MAX17127ETP+ Maxim Integrated Products, MAX17127ETP+ Datasheet

no-image

MAX17127ETP+

Manufacturer Part Number
MAX17127ETP+
Description
IC WLED DVR SIX STRING 20TQFN
Manufacturer
Maxim Integrated Products
Datasheet

Specifications of MAX17127ETP+

Topology
PWM, Step-Up (Boost)
Number Of Outputs
6
Internal Driver
Yes
Type - Primary
Automotive, Backlight
Type - Secondary
White LED
Frequency
250kHz ~ 1MHz
Voltage - Supply
5 V ~ 26 V
Mounting Type
Surface Mount
Package / Case
20-WFQFN Exposed Pad
Operating Temperature
-40°C ~ 85°C
Current - Output / Channel
30mA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Voltage - Output
-
Lead Free Status / Rohs Status
 Details
19-5164; Rev 0; 3/10
The MAX17127 is a high-efficiency driver for white light-
emitting diodes (LEDs). It is designed for large liquid-
crystal displays (LCDs) that employ an array of LEDs as
the light source. An internal switch current-mode step-up
converter drives the LED array, which can be configured
for up to six strings in parallel and 13 LEDs per string.
Each string is terminated with ballast that achieves Q2%
current-regulation accuracy, ensuring even LED bright-
ness. The MAX17127 has a wide input voltage range
from 5V to 26V, and provides adjustable 10mA to 30mA
full-scale LED current.
The MAX17127 can implement brightness control through
the PWM signal input, and LED current is directly con-
trolled by the external dimming signal’s frequency and
duty cycle.
The MAX17127 has multiple features to protect the con-
troller from fault conditions. Once an open/short string is
detected, the fault string is disabled while other strings
can still operate normally. The controller features cycle-
by-cycle current limit to provide constant operation and
soft-start capability. If the MAX17127 is in current-limit
condition, the step-up converter is latched off after an
internal timer expires. A thermal-shutdown circuit pro-
vides another level of protection. When thermal shut-
down happens, the MAX17127 is latched off.
The MAX17127’s step-up controller features an inter-
nal 0.12I (typ), 48V (max) power MOSFET with local
current-sense amplifier for accurate cycle-by-cycle cur-
rent limit. This architecture greatly simplifies the external
circuitry and saves PCB space. Low-feedback volt-
age at each LED string helps reduce power loss and
improve efficiency. The MAX17127 features resistor-
adjustable switching frequency from 250kHz to 1MHz,
which enables a wide variety of applications that can
trade off component size for operating frequency.
The MAX17127 is available in a thermally enhanced,
lead-free, 20-pin, 4mm x 4mm thin QFN package.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
_______________________________________________________________ Maxim Integrated Products 1
Six-String WLED Driver with Integrated
General Description
S
S
S
S
S
S
S
S
S
S
S
S
S
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Simplified Operating Circuit appears at end of data sheet.
MAX17127ETP+
5V to 26V Input Supply Voltage
Up to Six Parallel Strings Multiple Series-
Connected LEDs
250kHz to 1MHz Adjustable Switching Frequency
0.12I Internal HV Power MOSFET (48V max)
Low String Feedback Voltage: 480mV at 20mA
LED Current
Full-Scale LED Current Adjustable from 10mA to
30mA
Q2% Current-Regulation Accuracy Between
Strings
400ns Minimum String On-Time
100Hz to 25kHz PWM Input Range
Open and Short LED Protection
Output Overvoltage Protection
Thermal Shutdown
Small 20-Pin, 4mm x 4mm Thin QFN Package
PART
Notebook, Subnotebook, and Tablet Computer
Displays
Automotive Systems
Handy Terminals
Step-Up Converter
-40°C to +85°C
TEMP RANGE
Ordering Information
Applications
PIN-PACKAGE
20 TQFN-EP*
Features

Related parts for MAX17127ETP+

MAX17127ETP+ Summary of contents

Page 1

... Output Overvoltage Protection S Thermal Shutdown S Small 20-Pin, 4mm x 4mm Thin QFN Package S Ordering Information PART TEMP RANGE MAX17127ETP+ -40°C to +85°C +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Applications Notebook, Subnotebook, and Tablet Computer Displays Automotive Systems Handy Terminals Simplified Operating Circuit appears at end of data sheet. ...

Page 2

Six-String WLED Driver with Integrated Step-Up Converter ABSOLUTE MAXIMUM RATINGS V to AGND ........................................................-0.3V to +30V IN FB_ PGND .................................................-0.3V to +52V PGND to AGND ....................................................-0.3V to +0. PWM, EN, FPO, I.C. to AGND .....................-0.3V to ...

Page 3

Six-String WLED Driver with Integrated ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 12V COMP T = 0°C to +85°C, unless otherwise noted. Typical values are PARAMETER FPO OUTPUT FPO Off-Leakage Current Fault inactive, ...

