ACT8828

Active-Semi FEATURES • ActivePathTM Li+ Charger with System Power Selection ACT8828 Rev 3, 24-Sep-09 Six Channel ActivePathTM Power Management IC GENERAL DESCRIPTION The patent-pending ACT8828 is a complete, cost effective, highly-efficient ActivePMUTM power management solution that is ideal for a wide range of high performance portable handheld applications such as personal navigation devices (PNDs). This device integrates the ActivePath complete battery charging and management system with four power supply channels. The ActivePath architecture automatically selects the best available input supply for the system. If the external input source is not present or the system load current is more than the input source can provide, the ActivePath supplies additional current from the battery to the system. The charger is a complete, thermallyregulated, stand-alone single-cell linear Li+ charger that incorporates an internal power MOSFET. REG1, REG2, and REG3 are three independent, fixed-frequency, current-mode step-down DC/DC converters that output 1.3A, 1.0A, and 0.55A, respectively. REG4 is a fixed-frequency, step-up DC/DC converter that safely and efficiently biases strings of up to 7 white-LEDs (up to a total of 21 LEDs) for display backlight applications. Finally, an I2C serial interface provides programmability for the DC/DC converters. The ACT8828 is available in a tiny 5mm × 5mm 40pin Thin-QFN package that is just 0.75mm thin. • Four Integrated Regulators: − 1.3A High Efficiency Step-Down DC/DC − 1.0A High Efficiency Step-Down DC/DC − 0.55A High Efficiency Step-Down DC/DC − 30V Step-Up DC/DC for up to 7s × 3p WLEDs • • • • I2CTM Serial Interface Minimal External Components Compatible with USB or AC-Adapter Charging 5×5mm, Thin-QFN (TQFN55-40) Package − Only 0.75mm Height − RoHS Compliant APPLICATIONS • Personal Navigation Devices • Portable Media Players • Smart Phones SYSTEM BLOCK DIAGRAM CHG_IN CHGLEV DCCC ISET ACIN nSTAT nPBIN nIRQ nRSTO SCL SDA ON1 ON2 ON3 ON4 VSEL System Control Li+ Battery Programmable Up to 1A VSYS REG1 Step-Down DC/DC REG2 Step-Down DC/DC REG3 Step-Down DC/DC REG4 Step-Up DC/DC OUT1 Adjustable, or 0.8V to 4.4V Up to 1.3A OUT2 Adjustable, or 0.8V to 4.4V Up to 1.0A OUT3 Adjustable, or 0.8V to 4.4V Up to 0.55A OUT4 Up to 30V 7s x 3p WLEDs ActivePathTM & Single-Cell Li+ Battery Charger ACT8828 Active PMU TM Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -1- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi TABLE OF CONTENTS ACT8828 Rev 3, 24-Sep-09 GENERAL INFORMATION ..........................................................................................P. 01 Functional Block Diagram ...................................................................................................... p. 03 Ordering Information .............................................................................................................. p. 04 Pin Configuration .................................................................................................................... p. 04 Pin Descriptions ..................................................................................................................... p. 05 Absolute Maximum Ratings.................................................................................................... p. 07 SYSTEM MANAGEMENT ...........................................................................................P. 08 Register Descriptions ............................................................................................................. p. 08 I2C Interface Electrical Characteristics ................................................................................... p. 09 Electrical Characteristics ........................................................................................................ p. 10 Register Descriptions ............................................................................................................. p. 11 Typical Performance Characteristics...................................................................................... p. 12 Functional Description ............................................................................................................ p. 13 STEP-DOWN DC/DC CONVERTERS ..........................................................................P. 17 Electrical Characteristics ........................................................................................................ p. 17 Typical Performance Characteristics...................................................................................... p. 20 Register Descriptions ............................................................................................................. p. 22 Functional Description ............................................................................................................ p. 28 STEP-UP DC/DC CONVERTERS ................................................................................P. 31 Electrical Characteristics ........................................................................................................ p. 31 Typical Performance Characteristics...................................................................................... p. 32 Register Descriptions ............................................................................................................. p. 33 Functional Description ............................................................................................................ p. 35 ActivePathTM CHARGER .............................................................................................P. 37 Electrical Characteristics ........................................................................................................ p. 37 Typical Performance Characteristics...................................................................................... p. 39 Functional Description ............................................................................................................ p. 41 PACKAGE INFORMATION ..........................................................................................P. 49 Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -2- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi FUNCTIONAL BLOCK DIAGRAM BODY SWITCH ACT8828 Rev 3, 24-Sep-09 (Optional) AC Adaptor USB Active-Semi ACT8828 BODY SWITCH CHG_IN Up to 12V ACIN VSYS System Supply BAT DCCC VSYS ActivePath Control CURRENT SENSE 100µA Li+ Battery + TH nSTAT CHARGE STATUS VOLTAGE SENSE PRECONDITION 2.9V 110°C BTR ISET VSYS CHGLEV OUT1 nRSTO Charge Control THERMAL REGULATION VP1 To VSYS SW1 REG1 OUT1 OUT1 GP1 VP2 nIRQ SW2 REG2 OUT2 OUT2 GP2 VP3 VSYS nPBIN PUSH BUTTON OUT1 To VSYS SCL SDA ON1 ON2 ON3 ON4 VSEL REFBP GA EP REG4 System Control REG3 To VSYS SW3 OUT3 OUT3 GP3 SW4 OVP4 FB4 GP4 To VSYS OUT4 7s x 3p WLEDs Reference Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -3- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ORDERING INFORMATION PART NUMBER ACT8828QJ1D2-T ACT8828QJ250-T ACT8828QJ3B9-T ACT8828 Rev 3, 24-Sep-09 VOUT1/VSTBY1 1.2V/1.2V 3.3V/3.3V 1.2V/1.2V VOUT2/VSTBY2 1.9V/1.9V 1.85V/1.85V 1.8V/1.8V VOUT3/VSTBY3 3.3V/3.3V 1.25V/1.25V 3.3V/3.3V CONTROL SEQUENCE Sequence A Sequence B Sequence C PACKAGING DETAILS ACT8828QJ###-T PACKAGE TQFN55-40 PINS 40 TEMPERATURE RANGE -40°C to +85°C PACKING TAPE & REEL : All Active-Semi components are RoHS Compliant and with Pb-free plating unless specified differently. The term Pb-free means semiconductor products that are in compliance with current RoHS (Restriction of Hazardous Substances) standards. : To select VSTBYx as a output regulation voltage of REGx, tie VSEL to VSYS or a logic high. : Refer to the Control Sequence section for more information. PIN CONFIGURATION TOP VIEW CHGLEV nRSTO REFBP nSTAT nIRQ SW4 ON4 ON2 GP4 GA TH DCCC BTR ACIN BAT BAT VSYS VSYS CHG_IN ISET OVP4 FB4 VP3 Active-Semi ACT8828 SW3 GP3 OUT3 nPBIN SDA EP SCL ON3 VSEL ON1 Thin - QFN (TQFN55-40) OUT2 VP2 SW2 GP2 GP1 SW1 VP1 OUT1 Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -4- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi PIN DESCRIPTIONS PIN 1 ACT8828 Rev 3, 24-Sep-09 NAME TH DESCRIPTION Temperature Sensing Input. Connect to battery thermistor. TH is pulled up with a 100µA current internally. See the Battery Temperature Monitoring section for more information. Dynamic Charging Current Control. Connect a resistor to set the dynamic charging current control point. A internal 100µA current source sets up a voltage that is used to compare with VSYS and dynamically scale the charging current to maintain VSYS regulation. See the Dynamic Charge Current Control section for more information. Safety Timer Program Pin. The resistance between this pin and GA determines the timers timeout values. See the Charging Safety Timers section for more information. AC Adaptor Detect. Detects presence of a wall adaptor and automatically adjusts the charge current to the maximum charge current level. Do not leave ACIN floating. Battery Charger Output. Connect this pin directly to the battery anode (+ terminal) System Output Pin. Bypass to GA with a 10µF or larger ceramic capacitor. Power Input for the Battery Charger. Bypass CHG_IN to GA with a capacitor placed as close to the IC as possible. The battery charger are automatically enabled when a valid voltage is present on CHG_IN. Charge Current Set. Program the maximum charge current by connecting a resistor (RISET) between ISET and GA. See the Charger Current Programming section for more information. Step-Down DC/DCs Output Voltage Selection. Drive to logic low to select default output voltage. Drive to logic high to select secondary output voltage. See the Output Voltage Selection Pin section for more information. Independent Enable Control Input for REG1. Drive ON1 to VSYS or to a logic high for normal operation, drive to GA or a logic low to disable REG1. Do not leave ON1 floating. Output Feedback Sense for REG2. Connect this pin directly to the output node to connect the internal feedback network to the output voltage. Power Input for REG2. Bypass to GP2 with a high quality ceramic capacitor placed as close as possible to the IC. Switching Node Output for REG2. Connect this pin to the switching end of the inductor. Power Ground for REG2. Connect GA, GP1, GP2, GP3, and GP4 together at a single point as close to the IC as possible. Power Ground for REG1. Connect GA, GP1, GP2, GP3, and GP4 together at a single point as close to the IC as possible. Switching Node Output for REG1. Connect this pin to the switching end of the inductor. Power Input for REG1. Bypass to GP1 with a high quality ceramic capacitor placed as close as possible to the IC. Output Feedback Sense for REG1. Connect this pin directly to the output node to connect the internal feedback network to the output voltage. Enable Control Input for REG3. Drive ON3 to a logic high for normal operation, drive to GA or a logic low to disable REG3. Do not leave ON3 floating. Clock Input for I2C Serial Interface. Data Input for I2C Serial Interface. Data is read on the rising