19-5296; Rev 0; 6/10 Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring The MAX8934G dual-input Li+/Li-Poly linear battery charger with Smart Power SelectorK safely charges a single Li+/Li-Poly cell in accordance with JEITA* recommendations. The MAX8934G monitors the battery temperature (TBATT) while charging, and automatically adjusts the fast-charge current and charge termination voltage as the battery temperature varies. The MAX8934G also monitors the battery temperature while the battery is discharging, and provides a warning flag (OT) to the system in the event that the battery is over temperature. Safety region 2 is supported (see Figure 6 for details). An ultra-low IQ, always-on LDO provides an additional 3.3V supply for system power. The MAX8934G operates with either separate inputs for USB and AC adapter power, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included on-chip. No external MOSFETs are required. The MAX8934G features a Smart Power Selector to make the best use of limited USB or adapter power. Input current limit and battery charge current limit are independently set. Input power not used by the system charges the battery. Charge current limit and DC current limit can be set up to 1.5A and 2A, respectively, while USB input current can be set to 100mA or 500mA. Automatic input selection switches the system load from battery to external power. Features S Li+ Charger with Smart Power Selector, No External MOSFETs Needed S Monitors Battery Temperature and Adjusts Charge Current and Termination Voltage Automatically per JEITA Recommendations S OT Flags System of a Hot Battery During Discharge S Ultra-Low IQ, Always-On 3.3V LDO S Common or Separate USB and Adapter Inputs S Automatic Adapter/USB/Battery Switchover S Load Peaks in Excess of Adapter Rating are Supported by Battery S Input OVP to 16V (DC) and 9V (USB) S 40mI SYS-to-BATT Switch S Thermal Regulation Prevents Overheating S 4.35V SYS Regulation Voltage Ordering Information PART MAX8934GETI+ *JEITA (Japan Electronics and Information Technology Industries Association) Standard, A Guide to the Safe Use of Secondary Lithium Ion Batteries on Notebook–Type Personal Computers, April 20, 2007. 28 Thin QFN-EP** **EP = Exposed pad. Typical Operating Circuit LDO 3.3V ALWAYS-ON LINEAR REGULATOR AC ADAPTER DC SYS Q1 CHARGE CURRENT Applications PDAs, Palmtop, and Wireless Handhelds Portable Media, MP3 Players, and PNDs Digital Still Cameras and Digital Video Cameras Handheld Game Systems PIN-PACKAGE +Denotes a lead(Pb)-free/RoHS-compliant package. The MAX8934G provides a SYS output voltage of 4.35V. Other features include overvoltage protection (OVP), open-drain charge status and fault outputs, power-OK monitors, charge timers, and a battery thermistor monitor. Additionally, on-chip thermal limiting reduces the battery charge-rate to prevent charger overheating. The MAX8934G is available in a 28-pin, 4mm x 4mm, TQFN package. TEMP RANGE -40NC to +85NC LOAD CURRENT SYSTEM LOAD Q3 USB USB Q2 CHARGE AND SYS LOAD SWITCH BATT BATTERY GND MAX8934G Smart Power Selector is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX8934G General Description MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring ABSOLUTE MAXIMUM RATINGS DC, PEN1 to GND..................................................-0.3V to +16V USB to GND.............................................................-0.3V to +9V VL to GND................................................................-0.3V to +4V LDO to GND.......... -0.3V to the lower of +4V and (VSYS + 0.3V) THMEN, THMSW to GND...................... -0.3V to +(VLDO + 0.3V) THM to GND........................................-0.3V to (VTHMSW + 0.3V) PSET, ISET, CT to GND................................ -0.3V to (VL + 0.3V) BATT, SYS, CEN, CHG, OT, DOK, UOK, FLT, DONE, USUS, PEN2 to GND..............-0.3V to +6V EP (Exposed Pad) to GND....................................-0.3V to +0.3V DC Continuous Current (total in two pins)..................... 2.4ARMS SYS Continuous Current (total in two pins).................... 2.4ARMS USB Continuous Current (total in two pins)................... 2.0ARMS BATT Continuous Current (total in two pins).................. 2.4ARMS LDO Continuous Current.............................................. 50mARMS LDO Short-Circuit Duration.......................................... Continuous Continuous Power Dissipation (TA = +70NC) Single-Layer Board (derate 20.8mW/NC above +70NC).......................1666.7mW Multilayer Board (derate 28.6mW/NC above +70NC).......................2285.7mW Operating Temperature Range........................... -40NC to +85NC Junction Temperature....................................... -40NC to +125NC Storage Temperature........................................ -65NC to +150NC Lead Temperature (soldering, 10s).................................+300NC Soldering Temperature (reflow).......................................+260NC Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 6.6 V DC-to-SYS PREREGULATOR DC Operating Voltage Range 4.1 DC Withstand Voltage VBATT = VSYS = 0V 14 V DC Undervoltage Threshold When V DOK goes low, VDC rising, 500mV hysteresis 3.95 4.0 4.05 V DC Overvoltage Threshold When V DOK goes high, VDC rising, 360mV hysteresis 6.8 V DC Operating Supply Current 6.9 7.0 ISYS = IBATT = 0mA, V CEN = 0V 1 2 ISYS = IBATT = 0mA, V CEN = 5V 0.8 1.5 mA DC Suspend Current VDC = V CEN = VUSUS = 5V, VPEN1 = 0V 195 340 FA DC-to-SYS On-Resistance ISYS = 400mA, V CEN = 5V 0.2 0.35 I DC to BATT Dropout Voltage When SYS regulation and charging stops, VDC falling, 150mV hysteresis 10 50 90 mV DC Current Limit VDC = 5V, VSYS = 4V, TA = +25NC RPSET = 1.5kI 1800 2000 2200 RPSET = 3kI 900 1000 1100 RPSET = 6.3kI 450 475 500 VPEN1 = 0V, VPEN2 = 5V (500mA USB mode) 450 475 500 VPEN1 = VPEN2 = 0V (100mA USB mode) 80 95 100 PSET Resistance Range SYS Regulation Voltage 1.5 VDC = 6V, ISYS = 1mA to 1.75A, V CEN = 5V Connecting DC with USB not present 4.29 6.3 4.35 4.4 mA kI V 1.5 ms Connecting DC with USB present 50 Fs Thermal-Limit Temperature Die temperature at when the charging current and input current limits are reduced 100 NC Thermal-Limit Gain ISYS reduction with die temperature (above +100NC) VL Voltage IVL = 0 to 5mA, USB = unconnected Input Current Soft-Start Time 5 3 3.3 2 _______________________________________________________________________________________ %/C 3.6 V Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring (VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS USB-TO-SYS PREREGULATOR USB Operating Voltage Range 4.1 6.6 V 8 V 4.0 4.05 V 6.9 7.0 V 1 2 ISYS = IBATT = 0mA, V CEN = 5V, VPEN2 = 0V 0.9 1.5 USB Suspend Current DC = unconnected, VUSB = V CEN = VUSUS = 5V 190 340 FA USB to SYS On-Resistance DC unconnected, VUSB = V CEN = 5V, ISYS = 400mA 0.22 0.33 I USB-to-BATT Dropout Voltage When SYS regulation and charging stops, VUSB falling, 150mV hysteresis 10 50 90 mV USB Current Limit (See Table 2) DC unconnected, VUSB = 5V, TA = +25NC VPEN1 = 0V, VPEN2 = 5V 450 475 500 VPEN1 = VPEN2 = 0V 80 95 100 SYS Regulation Voltage DC unconnected, VUSB = 6V, VPEN2 = 5V, ISYS = 1mA to 400mA, VCEN = 5V 4.29 4.35 4.4 Input Limiter Soft-Start Time Input current ramp time 50 Fs Thermal-Limit Temperature Die temperature at when the charging current and input current limits are reduced 100 NC Thermal-Limit Gain ISYS reduction with die temperature (above +100NC) VL Voltage DC unconnected, VUSB = 5V, IVL = 0 to 5mA USB Withstand Voltage VBATT = VSYS = 0V USB Undervoltage Threshold When V UOK goes low, VUSB rising, 500mV hysteresis 3.95 USB Overvoltage Threshold When V UOK goes high, VUSB rising, 360mV hysteresis 6.8 USB Operating Supply Current ISYS = IBATT = 0mA, V CEN = VPEN2 = 0V 5 3 3.3 mA mA V %/NC 3.6 V LDO LINEAR REGULATOR LDO Output Voltage DC unconnected, VUSB = 5V, ILDO = 0mA 3.234 3.3 3.366 VDC = 5V, USB unconnected, ILDO = 0mA 3.234 3.3 3.366 DC and USB unconnected, VBATT = 4V, ILDO = 0mA 3.234 3.3 3.366 V ILDO = 0 to 30mA 0.003 BATT-to-SYS On-Resistance VDC = 0V, VBATT = 4.2V, ISYS = 1A 0.04 0.08 I BATT-to-SYS Reverse Regulation Voltage VPEN1 = VPEN2 = 0V, ISYS = 200mA 50 75 105 mV TA = +25NC, VTHM_T2 < VTHM < VTHM_T3 4.175 4.2 4.225 TA = 0NC to +85NC, VTHM_T2 < VTHM < VTHM_T3 4.158 4.2 4.242 TA = +25NC, VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 4.05 4.075 4.1 TA = 0NC to +85NC, VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 4.034 4.075 4.1 LDO Load Regulation %/mA BATTERY CHARGER BATT Regulation Voltage—Safety IBATT = 0mA Region 2 V _______________________________________________________________________________________ 3 MAX8934G ELECTRICAL CHARACTERISTICS (continued) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring ELECTRICAL CHARACTERISTICS (continued) (VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS BATT Recharge Threshold— Safety Region 2 Change in VBATT from DONE to fastcharge restart BATT Fast-Charge Current Range RISET = 10kI to 2kI BATT Charge Current Accuracy VSYS = 5.5V, VTHM_T1 < VTHM < VTHM_T4 (safety region 2) MIN TYP MAX VTHM_T2 < VTHM < VTHM_T3 -145 -104 -65 VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 -120 -80 -40 0.3 RISET = 2kI 1350 1500 1650 RISET = 4kI 675 750 825 RISET = 10kI 270 300 330 RISET = 2kI, VBATT = 2.5V (prequal) 270 300 330 RISET = 4kI, VBATT = 2.5V (prequal) 130 150 170 RISET = 10kI, VBATT = 2.5V (prequal) ISET Output Voltage RISET = 4kI, IBATT = 500mA (VISET = 1.5V at full charge current) VTHM_T1 < VTHM < VTHM_T4 Charger Soft-Start Time Charge-current ramp time BATT Prequal Threshold VBATT rising, 180mV hysteresis BATT Input Current VBATT = 4.2V, ILDO = 0 1.5 UNITS mV A mA 60 0.9 1 1.1 1.5 2.9 ms 3 3.1 No DC or USB power connected, THMEN = low, VCEN = 5V 5 12 No DC or USB power connected, THMEN = high, V CEN = 5V 12 25 0.003 2 DC or USB power connected, V CEN = 5V V V FA DONE Threshold as a Percentage of Fast-Charge Current IBATT decreasing 20 % Maximum Prequal Time From CEN falling to end of prequal charge, VBATT = 2.5V 180 min Maximum Fast-Charge Time From CEN falling to FLT falling 300 min 15 s Maximum Top-Off Time Timer Accuracy -20 +20 % Timer Extend Threshold Percentage of fast-charge current below where the timer clock operates at half-speed 50 % Timer Suspend Threshold Percentage of fast-charge current below where timer clock pauses 20 % 4 _______________________________________________________________________________________ Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring (VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER THERMISTOR MONITOR (Beta = 3964) (Note 2) THM Cold No-Charge Threshold (T1) CONDITIONS ICHG = 0A, when charging is suspended, 2NC hysteresis THM Cold Threshold (T2) VBATT_REG, reduced, 2NC hysteresis THM Hot Threshold (T3) VBATT_REG reduced, 2.5NC hysteresis THM Hot No-Charge Threshold (T4) ICHG = 0mA, when charging is suspended, 3NC hysteresis THM Hot Discharge Threshold (TOT) OT asserts low, 5NC hysteresis THM Input leakage THM = GND or LDO THMSW Output Leakage THMSW = GND THMSW Output Voltage High Sourcing 1mA TA = +25NC TA = +25NC MAX -2.1 0 +2.4 NC 76.4 77.2 77.9 8.2 10 12 NC 66.2 67 67.6 % of THMSW 42.8 45 47.5 NC % of THMSW 29.8 30 30.6 57 60 63.5 NC 19.5 19.8 20.1 % of THMSW 71 75 80 NC 12.6 12.9 13.1 % of THMSW -1 +0.001 +1 0.01 -0.2 +0.001 VIN = 0 to 5.5V Logic-Low Output Voltage Sinking 1mA VOUT = 5.5V +1 0.01 VLDO 0.05 FA FA V 1.3 Low level Logic-Input Leakage Current UNITS % of THMSW TA = +85NC 0.4 Hysteresis Logic-High Output Leakage Current TYP TA = +85NC LOGIC I/O: PEN1, PEN2, CHG, FLT, DONE, DOK, UOK, USUS, THMEN) High level Logic-Input Thresholds MIN 50 V mV TA = +25NC 0.001 TA = +85NC 0.01 1 25 100 TA = +25NC 0.001 1 TA = +85NC 0.01 FA mV FA Note 1: Limits are 100% production tested at TA = +25NC. Limits over the operating temperature range are guaranteed by design. Note 2: NC includes external NTC thermistor error. % of THMSW excludes thermistor beta error and external pullup error. NTC thermistor assumed to be 100kI Q1% nominal, part number Vishay NTHS0603N01N1003FF, external pullup resistor = 100kI Q1%. _______________________________________________________________________________________ 5 MAX8934G ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) 400 200 ENTERING OVLO 700 600 500 1 2 3 4 5 6 7 VUSB RISING VUSB FALLING 400 300 200 100 0 150 100 50 ENTERING OVLO 0 0 1 2 3 4 5 6 7 8 2 3 4 5 6 7 USB VOLTAGE (V) USB VOLTAGE (V) BATTERY INPUT CURRENT vs. BATTERY VOLTAGE (USB DISCONNECTED) BATTERY INPUT CURRENT vs. TEMPERATURE CHARGE CURRENT vs. BATTERY VOLTAGE (100mA USB) 8 6 4 THMEN = 0 2 90 4.7 80 4.6 4.5 4.4 4.3 1 2 3 50 40 30 4.2 20 4.1 10 0 -40 5 4 -15 10 35 60 85 0 VUSB = 5V PEN1 = X, PEN2 = 1 300 1200 250 200 150 100 VDC = 5V PEN1 = 1, PEN2 = X 1000 CHARGE CURRENT (mA) VBATT RISING VBATT FALLING 350 3 4 CHARGE CURRENT vs. BATTERY VOLTAGE (1A DC) MAX8934G toc07 500 2 BATTERY VOLTAGE (V) CHARGE CURRENT vs. BATTERY VOLTAGE (500mA USB) 400 1 TEMPERATURE (°C) BATTERY VOLTAGE (V) 450 VBATT RISING VBATT FALLING 60 4.0 0 VUSB = 5V PEN1 = X, PEN2 = 0 70 MAX8934G toc08 10 4.8 100 VBATT RISING VBATT FALLING 800 600 400 200 50 0 0 0 1 2 3 BATTERY VOLTAGE (V) 4 8 MAX8934G toc06 VBATT = 4V, THMEN = 0, ILDO = 0 USB AND DC UNCONNECTED 4.9 CHARGE CURRENT (mA) THMEN = 1 5.0 BATTERY INPUT CURRENT (µA) 12 CHARGE CURRENT (mA) 1 0 USB VOLTAGE (V) 14 0 VBATT = 4.2V, USUS = 1 200 0 8 MAX8934G toc04 0 MAX8934G toc02 800 250 USB QUIESCENT CURRENT (FA) VUSB RISING VUSB FALLING 600 VBATT = 4.2V, VUSUS = 0V CEN = 1 ISYS = 0A PEN1 = X, PEN2 = 1 MAX8934G toc05 800 USB OPERATING SUPPLY CURRENT (µA) VBATT = 4.2V, VUSUS = 0V CHARGER IN DONE MODE ISYS = 0A 1000 900 MAX8934G toc01 USB OPERATIN SUPPLY CURRENT (µA) 1200 USB SUSPEND CURRENT vs. USB VOLTAGE USB OPERATING SUPPLY CURRENT vs. USB VOLTAGE (CHARGER DISABLED) MAX8934G toc03 USB OPERATING SUPPLY CURRENT vs. USB VOLTAGE (CHARGER ENABLED) BATTERY INPUT CURRENT (uA) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring 