MP2615CGQ-Z

MP2615C 2.1A, 1-Cell or 2-Cell Li-Ion Battery Charger in (3mmx3mm) Package DESCRIPTION FEATURES The MP2615C is a high-efficiency, switch-mode battery charger suitable for single-cell or dualcell Li-ion or Li-polymer applications. The device is capable of delivering 2.1A of charge current, which can be configured via an accurate current-sense resistor across the entire input range. • • • • • • • • The MP2615C regulates the charge current and full battery voltage using two control loops to achieve high-accuracy constant current (CC) charge and constant voltage (CV) charge. • • • • • • Constant-off-time (COT) control allows the device to operate up to 99% duty cycle when the battery voltage is close to the input voltage. This maintains a relatively high charging current. The battery temperature and charging statuses are always monitored during each charging cycle. Two status monitor output pins are provided to indicate the battery charging status and input power status. The MP2615C also features internal reverse blocking protection. • 4.75V to 18V Operating Input Voltage Up to 99% Duty Cycle Operation Up to 2.1A Configurable Charging Current ±0.75% Full Battery Voltage Accuracy 4.1V/Cell and 4.2V/Cell Selection for Full Battery Voltage Fully Integrated Power Switches Internal Loop Compensation No External Reverse Blocking Diode Required Preconditioning for Fully Depleted Battery Charging Operation Indicator Configurable Safety Timer Thermal Shutdown Protection Cycle-by-Cycle Over-Current Protection Battery Temperature Monitoring and Protection Available in a QFN-16 (3mmx3mm) Package APPLICATIONS • • • The MP2615C is available in a QFN-16 (3mmx3mm) package. Smartphones Portable Handheld Solutions Portable Media Players 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. TYPICAL APPLICATION L 5V to 18V Input RS1 SW VIN R2 C4 CHGOK BST ACOK CSP R1 C1 RNTC MP2615C VCC BATT NTC TMR EN SEL C2 R3 C3 1-Cell or 2-Cell Battery 100k ON OFF AGND PGND CELL CTMR MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 1 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER ORDERING INFORMATION Part Number* MP2615CGQ Package QFN-16 (3mmx3mm) Top Marking See Below MSL Rating 1 * For Tape & Reel, add suffix –Z (e.g. MP2615CGQ–Z). TOP MARKING BMR: Product code of MP2615CGQ Y: Year code LLLL: Lot number PACKAGE REFERENCE PGND BST TMR NTC ACOK TOP VIEW 16 15 14 13 12 VIN 2 10 CSP VCC 3 9 BATT CELL 4 5 6 7 8 AGND CHGOK N/C 11 EN 1 SEL SW QFN-16 (3mmx3mm) MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 2 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER PIN FUNCTIONS Pin # Name 1 2 SW VIN 3 VCC 4 CELL 5 SEL 6 EN 7 N/C 8 9 10 AGND BATT CSP 11 12 13 14 15 16 Description Switch output. Power supply voltage. Coarse regulator output. Internally generated 4.5V. Bypass VCC with a 1µF capacitor to AGND. VCC can be used as a low-side switch driver and a pull-up bias voltage NTC resistor divider. Do not connect any external load to VCC. Command input for the number of Li-ion cells. Connect this pin to VCC for single-cell applications. Float the CELL pin or short it to AGND for dual-cell applications. Input pin for setting terminal battery voltage. If SEL is pulled low or floating, VBATT is 4.2V/cell. If SEL is pulled high, VBATT is 4.1V/cell. On/off control input. This pin is pulled to GND with a 1MΩ internal resistor. It is recommended to connect a 100kΩ resistor in series with the EN pin. No connection. Leave this pin floating. Analog ground. Positive battery terminal. Battery current-sense positive input. Connect a resistor (RS1) between CSP and BATT. Charging completion indicator. When this pin goes logic low, the device is charging. The CHGOK pin becomes an open drain once the charge is completed or suspended. Valid input supply indicator. A logic low on this pin indicates the presence of a valid input ACOK power supply. Thermistor input. Connect a resistor from this pin to the VCC pin. Connect the thermistor NTC from