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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

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MAX17116

Dual-Output DC/DC

Power Supply for AMOLED

General Description

The MAX17116 includes two current-mode 1.4MHz

switch mode power-supply (SMPS) regulators for active-

matrix organic light-emitting diode (AMOLED) displays.

The positive supply is provided by a step-up regulator

with a synchronous rectifier. The negative supply is

provided by an inverting regulator with a synchronous

rectifier.

The step-up DC-DC converter is a high-accuracy 250mA

regulator with an integrated power MOSFET switch

and synchronous rectifier. The synchronous rectifier

improves efficiency and also provides True Shutdown

Its 4.6V (fixed) output efficiency exceeds 85% at 150mA

from a 3.7V input. A built-in, 7-bit, digital soft-start func-

tion controls startup inrush currents.

The inverting DC-DC converter is a high-accuracy

250mA regulator with a built-in power MOSFET switch

and synchronous rectifier. Its -5.4V to -1.5V output effi-

ciency exceeds 80% at 150mA from a 3.7V input. A built-

in, 7-bit, digital soft-start function controls startup inrush

currents. The internally set output voltage is adjusted

through a unique communication protocol through the

single EN pin.

The IC is available in a 12-pin, 3mm x 3mm x 0.5mm,

ultra-thin DFN package with exposed pad and 0.5mm

lead spacing to facilitate placement on extremely narrow

circuit boards and a 24-pin, 4mm x 4mm, thin QFN pack-

age with exposed pad.

Applications

OLED Displays

Phone, DSC Displays

Automobile Navigation

Features

S 2.3V to 4.2V Input Operating Voltage Range

S High-Performance PWM Step-Up Regulator

Fixed 4.6V, 250mA Output

High Accuracy (±1%)

1.4MHz Switching Frequency

Built-In 6V/0.25I n-Channel MOSFET with

Lossless Current Sensing

Built-In 6V/0.5I p-Channel MOSFET

Synchronous Rectifier

Cycle-by-Cycle Current Limit

More than 85% Efficiency at 150mA

Good Low-Duty Factor Operation

S High-Performance PWM Inverting Regulator

Programmable 250mA Output

High Accuracy (±1%)

Adjustable Controlled-Output-Voltage Slew Rate

1.4MHz Switching Frequency

Built-In 14V/0.25I p-Channel Power MOSFET

with Lossless Current Sensing

Built-In 14V/0.25I n-Channel Power MOSFET

Synchronous Rectifier

Cycle-by-Cycle Current Limit

More than 80% Efficiency at 150mA

S True Shutdown for Both Outputs

S Timer-Delayed Output Undervoltage Shutdown for

Both Outputs

S Thermal-Overload Protection

S 12-Pin, 3mm x 3mm Ultra-Thin DFN Package and

24-Pin, 4mm x 4mm TQFN Package

19-5653; Rev 0; 12/10

+Denotes a lead(Pb)-free/RoHS-compliant package.

*Future product—contact factory for availability.

**Exposed pad.

Ordering Information

True Shutdown is a trademark of Maxim Integrated Products, Inc.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

MAX17116EVC+

-40NC to +85NC

12 UTDFN**

MAX17116ETG+*

-40NC to +85NC

24 TQFN**

Summary of content (19 pages)

