MP3309GQG-Z

MP3309 2.7V-5.5V Input, 35V Output White LED Driver DESCRIPTION FEATURES The MP3309 is a WLED step-up converter for 2.7V to 5.5V input that uses peak-current mode to regulate the LED current sensed through an external, low-side resistor. The 200mV feedback voltage and synchronous rectification reduces power loss and reduces PCB space requirements. • • • • The MP3309 features a programmable switching frequency to optimize efficiency. It supports both analog and PWM dimming. In addition, the MP3309 has LED open protection, cycle-by-cycle current limit protection, Under voltage protection and thermal shutdown protection . 2.7V to 5.5V Input Voltage Analog and PWM Dimming Programmable Switching Frequency Low 200mV Feedback Voltage with ±1% Accuracy at Room Temperature Internal Soft Start Under-Voltage Lockout (UVLO), Thermal Shutdown, and Over-Current Protection (OCP) Available in a QFN-10 (1.4mmx1.8mm) Package • • • APPLICATIONS • • • Feature Phones and Smart Phones Tablets 20kHz PWM signal is recommended. Pull 2 pins high together when analog dimming is not used. Input Supply Pin. Provides power for internal power and logic circuits. Must be locally VIN bypassed. PWM Brightness Control/Enable. Apply a PWM signal for PWM dimming. The PWM duty is proportional to the LED current dimming —a lower dimming duty results in a EN/PWML smaller dimming current. For most applications, use a frequency range of 200Hz to 2kHz. A low-level signal longer than 20ms will shutdown the IC. Switching Frequency Set. Connect a resistor between this pin and GND to program FREQ the converter switching frequency. Do not leave this pin floating. LED Current Feedback. Regulates the voltage across the current sense resistor FB between FB and GND to 200mV. GND Ground. Power Switch Node. Drain of the internal low-side MOSFET. Connect the power SW inductor between SW and VIN pin. For non-synchronous mode, connect a Schottky diode between this pin and VOUT. Output Voltage. Internally connected to the source of the synchronous MOSFET. For VOUT non-synchronous mode, connect a Schottky diode between SW pin and this pin. . Booststrap. Connect a capacitor between SW and BST pin to provide the BST synchronous MOSFET gate driver. PWMH www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 5 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER BST VIN VOUT BG&Logic Control Unit EN Detect EN/PWML M2 Regulator SW OSC PWMH VREF&DPWM PWM Control RAMP DPWM EN/PWML VREF EA FREQ LED M1 GND PWM Comparator OSC FB Figure 1: Functional Block Diagram MP3309 Rev. 1.1 7/25/2022 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 6 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER OPERATION The MP3309 uses the peak current mode control architecture to regulate the current flowing through the white LEDs string. The operation of the MP3309 can be understood by referring to the function block diagram. At the start of each oscillator cycle, the control circuit turns on the low-side MOSFET (LS-FET, M1). A stabilizing ramp added to the output of the current-sense amplifier, which then feeds into the positive input of the PWM comparator, prevents sub-harmonic oscillations at duty cycles greater than 50%. When the input to the PWM comparator equals the output voltage of the error amplifier. M1 turns off. Then the inductor current flows through the synchronous power MOSFET, which forces the inductor current to decrease. The voltage at the output of the error amplifier is the amplified difference between the 200mV reference voltage and the feedback voltage. If the feedback voltage starts to drop, the output of the error amplifier increases, increasing the current flowing through the M1, thus increasing the power to the inductor and output power. This method accurately regulates the LED current. System Startup When enabled, the MP3309 checks safety limits, including UVLO and over-temperature protection (OTP), over-current protection after passing the OVP test. If all the protection tests pass, the chip then starts boosting the step-up converter with an internal soft-start. When enable on, since for soft-start, the current limit drops to 0.8A during startup to prevent a large inrush current. This low-current-limit time lasts for 5ms after the IC is enabled. Dimming Control The MP3309 provides two dimming methods: PWM and analog dimming mode. For PWM dimming, apply a PWM signal to the EN/PWML pin. The LED current is then segmented as per the PWM signal and the average LED current equals: Iset  Ddim .Where Ddim is the PWM duty cycle, and Iset is the LED current amplitude. When PWM signal is high, MP3309 Rev. 1.1 7/25/2022 the converter operates in normal mode. Conversely, when the PWM amplitude is low, the converter stops switching. Make sure that the PWM-signal low-level time is less than 20ms or the IC will shutdown. Use a 200Hz-to2kHz PWM-dimming frequency for most dimming ratio requests. For analog dimming, set the LED current amplitude through an external PWM signal. For MP3309, implement analog dimming by the PWMH pins and apply a PWM signal. An internal RC fliter filters the PWM signal. The LED current amplitude equals Iset×Ddim, where Ddim is the PWM duty cycle and Iset is the LED current amplitude. Use a>20kHzPWM signal to improve filtering performance. Open-String Protection The MP3309 monitors the VOUT pin for openstring protection. If the LED string is open, the feedback voltage is lower than the reference voltage. The COMP then rises and charges the output capacitor until the VOUT voltage reaches the protection point, VOVP. The OVP point of MP3309 is 35.5V. Typically, the hysteresis is 2.5V. The IC stops switching when VOUT reaches the OVP threshold, the IC resumes function when VOUT drops below the threshold. Input Under-Voltage Protection When VIN exceeds 2.5V, the converter starts to charge the internal reference and provides power to the internal control circuitry. There is UVLO hysteresis, approximately 200mV, as VIN falls. The IC shuts down when the input voltage drops below 2.3V. Thermal-Shutdown Protection Thermal shutdown prevents the IC from operating at exceedingly high temperatures. When the die temperature exceeds the upper threshold (TST), the IC shutdowns and resumes normal operation when the die temperature drops below lower threshold. Typically, the hysteresis is 25°C. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 7 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER APPLICATION INFORMATION Selecting the Switching Frequency The switching frequency of the step-up converter can be programmed from 300kHz to 1.2MHz. A resistor on the OSC pin sets the internal oscillator frequency for the step-up converter as per the equation below: fSW(kHz) = 120000 ROSC (k) For instance, if ROSC=200kΩ, the switching frequency is to 600kHz. Setting the LED Current Set the LED current through the current-setting resistor on the FB pin. ILED (mA) = VREF (V)  1000 RFB () For instance, if VREF=200mV, and RFB=10Ω, the LED current is 20mA. Do not leave the FB pin floating. 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 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, use a 2.2µF-to-10μF ceramic capacitor. Selecting the Inductor The MP3309 requires an inductor to boost its output voltage. A larger value inductor results in less ripple current, lowering both the peakinductor current and the stress on the internal N-channel MOSFET. However, the larger inductor is physically larger, has a higher series resistance, and a 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. MP3309 Rev. 1.1 7/25/2022 Calculate the required inductance value using the equation: η  VOUT  D  (1− D)2 L 2  fSW  ILOAD V D = 1 − IN VOUT Where VIN and VOUT are the input and output voltages, fSW is the switching frequency, ILOAD is the LED load current, and η is the efficiency. The switching current for peak-current mode. To avoid hitting the current limit, the worst-case inductor peak current should be less than 80% of the current limit, ILIM. 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. Selection must also account for the capacitance’s dependence on the voltage rating; with a DC bias voltage, the capacitor can lose as much as 50% of its capacitance at its rated voltage rating. Leave a sufficient voltage rating margin when select the component. Too-low or too-high capacitance will cause loop instability. For most applications, select a capacitor in the range of 0.1µF to 1μF. Internal Soft Start When enable on, IL current limit drop to half to prevent inrush during startup. 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 limit electromagnetic interference. The loop consisting of MP3309’s internal low-side MOSFET, synchronous MOSFET or diode, and output capacitor contains a high-frequency ripple current—minimize this loop. Place the input and output capacitor should as to the IC as possible. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 8 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER TYPICAL APPLICATION CIRCUITS L1 10μH R3 0Ω VIN C1 4.7μF/10V C2 10nF SW GND VIN BST OUT MP3309 PWMH PWMH C3 0.47μF /50V 8*LEDs PWMH EN/PWML EN/PWML FREQ FB R2 100k R1 10Ω GND Figure 2: Typical Application for Single String 8LEDs L1 10μH R3 0Ω VIN C2 10nF C1 4.7μF/10V SW GND VIN BST OUT MP3309 PWMH PWMH 3X3 LED Array C3 0.47μF /50V PWMH EN/PWML EN/PWML FREQ FB R2 150k GND R1 3.3Ω Figure 3: Typical Application for 3X3 LED Array MP3309 Rev. 1.1 7/25/2022 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 9 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER Figure 4: Typical Application for More Noise Robust Test MP3309 Rev. 1.1 7/25/2022 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 10 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER PACKAGE OUTLINE DRAWING FOR 10L FCQFN (1.4X1.8MM) PACKAGE INFORMATION MF-PO-D-0084 revision 2.0 QFN-10 (1.4mmx1.8mm) PIN 1 ID MARKING PIN 1 ID 0.10X45º TYP PIN 1 ID INDEX AREA BOTTOM VIEW TOP VIEW SIDE VIEW NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) LEAD COPLANARITY SHALL BE 0.10 MILLIMETERS MAX. 3) JEDEC REFERENCE IS MO-220. 4) DRAWING IS NOT TO SCALE. RECOMMENDED LAND PATTERN MP3309 Rev. 1.1 7/25/2022 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 11 MP3309 2.7V-5.5V INPUT, 35V OUTPUT, fs-PROGRAMMABLE, WHITE LED DRIVER REVISION HISTORY Revision # 1.0 1.01 Revision Date 11/6/2013 04/11/2014 1.02 09/23/2016 1.1 7/25/2022 Description Initial Release Updated the electrical parameters, including maximum duty, supply current, switching frequency, OVP voltage, current limit, and half-current limit in the Electrical Characteristics section Updated Table 1 Removed “Select Dimming Control Mode” Changed the default value of the EN bit and OVP bit register Added ordering information Updated Typical Performance Characteristics Added figure 4 Deleted descriptions related to the MP3309C functions Updated the Features section; updated the footnote below the Applications section Updated FREQ pin name Updated the Package Information section Pages Updated 3 9 11 11 2 4 10 All 1 5 11 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. MP3309 Rev. 1.1 7/25/2022 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2022 MPS. All Rights Reserved. 12