E High Frequency Step Down Converter for Constant Current. Figure 1: Demonstration Board

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1 E. DEMSTRATI BOARD SEP, AN E. High Frequency Step Down Converter for Constant Current Figure : Demonstration Board What you get. Demo board with x step down converter for constant current with E. driving a RGB L with PWM from a microcontroller. Digitally isolated USB<->UART interface What you need in addition. An external Power supply for input voltage VS between U L +.V and.v Connectors. The connector C is for supply voltage VS and. The connector C is for connecting a USB<->UART interface. The connector C is for programming the microcontroller. The connector C is for connecting a V switching regulator instead using a. The connector R, GREEN and BLUE is for connecting a RGB Power L Start of Operation. Connect the RGB L to the connector R, GREEN and BLUE. Connect the input voltage to VS and. The RGB L starts to light and will change the colors.. The mean output current was set to ma for every color with the resistor R for the red L and with R for the green L and with R for the blue L. ELMOS Semiconductor AG Application Note QM-No.: ANE. /

2 E. DEMSTRATI BOARD SEP, AN The lower the resistance R+TR or R+TR or R+TR is, the higher is the output current. The minimum allowed resistance is kohm. With the following formula the output current can be calculated : I Lmean = I ocp, k t LXD(OFF ) (U L +U D ) L with I ocp,k = ma typically for R=k and TR=Ohm and t LXD(OFF) = ns typically and U D =.V typically The maximum peak current with R=k and TR=ohm is typically ma. The maximum peak current with R=k and TR=ohm is typically ma. Using the Command Interpreter Optionally a connection with a USB<->UART interface is possible. For this usage connect the USB<->UART interface to the E.x constant current demo. Connect with a pol Mini USB cable to USB of a PC. If a windows message like 'new hardware found' pops up, install the FT driver from the driver folder. An explanation for this driver installation can be found in the doc folder. Then start Hterm.exe from the Hterm folder. The default connection is Baud, N. Choose the right virtual COM Port and click connect. If typing a '?' in the bottom Hterm window, the possible commands will be send from the microcontroller and are displayed in the top of the Hterm window : > Press? for help >?? - Shows a summary of commands, all inputs DECIMAL! RGB <r><g><b> - Set direct PWM values for R L and GREEN L and BLUE L, stop colour/lightness change HSV <h><s><v> - Set hue H[..], saturation S[..], lightness V[..], stop colour/lightness change H <h> - Set H value, hue H [..9], stop colour/lightness change S <s> - Set S value, saturation S [..], stop colour/lightness change V <v> - Set V value, lightness V [..], stop colour/lightness change RUN <val> - Set speed of colour change, val=:hold colour, val=x:x*.s for full colour change HRUN <val> - Set speed of lightness change, val=:hold lightness, val=x:x*.s for full lightness change OFF - Set all PWM registers to => all Ls are off, stop colour/lightness change - Start with red in colour change mode, no lightness change STATUS - Shows the status of important values The software accepts commands for the HSV color space cylindrical coordinate representations of points in an RGB color model. For further details look for HSV color space in wikipedia.com. The command H will light the red L. The command H will light the green L, H will light the blue L. The command S <val> changes the saturation, the command V <val> changes the lightness. The command RUN changes the H parameter automatically, RUN stops the color change. The command HRUN changed the V parameter automatically, HRUN stops the lightness change. ELMOS Semiconductor AG Application Note QM-No.: ANE. /