edge of SCL. 2 DCCC 3 4 5, 6 7, 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 BTR ACIN BAT VSYS CHG_IN ISET VSEL ON1 OUT2 VP2 SW2 GP2 GP1 SW1 VP1 OUT1 ON3 SCL SDA Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -5- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi PIN DESCRIPTIONS CONT’D PIN 24 25 26 27 28 29 30 31 32 33 ACT8828 Rev 3, 24-Sep-09 NAME nPBIN OUT3 GP3 SW3 VP3 FB4 OVP4 GP4 SW4 nSTAT DESCRIPTION Master Enable Input. Drive nPBIN to GA through a 100kΩ resistor to enable the IC, drive nPBIN directly to GA to assert a Hard-Reset condition. Refer to the System Startup & Shutdown section for more information. nPBIN is internally pulled up to VSYS through a 50kΩ resistor. Output Feedback Sense for REG3. Connect this pin directly to the output node to connect the internal feedback network to the output voltage. Power Ground for REG3. Connect GA, GP1, GP2, GP3, and GP4 together at a single point as close to the IC as possible. Switching Node Output for REG3. Connect this pin to the switching end of the inductor. Power Input for REG3. Bypass to GP3 with a high quality ceramic capacitor placed as close as possible to the IC. Feedback Sense for REG4. Connect this pin to the LED string current sense resistor to sense the LED current. Over-Voltage Protection Input for REG4. Connect this pin to the output node through a 10kΩ resistor to sense and prevent over-voltage conditions. Power Ground for REG4. Connect GP4 directly to a power ground plane. Connect GA, GP1, GP2, GP3, and GP4 together at a single point as close to the IC as possible. Switching Node Output for REG4. Connect this pin to the switching end of the inductor. Active-Low Open-Drain Charger Status Output. nSTAT has a 5mA (typ) current limit, allowing it to directly drive an indicator LED without additional external components. To generate a logic-level output, connect nSTAT to an appropriate supply voltage (typically VSYS) through a 10kΩ or greater pull-up resistor. See the Charge Status Indication section for more information. Independent Enable Control Input for REG2. Drive ON2 to a logic high for normal operation, drive to GA or a logic low to disable REG2. Do not leave ON2 floating. Analog Ground. Connect GA directly to a quiet ground node. Connect GA, GP1, GP2, GP3, and GP4 together at a single point as close to the IC as possible. Reference Noise Bypass. Connect a 0.01µF ceramic capacitor from REFBP to GA. This pin is discharged to GA in shutdown. Independent Enable Control Input for REG4. Drive ON4 to a logic high for normal operation, drive to GA or a logic low to disable REG4. Do not leave ON4 floating. Open-Drain Reset Output. nRSTO asserts low whenever REG1 is out of regulation, and remains low for 260ms (typ) after REG1 reaches regulation. Open-Drain Interrupt Output. nIRQ asserts any time nPBIN is asserted or an unmasked fault condition exists. When asserted by nPBIN, nIRQ automatically de-asserts when nPBIN is released. When asserted by an unmasked fault condition, nIRQ remains asserted until the ACT8828 is polled by the microprocessor. See the nIRQ Output section for more information. Charging State Select Input. When ACIN = 0 charge current is internally set; Drive CHGLEV to a logic-high for high-current USB charging mode (maximum charge current is 500mA), drive CHGLEV to a logic-low for lowcurrent USB charging mode (maximum charge current is 100mA). When ACIN = 1 charge current is externally set by RISET; Drive CHGLEV to a logic-high to for high -current charging mode (ICHG = K x 1000/RISET(mA) where K = 640), drive CHGLEV to a logic-low for low-current charging mode (ICHG = K x 500/RISET(mA) where K = 640). Do not leave CHGLEV floating. Exposed Pad. Must be soldered to ground on the PCB. 34 35 36 37 38 ON2 GA REFBP ON4 nRSTO 39 nIRQ 40 CHGLEV EP EP Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. -6- www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ABSOLUTE MAXIMUM RATINGS PARAMETER CHG_IN to GA t < 1ms and duty cycle VUVLO VCHG_IN > VBAT + 120mV , VCHG_IN > VUVLO Charger disabled, ISYS = 0mA 3.6 3.8 0.8 6.8 350 20 4.0 CHG_IN Supply Current 50 120 1.8 0.4 200 µA mA CHG_IN to VSYS On-Resistance CHG_IN to VSYS Current Limit IVSYS = 100mA ACIN = VSYS ACIN = GA, CHGLEV = GA ACIN = GA, CHGLEV = VSYS 1.5 85 400 0.6 3 105 500 Ω A mA 2 95 450 VSYS AND DCCC REGULATION VSYS Regulated Voltage DCCC Pull-Up Current IVSYS = 10mA VCHG_IN > VBAT + 120mV, Hysteresis = 50mV 4.4 92 4.6 100 4.8 108 V µA nSTAT OUTPUT nSTAT Sink current nSTAT Output Low Voltage nSTAT Leakage Current VnSTAT = 2V InSTAT = 1mA VnSTAT = 4.2V 3 5 7 0.4 1 mA V µA ACIN AND CHGLEV INPUTS CHGLEV Logic High Input Voltage CHGLEV Logic Low Input Voltage CHGLEV Leakage Current ACIN Logic High Input Voltage ACIN Logic Low Input Voltage ACIN Leakage Current VACIN = 4.2V VCHGLEV = 4.2V 1.4 0.4 1.4 0.4 V V µA V V µA 1 1 92 0.485 2.47 100 0.500 2.52 30 - 37 - TEMPERATURE SENSE COMPARATOR TH Pull-Up Current VTH Upper Temperature Voltage Threshold (VTHH) VTH Lower Temperature Voltage Threshold (VTHL) VTH Hysteresis Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. VCHG_IN > VBAT + 120mV, Hysteresis = 50mV Hot Detect NTC Thermistor Cold Detect NTC Thermistor Upper and Lower 108 0.525 2.57 µA V V mV www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath ELECTRICAL CHARACTERISTICS CONT’D (VCHG_IN = 5V, TA = 25°C, unless otherwise specified.) ACT8828 Rev 3, 24-Sep-09 TM CHARGER PARAMETER CHARGER BAT Reverse Leakage Current BAT to VSYS On-Resistance ISET Pin Voltage TEST CONDITIONS VCHG_IN = 0V, VBAT = 4.2V, IVSYS = 0mA MIN TYP 5 