM0 can be configured as a time-adjustable voltage pulse via the
General User Interface (GUI) software provided.
TORCH/TEMP (J21) - This pin provides an external method for initiating a torch event. The
TORCH/TEMP pin is connected to ground via a 300-kΩ resistor internal to the LM3643 as well as an
externally connected NTC thermistor. To externally drive this pin, either connect a control signal directly to
the TORCH/TEMP pin of the connector or place a jumper between connector pins TORCH/TEMP and
PWM1. Pin PWM1 can be configured as ON or OFFvia the GUI software provided. Removing the jumper,
and setting the TORCH/TEMP pin to TEMP mode, the TEMP function can be utilized via the externally
connected NTC thermistor.
Setup
Figure 3. STROBE Jumper Settings
Figure 4. TORCH/TEMP Jumper Settings
TX (J11) - This pin is used to initiate a TX-interrupt event. The TX pin is connected to ground via a 300-kΩ
resistor internal to the LM3643. To externally drive this pin, either connect a control signal directly to the
TX pin of the connector or place a jumper between connector pins TX and PWM2. Pin PWM2 can be
configured as to provide continuous voltage pulses via the GUI software provided.
Figure 5. TX Jumper Settings
SDA / SCL (J19) - These connections allow the user to externally control the I2C lines. For independent
control of the I2C lines, do not connect the VIO jumper to either the 3.3 V or the VIN pin.
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Setup
OUT, LED1, LED2, TORCH/TEMP (J13, J10, J22) - These provide access to the regulated output of the
driver, the outputs of the LED current sources, and the TEMP pin. The user can measure VOUT with
reference to GND, VLED with reference to GND, current source headroom directly between VOUT and
VLED, and can monitor or control TORCH/TEMP input.
VINL/VIN (J7) - The user can monitor the Inductor Current and Input Current waveforms by omitting this
jumper and using separate wires from the power supply to the VINL and VIN pins. This will remove the
Input Capacitors from the Inductor and eliminate their filtering effect to the Inductor Current.
J17 and J18: LED Current measurements -The LM3643EVM provides a way to accurately measure the
LED current through both LEDs on board. Resistors R1 & R2 (0.1 Ω) are placed between the cathode of
LED1 & LED2, respectively, and Ground. The user can first measure the resistor values accurately, by
applying a known current through connector DxF and Ground and measuring the voltage between DxS
and GNDS. Then, during normal flash or torch operation, the voltage measured across the resistor divided
by the resistor value will equal the current through the resistor (and the LED).
2.2 Setup
The input voltage range for the flash driver is 2.5 volts to 5.5 volts. The on-board LEDs or an LED module
should be connected for proper operation.
2.3 Operation
For proper operation of the LM3643EVM, the jumpers should be properly configured. The recommended
setting, using shorting blocks is:
VIO to VIN
EN to VIO
STROBE to PWM0 or external signal
TORCH/TEMP to PWM1 or external signal
TX to PWM2 or external signal
LEDs (J14) shorted
In this configuration, the device will power up when power is applied.
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LM3643EVM User's Guide SNVU399–August 2014
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