5 0 1 2 3 BATTERY VOLTAGE (V) 6 _______________________________________________________________________________________ 4 5 5 Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring NORMALIZED CHARGE CURRENT vs. AMBIENT TEMPERATURE (LOW IC POWER DISSIPATION) 1.0050 1.0025 1.0000 0.9975 0.9950 0.9925 -15 4.210 4.205 4.200 4.195 4.190 4.185 4.180 10 35 60 85 4.170 -40 -15 10 35 BATTERY VOLTAGE (V) SYS OUTPUT VOLTAGE vs. USB VOLTAGE SYS OUTPUT VOLTAGE vs. DC VOLTAGE 4.8 MAX8934G toc11 4.8 VBATT = 4.0V NO SYS LOAD VBATT = 4.0V NO SYS LOAD 4.6 SYS VOLTAGE (V) 4.6 4.4 85 60 AMBIENT TEMPERATURE (°C) MAX8934G toc12 -40 4.2 4.4 4.2 4.0 0 1 2 3 4 5 6 7 4.0 8 0 2 4 6 8 10 12 USB VOLTAGE (V) DC VOLTAGE (V) SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (USB AND DC DISCONNECTED) SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (DC) 4.3 THE SLOPE OF THIS LINE SHOWS THAT THE BATT-TO-SYS RESISTANCE IS 40mI. 4.2 5.5 5.1 SYS VOLTAGE (V) 4.4 VBATT = 4.0V MAX8934G toc13 4.5 4.1 4.0 3.9 3.8 14 MAX8934G toc14 SYS VOLTAGE (V) 4.215 4.175 0.9900 SYS OUTPUT VOLTAGE (V) MAX8934G toc10 1.0075 4.220 BATTERY REGULATION VOLTAGE (V) VUSB = 5V, VBATT = 4V MAX8943G toc09 NORMALIZED CHARGE CURRENT 1.0100 BATTERY REGULATION VOLTAGE vs. TEMPERATURE 4.7 VDC = 6V 4.3 3.9 VBAT = 4V PEN1 = 1, PEN2 = X CEN = 1 3.7 VDC = 5V 3.5 3.6 0 0.5 1.0 1.5 SYS OUTPUT CURRENT (A) 2.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 SYS CURRENT (A) _______________________________________________________________________________________ 7 MAX8934G Typical Operating Characteristics (continued) (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) Typical Operating Characteristics (continued) (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) VL OUTPUT VOLTAGE vs. DC VOLTAGE SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (USB) 3.0 4.9 0.1A, PEN1 = 0, PEN2 = 0 4.7 4.5 MAX8934G toc16 0.5A, PEN1 = 0, PEN2 = 0 4.3 4.1 3.9 2.5 2.0 IVL = 5mA 1.5 1.0 IVL = 0mA 0.5 3.7 3.5 0 0 0.5 1.0 1.5 2.0 3.0 2.5 0 2 4 SYS OUTPUT CURRENT (A) MAX8934G toc17 14 12 3.5 IBAT BATTERY CURRENT (mA) 350 MAX8934G toc18 1.0 4.0 BATTERY VOLTAGE (V) 400 VBAT 10 1.2 4.5 450 300 8 CHARGE PROFILE—820mAh BATTERY ADAPTER INPUT—1A CHARGE CHARGE PROFILE—820mAh BATTERY USB INPUT—500mA CHARGE 500 6 DC VOLTAGE (V) 4.5 4.0 VBAT 3.5 0.8 IBAT 0.6 3.0 0.4 2.5 2.5 0.2 2.0 2.0 120 0 250 3.0 200 150 100 BATTERY VOLTAGE (V) SYS OUTPUT VOLTAGE (V) 5.1 VL OUTPUT VOLTAGE (V) VBATT = 4.0V, VUSB = 5.0V CEN = 1 5.3 3.5 MAX8934G toc15 5.5 BATTERY CURRENT (mA) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring 50 0 0 20 40 60 80 100 1.5 0 20 DC CONNECT WITH NO USB (RSYS = 22I) DC CONNECT WITH USB CONNECTED (RSYS = 22I) MAX8934G toc19 VSYS 4.35V CDC CHARGING IDC 5V/div CSYS CHARGING VBATT VSYS IDC IUSB 5V/div 5V/div 4.35V CSYS CHARGING 1.2A 1A/div 0A 500mA/div 475mA 160mA 0A IBATT MAX8934G toc20 3.6V 3.6V CDC CHARGING 1A/div 1.2A 0A 80 60 TIME (min) TIME (min) 3.8V 40 1A/div -303mA BATTERY CHARGER SOFT-START 400µs/div -1A 0mA IBATT -1A BATTERY CHARGER SOFT-START 400µs/div 8 _______________________________________________________________________________________ 1A/div Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring DC DISCONNECT WITH NO USB (RSYS = 22I) MAX8934G toc21 VBATT MAX8934G toc22 5V/div 3.6V VSYS 4V 3.6V 1.2A VUSB 5V/div 475mA CSYS CHARGING IUSB 160mA VSYS 3.3V VUOK 3.3V VCHG 3.3V 1A/div -1A IBATT -IBATT = CHARGING 4.3V IUSB 0V 475mA VCHG IBATT MAX8934G toc24 -307mA 5V/div VUSUS IUSB 500mA/div 5V/div 3.3V 5V/div 3.3V 5V/div 160mA 500mA/div 3.7V 3.6V VCHG 3.3V IBATT 160mA 500mA/div 5V/div 5V/div 500mA/div VUSB = 5V USB RESUME (RSYS = 22I) LDO OUTPUT VOLTAGE vs. LDO OUTPUT CURRENT (USB DISCONNECTED) 3V 475mA 0A 4.3V 500mA/div 3.7V 5V/div 3.3V 160mA 3.35 5V/div 0V VSYS IBATT 0A 200µs/div 3.6V VCHG 475mA 5V/div 200µs/div BATTERY CHARGER SOFT-START -307mA VUSB = 5V 200µs/div 5V/div 500mA/div VBATT = 4.0V 3.30 LDO OUTPUT VOLTAGE (V) IUSB 3.3V -307mA MAX8934G toc25 VUSUS 0V VSYS 3.6V VUOK 500mA/div USB SUSPEND (RSYS = 22I) MAX8934G toc23 3.7V 5V/div 200µs/div 0mA VSYS 5V/div BATTERY CHARGER -1A SOFT-START -307mA -150mA USB DISCONNECT WITH NO DC (RSYS = 22I) 4.2V 3.7V 5V/div 200µs/div VUSB 500mA/div CDC CHARGING 1A/div 0A IBATT 5V/div 5V MAX8934G toc26 IDC USB CONNECT WITH NO DC (RSYS = 22I) 3.25 DC UNCONNECTED 3.20 VDC = 5.0V 3.15 3.10 3.05 3.00 2.95 0 25 50 75 100 125 150 LDO OUTPUT CURRENT (mA) 175 _______________________________________________________________________________________ 9 MAX8934G Typical Operating Characteristics (continued) (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) Typical Operating Characteristics (continued) (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) LDO OUTPUT VOLTAGE vs. BATTERY VOLTAGE LDO STARTUP WAVEFORMS MAX8934G toc27 VBATT VLDO 3.0 2V/div 3.3V 2V/div 50mA/div IBATT MAX8934G toc28 3.5 3.6V LDO OUTPUT VOLTAGE (V) ILDO = 0 2.5 VBATT FALLING 2.0 VBATT RISING 1.5 1.0 0.5 0 400Fs/div 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) ALWAYS-ON LDO POWER-SUPPLY REJECTION RATIO vs. FREQUENCY VBATT = 3.8V, ILDO = 10mA RESISTIVE LOAD 800 -15 -20 -25 -30 -35 700 600 500 400 300 -40 200 -45 100 -50 MAX8934G toc30 900 OUTPUT NOISE (nV/Hz) VSYS = 3.6V ILDO = 10mA RESISTIVE LOAD -10 LDO NOISE DENSITY vs. FREQUENCY MAX8934G toc29 0 -5 PSRR (dB) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring 0 0.1 1 10 100 0.01 FREQUENCY (kHz) 0.1 1 10 100 FREQUENCY (kHz) THM NORMAL TO THM COLD (< T2) TRANSITION MAX8934G toc31 1V/div VTHM 2.2V 4.2V 4.075V VBAT 200mV/div 420mA IBAT 10I RESISTOR FROM BATT TO GND 200mA/div 10ms/div 10 ������������������������������������������������������������������������������������� 1000 10,000 Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring THM NORMAL TO THM HOT NO CHARGE (> T4) TRANSITION THM NORMAL TO THM HOT (> T3) TRANSITION MAX8934G toc33 MAX8934G toc32 0.65V 500mV/div VTHM 1.0V VBATT 500mV/div VTHM 4.2V 4.2V 4.075V IBATT 200mV/div 500mA/div 940mA 4.075V VBATT THM NORMAL TO T2 TO T1 (COLD, NO CHARGE) TRANSITION MAX8934G toc35 MAX8934G toc34 2.2V 2V/div 3V 100mA/div 20ms/div THM NORMAL TO THM HOT THRESHOLD DISCHARGE TOT VOT 0mA HP6060B ELECTRONIC LOAD SET TO CC MODE 10ms/div VTHM 2V/div 100mA IBATT HP6060B ELECTRONIC LOAD SET TO CC MODE 0V 1V/div VTHM 0.425V 4.2V 2V/div 2.54V 4.075V 1V/div VBATT VBATT 2V/div 3.6V 420mA VSYS 2V/div 3.6V IBATT 0V 200mA/div 10I RESISTOR FROM BATT TO GND 0mA 4ms/div 10ms/div ______________________________________________________________________________________ 11 MAX8934G Typical Operating Characteristics (continued) (TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring Pin Description PIN NAME 1 DONE FUNCTION Charge Complete Output. The DONE active-low, open-drain output pulls low when the charger enters the DONE state. The charger current = 0mA when DONE is low. See Figure 7. DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB inputs. The DC current limit is set with PEN1, PEN2, and RPSET. See Table 2. Both DC pins must be connected together externally. Connect a 10FF ceramic capacitor from DC to GND. The DC inputs should be grounded if not used. 2, 3 DC 4 CEN Active-Low Charger Enable Input. Connect CEN to GND or drive low with a logic signal to enable battery charging when a valid source is connected at DC or USB. Drive high with a logic signal to disable battery charging. 