PAGE 1
9-5653; Rev 0; 12/10 TION KIT EVALUA BLE IL AVA A Dual-Output DC/DC Power Supply for AMOLED The MAX17116 includes two current-mode 1.4MHz switch mode power-supply (SMPS) regulators for activematrix organic light-emitting diode (AMOLED) displays. The positive supply is provided by a step-up regulator with a synchronous rectifier. The negative supply is provided by an inverting regulator with a synchronous rectifier.
PAGE 2
MAX17116 Dual-Output DC/DC Power Supply for AMOLED ABSOLUTE MAXIMUM RATINGS IN, EN, IC, OUTP, LXP to AGND..............................-0.3V to +6V LXN to IN................................................................-14V to +0.3V STEP to AGND............................................-0.3V to (VIN + 0.3V) PGND to AGND.....................................................-0.3V to +0.3V OUTN to AGND........................................................-7V to +0.3V LXN to OUTN..........................
PAGE 3
Dual-Output DC/DC Power Supply for AMOLED (VIN = +3.7V, Circuit of Figure 2, VOUTP = +4.9V, VOUTN = -4.9V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER OUTN Maximum Regulation Voltage OUTN Fault Trip Level CONDITIONS MIN TYP MAX UNITS -1.530 -1.5 -1.
PAGE 4
MAX17116 Dual-Output DC/DC Power Supply for AMOLED ELECTRICAL CHARACTERISTICS (VIN = +3.7V, Circuit of Figure 2, VOUTP = +4.9V, VOUTN = -4.9V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS IN Input Supply Range IN Undervoltage-Lockout Threshold VIN rising, hysteresis = 200mV IN Quiescent Current EN = IN, no load OUTP Quiescent Current EN = IN, no load MIN MAX UNITS 2.3 TYP 4.2 V 1.8 2.2 V 90 FA 2.5 mA 1.
PAGE 5
Dual-Output DC/DC Power Supply for AMOLED (VIN = +3.7V, Circuit of Figure 2, VOUTP = +4.9V, VOUTN = -4.9V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 400 Fs TIMING SPECIFICATIONS Enable Start Delay tEN_DLY (Note 3) EN Pulse Stop Time tSTOP (Note 3) 250 EN Turn-Off Delay tOFF_DLY (Note 3) 50 70 Fs EN Pulse Frequency 50% duty factor 12 250 kHz Fs Note 1: Limits are 100% production tested at TA = +25NC.
PAGE 6
Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) STEP-UP REGULATOR OUTPUT LOAD REGULATION vs. LOAD CURRENT VIN = 3.7V VEN 0V 2V/div V 0V OUTP 5V/div 0V VLXP 5V/div 0V VOUTN 5V/div 0V VLXN 5V/div 90 VIN = 4.2V 80 70 VIN = 2.3V 60 50 40 -0.1 -0.2 -0.3 -0.4 -0.5 10 1ms/div 0 MAX17116 toc03 100 LOAD-REGULATION ERROR (%) MAX17116 toc01 MAX17116 toc02 STEP-UP REGULATOR EFFICIENCY vs.
PAGE 7
Dual-Output DC/DC Power Supply for AMOLED BUCK-BOOST REGULATOR OUTPUT LOAD REGULATION vs. LOAD CURRENT MAX17116 toc09 MAX17116 toc08 0.9 0.8 LOAD REGULATION ERROR (%) BUCK-BOOST REGULATOR LOAD TRANSIENT (20mA 30mA) 0.7 VOUTN (AC-COUPLED) 20mV/div 0.6 0V 0.5 0.4 0.3 0.2 LOAD CURRENT 20mA/div 0.1 0 0mA -0.1 -0.
PAGE 8
Dual-Output DC/DC Power Supply for AMOLED 2 11 LXP 10 OUTP 9 OUTP 8 AGND 7 I.C. OUTN 3 OUTN 4 EN 5 STEP MAX17116 EP 6 LXP OUTP OUTP AGND I.C. 14 13 12 N.C. N.C. 20 11 N.C. N.C. 21 10 N.C. 9 N.C. 8 N.C. 7 N.C. MAX17116ETG+ N.C. 22 N.C. 23 + IN 24 1 2 3 4 5 6 STEP LXN 15 EN PGND 16 OUTN 12 17 OUTN 1 18 N.C.
PAGE 9
Dual-Output DC/DC Power Supply for AMOLED VIN 2.3V TO 4.2V C2 4.7FH C1 4.7FF L1 4.7FH L2 4.7FH IN LXP LXN ELVSS -5.2V TO -2.2V 250mA OUTP C3 10FF MAX17116 OUTN C4 10FF PGND EN AGND STEP EP ON/OFF AND ELVSS ADJ Figure 2. MAX17116 Typical Operating Circuit The device's typical operating circuit is shown as Figure 2. The input supply voltage range is from 2.3V to 4.2V. The output voltage ELVDD is a fixed voltage of 4.6V (typ) and the ELVSS voltage is adjustable from -5.4V to -1.
PAGE 10
MAX17116 Dual-Output DC/DC Power Supply for AMOLED VIN 2.3V TO 4.2V IN LXP RDAM_P P1 IN P2 OUTP ELVDD 4.6V/250mA P INV PWM LXN BST PWM N1 N ELVSS -5.4V TO -1.5V 250mA PGND OUTN RDAM_N MAX17116 SEQUENCE AND ELVSS ADJUSTMENT PGND REF AGND STEP EN EP ON/OFF AND ELVSS ADJ Figure 3. MAX17116 Functional Diagram Detailed Description The MAX17116 includes two current-mode 1.4MHz SMPS regulators for AMOLED displays.
