MP26124GR-Z

MP26124 24V Input, 2A, 600kHz, 4S Cell Switching Li-Ion Battery Charger DESCRIPTION FEATURES The MP26124 is a monolithic, DC/DC, stepdown, switching charger for 4-series cell Li-ion battery packs. The MP26124 has an integrated high-side power MOSFET that can output a charge current up to 2A and also has peakcurrent-mode control for fast loop response and easy compensation.             The MP26124 uses a sense resistor to control a programmable charge current and regulates the charge current and charge voltage accurately using two control loops. The MP26124 has multiple fault condition protections including cycle-by-cycle current limiting and thermal shutdown. Other safety features include battery temperature monitoring and protection, charge status indication, and a programmable timer to stop the charging cycle when the timer expires. Charge 4S Cell Li-Ion Battery Packs Up to 24V Operation Voltage Programmable Charging Current up to 2A ±0.75% VBATT Accuracy 0.2Ω Integrated Power MOSFET Up to 90% Efficiency Fixed 600kHz Frequency Preconditioning for Fully Depleted Batteries Charging Status Indicator Input Supply Fault Indicator Thermal Shutdown Cycle-by-Cycle Over-Current Protection (OCP) Battery Temperature Monitor and Protection Available in a QFN-16 (4mmx4mm) Package   APPLICATIONS    The MP26124 requires a minimal number of readily available external components and is available in a QFN-16 (4mmx4mm) package. Clean Robots Drones Chargers for 4S Cell Li-Ion Batteries 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” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION D1 VIN C1 4.7μF 18V to 24V VIN C3 1μF SW VREF33 R1 R2 VCC BST CHGOK MP26124 R3 10k Ω RNTC 10kΩ BATT SGND COMPI ONOFF EN COMPV GND TMR R5 200m Ω D2 C2 10μF 4S Battery 750 Ω R42.5kΩ C6 0.1μF MP26124 Rev. 1.0 10/10/2017 RS1 10μH CSP ACOK NTC C7 0.1μF L C4 2.2nF C5 4.7nF www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 1 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER ORDERING INFORMATION Part Number* MP26124GR Package QFN-16 (4mmx4mm) Top Marking See Below *For Tape & Reel, add suffix –Z (e.g. MP26124GR–Z) TOP MARKING MP: MPS prefix Y: Year code WW: Week code M26124: Product code of MP26124GR LLLLLL: Lot number PACKAGE REFERENCE QFN-16 (4mmx4mm) MP26124 Rev. 1.0 10/10/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 2 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance (4) Supply voltage (VCC, VIN) ..........................28V VSW ................................... -0.3V to (VIN + 0.3V) VBST .....................................................VSW + 6V VCSP, VBATT ................................... -0.3V to +20V VACOK, VCHGOK ............................... -0.3V to +28V All other pins .................................. -0.3V to +6V Continuous power dissipation (TA = 25°C) (2) ..................................................................2.7W Junction temperature ............................... 150°C Lead temperature .................................... 260°C Storage temperature ................ -65°C to +150°C QFN-16 (4mmx4mm) ............ 46 ....... 10 ... °C/W Recommended Operating Conditions (3) θJA θJC 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 produces an excessive die temperature, causing the regulator to 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 board. Supply voltage (VIN) ........................ 18V to 24V Maximum junction temp. (TJ) ................... 125°C MP26124 Rev. 1.0 10/10/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 3 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS VIN = 24V, TA = 25°C, unless otherwise noted. Parameters Symbol Terminal battery voltage CSP, BATT current Switch on resistance VBATT ICSP, IBATT RDS(ON) Switch leakage Peak current limit CC current Condition Min Typ Max Units 16.67 16.93 Charging disabled 16.8 1 200 V µA mΩ EN = 4V, VSW = 0V 0 1 μA CC (5) 4.1 A TRICKLE 2 A ICC RS1 = 100mΩ 1900 2100 2300 mA Trickle charge current ITRICKLE 10% ICC Trickle charge voltage threshold VTC 12.0 V 1400 mV Trickle charge hysteresis Termination current threshold Oscillator frequency Fold-back frequency Maximum duty cycle Maximum current sense voltage (CSP to BATT) Minimum on time (5) IBF fSW 5% VBATT = 14V VBATT = 0V VSENSE 180 tON Dead battery indicator In trickle mode, CTMR = 0.1μF MP26124 Rev. 1.0 10/10/2017 ICC kHz kHz % 210 240 mV 100 