EVB10803 Melexis Company, EVB10803 Datasheet - Page 3

• Manufacturer Part Number: EVB10803
• Description: Evaluation Board Evb10803 Power Led Driver For Automotive Applications
• Manufacturer: Melexis Company

7.
For normal operation only a few connections are necessary. The supply line VBAT must be connected to
any standard DC supply. The input voltage should always be about 2V higher then the sum of all
LED forward voltages in order to keep the regulator working. The supply must be able to drive the peak LED
current that is defined with the IREF2 potentiometer.
The LED(s) is (are) connected to the board via a polarised plug to avoid incorrect connection.
8.
For details on the function of the LED driver circuit, please refer to the MLX10803 IC specification.
For standard applications without the use of PWM, the jumper JMP1 has to be set in order to supply the IC
directly from the VBAT line. This is the default setting.
The LED(s) must be connected to J2, anode to LED+ (Pin1) and cathode to LED- (Pin2).
Supply voltage (6..32V DC) is applied to J1, Pin1 while Pin2 is the corresponding GND connection.
The sense resistor R3 was selected in order to limit the maximum peak current to about 2 Ampere. That was done
to remain within the operation area (saturation current I
limited to values about 1.5 Ampere depending on the used settings. If higher currents are desired, care has to be
taken with the selection of coil and transistor and attention has to be drawn to the thermal behaviour of the board.
Dimming the average LED current is achieved by applying a PWM signal to the VS/PWM pin (J1, Pin3). In fact, the
IC is powered on and off according to the state of the duty cycle. Because of the maximum IC settling time, the
maximum PWM frequency is limited to 5kHz. The on voltage of the PWM signal must be 6..32V in order to power
the IC correctly. The PWM signal must be able to drive the IC’s supply current which is maximum 700µA @13.8V
and 2mA @32V.
390121080301
20/Mar/2006
Author: SSZ
Figure 3: Minimal board connections
Minimal Board Connections
Description
8.1.
8.2.
General
Using PWM
Rev. 5.01
Evaluation board EVB10803
Power LED driver for automotive applications
sat
) of the selected coil. Thus, the average LED current is
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