MP3312GC

MP3312 MPS | Alldatasheet

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Technical content

2.7V-5.5V Input , 38V OVP, Dual-Channel White LED Driver MP3312 Rev. 1.02 www.MonolithicPower.com 1 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. The Future of Analog IC Technology

DESCRIPTION

The MP3312 is a dual-channel step-up WLED driver with integrated 40V MOSFET, and supports 2.7V to 5.5V power supply input. It uses peak current mode to regulate the LED current which is set by external resistor. The MP3312 employs 1.2MHz fixed switching frequency. It features supporting both PWM input analog dimming and digital analog dimming to accurately regulate the dimming current. The MP3312 integrates current source to balance LED current, which leads good ILED matching and accuracy performance. In addition, the MP3312 has LED open and short protection, cycle by cycle current limit protection, and thermal shutdown protection. It is available in tiny WLCSP1.35x1.35-9 package.

FEATURES

• 2.7V~5.5V Input Voltage
• 1.2MHz Switching Frequency
• Dual Channels Support up to 30mA/String
• 1% Current Matching Between LED Channels
• +/-2% Current Accuracy
• 38V OVP Protection
• PWM Input Analog Dimming Mode
• 5kHz to100kHz PWM Input Analog Dimming
• 1-Wire Interface for Digital Dimming
• 9-bit Dimming Resolution
• Internal Soft Start to Reduce Inrush Current
• Available in WLCSP1.35x1.35-9 Package

APPLICATIONS

• Feature Phone and Smart Phones
• Tablets
• GPS Receivers
• <10 inch LCD video displays with one-cell Li- ion battery All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION 2.5 3 3.5 4 4.5 5 5.5 6

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 2 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved.

ORDERING INFORMATION

Part Number* Package Top Marking MP3312GC WLCSP1.35x1.35-9 BU * For Tape & Reel, add suffix –Z (e.g. MP3312GC–Z); PACKAGE REFERENCE Package Diagram WLCSP1.35x1.35-9 ABSOLUTE MAXIMUM RATINGS (1) Continuous Power Dissipation (TA = 25°C) (2) Recommended Operating Conditions (3) Thermal Resistance (4) θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature T J (MAX), the junction-to- ambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation a t any ambient temperature is calculated by P D (MAX) = (T J (MAX)-TA)/θJA. Exceeding the maximum allowable powe r dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanen t damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 3 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved.

ELECTRICAL CHARACTERISTICS

VIN =3.7V, VEN = VPWM= HIGH, Typical Values are at TA = 25°C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Unit Power Supply Operating Input Voltage V IN 2.7 5.5 V Supply Current (Quiescent) I Q VIN=3.7V, VEN= VPWM= High, no load with switching 1 2 mA Supply Current (Shutdown) I ST V EN=0V, VIN=3.7V 1 μA Input UVLO Threshold V IN_UVLO Rising Edge 2.4 2.6 V Input UVLO Hysteresis 200 mV OSCILLATOR Switching Frequency f SW 1 1.2 1.4 MHz Maximum Duty Cycle D MAX 93 95 % Minimum On Time(5) TON_MIN 100 ns Power Switch Main Switch On-Resistance RDSON_M VIN=3.7V 0.2 Ω Error Amplifier Error Amplifier Transconductance gm 370 uS Max Sink/Source Current 42 μA Current Regulation VLEDx Regulation Voltage V REG ILED1=ILED2=20mA 240 mV ISET Pin Voltage VISET 1.207 1.232 1.247 V Current Multiplier K ISET 1020 Current Accuracy I ISET =20uA, (|IMIN-IISET|/IISET,|IMAX-IISET|/ IISET) -2 2 % Current Matching I ISET =20uA, (IMAX –IMIN) /IAVG 1 2 % Current Sink Max Output Current 30 mA EN & PWM Logic PWM Input High Threshold V PWM_HI V PWM Falling 1.2 V PWM Input Low Threshold V PWM_LO VPWM Rising 0.4 V EN High Voltage V EN_HIGH VEN Rising 1.2 V EN Low Voltage V EN_LOW V EN Falling 0.4 V EN & PWM Pull Down Resistor R PD 800 k Ω EN Low Logic To Shutdown Time TSD_EN EN High to Low 2.5 ms PWM Low Logic To Shutdown Time TSD_PWM PWM High to Low 20 ms Minimum PWM On Time T PO_MIN 200 ns