80 MAX UNIT µA mΩ Fast Charge Precondition TA = -20°C to 70°C TA = -40°C to 85°C ACIN = VSYS, CHGLEV = VSYS ACIN = VSYS, CHGLEV = GA 4.179 4.170 -10% -16% -10% 1.02 0.12 4.2 4.221 4.230 ISET1 50%ISET +10% +16% V V Battery Regulation Voltage Charge Current VBAT = 3.5V ACIN = GA, CHGLEV = VSYS Smallest (450mA or +10% ISET) Smallest (90mA or ISET) 12%ISET 12%ISET 12%ISET Smallest (90mA or 12%ISET) +10% mA ACIN = GA, CHGLEV = GA ACIN = VSYS, CHGLEV = VSYS ACIN = VSYS, CHGLEV = GA Precondition Charge Current VBAT = 2.5V ACIN = GA, CHGLEV = VSYS ACIN = GA, CHGLEV = GA Precondition Threshold Voltage VBAT Voltage Rising -10% mA 2.75 2.85 100 2.95 V mV Precondition Threshold Hysteresis VBAT Voltage Falling ACIN = VSYS, CHGLEV = VSYS End-of-Charge Current Threshold VBAT = 4.2V ACIN = VSYS, CHGLEV = GA ACIN = GA, CHGLEV = VSYS ACIN = GA, CHGLEV = GA Charge Restart Threshold BTR Scale Factor Precondition Safety Timer Fast Charge Safety Timer RBTR = 47kΩ, tPRCHG = 0.24 × RBTR(Ω)/180(min) RBTR = 47kΩ, tCHG = 0.24 × RBTR(Ω)/60(min) VVSYS - VBAT, VBAT Falling -10% -10% -10% -10% 150 10%ISET 10%ISET 5%ISET 5%ISET 170 0.24 1 3 +10% +10% +10% +10% 190 mV s/Ω hr hr mA THERMAL REGULATION Thermal Regulation Threshold : ISET = 640 x (1V/RISET) 100 145 °C Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 38 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath TYPICAL PERFORMANCE CHARACTERISTICS (VCHG_IN = 5V, TA = 25°C, unless otherwise specified.) SYS Output Voltage vs. DC Voltage 4.8 4.7 4.25 ACT8828-016 ACT8828 Rev 3, 24-Sep-09 TM CHARGER SYS Voltage vs. SYS Current ACT8828-017 SYS Voltage (V) 4.5 4.4 4.3 4.2 4.1 4.0 0 2 4 6 8 10 12 14 No Load ACIN = 1 CHGLEV = 1 ISYS = 10mA SYS Voltage (V) 4.6 4.15 4.05 3.95 3.85 VBAT = 4.2V 0 1000 2000 3000 3.75 CHG_IN Voltage (V) SYS Current (mA) Charger Current vs. Battery Voltage 100 ACT8828-018 Charger Current vs. Battery Voltage (USB Mode) 500 450 Battery Voltage Falling ACT8828-019 Charger Current (mA) Charger Current (mA) 80 VBAT Falling 400 350 300 250 200 150 100 50 0 0.0 60 Battery Voltage Rising 40 VBAT Rising 20 0 0 0.5 1.0 1.5 2.0 2.5 CHG_IN = 5V ISYS = 0 mA 100mA USB 3.0 3.5 4.0 4.5 CHG_IN = 5V ISYS = 0mA 500mA USB 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 Battery Voltage (V) Battery Voltage (V) Charger Current vs. Battery Voltage (AC Mode) 1200 1000 ACT8828-020 ISYS = 0mA Battery Voltage Falling Fast Charge Current vs. Ambient Temperature 1200 ACT8828-021 Fast Charger Current (mA) 1000 ACIN, CHGLEV = 11 800 ACIN, CHGLEV = 10 600 400 ACIN, CHGLEV = 01 200 0 ACIN, CHGLEV = 00 Charger Current (mA) 800 Battery Voltage Rising 600 400 200 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 -40 -20 0 20 40 60 80 100 120 140 Battery Voltage (V) Ambient Temperature (°C) Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 39 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (VCHG_IN = 5V, TA = 25°C, unless otherwise specified.) ACT8828 Rev 3, 24-Sep-09 TM CHARGER VAC Applied, CHGLEV = LOW ACT8828-022 CH1 CH2 CH1 CH2 CH3 450mA VAC Applied, CHGLEV = HIGH ACT8828-023 CH3 100mA CH4 CH4 CH1: VUSB, 2.00V/div CH2: VCHG_IN, 2.00V/div CH3: IBAT, 500mA/div CH4: VVAC, 2.00V/div TIME: 400µs/div CH1: VUSB, 2.00V/div CH2: VCHG_IN, 2.00V/div CH3: IBAT, 500mA/div CH4: VVAC, 2.00V/div TIME: 400µs/div VAC Removed, CHGLEV = LOW ACT8828-024 CH1 CH2 VAC Removed, CHGLEV = HIGH ACT8828-025 CH1 CH2 CH3 450mA CH3 100mA CH4 CH4 CH1: VUSB, 2.00V/div CH2: VCHG_IN, 2.00V/div CH3: IBAT, 500mA/div CH4: VVAC, 2.00V/div TIME: 400µs/div CH1: VUSB, 2.00V/div CH2: VCHG_IN, 2.00V/div CH3: IBAT, 500mA/div CH4: VVAC, 2.00V/div TIME: 400µs/div Battery Leakage Current vs. Battery Voltage 10 ACT8828-026 Battery Leakage Current (µA) 8 6 4 2 No CHG_IN CHGLEV = 0 4 5 00 1 2 3 Battery Voltage (V) Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 40 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath FUNCTIONAL DESCRIPTION General Description The ACT8828 incorporates Active-Semi's patentpending ActivePath architecture. ActivePath is a complete battery-charging and system powermanagement solution for portable hand-held equipment. This circuitry performs a variety of advanced battery-management functions, including automatic selection of the best available input supply, current-management to ensure system power availability, and a complete, high-accuracy (±0.5%), thermally regulated, full-featured singlecell linear Li+ charger with an integrated 12V power MOSFET. ACT8828 Rev 3, 24-Sep-09 TM CHARGER System Configuration Optimization ActivePath circuitry automatically detects the state of the input supply, the battery, and the system, and automatically reconfigures itself to optimize the power system. If the input supply is present, ActivePath powers the system in parallel with charging the battery, so that system power and charge current can be independently managed to satisfy all system power requirements. This allows the battery to charge as quickly as possible, while ensuring that the total system current does not exceed the capability of the input supply. If the input supply is not present, however, then ActivePath automatically configures the system to draw power from the battery. Finally, if the input is present and the system current requirement exceeds the capability of the input supply, such as under momentary peak-power consumption conditions, ActivePath automatically configures itself for maximum power capability by drawing system power from both the battery and the input supply. Battery Management Input Protection ActivePath includes a full-featured battery charger for