Freescale Semiconductor Advance Information Document Number: MC34676 Rev. 1.0, 10/2008 Dual 28 V Input Voltage Charger with Linear Regulator 34676 The 34676 is a dual 28 V input voltage and fully-integrated single cell Li-Ion battery charger, targeting smart handheld applications. One of the inputs is optimized for charging with a USB port, and the second is optimized for an AC/DC adapter power source. The charger has two 28 V power devices, to eliminate the need of any external power source selection and input over-voltage protection circuitry. Each of the power devices independently controls the charge current from the input, and performs as an independent charger. Only one of the two chargers operate at a time. The AC charger current and the USB charger current are programmable, up to 1.2 A and 400 mA, with an external resistor respectively. The voltage across the two external resistors is also used to monitor the actual charge current through each charger respectively. The EOC current of both chargers is the same, and programmable by an external resistor. The 4.85 V regulator can be used to power a subsystem directly. The 34676 has a 5% constant current accuracy for the AC Charger over -40 to 85oC, and a 1.0% constant voltage accuracy over -40 to 85oC. A charge current thermal foldback feature, limits the charge current when the IC internal temperature rises to a preset threshold. Features BATTERY CHARGER EP SUFFIX (PB-FREE) 98ASA10814D 12-PIN µDFN ORDERING INFORMATION Device Temperature Range (TA) Package MC34676BEP/R2 -40°C to 85°C 12-UDFN Applications • ±1.0% voltage accuracy over -45 to 85°C • No external MOSFET, reverse blocking diode, or current sense resistor are required • Additional voltage regulated output powered by USB input • Battery detection input • Charge current monitor with thermal limits • Integrated input over-voltage protection • Pb-free packaging designated by suffix code EP • • • • • Cell Phone Smart Phone PDA, PMP, PND, Handheld Portable Devices Portable Medical Devices 34676B BAT BATDET USBOUT AC C1 USB C2 GND IMIN IUSB VDDIO PPR ISET C4 C3 USBEN CHG MCU RIMIN RIUSB RISET USB AC Figure 1. 34676B Simplified Application Diagram * This document contains certain information on a new product. Specifications and information herein are subject to change without notice. © Freescale Semiconductor, Inc., 2008. All rights reserved. INTERNAL BLOCK DIAGRAM INTERNAL BLOCK DIAGRAM USBOUT AC BAT USB VAC Mon VUSB Mon VAC VBAT Analog Control VBAT VUSB VREF Temp Sense VOS VOS TKL VBAT VTKL PPR RCH VBAT VRCH Logic CHG EOC VEOC IBAT/K 1.75 V OSC USBEN IBATDET BATDET IMIN ISET IUSB GND Figure 2. 34676 Simplified Internal Block Diagram 34676 2 Analog Integrated Circuit Device Data Freescale Semiconductor PIN CONNECTIONS PIN CONNECTIONS Transparent Top View AC USB PPR CHG USBEN IMIN EPAD BATDET BAT USBOUT ISET GND IUSB Figure 3. 34676 Pin Connections Table 1. 34676 Pin Definitions A functional description of each pin can be found in the Functional Pin Description section beginning on page 14. Pin Number Pin Name Pin Function Formal Name Definition 1 AC Input AC Input Supply 2 USB Input USB Input Supply 3 PPR Output Power Present Indicator Open-drain output to indicate the input power status. 4 CHG Output Charge Status Indicator Open-drain output to indicate the charge status. 5 USBEN Input Charger Selection 6 IMIN Output End-of-charge Current Setting End-of-charge (EOC) current setting. 7 IUSB Output USB Charger CCmode Current Setting and Charger Current Monitor USB charger CC-mode current setting and charge current monitoring. 8 GND N/A Ground 9 ISET Output AC Charger CC-mode Current Setting and Charge Current Monitor 10 USBOUT Output USB Regulator Output The USB input 4.85 V linear regulator with 45 mA current output capability. 11 BAT Output Charger Output 12 BATDET Input Battery Detection EPAD EPAD N/A Thermal Enhanced PAD Power input from an AC/DC adapter. Power input from a USB port. Logic input. Low logic voltage selects the AC charger; high logic voltage selects the USB charger. Ground. AC charger CC-mode current setting and charge current monitoring. Charger output. Connect this pin to the battery. Battery connection status detection. The exposed pad for thermal dissipation enhancement. Must be soldered on the large ground plane on the PCB to increase the thermal dissipation. 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 3 ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS Table 2. Maximum Ratings All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device. Ratings Symbol Value Unit VAC, VUSB -0.3 to 28 V VPPR, VCHG -0.3 to 12 V VBAT, VBATDET, VUSBEN, VUSBOUT, VISET, VIUSB, VIMIN -0.3 to 5.5 V ELECTRICAL RATINGS Input Supply Voltage Pins Charge State Indication Pins BAT, BATDET, USBEN, USBOUT, ISET, IUSB, IMIN Pins ESD Voltage(1) VESD V Human Body Model (HBM) ±2000 Machine Model (MM) ±200 THERMAL RATINGS Operating Ambient Temperature Range Storage Temperature Range Peak Package Reflow Temperature During Maximum Junction Temperature Reflow(2), (3) TA -40 to +85 °C TSTG -65 to +150 °C TPPRT Note 3 °C TJ +150 °C RθJC 24 °C/W RθJA 90 (4) Thermal Resistance Junction-to-Case Junction-to-Ambient Notes 1. ESD testing is performed in accordance with the Human Body Model (HBM) (CZAP = 100 pF, RZAP = 1500 Ω), and the Machine Model (MM) (CZAP = 200 pF, RZAP = 0 Ω). 