VDRAIN = 0.3V NTC low-temp rising threshold NTC high-temp falling threshold VIN min head room (reverse blocking) 15% 90 Under-voltage lockout threshold rising Under-voltage lockout threshold hysteresis Open-drain sink current Recharge threshold at VBATT Recharge hysteresis 10% 600 190 3.05 3.25 ns 3.45 300 mV 5 VRECHG V mA 30 min 16.0 400 V mV VTL As a percentage of VREF33 64.2 65.2 66.2 % VTH As a percentage of VREF33 34 35 36 % VIN - VBATT 250 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. mV 4 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER ELECTRICAL CHARACTERISTICS (continued) VIN = 24V, TA = 25°C, unless otherwise noted. Parameters Symbol Condition Min Typ EN input low voltage 0.4 V V EN = 4V 4 EN = 0V 0.2 EN = 4V 0.5 mA 0.665 mA Supply current (shutdown) EN = 4V, considering the VREF33 output current, R3 = 10kΩ, RNTC = 10kΩ Supply current (quiescent) EN = 0V (5) Thermal shutdown VREF33 output voltage VREF33 load regulation Units 1.8 EN input high voltage EN input current Max ILOAD = 0 to 10mA μA 2.0 mA 150 3.3 °C V 35 mV NOTE: 5) Guaranteed by design. MP26124 Rev. 1.0 10/10/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 5 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS VIN = 18V, C1 = 4.7μF, C2 = 22μF, L = 10μH, RS1 = 200mΩ, real/simulation battery load, TA = 25°C, unless otherwise noted. 4-Cell Charge Current vs. Battery Voltage Efficiency vs. ICHG 4 cells, VBATT = 16.4V Battery simulator 100% 1 95% 0.8 EFFICIENCY CHARGE CURRENT(A) 1.2 0.6 0.4 90% 85% 0.2 80% 0 0 5 10 15 0 20 0.2 0.4 0.6 0.8 1 ICHG(A) BATTERY VOLTAGE(V) Efficiency vs. VIN NTC Control Window 4 cells, VBATT = 14.8V 2.5 96% 94% VNTC(V) Efficiency 2 92% 1.5 1 High Temp On High Temp Off 0.5 Low Temp On Low Temp Off 90% 18 20 22 0 24 18 VIN(V) 20 22 24 VIN(V) Battery Leakage Current vs. VBATT BATT Full Voltage vs. VIN 16.8 10 8 VBATT(V) IBATT(μA) 16.7 6 4 2 16.6 16.5 0 0 4 8 12 VBATT(V) MP26124 Rev. 1.0 10/10/2017 16 20 18 20 22 24 VIN(V) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 6 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 18V, C1 = 4.7μF, C2 = 22μF, L = 10μH, RS1 = 200mΩ, real/simulation battery load, TA = 25°C, unless otherwise noted. Terminal Battery Voltage vs. Temperature Charge Current vs. Temperature RS1 = 100mΩ, BATT = 14V 2300.0 2100.0 16.8 I_CC (mA) Terminal VBATT (V) 16.85 16.75 1900.0 1700.0 16.7 1500.0 -50 0 50 100 TEMPERATURE (°C) -50 VCC Leakage Current @ 28V vs. Temperature VIN Leakage Current @ 28V vs. Temperature BATT = 20V 410 400 200 I_VCC_Leakage (μA) I_VIN_Leakage (μA) 250 150 100 50 0 390 380 370 360 350 340 -50 0 50 100 TEMPERATURE (°C) -50 IBATT Leakage @ 20V vs. Temperature 0 50 100 TEMPERATURE (°C) RDS(ON) vs. Temperature 300 0.02 250 0.015 RDS_ON (mΩ) I_BATT_Leakage (μA) 0 50 100 TEMPERATURE (°C) 0.01 0.005 200 150 100 50 0 -50 MP26124 Rev. 1.0 10/10/2017 0 50 100 TEMPERATURE (°C) 0 -50 0 50 100 TEMPERATURE (°C) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 7 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 18V, C1 = 4.7μF, C2 = 22μF, L = 10μH, RS1 = 200mΩ, real/simulation battery load, TA = 25°C, unless otherwise noted. Steady State Steady State Trickle charge, 4 cells, VBATT = 10V CC charge, 4 cells, VBATT = 14.4V CH1: VIN 5V/div. CH1: VIN 5V/div. CH2: VBATT 5V/div. CH2: VBATT 5V/div. CH4: IL 500mA/div. CH4: IL 500mA/div. CH3: VSW CH3: VSW 10V/div. 10V/div. 1µs/div. 1µs/div. Steady State Power On CV charge, 4 cells, VBATT = 16.6V 4 cells, ICHG = 1A, VBATT = 13.2V CH1: VIN 5V/div. CH2: VBATT 5V/div. CH2: VBATT 5V/div. CH1: VIN 5V/div. CH4: IL 500mA/div. CH4: IBATT 500mA/div. CH3: VSW CH3: VSW 10V/div. 10V/div. 1µs/div. 4ms/div. Power Off EN On 4 cells, ICHG = 1A, VBATT = 13.2V 4 cells, ICHG = 1A, VBATT = 13.2V CH1: VIN 5V/div. CH1: VEN 2V/div. CH2: VBATT 5V/div. CH2: VBATT 5V/div. CH4: IBATT 500mA/div. CH4: IBATT 500mA/div. CH3: VSW CH3: VSW 10V/div. 10V/div. 10ms/div. MP26124 Rev. 1.0 10/10/2017 10ms/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 8 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 18V, C1 = 4.7μF, C2 = 22μF, L = 10μH, RS1 = 200mΩ, real/simulation battery load, TA = 25°C, unless otherwise noted. EN Off NTC Control 4 cells, ICHG = 1A, VBATT = 13.2V 4 cells, ICHG = 1A, VBATT = 13.2V CH1: VEN 2V/div. CH2: VBATT 5V/div. CH2: VBATT 5V/div. CH1: VNTC 1V/div. CH4: IBATT 500mA/div. CH4: IBATT 500mA/div. CH3: VSW 10V/div. CH3: VSW 