single-cell Li-based batteries. This charger is a full-featured, intelligent, linear-mode, single-cell charger for Lithium-based cells, and was designed specifically to provide a complete charging solution with minimum system design effort. ActivePath Architecture A ctive-semi's patent-pending A ctivePath architecture performs three important functions: 1) Input Protection, 2) System Configuration Optimization, and 3) Battery-Management At the input of the ACT8828's ActivePath circuit is an internal, low-dropout linear regulator (LDO) that regulates the system voltage (VSYS). This LDO features a 12V power MOSFET, allowing the ActivePath system to withstand input voltages of up to 12V, and additionally includes a variety of other protection features, including current limit protection and input over-voltage protection. The ActivePath circuitry provides a very simple means of implementing a solution that safely operates within the current-capability limitations of a USB port while taking advantage of the high outputcurrent capability of an AC adapter, when available. ActivePath limits the total current drawn from the input supply to a value set by the ACIN input; when ACIN is driven to a logic-low ActivePath operates in “USB Mode” and limits the current to either 500mA (when CHGLEV is driven to a logic-high) or to 100mA (when CHGLEV is driven to a logic-low), and when ACIN is driven to a logic-high ActivePath operates in “AC-Mode” and limits the input current to 2A. In either case, ActivePath's DCCC circuitry, described below, allows the input overload protection to be adjusted to accommodate a wide range of input supplies. Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. The core of the ActivePath's charger is a CC/CV (Constant-Current/Constant-Voltage), linear-mode charge controller. This controller incorporates current and voltage sense circuitry, an internal 80mΩ power MOSFET, a full-featured statemachine that implements charge control and safety features, and circuitry that eliminates the reverseblocking diode required by conventional charger designs. This charger also features thermal-regulation circuitry that protects it against excessive junction temperature, allowing the fastest possible charging times, as well as proprietary input protection circuitry that makes the charger robust against input voltage transients that can damage other chargers. The charge termination voltage is highly accurate (±0.5%), and features a selection of charge safety timeout periods that protect the system from operation with damaged cells. Other features include pin-programmable fast-charge current and - 41 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D current-limited nSTAT outputs that can directly drive LED indicators or provide a logic-level status signal to the host microprocessor. ACT8828 Rev 3, 24-Sep-09 TM CHARGER Dynamic Charge Current Control (DCCC) The ACT8828's ActivePath charger features Dynamic Charge Current Control (DCCC) circuitry, which continuously monitors the input supply and prevents input overload conditions by dynamically adjusting the charge current to keep the input voltage from dropping below the DCCC voltage threshold. By default, the DCCC voltage threshold is set to 4.4V, but it may also be programmed by connecting a resistor from DCCC to GA, where the resistor has value given by the following equation: VDCCC = 2 × (IDCCC × RDCCC) (2) When ACIN is driven to a logic-low, the circuitry operates in “USB-Mode”, which maximum charge current setting of CHGLEV is driven to a logic-high, or CHGLEV is driven to a logic-low. The ACT8828's charge current summarized in the table below: Table 16: ACIN and CHGLEV Inputs Table ACIN CHGLEV CHARGE CURRENT ICHG (mA) 90mA or 12% ISET (Smallest one) 450mA or ISET (Smallest one) 50% × ISET ISET ActivePath enforces a 500mA, if 100mA, if settings are PRECONDITION CHARGE CURRENT ICHG (mA) 90mA or 12%ISET (Smallest one) 12% × ISET 12% × ISET 12% × ISET 0 0 1 1 0 1 0 1 Where RDCCC is the value of the external resistor, and IDCCC is the value of the current sourced from DCCC, typically 100μA. Charger Current Programming The ACT8828's ActivePath charger features a flexible charge current-programming scheme that combines the convenience of internal charge current programming with the flexibility of resistor based charge current programming. Current limits and charge current programming are managed as a function of the ACIN and CHGLEV pins, in combination with RISET, the resistance connected to the ISET pin. ACIN and CHGLEV Inputs Note that the actual charging current may be limited to a current that is lower than the programmed fast charge current due to the ACT8828’s internal thermal regulation loop. See the Thermal Regulation and Protection section for more information. Battery Temperature Monitoring The ACT8828 continuously monitors the temperature of the battery pack by sensing the resistance of its thermistor, and suspends charging if the temperature of the battery pack exceeds the safety limits. In a typical application, shown in Figure 7, the TH pin is connected to the battery pack's thermistor input. The ACT8828 injects a 100µA current out of the TH pin into the thermistor, so that the thermistor resistance is monitored by comparing the voltage at TH to the internal VTHH and VTHL thresholds of 0.5V and 2.5V, respectively. When VTH > VTHL or VTH < VTHH charging and the charge timers are suspended. When VTH returns to the normal range, charging and the charge timers resume. The net resistance from TH to G required to cross the threshold