MAX16836 Evaluation Kit

2

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Quick Start

Recommended Equipment

Before beginning, the following equipment is needed:

• 0 to 30V or above, 0.5A power supply

Procedure

The MAX16836 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 DC power supply (0 to 30V or above,

0.5A) to VIN.

2) Verify that a shunt is not installed across jumper

JU1 to enable U1.

3) Verify that a shunt is installed across pins 1-2 of

jumper JU2 to select 350mA output current.

4) Connect a 350mA-rated LED between LED+ and

LED-.

5) Turn on the power supply and increase the input

voltage to above 6.5V. The LED should glow with

full brightness. Measure the LED current, which

should be 350mA

±3.5%.

6) Increase the supply voltage and measure the LED

current, which should be 350mA

±3.5%. Note that

the maximum voltage drop between IN and OUT

should be ~7V to limit the maximum power dissipa-

tion to approximately 2.5W.

7) Measure the voltage across V5, which should be

5V

±4%.

Detailed Description of Hardware

The MAX16836 EV kit demonstrates a high-output-

current LED driver with accurate current control based

on the MAX16836 current regulator. The MAX16836 EV

kit is capable of supplying regulated output currents of

up to 350mA and runs at supply voltages between

6.5V to 40V. If the supply voltage is above the LED

operating voltage by more than 7V, the maximum out-

put current should be limited to prevent the device

from entering into thermal shutdown due to excessive

power dissipation.

The MAX16836 EV kit features PWM dimming to control

the LED brightness by varying the duty cycle of the

PWM input signal. Users can select between three lev-

els of output LED currents by setting jumper JU2 (see

Table 1 for jumper settings). The MAX16836 EV kit also

includes a connection for the 5V regulated output and

access to the on-board current-sense resistor.

Output Current Setting

The output current can be adjusted by replacing resis-

tors R2 or R3 with values calculated using the following

equation:

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, frequency between 100Hz and 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 supplies up

to 4mA of current.

Jumper Selection

Two-pin jumper JU1 controls the EN pin of the

MAX16836 and enables or disables the device. Three-

pin jumper JU2 selects between three different output

current settings. Table 1 lists the jumper options.

V

I

SENSE

LED

SHUNT POSITION AND FUNCTION

JUMPER

1-2 (installed)

2-3

Open

JU1

U1 disabled

—

U1 enabled*

JU2

350mA*

250mA

150mA

Table 1. Jumper JU1 and JU2 Functions

*

Default position.