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 4 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. ELECTRICAL CHARACTERISTICS (continued) VIN =3.7V, VEN = VPWM= HIGH, Typical Values are at TA = 25°C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Unit Protection OVP Voltage VOVP 37 38 39.5 V Cycle-Cycle Current Limit I LIM Max Duty Cycle 1.2 1.8 A Startup Current Limits(5) ILIM_START Max Duty Cycle 1 A Time Step for Half Current Limit(5) TLIM_HALF 6 ms LEDx Threshold when No Switching 560 mV LEDx Over Voltage Threshold V OVP_LED 4.5 5 5.5 V Thermal Shutdown Threshold T ST 150 °C Thermal Shutdown Hysteresis 25 °C 1-Wire Interface 1-Wire Detection Delay Time t DELAY 100 μs 1-Wire Detection Time t DETECTION 260 μs 1-Wire Detection Window t WIN 1 ms Start Time of Program Stream t START 2 μs End Time of Program Stream t EOS 2 360 μs High Time of Logic 0 Bit t H_LB 5 180 μs Low Time of Logic 0 Bit t L_LB 3* t H_LB 360 μs High Time of Logic 1 Bit t H_HB 3* t L_HB 360 μs Low Time of Logic 1 Bit t L_HB 5 180 μs Acknowledge Valid Time t ACKval 2 μs Duration of Acknowledge Signal t ACK 512 μs Acknowledge Output Voltage Low(6) V ACKL Open drain, RPULLUP= 15 k Ω to VIN 0.4 V Notes: 5) guarantee by design and characterization 6) ACK signal is active 0 (when ACK signal is true , data line is pulled down by chip),and this signal only reply when RFA bit is set to 1.If you want use ACK signal, the master should have an open-drain output, and data line should be pulled high by master with a resistor load.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 5 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.7V, 6*LEDs/string, ILED1=ILED2=20mA, L = 4.7µH, TA = 25°C, unless otherwise noted. 0 20 40 60 80 100 0 20 40 60 80 100 2.5 3 3.5 4 4.5 5 5.5 6

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 6 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 3.7V, 6*LEDs/string, ILED1=ILED2=20mA, L = 4.7µH, TA = 25°C, unless otherwise noted. VSW 10V/div. VOUT 10V/div. IL 200mA/div. ILED 50mA/div. VSW 10V/div. VEN 5V/div. IL 200mA/div. ILED 50mA/div. VSW 10V/div. VEN 5V/div. IL 200mA/div. ILED 50mA/div. VSW 10V/div. VPWM 5V/div. VOUT 20V/div. ILED 20mA/div. VSW 10V/div. VIN 2V/div. IL 200mA/div. ILED 50mA/div. VSW 10V/div. VIN 2V/div. IL 200mA/div. ILED 50mA/div. VSW 10V/div. VCOMP 1V/div. VEN/1-WIRE 2V/div. ILED 20mA/div. VSW 20V/div. VOUT 20V/div. IL 200mA/div. ILED 50mA/div. VSW 20V/div. VLED1 20V/div. IL 200mA/div. ILED 20mA/div.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 7 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. PIN FUNCTIONS Pin # Name Description A1 ISET Full scale LED current set pin. Connecting a resistor between this pin and GND sets the full scale current. A2 LED2 LED2 current sink pin. A3 LED1 LED1 current sink pin. B1 PWM PWM signal input pin. 5kHz to 100kHz PWM Signal is recommended to this pin to do the analog current dimming. Low logic for >20ms shuts down the IC. B2 COMP Internal error amplifier output pin. Connect a capacitor to compensate the system. B3 GND GND pin. C1 EN Enable and 1wire input pin. High logic enables the IC and low logic >2.5ms shuts down the IC. C2 VIN Power supply input pin. Connect a ceramic capacitor nearby this pin to bypass the IC. C3 SW Drain connection of the internal N-CH power MOSFET.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 8 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. FUNCTIONAL BLOCK DIAGRAM OSC RAMP PWM Control EA PWM ComparatorVREF VIN VOUT SW LED1 GND Current ControlFeedback Control Min. Max. Short Protection Analog Dimming EN Detection LED2 ISET EN OVP Shutdown PWM COMP EN L1 D1 C1 C2 VIN Figure 1— Functional Block Diagram

