EVB10801 Datasheet DownloadLink 4719

Evaluation board EVB10801
Power LED driver for automotive applications
1.
Scope
This document describes the design and use of the MLX10801 evaluation board. For a general description about
the functionality of the MLX10801 please refer to the MLX10801 data sheet. Please consult the MLX10801 internet
product page at http://www.melexis.com for the latest updates.
2.
Applications
The MLX10801 evaluation board is intended to be used as an application example of the MLX10801 Power LED
driver. It was developed to demonstrate the features of the circuit and is suitable to be used in prototypes and
mock ups to allow quick implementation of the MLX10801 in a LED lighting application.
3.
Other Components Needed
LED(s): - all High Brightness LEDs up to 1W, e.g.:
Application Circuit
Panasonic
FK series
4.
Lumileds Luxeon®
Cree XLamp™ 7090 series
OSRAM (Advanced) Power TOPLED® ,OSRAM Golden Dragon®
Nichia POWER LED Series
Figure 1: Evaluation board schematic
390121080102 Rev. 004
Author: SSZ
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Evaluation board EVB10801
Power LED driver for automotive applications
5.
Connector Pin Definitions
Connector J1 (Supply)
Pin1
Pin2
Pin3
Pin4
Connector J2 (Program)
Pin1
Pin2
Pin3
Pin4
Pin5
Pin6
Connector J3 (LED)
Pin1
Pin2
Pin3
Signal
CNTR
N.C.
VBAT
GND
Signal
VS
GND
CALIB
N.C.
RSENS
DSENS
Signal
LEDGND
LED+
Connection
Control Pin for PWM and sleep mode
not connected, can be used as polarisation pin
Supply voltage 6..28V DC
Supply return
Connection
Supply voltage 6..28V DC, only in programming mode
Supply return, 0V
Communication for EEPROM programming
not connected, can be used as polarisation pin
Peak current Information
Forward bias voltage of temperature sensor
Connection
Cathode LED
Supply return, 0V, can be used for shielding
Anode LED
Note: signals in bold are compulsory
6.
PCB Layout
J1 Pinout (Supply)
Pin1
Pin2
Pin3
Pin4
J3 Pinout (LED)
CNTR
N.C.
VBAT
GND
Pin1
Pin2
Pin3
LEDGND
LED+
J2 Pinout (Program)
Pin1
Pin2
Pin3
Pin4
Pin5
Pin6
VS
GND
CALIB
N.C.
RSENS
DSENS
390121080102 Rev. 004
Author: SSZ
Figure 2: Evaluation board dimensions and locations
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Evaluation board EVB10801
Power LED driver for automotive applications
7.
Minimal Board Connections
For normal operation only the following connections are necessary. It is not recommended to use the
connector J2 (VS, Pin1) for supplying the board as there is no reverse polarity diode on that pin.
The LED is connected to the board via a polarised plug to avoid incorrect connection.
Figure 3: Minimal board connections
8.
Description
For details on the function of the LED driver circuit, please refer to the MLX10801 IC specification.
8.1.
General
Supply voltage (6..28V DC) is applied to J1, Pin3 while Pin4 is the corresponding GND connection. The LEDs have
to be connected to J3, anode to LED+ (Pin3), Cathode to LED- (Pin1). Pin2 (GND) can optionally be used to shield
LED signals if desired.
8.2.
Dimming via PWM
Dimming can be achieved via the digital input CNTR that is accessible via J1 (Pin1). The Jumper JMP2 must be
removed (it is set by default) for PWM dimming. Any TTL input signal with a frequency of 30Hz..4kHz can be used
as PWM input.
8.3.
Temperature Sensing
In order to avoid destruction of the IC and/or the LED due to overheating, a temperature shut off
was implemented. Generally there are two different modes for temperature sensing, internal
and external. For details please refer to the MLX10801 IC specification.
The evaluation board contains of a temperature sensor (diode BAS16) on-board. In case a direct temperature
sensing of the LED is desired, an external temperature sensor (Dext) can be placed close to the LED.
390121080102 Rev. 004
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Evaluation board EVB10801
Power LED driver for automotive applications
Virtually any small signal switching diode with dUF/dT ≈ -2mV/K can be used for that. Connection for such a
temperature sensor is available on J2, Pin6. If used, the on-board temperature sensor D2 must be switched off.
This is achieved by removing Jumper JMP1 (set by default). The following schematic shows the connection of an
external temperature sensor:
Figure 4: External temperature sensor connections
8.4.
Programming the IC
Any programming of the circuit is accomplished via the calibration pin CALIB. It is accessible at connector J2,
Pin 3. A jumper that is set by default between CALIB and GND (to protect the CALIB pin from voltages that could
result in faulty programming) has to be removed before programming.
Supply (VS) and GND have to be applied at this connector too as shown below in figure 4. Only these
three wires are necessary for programming. For details about the calibration interface and procedure please refer
to the MLX10801 IC specification.
