MP2619 The Future of Analog IC Technology 2A, 24V Input, 600kHz 2-3 Cell Switching Li-Ion Battery Charger With System Power Path Management DESCRIPTION FEATURES The MP2619 is a monolithic switching charger for 2-3 cell Li-Ion battery packs with a built in internal power MOSFET. It achieves up to 2A charge current with current mode control for fast loop response and easy compensation. The charge current can be programmed by sensing the current through an accurate sense resistor. MP2619 regulates the battery voltage and charge current using two control loops to realize high accuracy CC charge and CV charge. The system power path management function ensures continuous supply to the system by automatically selecting the input or the battery to power the system. Power path management separates charging current from system load. When the MP2619 realizes current sharing of the input current, charge current will drop down according to the increase of the system current. Fault condition protection includes cycle -by -cycle current limiting, and thermal shutdown. Other safety features include battery temperature monitoring, charge status indication and programmable timer to finish the charging cycle. The MP2619 is available in a 28-pin, 4mm x 5mm QFN package. MP2619 Rev. 1.01 5/28/2015 Charges 2-3 cell Li-Ion Battery Packs Wide Operating Input Range Up to 2A Programmable Charging Current Power Path Management with Current Sharing ±0.75% VBATT Accuracy 0.2Ω Internal Power MOSFET Switch Up to 90% Efficiency Fixed 600kHz Frequency Preconditioning for Fully Depleted Batteries Charging Operation Indicator Input Supply and Battery Fault Indicator Thermal Shutdown Cycle-by-Cycle Over Current Protection Battery Temperature Monitor and Protection APPLICATIONS Netbook PC Distributed Power Systems Chargers for 2-Cell or 3-Cell Batteries Pre-Regulator for Linear Regulators Li-Ion 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. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 1 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER TYPICAL APPLICATION M3 M1 RS2 VIN VSYS 20m C10 10µF R1 510 R2 510 RG1 PIN C2 4.7µF C7 0.1µF BST CELLS OUT1 VREF33 R3 10k L 4.7µF RG2 SW AIN C1 10µF 22uF M2 LED2 CHGOK ACOK VCC C3 10µF RG2 51 RG1 51 LED1 C8 MP2619 VREF25 RS1 110m D1 VBAT C9 22uF 2/3 cells battery RGS1 280 CSP BATT RGS2 280 NTC RNTC 10k EN Charge On/Off Power Path On/Off SHDN COMPV COMPI R4 2.7k C4 2.2nF MP2619 Rev. 1.01 5/28/2015 R5 750 GND TMR CTMR 0.1uF C5 2.2nF www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 2 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER ORDERING INFORMATION Part Number* Package Top Marking MP2619EV QFN-28 (4mmx5mm) MP2619 * For Tape & Reel, add suffix –Z (eg. MP2619EV–Z). For RoHS compliant packaging, add suffix –LF (eg. MP2619EV–LF–Z) PACKAGE REFERENCE TOP VIEW AIN PIN SW SW BST TMR 28 27 26 25 24 23 N/C 1 22 N/C NTC 2 21 GND ACOK 3 20 CSP CHGOK 4 19 BATT VREF33 5 18 COMPI N/C 6 17 CELLS EN 7 16 COMPV SHDN 8 15 VCC 9 10 11 12 RG1 N/C GND N/C 13 14 OUT1 RG2 ABSOLUTE MAXIMUM RATINGS (1) Recommended Operating Conditions Supply Voltage VIN ....................................... 26V VSW ....................................... –0.3V to VIN + 0.3V VBS ....................................................... VSW + 6V VCSP, VBATT, ..................................–0.3V to +18V All Other Pins .................................–0.3V to +6V (2) Continuous Power Dissipation (TA = +25°C) ............................................................. 3.1W Junction Temperature ...............................150C Lead Temperature ....................................260C Storage Temperature.............. –65C to +150C VCC, RG1, RG2 to GND..............