MAX16813 Evaluation Kit
Evaluates: MAX16813/MAX16813B
General Description
The MAX16813 evaluation kit (EV kit) demonstrates
the MAX16813 high-brightness LED (HB LED) driver,
integrating a step-up DC-DC preregulator followed by 4
channels of linear current sinks. The step-up preregulator
switches at 350kHz and operates as a current-mode-
controlled regulator capable of providing up to 600mA
for the linear circuits. Each of the 4 linear channels are
capable of operating up to 40V and provide up to 150mA
per channel. The 4 channels are configurable for 100mA
or 150mA HB LED output current.
The EV kit operates from a 6.5V DC supply voltage up
to the HB LED string-forward voltage. The EV kit can
withstand a 40V load-dump condition for up to 400ms.
The EV kit demonstrates the device features such as
adaptive voltage optimization, undervoltage lockout
(UVLO), overvoltage protection (OVP), cycle-by-cycle
current limit, thermal shutdown, and digital PWM dimming
operation using a digital PWM input signal to control the
brightness of the HB LEDs. The EV kit includes an external
pMOSFET (Q2) that can be used to disconnect the boost
output from the battery in the event of an output overload
or short condition.
The MAX16813 EV kit can also be used to evaluate the
MAX16813B with simple IC replacement of U1.
Benefits and Features
● Demonstrates OVP (33V)
● 6.5V Up to HB LED Forward Voltage
● HB LED String Output Currents Configurable for
100mA or 150mA
● Demonstrates UVLO (4V)
● Demonstrates Cycle-by-Cycle Current-Limit and
Thermal-Shutdown Features
● Demonstrates Adaptive-Voltage Optimization
● Demonstrates Output Short Protection and
Ultra-Low Current Shutdown
● Proven PCB and Thermal Design
● Fully Assembled and Tested
Ordering Information
appears at end of data sheet.
Component List
DESIGNATION
C1, C23
QTY
2
DESCRIPTION
4.7µF ±10%, 50V X7R ceramic
capacitors (1210)
Murata GRM32ER71H475K
47µF, 50V electrolytic capacitor
(6.3mm x 7.7mm Case)
SANYO 50CE47KX
1µF ±10%, 50V X7R ceramic
capacitors (0805)
Murata GRM21BR71H105K
33µF, 50V electrolytic capacitor
(6.3mm x 7.7mm Case)
SANYO 50CE33KX
Not installed, electrolytic
capacitor (6.3mm x 7.7mm Case)
DESIGNATION
C8, C13–C16
C9, C11
QTY
0
2
DESCRIPTION
Not installed, ceramic capacitors
(0603)
1000pF ±5%, 25V C0G ceramic
capacitors (0603)
Murata GRM1885C1E102J
0.022µF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H223K
47pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H470J
2200pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H222J
C2
1
C3, C4, C7,
C12
C10
1
4
C17
1
C5
C6
1
0
C18–C21
4
19-6770; Rev 1; 12/17
MAX16813 Evaluation Kit
Evaluates: MAX16813/MAX16813B
Component List (continued)
DESIGNATION
C22
D1, D3
QTY
1
2
DESCRIPTION
0.047µF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H473K
60V 1A Schottky diodes (SMB)
Diodes Inc. B160B-13-F
75V, 250mA high-speed diode
(SOT23)
Central Semi CMPD914E
(Top Mark: C5DE)
18V zener diode (DO-214AC)
Vishay BZG03C18TR
0Ω resistor (1210)
2-pin headers
3-pin header
10µH ±20%, 3A inductor
Coilcraft MSS1048-103ML
22µH ±20%, 5A inductor
Coilcraft MSS1260-223Ml
Miniature red PC test points
40V, 200mA pnp transistor
(3 SOT23)
Diodes Inc. MMBT3906-7-F
60V, 55A p-channel MOSFET
(D2PAK)
Vishay SUM55P06-19L-E3
40V, 9A n-channel MOSFET
(8 SO)
International Rectifier IRF7469
DESIGNATION
R1
R2
R3
R4
R5
R6
R7
R8, R9
R10
R11
R12
R13
R14, R15
R16
R17
R18
R19
R20
R21
SGND
U1
—
—
*EP
= Exposed pad.
