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MAX1531
User Manual
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Rainbow Electronics MAX1531 User Manual

General Description
The MAX1530/MAX1531 multiple-output power-supply controllers generate all the supply rails for thin-film tran­sistor (TFT) liquid-crystal display (LCD) monitors. Both devices include a high-efficiency, fixed-frequency, step-down regulator. The low-cost, all N-channel, syn­chronous topology enables operation with efficiency as high as 93%. High-frequency operation allows the use of small inductors and capacitors, resulting in a com­pact solution. The MAX1530 includes three linear regu­lator controllers and the MAX1531 includes five linear regulator controllers for supplying logic and LCD bias voltages. A programmable startup sequence enables easy control of the regulators.
The MAX1530/MAX1531 include soft-start functions to limit inrush current during startup. An internal step­down converter current-limit function and a versatile overcurrent shutdown protect the power supplies against fault conditions. The MAX1530/MAX1531 use a current­mode control architecture, providing fast load transient response and easy compensation. An internal linear regulator provides MOSFET gate drive and can be used to power small external loads.
The MAX1530/MAX1531 can operate from inputs as high as 28V and are well suited for LCD monitor and TV applications running directly from AC/DC wall adapters. Both devices are available in a small (5mm x 5mm), ultra-thin (0.8mm), 32-pin QFN package and operate over the -40°C to +85°C temperature range.
Applications
LCD Monitors and TVs
Automotive LCDs
Features
♦ 4.5V to 28V Input Voltage Range ♦ 250kHz/500kHz Current-Mode Step-Down Converter
Small Inductor/Capacitors No Sense Resistor
♦ Three Positive Linear Regulator Controllers
One Positive and One Negative Additional Controller (MAX1531) Small Input and Output Capacitors
♦ Timed Reset Output ♦ Uncommitted Overcurrent Protection (MAX1531) ♦ Soft-Start for All Regulators ♦ Programmable Input Undervoltage Comparator ♦ Programmable Startup Sequencing
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for
LCD Monitors
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
RESET
V
IN
V
GON
25V
V
GOFF
-9V
V
IN
= 12V
ONL2
V
SOURCE
10V/500mA
V
GAMMA
9.7V
V
N
ONL5
ONL4
ONL3
SEQ
VL
RSTIN
V
OUT
3.3V/1.5A
V
LOGIC
2.5V/500mA
V
OUT
V
L
V
L
V
P
V
N
V
IN
V
IN
V
P
V
L
DRV3
FBL3
FBL1
DRV1
BST
IN
DH
LX
DL
PGND
FB
COMP
FBL2
DRV2
FBL5
DRV5
DRV4
FBL4
CSH
CSL
FREQ
ILIM
VL
EN
AGND
MAX1530
Minimal Operating Circuit
19-2866; Rev 0; 5/03
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Pin Configuration appears at end of data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX1530ETJ -40°C to +85°C 32 Thin QFN
MAX1531ETJ -40°C to +85°C 32 Thin QFN
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for LCD Monitors
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
IN, DRV1, DRV2, DRV3, DRV4, CSH,
CSL to AGND .....................................................-0.3V to +30V
DRV5 to VL .............................................................-28V to +0.3V
CSH to CSL ..............................................................-0.3V to +6V
VL to AGND ..............................................................-0.3V to +6V
PGND to AGND...................................................................±0.3V
LX to BST..................................................................-6V to +0.3V
BST to AGND..........................................................-0.3V to +36V
DH to LX .....................................................-0.3V to (BST + 0.3V)