this pin to ground. Internal safety timer control. Connect a capacitor from this node to AGND to set the TMR timer. Disable the timer by connecting this pin directly to AGND. Bootstrap pin. Use a capacitor to drive the power switch’s gate above the supply voltage. BST The capacitor should be connected between the SW and BST pins to form a floating supply across the power switch driver. PGND Power ground. MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 3 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER θJA θJC ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance (4) VSW ................................................-0.3V to +23V VIN, VACOK, VCHGOK..........................-0.3V to +23V VBATT, VCSP………………………….-0.3V to +12V VBST ...................................................... VSW + 6V All other pins ...................................-0.3V to +6V Junction temperature ................................150°C Lead temperature......................................260°C Continuous power dissipation (TA = 25°C) (2) ............................................................. 2.5W Operating temperature ............... -40°C to +85°C QFN-16 (3mmx3mm) .............. 50 ...... 12... °C/W ESD Ratings Charged device model (CDM)..................1250V Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature, TJ (MAX), the junction-toambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by P D (MAX) = (TJ (MAX) - TA) / θJA. Exceeding the maximum allowable power dissipation can cause excessive die temperature, and the regulator may go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. Recommended Operating Conditions (3) VIN…………………………………… 4.75V to 18V VBATT ................................................... 2V to 8.4V Operating junction temp (TJ) ...... -40°C to +85°C MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 4 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS VIN = 12V, VCELL = 0V, VSEL = 0V, C1 = 22µF, C2 = 22µF, TA = 25°C, unless otherwise noted. Parameter Symbol Condition Min Typ Max Units VCELL = 4V VCELL = 0V 4.5 8.75 5 12 18 18 V 3.55 3.75 3.95 V Input Voltage and Current Input voltage Under-voltage lockout rising threshold Under-voltage lockout threshold hysteresis Supply current Power MOSFET High-side switch on resistance Low-side switch on resistance VIN VUVLO 225 ISHDN EN = 4V, shutdown current 0.27 IQ EN = 0V, quiescent current 1.1 110 mΩ RL_DS(ON) 110 mΩ EN = 4V, VSW = 0V Frequency and Time Parameter Switching frequency fSW Foldback frequency Minimum off time (5) tOFF Charging Parameter VBATT = 7.5V VBATT = 0V VBATT = 9V VBATT_FULL Battery over-voltage threshold VBOVP Recharge threshold at VBATT VRECH VSEL = 0V VSEL = 4V VCELL = 0V, VSEL = 0V VCELL = 0V, VSEL = 4V VCELL = 4V, VSEL = 0V VCELL = 4V, VSEL = 4V VSEL = 0V VSEL = 4V 0 4.168 4.069 8.34 8.14 4.17 4.07 4.2 4.1 8.71 8.51 4.36 4.26 4.0 3.9 VTC VSEL = 0V VSEL = 4V Peak current limit ICC ITC Constant current charge Trickle RS1 = 25mΩ IBF VIN - VBATT μA kHz kHz ns 4.231 4.131 9.08 8.88 4.54 4.44 150 V/cell mV/cell 3 2.91 225 Trickle charge hysteresis CC current Trickle charge current Termination current threshold VIN minimum headroom (reverse blocking) 1 760 160 200 Recharge hysteresis Trickle-charge voltage threshold mA RH_DS(ON) Measured from VIN to SW Switch leakage Terminal battery voltage mV V/cell mV/Cell 3.2 A 1.9 5% 2.2 2.1 10% 2.3 15% A ICC 5% 10% 15% ICC 300 MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. mV 5 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS (continued) VIN = 12V, VCELL = 0V, VSEL = 0V, C1 = 22µF, C2 = 22µF, TA = 25°C, unless otherwise noted. Parameter Maximum current-sense voltage (CSP to BATT) Symbol CSP, BATT current ICSP, IBATT ACOK/CHGOK open-drain sink current VCC Regulator Output VCC output voltage VCC load regulation EN Control Condition VSENSE Typ Max Units 47.5 52.5 57.5 mV 3 µA Charging disabled VDRAIN = 0.3V VCC ∆VCC Min 5 4.2 mA 4.5 ILOAD = 0 to 10mA EN input low