5 PEN1 Input Limit Control 1. See Table 2 for complete information. 6 PEN2 Input Limit Control 2. See Table 2 for complete information. 7 PSET DC Input Current-Limit Setting. Connect a resistor from PSET to GND to program the DC current limit up to 2A (3000V/RPSET). 8 VL 9, 13 GND 10 CT 11 ISET 12 USUS USB Suspend Digital Input. As shown in Table 2, driving USUS high suspends the DC or USB inputs if they are configured as a USB power input. THM Thermistor Input. Connect a negative temperature coefficient (NTC) thermistor with good thermal contact with the battery from THM to GND. Use a thermistor with Beta = 3964. Connect a resistor of equal resistance to the thermistor resistance at +25°C from THM to THMSW so that the battery temperature can be monitored, and the fast-charge current and/or the charge termination voltage is automatically adjusted, in accordance with safety region 2 of the JEITA specification. 14 15 16 Internal Logic LDO Output Bypass Pin. Provides 3.3V when DC or USB is present. Connect a 0.1FF ceramic capacitor from VL to GND. VL powers the internal circuitry and provides up to 5mA to an external load. Ground. Both GND pins must be connected together externally. Charge Timer Program Input. A capacitor from CT to GND sets the maximum prequal and fast-charge timers. Connect CT to GND to disable the timer. Charge Current-Limit Setting. A resistor (RISET) from ISET to GND programs the fast-charge charge current up to 1.5A (3000V/RISET). The prequal charge current is 20% of the set fast-charge charge current. THMEN Thermistor Enable Input. THMEN controls THMSW by connecting the external thermistor pullup resistor and the thermistor monitoring circuit to LDO. Drive THMEN high to enable the thermistor circuit in discharge mode and to connect the external thermistor pullup resistor. Drive THMEN low to disconnect the external thermistor pullup resistor and to disable the thermistor monitoring circuit to conserve battery energy when not charging. THMSW Thermistor Pullup Supply Switch. Drive THMEN high to enable the THMSW, shorting the THMSW output to LDO. Drive THMEN low to open the THMSW switch. THMSW is always on when a valid input source is present and the battery is being charged. When no input source is present, THMSW is controlled by THMEN. THMSW is also active when the battery is being discharged, so that the battery temperature can be monitored for an overtemperature condition. 12 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring PIN NAME FUNCTION 17 LDO Always-On Linear Regulator Output. LDO is the output of an internal always-on 3.3V LDO that provides power to external circuitry. The LDO output provides up to 30mA of current for indicator LEDs or other loads. LDO remains active even when only a battery is present, so that the thermistor monitor circuitry can be activated when the battery is being discharged, and other circuitry can remain powered. Connect a 1FF ceramic capacitor from LDO to GND. 18, 19 USB USB Power Input. USB is capable of delivering up to 0.5A to SYS. The USB current limit is set with PEN2 and USUS. See Table 2. Both USB pins must be connected together externally. Connect a 4.7FF ceramic capacitor from USB to GND. 20, 21 BATT Battery Connection. Connect the positive terminal of a single-cell Li+ battery to BATT. The battery charges from SYS when a valid source is present at DC or USB. BATT powers SYS when neither DC nor USB power is present, or when the SYS load exceeds the input current limit. Both BATT pins must be connected together externally. 22 CHG Charger Status Output. The CHG active-low, open-drain output pulls low when the battery is in fast charge or prequal. Otherwise, CHG is high impedance. 23, 24 SYS System Supply Output. SYS is connected to BATT through an internal 40mI system load switch when DC or USB are invalid, or when the SYS load is greater than the input current limit. When a valid voltage is present at DC or USB, SYS is limited to or 4.35V. When the system load (ISYS) exceeds the DC or USB current limit, SYS is regulated to 75mV below VBATT and both the input and the battery service the SYS load. Bypass SYS to GND with a 10FF ceramic capacitor. Both SYS pins must be connected together externally. 25 OT Battery Overtemperature Flag. The OT active-low, open-drain output pulls low when THMEN is high and the battery temperature is R +75NC. 26 DOK DC Power-OK Output. The DOK active-low, open-drain output pulls low when a valid input is detected at DC. 27 UOK USB Power-OK Output. The UOK active-low, open-drain output pulls low when a valid input is detected at USB. 28 FLT Fault Output. The FLT active-low, open-drain output pulls low when the battery timer expires before prequal or fast charge complete. — EP Exposed Pad. Connect the exposed pad to GND. Connecting the exposed pad does not remove the requirement for proper ground connections to the appropriate pins. ______________________________________________________________________________________ 13 MAX8934G Pin Description (continued) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring OT LDO DC POWER MANAGEMENT DC SYS DC SYS PWR OK 3.3V ALWAYS-ON LOW-IQ LDO CHARGER CURRENT AND VOLTAGE CONTROL CURRENTLIMITED VOLTAGE REGULATOR DOK Li+ BATTERY CHARGER AND SYS LOAD SWITCH ISET BATT SET INPUT LIMIT VL BATT VL LDO FOR IC POWER THERMISTOR MONITOR (SEE FIGURE 5) USB POWER MANAGEMENT THM USB THMSW PWR OK UOK THMEN CURRENTLIMITED VOLTAGE REGULATOR THERMAL REGULATION CHG CHARGE TERMINATION AND MONITOR SET INPUT LIMIT USUS DONE FLT CHARGE TIMER PEN1 PEN2 CHG INPUT AND CHARGER CURRENT-LIMIT LOGIC CONTROL CT MAX8934G CEN PSET GND EP Figure 1. Block Diagram 14 ������������������������������������������������������������������������������������� T Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring RPU 4x 1MI 1 CHARGE DONE ADAPTER DONE OT MAX8934G 2 DC CDC 10FF 3 DC 5 OFF 4 CHARGE ON 500mA 6 100mA 7 DOK 8 CVL 0.1FF 9, 13 CCT 0.068FF THMSW ACTIVE DISABLED 10 15 16 14 100kI NTC 100kI 25C FAULT OUTPUT 27 USB PWR OK 26 DC PWR OK SYS 23 CEN CSYS 10FF SYS 24 PEN2 TO SYSTEM LOAD 1MI PSET CHG 11 OVERTEMPERATURE 28 PEN1 RPSET 1.5kI RISET 3kI FLT UOK 25 22 LDO CHARGE INDICATOR BATT 20 ISET BATT 21 1-CELL Li+ CBATT 4.7FF VL USB 18 GND CT USB 19 THMEN LDO THMSW 1 CUSB 4.7FF 17 2 3 4 5 VBUS DD+ ID GND CLDO 1FF THM EP USUS 12 USB SUSPEND Figure 2. Typical Application Circuit Using Separate DC and USB Connector ______________________________________________________________________________________ 15 MAX8934G TO LDO RPU 1MI MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring TO LDO 5-PIN USB CONNECTOR VBUS DD+ ID GND RPU 1MI CHARGE DONE RPU 4x 1MI 1 DONE 2 DC 1 2 3 4 5 CDC 10FF MAX8934G 4 CHARGE ON DC 5 USB 500mA 6 100mA 7 DOK RISET 3kI 8 CVL 0.1FF 9, 13 CCT 0.068FF 10 THMSW ACTIVE 15 DISABLED 16 14 100kI NTC 100kI 25C 25 OVERTEMPERATURE 28 FAULT OUTPUT 27 USB PWR OK 26 DC PWR OK SYS 23 CEN CSYS 10FF SYS 24 PEN1 1MI CHG PEN2 PSET 22 VLDO TO SYSTEM LOAD CHARGE INDICATOR BATT 20 RPSET 1.5kI 11 FLT UOK 3 DC OFF OT BATT 21 CBATT 4.7FF ISET USB 18 VL USB 19 GND CT LDO 17 CLDO 1FF THMEN THMSW USUS 12 USB SUSPEND THM EP Figure 3. Typical Application Circuit Using a 5-Pin USB Connector or Other DC/USB Common Connector 16 ������������������������������������������������������������������������������������� 1-CELL Li+ Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring COMPONENT (Figures 2 and 3) FUNCTION CDC DC filter capacitor 10FF ±10%, 16V X5R ceramic capacitor (0805) Taiyo Yuden EMK212BJ106KG CUSB USB filter capacitor 4.7FF ±10%, 10V X5R ceramic capacitor (0805) Taiyo Yuden LMK212BJ475KD CVL VL filter capacitor 0.1FF ±10%, 10V X5R ceramic capacitor (0402) Taiyo Yuden LMK105BJ104KV CSYS SYS output bypass capacitors 10FF ±10%, 6.3V X5R ceramic capacitor (0805) Taiyo Yuden JMK212BJ106KD CBATT Battery bypass capacitor 4.7FF ±10%, 6.3V X5R ceramic capacitor (0805) Taiyo Yuden JMK212BJ475KD CCT Charger timing capacitor 0.068FF ±10%, 16V X5R ceramic capacitor (0402) Taiyo Yuden EMK105BJ683KV CLDO LDO output capacitor RPU (x5) Logic-output pullup resistors THM Negative TC thermistor PART NUMBER 1FF ±10%, 6.3V X5R ceramic capacitor (0402) Taiyo Yuden JMK105BJ105KV 1MI ±5% resistor Vishay NTC Thermistor P/N NTHS0603N01N1003FF RTHMSW THM pullup resistor RPSET DC input current-limit programming resistor RISET Fast-charge current programming resistor Detailed Description The MAX8934G is a dual-input linear charger with Smart Power Selector that safely charges a single Li+/Li-Poly cell in accordance with JEITA specifications. The MAX8934G integrates power MOSFETs and control circuitry to manage power flow in portable devices. See Figure 1. The charger has two power inputs, DC and USB. These can be separately connected to an AC adapter output and a USB port, or the DC input could be a single power input that connects to either an adapter or USB. Logic inputs, PEN1 and PEN2, select the correct current limits for two-input or single-input operation. Figure 2 is the typical application circuit using separate DC and USB connectors. Figure 3 is the typical application circuit using a 5-pin USB connector or another DC/USB common connector. In addition to charging the battery, the MAX8934G also supplies power to the system through the SYS output. The charging current is also provided from SYS so that the set input current limit controls the total SYS current, where total SYS current is the sum of the system load current and the battery-charging current. SYS is powered from either the DC input pin or the USB input pin. If both the DC and USB sources are connected, DC takes precedence. 100kI 1.5kI ±1% for 2A limit 3kI ±1% for 1A charging In some instances, there may not be enough adapter current or USB current to supply peak system loads. The MAX8934G Smart Power Selector circuitry offers flexible power distribution from an AC adapter or USB source to the battery and system load. The battery is charged with any available power not used by the system load. If a system load peak exceeds the input current limit, supplemental current is taken from the battery. Thermal limiting prevents overheating by reducing power drawn from the input source. The MAX8934G features an overvoltage limiter at SYS. If the DC or USB input voltage exceeds the SYS regulation voltage, VSYS does not follow VDC or VUSB, but remains at its regulation voltage. The MAX8934G has numerous other charging and power-management features that are detailed in the following sections. A 3.3V ultra-low quiescent current, always-on LDO provides up to 30mA for indicator LEDs and for backup power to the system. This LDO powers the thermistor monitor circuitry and provides bias to the external pullup resistor for the thermistor. ______________________________________________________________________________________ 17 MAX8934G Table 1. External Components List for Figures 2 and 3 MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring Smart Power Selector The MAX8934G Smart Power Selector seamlessly distributes power among the external inputs, the battery, and the system load (see the Typical Operating Circuit). The basic functions performed are: U With both an external power supply (USB or adapter) and battery connected: U When the system load requirements are less than the input current limit, the battery is charged with residual power from the input. U When the system load requirements exceed the input current limit, the battery supplies supplemental current to the load. U When the battery is connected and there is no external power input, the system is powered from the battery. U When an external power input is connected and there is no battery, the system is powered from the external power input. System Load Switch An internal 40mI MOSFET connects SYS to BATT (Q3 in the Typical Operating Circuit) when no voltage source is available at DC or USB. When an external source is detected at DC or USB, this switch is opened and SYS is powered from the valid input source through the input limiter. The SYS-BATT switch also holds up SYS when the system load exceeds the input current limit. If that should happen, the SYS-BATT switch turns on so that the battery supplies additional SYS load current. If the system load continuously exceeds the input current limit, the battery does not charge, even though external power is connected. This is not expected to occur in most cases, since high loads usually occur only in short peaks. During these peaks, battery energy is used, but at all other times the battery charges. Input Limiter The input voltage limiter is essentially an LDO regulator. While in dropout, the regulator dissipates a small I2R loss through the 0.2I MOSFET (Q1 in the Typical Operating Circuit) between DC and SYS. With an AC adapter or USB source connected, the input limiter distributes power from the external power source to the system load and battery charger. In addition to the input limiter’s primary function of passing power to the system and charger loads at SYS, it performs several additional functions to optimize use of available power. Input Voltage Limiting If an input voltage is above the overvoltage threshold (6.9V typ), the MAX8934G enters overvoltage lockout (OVLO). OVLO protects the MAX8934G and downstream circuitry from high-voltage stress up to 14V at DC and 8V at USB. In OVLO, VL remains on, the input switch that sees overvoltage (Q1, Q2, Typical Operating Circuit) opens, the appropriate power-monitor output (DOK, UOK) is high impedance, and CHG is high impedance. If both DC and USB see overvoltage, both input switches (Q1 and