2. 3. 4. Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause malfunction or permanent damage to the device. Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow Temperature and Moisture Sensitivity Levels (MSL). Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics. Device mounted on the Freescale EVB test board per JEDEC DESD51-2. 34676 4 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics Characteristics noted under conditions VAC = VUSB = 5.0 V, -40°C ≤ TA ≤ 85°C, C1 = C2 = C4 = 1.0 μF and C3 = 0.1 μF (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Rising 3.0 - 3.9 Falling - 2.8 - Rising 3.0 - 3.9 Falling - 2.8 - Rising - - 60 Falling 3.0 - - Unit POWER-ON RESET (POR) AC POR Threshold USB POR Threshold VPORAC V VPORUSB V INPUT-BAT OFFSET VOLTAGE (VOS) AC Input-BAT Offset Voltage Threshold USB Input-BAT Offset Voltage Threshold VOSAC mV VOSUSB mV Rising - - 60 Falling 3.0 - - Rising 6.6 6.8 7.0 Falling 6.3 - - - 200 - Rising 5.65 5.85 6.1 Falling 5.55 - - - 60 - mV - - 1.0 μA INPUT OVER-VOLTAGE PROTECTION (OVP) AC Input Over-voltage Threshold VOVPAC V AC Input Over-voltage Rising Threshold Hysteresis USB Input Over Voltage Threshold VOVPUSB mV V USB Input Over-voltage Rising Threshold Hysteresis STANDBY CURRENT BAT Pin Sink Current ISTDBY Input not powered AC Pin Input Supply Current IACS Charger disabled - - 750 μA Charger enabled(5) - 1.2 - mA USB Pin Input Supply Current IUSBS Charger disabled - - 750 μA Charger enabled(5) - 1.2 - mA Notes 5. Supply current does not include the current delivered to the battery through the BAT pin. 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 5 ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics (continued) Characteristics noted under conditions VAC = VUSB = 5.0 V, -40°C ≤ TA ≤ 85°C, C1 = C2 = C4 = 1.0 μF and C3 = 0.1 μF (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max IBAT = 10 mA, TA = 25°C 4.184 4.20 4.216 IBAT = 10 mA, TA = -40 to 85°C 4.158 4.20 4.242 Unit VOLTAGE REGULATION Regulated Output Voltage VBAT V AC Charger Power MOSFET ON Resistance (VBAT = 4.0 V, IBAT = 500 mA, RISET = 3.75 kΩ) RDS(ON)AC - - 500 mΩ USB Charger Power MOSFET ON Resistance (VBAT = 4.0 V, IBAT = 300 mA, IUSB is floating) RDS(ON)USB - - 1000 mΩ IAC 0.1 - 1.2 A CHARGE CURRENT AC Charger CC-mode Current Range AC Charger CC-mode Current Accuracy IAC When set current between 300 mA to 1.2 A 95% 100% 105% When set current between 100 to 300 mA(6) 90% 100% 110% USB Charger CC-mode Current Range IUSB When IUSB is floating When IUSB is pulled down to ground with a resistor USB Charger CC-mode Current Accuracy mA - 400 - 100 - 400 85% 100% 115% IUSB AC Trickle Charge Current (% of programmed CC current) ITRKLAC 16% 20% 24% IAC USB Trickle Charge Current (% of programmed CC current) ITRKLUSB 16% 20% 24% IUSB When RIMIN = 200 kΩ 5.5 10 12.3 When RIMIN = 25 kΩ 60 80 98 SR 20 - 120 mA/μs ISET Voltage for IAC Reference VISET - 1.0 - V IUSB Voltage for IUSB Reference VIUSB - 1.0 - V IMIN Voltage for IEOC Reference VIMIN - 0.5 - V VRECH 4.05 4.10 4.15 V VRECHHYS - 25 - mV VTRK 2.5 2.7 2.8 V VTRKHYS - 100 - mV TLM 95 110 125 °C End-of-Charge Threshold Current Slew Rate (On both rising and transitions) IEOC mA CHARGE THRESHOLD Recharge Voltage Threshold Recharge Voltage Threshold Hysteresis Trickle Charge Threshold Trickle Charge Threshold Hysteresis CHARGE CURRENT THERMAL FOLDBACK Current Foldback Die Temperature Limit Notes 6. Not tested but guaranteed by design. 34676 6 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics (continued) Characteristics noted under conditions VAC = VUSB = 5.0 V, -40°C ≤ TA ≤ 85°C, C1 = C2 = C4 = 1.0 μF and C3 = 0.1 μF (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit 4.63 4.85 5.0 - - 250 46 - - mA - 200 - kΩ USBOUT REGULATOR Output Voltage VUSBOUT VUSB=5.35 V, IUSBOUT=10 mA V Dropout Voltage mV At 45 mA output current Output Current Limit Output Pull-down Resistance BATTERY DETECTION INPUT Internal Pull-up Current IBATDET 2.0 4.0 6.0 μA Comparator Falling Threshold VBATDET 1.65 1.75 1.85 V - 200 - mV Hysteresis LOGIC INPUT AND OUTPUT USBEN Input High VIH 1.5 - - V USBEN Input Low VIL - - 0.5 V - - 5.0 μA USBEN Internal Pull-down Current Open-drain Output Low 10 mA sink current PPR and CHG Leakage Current When the Output is High-impedance V - - 0.6 - - 1.0 μA VCHG = VPPR = 5.0 V 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 7 ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS Table 4. Dynamic Electrical Characteristics Characteristics noted under conditions VAC = VUSB = 5.0 V, -40°C ≤ TA ≤ 85°C, C1 = C2 = C4 = 1.0 μF