20V/div. 10ms/div. 200ms/div. Timer Out 4 cells, ICHG = 1A, VBATT = 13.2V CH1: VTMR 1V/div. CH2: VBATT 5V/div. CH3: VSW 20V/div. CH4: IBATT 500mA/div. 400µs/div. MP26124 Rev. 1.0 10/10/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 9 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER PIN FUNCTIONS Pin # Name 1 VCC 2 NTC 3 ACOK 4 CHGOK 5 VREF33 6 EN 7 SGND 8 9 10 COMPV COMPI BATT 11 CSP 12 GND 13 TMR 14 BST 15 SW 16 VIN Description IC supply voltage. Thermistor input. Connect a resistor from NTC to VREF33. Connect the thermistor from NTC to ground. Valid input supply indicator. ACOK is an open-drain output. Add a pull-up resistor to ACOK . Logic low indicates the presence of a valid input supply. Charging status indicator. CHGOK is an open-drain output. Add a pull-up resistor to MP26124 Rev. 1.0 10/10/2017 CHGOK . Logic low indicates normal charging. Logic high indicates either a completed charge process or suspended process due to a fault. Internal linear regulator, 3.3V reference output. Bypass VREF33 to GND with a 1μF ceramic capacitor. On/off control input. Definition. Connect SGND to the GND plane. V-LOOP compensation. Decouple COMPV with a capacitor and a resistor. I-LOOP compensation. Decouple COMPI with a capacitor and a resistor. Positive battery terminal. Battery charge current sense positive input. Connect a resistor (RS1) between CSP 200mV and BATT. The full charge current is: ICHG A   . RS1mΩ Ground. GND is the voltage reference for the regulated output voltage. This node should be placed outside of the switching diode (D2) to the input ground path to prevent switching current spikes from inducing voltage noise into the part. Safe timer period. A 0.1µA current charges and discharges the external capacitor decoupled to GND. The capacitor value programs the timer period. Bootstrap. A charged capacitor is required to drive the power switch’s gate above the supply voltage. Connect a capacitor between SW and BST to form a floating supply across the power switch driver. Switch output. Input voltage. The MP26124 regulates an up to 24V input to a voltage suitable for charging a 4-series Li-ion battery pack. Capacitors are required to prevent large voltage spikes from appearing at the input. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 10 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER BLOCK DIAGRAM VIN Current Sense A1 PRE_REGS EN 600kHz OSC BST Regulator Current Limit Comparator 5 bit trim M1 S VREF Q Drive R CTRL R 3 bit trim SW PWM Comparator IREF Mini Refresh L VCC LDO Charge Current Sense VBATT VREF33 CSP x6 FB NTC BATT 0.12V or 1.2V COMP 1.2V FB Max Reflesh Time Max Charge Time FB Charge Control Logic 4V Recharge Comparator 0.12V Charge Current Sense SGND COMPI 2.8V Max Trickle Time Timer 4 cells battery TC/CC Charge Comparator CTRL TMR RS1 A2 GMI GMV COMPV VIN BF Comparator ACOK BATT+300mV GND ACOK CHGOK Figure 1: Functional Block Diagram MP26124 Rev. 1.0 10/10/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 11 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER OPERATION The MP26124 is a peak-current modecontrolled switching charger for use with Li-ion batteries. At the beginning of a cycle, the MOSFET (M1) is off, and the COMP voltage is higher than the output of the current sense amplifier (A1). The pulse-width modulation (PWM) comparator’s output is low, and the rising edge of the 600kHz CLK signal sets the RS flip-flop, which turns on M1, connecting SW and the inductor to the input supply. As the inductor current increases, the output of A1 increases. When this signal exceeds the COMP voltage, the RS flip-flop resets and turns M1 off. The external switching diode (D2) then conducts the inductor current. The MP26124 uses COMP to select the smaller value of GMI and GMV to implement either current loop control or voltage loop control. Current loop control occurs when the battery voltage is low, which results in the saturation of the GMV output. GMI compares the charge current (as a voltage sensed through RS1) against the reference voltage to regulate the charge current to a constant value. When the battery voltage charges up to the reference voltage, the output of GMV goes low and initiates voltage loop control to control the duty cycle to regulate the output voltage. If the charge stays in trickle-charging mode until the time-out condition is triggered, charging