Page 4

Six-String WLED Driver with Integrated Step-Up Converter ELECTRICAL CHARACTERISTICS (Circuit of Figure 12V COMP T = -40°C to +85°C, unless otherwise noted. Typical values are PARAMETER V Input Voltage Range IN MAX17127 ...

Page 5

Six-String WLED Driver with Integrated ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 12V COMP T = -40°C to +85°C, unless otherwise noted. Typical values are PARAMETER FB_ Minimum On-Time FAULT PROTECTION OVP Threshold ...

Page 6

Six-String WLED Driver with Integrated Step-Up Converter (Circuit of Figure 12V +25NC, unless otherwise noted LED CURRENT vs. BRIGHTNESS SETTING 200Hz PWM ...

Page 7

Six-String WLED Driver with Integrated (Circuit of Figure 12V +25NC, unless otherwise noted SWITCHING WAVEFORMS (V = 26V, BRIGHTNESS = 100 32V 120mA OUT OUT 1µs/div STARTUP WAVEFORMS ...

Page 8

Six-String WLED Driver with Integrated Step-Up Converter (Circuit of Figure 12V +25NC, unless otherwise noted LED-SHORT FAULT PROTECTION (BRIGHTNESS = 100%, 3 LEDs SHORT ON FB1) 10µs/div LINE-TRANSIENT RESPONSE (V = 21V 9V, ...

Page 9

Six-String WLED Driver with Integrated TOP VIEW COMP PWM PIN NAME 5V Linear Regulator Output DDIO a ceramic capacitor of 1FF or greater. Enable Pin high enables the MAX17127. An internal 200kI (typ) pulldown resistor ...

Page 10

Six-String WLED Driver with Integrated Step-Up Converter PIN NAME LED String 5 Cathode Connection. FB5 is the open-drain output of an internal regulator, which 7 FB5 controls current through FB5. FB5 can sink up to 30mA. If unused, connect FB5 ...

Page 11

Six-String WLED Driver with Integrated The MAX17127 typical operating circuit is shown as Figure 1. Table 1 lists some recommended components 26V C IN 4.7 µ 0.1 µ µ ...

Page 12

Six-String WLED Driver with Integrated Step-Up Converter Table 2. Component Suppliers SUPPLIER Murata Electronics North America, Inc. Nichia Corp. Sumida Corp. Toshiba America Electronic Components, Inc. Vishay V 5V LINEAR REGULATOR IN V DDIO FSLCT OSCILLATOR ERROR AMPLIFIER COMP Gm ...

Page 13

Six-String WLED Driver with Integrated Detailed Description The MAX17127 is a high-efficiency driver for arrays of white LEDs. It contains a fixed-frequency current-mode PWM step-up controller linear regulator, a dimming control circuit, an internal power MOSFET, and six ...

Page 14

Six-String WLED Driver with Integrated Step-Up Converter The MAX17127 can be placed into shutdown by pulling the EN pin low. When a critical failure is detected, the IC also enters shutdown mode. In shutdown mode, all functions of the IC ...

Page 15

Six-String WLED Driver with Integrated Overvoltage Protection To protect the step-up regulator when the load is open the output voltage becomes excessive for any rea- son, the MAX17127 features a dedicated overvoltage- feedback input (OVP). The OVP pin ...

Page 16

Six-String WLED Driver with Integrated Step-Up Converter Full-Scale and Low-Level LED Current The full-scale LED current is set by: × 20mA 180k I = LED_MAX R ISET The acceptable resistance range for ISET is 120kI < R < 360kI, which ...

Page 17

Six-String WLED Driver with Integrated The maximum output current in DCM is governed by the following equation × × f × η × LIM OUT_DCM(MAX × × V OUT OUT Inductor ...

Page 18

Six-String WLED Driver with Integrated Step-Up Converter Calculate the ripple current at that operating point and the peak current required for the inductor × V IN(MIN) OUT(MAX RIPPLE L V × OUT(MAX ...

Page 19

Six-String WLED Driver with Integrated The voltage rating and temperature characteristics of the output capacitor must also be considered. Rectifier Diode Selection The MAX17127’s high switching frequency demands a high-speed rectifier. Schottky diodes are recommended for most applications because of ...

Page 20

Six-String WLED Driver with Integrated Step-Up Converter FB Pin Maximum Voltage The current through each FB_ pin is controlled only during the step-up converter’s on-time. During the con- verter off-time, the current sources are turned off. The output voltage does ...

Page 21

Six-String WLED Driver with Integrated V ISET FSLCT I.C. EN PWM R_FPWM 3.3V FPO Chip Information PROCESS: BiCMOS ______________________________________________________________________________________ Simplified Operating Circuit (Direct-PWM Mode DDIO PGND OVP COMP AGND MAX17127 FB1 FB2 FB3 FB4 FB5 FB6 EP ...

Page 22

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 22 2010 Maxim Integrated Products © ...

Related keywords