–0.3V to +42V Max Differential Input Voltage, RG1 to RG2...5V Supply Voltage VIN ...........................5.5V to 24V Output Voltage VOUT .........................0.8V to 20V VCC, RG1, RG2 to GND .................2.5V to 40V Operating Junction Temp. (TJ). -40°C to +125°C MP2619 Rev. 1.01 5/28/2015 Thermal Resistance (4) θJA (3) θJC QFN-28 (4mmx5mm) ..............40 ....... 9 .... C/W 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 PD (MAX) = (TJ (MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will 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 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 3 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS VIN = 19V, TA = +25C, CELLS=0V, unless otherwise noted. Parameters Symbol Condition Terminal Battery Voltage CSP, BATT Current Switch On Resistance VBATT ICSP,IBATT RDS(ON) Switch Leakage CELLS=0V CELLS= Float Charging disabled Min Typ Max Units 8.337 12.505 8.4 12.6 1 0.2 8.463 12.695 V 0 1 EN = 4V, VSW = 0V CC Mode Peak Current Limit CC current Trickle charge current 4.1 Trickle Mode ICC RS1=100mΩ µA Ω A 2 1.8 A 2.2 A 10% Icc Trickle charge voltage threshold 3.0 V/Cell Trickle charge hysteresis 350 mV/Cell Termination current threshold Oscillator Frequency Fold-back Frequency Maximum Duty Cycle Maximum current Sense Voltage (CSP to BATT) Under Voltage Lockout Threshold Rising Under Voltage Lockout Threshold Hysteresis Open-drain sink current ITRICKLE 2.0 μA IBF fSW NTC Low-Temp Rising Threshold NTC High-Temp Falling Threshold Vin min head-room (reverse blocking) 10% VSENSE Vdrain=0.3V Stay at trickle charge, CTMR=0.1µF kHz 190 kHz % 170 200 230 mV 3 3.2 3.4 V 200 1000 mV 5 Vrechg RNTC=NCP18X103, 0°C RNTC=NCP18X103, 50°C Vin-Vbatt mA 30 min 4.0 100 V/cell mV/Cell %of VREF33 %of VREF33 mV 70.5 73.5 76.5 27.5 29.5 31.5 180 0.4 1.8 EN Input High Voltage MP2619 Rev. 1.01 5/28/2015 Icc 600 EN Input Low Voltage EN Input Current 15% 90 Dead-battery indicator Recharge threshold at Vbatt Recharge Hysteresis 5% CELLS=0V, VBATT=7V VBATT= 0V V V EN = 4V 4 EN = 0V 0.2 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. μA 4 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS (continued) VIN = 19V, TA = +25C, CELLS=0V, unless otherwise noted. Parameters Symbol Condition Min EN = 4V EN = 4V, Consider VREF33 pin output current. R3=10k,RNTC=10k Supply Current (Shutdown) Supply Current (Quiescent) Thermal Shutdown(5) VREF33 output voltage VREF33 load regulation Input Current Sense Section Supply Current OUT1 Input Offset Voltage OUT1 Current Accuracy No-Load OUT1 Error Low-Level OUT1 Error Shutdown Supply Current SHDN Threshold Voltage SHDN Hysteresis IAIN ICC(SHDN) VTH_SHUTD OWN 0.665 mA 150 3.3 30 VSENSE = 100mV VSENSE = 0V VSENSE = 5mV VSHDN = 3V 0.7 Units mA 2.0 ILOAD= 0A, VCC = 40V (Low High) Max 0.5 EN = 0V, CELLS=0V, VBATT=4.5V ILOAD=0 to 10mA ICC VOS1 IRG1/IGS Typ mA °C V mV 12 0.4 ±2 0.1 0.3 3 30 2 ±5 1 2 6 µA mV % µA µA µA 0.9 1.2 V 30 mV Notes: 5) Guaranteed by design. MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 5 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=110mΩ, RS2=20mΩ, Real Battery Load, TA=25ºC, unless otherwise noted. 