DL to PGND ..................................................-0.3V to (VL + 0.3V)
SEQ, ONL2, ONL3, ONL4, ONL5, COMP,
ILIM to AGND............................................-0.3V to (VL + 0.3V)
RSTIN, RESET, EN, FB, FBL1, FBL2, FBL3, FBL4, FBL5,
FREQ to AGND.....................................................-0.3V to +6V
VL Short Circuit to AGND ...........................................Momentary
Continuous Power Dissipation (T
A
= +70°C)
32-Pin Thin QFN (derate 21.3mW/°C above +70°C) ...1702mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
GENERAL
PARAMETER CONDITIONS MIN TYP MAX UNITS
Operating Input Voltage Range (Note 1) 4.5 28.0 V Quiescent Supply Current V
FB
= V
FBL1
= V
FBL2
= V
IC Disable Supply Current EN = AGND 200 400 µA VL REGULATOR VL Output Voltage 5.5V < V
VL Undervoltage Lockout
Threshold
VL rising, 3% hysteresis 3.2 3.5 3.8 V
< 28V, 0 < IVL < 30mA 4.75 5 5.25 V
IN
CONTROL AND SEQUENCE SEQ, FREQ Input Logic High
Level
SEQ, FREQ Input Logic Low
Level
SEQ, FREQ Input Leakage
Current
2.0 V
0.6 V
-1 +1 µA
ONL_ Input Threshold ONL_ rising, 25mV hysteresis 1.201 1.238 1.275 V ONL_ Source Current SEQ = EN = VL, V
_ = 0 to 1.24V 1.8 2.0 2.2 µA
ONL
ONL_ Input Leakage Current SEQ = EN = VL, ONL_ = VL -500 +500 nA ONL_ Input Discharge Clamp
Resistance
SEQ = 0 800 1500 3000 Ω
EN Input Threshold EN rising, 5% hysteresis 1.201 1.238 1.275 V EN Input Leakage Current -50 +50 nA FAULT DETECTION
FB, FBL1, FBL2, FBL3, FBL4
Undervoltage Fault Trip Level
FBL5 Undervoltage Fault
Trip Level
FB, FBL1, FBL2, FBL3, FBL4 falling, 25mV hysteresis 1.081 1.114 1.147 V
FBL5 rising, 25mV hysteresis 300 400 500 mV
FBL3
= V
FBL4
= 1.5V, V
= 0 1.7 3.0 mA
FBL5
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for
LCD Monitors
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Dual Mode is a trademark of Maxim Integrated Products, Inc.
PARAMETER CONDITIONS MIN TYP MAX UNITS Comparator Bandwidth For EN, FB, FBL_ 10 kHz Duration to Trigger Fault Latch For FB, FBL_ 51 64 77 ms Overcurrent Protection Threshold (V Overcurrent Sense Common-
Mode Range
CSH Input Current V CSL Input Current V
Overcurrent Sense Filter RC Time
Constant
- V
) 270 300 330 mV
CSL
, V
CSL
= 2.7V to 28V 100 µA
= V
= 12V -50 +50 nA
CSH
2.7 28.0 V
V
CSH
CSH
CSH
CSL
50 µs
THERMAL PROTECTION Thermal Shutdown Temperature rising, 15°C hysteresis 160 °C RESET FUNCTION RSTIN Reset Trip Level RSTIN falling, 25mV hysteresis 1.081 1.114 1.147 V RSTIN Input Leakage Current V
= 1.5V -50 +50 nA
RSTIN
Comparator Bandwidth 10 kHz Reset Timeout Period 102 128 154 ms RESET Output Low Level I RESET Output High Leakage V
= -1mA 0.4 V
RESET
= 5V 1 µA
RESET
STEP-DOWN CONTROLLER ERROR AMPLIFIER FB Regulation Voltage 1.223 1.238 1.253 V
Transconductance FB to COMP 70 100 140 µS
Voltage Gain FB to COMP 200 V/V Minimum Duty Cycle 15 % FB Input Leakage Current V
= 1.5V -50 +50 nA
FB
FB Input Common-Mode Range (Note 2) -0.1 +1.5 V COMP Output Minimum Voltage V COMP Output Maximum Voltage V
Current-Sense Amplifier Voltage
Gain
Current-Limit Threshold
(Default Mode)
Current-Limit Threshold
(Adjustable Mode)
= 1.5V 1 V
FB
= 1.175V 3 V
FB
V
IN
- V
LX
2.75 3.5 4.0 V/V
PGND - LX, ILIM = VL 190 250 310 mV
PGND - LX, V
= 1.25V 190 250 310 mV
ILIM
ILIM Inp ut D ual M od e™ Thr eshol d 3.0 3.5 4.00 V OSCILLATOR
Switching Frequency
Maximum Duty Cycle
FREQ = AGND 200 250 300 FREQ = VL 425 500 575 FREQ = AGND 75 80 88 FREQ = VL 75 80 88
kHz
%
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for LCD Monitors
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER CONDITIONS MIN TYP MAX UNITS SOFT-START Step Size Measured at FB 1.238 / 32 V
