Datasheet
4 Maxim Integrated
Evaluates: MAX16833/MAX16833B
MAX16833 Evaluation Kit
Detailed Description of Hardware
The MAX16833 EV kit provides a proven design to evalu-
ate the MAX16833 high-voltage HB LED driver with inte-
grated high-side current sense. The EV kit is set up for
boost and buck-boost configurations and operates from
a 5V to 18V DC supply voltage. The EV kit is configured
to deliver up to 1A to a series LED string. The string for-
ward voltage can vary from 3V to 36V.
Analog Dimming Control (ICTRL)
When JU1 is installed, the ICTRL pin is connected to the
voltage-divider of R7 and R8, which sets the voltage at
ICTRL (V
ICTRL
) to 1.29V when input supply is above 7V
and 890mV when the input supply is 5V. When V
ICTRL
>
1.23V, the internal reference sets the LED current (I
LED
)
using the following formula:
LED
200mV
I
R4
=
In the case of the EV kit, I
LED
is set to 1A. If V
ICTRL
<
1.23V, then V
ICTRL
sets the LED current level.
Alternatively, the analog dimming can be controlled
by removing the shunt of JU1 and applying a voltage
between 0 and 5.5V on the ICTRL pad of the EV kit.
Pulse-Dimming Input (PWMDIM)
Pulse dimming can be achieved by applying a pulsating
voltage source on the PWMDIM pad of the EV kit. When
PWMDIM is pulled low, DIMOUT is pulled high and the
pulse-width modulated (PWM) switching is disabled.
Frequency Dithering (LFRAMP)
When JU3 is in the 2-3 position and JU2 is not installed,
frequency dithering is achieved.
Frequency Synchronization (RT/SYNC)
The devices can be synchronized to an external clock
by applying a synchronizing pulse on the RT/SYNC
input pin. Refer to the MAX16833/MAX16833B IC data
sheet for more information regarding synchronizing to an
external clock. Frequency dithering must be disabled for
external frequency synchronization.
Evaluating the MAX16833B
For evaluating the MAX16833B, replace the MAX16833
on the EV kit with a MAX16833B. The jumper configura-
tions are as follows: JU1 (open shunt position), JU2 (1-2
shunt position), JU3 (1-2 shunt position). See Table 1 for
details.