Q2, Typical Operating Circuit) open and the charger turns off. The BATT-to-SYS switch (Q3, Typical Operating Circuit) closes, allowing the battery to power SYS. An input is also invalid if it is less than BATT, or less than the DC undervoltage threshold of 3.5V (falling). With an invalid input voltage, SYS connects to BATT through a 40mI switch (Q3, Typical Operating Circuit). Input Overcurrent Protection The current at DC and USB is limited to prevent input overload. This current limit can be selected to match the capabilities of the source, whether it is a 100mA or 500mA USB source, or an AC adapter. When the load exceeds the input current limit, SYS drops to 75mV below BATT and the battery supplies supplemental load current. Thermal Limiting The MAX8934G reduces input limiter current by 5%/NC when its die temperature exceeds +100NC. The system load (SYS) has priority over the charger current, so lowering the charge current first reduces the input current. If the junction temperature still reaches +120NC in spite of charge current reduction, no input (DC or USB) current is drawn, the battery supplies the entire system load, and SYS is regulated at 75mV below BATT. Note that this on-chip thermal-limiting circuitry is not related to and operates independently from the thermistor input. Adaptive Battery Charging While the system is powered from DC, the charger draws power from SYS to charge the battery. If the charger load plus system load exceeds the input current limit, an adaptive charger control loop reduces charge current to prevent the SYS voltage from collapsing. Maintaining a higher SYS voltage improves efficiency and reduces power dissipation in the input limiter. The total current through the switch (Q1 or Q2 in the Typical Operating Circuit) is the sum of the load current at SYS and the battery charging current. The MAX8934G limiter clamps at 4.35V, so input voltages greater than 4.35V can increase power dissipation in the limiter. The MAX8934G input 18 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring DC and USB Connections and Current-Limit Options Input Current Limit The input and charger current limits are set as shown in Table 2. It is often preferable to change the input current limit as the input power source is changed. The MAX8934G facilitates this by allowing different input current limits for DC and USB as shown in Table 2. When the input current limit is reached, the first action taken by the MAX8934G is to reduce the battery charge current. This allows the regulator to stay in dropout during heavy loads, thus reducing power dissipation. If, after the charge current is reduced to 0mA, the load at SYS still exceeds the input current limit, SYS voltage begins to fall. When the SYS voltage drops to BATT, the SYSto-BATT switch turns on, using battery power to support the system load during the load peak. The MAX8934G features flexible input connections (at the DC and USB input pins) and current-limit settings (set by PEN1, PEN2, PSET, and ISET) to accommodate nearly any input power configuration. However, it is expected that most systems use one of two external power schemes: separate connections for USB and an AC adapter, or a single connector that accepts either USB or AC adapter output. Input and charger current limit are controlled by PEN1, PEN2, RPSET, and RISET, as shown in Table 2. Separate Adapter and USB Connectors When the AC adapter and USB have separate connectors, the adapter output connects to DC and the USB source connects to USB. PEN1 is permanently connected high (to DC or VL). The DC current limit is set by RPSET, while the USB current limit is set by PEN2 and USUS. Single Common Connector for USB or Adapter When a single common connector is used for both AC adapter and USB sources, the DC input is used for both input sources. The unused USB inputs should be grounded when an AC adapter is connected at DC, PEN1 should be pulled high to select the current limit set by RPSET. When a USB source is connected, PEN1 should be low to select 500mA, 100mA, or USB suspend (further selected by PEN2 and USUS). PEN1 can be pulled up by the AC adapter power to implement hardware adapter/USB selection. USB Suspend Driving USUS high when PEN1 is low turns off the charger and reduces input current to 190FA to accommodate USB suspend mode. The input limiter is disabled and SYS is supported by BATT. Power Monitor Outputs (UOK, DOK) DOK is an open-drain output that pulls low when the DC input has valid power. UOK is an open-drain output that pulls low when the USB input has valid power. A valid input for DC or USB is between 4.1V and 6.6V. If a single power-OK output is preferred, DOK and UOK can be wire-ORed together. The combined output then pulls low if either USB or DC is valid. Table 2. Input Limiter Control Logic POWER SOURCE DOK UOK PEN1 PEN2 USUS DC INPUT CURRENT LIMIT AC adapter at DC input L X H X X 3000V/RPSET USB power at DC input L X L H L 475mA L X L L L 95mA USB suspend USB power at USB input; DC unconnected DC and USB unconnected L X L X H H L X H L H L X L L H L X X H H H X X X USB INPUT CURRENT LIMIT USB input off; DC input has priority 3000V/RISET 475mA 95mA 0 475mA No DC input MAXIMUM CHARGE CURRENT* 95mA 3000V/RISET USB suspend 0 No USB input 0 *Charge current cannot exceed the input current limit. Actual charge current may be less than the maximum charge current if the total SYS load exceeds the input current limit. ______________________________________________________________________________________ 19 MAX8934G limiter power loss is (VDC – VSYS) x IDC, where VSYS may be as high as 4.35V. The input limiter power loss is not less than 0.2I x IDC2. Also note that the MAX8934G turns off when any input exceeds 6.9V (typ). MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring Soft-Start To prevent input transients that can cause instability in the USB or AC adapter power source, the rate of change of input current and charge current is limited. When a valid DC or USB input is connected, the input current limit is ramped from zero to the set current-limit value (as shown in Table 2). If DC is connected with no USB power present, input current ramps in 1.5ms. If DC is connected with USB already present, input current ramps in 50Fs. When USB is connected with no DC present, input current also ramps in 50Fs. If USB is connected with DC already present, the USB input is ignored. If an adapter is plugged into DC while USB is already powered, the input current limit reramps from zero back up to the DC current limit so that the AC adapter does not see a load step. During this transition, if the input current limit is below the SYS load current, the battery supplies the additional current needed to support the load. Additionally, capacitance can be added to SYS to support the load during input power transitions. When the charger is turned on, charge current ramps from zero to the ISET current value in 1.5ms. Charge current also ramps when