Period
FET DRIVERS DH, DL On-Resistance 3 10 Ω DH, DL Output Drive Current Sourcing or sinking, V LX, BST Leakage Current V
POSITIVE LINEAR REGULATOR (LR1) FBL1 Regulation Voltage V FBL1 Input Bias Current V
FBL1 Effective Load Regulation
Error (Transconductance)
FBL1 Line Regulation Error I DRV1 Sink Current V DRV1 Off-Leakage Current V
FBL1 Input Common-Mode
Range
Soft-Start Step Size Measured at FBL1 1.238 / 32 V
Soft-Start Period
POSITIVE LINEAR REGULATORS (LR2 AND LR3) FBL_ Regulation Voltage V FBL_ Input Bias Current V
FBL_ Effective Load Regulation
Error (Transconductance)
FBL_ Line Regulation Error I DRV_ Sink Current V DRV_ Off-Leakage Current V
FBL_ Input Common-Mode
Range
Soft-Start Step Size Measured at FBL_ 1.238 / 32 V
FREQ = GND 1024 / f FREQ = VL 2048 / f
BST
= V
LX
or VDL = V
DH
= V
= 28V 20 µA
IN
/ 2 0.5 A
VL
OSC
OSC
LINEAR REGULATOR CONTROLLERS
= 5V, I
DRV1
= 1.5V -50 +50 nA
FBL1
V
= 5V, I
DRV1
= 100µA, 5.5V < VIN < 28V 5 mV
DRV1
= 1.175V, V
FBL1
= 1.5V, V
FBL1
= 100µA 1.226 1.245 1.264 V
DRV1
= 100µA to 2mA -1.5 -2 %
DRV1
= 5V 3 10 mA
DRV1
= 28V 0.1 10 µA
DRV1
(Note 2) -0.1 +1.5 V
FREQ = GND 1024 / f FREQ = VL 2048 / f
_ = 5V, I
DRV
_ = 1.5V -50 +50 nA
FBL
V
_ = 5V, I
DRV
_ = 100µA, 5.5V < VIN < 28V 5 mV
DRV
= 1.175V, V
FBL_
_ = 1.5V, V
FBL
_ = 100µA 1.226 1.245 1.264 V
DRV
_ = 50µA to 1mA -1.5 -2 %
DRV
= 5V 2 4 mA
DRV_
_ = 28V 0.1 10 µA
DRV
OSC
OSC
(Note 2) -0.1 +1.5 V
s
s
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for
LCD Monitors
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = -40°C to +85°C, unless otherwise noted.) (Note 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Soft-Start Period
POSITIVE LINEAR REGULATOR (LR4) FBL4 Regulation Voltage V FBL4 Input Bias Current V
FBL4 Effective Load Regulation
Error (Transconductance)
FBL4 Line Regulation Error I DRV4 Sink Current V DRV4_Off-Leakage Current V
FBL4 Input Common-Mode
Range
Soft-Start Step Size Measured at FBL4 1.238 / 32 V
Soft-Start Period
NEGATIVE LINEAR REGULATOR (LR5) FBL5 Regulation Voltage V FBL5 Input Bias Current V
FBL5 Effective Load Regulation
Error (Transconductance)
FBL5 Line Regulation Error I DRV5 Source Current V DRV5 Off-Leakage Current V
FBL5 Input Common-Mode
Range
Soft-Start Step Size Measured at FBL5 1.238 / 32 V
Soft-Start Period
FREQ = GND 1024 / f FREQ = VL 2048 / f
= 5V, I
DRV4
= 1.5V -50 +50 nA
FBL4
V
= 5V, I
DRV4
= 500µA, 5.5V < VIN < 28V 5 mV
DRV4
= 1.175V, V
FBL4
= 1.5V, V
FBL4
= 500µA 1.226 1.245 1.264 V
DRV4
= 500µA to 10mA -1.5 -2 %
DRV4
= 5V 10 28 mA
DRV4
= 28V 0.1 10 µA
DRV4
OSC
OSC
(Note 2) -0.1 +1.5 V
FREQ = GND 1024 / f FREQ = VL 2048 / f
= -10V, I
DRV5
= 0 -50 +50 nA
FBL5
V
= -10V, I
DRV5
= 100µA, 5.5V < VIN < 28V 5 mV
DRV5
= 200mV, V
FBL5
= 0, V
FBL5
DRV5
= 100µA 100 125 150 mV
DRV5
= 50µA to 1mA -1.5 -2 %
DRV5
= -10V 2 9 mA
DRV5
= -20V 0.1 10 µA
OSC
OSC
(Note 2) -0.1 +1.5 V
FREQ = AGND 1024 / f FREQ = VL 2048 / f
OSC
OSC
s
s
s
PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL Operating Input Voltage Range (Note 1) 4.5 28.0 V VL REGULATOR VL Output Voltage 5.5V < V
VL Undervoltage Lockout
Threshold
VL rising, 3% hysteresis 3.2 3.8 V
< 28V, 0 < IVL < 30mA 4.75 5.25 V
IN
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for LCD Monitors
6 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VIN= 12V, VEN= V
SEQ
= 5V, TA = -40°C to +85°C, unless otherwise noted.) (Note 3)
Note 1: Operating supply range is guaranteed by VL line regulation test for the range of 5.5V to 28V. Between 4.5V and 5.5V, the V
L
regulator might be in dropout; however, the part continues to operate properly.