voltage Logic CELL input low voltage CELL input high voltage SEL input low voltage SEL input high voltage Timer Protection Trickle charge time CC/CV charge time NTC Protection NTC cold temp rising threshold NTC cold temp rising threshold hysteresis NTC hot temp falling threshold NTC hot temp falling threshold hysteresis Thermal Protection Thermal shutdown (5) Thermal shutdown hysteresis (5) V mV 0.4 V 1.9 EN input high voltage EN input current 4.75 10 IEN EN = 4V 4 EN = 0V 0.2 VL VH VL VH 1.8 0.4 1.8 30 CTMR = 0.47μF 73.3 74.6 RNTC = NCP18X103, 0°C 2 28 VHOT V V V V min 165 72 VCOLD μA 0.4 tTRICKLE_TMR CTMR = 0.47μF tTOTAL_TMR V 29.3 30.6 % of VCC RNTC = NCP18X103, 50°C 2 TSHDN 150 °C 20 °C Reverse Leakage Blocking Battery reverse leakage current ILEAKAGE VCELL = 0V VCELL = 4V 3 0.5 µA µA Notes: 5) Guaranteed by design. MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 6 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS VIN = 12V, C1 = C2 = 22μF, SEL = float/high, CELL = float/high, RS1 = 25mΩ, unless otherwise noted. Battery-Full Voltage vs. Battery-Full Voltage vs. Temperature Temperature 2-cell 1-cell 8.45 BATTERY-FULL VOLTAGE (V) BATTERY-FULL VOLTAGE (V) 4.22 4.2 4.18 4.16 VBATT_FULL=4.1V 4.14 VBATT_FULL=4.2V 4.12 4.1 4.08 4.06 -50 0 50 100 8.4 8.35 8.3 VBATT_FULL=8.2V 8.25 VBATT_FULL=8.4V 8.2 8.15 8.1 -50 150 50 100 150 TEMPERATURE (°C) TEMPERATURE (°C) Constant Charge Current vs. Temperature Trickle Charge Current vs. Temperature RS1 = 25mΩ RS1 = 25mΩ 2.19 TRICKLE CHARGE CURRENT (mA) 250 2.17 CONSTANT CHARGE CURRENT (A) 0 240 2.15 230 2.13 2.11 220 2.09 210 2.07 200 2.05 -50 0 50 100 -50 150 0 50 100 150 TEMPERATURE (°C) TEMPERATURE (°C) Charge-Full Current vs. Temperature VCC Output Voltage vs. Temperature 4.55 VCC OUTPUT VOLTAGE (V) CHARGE-FULL CURRENT (mA) RS1 = 25mΩ 250 240 230 220 210 200 4.5 4.45 4.4 4.35 4.3 -50 0 50 100 TEMPERATURE (°C) 150 -50 0 50 100 TEMPERATURE (°C) MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 150 7 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 12V, C1 = C2 = 22μF, SEL = float/high, CELL = float/high, RS1 = 25mΩ, unless otherwise noted. Auto-Recharge Threshold Voltage vs. Temperature Auto-Recharge Threshold Voltage vs. Temperature 2-cell 4 8 3.98 7.95 AUTO-RECHARGE THRESHOLD (V) AUTO-RECHARGE THRESHOLD (V) 1-cell 3.96 3.94 7.9 VBATT_FULL=8.2V 7.85 3.92 VBATT_FULL=4.1V 3.9 VBATT_FULL=4.2V VBATT_FULL=8.4V 7.8 7.75 3.88 7.7 3.86 3.84 7.65 -50 0 50 100 TEMPERATURE (°C) 150 -50 0 50 100 150 TEMPERATURE (°C) MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 8 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V/9V, C1 = C2 = 22µF, SEL = float/high, CELL = float/high, L = 6.8µH, RS1 = 25mΩ, battery simulator, TA = 25°C, unless otherwise noted. Battery Charge Curve Auto-Recharge VIN = 5V, 1-cell, VBATTREG = 4.2V VIN = 5V, 1-cell, VBATTREG = 4.2V CH1: VIN CH1: VIN CH2: VBATT CH2: VBATT CH4: IBATT CH4: IBATT CH3: VSW CH3: VSW Trickle Charge Steady State Trickle Charge Steady State VIN = 5V, 1-cell, VBATT = 1.9V VIN = 9V, 2-cell, VBATT = 5.2V CH2: VBATT CH1: VIN CH1: VIN CH2: VBATT CH4: IL CH4: IL CH3: VSW CH3: VSW CC Charge Steady State CC Charge Steady State (COT) VIN = 5V, 1-cell, VBATT = 3.6V VIN = 5V, 1-cell, VBATT = 4V CH1: VIN CH1: VIN CH2: VBATT CH2: VBATT CH4: IL CH4: IL CH3: VSW CH3: VSW MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 9 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V/9V, C1 = C2 = 22µF, SEL = float/high, CELL = float/high, L = 6.8µH, RS1 = 25mΩ, battery simulator, TA = 25°C, unless otherwise noted. CC Charge Steady State CC Charge Steady State (COT) VIN = 9V, 2-cell, VBATT = 6.5V VIN = 9V, 2-cell, VBATT = 7.5V CH1: VIN CH1: VIN CH2: VBATT CH2: VBATT CH4: IL CH4: IL CH3: VSW CH3: VSW CV Charge Steady State CV Charge Steady State VIN = 5V, 1-cell, VBATT = 4.17V VIN = 9V, 2-cell, VBATT = 8.35V CH1: VIN CH1: VIN CH2: VBATT CH2: VBATT CH4: IL CH4: IL CH3: VSW CH3: VSW Start-Up, CC Charge Mode Shutdown, CC Charge Mode VIN = 9V, 