transitioning to fast-charge from prequal and when changing the USB charge current from 100mA to 500mA with PEN2. There is no dI/dt limiting, however, if ISET is changed suddenly using a switch at RISET. Battery Charger The battery charger state diagram is illustrated in Figure 7. With a valid DC or USB input, the battery charger initiates a charge cycle when the charger is enabled. It first detects the battery voltage. If the battery voltage is less than the BATT prequal threshold (3.0V), the charger enters prequal mode and charges the battery at 20% of the maximum fast-charge current. This reduced charge rate ensures that the maximum fast-charge current setting does not damage a deeply discharged battery. Once the battery voltage rises to 3.0V, the charger transitions to fast-charge mode and applies the maximum charge current. As charging continues, the battery voltage rises until it approaches the battery regulation voltage where charge current starts tapering down. When charge current decreases to 20% of the fast-charge current, the charger enters a brief 15s top-off state, then DONE pulls low and charging stops. If the battery voltage subsequently drops below the recharge threshold, charging restarts and the timers reset. Charge Enable (CEN) When CEN is low, the charger is on. When CEN is high, the charger turns off. CEN does not affect the SYS output. In many systems, there is no need for the system controller (typically a microprocessor) to disable the charger, because the MAX8934G Smart Power Selector circuitry independently manages charging and adapter/ battery power hand-off. In these situations, CEN can be connected to ground. Setting the Charge Current ISET adjusts charge current to match the capacity of the battery. A resistor from ISET to ground sets the maximum fast-charge current: ICHGMAX = 2000 x 1.5V/RISET = 3000V/RISET Determine the ICHGMAX value by considering the characteristics of the battery. It is not necessary to limit the charge current based on the capabilities of the expected AC adapter/USB charging input, the system load, or thermal limitations of the PCB. The MAX8934G automatically adjusts the charging algorithm to accommodate these factors. Monitoring the Charge Current In addition to setting the charge current, ISET can also be used to monitor the actual current charging the battery. See Figure 4. The ISET output voltage is: VISET = ICHG x 1.5V/ICHGMAX = ICHG x RISET/2000 where ICHGMAX is the set fast-charge current and ICHG is the actual battery charge current. A 1.5V output indicates the battery is being charged at the maximum set fast charge current; 0V indicates no charging. This voltage is also used by the charger control circuitry to set and monitor the battery current. Avoid adding more than 10pF capacitance directly to the ISET pin. If filtering of the charge-current monitor is necessary, add a resistor of 100kI or more between ISET and the filter capacitor to preserve charger stability. Note that the actual charge current can be less than the set fast-charge current when the charger enters voltage mode or when the input current limiter or thermal limiter reduces charge current. This prevents the charger from overloading the input source or overheating the system. Charge Termination When the charge current falls to the termination threshold and the charger is in voltage mode, charging is complete. Charging continues for a brief 15s top-off period and then enters the DONE state where charging stops. The DONE current threshold (IDONE) is set to 20% of the 20 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring VISET (V) 1.5 VISET PREQUAL: t PQ = 180min × 0 DISCHARGING 2000 (1.5V/RISET) 0 C CT 0.068FF FAST CHARGE: t FC = 300min × C CT 0.068FF BATTERY CHARGING CURRENT (A) Figure 4. Monitoring the Battery Charge Current with VISET fast-charge current setting. Note that if charge current falls to IDONE as a result of the input or thermal limiter, the charger does not enter the DONE state. For the charger to enter the DONE state, the charge current must be less than IDONE, the charger must be in voltage mode, and the input or thermal limiter must not be reducing the charge current. The charger exits the DONE state, and fast-charge resumes if the battery voltage subsequently drops 104mV or if CEN is cycled. Charge Status Outputs TOP − OFF:t TO = 15s While in fast-charge mode, a large system load or device self-heating can cause the MAX8934G to reduce charge current. Under these circumstances, the fast-charge timer adjusts to ensure that adequate charge time is still allowed. Consequently, the fast-charge timer is slowed by 2x if charge current is reduced below 50% of the programmed fast-charge level. If charge current is reduced to below 20% of the programmed level, the fast-charge timer is paused. The fast-charge timer is not adjusted if the charger is in voltage mode where charge current reduces due to current tapering under normal charging. Charge Output (CHG) CHG is an open-drain, active-low output that is low during charging. CHG is low when the battery charger is in its prequalification and fast-charge states. When charge current falls to the charge termination threshold (IDONE) and the charger is in voltage mode, CHG goes high impedance. CHG goes high impedance if the thermistor causes the charger to enter temperature suspend mode. To exit a fault state, toggle CEN or remove and reconnect the input source(s). Note also that thermistor out of range or on-chip thermal-limit conditions are not considered faults. When the MAX8934G is used in conjunction with a FP, connect a pullup resistor between FLT and the logic I/O voltage to indicate fault status to the FP. Alternatively, FLT can sink up to 20mA for an LED indicator. When the MAX8934G is used with a microprocessor (FP), connect a pullup resistor between CHG and the logic I/O voltage to indicate charge status to the FP. Alternatively, CHG can sink up to 20mA for an LED indicator. The MAX8934G thermistor monitor is configured to execute JEITA recommendations regarding Li+/Li-Poly battery charging by adjusting the fast charge current and/or the charge termination voltage accordingly (see Figure 6 ). Connect the THM input to an external negative temperature coefficient (NTC) thermistor to monitor battery or system temperature. Since the thermistor monitoring circuit employs an external bias resistor from THM to THMSW, the thermistor is not limited only to 10kI (at Charge DONE Output (DONE) DONE is an open-drain, active-low output that goes low when charging is complete. The charger enters its DONE state 15s after the charge current falls to the Thermistor Monitor ______________________________________________________________________________________ 21 MAX8934G charge-termination threshold (IDONE) and the charger is in voltage mode. The charger exits the DONE state, and fast-charge resumes, if the battery voltage subsequently drops 104mV, or if input power or CEN is cycled. When the