and C3 = 0.1 μF (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit tEOC 500 - 1000 ms fOSC 42 50.0 54.5 kHz END-OF-CHARGE EOC Filtering Time OSCILLTOR Oscillation Frequency ELECTRICAL PERFORMANCE CURVES 4 450 3 300 2 150 Charger Current 25 50 75 1 1.0 0.8 VISET (V) Battery Voltage Battery Voltage (V) Charger Current (mA) 600 0 0 1.2 5 750 0.6 0.4 0.2 0.0 4.0 0 100 125 150 175 4.5 5.0 Charge Time ( min) 6.5 7.0 VBAT=3.7 V, RISET=5.22 kΩ, TA=25oC 3000 1.0 2500 RISET=26.7kΩ RISET=5.22kΩ 0.8 2000 VISET (V) AC Pin Supply Current ( μA) 6.0 Figure 6. VISET vs VAC Figure 4. AC Charger Complete Charge Cycle VAC=5.0 V, RISET=5.22 kΩ, 740mAh Battery, TA=25oC Charger Enabled 1500 1000 500 0 5.5 Input Voltage (V) 4 5 6 Input Voltage (V) Figure 5. AC Pin Supply Current vs VAC IBAT=0 mA, TA=25oC 0.4 0.2 Charger Disabled 3 0.6 7 0.0 0 150 300 450 600 750 Charger Current (mA) Figure 7. VISET vs AC Charger Charge Current VAC=5.0 V, TA=25oC 34676 8 Analog Integrated Circuit Device Data Freescale Semiconductor 750 4.24 RISET=5.22kΩ 4.22 600 4.20 VBAT (V) Constant Charge Current (mA) ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES 450 300 150 0 4.0 4.18 4.16 4.14 4.12 RISET=26.7kΩ 4.5 5.0 5.5 6.0 6.5 4.10 -40 7.0 -20 AC pin supply current ( μA) Charge Current (mA) 600 450 300 RISET=5.22kΩ RISET=26.7kΩ 2 3 4 5 1750 Charger Enabled 1500 1250 1000 750 500 Charger Disabled 250 0 -40 -20 0 20 40 60 80 o Temperature ( C) Figure 9. AC Charger Charge Current vs Battery Voltage VAC=5.0 V, TA=25°C Figure 12. AC Pin Supply Current vs TA VAC=5.0 V, IBAT=0 mA 1.10 200 1.05 RISET=5.22kΩ VISET ( V) Trickle Charge Current (mA) 80 2000 Battery Voltage (V) 150 60 Figure 11. VBAT vs TA VAC=5.0 V, IBAT=0 mA 750 1 40 Temperature ( C) Figure 8. AC Charger CC Current vs VAC VBAT=3.7 V, TA=25°C 0 0 20 o Input Voltage (V) 150 0 100 1.00 0.95 50 RISET=26.7kΩ 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Input Voltage (V) Figure 10. AC Charger Trickle Charge Current vs VAC VBAT=2.0 V, TA=25°C 0.90 -40 -20 0 20 40 60 80 o Temperature ( C) Figure 13. VISET vs TA VAC=5.0 V, RISET=5.22 kΩ, VBAT=3.7 V 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 9 ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES Charger Current (mA) 500 RDS(ON) ( mΩ) 400 350 300 250 -40 -20 0 20 40 60 5 400 Battery Voltage 300 3 200 2 Charger Current 100 0 0 80 1 50 o 900 RISET=5.22kΩ 600 450 300 0 -40 RISET=26.7kΩ -20 0 20 40 60 80 2500 2000 1500 1000 Charger Enabled 500 0 Charger Disabled 3 4 IBAT=0 mA, TA=25oC 250 1.2 200 1.0 RISET=5.22kΩ 100 RISET=26.7kΩ -20 0 20 40 6 Figure 18. USB Pin Supply Current vs VUSB VIUSB (V) Trickle Charge Current ( mA) Figure 15. AC Charger CC Current vs TA VAC=5.0 V, VBAT=3.7 V 0 -40 5 Input Voltage (V) Temperature ( C) 50 0 200 3000 o 150 150 Figure 17. USB Charger Complete Charge Cycle VUSB=5.0 V, RIUSB=6.52 kΩ, 740 mA Battery, TA=25oC USB Pin Supply Current ( μA) Constant Charge Current ( mA) Figure 14. AC Charger RDS(ON) vs TA VBAT=4.0 V, IAC=750 mA, IBAT=500 mA 150 100 Charge Time ( min) Temperature ( C) 750 4 Battery Voltage (V) 450 60 80 o Temperature ( C) Figure 16. AC Charger Trickle Charge Current vs TA VAC=5.0 V, VBAT=2.0 V 0.8 0.6 0.4 0.2 0.0 4.0 4.5 5.0 5.5 6.0 Input Voltage (V) Figure 19. VIUSB vs VUSB VBAT=3.7 V, RIUSB=9.76 kΩ, TA=25oC 34676 10 Analog Integrated Circuit Device Data Freescale Semiconductor 1.0 RIUSB=9.76kΩ VIUSB (V) 0.8 0.6 0.4 0.2 0.0 0 50 100 150 200 250 300 Trickle Charge Current (mA) ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES 200 150 IUSB pin is floating 100 RIUSB=9.76kΩ 50 0 4.0 4.5 Charger Current (mA) 6.0 Figure 23. USB Charger Trickle Charge Current vs VUSB VBAT=2.0 V, TA=25°C 5.00 400 4.95 IUSB pin is floating 300 200 VUSBOUT (V) Constant Charge Current (mA) =25oC RIUSB=9.76kΩ 100 0 4.0 4.90 4.85 4.80 4.75 4.5 5.0 5.5 4.70 0 6.0 10 30 40 50 Figure 24. VUSBOUT vs IUSBOUT VUSB=5.0 V, TA=25°C Figure 21. USB Charger CC Current vs VUSB VBAT=3.7 V, TA=25°C 6.0 500 5.5 VUSBOUT (V) IUSB pin is floating 400 300 200 RIUSB=9.76kΩ 100 0 0 20 IUSBOUT (mA) Input Voltage (V) Charge Current (mA) 5.5 Input Voltage (V) Figure 20. VIUSB vs USB Charger Charge Current VUSB=5.0 V, TA 5.0 5.0 4.5 4.0 3.5 1 2 3 4 5 Battery Voltage (V) Figure 22. USB Charger Charge Current vs VBAT VUSB=5.0 V, TA=25°C 3.0 3.0 3.5 4.0 4.5 5.0 VUSB (V) 5.5 6.0 Figure 25. VUSBOUT vs VUSB IUSBOUT=0 mA, TA=25oC 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 11 ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES 900 4.24 850 4.22 800 RDS(ON) ( mΩ) VBAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 -40 750 700 650 600 550 -20 0 20 40 60 500 -40 80 -20 o 1500 1250 1000 Charger Disabled 500 250 0 20 40 60 80 Constant Charge Current ( mA) USB Pin Supply Current ( μA) Charger Enabled -20 IUSB pin is floating 400 300 200 RIUSB=9.76kΩ 100 0 -40 -20 0.9 0.8 0.7 0.6 60 o Temperature ( C) Figure 28. VIUSB vs TA VUSB=5.0 V, RIUSB=9.76 kΩ, VBAT=3.7 V 80 Trickle Charge Current ( mA) VIUSB ( V) 1.0 40 40 60 