MIC2299-15YML Evaluation Board User Guide

MIC2299 Evaluation Board
3.5A ISWMIN, 2MHz, High Power LED
Driver w/ 3 Preset LED Current Settings
General Description
This board enables the evaluation of the 3.5A switch, High
Power white LED driver MIC2299. The board includes
components necessary to set the LED current to 20%,
50% and 100% of the nominal LED current (1A). The
external inputs also allow this to be programmed either
with additional resistors or voltages on the DIM or BRT
pins. A load disconnect switch prevents leakage and
protects the battery against short circuits while in
shutdown mode.
The evaluation board includes a push button switch which
sends a one shot pulse of 300ms to the enable pin to
prevent overheating when testing high power LEDs. Also
the enable pin can be driven to force the part into low Iq
mode.
The MIC2299, 2 MHz, Integrated Step-Up current
regulator, allows the use of small and very few external
components to create a compact boosted supply up to
13.5V with a core component footprint of just 0.25in2
(1.61cm2). The evaluation board has been configured with
3 fixed current settings chosen using JP1 and all externally
programmable inputs are accessible via board pins.
Requirements
The MIC2299 evaluation board requires an input power
source that is able to deliver at least 5A over the desired
input voltage range. For the load, an electronic load (ELoad) capable of constant voltage testing is required or a
high power LED mounted on a fan cooled heat sink. Note
that stability measurements must be carried out on an LED
load as E-Loads do not have the same dynamic
characteristics of a high power LED.
Precautions
The evaluation board does not have reverse polarity
protection. Applying a negative voltage to the VIN (J1)
terminal may damage the device.
The load current is only regulated if connected between
VOUT and FB terminals, the GND terminal close to the
VOUT terminal is provided for voltage measurements only.
The MIC2299 has a maximum input voltage rating of 10V
therefore the supply voltage should never exceed this
value.
Getting Started
1. Connect the input supply to the input terminals.
Take note of the polarity to prevent damage. An
ammeter can be used in-line with the VIN terminal
to measure input current. The Input voltage should
be measured at the input terminals to account for
any drops in test leads and amp meter.
2. Ensuring the jumper JP1 is at the left position
(50% load), connect the load to the output
terminals: +VO connects to the positive E-Load
input or Anode of the test LEDs, FB connects to
the negative E-Load input or the Cathode of the
test LEDs.
A low impedance ammeter can be connected inline with the +VO terminal for current
measurements. The output voltage should be
measured between the evaluation board terminals
+VO and GND (to measure converter efficiency) or
+VO and FB (to measure the voltage of the LED
load).
3. Switch on the E-Load (if using), then the input
supply. Measurements can now be taken of
efficiency, switching waveform and output current
regulation. When testing 1A load (JP1 open),
ensure that these are pulse tests only to prevent
damage to the LED. LED manufacturers
recommend <10% duty cycle and 3s period.
Ordering Information
Part Number
Description
MIC2299-15YML EV
Evaluation Board with MIC2299YML
15V OVP Device
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2007
M9999-092707-A
Micrel, Inc.
MIC2299 Evaluation Board
The push button switch is set to give a nominal 300ms
pulse to the load to prevent damage to external LEDs. For
testing continuous loading at lower currents, this monostable can be bypassed by driving the EN terminal with a
voltage source above the enable threshold level.
The external pins can be driven to set any current between
the minimum and maximum values. See table. The
nominal current setting can be reduced by choosing a
larger value for R1 (current sense resistor). The 100%
current level can be set by using the following equation:
ILED100% = 0.2/R1
The values in the table will scale with the nominal 100%
current setting. So for example, if the 100% current is set
to 500mA, 0Ω on BRT will set LED current to 100mA,
50kΩ to 250mA etc.
Evaluation Board
DIM Voltage
Board Description
By default, the board is set to give 500mA nominal current
into 2 series connected Power LEDs (JP1 at pre-FLSH
position). If the load is not present, the over voltage
protection (OVP) will limit VOUT to prevent damage to
output devices. JP1 can be removed to set the load
current higher to 1A (Flash) or moved to pins 1-2 to set a
lower 200mA current (Torch). Care should be taken as
removing the jumper sets the maximum current of 1A.
0V to 200mV
LED Current
RBRT = Open
40mA to 1A
RBRT = GND
0 to 200mA
RBRT Voltage
LED Current
0V to 1V
200mA to 1A
RBRT Resistance
LED Current
0Ω to 100kΩ
200mA to 1A
Board Performance
High Power White LED Driver
Efficiency VLED = 9V
100
90
80
50
40
ILED - 0.4A
ILED - 0.2A
180
144
30
108
20
10
72
36
0
-10
70
-20
60
-30
-40
50
2.5 3 3.5 4 4.5 5 5.5 6 6.5
SUPPLY VOLTAGE (V)
-50
1
Efficiency
September 2007
Bode Plot 2.2µH
(1A LED Load)
-36
Gain (3VIN)
Gain (4.2VIN)
Phase (3VIN)
Phase (4.2VIN)
10
100
FREQUENCY (kHz)
-72
-108
-144
-180
1000
Stability 2.2µH Inductor
2
M9999-092707-A
Micrel, Inc.
