Maxim Integrated
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3
MAX16813 Evaluation Kit Evaluates: MAX16813/MAX16813B
www.maximintegrated.com
Quick Start
Required Equipment
● MAX16813EVkit
● 6.5Vto40V,4ADCpowersupply
● Digitalvoltmeter
● Fourseries-connectedHBLEDstringsratednoless
than 150mA
● CurrentprobetomeasuretheHBLEDcurrent
Output Testing
The 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) Verify that a shunt is installed on jumper JU1 and
across pins 1-2 on jumper JU2 (device enabled).
2) Verify that a shunt is installed on jumper JU3 (150mA
HB LED current-sink limit).
3) Verify that shunts are not installed on jumpers
JU4–JU7 (all channels powered).
4) Connect the power supply to the VIN PCB pad and
the power supply’s ground to the PGND PCB pad.
5) Connect the digital voltmeter across the OUT1 and
PGND PCB pads.
6) Connect each HB LED string as follows:
Channel 1: Connect an HB LED string anode to
the VOUT PCB pad and the cathode to the OUT1
PCB pad.
Channel 2: Connect an HB LED string anode to
the VOUT PCB pad and the cathode to the OUT2
PCB pad.
Channel 3: Connect an HB LED string anode to
the VOUT PCB pad and the cathode to the OUT3
PCB pad.
Channel 4: Connect an HB LED string anode to
the VOUT PCB pad and the cathode to the OUT4
PCB pad.
7) Clip the current probe across the channel 1, HB LED+
wire to measure the HB LED current.
8) Turn on the power supply and set to 10V.
9) Measure the voltage from the OUT1–OUT4 PCB
pads to SGND and verify that the lowest voltage is
approximately 1.1V.
10) Measure the HB LED current using the current probe
and verify all channels.
Detailed Description of Hardware
The MAX16813 EV kit demonstrates the MAX16813 HB
LED driver with an integrated step-up DC-DC preregulator
followed by 4 channels of linear current sinks. The pre-
regulator switches at 350kHz and operates as a current-
mode-controlled regulator providing up to 600mA for the
linear circuit while providing OVP. Cycle-by-cycle current
limit is set by resistor R4 while resistors R6 and R7 set
the OVP voltage to 33V. The preregulator power section
consists of inductor L2, MOSFET Q3, power sense resis-
tor R4, and switching diode D1.
The EV kit circuit operates from a DC supply voltage of
6.5V up to the HB LED forward string voltage. The circuit
handles load-dump conditions up to 40V.
The EV kit circuit demonstrates ultra-low shutdown
current when the EN pin of the device is pulled to ground
by shorting the ENABLE PCB pad to ground. The EV kit
also demonstrates output short protection and recovery
from short. This can be tested by shorting the VOUT PCB
pad to the PGND PCB pad.
Each of the 4 linear channels (OUT1–OUT4) is capable
of operating up to 40V and sink up to 150mA per channel.
Each of the 4 channel’s linear current sinks is configurable
for 150mA or 100mA, or can be disabled independently.
Jumpers JU4–JU7 provide the disable feature when the
HB LED string is not connected. See the Channel 1–
Channel 4 Current-Sink Disabling section. Resistors R15,
R16, and jumper JU3 configure the linear current setting
for the device’s SETI pin, which sets the HB LED string
current.The EV kit features PCB pads to facilitate connect-
ing HB LED strings for evaluation. The VOUT PCB pads
provide connections for connecting each HB LED string’s
anode to the DC-DC preregulator output. The OUT1–
OUT4 PCB pads provide connections for connecting each
HB LED string’s cathode to the respective linear channel’s
current sink. Additionally, 2-pin headers (JU8–JU11)
provide convenient access to the VOUT and respective
OUT_ connections when using a twisted-pair wiring-
connection scheme. On each header, pin 1 provides
access to the respective OUT_ connection and pin 2
provides access to the VOUT connection. Capacitors
C18–C21 are included on the design to prevent oscil-
lations and provide stability when using long, untwisted
HB LED-connecting cables during lab evaluation. These
capacitors are not required on a typical HB LED design.
A DIM PCB pad is provided for using a digital PWM
signal to control the brightness of the HB LEDs. The EV
kit can also demonstrate the device’s synchronizing fea-
ture using the SYNC PCB pad and an external AC clock