is given by: 100µA × RNOM × kHOT = 0.5V → RNOM × kHOT = 5kΩ 100µA × RNOM × kCOLD = 2.5V → RNOM × kCOLD = 25kΩ ACIN is a logic input that configures the current-limit of ActivePath's linear regulator as well as that of the battery charger. ACIN features a precise 1.25V logic threshold, so that the input voltage detection threshold may be adjusted with a simple resistive voltage divider. This input also allows a simple, lowcost dual-input charger switch to be implemented with just a few, low-cost components. When ACIN is driven to a logic high, the ActivePath operates in “AC-Mode” and the charger charges at the current programmed by RISET, ICHG = 1V/RISET × KISET (3) where KISET = 640 when CHGLEV is driven to a logic high, and K = 320 when CHGLEV is driven to a logic low. Innovative Power TM - 42 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D where RNOM is the nominal thermistor resistance at room temperature, and kHOT and kCOLD are the ratios of the thermistor's resistance at the desired hot and cold thresholds, respectively. Figure 7: Simple Configuration ACT8828 100µA + – ACT8828 Rev 3, 24-Sep-09 TM CHARGER requirements with very little design effort, but also provides flexibility when additional control over a design is required. Initial thermistor selection is accomplished by choosing one that best meets the following requirements: RNOM = 5kΩ/kHOT, and RNOM = 25kΩ/kCOLD where kHOT and kCOLD for a given thermistor can be found on its characteristic tables. VTHH TH + Li+ Battery Pack + – NTC VTHL – Taking a 0°C to 40°C application using a "curve 2" NTC for this example, from the characteristic tables one finds that kHOT and kCOLD are 0.5758 and 2.816, respectively, and the RNOM that most closely satisfies these requirements is therefore around 8.8kΩ. Selecting 10kΩ as the nearest standard value, calculate kCOLD and kHOT as: kCOLD = VTHL/(ITH × RNOM) = 2.5V/(100µA × 10kΩ) = 2.5 kHOT = VTHH/(ITH × RNOM) = 0.5V/(100µA × 10kΩ) = 0.5 Identifying these values on the curve 2 characteristic tables indicates that the resulting operating temperature range is 2°C to 44°C, vs. the design goal of 0°C to 40°C. This example demonstrates that one can satisfy common operating temperature ranges with very little design effort. Fix VTHH Design Procedure When designing with thermistors it is important to keep in mind that their nonlinear behavior typically allows one to directly control no more than one threshold at a time. As a result, the design procedure can change depending on which threshold is most critical for a given application. Most application requirements can be solved using one of three cases, 1) Simple solution 2) Fix VTHH, accept the resulting VTHL 3) Fix VTHL, accept the resulting VTHH The ACT8828 was designed to achieve an operating temperature range that is suitable for most applications with very little design effort. The simple solution is often found to provide reasonable results and should always be used first, then the design procedure may proceed to one of the other solutions if necessary. In each design example, we refer to the Vishay NTHS series of NTCs, and more specifically those which follow a "curve 2" characteristic. For more information on these NTCs, as well as access to the resistance/temperature characteristic tables referred to in the example, please refer to the Vishay website at http://www.vishay.com/thermistors. Simple Solution For demonstration purposes, supposing that we had selected the next closest standard thermistor value of 6.8kΩ in the example above, we would have obtained the following results: kCOLD = VTHL/(ITH × RNOM) = 2.5V/(100µA × 6.8kΩ) = 3.67 kHOT = VTHH/(ITH × RNOM) = 0.5V/(100µA × 6.8kΩ) = 0.74 which, according to the characteristic tables would have resulted in an operating temperature range of -6°C to 33°C vs. the design goal of 0°C to 40°C. In this case, one can add resistance in series with the thermistor to shift the range upwards, using the following equation: (VTHH/ITH) = kHOT(@40°C) × RNOM + R R = (VTHH/ITH) - kHOT(@40°C) × RNOM R = (2.5V/100µA) - 0.5758 × 6.8kΩ Finally, R = 5kΩ - 3.9kΩ = 1.1kΩ - 43 www.active-semi.com Copyright © 2009 Active-Semi, Inc. The ACT8828 was designed to accommodate most Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D This result shows that adding 1.1kΩ in series with the thermistor sets the net resistance from TH to G to be 0.5V at 40°C, satisfying VTHH at the correct temperature. Adding this resistance, however, also impacts the lower temperature limit as follows: VTHL/ITH = kCOLD(@TC) × RNOM + R kCOLD(@TC) = (VTHL/ITH) - R)/RNOM Finally, kCOLD(@TC) = (25kΩ - 1.1kΩ)/6.8kΩ = 3.51 Reviewing the characteristic curves, the lower threshold is found to move to -5°C, a change of only 1°C. As a result, the system satisfies the upper threshold of 40°C with an operating temperature range of -5°C to 40°C, vs. our design target of 0°C to 40°C. It is informative to highlight that due to the NTC behavior of the thermistor, the relative impact on the lower threshold is significantly smaller than the impact on the upper threshold. ACT8828 Rev 3, 24-Sep-09 TM CHARGER parallel with ITH. The desired resistance can be found using the following equation: (ITH + (VCHG_IN - VTHL)/R) × kCOLD(@0°C) × RNOM = VTHL Rearranging yields R = (VCHG_IN - VTHL)/(VTHL/(kCOLD(@0°C) × RNOM) - ITH) R = (5V - 2.5V)/(2.5V/(2.816 × 6.8kΩ) - 100µA) R = 82kΩ Adding 82kΩ in parallel with the current source increases the net current flowing into the thermistor, thus increasing the voltage at TH. Adding this resistance, however, also impacts