Moteur de recherche de fiches techniques de composants électroniques
  French  ▼

Delete All
ON OFF
ALLDATASHEET.FR

X  

Preview PDF Download HTML

MAX1582 Fiches technique(PDF) 7 Page - Maxim Integrated Products

No de pièce MAX1582
Description  High-Efficiency, 26V Step-Up Converter for White LED Main and Subdisplay Backlighting
Download  10 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  MAXIM [Maxim Integrated Products]
Site Internet  https://www.maximintegrated.com/en.html
Logo MAXIM - Maxim Integrated Products

MAX1582 Fiches technique(HTML) 7 Page - Maxim Integrated Products

Back Button MAX1582 Datasheet HTML 2Page - Maxim Integrated Products MAX1582 Datasheet HTML 3Page - Maxim Integrated Products MAX1582 Datasheet HTML 4Page - Maxim Integrated Products MAX1582 Datasheet HTML 5Page - Maxim Integrated Products MAX1582 Datasheet HTML 6Page - Maxim Integrated Products MAX1582 Datasheet HTML 7Page - Maxim Integrated Products MAX1582 Datasheet HTML 8Page - Maxim Integrated Products MAX1582 Datasheet HTML 9Page - Maxim Integrated Products MAX1582 Datasheet HTML 10Page - Maxim Integrated Products  
Zoom Inzoom in Zoom Outzoom out
 7 / 10 page
background image
between the input and the LEDs through the inductor
and Schottky diode. To ensure the LEDs remain off
when the MAX1582 is in shutdown, the minimum input
forward voltage of the LED array must exceed the maxi-
mum input voltage. Typically, the leakage current
through the LEDs in shutdown is less than 1µA.
Soft-Start
The MAX1582 attains soft-start by charging CCOMP
gradually with a current source. When VCOMP rises
above 1.25V, the internal MOSFET begins switching,
but at a reduced duty cycle. When VCOMP rises above
2.25V, the duty cycle is at its maximum.
Overvoltage Protection
OVLO occurs when VOUT1 rises above 27V. The protec-
tion circuitry stops the internal MOSFET from switching
and causes VCOMP to decay to GND. The device
comes out of OVLO and into soft-start when VOUT1 falls
below 25V.
Design Procedure
Adjusting LED Current
Adjusting the MAX1582’s output current changes the
brightness of the LEDs. The LED current is set by the
voltage at CTRL (VCTRL) and the sense-resistor value
(RSENSE):
The VCTRL voltage range for adjusting output current is
0 to +1.62V. To set the maximum current, calculate
RSENSE when VCTRL is at its maximum as follows:
Power dissipation in RSENSE is typically less than 5mW;
therefore, a standard chip resistor is sufficient.
PWM Dimming Control
CTRL is also used as a digital input, allowing LED
brightness control with a logic-level PWM signal
applied directly to CTRL. The frequency range is from
200Hz to 200kHz, while 0% duty cycle corresponds to
zero current and 100% duty cycle corresponds to full
current. The error amplifier and compensation capaci-
tor form a lowpass filter, so PWM dimming results in DC
current to the LEDs without any additional RC filters
required.
Capacitor Selection
The exact values of input and output capacitors are not
critical. The typical value for the input capacitor is
2.2µF, and the typical value for the output capacitor is
0.1µF. Larger value capacitors can be used to reduce
input and output ripple, but at the expense of size and
higher cost.
CCOMP stabilizes the converter and controls soft-start.
Connect a 0.022µF capacitor from COMP to GND. The
minimum value for CCOMP is COUT / 10. The soft-start
time is found from:
Inductor Selection
Recommended inductor values range from 10µH to
47µH. A 22µH inductor optimizes the efficiency for most
applications, while maintaining a low 15mVP-P input rip-
ple. With input voltages near 5V, a larger value of induc-
tance may be more efficient. To prevent core saturation,
ensure that the inductor saturation current rating exceeds
the peak inductor current for the application. Calculate
the peak inductor current with the following formula:
Schottky Diode Selection
The MAX1582’s high switching frequency demands a
high-speed rectification diode (D1) for optimum
efficiency. A Schottky diode is recommended due to its
fast recovery time and low forward-voltage drop.
Ensure that the diode’s average and peak current
rating exceeds the average output current and peak
inductor current. In addition, the diode’s reverse break-
down voltage must exceed VOUT1. The RMS diode
current can be calculated from:
Applications Information
PC Board Layout
Due to fast-switching waveforms and high-current
paths, careful PC board layout is required. An evalua-
tion kit (MAX1582EVKIT) is available to speed design.
II
I
DIODE RMS
OUT
PEAK
()
≅×
1
I
VI
V
Vs
L
PEAK
OUT MAX
LED MAX
IN MIN
IN MIN
×
×
+
×µ
×
.
.
()
()
()
()
1
08
08
2
tC
V
A
SS
COMP
.
µ


125
5
R
I
SENSE
LED MAX
.
()
=
×
162
10
I
V
R
LED
CTRL
SENSE
=
×
10
High-Efficiency, 26V Step-Up Converter
for White LED Main and Subdisplay Backlighting
_______________________________________________________________________________________
7


Html Pages

1  2  3  4  5  6  7  8  9  10 


Fiches technique Télécharger

Go To PDF Page

Numéro de composants électroniques

No de pièceDescriptionHtml ViewFabricant
MAX1561 High-Efficiency 26V Step-Up Converters for Two to Six White LEDs 1  2  3  4  5  More Maxim Integrated Products
LM3500 Synchronous Step-up DC/DC Converter for White LED 1  2  3  4  5  More National Semiconductor (TI)
LM3557 Step-Up Converter for White LED Applications 1  2  3  4  5  More National Semiconductor (TI)
MAX1576 480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera Flash 1  2  3  4  5  More Maxim Integrated Products
LM3557 Step-Up Converter for White LED Applications 1  2  3  4  5  More National Semiconductor (TI)
TB62731FUG Step-up DC-DC Converter for White LED Driver 1  2  3  4  5  More Marktech Corporate
LM3502 Step-Up Converter for White LED Applications 1  2  3  4  5  More National Semiconductor (TI)
LM3501 Synchronous Step-up DC/DC Converter for White LED Applications 1  2  3  4  5  More National Semiconductor (TI)
AAT2806 Dual High Efficiency Charge Pump for White LED AND Flash Applications 1  2  3  4  5  More Advanced Analogic Technologies

Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn