Maxim Integrated MAX16841 Evaluation Kit MAX16841EVKIT# MAX16841EVKIT# Data Sheet

SUPPLIER

PHONE

WEBSITE

Bel Fuse Inc.

201-432-0463

www.belfuse.com

Central Semiconductor Corp.

631-435-1110

Coilcraft, Inc.

847-639-6400

Diodes Incorporated

805-446-4800

www.diodes.com

Fairchild Semiconductor

888-522-5372

770-436-1300

www.murata-northamerica.com

ON Semiconductor

602-244-6600

www.onsemi.com

Panasonic Corp.

800-344-2112

Rubycon Corp.

408-467-3864

www.rubycon.com

Susumu International USA

208-328-0307

TDK Corp.

847-803-6100

Vishay

402-563-6866

www.vishay.com

Würth Electronik GmbH & Co. KG

201-785-8800

 _________________________________________________________________  Maxim Integrated Products  3

MAX16841 Evaluation Kit

Evaluates: MAX16841

•  MAX16841 EV kit
•  85V to 264V AC source
•  6 to 8 series-connected LED strings rated no less than

500mA

•  Current  probe  to  measure  the  LED  current  (the  LED

should be illuminated)

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)  Connect the AC source to the AC1 and AC2 test points.
2) Connect the LED string anode and cathode to the 

LED+ and LED- test points, respectively.

3) Clip the current probe across the LED+ wire to 

 

measure the LED current.

4)  Enable the power supply.
5)  Measure the LED current using the current probe.

The MAX16841 EV kit demonstrates the MAX16841 LED 

driver IC. The device is an average current-mode- control 

HB LED driver IC for buck and flyback topologies in offline 

LED lamp applications. The IC uses a proprietary input 

current-control scheme to achieve power-factor correc-

tion. The IC’s LED driver uses constant-frequency, aver-

age current-mode control to control the duty cycle of the 

external switching MOSFET (N1). The IC is available in an 

8-pin SO package.
The EV kit circuit is configured in a flyback topology 

and provides up to 10W of output power for a string of 8 

series LEDs connected at the LED+ and LED- test points. 

The converter switching frequency is set at 70kHz. The 

EV kit circuit operates from an AC supply voltage of 

90V

RMS

 to 265V

RMS

. The EV kit is designed on a proven 

2oz copper, two-layer small PCB footprint design. The EV 

kit is optimized for operation in the 180V

RMS

 to 265V

RMS 

range.
The IC uses average current-mode control, with the 

circuit configured such that the average current flowing 

into the current-sense resistor (R1) on a cycle-by-cycle 

(switching frequency) basis is set by the voltage on 

the REFI pin. The average current per switching cycle  

flowing into R1 is as follows:

REFI

av

V

- 0.1V

I

5 R1

=

×

where V

REFI

 is in volts, R1 is in ohms, and I

av

 is in amps.

Circuit components L1, L2, L3, and C1 provide EMI 

filtering. During the turn-on instant of the triac dimmer, 

there would be significant ringing due to high inrush 

current to charge the input capacitor, C3. The ringing 

can cause the line current to fall to zero and turn off 

the dimmer. Components R2, R6, and C4 function as a 

damper and help to limit the inrush current and ringing. 

Resistor R2 is bypassed by Q1 after approximately 55Fs 

of dimming instant, thereby reducing power dissipation 

in R2 and improving efficiency. Diode D4 provides fast 

discharge of C2 during off instant of the dimmer.