the upper temperature limit: VTHH = (ITH + (VCHG_IN - VTHH)/R) × kHOT(@40°C) × RNOM Rearranging yields, kHOT(@TC) = VTHH/(RNOM × (ITH + (VCHG_IN - VTHH)/R)) kHOT(@TC) = 0.5V/(6.8kΩ × (100µA + (5V - 0.5V)/82kΩ)) = 0.4748 Reviewing the characteristic curves, the upper threshold is found to move to 45°C, a change of about 14°C. Adding the parallel resistance has allowed us to achieve our desired lower threshold of 0°C with an operating temperature range of 0°C to 45°C, vs. our design target of 0°C to 40°C. Fix VTHL Following the same example as above, the "unadjusted" results yield an operating temperature range of -6°C to 33°C vs. the design goal of 0°C to 40°C. In applications that favor VTHL over VTHH, however, one can control the voltage present at TH at low temperatures by connecting a resistor in Figure 8: Fix VTHH Configuration Figure 9: Fix VTHL Configuration ACT8828 100µA + – ACT8828 100µA + CHG_IN + VTHH TH R Li+ Battery Pack + – VTHH TH R Li+ Battery Pack + – NTC VTHL – + – NTC VTHL – Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 44 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D Thermal Regulation The ACT8828's ActivePath charger features an internal thermal regulation loop that reduces the charging current as necessary to ensure that the die temperature does not rise beyond the thermal regulation threshold of 110°C. This feature protects the against excessive junction temperature and makes the device more accommodating to aggressive thermal designs. Note, however, that attention to good thermal designs is required to achieve the fastest possible charge time by maximizing charge current. In order to account for the reduced charge current resulting from operation in thermal regulation mode, the charge timeout periods are extended proportionally to the reduction in charge current. Table 17: ACT8828 Rev 3, 24-Sep-09 TM CHARGER Charging Status Indication Table STATE Charging Discharging Charging Complete Input Floating Fault nSTAT ON OFF OFF OFF OFF Input Supply Detection The ACT8828's ActivePath charger is capable of withstanding voltages of up to 12V, protecting the system from fault conditions such as input voltage transients or application of an incorrect input supply. Although the ACT8828 can withstand a wide range of input voltages, valid input voltages for charging must be greater than the under-voltage lockout voltage (UVLO) and the over-voltage protection (OVP) thresholds, as described below. Under Voltage Lock Output (UVLO) Charging Safety Timers The ACT8828 features a safety timer that is programmable via an external resistor (RBTR) connected from BTR to GA. The timeout period is calculated as a function of this resistor by the following equation: tCHG = KBTR × RBTR, where KBTR = 0.24s/Ω. If the timeout period expires prior to charge termination, the charger is disabled and the nSTAT pin signal a fault condition. If the ACT8828 detects that the charger remains in precondition for longer than the precondition time out period (which determined as tCHG/3), the ACT8828 turns off the charger and generate a FAULT to ensure prevent charging a bad cell. Whenever the input voltage applied to CHG_IN falls below 3.8V (typ), an input under-voltage condition is detected and the charger is disabled. Once an input under-voltage condition is detected, the input must exceed the under-voltage threshold by at least 800mV for charging to resume. Over Voltage Protection (OVP) Charging Status Indication The ACT8828 provides one charge-status output, nSTAT which indicates charge status as defined in Table 17. nSTAT is open-drain output with internal 5mA current limits, which sinks current when asserted and are high-Z otherwise, and is capable of directly driving LED without the need of currentlimiting resistor or other external circuitry. To drive an LED, simply connect the LED between nSTAT pin and an appropriate supply (typically VSYS). For a logic level indication, simply connect a resistor from nSTAT to a appropriate voltage supply. If the charger detects that the voltage applied to CHG_IN exceeds 6.8V (typ), an over-voltage condition is detected and the charger is disabled. Once an input over-voltage condition is detected, the input must fall below the OVP threshold by at least 400mV for charging to resume. Reverse Leakage Current The ACT8828's ActivePath charger includes internal circuitry that eliminates the need for blocking diodes, reducing solution size and cost as well as dropout voltage relative to conventional battery chargers. When the voltage at CHG_IN falls below VBAT, the charger automatically reconfigures its power switch to minimize current drain from the battery Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 45 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath Figure 10: Typical Li+ Charge Profile and ACT8828 Charge States VSET RECHARGE ISET Current Voltage VPRECHARGE ACT8828 Rev 3, 24-Sep-09 TM CHARGER 12% ISET STATE A B C D E B A: PRECONDITION State B: FAST-CHARGE State C: TOP-OFF State D: SLEEP State E: DISCHARGE State Figure 11: Charger State Diagram ANY STATE BATTERY REMOVED OR VCHG_IN < VBAT + 120mV OR VCHG_IN < UVLO SUSPEND BATTERY REPLACED AND VCHG_IN > VBAT + 120mV AND VCHG_IN > UVLO T > TPRECONDITION AND VBAT < 2.85V TIMEOUT-FAULT PRECONDITION VBAT > 2.85V T > TNORMAL AND VBAT < VTERM FAST-CHARGE VBAT = VTERM TOP-OFF IBAT < ITERM IBAT > ITERM DELAY SLEEP VBAT < VTERM – 170mV Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 46 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D Charger State-Machine PRECONDITION State ACT8828 Rev 