MAX1779EUE ,Low-Power Triple-Output TFT LCD DC-DC ConverterFeaturesThe MAX1779 triple-output DC-DC converter provides Three Integrated DC-DC Convertershighly ..
MAX1779EUE ,Low-Power Triple-Output TFT LCD DC-DC ConverterApplicationsTOP VIEWTFT Active-Matrix LCD DisplaysRDY 1 16 TGNDPassive-Matrix LCD DisplaysFB 2 15 L ..
MAX1779EUE+ ,Low-Power Triple-Output TFT LCD DC-DC ConverterFeaturesThe MAX1779 triple-output DC-DC converter provides♦ Three Integrated DC-DC Convertershighly ..
MAX1779EUE+ ,Low-Power Triple-Output TFT LCD DC-DC ConverterMAX177919-1795; Rev 1; 9/05Low-Power Triple-Output TFT LCD DC-DCConverter
MAX1779EUE+T ,Low-Power Triple-Output TFT LCD DC-DC ConverterApplicationsTOP VIEWTFT Active-Matrix LCD DisplaysRDY 1 16 TGNDPassive-Matrix LCD DisplaysFB 2 15 L ..
MAX1779EUE+T ,Low-Power Triple-Output TFT LCD DC-DC ConverterELECTRICAL CHARACTERISTICS(V = +3.0V, SHDN = IN, V = V = +10V, TGND = PGND = GND, C = 0.22µF, C = 2 ..
MAX4614ESD+T ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesMAX4614/MAX4615/MAX461619-1501; Rev 0; 7/99Low-Voltage, High-Speed, Quad, SPST CMOS Analog Switches
MAX4614EUD ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesApplicationsPART TEMP. RANGE PIN-PACKAGEBattery-Operated EquipmentMAX4614CUD 0°C to +70°C 14 TSSOPA ..
MAX4614EUD ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesMAX4614/MAX4615/MAX461619-1501; Rev 0; 7/99Low-Voltage, High-Speed, Quad, SPST CMOS Analog Switches
MAX4614EUD+ ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesApplicationsPART TEMP. RANGE PIN-PACKAGEBattery-Operated EquipmentMAX4614CUD 0°C to +70°C 14 TSSOPA ..
MAX4614EUD+ ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesFeaturesThe MAX4614/MAX4615/MAX4616 quad, low-voltage,♦ Fast Switching Times high-speed, single-pol ..
MAX4614EUD+T ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesGeneral Description ________
MAX1779EUE
Low-Power Triple-Output TFT LCD DC-DC Converter
General DescriptionThe MAX1779 triple-output DC-DC converter provides
highly efficient regulated voltages required by small
active matrix, thin-film transistor (TFT) liquid-crystal dis-
plays (LCDs). One high-power DC-DC converter and
two low-power charge pumps convert the +2.7V to
+5.5V input supply voltage into three independent out-
put voltages.
The primary high-power DC-DC converter generates a
boosted output voltage (VMAIN) up to 13V that is regu-
lated within ±1%. The low-power BiCMOS control cir-
cuitry and the low on-resistance (1Ω) of the integrated
power MOSFET allows efficiency up to 91%. The
250kHz current-mode pulse-width modulation(PWM)
architecture provides fast transient response and
allows the use of ultra-small inductors and ceramic
capacitors.
The dual charge pumps independently regulate one
positive output (VPOS) and one negative output (VNEG).
These low-power outputs use external diode and
capacitor stages (as many stages as required) to regu-
late output voltages up to +40V and down to -40V. A
proprietary regulation algorithm minimizes output rip-
ple, as well as capacitor sizes for both charge pumps.
The MAX1779 is available in the ultra-thin TSSOP pack-
age (1.1mm max height).
________________________ApplicationsTFT Active-Matrix LCD Displays
Passive-Matrix LCD Displays
PDAs
Digital-Still Cameras
Camcorders
FeaturesThree Integrated DC-DC Converters250kHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
±1% Accuracy
High Efficiency (91%)Dual Charge-Pump Outputs
Up to +40V Positive Charge-Pump Output
Down to -40V Negative Charge-Pump OutputInternal Supply SequencingInternal Power MOSFETs+2.7V to +5.5V Input Supply0.1µA Shutdown Current0.5mA Quiescent CurrentInternal Soft-StartPower-Ready OutputUltra-Small External ComponentsThin TSSOP Package (1.1mm max)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Pin Configuration19-1795; Rev 0; 11/00
Ordering Information
Typical Operating Circuit appears at end of data sheet.