3 E. DEMSTRATI BOARD SEP, AN Schematic C C uf ANSCHLUSSKLEMME POL C +.V TXDuC TXD RXDuC RXD SIP_UART C MISO_OCA Pin Pin SCK_OCB Pin MOSI Pin NRESET Pin Pin SIP R NRESET k C pf IC RESET Y.MHz XTAL XTAL C pf 9 AREF C nf A A C C nf nf 9 DIEPAD C D SIP ESD ATMEGA_QFN Pin Pin Pin IC -DPAK Vin Vout C nf SW RESET (ADC) PA (ADC) PA (ADC) PA (ADC) PA (ADC) PA (ADC) PA (ADC) PA (ADC) PA SCK_OCB (SCK) PB MISO_OCA (MISO) PB MOSI (MOSI) PB SW (SS) PB (AIN/OC) PB IROUT (AIN/INT) PB (T) PB (T/XCK) PB (TOSC) PC (TOSC) PC (TDI) PC L (TDO) PC SW (TMS) PC (TCK) PC (SDA) PC 9 (SCL) PC OC (OC) PD (ICP) PD OCA (OCA) PD OCB (OCB) PD (INT) PD (INT) PD TXDuC (TXD) PD 9 RXDuC (RXD) PD C nf IC TSOP Pin Pin Pin IROUT C9 R.u D R L L green k SW SW SWITCH-PB SW SW SWITCH-PB H H H H HOLE HOLE HOLE HOLE C C u u J C C u u J C9 C u u J C J nf OCB A E. TR A IC C J nf PGOOD A OCA E. TR A IC C J nf PGOOD A OC E. TR A µh (MSS-, MSS-, LPS-) IC L+ L D SS C uf PGOOD SENSE R k µh (MSS-, MSS-, LPS-) L+ L D SS C uf SENSE R k µh (MSS-, MSS-, LPS-) L+ L D SS C uf SENSE R k R Pin Pin PSS_G GREEN Pin Pin PSS_G BLUE Pin Pin PSS_G Figure : Demonstration Board Schematic Bill of Material Pos.-No. Unit/Description Ordering No. Distributor Comment Manufacturer R k, % P.KCCT-ND Digi-Key, /W Panasonic R k, % P.KCCT-ND Digi-Key, /W Panasonic R k, % P.KCCT-ND Digi-Key, /W Panasonic R k, % PKACT-ND Digi-Key, /W Panasonic R k, % P.KATR-ND Digi-Key, /W Panasonic TR, TR, TR k Trimmer ACP -L k Reichelt k Trimmer, % ACP C, C pf 99---ND Digi-Key, V, NPO Kemet C, C, C, C, C nf, % 9---ND Digi-Key, XR, V Murata C, C, C µf, -%.+.% Farnell, YV, V Multicomp C (optional) µf, ±%, V VF / K-D Reichelt,x,, ESR=mΩ Panasonic VFK L, L, L µh MSS-ML_ COILCRAFT Irms=.A,.mm x.mm COILCRAFT IC, IC, IC E. E. ELMOS SO with exposed die pad ELMOS IC ATMega ATMEGAA-MU-ND Digi-Key MCU AVR K FLASH MHZ Atmel ELMOS Semiconductor AG Application Note QM-No.: ANE. /

4 E. DEMSTRATI BOARD SEP, AN Pos.-No. Unit/Description Ordering No. Distributor Comment Manufacturer D, D, D, D SS SS-E/TGICT-ND Digi-Key Schottky, A, V, SMB Vishay D TOPL green ---ND Digi-Key ma green clr L OSRAM Y SMD Quarz C9,-HC9-SMD Reichelt SMD-Quarz, root,, MHz Auris C pin connector STLZ PTR PTR C pin strip SL xw, Reichelt pin UART connector C pin strip SL xw, Reichelt pin ISP connector C pin strip SL xw, Reichelt pin connector for V switching regulator PCB R, GREEN, BLUE print plug PSS /G Reichelt print plug, single plug, straight, pin Measurement Results The first measurements was made with L=LPS- and R=k and TR=Ohm with Bridgelux BXRA-W Power L (UL=9.V). Mean Output Current of. in Constant Current Mode.... Iout [A] Efficiency Factor of E. in Constant Current Mode 9. Efficiency Factor [%] ELMOS Semiconductor AG Application Note QM-No.: ANE. /

5 E. DEMSTRATI BOARD SEP, AN. Switching Frequency of E. in Constant Current Mode.. Frequency [khz] With Uin =V and Cout=.µF the ripple current of the L was measured to ±%. With Uin =V and Cout=µF the ripple current of the L was measured to ±9%. With Uin =V and Cout=.µF the ripple current of the L was measured to ±%. For lower output current choose E. (QFN) or E. (SO). For higher output current choose E. (QFN) or E. (SO). Usage restrictions ELMOS Semiconductor AG provide the E. Demonstration Board simply and solely for IC evaluation purposes in laboratory. The Kit or any part of the Kit must not be used for other purposes or within non laboratory environments. Especially the use or the integration in production systems, appliances or other installations is prohibited. Disclaimer ELMOS Semiconductor AG shall not be liable for any damages arising out of defects resulting from () delivered hardware or software, () non observance of instructions contained in this document, or () misuse, abuse, use under abnormal conditions or alteration by anyone other than ELMOS Semiconductor AG. To the extend permitted by law ELMOS Semiconductor AG hereby expressively disclaims and user expressively waives any and all warranties of merchantability and of fitness for a particular purpose, statutory warranty of non-infringement and any other warranty or product liability that may arise by reason of usage of trade, custom or course of dealing. ELMOS Semiconductor AG Headquarters Heinrich-Hertz-Str. Dortmund Germany Phone + 9 () Fax + 9 () sales@elmos.com Note ELMOS Semiconductor AG (below ELMOS) reserves the right to make changes to the product contained in this publication without notice. ELMOS assumes no responsibility for the use of any circuits described herein, conveys no licence under any patent or other right, and makes no representation that the circuits are free of patent infringement. While the information in this publication has been checked, no responsibility, however, is assumed for inaccuracies. ELMOS does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of a life-support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications. Copyright ELMOS Reproduction, in part or whole, without the prior written consent of ELMOS, is prohibited. /