2 Cells ICHG vs. VBATT Curve 2.5 2.5 8.2 8.1 1.5 8 7.9 1 7.8 IBATT 7.7 0.5 7.6 7.5 0 20 CHARGE CURRENT(A) 2 VBATT BATTERY CURRENT(A) VIN=12V 1 VIN=19V 0.5 0 0 2 6 8 100.0 1 VIN=24V VIN=19V 90.0 EFFICIENCY(%) EFFICIENCY(%) 1.5 0 11.8 IBATT VIN=19V 80.0 1 11.6 11.4 0.5 11.2 100.0 2 0.5 1.5 12 0 VIN=24V 70.0 VIN=15V 90.0 VIN=19V VIN=24V 80.0 70.0 3 Cells Battery 2 Cells Battery 0 2 4 6 8 10 12 14 60.0 0 0.4 B ATTER Y V OL TAGE(V ) 0.8 8.4 8.4 BATT VOLTAGE(V) 8.5 8.3 8.2 VIN (V) MP2619 Rev. 1.01 5/28/2015 0.4 28 1.2 1.6 2 Charge Current vs. Temperature 8.2 8 -20 0.8 ICHG (A) 8.3 2 Cells Battery 2 Cells Battery 23 0 2.2 8.1 8.1 18 2 BATT Float Voltage vs. Temperature 8.5 13 1.6 60.0 ICHG (A) BATT Float Voltage vs. VIN 88 1.2 0 150 50 100 TIMES(MIN) Effciency vs. ICHG VIN=15V VIN=12V 2 12.2 11 10 Effciency vs. ICHG 2.5 VBATT(V) 4 VBATT 12.4 BATTERY VOLTAGE(V) 3 Cells ICHG vs. VBATT Curve C HA R G E C U R R E NT(A ) VIN=24V 2 1.5 0 100 120 40 60 80 TIMES(MIN) 12.6 0 20 40 60 TEMPERATURE (OC) 80 C HA R G E C U R R E NT(A ) BATTERY VOLTAGE(V) 8.3 2.5 12.8 8.4 BATTERY VOLTAGE(V) 8.5 3 Cells Battery Charge Curve BATTERY CURRENT(A) 2 Cells Battery Charge Curve 2 1.8 1.6 1.4 2 Cells Battery 1.2 -20 0 20 40 TEMPERATURE www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 60 80 (OC) 6 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=110mΩ, RS2=20mΩ, Real Battery Load, TA=25ºC, unless otherwise noted. Efficiency vs. VIN Current Sharing NTC Control Window VBATT=7.4V, ICHG=2A 3 2.5 Low Temp Off 2.5 2 89 86 83 5 10 MP2619 Rev. 1.01 5/28/2015 15 VIN (V) 20 1.5 High Temp On 1 High Temp Off 25 0 1.5 1 0.5 0.5 2 Cells Battery 80 2 Low Temp On ICHG(A) 92 VNTC(V) EFFICIENCY (%) 95 0 8 12 16 20 VIN (V) 24 28 0 0.5 1 1.5 ISYS(A) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 2 2.5 7 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=110mΩ, RS2=20mΩ, Real Battery Load, TA=25ºC, unless otherwise noted. Trickle Charge CC Charge CV Charge 2 Cells, ICHG = 2A, VBATT = 5V 2 Cells, ICHG = 2A, VBATT = 7.4V 2 Cells, ICHG = 2A, VBATT = 8.4V VIN 10V/div. VBATT 5V/div. VSW 10V/div. VIN 10V/div. VIN 10V/div. VBATT 5V/div. VBATT 5V/div. VSW 10V/div. VSW 10V/div. IBATT 500mA/div. IBATT 200mA/div. IBATT 1A/div. Power On Power Off EN On 2 Cells, ICHG = 2A, VBATT = 8V 2 Cells, ICHG = 2A, VBATT = 8V 2 Cells, ICHG = 2A, VBATT = 8V VEN 5V/div. VIN 10V/div. VBATT 5V/div. VIN 10V/div. VSW 10V/div. VSW 10V/div. VSW 10V/div. IBATT 2A/div. IBATT 2A/div. VBATT 5V/div. VBATT 5V/div. IBATT 2A/div. EN Off NTC Control Timer Out 2 Cells, ICHG = 2A, VBATT = 8V 2 Cells, ICHG = 2A, VBATT = 7.4V 2 Cells, ICHG = 2A, VBATT = 7.4V VEN 5V/div. VBATT 5V/div. VNTC 2V/div. VBATT 5V/div. VSW 10V/div. VSW 10V/div. IBATT 2A/div. IBATT 2A/div. MP2619 Rev. 1.01 5/28/2015 VTMR 1V/div. VACOK 5V/div. VCHGOK 5V/div. ICHG 2A/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 8 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=110mΩ, RS2=20mΩ, Real Battery Load, TA=25ºC, unless otherwise noted. Power Path Power Path Management_Current Sharing Management_Steady State 2 Cells, ICHG = 2A, VBATT = 7.4V VIN 10V/div. VBATT 5V/div. ISYS 1A/div. IBATT 1A/div. 2 Cells, ICHG = 2A, VBATT = 8V, ISYS=0.8A VIN 10V/div. VIN 10V/div. VSW 10V/div. VBATT 5V/div. IBATT 1A/div. VSYS 5V/div. ISYS 500mA/div. IBATT 1A/div. VEN 5V/div. Power Path Management_EN On Power Path Management_EN Off 2-Cell, ICHG=2A, VBATT=7.6V, ISYS=1A, VIN=12V 2-Cell, ICHG=2A, VBATT=7.6V, ISYS=1A, VIN=12V VEN 5V/div. VIN 10V/div. VBATT 5V/div. IBATT 1A/div. VSYS 5V/div. MP2619 Rev. 1.01 5/28/2015 VSYS 5V/div. VBATT 5V/div. ISYS 1A/div. ICHG 1A/div. VSYS 10V/div. VBATT 2V/div. ISYS 500mA/div. ICHG 1A/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 9 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER PIN FUNCTIONS Pin # Name 1,6,10,12,22 NC No Connection Thermistor Input. Connect a resistor from this pin to the pin VREF33 and the Thermistor NTC from this pin to ground. Valid Input Supply Indicator. A logic LOW on this pin indicates the presence of a valid ACOK input supply. Charging Completion Indicator. A logic LOW indicates charging operation. The pin will CHGOK become an open drain once the charging is complete. Internal linear regulator 3.3V reference output. Bypass to GND with a 1μF ceramic VREF33 capacitor. 