Note 2: Guaranteed by design and not production tested. Note 3: Specifications to -40°C are guaranteed by design and not production tested.
PARAMETER CONDITIONS MIN TYP MAX UNITS
CONTROL AND SEQUENCE ONL_ Input Threshold ONL_ rising, 25mV hysteresis 1.201 1.275 V EN Input Threshold EN rising, 5% hysteresis 1.201 1.275 V FAULT DETECTION
FB, FBL1, FBL2, FBL3, FBL4
Fault Trip Level
FBL5 Fault Trip Level FBL5 rising, 25mV hysteresis 300 500 mV Overcurrent Protection Threshold (V RESET FUNCTION RSTIN Reset Trip Level RSTIN falling, 25mV hysteresis 1.081 1.147 V
ERROR AMPLIFIER FB Regulation Voltage 1.215 1.260 V
Current-Limit Threshold
(Default Mode)
Current-Limit Threshold
(Adjustable Mode)
POSITIVE LINEAR REGULATOR (LR1) FBL1 Regulation Voltage V FBL1 Input Bias Current V POSITIVE LINEAR REGULATORS (LR2 AND LR3) FBL_ Regulation Voltage V FBL_ Input Bias Current V POSITIVE LINEAR REGULATOR (LR4) FBL4 Regulation Voltage V FBL4 Input Bias Current V NEGATIVE LINEAR REGULATOR (LR5) FBL5 Regulation Voltage V FBL5 Input Bias Current V DRV5 Source Current V
FB, FBL1, FBL2, FBL3, FBL4 falling, 25mV hysteresis 1.081 1.147 V
- V
CSH
) 270 330 mV
CSL
STEP-DOWN CONTROLLER
PGND - LX, ILIM = VL 170 330 mV
PGND - LX, V
= 1.25V 170 330 mV
ILIM
LINEAR REGULATOR CONTROLLERS
= 5V, I
DRV1
= 1.5V
FBL1
_ = 5V, I
DRV
_ = 1.5V -50 +50 nA
FBL
= 5V, I
DRV4
= 1.5V -50 +50 nA
FBL4
= -10V, I
DRV5
= 0 -50 +50 nA
FBL5
= 200mV, V
FBL5
= 100µA 1.220 1.270 V
DRV1
-50 +50 nA
_ = 100µA 1.220 1.270 V
DRV
= 500µA 1.220 1.270 V
DRV4
= 100µA 100 150 mV
DRV5
= -10V 2 mA
DRV5
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for
LCD Monitors
_______________________________________________________________________________________ 7
Typical Operating Characteristics
(Circuit of Figure 1; including R5, R6, and D2; TA= +25°C, unless otherwise noted.)
