19-4951; Rev 1; 11/09
TION KIT
EVALUA BLE
AVAILA
Step-Up, Step-Down Regulator, Gate-On Charge Pump,
and Boost-Buck Regulator for TV TFT LCD Display
General Description
The MAX17122 multiple-output power-supply IC gener-
ates all the supply rails for thin-film transistor (TFT) liquid-
crystal display (LCD) TV panels. It can operate from 8V
to 16.5V input voltages and is optimized for LCD TV
panel applications running directly from 12V regulated
supplies. It includes a 22V internal-switch step-down
regulator for digital logic, a 22V internal switch step-
up regulator to power the TFT source drivers, and a
temperature-compensated 36V internal-switch boost-
buck regulator that produces a negative output that can
vary according to the temperature sensed by an exter-
nal NTC thermistor. All three of these regulators feature
high-efficiency and fixed-frequency operation. High-
frequency operation allows the use of small inductors
and capacitors, resulting in a compact solution.
The MAX17122 includes a positive charge-pump linear
regulator controller that uses an external pnp bipolar
junction transistor (BJT) to typically form a regulated
charge-pump doubler to supply the LCD positive gate-
driver supply voltage. A negative gate-driver supply is
derived linearly between the boost-buck regulator’s out-
put and ground, using an external npn BJT connected to
ground and a small bypass capacitor.
Other features include an external-capacitor-timed,
open-drain, power-good output that monitors the step-
down regulator’s feedback and a simple untimed output
that monitors the positive charge-pump linear regulator’s
feedback. A high-voltage stress function is available for
the step-up regulator output. The GATE output directly
drives an external p-channel MOSFET to provide True
ShutdownK of the step-up output.
The MAX17122 is available in a 6mm x 6mm, 40-pin thin
QFN lead-free package and operates over the -40NC to
+85NC temperature range.
Features
S
8V to 16.5V Operating Range
S
750kHz Switching Frequency
S
22V Internal-Switch High-Performance Step-Up
Regulator
Fast Load-Transient Response
Current-Mode PWM Operation
100mI, 3.9A nMOS Switch
Capacitor-Adjustable Soft-Start
High-Voltage Stress Function
Drives External pMOS Shutdown Switch
S
22V Internal-Switch Step-Down Regulator
Preset 1% Accurate 3.3V Output Voltage or
Adjustable Output (Dual Mode™)
Current-Mode PWM Operation
200mI, 2.5A nMOS Switch
Capacitor-Adjustable Power-Good Output
S
36V Internal-Switch Boost-Buck Regulator
Temperature-Compensated Output
Programmable Fixed Levels with Temperature-
Controlled Transition
Current-Mode PWM Operation
200mI, 1.8A pMOS Switch
S
Positive Charge-Pump Linear Regulator Controller
Adjustable 1% Accurate Output Voltage
Uses External pnp Transistor
Regulates Switching-Node-Driven Charge-
Pump Doubler
Power-Good Output
S
Negative Linear Regulator Controller
Adjustable 1.5% Accurate Output Voltage
Uses External npn Transistor
S
Soft-Start for All Outputs
S
Adjustable Power-Up Sequence
S
Timed-Output Fault Protection with Restart for All
Outputs
S
Latched Thermal-Shutdown Protection
S
40-Pin, 6mm x 6mm Thin QFN Package
MAX17122
Applications
LCD TV Panels
Ordering Information
PART
MAX17122ETL+
TEMP RANGE
-40NC to +85NC
PIN-PACKAGE
40 TQFN-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
True Shutdown and Dual Mode are trademarks of Maxim
Integrated Products, Inc.
Pin Configuration appears at end of data sheet.
_______________________________________________________________
Maxim Integrated Products
1
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.
Step-Up, Step-Down Regulator, Gate-On Charge Pump,
and Boost-Buck Regulator for TV TFT LCD Display
MAX17122
ABSOLUTE MAXIMUM RATINGS
IN, IN2, IN3, EN1, EN2, LX1, GATE,
DRVP, RHVS to AGND ......................................-0.3V to +22V
GATE to IN ...........................................................-6.5V to +0.3V
GND1 to AGND .................................................................