2 3 4 5 7 EN 8 SHDN 9 RG1 11, 21 Description On/Off Control Input. Shutdown control of current sense amplifier. Connect to ground for normal operation. Gain Resistor of current sense amplifier. Ground. This pin is the voltage reference for the regulated output voltage. For this GND, reason care must be taken in its layout. This node should be placed outside of the D1 to Exposed C1 ground path to prevent switching current spikes from inducing voltage noise into the Pad part. Connect exposed pad to ground plane for optional thermal performance. 13 OUT1 Output for Driving Resistor Load. 14 RG2 Gain Resistor of current sense amplifier. 15 VCC Power Input of current sense amplifier. 16 COMPV VLOOP Compensation. Decouple this pin with a capacitor and a resistor. 17 CELLS 18 COMPI ILOOP Compensation. Decouple this pin with a capacitor and a resistor. Command Input for the Number of Li-Ion Cells. Connect this pin to VREF33 or keep it float for 3-cell operation or ground the pin for 2-cell operation. 19 BATT Positive Battery Terminal. 20 CSP Battery Current Sense Positive Input. Connect a resistor RS1 between CSP and BATT. 23 TMR 24 BST 25, 26 SW Switch Output. 27 PIN Power Supply Voltage. The MP2619 operates from a +5.5V to +24V unregulated input. C1 is needed to prevent large voltage spikes from appearing at the input. 28 AIN Controller Supply Voltage. MP2619 Rev. 1.01 5/28/2015 Set time constant. 0.1uA charge and discharge the external cap. Connect TMR pin to GND to disable the internal timer. Bootstrap. This capacitor is needed to drive the power switch’s gate above the supply voltage. It is connected between SW and BST pins to form a floating supply across the power switch driver. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 10 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER OPERATION The MP2619 is a peak current mode controlled switching charger for use with Li-Ion batteries. Figure 1 shows the block diagram. At the beginning of a cycle, M1 is off. The COMP voltage is higher than the current sense result from amplifier A1’s output and the PWM comparator’s output is low. The rising edge of the 600 kHz CLK signal sets the RS Flip-Flop. Its output turns on M1 thus connecting the SW pin and inductor to the input supply. The increasing inductor current is sensed and amplified by the Current Sense Amplifier A1. Ramp compensation is summed to the output of A1 and compared to COMP by the PWM comparator. When the sum of A1’s output and the Slope Compensation signal exceeds the COMP voltage, the RS Flip-Flop is reset and M1 turns off. The external switching diode D1 then conducts the inductor current. If the sum of A1’s output and the Slope Compensation signal does not exceed the COMP voltage, then the falling edge of the CLK resets the Flip-Flop. The MP2619 have one internal linear regulators power internal circuit, VREF33. The output of 3.3V reference voltage can also power external circuitry as long as the maximum current (30mA) is not exceeded. A 1uF bypass capacitor is required from VREF33 to GND to ensure stability. Charge Cycle (Mode change: Trickle CC CV) The battery current is sensed via RS1 (Figure 1) and amplified by A2. The charge will start in “trickle charging mode” (10% of the RS1 programmed current ICC) until the battery voltage reaches 3.0V/cell. If the charge stays in the “trickle charging mode” till “timer out” condition triggered, and