STEP-DOWN EFFICIENCY vs. LOAD CURRENT
MAX1530 toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
1200900600300
60
70
80
90
100
50
0 1500
VIN = 12V
VIN = 20V
fSW = 500kHz
STEP-DOWN LOAD REGULATION
MAX1530 toc02
LOAD CURRENT (mA)
OUTPUT-VOLTAGE ERROR (%)
1200900600300
-0.12
-0.08
-0.04
0
-0.16 0 1500
SWITCHING FREQUENCY vs. LOAD CURRENT
FREQUENCY (kHz)
485
490
495
500
510
505
515
520
480
MAX1530 toc03
LOAD CURRENT (mA)
12009006003000 1500
STEP-DOWN REGULATOR LOAD TRANSIENT
MAX1530 toc04
40µs/div A: LOAD CURRENT, 1A/div B: OUTPUT VOLTAGE, 200mV/div, AC-COUPLED C: INDUCTOR CURRENT, 1A/div
A
0A
B
3.3V
0A
C
STEP-DOWN REGULATOR
SWITCHING WAVEFORM
MAX1530 toc05
2µs/div
A
B
C
A: LX, 10V/div B: OUTPUT VOLTAGE, 20 mV/div, AC-COUPLED C: INDUCTOR CURRENT, 1A/div
0V
3.3V
0A
STEP-DOWN REGULATOR
SOFT-START
MAX1530 toc06
1ms/div
A
C
A: EN, 2V/div B: OUTPUT VOLTAGE, 2V/div C: INDUCTOR CURRENT, 1A/div
0V
0V
B
0A
VL LOAD REGULATION
MAX1530 toc07
LOAD CURRENT (mA)
VL OUTPUT ERROR (%)
252015105
-0.4
-0.3
-0.2
-0.1
0
-0.5 030
STARTUP SEQUENCE
MAX1530 toc08
4ms/div
A: V
L
, 10V/div
B: V
OUT
, 5V/div
C: V
LOGIC
, 5V/div
D: V
SOURCE
, 20V/div
E: V
GAMMA
, 20V/div
F: V
GOFF
, 20V/div
G: V
GON
, 40V/div
A
B
C
D
E
F
G
LR1 BASE CURRENT
vs. DRV1 VOLTAGE
MAX1530 toc09
DRV1 VOLTAGE (V)
BASE CURRENT (mA)
8642
3
6
9
12
15
0
010
V
FBL1
= 1.175V
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for LCD Monitors
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 1; including R5, R6, and D2; TA= +25°C, unless otherwise noted.)
LR1 NORMALIZED LOAD REGULATION
0
LR1 NORMALIZED LINE REGULATION
0.2
LR1 LOAD TRANSIENT
MAX1530 toc12
-0.5
-1.0
VOLTAGE ERROR (%)
-1.5
-2.0 0 500
LOAD CURRENT (mA)
400300200100
MAX1530 toc10
OUTPUT-VOLTAGE ERROR (%)
LR2/LR3 BASE CURRENT
5
4
3
2
BASE CURRENT (mA)
1
0
vs. DRV2/DRV3 VOLTAGE
V
= V
FBL2
05
= 1.175V
FBL3
DRV2/DRV3 VOLTAGE (V)
MAX1530 toc13
VOLTAGE ERROR (%)
4321
0
-0.2
-0.4
-0.6
-0.8
-1.0 26
200mA LOAD CURRENT
543
INPUT VOLTAGE (V)
LR2 NORMALIZED LOAD REGULATION
0
-0.3
-0.6
-0.9
-1.2
-1.5 050
LOAD CURRENT (mA)
40302010
MAX1530 toc11
A: LR1 OUTPUT VOLTAGE, 100mV/div, AC-COUPLED B: LR1 LOAD CURRENT, 500mA/div
LR2 NORMALIZED LINE REGULATION
0.2
0
MAX1530 toc14
-0.2
-0.4
-0.6
OUTPUT-VOLTAGE ERROR (%)
-0.8
-1.0 925
INPUT VOLTAGE (V)
A
2.5V
B
0mA
40µs/div
MAX1530 toc15
20mA LOAD CURRENT
211713
LR3 NORMALIZED LOAD REGULATION
0
-0.5
-1.0
VOLTAGE ERROR (%)
-1.5
-2.0 020
LOAD CURRENT (mA)
161284
MAX1530 toc16
LR3 NORMALIZED LINE REGULATION
0.2
0
-0.2
-0.4
-0.6
OUTPUT-VOLTAGE ERROR (%)
-0.8
-1.0 24 40
20mA LOAD CURRENT
INPUT VOLTAGE (V)
vs. DRV VOLTAGE
30
V
= 1.175V
FBL4
25
MAX1530 toc17
20
15
10
BASE CURRENT (mA)
5
363228
0
010
DRV4 VOLTAGE (V)
LR4 BASE CURRENT
MAX1530 toc18
8642
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for
LCD Monitors
_______________________________________________________________________________________ 9
Typical Operating Characteristics (continued)
(Circuit of Figure 1; including R5, R6, and D2; TA= +25°C, unless otherwise noted.)