80 Figure 30. USB Charger CC Current vs TA VUSB=5.0 V, VBAT=3.7 V 1.1 20 20 Temperature ( C) Figure 27. USB Pin Supply Current vs TA VUSB=5.0 V, IBAT=0 mA 0 0 o Temperature ( C) -20 80 500 o 0.5 -40 60 Figure 29. USB Charger RDS(ON) vs TA VBAT=4.0 V, IUSB=400 mA, IBAT=300 mA 2000 0 -40 40 Temperature ( C) Figure 26. VBAT vs TA VUSB=5.0 V, IBAT=0 mA 750 20 o Temperature ( C) 1750 0 250 200 150 IUSB pin is floating 100 RIUSB=9.76kΩ 50 0 -40 -20 0 20 40 60 80 o Temperature ( C) Figure 31. USB Charger Trickle Current vs TA VUSB=5.0 V, VBAT=2.0 V 34676 12 Analog Integrated Circuit Device Data Freescale Semiconductor 4.84 IUSBOUT=0mA VUSBOUT ( V) 4.82 IUSBOUT=50mA 4.80 4.78 4.76 -40 -20 0 20 40 60 80 Recharge Voltage Threshold ( V) ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES 4.20 4.15 4.10 4.05 4.00 3.95 -40 -20 o 0.6 0.4 0.2 40 60 80 o Temperature ( C) Figure 33. BAT Pin Current vs TA VBAT=4.2 V, Input Not Powered or Charger Disabled End-of-charge Current ( mA) BAT Pin Current ( μA) 0.8 20 60 80 Figure 34. Recharge Voltage Threshold vs TA VAC=5.0 V or VUSB=5.0 V 1.0 0 40 Temperature ( C) Figure 32. VUSBOUT vs TA VUSB=5.0 V -20 20 o Temperature ( C) 0.0 -40 0 120 100 80 RIMIN=25kΩ 60 40 20 -40 -20 0 20 40 60 80 o Temperature ( C) Figure 35. End-of-charge Current vs TA VAC=5.0 V or VUSB=5.0 V 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 13 FUNCTIONAL DESCRIPTION INTRODUCTION FUNCTIONAL DESCRIPTION INTRODUCTION The 34676 is a dual 28 V input charger, with 4.85 V regulated voltage output optimized for smart handheld devices. Many smart handheld applications require frequent data exchange between the device and the personal computer via a USB port. It is convenient that the device charges the Li-Ion battery by taking advantage of the 500 mA output current from the USB port, while exchanging the data. In the meantime, the handheld device also needs to be able to charge at a faster rate, when using an AC/DC adapter with higher than 500 mA output current capability. Such applications require a charger that can select one of the two power sources, and charge at a user desired current rate. The 34676 is optimized for such applications. The 34676 requires only four external capacitors and three resistors to build a fully functional charger for space-limited applications, such as PDAs, cell phones, and digital still cameras. Its ultra high voltage accuracy (±0.4%) and temperature limited charging current, offer additional battery safety during charging. Two external resistors, RIUSB and RISET, set the CC-mode current of the USB charger and the CC-mode current of the AC charger respectively. Both the USB charge current and the AC charge current can be monitored during the whole charge cycle, by measuring the voltage across RIUSB and RISET. For a deeply discharged battery with a voltage lower than 2.7 V, the charger preconditions the battery with 20% of the corresponding CC-mode current. The end-of-charge (EOC) current is set by an external resistor, RIMIN. The linear regulator provides 4.85 V with 45 mA (USBOUT) current capability. The output is turned on when the voltage of the USB input power supply is above the POR threshold but lower than the OVP threshold. The linear regulator is independent. It is not related to any signals of the charger including the enable input pin. Two indication outputs (PPR, CHG) make it easy to report the input power status and the charge status to MCUs or users via LEDs. FUNCTIONAL PIN DESCRIPTION AC INPUT SUPPLY (AC) END-OF-CHARGE CURRENT SETTING (IMIN) Power input from an AC/DC adapter. Bypass to ground with a 1.0 μF capacitor. The end-of-charge current is set by connecting a resistor, RIMIN, between this pin to ground. Both the AC charger and the USB charger have the same EOC current value. USB INPUT SUPPLY (USB) Power input from a USB port. Bypass to ground with a 1.0 μF capacitor. POWER PRESENT INDICATOR (PPR) Open-drain output to indicate the input power status. When both the AC and the USB input voltages are under the power-on-reset threshold voltage, or above the over-voltage protection threshold voltage, the PPR outputs a highimpedance. In any other conditions, the PPR outputs a low voltage. CHARGE STATUS INDICATOR (CHG) Open-drain output to indicate the charge status. The output is low when the 34676 is charging until the EOC conditions are reached. CHARGER SELECTION (USBEN) Logic input. This pin selects the AC charger or the USB charger. When driven to low, the AC charger is selected. When driven to high, the USB charger is selected. This pin is internally pulled to ground by a weak current source. The input is equivalent to low when this pin is floating. USB CHARGER CC-MODE CURRENT SETTING AND CHARGE CURRENT MONITOR (IUSB) The CC-mode current of the USB charger is set by connecting a resistor, RIUSB, between this pin and ground. When the USB charger is charging in the constant-current mode, the voltage at this pin is 1.0 V. The voltage reduces proportionally as the charge current reduces in the constantvoltage mode. During the whole charge cycle, the voltage at this pin can be used to monitor the charge current using the following equation: V IUSB I BAT = ---------------- ⋅ I USB 1.0V equ.1 where IBAT is the actual charge current, VIUSB is the voltage at the IUSB pin and IUSB is the CC-mode current of the USB charger programmed by the RIUSB. When this pin is floating, the CC-mode current of the USB charger is set to a default value of 400 mA. GROUND (GND) Ground. 34676 14 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DESCRIPTION FUNCTIONAL PIN DESCRIPTION AC CHARGER CC-MODE CURRENT SETTING AND CHARGE CURRENT MONITOR (ISET) The CC-mode current of the AC charger is set by connecting a resistor, RISET, between this pin and ground. When the AC charger is charging in the constant-current mode, the voltage at this pin is 1.0 V. The voltage reduces proportionally as the charge current reduces in the constantvoltage mode. During the whole charge cycle, the voltage at this pin can be used to monitor the charge current using the following equation: V ISET I BAT = --------------- ⋅ I AC 1.0V equ.2 where IBAT is the actual charge current, VISET is the voltage at the ISET pin and IAC is the CC-mode current of the AC charger programmed by the RISET. USB REGULATOR OUTPUT (USBOUT) The USB regulator output pin. The USB linear regulator is powered by the USB input. The output voltage is 4.85 V and the output current capability is 45 mA. The USB regulator is enabled when the USB input voltage is between the POR and the OVP thresholds. Bypass to ground with a 0.1 μF or higher capacitor. CHARGER OUTPUT (BAT) Charger output pin. Connect this pin to the battery being charged. Bypass to ground with a 1.0μF or higher capacitor. BATTERY DETECTION (BATDET) Battery detection input. This input has a threshold of 1.75 V. When the input voltage is lower than the threshold, the charger is enabled. An internal 4.0 μA pull-up current source pulls the voltage higher than the threshold if this pin is floating. EXPOSED PAD (EPAD) The exposed pad needs to be connected to GND. It must be soldered on a large ground plane on the PCB to enhance the thermal dissipation. 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 15 FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION MC34676 - Functional Block Diagram Integrated Supply Outputs Internal Supply & Reference Sensing & Control Power MOSFET VIN Monitor Charge Control Current Setting End of Charge Current Monitor VIN - BAT Comparator Die Temperature Feedback Battery Detection Linear Regulator Logic Logic Control & Status Indication Integrated Supply Sensing & Control Logic Outputs Figure 36. 34676 Functional Internal Block Diagram OUTPUTS SENSING & CONTROL POWER MOSFET VIN MONITOR The power MOSFET function contains two power MOSFETs that pass the charging current from the inputs (AC or USB) to the output (BAT). The input voltage monitor block monitors the AC input and the USB input voltages. If any input voltage is lower than its POR or higher than its OVP threshold, this block outputs a logic signal to disable the corresponding charger. LINEAR REGULATOR The linear regulator outputs a regulated 4.85 V from the USB input voltage with 45 mA (USBOUT) current capabilities. The regulator is only controlled by the power supply input. It is not controlled by the enable input or any other input signals. When the USB power supply input is powered, the Input Voltage Monitor and the Internal Supply blocks detect that the input voltage is greater than the POR rising threshold, and lower than the OVP threshold, the regulator is enabled and outputs 4.85 V. INTEGRATED SUPPLY INTERNAL SUPPLY & REFERENCE This block steps down the high input voltage to a lower voltage to power all the internal blocks. VIN – BAT COMPARATOR The input and battery voltage comparator monitors the voltage difference between the input voltage and the battery voltage. The input voltage has to be higher than the battery voltage for the charger to be enabled. If the voltage of the AC input or the USB input falls below the battery voltage, this block outputs a signal to disable the corresponding charger to prevent the leakage current from the battery to the input. CHARGE CONTROL The charge control block controls the gate voltage of the power MOSFETs to regulate the charge current, the battery voltage, or the die temperature. It can also completely turn off the power MOSFETs to stop the current flow between the input and the battery. DIE TEMPERATURE SENSE The die temperature sense block monitors the die temperature. Once the die temperature reaches the 34676 16 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION threshold temperature, this block tries to reduce the charge current to prevent further die temperature rise. CHARGE CURRENT SETTING AND CURRENT MONITOR This block sets the CC-mode charge current and monitors the actual charge current of both the AC charger and the USB charger during the whole charge cycle. END OF CHARGE (EOC) CURRENT SETTING The EOC current setting block sets the EOC current of both the AC charger and the USB charger. BATTERY DETECTION This block detects the connection status of the battery. It is also an enable input for the 34676. LOGIC LOGIC CONTROL AND STATUS INDICATION The logic control block determines the on and off of the charger, based on the signals from the Input Voltage Monitor block, the Internal Supply block, the Input and Battery Voltage Comparator block, the charger selection pin, and the external enable input pin. 