terminates until the input power or EN signal refreshes. Otherwise, GMI regulates the charge current to the level set by RS1. The charger operates at constant-current (CC) charging mode. The duty cycle of the switcher is determined by the COMPI voltage, which is regulated by the amplifier GMI. When the battery voltage reaches the constantvoltage mode threshold, GMV regulates COMP and the duty cycle for constant voltage (CV) mode. When the charge current drops to the battery-full threshold (IBF, typical 10% CC), the battery is defined as fully charged. The charger stops charging, and CHGOK goes high to indicate the charge-full condition. If the total charge time exceeds the timer period, the charging terminates immediately and resumes when either the input power or EN signal can restart the charger. Figure 2 shows the typical charge profile of the MP26124. CV charge Threshold Constant Charge Current ICHG VBATT CC charge Threshold Trickle charge The MP26124 has an internal linear regulator (VREF33) to power the internal circuitry. VREF33 can also power external circuitry as long as the load does not exceed the maximum current (30mA). Connect a 1μF bypass capacitor from VREF33 to GND to ensure stability. Charge Cycle (Mode Change: Trickle  CC  CV) At the start of a charging cycle, the MP26124 monitors VBATT. If VBATT is lower than the tricklecharge threshold (VTC, typically 3.0V/cell), the charging cycle starts in trickle-charge mode (10% of the RS1 programmed constant-charge current, ICC) until the battery voltage reaches VTC. MP26124 Rev. 1.0 10/10/2017 IBF CC charge CV charge Trickle Charge Current Charge Full Figure 2: Li-Ion Battery Charge Profile Automatic Recharge After the battery has completely recharged, the charger disables all blocks except for the battery voltage monitor to limit the leakage current. If the battery voltage falls below 4.0V/cell, the MP26124 begins recharging with a soft start. The timer then resets to avoid timer-related charging disruptions. Charger Status Indication The MP26124 has two open-drain status outputs: ACOK and CHGOK . ACOK goes low when the IC supply voltage (VCC) exceeds the under-voltage lockout (UVLO) threshold and the regulated voltage (VIN) is 300mV higher than VBATT to ensure that the regulator can operate www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 12 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER normally. CHGOK indicates the charge status. Table 1 describes the ACOK and CHGOK outputs under different charge conditions. Table 1: Charging Status Indication ACOK CHGOK Charger Status low low low high In charging End of charge, NTC fault, timer out, thermal high high shutdown, EN disable VIN - VBATT < 0.3V VCC < UVLO Timer Operation The MP26124 uses the internal timer to limit the charge period during trickle charge and total charge cycle. Once the charge time exceeds the time limit, the MP26124 terminates charging. A good battery should recharge completely within the allotted time period. Otherwise, the battery has a fault. An external capacitor at TMR programs the time period. When time-out occurs, charging is suspended. The charge cycle can be restarted by refreshing the input power or EN signal or auto-recharge (VBATT falls through 4V/cell). Negative Thermal Coefficient (NTC) Thermistor The MP26124 has a built-in NTC resistance window comparator that allows the MP26124 to sense the battery temperature through the thermistor included in the battery pack. Connect a resistor with an appropriate value from VREF33 to NTC, and connect the thermistor from NTC to GND. A resistor divider determines the voltage on NTC as a function of the battery temperature. Charging stops when the NTC voltage exits the NTC window range. Charging resumes when the voltage is within the NTC window range. The trickle mode charge time can be calculated with Equation (1): TTRICKLE _ TMR  30mins  CTMR 0.1F (1) The total charge time can be calculated with Equation (2): TTOTAL _ TMR  3hours  MP26124 Rev. 1.0 10/10/2017 CTMR 0.1F (2) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 13 MP26124 –24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER OPERATION FLOW CHART POR VUVLOVBATT+0.3V? SYS powered by BATT No Yes ACOK is low No Charging EN? Yes VBATT_TC = 12V VBATT_FULL=16.8V VBATT_RECHG=16V Normal Operation Charger “On”, CHGOK is low Charge Mode? VBATT>=VBATT_FULL VBATT_TC