LR4 NORMALIZED LOAD REGULATION
MAX1530 toc19
LOAD CURRENT (mA)
VOLTAGE ERROR (%)
400300200100
-0.5
-0.4
-0.3
-0.2
-0.1
0
-0.6 0 500
LR4 NORMALIZED LINE REGULATION
MAX1530 toc20
INPUT VOLTAGE (V)
OUTPUT-VOLTAGE ERROR (%)
211713
-0.8
-0.6
-0.4
-0.2
0
0.2
-1.0 925
200mA LOAD CURRENT
LR4 LOAD TRANSIENT
MAX1530 toc21
40µs/div
A
B
A: LR4 OUTPUT VOLTAGE, 100mV/div, AC-COUPLED B: LR4 LOAD CURRENT, 500mA/div
10V
0mA
LR4 PULSED LOAD TRANSIENT
MAX1530 toc22
10µs/div
A
B
A: LR4 OUTPUT VOLTAGE, 100mV/div, AC-COUPLED B: LR4 LOAD CURRENT, 1A/div
10V
0A
MAX1531
OVERCURRENT PROTECTION (CSH, CSL)
MAX1530 toc23
20µs/div
A: V
LX
, 10V/div
B: V
OUT
, 5V/div
B
C
D
A
C: V
RESET
, 5V/div
D: V
CSH
- V
CSL
, 500mV/div
LR5 BASE CURRENT
vs. DRV5 VOLTAGE
MAX1530 toc24
DRV5 VOLTAGE (V)
BASE CURRENT (mA)
4321
2
4
6
8
10
0
05
V
FBL5
= 0V
MAX1530/MAX1531
Multiple-Output Power-Supply Controllers for LCD Monitors
10 ______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 1; including R5, R6, and D2; TA= +25°C, unless otherwise noted.)
Pin Description
LR5 NORMALIZED LOAD REGULATION
0
-0.2
-0.4
-0.6
VOLTAGE ERROR (%)
-0.8
-1.0 050
LOAD CURRENT (mA)
40302010
PIN
MAX1530 MAX1531
1 1 DRV2
2 2 FBL2
NAME FUNCTION
Gamma Linear Regulator (LR2) Base Drive. Open drain of an internal N-channel MOSFET. Connect DRV2 to the base of an external PNP pass transistor to form a positive linear regulator. (See the Pass Transistor Selection section.)
Gamma Linear Regulator (LR2) Feedback Input. FBL2 regulates at 1.245V nominal. Connect FBL2 to the center tap of a resistive voltage-divider between the LR2 output and AGND to set the output voltage. Place the divider close to the FBL2 pin.
MAX1530 toc25
LR5 NORMALIZED LINE REGULATION
1.0
20mA LOAD CURRENT
0.8
0.6
0.4
0.2
OUTPUT-VOLTAGE ERROR (%)
0
-0.2
-25 -9 INPUT VOLTAGE (V)
MAX1530 toc26
-13-17-21
Gate-On Linear Regulator (LR3) Feedback Input. FBL3 regulates at 1.245V nominal.
3 3 FBL3
4 4 DRV3
Connect FBL3 to the center tap of a resistive voltage-divider between the LR3 output and AGND to set the output voltage. Place the divider close to the FBL3 pin.
Gate-On Linear Regulator (LR3) Base Drive. Open drain of an internal N-channel MOSFET. Connect DRV3 to the base of an external PNP pass transistor to form a positive linear regulator. (See the Pass Transistor Selection section.)
5–10, 18, 19 — N. C. No Connection. Not internally connected.
Adjustable Reset Input. RESET asserts low when the monitored voltage is less than the reset trip threshold. RESET goes to a high-impedance state only after the monitored voltage remains above the reset trip threshold for the duration of the reset timeout period.
11 11 RSTIN
Connect RSTIN to the center tap of a resistive voltage-divider between the monitored output voltage and AGND to set the reset trip threshold. The internal RSTIN threshold of 90% of 1.238V allows direct connection of RSTIN to any of the device’s positive feedback pins.
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