MP3428GL-P

MP3428 17A, 600kHz, 20V Wide Input Range, Synchronous Boost Converter in a small 3x4mm QFN Package MPS CONFIDENTIAL AND PROPRIETARY INFORMATION– INTERNAL USE ONLY DESCRIPTION FEATURES       The MP3428 is a 600kHz fixed-frequency, highefficiency, wide input range, current-mode boost converter with optional internal or external current-sensing configuration for highintegration and high-power applications. With a current limit above 17A, the MP3428 supports a wide range of applications including POS, Thunderbolt, Bluetooth Audio, Power Banks, and Fuel Cells. The MP3428 features a 10mΩ, 24V power switch and a synchronous gate driver for high efficiency. An external compensation pin gives the user flexibility in setting loop dynamics and obtaining optimal transient performance at all conditions.      3V-to-20V Wide Input Range Integrated 10mΩ Low-Side Power FET SDR Driver for Synchronous Solution >17A Switch-Current Limit Up to 97.5% Efficiency Optional Internal/External CurrentSensing Configuration External Soft-Start and Compensation for Higher Flexibility Programmable UVLO and Hysteresis < 1µA Shutdown Current Thermal Shutdown at 150℃ Available in a 3x4mm QFN-22 Package APPLICATIONS The MP3428 includes under-voltage lockout (UVLO), switching-current limiting and thermal shutdown (TSD) to prevent damage in the event of an output overload.       The MP3428 is available in a low-profile 22-pin 3mmx4mm QFN package. Thunderbolt Interface Notebooks and Tablets Bluetooth Audio Power Banks Fuel Cells POS Systems All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION VIN R4 L1 2.2uH Q1 4mΩ SW SENSE BST SDR OUT IN OFF ON EN VDD C1 22μF x 2 MP3428 R1 300kΩ R2 34kΩ COMP MODE C4 33nF C2 22μF x 3 FB SS C3 2.2μF MP3428 Rev. 1.0 10/10/2019 VOUT=12V/2.1A C6 0.1μF PGND AGND C5 6.8nF R3 9.1kΩ www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 1 MP3428 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE ORDERING INFORMATION Part Number* MP3428GL Package QFN-22 (3mm×4mm) Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MP3428GL–Z); TOP MARKING MP: MPS prefix: Y: year code; W: week code: 3428: first four digits of the part number; LLL: lot number; PACKAGE REFERENCE TOP VIEW MP3428 Rev. 1.0 10/10/2019 SW SW PGND PGND 20 19 18 17 BST 1 16 AGND SDR 2 15 SS OUT 3 14 FB EN 4 13 COMP MODE 5 12 VDD SENSE 6 11 IN SW 21 PGND 22 7 8 9 10 SW SW PGND PGND www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 2 MP3428 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance (5) SW ..................... –0.3V to +24V (28V for 5.5V). Also, EN can program Vin UVLO. Do not leave EN floating. Mode Select. Selects the internal or external current sensing mode. Connect to GND to use internal current-sensing block. If floating, use an external current-sense resistor. DO NOT pull MODE down to GND through a resistor. Voltage Sense. Voltage sensed between SENSE and IN. The voltage sensed between SENSE and IN determines the external current-sense signal. Power Switch Output. SW is the drain of the internal Power MOSFET. Connect the power inductor and output rectifier to SW. Power Ground. Input Supply. IN must be bypassed locally. Internal Bias Supply. Decouple with a 2.2μF ceramic capacitor as close to FB as possible. Compensation. Connect a capacitor and resistor in series to AGND for loop stability. Feedback Input. Reference voltage is 1.225V. Connect a resistor divider from VOUT to FB. Soft-Start Control. Connect a soft-start capacitor to SS. The soft-start capacitor is charged with a constant current. Leave SS disconnected if the soft-start is not used. Analog Ground. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 10 MP3428 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE FUNCTIONAL BLOCK DIAGRAM Figure 1. Functional Block Diagram MP3428 Rev. 1.0 10/10/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 11 MP3428 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE OPERATION The MP3428 is a 600kHz fixed-frequency, highefficiency, wide input range, current-mode boost converter with optional internal or external current-sensing configuration for highintegration and high-power applications (see Figure 1). switches to a normal frequency. In addition, the voltage on COMP is clamped within VSS+0.7V. During start-up the COMP voltage reaches 0.7V quickly, and then rises at the same rate of VSS. These two mechanisms prevent highinrush current from the input power supply. Boost Function SDR and BST Function The MP3428 uses constant frequency, peakcurrent mode, boost regulation architecture to regulate the feedback voltage. The MP3428 generates a synchronous gatedriving signal that complements the gate driver of the internal MOSFET. The SDR driver is powered from BST (5V, typically) and