the charge is terminated. Otherwise, the output of A2 is then regulated to the level set by RS1. The charger is operating at “constant current charging mode.” The duty cycle of the switcher is determined by the COMPI voltage that is regulated by the amplifier GMI. regulate the COMP pin, and then the duty cycle. The charger will then operate in “constant voltage mode.” Automatic Recharge After the battery has completely recharged, the charger disables all blocks except the battery voltage monitor to limit leakage current. If the battery voltage falls below 4.0V/Cell, the chip will begin recharging using soft-start. The timer will then reset to avoid timer-related charging disruptions. Charger Status Indication MP2619 has two open-drain status outputs: CHGOK and ACOK . The ACOK pin pulls low when an input voltage is greater than battery voltage 300mV and over the under voltage lockout threshold. CHGOK is used to indicate the status of the charge cycle. Table 1 describes the status of the charge cycle based on the CHGOK and ACOK outputs. Table 1―Charging Status Indication ACOK CHGOK low low low high high high Charger Status In charging End of charge, NTC fault, timer out, thermal shutdown, EN disable PIN –VBATT<0.3V. AIN<UVLO, Timer Operation MP2619 uses internal timer to terminate the charge if the timer times out. The timer duration is programmed by an external capacitor at the TMR pin. The trickle mode charge time is: TTICKLE_TMR 30mins CTMR 0.1uF The total charge time is: TTOTAL_TMR 3hours CTMR 0.1uF When the battery voltage reaches the “constant voltage mode” threshold, the amplifier GMV will MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 11 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER When time-out occurs, charger is suspended. And only refresh the input power or EN signal or auto-recharge (The event that VBATT falls through 4V/cell) can restart the charge cycle. Negative Thermal Coefficient (NTC) Thermistor The MP2619 has a built-in NTC resistance window comparator, which allows MP2619 to sense the battery temperature via the thermistor packed internally in the battery pack to ensure a safe operating environment of the battery. A resistor with appropriate value should be connected from VREF33 to NTC pin and the thermistor is connected from NTC pin to GND. The voltage on NTC pin is determined by the resistor divider whose divide ratio depends on the battery temperature. When the voltage of pin NTC falls out of NTC window range, MP2619 will stop the charging. The charger will restart if the temperature goes back into NTC window range. MP2619 Rev. 1.01 5/28/2015 Power Path Management MP2619 can implement a switching charger circuit with power path management function, which realizes the current sharing of the charger and system load. In another word, MP2619 senses the system current and feeds it back, then reduces charge current according to the increase of the system current. However, after the charge current decrease to 0, the system current can only be limited by the adapter. The system current is satisfied first and always. It chooses the adapter as its power source when the adapter plugs in, and the battery is the backup power source when the adapter is removed. Figure 2 to 6 shows the charge profile, operation waveform and flow chart, respectively. