MAX16831EVKIT+ Maxim Integrated Products, MAX16831EVKIT+ Datasheet - Page 3

• Manufacturer Part Number: MAX16831EVKIT+
• Description: KIT EVAL FOR MAX16831
• Manufacturer: Maxim Integrated Products

Specifications of MAX16831EVKIT+

• Current - Output / Channel: 1A
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 28V
• Features: Dimmable
• Voltage - Input: 9 ~ 40V
• Utilized Ic / Part: MAX16831
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6) Clip the current probe across the LED+ wire to mea-
7) Turn on the power supply and increase the input
8) Adjust potentiometer R14 to obtain the desired LED
9) Measure the voltage between the LED+ and LED-
The MAX16831 evaluation kit (EV kit) demonstrates the
MAX16831 current-mode HBLED driver IC. The
MAX16831 EV kit is configured in a step-down/step-up
(buck-boost) topology with peak current control and
average current control for a string of user-supplied
external HBLEDs. The MAX16831 EV kit operates from a
DC supply voltage of 9V to 40V and requires up to 4A.
The circuit is configured to deliver 1A of current into
series LED string with a maximum 28V forward voltage.
The EV kit sets the maximum series inductor current to
8.3A using parallel resistors R6 and R7. The average
LED current is set to 1A using resistor R3. A CLKOUT
PCB pad is available to monitor the oscillator frequen-
cy. A DIM PCB pad is also provided for PWM dimming
operation of the external LEDs and to monitor the ana-
log DC voltage applied at the MAX16831 IC DIM pin.
The MAX16831 EV kit’s UVLO threshold is configured to
8.3V using resistors R1 and R2. The UVEN PCB pad
can be used to disable the EV kit circuit by connecting
UVEN to AGND. To configure the circuit to a different
UVLO threshold, refer to the Setting the UVLO
Threshold section in the MAX16831 IC data sheet.
The parallel combination of current-sense resistors R6
and R7 sets the EV kit’s peak inductor current limit to
8.3A. Use the following equation to calculate the total
resistance needed to reconfigure the inductor peak
current limit:
where I
the total parallel resistance placed at the R6 and R7
PCB pads.
Refer to the ILIM and HICCUP Comparator section in
the MAX16831 IC data sheet for additional information
on setting the peak current-limit threshold.
sure the LED current.
voltage to 9V.
current duty cycle.
PCB pads.
PEAK
Peak Inductor Current-Limit Setting
is the inductor peak current and R
Undervoltage Lockout (UVLO)
R
_______________________________________________________________________________________
TOTAL
Detailed Description
=
160
I
PEAK
mV
TOTAL
is
MAX16831 Evaluation Kit
Resistor R3 sets the MAX16831 EV kit average LED
current to 1A. Use the following equation to calculate
R3 when reconfiguring the LED current:
where I
LED dimming can be achieved on the MAX16831 EV kit
by applying a digital PWM signal or an analog DC volt-
age at the DIM PCB input pad. Jumper JU1, poten-
tiometer R14, resistor R15, and capacitor C15 configure
the MAX16831 EV kit for analog-control PWM dimming
operation.
Place a shunt across jumper JU1 to set the EV kit for
analog-control PWM dimming and adjust potentiometer
R14. The analog DC voltage at the DIM PCB pad sets
the duty cycle of the LED current, which controls the
external LED brightness. The MAX16831 IC DIM pin
voltage can be monitored by placing a voltmeter across
the DIM and AGND PCB pads.
Use the following equation to calculate the voltage at
the DIM PCB pad, which is necessary to program the
LED output current duty cycle, D:
where DIM is the analog DC voltage at the MAX16831
EV kit DIM PCB pad in volts, and D is the duty cycle of
the LED output current.
When operating the MAX16831 EV kit with analog-con-
trol PWM dimming, the LED dimming frequency is inter-
nally set by the MAX16831 IC to 200Hz.
Remove the shunt at jumper JU1 to control LED dim-
ming using a digital PWM signal at the DIM PCB pad.
Apply a digital PWM signal with a 3.2V to 15V logic-high
level in the 80Hz to 2kHz frequency range and adjust
the duty cycle to adjust the LED brightness. See Table
1 for jumper JU1 setting for LED dimming operation.
Table 1. MAX16831 LED Dimming
Operation (Jumper JU1)
SHUNT POSITION
Not installed
Installed
LED
is the LED current.
DIM
Setting External LED Current
Analog DC voltage adjusted using R14
≅
R
PWM signal applied at DIM PCB pad
(
3
D
EV KIT DIMMING OPERATION
=
×
107
2 6
I
LED
LED Dimming Control
.
mV
V
)
+
0 2
.
V
3