MAX8934G is used in conjunction with a FP, connect a pullup resistor between DONE and the logic I/O voltage to indicate charge status to the FP. Alternatively, DONE can sink up to 20mA for an LED indicator. Fault Output (FLT) and Charge Timer FLT is an open-drain, active-low output that goes low during a battery fault. The fault state occurs when either the prequal or fast-charge timer expires. The prequal and fast-charge fault timers are set by CCT: MONITORING THE BATTERY CHARGE CURRENT WITH VISET MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring +25NC). Any thermistor resistance can be used as long as the value of RTHMSW is equivalent to the thermistor’s +25NC resistance. The MAX8934G THM thresholds are optimized for a thermistor Beta of 3964. The general relation of thermistor resistance to temperature is defined by the following equation: R T = R 25 the fast-charge current, depending on the sensed battery temperature. If the battery temperature exceeds the THM hot overtemperature threshold and THMEN is high, the OT flag pulls low. Typical systems connect OT to a FP input so that the system can safely shut down. Always-On LDO 1 1 β T 273 C 298 + ° °C ×e The ultra-low quiescent current LDO is always on and is preset to an output voltage of 3.3V. The LDO provides up to 30mA output current. When DC and USB are invalid and the battery is discharging, the LDO output voltage tracks VSYS as it drops below 3.3V. A 1FF ceramic capacitor connected from LDO to GND is recommended for most applications. where: RT = The resistance in ohms of the thermistor at temperature T in NC R25 = The resistance in ohms of the thermistor at +25NC Power Dissipation PCB Layout and Routing A = The material constant of the thermistor Good design minimizes ground bounce and voltage gradients in the ground plane. GND should connect to the power-ground plane at only one point to minimize the effects of power-ground currents. Battery ground should connect directly to the power-ground plane. Connect GND to the exposed pad directly under the IC. Use multiple tightly spaced vias to the ground plane under the exposed pad to help cool the IC. Position input capacitors from DC, SYS, BATT, and USB to the power-ground plane as close as possible to the IC. Keep high current traces such as those to DC, SYS, and BATT as short and wide as possible. Refer to the MAX8934A Evaluation Kit for a suitable PCB layout example. T = The temperature of the thermistor in NC Charging is suspended when the thermistor temperature is out of range (VTHM_T1 < VTHM or VTHM < VTHM_T4). The charge timers are also suspended and hold their state but no fault is indicated. When the thermistor comes back into range, charging resumes and the charge timer continues from where it left off. The THMEN input controls THMSW and the thermistor monitor circuitry when the battery charger is disabled, providing the user with the means to minimize the battery current drain caused by the thermistor monitor. The THMEN input is ignored while the battery is charging, since the thermistor must be monitored at all times. While charging, the thermistor monitor is used to automatically adjust the charge termination voltage and/or Table 3. Package Thermal Characteristics 28-PIN 4mm x 4mm THIN QFN SINGLE-LAYER PCB MULTILAYER PCB 1666.7mW (derate 20.8mW/NC above +70NC) 2285.7mW (derate 28.6mW/NC above +70NC) BJA 48NC/W 35NC/W BJC 3NC/W 3NC/W Continuous Power Dissipation 22 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934G SYS LOW-IQ, ALWAYS-ON 3.3V LDO TRACKS SYS WHEN DC AND USB ARE NOT PRESENT, THE BATTERY IS BEING DISCHARGED, AND VBATT P 3.3V. LDO CHG VINT CHG THMEN CHG THMSW CHARGER CONTROL RTHMSW T4 (60NC) + OT CHG THERMISTOR MONITOR THM VINT VINT VINT T3 (45NC) T + CHG VINT VINT T2 (10NC) + CHG VINT VINT TOT (75NC) + NOT CHARGING THMEN VINT VINT T1 (0NC) + CHG Figure 5. Thermistor Monitor Details ______________________________________________________________________________________ 23 BATT REGULATION VOLTAGE (V) (VBATT_REG) T1 T2 0 10 T1 T2 0 10 T3 T4 4.2 4.1 4.075 4.0 C FAST-CHARGE CURRENT (ICHG) MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring 25 45 60 TEMPERATURE (NC) T3 T4 45 60 85 0.5C 25 85 TEMPERATURE (NC) Figure 6. Safety Region 2: Fast-Charge Currents and Charge Termination Voltages 24 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring UOK AND DOK = HIGH-Z CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z ICHG = 0mA CEN = HIGH OR REMOVE AND RECONNECT THE INPUT SOURCE(S) TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S) UOK OR DOK = LOW CEN = 0 RESET TIMER STATE DIAGRAM IS FOR 10NC < TEMP < +45NC, OUTSIDE OF THIS RANGE SEE FIGURE 6 ANY STATE PREQUAL UOK OR DOK = LOW CHG = LOW FLT = HIGH-Z DONE = HIGH-Z 0V P VBATT P 3V ICHG = ICHGMAX 10 VBATT > 3V, RESET TIMER VBATT < 2.82V, RESET TIMER FAST-CHARGE VBATT < 2.82V RESET TIMER UOK OR DOK = LOW CHG = LOW FLT = HIGH-Z DONE = HIGH-Z 3V P VBATT P 4.2V ICHG = ICHGMAX ICHG < IDONE AND VBATT = 4.2V AND THERMAL OR OUTPUT LIMIT NOT EXCEEDED RESET TIMER ICHG > IDONE RESET TIMER (PQ, FC, TOP-OFF) ANY CHARGING STATE VTHM_T1 < VTHM < VTHM_T4 TIMER RESUME VTHM_T1 < VTHM OR VTHM < VTHM_T4 TIMER SUSPEND TEMPERATURE SUSPEND ICHG = 0mA UOK OR DOK = PREVIOUS STATE CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z VTHM < VTHM_OT VTHM > VTHM_OT OVERTEMP OT = LOW TIMER > tPQ FAULT UOK AND DOK = LOW CHG = HIGH-Z FLT = LOW DONE = HIGH-Z ICHG = 0mA TIMER > tFC (TIMER SLOWED BY 2X IF ICHG < ICHGMAX/2, AND PAUSED IF ICHG < ICHGMAX/5 WHILE BATT < 4.2V) TOP-OFF UOK OR DOK = LOW CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z BATT = 4.2V ICHG = IDONE VBATT < 4.1V RESET TIMER TIMER > 15s DONE UOK OR DOK = LOW CHG = HIGH-Z FLT = HIGH-Z DONE = LOW 4.1V < VBATT < 4.2V ICHG = 0mA Figure 7. Charger State Diagram ______________________________________________________________________________________ 25 MAX8934G NOT READY Pin Configuration USB USB LDO THMSW THMEN TOP VIEW BATT PROCESS: BiCMOS BATT Chip Information 21 20 19 18 17 16 15 CHG 22 14 THM SYS 23 13 GND 12 USUS 11 ISET DOK 26 10 CT UOK 27 9 GND 8 VL SYS 24 MAX8934G OT 25 *EP 3 4 5 6 7 CEN PEN1 PEN2 PSET 2 DC 1 DC FLT 28 DONE MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring THIN QFN *EXPOSED PAD 26 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE CODE OUTLINE No. LAND PATTERN NO. 28 TQFN-EP T2844+1 21-0139 90-0068 24L QFN THIN.EPS PACKAGE TYPE ______________________________________________________________________________________ 27 MAX8934G Package Information MAX8934G Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 28 ������������������������������������������������������������������������������������� Dual-Input Linear Charger, Smart Power Selector with Advanced Battery Temperature Monitoring REVISION NUMBER REVISION DATE 0 6/10 DESCRIPTION DATE Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2010 Maxim Integrated Products 29 Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX8934G Revision History