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICSStresses 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, SHDN, TGND to GND.........................................-0.3V to +6V
DRVN to GND.........................................-0.3V to (VSUPN+ 0.3V)
DRVP to GND..........................................-0.3V to (VSUPP+ 0.3V)
PGND to GND.....................................................................±0.3VRDYto GND...........................................................-0.3V to +14V
LX, SUPP, SUPN to PGND.....................................-0.3V to +14V
INTG, REF, FB, FBN, FBP to GND...............-0.3V to (VIN+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
16-Pin TSSOP (derate 9.4mW/°C above +70°C)..........755mW
Operating Temperature Range
MAX1779EUE..................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
ELECTRICAL CHARACTERISTICS (continued)(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA
= 0°C to +85°C,
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
ELECTRICAL CHARACTERISTICS
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA
= -40°C to +85°C,
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Typical Operating Characteristics
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA= -40°C to +85°C,
Note 1:Specifications to -40°C are guaranteed by design, not production tested.
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Detailed Description
The MAX1779 is a highly efficient triple-output power
supply for TFT LCD applications. The device contains
one high-power step-up converter and two low-power
charge pumps. The primary boost converter uses an
internal N-channel MOSFET to provide maximum effi-
ciency and to minimize the number of external compo-
nents. The output voltage of the main boost converter
(VMAIN) can be set from VINto 13V with external resistors.
The dual charge pumps independently regulate a posi-
tive output (VPOS) and a negative output (VNEG). These
low-power outputs use external diode and capacitor
stages (as many stages as required) to regulate output
voltages up to +40V and down to -40V. A proprietary
regulation algorithm minimizes output ripple as well as
capacitor sizes for both charge pumps.
Also included in the MAX1779 are a precision 1.25V
reference that sources up to 50µA, logic shutdown,
soft-start, power-up sequencing, fault detection, and an
active-low open-drain ready output.
Main Boost Converter
The MAX1779 main step-up converter switches at a
constant 250kHz internal oscillator frequency to allow
the use of small inductors and output capacitors. The
MOSFET switch pulse width is modulated to control the
power transferred on each switching cycle and to regu-
late the output voltage.
During PWM operation, the internal clock’s rising edge
sets a flip-flop, which turns on the N-channel MOSFET
(Figure 1). The switch turns off when the voltage-error,
slope-compensation, and current-feedback signals trip
the comparators and reset the flip-flop. The switch
remains off for the rest of the clock cycle. Changes in
the output voltage error signal shift the switch current
trip level, consequently modulating the MOSFET duty
cycle.
Dual Charge-Pump Regulator
The MAX1779 contains two individual low-power charge
pumps. One charge pump inverts the supply voltage
(SUPN) and provides a regulated negative output voltage.
The second charge pump doubles the supply voltage
(SUPP) and provides a regulated positive output voltage.
The MAX1779 contains internal P-channel and N-channel
MOSFETs to control the power transfer. The internal
MOSFETs switch at a constant 125kHz (0.5 ✕fOSC).
Negative Charge Pump
During the first half-cycle, the P-channel MOSFET turns
on and the flying capacitor C5 charges to VSUPNminus
a diode drop (Figure 2). During the second half-cycle,
the P-channel MOSFET turns off, and the N-channel
MOSFET turns on, level shifting C5. This connects C5 in
parallel with the reservoir capacitor C6. If the voltage
across C6 minus a diode drop is lower than the voltage
across C5, charge flows from C5 to C6 until the diode
(D5) turns off. The amount of charge transferred to the
output is controlled by the variable N-channel on-resis-
tance.
Positive Charge Pump
During the first half-cycle, the N-channel MOSFET turns
on and charges the flying capacitor C3 (Figure 3). This
initial charge is controlled by the variable N-channel
on-resistance. During the second half-cycle, the N-
channel MOSFET turns off and the P-channel MOSFET
turns on, level shifting C3 by VSUPPvolts. This connects
C3 in parallel with the reservoir capacitor C4. If the volt-
age across C4 plus a diode drop (VPOS+ VDIODE) is
smaller than the level-shifted flying capacitor voltage