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 9 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. OPERATION The MP3312 employs the fixed switching frequency, peak current mode control architecture and 2 regulated current sinks to power the LED array. The operation of the MP3312 can be understood by referring to the below function block diagram. System Startup Either pulling EN or PWM to high enables the IC operation while pulling EN to GND for >2.5ms or pulling PWM to GND for >20ms shuts down the IC. When enabled, the MP3312 checks the topology connection first. The MP3312 also checks other safety limits, including UVLO and over-temperature protection (OTP). If all the protections pass, the chip then starts boosting the step-up converter with an internal soft-start. It is recommended that the enable signal occurs after the establishment of the input voltage and PWM dimming signal during the start-up sequence to avoid large inrush current. Switching Operation At the start of each oscillator cycle the main low side FET (M1) is turned on through the control circuitry. To prevent sub-harmonic oscillation at duty cycle greater than 50 percent, a stabilizing ramp is added to the output of the current sense amplifier and the result is fed into the positive input of the PWM generation comparator. When this voltage equals the output voltage of the error amplifier the main power FET is turned off. Then the inductor current flows through the free-wheeling diode, which forces the inductor current to decrease. The output voltage of the internal error amplifier is an amplified signal of the difference between the reference voltage and the feedback voltage. The converter automatically chooses the lowest active LEDX pin voltage to provide a high- enough bus voltage to power all the LED arrays. If the feedback voltage drops below the reference, the output of the error amplifier increases. It results in more current flowing through the MOSFET, thus increasing the power delivered to the output. This forms a closed loop that regulates the output voltage. Dimming Control MP3312 supports analog dimming and 1-wire digital set dimming mode to regulate the WLED current. To do analog dimming, apply a PWM signal to PWM pin by adjusting the LED current amplitude. The internal filter is integrated and the PWM signal with 5k~100kHz range is supported. Internal dimming signal duty detection circuit automatically changes the internal reference lineally to regulate the current. In addition, the EN pin supports 1-wire interface to do current dimming control. The 1-wire description and protocol details are as follow. 1-wire Interface 1-wire interface is based on master-slave structure which is designed for digital dimming. The EN pin is multipurpose as single port to receive LED brightness data. The rate to detect the bit can automatically range from 1.39kBit/sec to 50kBit/sec. The command sent to chip (slave) contains 24 bits, 9-bit dimming data, 8-bit device address and RFA bit are included. Chip detects the bit in series and it transmits the LSB first and MSB finally. The control bits description is as below and Figure 2 shows the command bytes structure in detail.

• D0-D8 are the dimming data bits which achieve 9-bit dimming resolution
• Bit9 and bit11-bit15 is reserved. Set to 0
• RFA bit indicates master needs Request of Acknowledge or not.
• Device address byte is DA0-DA7. The device address byte is set to 0x8F.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 12 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. Cycle-by-Cycle Current Limit Protection MP3312 provides cycle-by-cycle current limit protection to avoid any damage due to too large current rating. During startup, the current limit is clamped to 1A for around 6ms to avoid output overshoot and inrush current. After that, the current limit returns back to normal 1.8A. Open String Protection Open string protection is achieved by detecting the VOUT pin. If the LED string is open, the feedback voltage is lower than the reference voltage, thus the COMP rises up and keeps charge the output capacitor until VOUT pin hits the protection point VOVP. Then the IC stops switching and shuts down till VIN and EN is reset for enable again. Unused LED Channel In some cases, if one LED current channel is not used, connect the corresponding LEDx to GND to remove it from the control loop. Short String Protection The MP3312 monitors the LEDX pin voltage to judge if the short string occurs. If one string is short, the respective LEDX pin will be pulled up to the boost output and tolerate high voltage stress. If the LEDX pin voltage is higher than 5 V and LED current is larger than 8% full-scale setting current, the short string condition is detected and if such condition lasts longer than 8ms, the fault string current source is disabled till VIN and EN is reset for enable again. Thermal Shutdown Protection To prevent the IC operate at exceedingly high temperature, thermal shutdown is implemented in this chip by detecting the silicon die temperature. When the die temperature exceeds the upper threshold 150℃, the IC shutdowns and recovers to normal operation when die temperature drops below lower threshold. Typically, the hysteresis value is 25°C.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 13 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved.