Q0.3V
DLY1, DLY2, DEL, VL, RESET, GPGD,
HVS to AGND ......................................................-0.3V to +6V
FBP, FBN, FB1, FB2, FB3, COMP1, COMP3, OUTB
SET, NTC, SS to AGND ......................... -0.3V to (V
VL
+ 0.3V)
DRVN to VL ...........................................................-36V to +0.3V
LX2 to GND1 ............................................ -0.3V to (V
IN2
+ 0.3V)
LX3 to IN3..............................................................-36V to +0.3V
BST2 to VL.............................................................-0.3V to +22V
BST2 to LX2.............................................................-0.3V to +6V
RMS LX1, GND1, IN2, IN3, LX3 Current (each pin) ............1.6A
RMS LX2 (total for both pins) ...............................................2.4A
RMS VL, DRVN, DRVP Current ..........................................50mA
Continuous Power Dissipation (T
A
= +70NC)
40-Pin Thin QFN
(derate 35.7mW/NC above +70NC) .........................2857.1mW
Operating Temperature Range .......................... -40NC to +85NC
Junction Temperature .....................................................+160NC
Storage Temperature Range............................ -65NC to +165NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
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.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
IN
= V
IN2
= V
IN3
= 12V,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25NC, unless otherwise noted.)
PARAMETER
GENERAL
IN, IN2, IN3
Input-Voltage Range
IN + IN2 + IN3
Quiescent Current
IN + IN2 + IN3
Shutdown Current
SMPS Operating Frequency
Phase Difference Between
Regulators
IN Undervoltage-Lockout
Threshold
VL REGULATOR
VL Output Voltage
VL Undervoltage-Lockout
Threshold
STEP-DOWN REGULATOR
OUTB Voltage in Fixed Mode
FB2 Voltage in Adjustable Mode
FB2 Adjustable-Mode
Threshold Voltage
FB2 = AGND, no load (Note 1)
V
OUTB
= 3.3V, no load (Note 1)
Dual-mode comparator
T
A
= +25NC
0NC < T
A
< +85NC
T
A
= +25NC
0NC < T
A
< +85NC
3.267
3.25
1.2375
1.23
0.10
0.15
1.250
3.300
3.333
3.35
1.2625
1.27
0.20
V
V
V
I
VL
= 10mA, V
FB1
= V
FB2
= V
FBP
= 1.1V, V
FBN
= 0.75V,
V
FB3
= 1.8V (all regulators switching)
VL rising, 2.5% hysteresis
4.9
3.6
5.0
4.0
5.1
4.4
V
V
Step-down and boost-buck
Step-down and step-up
V
IN
rising, 2.5% hysteresis
6
Only LX2 and LX3 switching (V
FB1
= V
FBP
= 1.5V, V
FB2
=
1.1V, V
FB3
= 1.8V, V
FBN
= 1.5V); V
EN1
= V
EN2
= 5V
LX2 and LX3 not switching (V
FB1
= V
FB2
= V
FBP
= 1.5V,
V
FBN
= 1.5V, V
FB3
= 0); V
EN1
= V
EN2
= 5V
EN1 = EN2 = AGND (shutdown)
638
8
10
2
0.55
750
180
180
7
8
16.5
15
mA
4
1
862
mA
kHz
Degrees
V
V
CONDITIONS
MIN
TYP
MAX
UNITS
2
______________________________________________________________________________________
Step-Up, Step-Down Regulator, Gate-On Charge Pump,
and Boost-Buck Regulator for TV TFT LCD Display
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
IN2
= V
IN3
= 12V,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25NC, unless otherwise noted.)