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 17 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES The 34676 uses the standard charge profile with trickle mode, constant-current (CC) mode, and constant-voltage (CV) mode, as shown in Figure 37. Both the CC-mode and the CV-mode are called fast charge mode. Figure 40 shows the complete charge cycle state diagram. When the input voltage rises above the internal power-onreset threshold and is less than its OVP threshold, the PPR pin outputs a logic low level to indicate the power supply presence. The charger starts to verify the enable input (BATDET input). If it is enabled, the charger will start with the trickle mode until the battery voltage is above 2.7 V. The CHG pin turns to logic low level at the beginning of the trickle mode. If the battery voltage is unable to rise due to a battery failure, the charging will remain in the trickle-charge mode. When the battery voltage reaches the 2.7 V threshold, the 34676 softly changes to the CC-mode. The soft transition minimizes the input voltage drop and reduces the requirement of the input decoupling capacitance. When the battery voltage reaches 4.2 V, the 34676 enters the CVmode and regulates the output voltage at 4.2 V. The charge current decreases gradually in the CV-mode. When the current drops to the EOC current threshold, the 34676 outputs a logic high level at the CHG pin, to indicate that the charger has entered into the charge completion mode. After the charge is completed, the 34676 continues to regulate the output to 4.2 V. If a load is in parallel with the battery, the charger continues to output the current to the load even the charge is completed. When the battery voltage is below the recharge voltage threshold of 4.10 V, the 34676 returns to the fast charge mode and indicates a low signal at the CHG pin. When one of the following conditions happen, the chargers stop charging and enter disable mode. 1. VIN > VOVP 2. VIN -VBAT < VOS 3. The voltage at BATDET pin is higher than 1.75 V where VIN can be either the AC or the USB input voltage. . Trickle Constant Current Constant Voltage Charge Voltage 100mV Charge Current ITRKL IEOC TIME CHG TIME Figure 37. Typical Charge Cycle 34676 18 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES DETAILED FUNCTIONAL DEVICE OPERATION DC 28V INPUT AC CHARGE CURRENT SETTING The 34676 consists of two power MOSFETs, as shown in Figure 38, that act as power source selection devices and pass the charge current from input to output. Both inputs are capable of withstanding up to 28 V DC input. The charger only charges when the input voltage is in a power-good range. An external reference resistor between the ISET pin and ground sets the CC-mode charge current of the AC charger by the following equation: 3950 equ.3 I AC = --------------R ISET AC USB BAT Analog Control Figure 38. Dual Internal Power MOSFETs The input voltage is defined as being in a power-good range when satisfying all following three conditions: 1. VIN > VPOR 2. VIN -VBAT > VOS 3. VIN < VOVP where VIN can be either the AC or the USB input voltage. Only one of the two inputs is selected as the power source to charge the battery at a time. The AC input is selected if the USBEN voltage is a low logic level, and the USB input is selected when the USBEN voltage is high logic level. DC INPUT INDICATOR The 34676 uses PPR pin to indicate the DC input power presence. When both the AC and the USB input voltages are under the power-on-reset threshold voltage, or above the over-voltage protection threshold voltage, the PPR outputs high-impedance. In any other conditions, the PPR outputs low voltage. The PPR output is only controlled by the input voltage. All other functions, such as the enable signal and the Input-and-Battery-Voltage Comparator, do not affect the PPR output. where RISET is the resistance between the ISET pin and ground. In addition, the current out of the ISET pin is also proportional to the charge current. The system may measure the ISET pin voltage to monitor the actual charge current, as given in equ.2, during the whole charging cycle. USB CHARGE CURRENT SETTING An external reference resistor between the IUSB pin and ground sets the CC-mode charge current of the USB charger by the following equation: 1975 equ.4 I USB = --------------R IUSB where RIUSB is the resistance between