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 12 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER BLOCK DIAGRAM VCC BIAS+ Enable RG1 RG2 SHDN Sense Amplifier OUT1 AIN PIN Current Sense A1 600kHz OSC PRE_REGS EN VREF IREF BST Regulator Current Limit Comparator 5 bit trim M1 S Q Drive R R 3 bit trim CTRL SW PWM Comparator L NC LDO VREF33 Charge Current Sense VBATT FB cells NTC A2 GMI GMV FB Charge Control Logic COMPI FB 4V Recharge Comparator 0.12V Charge Current Sense BF Comparator CELLS 2/3 cells battery 2.8V Max Trickle Time Max Charge Time RS1 TC/CC Charge Comparator CTRL Timer Max Reflesh Time BATT 0.12V or 1.2V COMP 1.2V TMR CSP x6 COMPV AIN ACOK ACOK CHGOK BATT+300mV GND Figure 1 — Functional Block Diagram MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 13 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER CHARGE PROFILE AND POWER PATH MANAGEMENT FUNCTION Figure 2 — Li-Ion Battery Charge Profile Power Path Management Current Sharing ISYS ICHG CC Charge When ICHG decreases to 0, the system current can only be limited by the adapter current capacity Figure 3 — Power Path Management Function- Current Sharing MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 14 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER OPERATION FLOW CHART Figure 4— Normal Charging Operation Flow Chart MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 15 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER OPERATION FLOW CHART (continued) Figure 5— Power Path Management Operation Flow Chart MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 16 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER OPERATION FLOW CHART (continued) Normal Operation Charge On, ACOK& CHGOK is low Charge Mode? VBATT=VBATT_FULL VBATT_TC<VBATT<VBATT_FULL VBATT<VBATT_TC C.V.C C.C.C T.C.C No No No Battery Full? ICHG<IBF VBATT>VBATT_FULL VBATT>VBATT_TC Yes Yes Yes Stop Charge. ACOK is low, CHGOK is high Yes No VBATT<VBATT_RECH? No No No o Timer Out ? NTC Fault? Tj>=150 C? Yes Yes Yes Charge Termination, ACOK& CHGOK are high Charge Suspend Charge Current Thermal Shutdown, ACOK& CHGOK are high No NTC OK? Tj<=130oC? Yes Yes Charger Recovery, Return to Normal Operation No Fault Protection Figure 6— Fault Protection Flow Chart MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 17 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER APPLICATION INFORMATION Setting the Charge Current 1. Standalone Switching Charger The charge current of MP2619 is set by the sense resistor RS1. The charge current programmable formula is as following: ICHG A 200mV RS1mΩ (1) 2. Switching Charger with Power Path Management Figure 7 shows the charge current sharing with the system current. RGS1/2 causes the charge current sense error as it changes the sense gain of A2, which can be calculated from: G A2 12.3 kΩ 2kΩ RGSkΩ (6) The charge current is set as: ICHG A 1230 G A2 RS1mΩ (7) Then the influence of RGS1 to the charge current is: ICHG A 2000 RGSΩ 10 RS1mΩ (8) To decrease the power loss of the sensing circuit, choose RS2 as small as possible, 20m is recommended. Too small RG1 results in too big current sense error of the system current, 50Ω is at least. Substitute these two values into equation (5), then the calibrated charge current set formula in power path application is got from equation (8): Figure 7— Charge current sharing with System current RGS1 RG1 (2) The voltage of OUT1 pin, VOUT1 can be calculated from: VOUT1 ISYS RS2 Gain ISYS RS2 RGS1 (3) RG1 When the system current increased ΔISYS, to satisfy the charge current decreased ΔISYS accordingly. The relationship should be: ΔIBAT ΔVOUT1 ΔISYS RS2 RGS1 RS1 RS1 RG1 (4) BecauseΔISYS=ΔIBATT, we can get: RS1 RGS1 RS2 RG1 MP2619 Rev. 1.01 5/28/2015 2000 2.5 RS1mΩ 10 RS1mΩ (9) Following table is the calculated RS1 and RGS1 value for setting different charge current. The gain of the system current is set as: Gain ICHG A Table2—ICHG Set in Power Path Application