PARAMETER
Output Voltage Adjust Range
FB2 Fault-Trip Level
FB2 Input-Bias Current
DC Load Regulation
DC Line Regulation
LX2-to-IN2 nMOS Switch
On-Resistance
LX2-to-GND1 nMOS Switch
On-Resistance
BST2-to-VL pMOS Switch
On-Resistance
Low-Frequency Operation
OUTB Threshold
Low-Frequency Operation
Switching Frequency
LX2 Positive Current Limit
Soft-Start Ramp Time
Maximum Duty Factor
BOOST-BUCK REGULATOR
FB3 Regulation Voltage
FB3 Input-Bias Current
FB3 Pulldown Resistance
FB3 Fault-Trip Level
DC Load Regulation
DC Line Regulation
LX3-to-IN3 pMOS Switch
On-Resistance
LX3 Positive Current Limit
Soft-Start Ramp Time
Maximum Duty Factor
NTC, SET Current
NTC, SET Effective Voltage
Range
0NC < T
A
< +25NC
+25NC < T
A
< +85NC
0NC < T
A
< +25NC
+25NC < T
A
< +85NC
0.1
0.3
Duty cycle = 60%
Zero to full limit
85
98
1.8
No load, V
NTC
= 2V
V
FB3
= 0.5V
EN1 = AGND
Rising edge
0A < I
LOAD
< 400mA
No load, 10.8V < V
IN2
< 13.2V
T
A
= +25NC
0NC < T
A
< +85NC
1.63
1.62
-50
300
1.9
2.0
0.3
0.1
200
2.1
3
89
100
100
1.65
1.65
94
102
400
2.4
1.65
1.65
-125
1.67
1.68
-210
1200
2.1
V
nA
I
V
%
%/V
mI
A
ms
%
FA
V
Zero to full limit
68
2.5
LX2 only
6
6
Step-down output
Falling edge
V
FB2
= 1.5V
0.4A < I
LOAD
< 2A
No load, 10.8V < V
IN2
< 13.2V
CONDITIONS
MIN
1.5
0.96
50
1.0
125
0.5
0.1
200
10
12
0.8
188
3.0
3
75
82
3.5
400
24
24
TYP
MAX
3.6
1.04
200
UNITS
V
V
nA
%
%/V
mI
I
I
V
kHz
A
ms
%
MAX17122
3
_______________________________________________________________________________________
Step-Up, Step-Down Regulator, Gate-On Charge Pump,
and Boost-Buck Regulator for TV TFT LCD Display
MAX17122
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
IN2
= V
IN3
= 12V,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25NC, unless otherwise noted.)
PARAMETER
STEP-UP REGULATOR
Output-Voltage Range
Oscillator Maximum Duty Cycle
FB1 Regulation Voltage
FB1 Output Undervoltage
Fault Trip Level
FB1 Output Short Trip Level
FB1 Load Regulation
FB1 Line Regulation
FB1 Input-Bias Current
FB1 Transconductance
FB1 Voltage Gain
LX1 Bias Current
LX1 Current Limit
Current-Sense Transresistance
LX1 On-Resistance
SS Full Output Level
SS Charge Current
POSITIVE CHARGE-PUMP LINEAR REGULATOR (DRVP)
FBP Regulation Voltage
FBP Input-Bias Current
FBP Effective Load-Regulation
Error (Transconductance)
DRVP Sink Current
DRVP Off-Leakage Current
FBP Fault-Trip Level
Positive Regulator Soft-Start
Period
I
DRVP
= 1.35mA
V
FBP
= 1.25V
V
DRVP
= 15V, I
DRVP
= 0.6mA to 6mA
V
DRVP
= 15V, V
FBP
= 1.1V
V
DRVP
= 15V, V
FBP
= 1.5V
Falling edge
7-bit voltage ramp with filtering to prevent high peak
currents
T
A
= +25NC
0NC < T
A
< +85NC
0.985
0.98
-50
EN1 = AGND
Falling edge
V
DRVN
= -7.5V, I
DRVN