a low QG N-channel MOSFET (a gate-source threshold voltage lower than 3V is preferred). In highpower applications, using a synchronous rectifier switch improves overall conversion efficiency. If a synchronous rectifier switch is not used, float SDR. The 5V driver power-bootstrap voltage is powered from OUT. If output voltage is low (or the duty cycle is too low), BST voltage may not be regulated to 5V, triggering a BST_UVLO. A schottky diode from an external 5V source to BST is recommended, otherwise, the SDR driver signal may be lost. At the beginning of each cycle, the N-channel MOSFET switch Q is turned on, forcing the inductor current to rise. When floating MODE, the current at the source of switch Q is measured externally; then it is converted to a voltage by the current-sense amplifier. That voltage is compared to the error voltage on COMP (which is an amplified version of the difference between the 1.225V reference voltage and the feedback voltage). When these two voltages are equal, the PWM comparator turns off switch Q. This forces the inductor current into the output capacitor through the external rectifier, causing the inductor current to decrease. The peak-inductor current is controlled by the voltage on COMP, which in turn is controlled by the output voltage. To satisfy the load, the output voltage is regulated by the inductor current. Current mode regulation improves transient response and control loop stability. VDD Power MP3428 is powered by VDD. A ceramic capacitor no less than 2.2μF is required to decouple VDD. During start-up, VDD power is regulated by IN. Once the output voltage exceeds the input voltage, VDD is powered from VOUT (instead of VIN). This allows the MP3428 to maintain low Ron and high efficiency, even with low-input voltage. Soft-Start (SS) MP3428 uses one external capacitor on SS to control SW frequency during start-up. The operation frequency is initially ¼ of the normal frequency. As the SS capacitor is charged, the frequency increases continuously. When the voltage on SS exceeds ~0.65V, the frequency MP3428 Rev. 1.0 10/10/2019 Current Sensing Configuration The MP3428 offers the option of using the internal circuit or an external resistor to sample the inductor current. When using the internal current sense, MODE must be connected directly to GND before powering on. Meanwhile, SENSE should be connected to IN. In this configuration, sensed current is compared to both the COMP voltage and the limit peak current cycle-by-cycle during an overload condition. When floating MODE, the inductor current is sampled by an external sense resistor between IN and SENSE. Under this configuration, sensed current is compared with COMP for lowside switch on/off control. However, the overload is protected by the average inductor current. When the sensed current signal exceeds 54mV, COMP is pulled low to regulate the boosted current. This causes the MP3428 to enter hiccup mode (after 1.1ms). The MP3428 re-starts after about 60ms in hiccup mode. If the sampled current signal rises to 100mV (within the 1.1ms blank time), www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 12 MP3428 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE immediately the mode. MP3428 operates in hiccup The MP3428 starts switching in internal currentsense mode after it detects 0V on MODE. In external current-sense mode, MP3428 detects MODE voltage and starts switching (after MODE is higher than Vin + 2V). In over-current or hiccup mode, MODE is pulled low. If the average current limit is triggered before switching, MP3428 may not start switching because MODE is regulated to low in an overload condition. If the peak-inductor current is higher than 6A, an external current-sensing resistor is recommended. Do NOT change the sensing configuration when MP3428 is in operation. Light-Load Operation To optimize efficiency at light load, MP3428 employs a pulse-skipping mechanism and foldback frequency. When the load becomes lighter, the COMP voltage decreases, causing the MP3428 to enter foldback operation (the lighter the load, the lower the frequency). However, if the load becomes exceedingly low, MP3428 enters PSM. PSM operation is optimized so that only one SW pulse is launched every burst cycle; therefore the output ripple is very low. Enable (EN) and Programmable UVLO EN enables and disables the MP3428. When applying voltage higher than the EN higher threshold (1V, typically), MP3428 starts up some of the internal circuits (micro-power mode). If EN voltage exceeds the turn-on threshold (1.33V), the MP3428 enables all functions and starts boost operation. Boost operation is disabled when EN voltage falls below its lower threshold (1.33V). To completely shut down the MP3428,