MIC2299 Evaluation Board
1100
1000
900
800
700
600
500
400
300
200
100
0
0
LED Current
vs. DIM Voltage
1100
1000
900
800
700
600
500
400
300
200
100
0
0
40
80 120 160 200
DIM VOLTAGE (mV)
LED Current
vs. RBRT
VIN = 3.6V
20
40
60
80 100 120 140
LED Current Programming (VDIM)
LED Current Programming (RBRT)
Switching Waveforms (BRT – GND)
PWM Programming
250
LED Current
vs. DC (on EN Pin)
1200
LED Current
vs. DC (on BRT Pin)
1000
200
800
150
600
100
400
50
0
0
200
20
40
60
DC (%)
80
0
0
100
LED Current Programming
(100Hz PWM on Enable)
September 2007
5
10
15 20 25
DC (%)
30
35
LED Current Programming
(1kHz PWM on BRT)
3
M9999-092707-A
Micrel, Inc.
MIC2299 Evaluation Board
Schematic
September 2007
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Micrel, Inc.
MIC2299 Evaluation Board
Bill of Materials
Item
Part Number
Manufacturer
Description
Qty
2.2µF/10V, 0805 Ceramic Capacitor
1
Core Components
C1
C2
C3
C4
C5
L1
R1
C1608X5R1A225M
VJ0603Y104KXAAT
C1608C0G1H101J
C1608X5R1H333K
C2012X5R1C475K
TDK
(1)
(2)
Vishay
0.1µF/ 16V, 0603 Ceramic Capacitor
1
TDK
(1)
100pF/16V, 0603 Ceramic Capacitor
1
TDK
(1)
33nF/6.3V, 0603 Ceramic Capacitor
1
TDK
(1)
4.7µF/16V, 0805 Ceramic Capacitor
1
IHLP1616BZ11-2R2
Vishay(2)
2.2µH, 3.3A, 2mm Inductor
SD414-2R2
Coiltronics(3)
2.2µH, 2.8A, 1.4mm Inductor
L-0805M0R20FS
Vishay(2)
200mΩ, 0.2W, 0805 Metal film, 200mW Resistor
1
R2
CRCW0603620RFKTA
Q1
Si5857DU
U1
MIC2299YML
Item
Part Number
(2)
Vishay
Vishay(2)
Micrel
1
620Ω, 0603 Resistor
1
2A Schotty & P-Channel MOSFET, 1206 package
1
3.5A 2MHz, High Power LED Driver
1
Description
Qty
(4)
Manufacturer
Required for Evaluation Board Operation
C6
C7
TPSD107M016R0100
C1608JB1E105K
AVX(5)
TDK
(1)
(2)
Vishay
100µF/16V, Tantalum Capacitor
1
1µF/25V, 0603 Ceramic capacitor
1
C8
VJ0603Y104KXAAT
100nF/16V, 0603 Ceramic Capacitor
1
R3
CRCW060349K9RFKTA
Vishay(2)
49.9k, 0603 Resistor
1
R4
CRCW06031K0FKTA
Vishay(2)
1k, 0603 Resistor
1
(2)
R5
CRCW0603330KFKTA
Vishay
330k, 0603 Resistor
1
R6
CRCW0603100KFKTA
Vishay(2)
100k, 0603 Resistor
1
R7, R8,
R9
CRCW060310K0FKTA
Vishay(2)
10k, 0603 Resistor
3
Q2
2n7002
Vishay(2)
N-Channel MOSFET
1
SPNO Momentary Push Button
1
SOD323 signal diode
1
Header for Current Setting
1
SOT-23-5 Timer IC
1
S1
FES311161
Z1
BZX84-C12
JP1
3 pin Header
U2
MIC1555
Fujitsu
(6)
Infineon
(7)
Micrel(4)
Notes:
1. TDK: www.tdk.com
2. Vishay: www.vishay.com
3. Coiltronics: www.mouser.com/coiltronics
4. Micrel, Inc: www.micrel.com
5. AVX: www.avx.com
6. Fujitsu: www.fujitsu.com
7. Infineon: www.infineon.com
September 2007
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Micrel, Inc.
MIC2299 Evaluation Board
PCB Layout Recommendations
Top Layer
Bottom Layer
September 2007
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M9999-092707-A
Micrel, Inc.
MIC2299 Evaluation Board
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2007 Micrel, Incorporated.
September 2007
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M9999-092707-A