2-cell, VBATT = 7V VIN = 9V, 2-cell, VBATT = 7V CH2: VBATT CH2: VBATT CH1: VIN CH1: VIN CH4: IBATT CH4: IBATT CH3: VSW CH3: VSW MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 10 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V/9V, C1 = C2 = 22µF, SEL = float/high, CELL = float/high, L = 6.8µH, RS1 = 25mΩ, battery simulator, TA = 25°C, unless otherwise noted. VIN Hot Insertion, CC Charge Mode VIN Removal, CC Charge Mode VIN = 9V, 2-cell, VBATT = 7V VIN = 9V, 2-cell, VBATT = 7V CH2: VBATT CH1: VIN CH4: IBATT CH1: VIN CH4: IBATT CH2: VBATT CH3: VSW CH3: VSW EN On/Off NTC Fault Control VIN = 5V, 1-cell, VBATT = 3.6V VIN = 9V, 2-cell, VBATT = 7V CH1: VEN CH1: VNTC CH2: VBATT CH4: IBATT CH4: IBATT CH2: VBATT CH3: VSW CH3: VSW Timeout Charge-Full Indication VIN = 9V, 2-cell, VBATT = 7V, ICC = 2A, CTMR = 470pF VIN = 5V, 1-cell, VBATT = 3.6V CH1: VIN CH1: VTMR CH4: IBATT CH2: VBATT CH4: IBATT CH3: VSW CH2: VCHGOK CH3: VACOK MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 11 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER FUNCTIONAL BLOCK DIAGRAM VIN Current Sense IHS EN PRE_REGS A1 BST OSC Regulator CTRL VREF 5-Bit Trim M1 Current Limit Comparator S Q Drive R R M2 SW LDO COMP VCC PWM Comparator Charge Current Sense NTC FB COMPV GMI GMV Cells COMPI 1.23V L M3 BATT A2 0.123V or 1.23V CSP BATT RS1 1-Cell or 2Cell Battery OVP CTRL ICHG TMR SEL Timer TC/CC Charge Comparator OVP Comparator OVP 1.23V VIN ACOK Comparator Charge Control Logic Recharge Comparator BF Comparator VBATT + 0.2V ACOK CELLS FB 0.879V FB 1.171V ICHG 0.123V CHGOK AGND PGND Figure 1: Functional Block Diagram MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 12 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER OPERATION The MP2615C is a peak current mode control switching charger for single-cell or dual-cell Li-ion and Li-polymer batteries. The MP2615C integrates both the high-side and low-side MOSFETs of the synchronous buck converter to provide high efficiency and reduce PCB size. Charge Cycle (Mode Change: TC to CC to CV) The MP2615C regulates the charge current (ICHG) and battery voltage (VBATT) using two control loops to achieve highly accurate constant current (CC) charge and constant voltage (CV) charge. If VBATT is below VTC, the MP2615C remains in trickle charge mode, and the output of the charge current loop (COMPI) dominates the control (see Figure 2). The battery is charged by a trickle charge current (ITC) until the battery voltage reaches VTC. If the charger remains in trickle charge mode until the trickle charge timer is triggered, charging is terminated. The MP2615C enters CC charge mode once the battery voltage exceeds VTC. In this mode, the charge current increases from ITC to ICC to fast charge the battery. If the battery voltage exceeds the battery-full voltage (VBATT_FULL), the charger enters CV mode. In CV mode, the battery voltage is regulated at VBATT_FULL, and the charge current falls naturally due to the existing equivalent internal resistance of the battery. Figure 4 shows an operation flowchart. CV Charge Threshold AutoRecharge Threshold CC Charge Current ICHG VBATT CC Charge Threshold IBF Trickle Charge CC Charge CV Charge Charge Full TC Charge Current AutoRecharge Figure 2: Li-Ion Battery Charge Profile Charge Full Termination and Auto-Recharge If the charge current drops below the termination threshold (IBF) during the CV charge phase, the charger stops charging and the CHGOK pin becomes an open drain. The timer resets and turns off. Once the battery voltage drops below the recharge threshold (VRECH) (4.0V/cell while the SEL pin is connected to AGND), recharging automatically begins and the timer restarts a new charge cycle. Constant-Off-Time (COT) Charge Mode The MP2615C uses the floating ground method to drive the buck converter’s high-side MOSFET (HS-FET). While the HS-FET is off, the BST capacitor is recharged, and the voltage across the capacitor is used as the HS-FET’s gate driver. Thus