ICHG(A) 2 1.5 1 0.8 0.5 RGS(Ω) 280 402 665 909 2k RS1(mΩ) 110 160 260 360 800 If choose different RS2 and RG1, re-calculated from equation (5) and equation (8), then get the different equation (9) and the table. Also, any relationship between ΔISYS and ΔIBATT can be realized by re-calculate equation (4), (5) and (8). (5) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 18 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER Selecting the Inductor A 1µH to 10µH inductor is recommended for most applications. The inductance value can be derived from the following equation. L VOUT (VIN VOUT ) VIN IL fOSC To be simple in project, making R3=10k and R6 no connect will approximately meet the specification. (10) Where ΔIL is the inductor ripple current. VOUT is the 2/3 cell battery voltage. Choose inductor current to be approximately 30% if the maximum charge current, 2A. The maximum inductor peak current is: IL(MAX) ICHG IL 2 (11) Under light load conditions below 100mA, larger inductance is recommended for improved efficiency. For optimized efficiency, the inductor DC resistance is recommended to be less than 200mΩ. NTC Function As Figure 8 shows, the low temperature threshold and high temperature threshold are preset internally via a resistive divider, which are 73%·VREF33 and 30%·VREF33. For a given NTC thermistor, we can select appropriate R3 and R6 to set the NTC window. In detail, for the thermistor (NCP18XH103) noted in above electrical characteristic, At 0ºC, RNTC_Cold = 27.445k; At 50ºC, RNTC_Hot = 4.1601k. Assume that the NTC window is between 0ºC and 50ºC, the following equations could be derived: R6//R NTC_Cold R3 R6//R NTC_Cold R6//R NTC_Hot R3 R6//R NTC_Hot VTH_Low VREF33 VTH_High VREF33 73% (12) 30% (13) According to equation (12) and equation (13), we can find that R3 = 9.63k and R6 = 505k. MP2619 Rev. 1.01 5/28/2015 Figure 8— NTC function block Selecting the Input Capacitor The input capacitor reduces the surge current drawn from the input and also the switching noise from the device. The input capacitor impedance at the switching frequency should be less than the input source impedance to prevent high frequency switching current passing to the input. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 4.7µF capacitor is sufficient. Selecting the Output Capacitor The output capacitor keeps output voltage ripple small and ensures regulation loop stability. The output capacitor impedance should be low at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended. PC Board Layout The high frequency and high current paths (GND, IN and SW) should be placed to the device with short, direct and wide traces. The input capacitor needs to be as close as possible to the IN and GND pins. The external feedback resistors should be placed next to the FB pin. Keep the switching node SW short and away from the feedback network. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 19 MP2619 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER PACKAGE INFORMATION QFN28 (4mm x 5mm) 2.50 2.80 3.90 4.10 23 28 PIN 1 ID SEE DETAIL A PIN 1 ID MARKING 22 1 0.50 BSC PIN 1 ID INDEX AREA 3.50 3.80 4.90 5.10 0.18 0.30 8 15 0.35 0.45 TOP VIEW 14 9 BOTTOM VIEW PIN 1 ID OPTION A 0.30x45º TYP. PIN 1 ID OPTION B R0.25 TYP. 0.80 1.00 0.20 REF 0.00 0.05 DETAIL A SIDE VIEW 3.90 NOTE: 2.70 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX. 4) DRAWING CONFORMS TO JEDEC MO-220, VARIATION VHGD-3. 5) DRAWING IS NOT TO SCALE. 0.70 0.25 3.70 4.90 0.50 RECOMMENDED LAND PATTERN 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. MP2619 Rev. 1.01 5/28/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 20