Evaluates: MAX16815/MAX16828
MAX16828 Evaluation Kit
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Quick Start
Recommended Equipment
Before beginning, the following equipment is needed:
• 0 to 30V or above, 0.5A DC power supply
Procedure
The MAX16828 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Connect a 0 to 30V or above, 0.5A DC power
supply to VIN.
2) Verify that a shunt is installed on JU1.
3) Turn on the power supply and increase the input
voltage to above 6.5V. Measure the LED current
between the LED+ and LED- pads to show 200mA
±3.5%.
4) Measure voltage across test point V5 to show 5V
±4%.
Detailed Description of Hardware
The MAX16828 EV kit demonstrates a current-con-
trolled, high-output-current LED driver with accurate
current control based on the MAX16828 current regula-
tor. This EV kit is configured for supplying regulated
output currents of 100mA to 200mA. The EV kit can
operate from a single power supply at voltages
between 6.5V and 40V.
The EV kit also features pulse-width modulation (PWM)
dimming control and provides a test point (V5) for con-
venient access to the 5V regulated output.
Output Current (LED+, LED- )
The output current for the standard output (between
LED+ and LED- pads) can be set at either 100mA or
200mA by installing or removing jumper JU1. See
Table 1 for jumper settings. By default, the output cur-
rent is 200mA.
Setting the Output Current
The output current can be adjusted by replacing resis-
tors R2 or R3 with values calculated using the following
equation:
where R
SENSE
is the external current-sense resistance
between CS+ and GND, I
LED
is the desired output cur-
rent, and V
RSENSE
is 200mV (typ).
PWM Dimming
The PWM dimming controls the LED brightness by
adjusting the duty cycle of the PWM input signal con-
nected to the DIM input. A high at the DIM input turns
on the output current and a low turns off the output cur-
rent. Connect a signal with peak amplitude between 5V
and 40V, and with frequency between 100Hz to 2kHz
and vary the duty cycle to adjust the LED brightness.
LED brightness increases when duty cycle increases
and vice versa. Duty cycle can be as low as 10%, even
at a PWM frequency of 2kHz.
5V Regulated Output
The 5V regulator can be used to power other compo-
nents from the V5 test point. The 5V output can supply
up to 4mA of current and is not disabled during PWM off.