QTY
1
1
1
1
1
1
1
2
1
1
1
1
2
1
0
1
1
0
1
1
1
7
1
DESCRIPTION
10kΩ ±5% resistor (0603)
1MΩ ±5% resistor (0603)
22Ω ±5% resistor (0805)
0.1Ω ±1%, 0.5W resistor (2010)
IRC LRC-LRF2010LF-01-R100-F
2.4kΩ ±1% resistor (0805)
261kΩ 1% resistor (0805)
10kΩ ±1% resistor (0805)
10kΩ ±5% resistors (0805)
30.1kΩ ±1% resistor (0805)
20kΩ ±1% resistor (0805)
200Ω ±1% resistor (0603)
21kΩ ±1% resistor (0603)
15kΩ ±1% resistors (0805)
30.1kΩ ±1% resistor (0805)
Not installed, resistor (0603)
1kΩ ±5% resistor (0805)
1.4kΩ ±1% resistor (0805)
Not installed, resistor
0.1Ω ±1, 0.5W current-sense
resistor (1206)
IRC LRC-LR1206LF-01-R100-F
Miniature black PC test point
4-channel HB LED driver
controller (20 TQFN-EP*)
Maxim MAX16813ATP/V+
Shunts
PCB: MAX16813 EVKIT
D2
1
D4
FB1
JU3–JU11
JU2
L1
L2
OVP, PGATE,
VCC
Q1
1
1
9
1
1
1
3
1
Q2
1
Q3
1
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MAX16813 Evaluation Kit
Evaluates: MAX16813/MAX16813B
Quick Start
Required Equipment
● MAX16813 EV kit
● Digital voltmeter
● Four series-connected HB LED strings rated no less
than 150mA
● Current probe to measure the HB LED current
● 6.5V to 40V, 4A DC power supply
Detailed Description of Hardware
Output Testing
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
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.
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MAX16813 Evaluation Kit
Evaluates: MAX16813/MAX16813B
signal. Test points are also provided for easy access to
the device’s V
CC
and SGND.
Enable
The EV kit features an enable input that can be used to
enable and disable the device and place it in shutdown
mode. To enable the EV kit whenever power is applied
to VIN and PGND, place the jumper across pins 1-2 on
jumper JU2.
To enable the EV kit from an external enable signal, place
the jumper across pins 2-3 on JU2. In this configuration,
apply a logic signal on the ENABLE input pad on the EV
kit. The enable EN input should not be left unconnected.
Refer to the
Enable
section in the MAX16813 IC data
sheet for additional information. See Table 1 for jumper
JU2 settings.
is the new resistor value for obtaining the desired HB LED
current. Remove jumper JU3 when configuring for another
current-sink threshold. If the HB LED current is reconfig-
ured for a different current, other components on the EV kit
may need to be modified. Refer to the MAX16813 IC data
sheet to calculate other component values.
Channel 1–Channel 4 Current-Sink Disabling
The EV kit features jumpers JU4–JU7 to disable each
channel’s OUT_ current sink. To disable a channel,
install a jumper in the channel’s respective OUT_ jump-
er. Remove the shunt to use a channel’s OUT_ sink
capability. See Table 3 for JU4–JU7 jumper settings.
HB LED Digital Dimming Control
HB LED Current
The EV kit features jumper JU3 to reconfigure the
device’s current sinks on all 4 channels. Place a shunt on
jumper JU3 to configure the current-sink limits to 150mA.
Remove the shunt from JU3 to configure the current-sink
limits to 100mA. See Table 2 for jumper JU3 settings.
To reconfigure the circuit for another current-sink thresh-
old, replace resistor R15 and use the following equation to
calculate a new value for the desired current:
R15
=
1500
I
LED
The EV kit features a DIM PCB input pad for connect-
ing an external digital PWM signal. The DIM PCB pad
is pulled up to VCC by resistor R8. Apply a digital PWM
signal with a 0.8V logic-low (or less) 2.1V logic-high (or
greater) level, and frequencies from 100Hz to 20kHz. To
adjust the HB LED brightness, vary the signal duty cycle
from 0 to 100% and maintain a minimum pulse width
of 500ns. Apply the digital PWM signal to the DIM and
SGND PCB pads. Refer to the
LED Dimming Control
section in the MAX16813 IC data sheet for additional
information on the device’s dimming feature.