the IUSB pin and ground. In addition, the current out of the IUSB pin is also proportional to the charge current. The system may measure the IUSB pin voltage to monitor the actual charge current, as given in equ.1, during the whole charging cycle. CHARGE CURRENT LIMIT The charge current is limited by multiple factors. When the voltage difference between the input and the battery (VAC -VBAT or VUSB -VBAT) is low, (VAC -VBAT)/ RDS(ON)AC or (VUSB -VBAT)/RDS(ON)USB may be less than the corresponding programmed CC-mode current. The charge current is, in this case, limited by (VAC -VBAT)/RDS(ON)AC or (VUSB -VBAT)/RDS(ON)USB. When the voltage difference between the input and the battery is too high, the large power dissipation may lead to the thermal-foldback operation due to the die-temperature regulation. The charge current is reduced to prevent further temperature rise (See the Thermal current foldback section for more information). OVER-VOLTAGE PROTECTION (OVP) Both the USB charger and the AC charger have an OVP threshold as specified in the Static Electrical Characteristics table. When an input voltage is higher than its OVP threshold, the input voltage does not meet the power-good condition, and cannot be selected as the input power source. However, the other input power source may still be in the power-good range and charge the battery. The PPR pin outputs highimpedance if both inputs are above its OVP threshold. 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 19 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES INPUT AND BATTERY VOLTAGE COMPARATOR LIVE SWITCHING BETWEEN CHARGERS The input and battery voltage comparator monitors the voltage difference between the input voltage and the battery voltage, as shown in Figure 2. The input voltage has to be higher than the battery voltage, for the charger to be enabled. If the input voltage falls below the battery voltage, this block outputs a signal to disable the charger, to prevent the leakage current from the battery to the input. Due to the intrinsic input offset voltage of the comparators, a small positive voltage, VOS, is added. Thus the power MOSFET can be turned on only when the input voltage is higher than the battery voltage by VOS. On the other hand, the added VOS guarantees that the power MOSFET is turned off when the input voltage is lower than the battery voltage. When switching from one charger to the other in the middle of a charge cycle, the newly turned on charger will start a new charge cycle. When both the AC and the USB inputs are powered, switching the USBEN signal from low to high will force the charging to switch from the AC charger to the USB charger, and switching the USBEN signal from high to low will force the charging to switch form the USB charger to the AC charger. Every time when the switching happens, a new charge cycle will be initialized. CHARGER SELECTION INPUT The USBEN selects either the AC or the USB charger. When the USBEN is driven to a low logic level, the AC charger is selected. When the USBEN is driven to a highlogic level, the USB charger is selected. The USBEN is internally pulled low by a weak current source. BATTERY DETECTION INPUT The battery detection input, BATDET, detects the connection of the battery, and is an enable input for the charger. The BATDET comparator has a threshold of 1.75 V (typical). When this pin is driven below this threshold, the charger is enabled. When driven higher than the 1.75 V threshold, the charger is disabled. The BATDET pin is internally pulled up by a 4.0 μA current source. The BATDET input does not affect the PPR signal. THERMAL CURRENT FOLDBACK An internal thermal feedback loop begins to reduce the charge current when the die temperature reaches 110oC, to prevent further temperature rise. This feature protects the 34676 from over-temperature failure, and allows the user to push the limits of the power handling capability of a given circuit board, without the risk of damaging the 34676. The charge current can be set according to the typical (not the worst case) ambient temperature, with the assurance that the charger will automatically reduce the current in worst-case conditions. REGULATED OUTPUT The 34676 has one regulated output, USBOUT. The USBOUT is powered by the USB input. Its regulated output voltage is 4.85 V. When the USB input voltage is below the rising POR threshold, or higher than the OVP threshold, the USBOUT output voltage is zero volts. When the USB input voltage is above the rising POR threshold, and before the linear regulator enters regulation, the output tracks the input voltage with a possible dropout voltage, caused by the on resistance of the pass switch. When the input voltage is higher than the 4.85 V, but lower than the OVP threshold, the output is regulated to 4.85 V. The waveform of the voltage-regulated output vs. the input voltage is summarized in Figure 39. VUSB VOVPR VPORR VOVPF 4.85V VUSBOUT VPORF Figure 39. Voltage Regulated