APPLICATION INFORMATION

The full scale LED current can be set through the current setting resistor on the FB pin. = Ω ISET ISET V( V )ILED(mA) *1020R( k ) For VISET=1.232V, RISET=63.4kΩ, the LED current is set to 20mA. Please do not leave ISET pin open. Selecting the Input Capacitor The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. The input capacitor impedance at the switching frequency should be much less than the input source impedance to prevent the high-frequency switching current from passing through to the input. Use ceramic capacitors with X5R or X7R dielectrics for their low ESR and small temperature coefficients. For most applications, a 1uF~4.7 μF ceramic capacitor is ok. Selecting the Inductor The MP3312 requires an inductor to supply a higher output voltage while being driven by the input voltage. A larger value inductor results in less ripple current, resulting in lower peak inductor current and reducing stress on the internal N-channel MOSFET. However, the larger value inductor has a larger physical size, higher series resistance, and lower saturation current. Choose an inductor that does not saturate under the worst-case load conditions. Select the minimum inductor value to ensure that the boost converter works in continuous conduction mode with high efficiency and good EMI performance. Calculate the required inductance value using the equation: OUT SW LOAD η V D ( 1 D )L 2 f I IN OUT V D1 V=− Where V IN and V OUT are the input and output voltages, f SW is the switching frequency, I LOAD is the total LED load current, and η is the efficiency. The switching current is used for the peak current mode control. In order to avoid hitting the current limit, the worst-case inductor peak current should be less than 80% of the current-limit I LIM. Generally, a 4.7uH~10uH inductor is ok to cover most of the applications. Note that the system efficiency is dependent on the DC resistance of inductor, and larger DC resistance causes larger power loss. Selecting the Output Capacitor The output capacitor keeps the output voltage ripple small and ensures feedback loop stability. The output capacitor impedance must be low at the switching frequency. Ceramic capacitors with X7R dielectrics are recommended for their low ESR characteristics. Care must be taken that ceramic capacitance is also dependent on the voltage rating; DC bias voltage and the value can loss as much as 50% of its capacitance at its rated voltage rating. Please leave enough voltage rating margin when select the component. In addition, too low capacitance will cause the loop instability. For most applications, a 1μF~4.7μF ceramic capacitor is ok. Selecting the External Schottky Diode To optimize the efficiency, a high-speed and low reverse recovery current schottky diode is recommended. Make sure the diode’s average and peak current rating exceeds the output average LED current and the peak inductor current. In addition, the diode’s break-down voltage rating should be large than the maximum voltage across the diode. Usually, unexpected high frequency spike voltage can be seen across the diode when the diode turns off. So, leaving some voltage rating margin is always needed to guarantee normal long term operation when selecting a diode. Layout Considerations Careful attention must be paid to the PCB board layout and components placement. Proper layout of the high frequency switching path is critical to prevent noise and electromagnetic interference problems. The loop of MP3312’s internal low side MOSFET, schottky diode, and output capacitor is flowing with high frequency ripple current, it must be minimized. So the input and output capacitor should be placed to IC as close as possible.

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER MP3312 Rev. 1.02 www.MonolithicPower.com 14 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. TYPICAL APPLICATION CIRCUITS Figure 7— Typical Application for dual string 6LEDs, 20mA/string

MP3312 － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP3312 Rev. 1.02 www.MonolithicPower.com 15 1/13/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved.

PACKAGE INFORMATION

WLCSP1.35X1.35-9 SIDE VIEW BOTTOM VIEW NOTE: PIN 1 ID MARKING TOP VIEW PIN 1 ID INDEX AREA RECOMMENDED LAND PATTERN PIN 1 ID