= 0.6mA to 6mA
V
DRVN
= -7.5V, V
FBN
= 0.85V
V
DRVN
= -7.5V, V
FBN
= 1.15V
10
40
250
0.45
0.5
23
0.96
10
0.1
1.0
3
T
A
= +25NC
0NC < T
A
< +85NC
1.2375
1.23
-50
15
1.250
1.2625
1.27
+50
30
30
10
1.04
V
nA
mV
mA
FA
V
ms
6
V
FB1
= COMP, C
COMP
= 1nF
Falling edge
Falling edge
0 < I
LOAD
< full, transient only
10.8V < V
IN
< 13.2V
V
FB1
= 2V
DI
=
Q2.5FA
at COMP, FB1 = COMP
FB1 to COMP
V
FB1
= 1.5V, V
LX1
= 20V
V
FB1
= 1.1V, duty cycle = 25%
3.9
0.16
10
150
T
A
= +25NC
0NC < T
A
< +85NC
V
IN
70
1.2375
1.23
0.96
0.35
1.0
0.375
-1
0.08
125
320
3500
10
4.5
0.23
100
1.25
9
12
40
5.1
0.3
200
0.15
200
560
76
1.250
20
83
1.2625
1.27
1.04
0.4
V
%
V
V
V
%
%/V
nA
FS
V/V
FA
A
V/A
mI
V
FA
CONDITIONS
MIN
TYP
MAX
UNITS
NEGATIVE LINEAR-REGULATOR CONTROLLER (DRVN)
FBN Regulation Voltage
FBN Input-Bias Current
FBN Pulldown Resistance
FBN Fault-Trip Level
FBN Effective Load-Regulation
Error (Transconductance)
DRVN Source Current
DRVN Off-Leakage Current
I
DRVN
= 1.35mA
1
1
1.015
1.02
+50
1000
0.55
46
V
nA
I
V
mV
mA
FA
4
______________________________________________________________________________________
Step-Up, Step-Down Regulator, Gate-On Charge Pump,
and Boost-Buck Regulator for TV TFT LCD Display
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
IN2
= V
IN3
= 12V,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25NC, unless otherwise noted.)
PARAMETER
POWER-GOOD BLOCKS
FB2 Power-Good Threshold
FB2 Threshold Hysteresis
RESET Output Low Voltage
RESET Leakage Current
FBP Power-Good Threshold
FBP Threshold Hysteresis
GPGD Output Low Voltage
GPGD Leakage Current
GATE FUNCTION
GATE Pulldown Current
GATE Drive Voltage
GATE Pullup Resistance
HVS BLOCK
HVS Input Low Voltage
HVS Input High Voltage
HVS Input Pulldown Resistance
RHVS Output Resistance
SEQUENCE CONTROL
EN1, EN2, DLY1, DLY2, DEL
Charge Current
EN1, EN2, DLY1, DLY2, DEL
Turn-On Threshold
EN1, EN2 Discharge Switch
On-Resistance
DLY1, DLY2, DLP Discharge
Switch On-Resistance
FAULT DETECTION
Duration to Trigger Fault
Duration to Restart After Fault
Thermal-Shutdown Threshold
Typical hysteresis = 15NC
50
160
+160
ms
ms
NC
VL < UVLO or fault tripped
EN1 = low or fault tripped
Measured at 1V
6
8.5
1.25
50
10
11
1.30
FA
V
I
I
I
RHVS
= 4mA
1.85
1
25
0.6
V
V
MI
I
GATE charging current
Gate done current
V
IN2
- V
GATE
, GATE enabled
GATE off, to IN2
5.0
0.15
0.62
5.35
25
5.65
mA
V
I
I
GPGD
= 1mA
V
GPGD
= 3V
I
RESET
= 1mA
V
RESET
= 3V
FBP rising
1.1
1.15
125
0.4
1
FB2 rising
0.975
1.00
12
0.4
1
1.2
1.025
V
mV
V
FA
V
mV
V
FA
CONDITIONS
MIN
TYP
MAX
UNITS
MAX17122
5
_______________________________________________________________________________________
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