PAGE 11
Dual-Output DC/DC Power Supply for AMOLED The regulator controls the output voltage and the power delivered to the output by modulating duty cycle D of the internal power MOSFET in each switching cycle. An error amplifier compares the feedback signal with an internal reference voltage and changes its output internal compensation node with its pole/zero series resistor and capacitor to set the peak inductor current.
PAGE 12
MAX17116 Dual-Output DC/DC Power Supply for AMOLED Table 3. Inverting Regulator Output Voltage with EN Pulses EN PULSES VOUTN (V) EN PULSES VOUTN (V) 1 -5.4 22 -3.3 2 -5.3 23 -3.2 3 -5.2 24 -3.1 4 -5.1 25 -3.0 5 -5.0 26 -2.9 6 -4.9 27 -2.8 7 -4.8 28 -2.7 8 -4.7 29 -2.6 9 -4.6 30 -2.5 10 -4.5 31 -2.4 11 -4.4 32 -2.3 12 -4.3 33 -2.2 13 -4.2 34 -2.1 14 -4.1 35 -2.0 15 -4.0 36 -1.9 16 -3.9 37 -1.8 17 -3.8 38 -1.7 18 -3.7 39 -1.
PAGE 13
Dual-Output DC/DC Power Supply for AMOLED MAX17116 OUTN FIRST TRANSITION STARTUP SHUTDOWN VIN OV VEN OV VOUTP OV OV VOUTN tEN_DLY tSS_BST tSS_INV OUTP SOFT-START OUTN SOFT-START tSTOP tOFF_DLY OUTP, OUTN DISCHARGE Figure 4. MAX17116 Power-On/-Off Timing Sequence Undervoltage Lockout (UVLO) The UVLO circuit compares the input voltage at IN with the UVLO threshold (2.0V, typ) to ensure the input voltage is high enough for reliable operation.
PAGE 14
MAX17116 Dual-Output DC/DC Power Supply for AMOLED Thermal Protection The MAX17116 includes a thermal-protection circuit. Thermal-overload protection prevents excessive power dissipation from overheating the device. When the junction temperature exceeds TJ = +160NC (typ), the device shuts down. Cycling the input voltage (below the UVLO falling threshold) or bringing EN low for more than 70Fs clears the fault latch and reactivates the device.
PAGE 15
Dual-Output DC/DC Power Supply for AMOLED 2) Calculate the maximum DC current in the inductor and select an inductor whose DC current rating is greater than the maximum DC current calculated: ILP(DC_MAX) = I OUTP2(MAX) × VOUTP VIN(MIN) × ηP(MIN) 200mA × 4.6V = 2.3V × 0.81 = 493mA ∆ILP_RIPPLE = ( = 493mA + ) ∆ILP_RIPPLE 2 2.3V × (4.6V - 2.3V) 2 × 4.7µH × 4.6V × 1.4MHz = 580mA Inverting Converter Inductor LN Use the following procedure to choose the inductor for the inverting converter.
PAGE 16
MAX17116 Dual-Output DC/DC Power Supply for AMOLED OUTP and OUTN Output Capacitor Selection The total output voltage ripple has two components: the capacitive ripple caused by the charging and discharging of the output capacitance, and the ohmic ripple due to the capacitor’s equivalent series resistance (ESR): Input Capacitor Selection The input capacitor reduces the current peaks drawn from the input supply and reduces noise injection into the IC. Two 4.7µF ceramic capacitors are used in Figure 2.
PAGE 17
Dual-Output DC/DC Power Supply for AMOLED PSYN1 = I 2 SYN1(RMS) The conduction power loss in the synchronous rectifier is: PSYN2 = I 2 × R DSON_SYN1 where: SYN2(RMS) × R DSON_SYN2 where: I SYN1(RMS) = ILP(DC_MAX) × (1- D1) × [1 + 1 ∆ILP_RIPPLE 2 ×( ) ] 3 ILP(DC_MAX) I SYN2(RMS) = ILN(DC_MAX) × (1- D 2 ) × [1 + 1 ∆ILN_RIPPLE 2 ×( ) ] 3 ILN(DC_MAX) RDSON_SYN1 is the on-resistance for the synchronous rectifier. RDSON_SYN2 is the on-resistance for the synchronous rectifier.
PAGE 18
MAX17116 Dual-Output DC/DC Power Supply for AMOLED 6) Make a single connection between the AGND and PGND planes together at a point closest to the PGND pin only. Connect the entire backside pad to PGND with a larger plane for good thermal performance. Make no other connections between these two ground planes.
PAGE 19
Dual-Output DC/DC Power Supply for AMOLED REVISION NUMBER REVISION DATE 0 12/10 DESCRIPTION Initial release PAGES CHANGED — 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.