Note: Do not use VBAT at connector J1 (Pin3) to supply the board in programming mode! Due to the
additional voltage drop caused by the reverse polarity diode D1, the voltage levels of the multilevel CALIB
interface may shift in a way that proper programming can not be guaranteed anymore (however it will
function properly in most cases).
Figure 5: Programming interface
390121080102 Rev. 004
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Evaluation board EVB10801
Power LED driver for automotive applications
8.4.1. Evaluation board and Fileloader FL10801
The FL10801 output connector consists of all necessary lines VS, GND and CALIB. They have to be connected to
their respective counterparts on the evaluation board. In that case, the evaluation board is completely driven by the
supply of the FL10801. No additional supply for the evaluation board is necessary.
If a LED is connected to the evaluation board, the result of a programming cycle can directly be observed without
the need of disconnecting it from the FL10801.
For details about the FL10801 and its software please refer to the FL10801 description.
9.
Used Components
Board Part
Number
D1
Type
Category
Alternative Part(s)
(Manufacturer)
many
Data Sheet Download
Fast
Recovery
Part Name
(Manufacturer)
RS1D
(GS,FCH)
Rectifier
D2
Diode
Switching
Diode
BAS16
(PHI)
many
www.semiconductors.philips.com
D3
Rectifier
Ultrafast
Recovery
ES1D
(GS,FCH)
L1
Inductor
WE-PD220µH
(WE)
www.gensemi.com
www.semiconductors.philips.com
www.semiconductors.philips.com
www.wuerth-elektronik.de
www.panasonic.com/industrial
www.toko.com
www.coilcraft.com
C1
Capacitor Ceramics
100nF/50V X7R
B37941
(Epcos)
BYG22D (TFK)
BYG80D (PHI)
BYD 77D (PHI)
unshielded:
ELC08D221E (PS)
8RHB 220µH (TK)
shielded:
MSS1260224KXB (CC)
many
C2
not populated
C3
Capacitor
47µF/35V
Electrolytic EEEFK1V470P many, preferably
FK series (PS)
low ESR type
www.panasonic.com/industrial
C4
Capacitor
1µF/50V
Ceramics
Z5U
B37951
(Epcos)
many
www.epcos.com
R1
Resistor
47k
Standard
0805
D12CRCW
(Vishay)
many
www.vishay.com
R2
Resistor
0.47R/
0.25W
MiniMELF
type
MMA0204
(BC
components)
many
www.bccomponents.com
www.vishay.com
www.epcos.com
manufacturer codes:
GS= General Semiconductor FCH=Fairchild Semiconductor
PS=Panasonic
TFK=Vishay-Telefunken
CC=Coilcraft
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PHI= Philips Semiconductor
WE=Würth Elektronik
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Evaluation board EVB10801
Power LED driver for automotive applications
10.
Practical EMC results
The EVB10801 is designed for a good electromagnetic emission behaviour. Please refer to the MLX10801 IC
specification as well as to the available application notes for EMC considerations. The conducted electromagnetic
emission measurement (according to IEC 61967-4) was performed using the following setup for the EVB10801:
Components:
R2 = 0.47R
L1 = 220µH
Supply/Load:
Vbat =13,0V
LED: Luxeon LXHL-BWO I
MLX10801 Trimming:
Imax =
1 0 0 1 (=360mV)
tmon = 0 1 1 0 0 0 (=24µs)
- jitter enabled
This is equivalent to the following switching frequency:
fsw_9V =18kHz
fsw_13.8V =24kHz
fsw_16V =26kHz
Att 0 dB
dBµV
1 MHz
RBW
10 kHz
MT
1 ms
PREAMP OFF
10 MHz
LIMIT CHECK
100 MHz
1 GHz
PASS
80
SGL
1 PK
CLRWR
70
60
L1
50
PRN
40
30
20
10
0
-10
150 kHz
Date:
25.MAR.2003
1 GHz
12:04:35
Figure 6: Conducted electromagnetic emission
390121080102 Rev. 004
Author: SSZ
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Evaluation board EVB10801
Power LED driver for automotive applications
11.
Conclusion
The MLX10801 evaluation board was designed to provide an easy solution for demonstrating the use of high
brightness LEDs in many applications as well as demonstrate the use of the MLX10801 LED driver chip. It is
suitable to be driven under automotive supply conditions (12V board systems) and is optimised in terms of
electromagnetic emission behaviour to be able to fulfil automotive standards.
If good emission behaviour is not an issue (e.g. industrial/consumer applications), smaller caps (for C3/C4) as well
as an unshielded coil can be used. Thus, size and cost can be reduced once more.
For the latest version of this document, go to our website at:
www.melexis.com
Or for additional information contact Melexis Direct:
Europe and Japan:
Phone: +32 13 61 16 31
E-mail: [email protected]
All other locations:
Phone: +1 603 223 2362
E-mail: [email protected]
QS9000, VDA6.1 and ISO14001 Certified
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