Output vs. Input Voltage The regulated output is only controlled by the input voltage, and independent on the enable or the other inputs. When the USB input is powered, the USBOUT will output 4.85 V. 34676 20 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES STATE DIAGRAM Both AC and USB inputs below POR threshold PWR OFF Charger: OFF PPR: H VUSB > VPOR or VAC > VPOR Not Enabled Anytime charger disabled EN VERIFICATION Charger: OFF PPR: L OV fault removed Power good POR Charger: OFF PPR: L Enabled TRICKLE CHARGE OV FAULT Charger: OFF PPR: H CHG: H Charger: ON PPR: L CHG: L VBAT > VTRK Anytime an OV Fault occurs VBAT drops below VTRK FAST CHARGE Charger: ON PPR: L CHG: L VBAT > VRCH and IBAT < IEOC VBAT < VRCH CHARGE COMPLETE Charger: ON PPR: L CHG: H Figure 40. Charge Cycle State Diagram 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 21 TYPICAL APPLICATIONS APPLICATION INFORMATION TYPICAL APPLICATIONS APPLICATION INFORMATION INPUT CAPACITOR THERMAL CONSIDERATIONS The input capacitor is used to minimize the input voltage transient that may cause instability when the input voltage is near VBAT+VOS. Typically a 1.0 µF X5R ceramic capacitor is sufficient for most applications. The 34676 is available in a 3x3 thermally-enhanced UDFN package. A careful thermal design must be considered. The thermal pad needs to be well soldered to a large copper ground plane on the component layer. If the component layer is space limited and does not allow a large copper plane, the thermal pad needs to be connected to other layers through a via array. This increases the actual charge current capability of the 34676. OUTPUT CAPACITOR For stable operation, an X5R ceramic capacitor of 1.0µF minimum value is needed in parallel with the battery. Depending on the load transient current, a larger capacitance may be required. DUAL-INPUT CHARGER Figure 41 shows a typical application using the 34676. C1 and C2 are typically 1.0 μF/X5R/16 V ceramic capacitors. C3 is a typically a 0.1 μF/X5R/6.3 V ceramic capacitor. C4 usually is a combination of multiple capacitors that are connected to the BAT bus. The charger will be stable with a minimum of a 1.0 μF/X5R/6.3 V ceramic capacitor when a battery is connected. When no battery is connected, a minimum of a 10 mA load current is required for the charger output to be stable in CV phase. All connections to the MCU are optional. The voltage output of the ISET and the IUSB pin can be monitored by an analog-to-digital input of the MCU, for charge current measurement. The USBEN pin requires no pull-up resistors. The MCU can choose the AC charger or the USB charger, by controlling the USBEN pin voltage. Since the BATDET sources 6.0 μA (maximum) of current and has a 1.65 V (minimum) battery detection threshold, a pull-down resistor less than 275 kΩ should be attached at BATDET, to enable the charger. If the battery pack doesn’t have an ID resistor inside, an external resistor is required. CC-MODE CURRENT SETTING The CC-mode current of the USB charger, or the AC charger, can be set by external resistors, RIUSB and RISET. A 1% accuracy resistor is recommended to guarantee 5% and 15% CC-mode current accuracy for the AC charger and the USB charger respectively. EOC CURRENT SETTING The EOC current can be set by the external resistor, RIMIN. A 1% accuracy resistor is recommended to guarantee the EOC current accuracy. DROPOUT VOLTAGE If the input voltage is too low, it may not maintain the programmed CC-mode current, due to the voltage dropout over the power MOSFET. The worst case of RDS(ON) is 500 mΩ for the AC charger and 1000 mΩ for the USB charger. The input voltage should be higher than VBAT + IAC x 500 mΩ for the AC charger, and VBAT + IUSB x 1000 mΩ for the USB charger, to guarantee the programmed CC-mode current. MC34676B BAT BATDET USBOUT AC C1 USB C2 GND IMIN IUSB C3 VDDIO PPR ISET C4 USBEN CHG MCU RIMIN RIUSB RISET USB AC Figure 41. Dual-input Charger of the MC34676 34676 22 Analog Integrated Circuit Device Data Freescale Semiconductor TYPICAL APPLICATIONS PACKAGE DIMENSIONS PACKAGE DIMENSIONS For the most current package revision, visit www.freescale.com and perform a keyword search using the “98A” listed below. EP SUFFIX 12-PIN 98ASA10814D REVISION 0 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 23 TYPICAL APPLICATIONS PACKAGE DIMENSIONS EP SUFFIX 12-PIN 98ASA10814D REVISION 0 34676 24 Analog Integrated Circuit Device Data Freescale Semiconductor TYPICAL APPLICATIONS PACKAGE DIMENSIONS EP SUFFIX 12-PIN 98ASA10814D REVISION 0 34676 Analog Integrated Circuit Device Data Freescale Semiconductor 25 REVISION HISTORY REVISION HISTORY REVISION 1.0 DATE 10/2007 DESCRIPTION OF CHANGES • Initial Release 34676 26 Analog Integrated Circuit Device Data Freescale Semiconductor How to Reach Us: Home Page: www.freescale.com Web Support: http://www.freescale.com/support USA/Europe or Locations Not Listed: Freescale Semiconductor, Inc. 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