a minimum off time of 200ns is required to maintain sufficient voltage at the BST capacitor. When the 200ns minimum off time is achieved due to a large duty cycle, the MP2615C enters constant-off-time (COT) charge mode. In this mode, the switching frequency is slightly reduced to achieve a 99% duty cycle. Charge Status Indication The MP2615C has two open-drain status outputs: the CHGOK and ACOK pins. The ACOK pin goes low when the input voltage exceeds the battery voltage and the undervoltage lockout (UVLO) threshold by 300mV. The CHGOK pin indicates the status of the charge cycle. Table 1 lists the operation for both CHGOK and MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 13 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER The trickle mode charge time can be estimated with Equation (2): ACOK according to the charger status. Table 1: Charging Status Indication ACOK Low Low High impedance CHGOK Low t TRICKLE_TMR (minutes) = 62.8  CTMR (F) Charger Status High impedance Charging • End of charging • NTC fault has occurred • Timer ran out High impedance • • • • If CTMR is 0.47µF, the trickle charge time is about 30 minutes. The CC/CV mode charge time can be calculated with Equation (3): t TOTAL_TMR (hours) = 6.28  CTMR (F) EN disabled Thermal shutdown VIN absent VIN - VBATT < 0.3V (1) This timer limits the maximum trickle charge time to 8192 internal oscillating periods. If the charger remains in trickle charge mode for longer than the maximum oscillating periods, charging is terminated and CHGOK becomes an open drain to indicate a timeout fault. If the charge cycle successfully completes trickle charge within the allowed time limit, it enters CC charge mode and the timer continues to count the oscillating periods. When the battery is fully charged, the timer turns off and clears the counter, waiting for the auto-recharge to restart. If the charge time during CC/CV mode exceeds 49152 oscillating periods, and the battery-full condition has not been met, charging is terminated and a timeout fault is indicated by floating the CHGOK pin. The charger can exit the timeout fault state (and restart the on-chip safety timer) when one of the following conditions occurs: • • • (3) In this case, if CTMR is 0.47µF, the CC/CV charge time is 2.95 hours. Safety Timer Operation The MP2615C has an internal safety timer to terminate charging during timeout. The capacitor (CTMR) connected between the TMR pin and GND is used to set the internal oscillator period, calculated with Equation (1): tP (seconds) = 0.46  CTMR (F) (2) The battery voltage falls below the autorecharge threshold (VRECH) A power-on reset (POR) event occurs The EN pin is toggled The timer can be disabled by pulling the TMR pin to AGND. Negative Thermal Coefficient (NTC) Thermistor The NTC pin allows the MP2615C to sense the battery temperature using the negative thermal coefficient (NTC) resistor in the battery pack. This ensures a safe operating environment for the battery. A resistor with an appropriate value should be connected from the VCC pin to the NTC pin, and the thermistor should be connected from the NTC pin to AGND. The voltage on the NTC pin is determined by the resistor divider, which has a divide ratio that depends on the battery temperature. When the voltage at the NTC pin falls out of the NTC window range, charging pauses until the battery temperature returns to within the normal operating range. As a result, the MP2615C stops charging and reports this condition to the status pins. Charging automatically resumes after the temperature returns to within a safe range. Short-Circuit Protection The MP2615C has an internal comparator to check for battery short-circuit conditions. If VBATT falls below 2V, the device detects a battery short status, and the cycle-by-cycle peak current limit falls to about 2.2A to limit the current spike during the battery short transition. The switching frequency also folds back to minimize the power loss. Thermal