FLT
and RT (External Clock Synchronizing)
Signals
where I
LED
is the desired HB LED current in amps and R15
The EV kit features the device’s
FLT
and AC-coupled RT
signals. The
FLT
signal is pulled up to VCC by resistor R9.
Table 1. Enable (JU2)
SHUNT POSITION
1-2*
2-3 (ENABLE test pad shorted to SGND)
2-3 (ENABLE test pad connected to an external controller)
*Default position.
EN PIN
Connected to IN
Connected to SGND
Connected to an external
controller
EV KIT OPERATION
Enabled
Disabled
External controller enabled
Table 2. HB LED Current (JU3)
SHUNT POSITION
Not installed
Installed*
*Default position.
SETI PIN
Connected to R15
Connected to R15 and R16
HB LED CURRENT-SINK LIMITS (mA)
100
150
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MAX16813 Evaluation Kit
Evaluates: MAX16813/MAX16813B
An open-drain fault flag output (FLT) goes low when
an open-LED string is detected, a shorted-LED string
is detected, an output undervoltage, or during thermal
shutdown. Refer to the
Fault Protections
section in the
MAX16813 IC data sheet for additional information on the
FLT
signal.
The SYNC PCB pad is used for connecting an external
clock for synchronizing the device’s switching frequency
through its RT pin. The signal must also have a 4V
P-P
amplitude and frequencies from 390kHz to 410kHz.
Apply the external clock signal to the SYNC and SGND
PCB pads. Refer to the
Oscillator Frequency/External
Synchronization
section in the MAX16813 IC data sheet
for additional information on the device’s synchronizing
feature.
LED Management and Overvoltage Protection
section in
the MAX16813 IC data sheet for additional information on
the OVP feature.
Output Short Protection
OVP Configuration
The device’s OVP resistors (R6 and R7) are configured
for an OVP of 33V. This sets the maximum channel
(VOUT) voltage at 33V. Capacitor C9 provides noise
filtering to the OVP signal. To reconfigure the circuit for a
different OVP voltage, replace resistor R6 with a different
value using the following equation:
OVP
=
R6
−
1
×
R7
1.23V
where R7 is 10kΩ, OVP is the overvoltage-protection volt-
age desired, and R6 is the new resistor value for obtaining
the desired overvoltage protection. Refer to the
Open-
The boost output appearing at VOUT can be shorted
to PGND without any damage. This can be tested at
power-up or it can also be done at any time during normal
operation by shorting the VOUT PCB pad to PGND. The
ENABLE PCB pad can be connected to IN by installing
jumper JU2 from pins 1-2. When the unit is powered
up with a short on VOUT to PGND, resistor R21 in
conjunction with the transistor Q1 limits the current that
can flow in Q2 once it is turned on. The current is limited
to VBE(Q1)/R21. This current flows for 33ms (typ) into
the short after power-up. Refer to the
Startup Sequence
section in the MAX16813 IC data sheet for more informa-
tion. After 33ms of power-up, the IC is disabled and the
external MOSFET Q2 is turned off. The IC is then latched
off and ENABLE has to be recycled, or input power has
to be recycled, to resume operation after the short is
removed.
The VOUT PCB pad can also be shorted to PGND at any
time during normal operation. An output short causes the
voltage on the OVP pin to go below 0.585mV resulting in
an output undervoltage, which causes the PGATE pin to
go high and disconnects the external MOSFET Q2 from
the input. The
FLT
pin also goes low in the case of a short
on the output.
Table 3. Disabling Channel 1–Channel 4 (JU4–JU7)
OUT_
OUT1
OUT2
OUT3
OUT4
JUMPER
JU4
JU5
JU6
JU7
SHUNT POSITION
Not installed
Installed
Not installed
Installed
Not installed
Installed
Not installed
Installed
CHANNEL OPERATION
Channel 1 operational, connect an HB LED string* to VOUT and OUT1.
Channel 1 OUT1 not used.
Channel 2 operational, connect an HB LED string* to VOUT and OUT2.
Channel 2 OUT2 not used.
Channel 3 operational, connect an HB LED string* to VOUT and OUT3.
Channel 3 OUT3 not used.
Channel 4 operational, connect an HB LED string* to VOUT and OUT4.
Channel 4 OUT4 not used.
*The
series-connected HB LED string must be rated no less than 150mA.
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