MP3370GN-Z

MP3370 Single String, 38V Vout Boost LED Driver with Current Source DESCRIPTION FEATURES The MP3370 is a fixed-frequency boost converter with current source. It is ideal for medium-to-high current boost LED driver applications.             The MP3370 regulates the output voltage up to 38V to drive more LEDs with an integrated 100mΩ/50V low-side MOSFET. The peak current-mode regulation and external compensation components allow the MP3370 control loop to be optimized over a wide variety of input voltage, output voltage, and load current applications. The internal soft-start, cycle-by-cycle current limiting and input under voltage lockout prevent overstressing or damage to sensitive external circuitry at start-up and fault conditions. The MP3370 supports PWM dimming and analog dimming for flexible dimming applications. Input Range of 3.5V to 36V More than 3A Peak Current Limit Internal 100mΩ 50V Power Switch Analog/PWM Dimming High Efficiency Under-Voltage Lockout Protection LED Open/Short Protection Inductor/Diode Short Protection 43.5V Over-Voltage Protection Soft-Start Operation Thermal Shutdown SOIC8-EP Package APPLICATIONS   Middle Size LCD Backlighting General Lighting All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS”, the MPS logo, and “Simple, Easy Solutions” are trademarks of Monolithic Power Systems, Inc. or its subsidiaries. The MP3370 is available in the thermally enhanced SOIC8-EP package with exposed pad. TYPICAL APPLICATION MP3370 Rev 1.0 1/16/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 1 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE ORDERING INFORMATION Part Number* MP3370GN Package SOIC8-EP Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MP3370GN–Z) TOP MARKING MP3370: Part number LLLLLLLL: Lot number MPS: MPS prefix Y: Year code WW: Week code PACKAGE REFERENCE TOP VIEW VIN 1 8 VCC 2 SW 7 GND EN/DIM 3 6 LED COMP 4 5 ISET EXPOSED PAD ON BOTTOM CONNECT TO GND SOIC8-EP MP3370 Rev 1.0 1/16/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 2 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE PIN FUNCTIONS Pin # Name 1 VIN 2 VCC 3 EN/DIM 4 COMP 5 ISET 6 7 LED GND 8 SW Description Input Supply Pin. VIN Supplies power to the IC. 5V LDO output pin. VCC provides power for internal logic and gate driver. Place a ceramic capacitor as close as possible to this pin to reduce noise. EN and Dimming Pin. When a low-level signal remains for >20ms, the IC is disabled. When the PWM signal >5kHz on this pin, the IC operates in analog dimming mode. When the PWM signal 2V With switching, 400kHz VIN = 6V to 25V VIN rising Units V 0.5 1.0 μA 3 4 5 2.8 3 mA mA V 3.2 0.4 fSW 350 85 1 400 94 100 450 3 ISET voltage VISET LED current ILED VSW = 25V ILED = 120mA ILED = 300mA RISET = 24.9kΩ, Tj = 25°C 65 300 540 1.2 -2.5% 300 41 43.5 Thermal shutdown (4) V V MΩ kHz % mΩ A μA mV mV V +2.5% mA 46 C V 150 www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. V mV 1.2 VHD MP3370 Rev 1.0 1/16/2019 Max 36 100 LEDX regulation voltage OVP threshold Typ 4 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE TYPICAL PERFORMANCE CHARACTERISTICS Performance waveforms are tested on the evaluation board of the Design Example section. VIN = 12V, L = 22µH, LED=12S, FSW=400kHz, ISET=300mA, TA = 25° C, unless otherwise noted EN/DIM Power On Steady State CH1: SW 20V/div. CH1: SW 20V/div. CH2: VOUT 20V/div. CH2: EN/DIM 5V/div. CH3: IL 1A/div. CH3:IL 1A/div. CH4: ILED 200mA/div. CH4: ILED 200mA/div. 4µs/div. 10ms/div. EN/DIM Power On EN/DIM Power On FDIM=10kHz , Duty=50% FDIM=200Hz , Duty=50% CH1: SW 20V/div. CH1: SW 20V/div. CH2: EN/DIM 5V/div. CH2: EN/DIM 5V/div. CH3:IL 1A/div. CH3:IL 1A/div. CH4: ILED 100mA/div. CH4: ILED 200mA/div. 10ms/div. 20ms/div. PWM Dimming PWM Dimming FDIM=200Hz , Duty=50% FDIM=200Hz , Duty=0.1% CH1: SW 20V/div. CH1: SW 20V/div. CH2: EN/DIM 3V/div. CH2: EN/DIM 2V/div. CH3:IL 1A/div. CH3:IL 2A/div. CH4: ILED 500mA/div. CH4: ILED 200mA/div. 2ms/div. MP3370 Rev 1.0 1/16/2019 4µs/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 5 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. VIN = 12V, L = 22µH, LED=12S, FSW=400kHz, ISET=300mA, TA = 25° C, unless otherwise noted Analog Dimming Analog Dimming FDIM=10kHz , Duty=50% FDIM=10kHz , Duty=1% CH1: SW 20V/div. CH1: SW 20V/div. CH2: EN/DIM 3V/div. CH2: EN/DIM 2V/div. CH3:IL 1A/div. CH3:IL 2A/div. CH4: ILED 200mA/div. CH4: ILED 10mA/div. 40µs/div. 2µs/div. Open LED String Protection Short LED String Protection CH1: SW 20V/div. CH1: SW 20V/div. CH2: VOUT 20V/div. CH2: VOUT 20V/div. CH3:ISHORT 1A/div. CH3:ISHORT 1A/div. CH4: ILED 200mA/div. CH4: ILED 200mA/div. 40µs/div. 4ms/div. Short Inductor Protection CH1: SW 20V/div. CH1: SW 20V/div. CH3:ISHORT 10A/div. CH3:ISHORT 10A/div. CH4: ILED 200mA/div. CH4: ILED 200mA/div. 10µs/div. MP3370 Rev 1.0 1/16/2019 Short Diode Protection 10µs/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 6 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE BLOCK DIAGRAM Figure 1: Functional Block Diagram MP3370 Rev 1.0 1/16/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 7 MP3370 – SINGLE STRING 38V BOOST LED DRIVER WITH CURRENT SOURCE OPERATION The MP3370 employs a fixed-frequency peakcurrent-mode step-up converter, with current source, to drive an integrated MOSFET to regulate the LED current programmable by an ISET pin resistor. Internal 5V Regulator The MP3370 includes an internal linear regulator (VCC). When VIN is greater than 5.5V, this regulator outputs a 5V power supply to the internal MOSFET switch gate driver and the internal control circuitry. The VCC voltage drops to 0V when the IC shuts down. The IC is disabled until VCC exceeds the UVLO threshold. System Start-Up When the input voltage is higher than UVLO, and EN/DIM is higher than the rising threshold, the IC starts boosting the step-up converter with an internal soft start. Step-Up Converter The MP3370 employs peak-current-mode control to regulate the output energy. At the beginning of each switching cycle, the internal clock turns on the internal N-MOSFET. A stabilizing ramp added to the output of the current sense amplifier prevents sub-harmonic oscillations for duty cycles greater than 50%. This result is fed into the PWM comparator. When the summed voltage reaches the output voltage of the error amplifier, the internal MOSFET will turn off. The output voltage of the internal error amplifier is an amplified signal of the difference between the reference voltage and the LED voltage. 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. Under light-load operation, especially in the case of VOUT ≈ VIN, the converter runs in pulse-skipping mode where the MOSFET turns on for a minimum on-time, and then the converter discharges the power to the output for the remaining period. The external MOSFET MP3370 Rev 1.0 1/16/2019 remains off until the output voltage needs boosting again. Enable & Dimming The EN/DIM pin operates in different functions when different signals are applied on this pin. a. When EN/DIM is pulled high, the IC is enabled; when EN/DIM remains low for 20ms, the IC is disabled. b. PWM dimming (FPWM