Shutdown Protection To prevent the chip from overheating while it charges, the MP2615C monitors the junction temperature (TJ) of the die. If TJ reaches the thermal shutdown threshold (TSHTDWN) of 150°C, the charger converter turns off. Once TJ falls below 130°C, charging resumes. MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 14 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER INPUT POWER START-UP TIMING FLOW Figure 3: Input Power Start-Up Timing Diagram MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 15 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER OPERATION FLOWCHART Figure 4: Operation Flowchart MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 16 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER APPLICATION INFORMATION COMPONENT SELECTION Charge Current Setting The MP2615C’s constant charge current (ICC) can be set via the sense resistor (RS1) (see the Typical Application Circuit section on page 18). Calculate the constant current (CC) charge with Equation (4): ICC = 52.5mV (A) RS1(m) (4) If VBATT = 6V and fSW = 760kHz, the calculated inductance is 6.6µH. The inductor saturation current must exceed 2.6A and have some tolerance. To optimize efficiency, choose an inductor with a DC resistance below 50mΩ. NTC Resistor Divider Selection Figure 5 shows how an internal resistor divider sets the cold temperature threshold and hot temperature threshold at 73.3% of VCC and 31.1% of VCC, respectively. If ICC is 2.1A, choose RS1 to be 25mΩ. The trickle charge current estimated with Equation (5): (ITC) ITC = 0.10  ICC can be (5) Selecting the Inductor To select the optimal inductor, a tradeoff should be made between cost, size, and efficiency. An inductor with a lower-value inductance has the benefit of a smaller size, but also has higher ripple currents, magnetic hysteretic losses, and output capacitance. Conversely, a higher-value inductor lowers the ripple current and allows for the use of smaller output filter capacitors, but it also results in higher inductor DC resistance (DCR) loss. Based on practical experience, the inductor ripple current should not exceed 30% of the maximum charge current under the worst-case conditions. For the MP2615C, with a typical 12V input voltage to charge a 2-cell battery, the maximum inductor current ripple occurs at the corner point between trickle charge and CC charge (VBATT = 6V). The inductance can be calculated with Equation (6): L= VIN -VBATT VBATT ΔIL_MAX VIN  fSW (6) The thermistor (NCP18XH103) in Figure 5 has the following electrical characteristics: • • At 0°C, RNTC_COLD = 27.445kΩ At 50°C, RNTC_HOT = 4.1601kΩ For a given NTC thermistor, select values for RT1 and RT2 to set the NTC window. Assuming that the NTC window is between 0°C and 50°C, the cold and hot thresholds can be calculated with Equation (8) and Equation (9), respectively: RT2 //RNTC_COLD RT1 + RT2 //RNTC_COLD RT2 //RNTC_HOT RT1 + RT2 //RNTC_HOT Where VIN is the input voltage, VBATT is the CC charge threshold, and fSW is the switching frequency. ∆IL_MAX is the maximum inductor ripple current, which is usually 30% of the CC charge current, calculated with Equation (7): ΔIL_MAX = 0.30  ICC Figure 5: NTC Functional Block (7) = VCOLD = 73.3% (8) = VHOT = 31.1% (9) The required battery temperature range can be paired with Equation (8) and Equation (9) to calculate RT1 and RT2. Selecting the Input Capacitor The input capacitors (C1) from the typical application circuit absorb the maximum ripple current from the buck converter, which can be MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 17 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER estimated with Equation (10): IRMS_MAX = ICC VTC  (VIN_MAX − VTC ) VIN_MAX 1CO = (10) 8  fsW 2  L  RO_MAX = 21.3F (12) In this case, choose a 22µF ceramic capacitor. If ICC = 2A, VTC = 6V, and VIN_MAX = 18V, the maximum ripple current is 1A. Select the input capacitors so that the temperature rise due to the ripple current does not exceed 10°C. It is recommended to use ceramic capacitors with X5R or X7R dielectrics because of their low ESR and small temperature coefficients. For most applications, use a 22µF capacitor. PCB Layout Guidelines Proper PCB layout is important to meet specified noise, efficiency and stability requirements. For the best results, refer to Figure 6 and follow the guidelines below: 1. Route the power stage adjacent to the grounds. Selecting the Output Capacitor The output capacitor (C2) is in parallel with the battery. C2 absorbs the high-frequency switching ripple current and smooths the output voltage. Its impedance must be below the battery’s to ensure it absorbs the ripple current. Use a ceramic capacitor because it has a lower ESR and smaller size. The output voltage ripple can be calculated with Equation (11): VO VO VIN ΔRO = = VO 8  CO  fSW 2  L VTC VIN_MAX 2. Aim to minimize the high-side switching node (SW, inductor) trace lengths in the high-current paths and the current-sense resistor trace. 3. Keep the switching node short, and route it away from the feedback network. 4. Connect the charge current-sense resistor to CSP (pin 10) and BATT (pin 9). Minimize the length and area of this circuit loop. 1- 5. Place the input capacitor as close as possible to the VIN and PGND pins. (11) 6. Place the output inductor as close as possible to the IC, and connect the output capacitor between the inductor and PGND of the IC. This minimizes the current path loop area from the SW pin through the LC filter and back to the PGND pin. To guarantee u0.5% battery-full voltage accuracy, the maximum output voltage ripple should not exceed 0.5% (e.g. 0.1%). The maximum output voltage ripple occurs at the minimum battery voltage of the CC charge and the maximum input voltage. 7. Connect AGND and PGND at a single point. If VIN_MAX = 18V, VCC_MIN = VTC = 6V, L = 6.8µH, fSW = 760kHz, and ∆RO_MAX = 0.1%, the output capacitor can be calculated with Equation (12): PGND BST TMR NTC ACOK BATT GND GND VIN CHGOK CSP BATT CELL SEL EN NC AGND SW VIN VCC Figure 6: Recommended PCB Layout MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 18 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER TYPICAL APPLICATION CIRCUIT L VIN 1kΩ 6.8µH SW VIN R2 C4 BST CHGOK RS1 25mΩ 100nF 1kΩ R1 CSP ACOK R3 C1 22µF RNTC C3 1µF VCC BATT NTC TMR EN SEL 10kΩ 10kΩ C2 MP2615C 22µF 2-Cell Battery R4 100kΩ ON OFF AGND CTMR 1µF PGND CELL Figure 7: Typical Application Circuit to Charge a 2-Cell Battery with 12V VIN MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 19 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER PACKAGEPACKAGE INFORMATION OUTLINE DRAWING FOR 16L FCQFN (3X3MM) MF-PO-D-0157 revision 0.0 QFN-16 (3mmx3mm) PIN 1 ID MARKING PIN 1 ID 0.10x45° TYP. PIN 1 ID INDEX AREA BOTTOM VIEW TOP VIEW SIDE VIEW NOTE: 0.10x45° 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETERS MAX. 4) JEDEC REFERENCE IS MO-220. 5) DRAWING IS NOT TO SCALE. RECOMMENDED LAND PATTERN MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 20 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER CARRIER INFORMATION Pin1 1 1 ABCD 1 1 ABCD ABCD ABCD Feed Direction Part Number Package Description Quantity/ Reel Quantity/ Tube Quantity/ Tray Reel Diameter Carrier Tape Width Carrier Tape Pitch MP2615CGQ–Z QFN-16 (3mmx3mm) 5000 N/A N/A 13in 12mm 8mm MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 21 MP2615C – 2.1A, 1-CELL OR 2-CELL LI-ION BATTERY CHARGER REVISION HISTORY Revision # 1.0 Revision Date 9/11/2020 1.1 6/15/2023 Description Initial Release Updated the maximum current-sense voltage (CSP to BATT) to 47.5 (min), 52.5 (typ), 57.5 (max); updated the EN input high voltage to 1.9 (min); updated the NTC hot temp falling threshold to 28 (min), 29.3 (typ), 30.6 (max) Pages Updated 6 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. MP2615C Rev. 1.1 www.MonolithicPower.com 6/15/2023 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2023 MPS. All Rights Reserved. 22