3, 24-Sep-09 TM CHARGER End of Charge State A new charging cycle begins with the PRECONDITION state, and operation continues in this state until VBAT exceeds the Precondition Threshold Voltage of 2.85V (typ). When operating in PRECONDITION state, the cell is charged at a reduced current, 12% of the programmed maximum fast-charge constant current, ISET. Once VBAT reaches the Precondition Threshold Voltage the state machine jumps to the NORMAL state. If VBAT does not reach the Precondition Threshold Voltage before the Precondition Timeout period tPRECONDITION expires, then a damaged cell is detected and the state machine jumps to the TIMEOUT-FAULT State. For the Precondition Timeout period, see the Charging Safety Timers section for more information. FAST CHARGE State In the End-of-Charge (EOC) state, the ACT8828 presents a high-impedance to the battery, allowing the cell to “relax” and minimizes battery leakage current. The ACT8828 continues to monitor the cell voltage, however, so that it can re-initiate charging cycles as necessary to ensure that the cell remains fully charged. SUSPEND State The ACT8828 features an user-selectable suspendcharge mode, which disables the charger but keeps other circuiting functional. The charger can be put into suspend mode by driving EN to logic low. Upon exiting the SUSPEND State, the charge timer is reset and the state machine jumps to PRECONDITION state. SLEEP State Normal state is made up of two operating modes, fast charge Constant-Current (CC) and ConstantVoltage (CV). In CC mode, the ACT8828 charges at the current programmed by RISET (see the Current Limits and Charge Current Programming section for more information). During a normal charge cycle fast-charge continues in CC mode until VBAT reaches the charge termination voltage (VTERM), at which point the ACT8828 charges in CV mode. Charging continues in CV mode until the charge current drops to 10% (ACIN = 1) or 5% (ACIN = 0) of the programmed maximum charge current, at which point the state machine jumps to the TOPOFF state. If VBAT does not proceed out of the NORMAL state before the Normal Timeout period (TNORMAL) expires, then a damaged cell is detected and the state machine jumps to the TIMEOUTFAULT State. See the Charging Safety Times section for more information. TOP-OFF State In SLEEP mode the ACT8828 presents a highimpedance to the battery, allowing the cell to “relax” and minimizes battery leakage current. The ACT8828 continues to monitor the cell voltage, however, so that it can re-initiate charging as necessary to ensure that the cell remains fully charged. Under normal operation, the state machine initiates a new charging cycle by jumping to the FAST-CHARGE state when VBAT drops below the Charge Termination Threshold. CHG_IN Bypass Capacitor Selection CHG_IN is the power input for the ACT8828 battery charger. The battery charger is automatically enabled whenever a valid voltage is present on CHG_IN. In most applications, CHG_IN is connected to either a wall adapter or USB port. Under normal operation, the input of the charger will often be “hot-plugged” directly to a powered USB or wall adapter cable, and supply voltage ringing and overshoot may appear at the CHG_IN pin. In most applications a high quality capacitor connected from CHG_IN to GA, placed as close as possible to the IC, is sufficient to absorb the energy. Wall-adapter powered applications provide flexibility in input capacitor selection, but the USB specification presents limitations to input capacitance selection. In order to meet both the USB 2.0 and USB OTG (On The Go) specifications while avoiding USB supply under-voltage conditions In the TOP-OFF state, the cell is charged in constant-voltage (CV) mode. Charge current decreases as charging continues. During a normal charging cycle charging proceeds until the charge current decreases below the End-Of-Charge (EOC) threshold, defined as 10% of ISET (ACIN = 1) or 5% of ISET (ACIN = 0) . When this happens, the state machine terminates the charge cycle and jumps to the SLEEP state. Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 47 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ActivePath FUNCTIONAL DESCRIPTION CONT’D resulting from the current limit slew rate (100mA/µS) limitations of the USB bus, the CHG_IN bypass capacitance value must to be between 4.7µF and 10µF for the ACT8828. Ceramic capacitors are often preferred for bypassing applications due to their small size and good surge current ratings, but care must be taken in applications that can encounter hot plug conditions as their very low ESR, in combination with the inductance of the cable, can create a highQ filter that induces excessive ringing at the CHG_IN pin. This ringing can couple to the output and be mistaken as loop instability, or the ringing may be large enough to damage the input itself. Although the CHG_IN pin is designed for maximum ACT8828 Rev 3, 24-Sep-09 TM CHARGER robustness and an absolute maximum voltage rating of 14V for transients, attention must be given to bypass techniques to ensure safe operation. As a result, design of the CHG_IN bypass must take care to “de-Q” the filter. This can be accomplished by connecting a 1Ω resistor in series with a ceramic capacitor (as shown in Figure 12), or by using a tantalum or electrolytic capacitor to utilize it’s higher ESR to dampen the ringing. For additional protection in extreme situations, Zener diodes with 12V clamp voltages may also be used. In any case, it is always critical to evaluate voltage transients at the ACT8828 CHG_IN pin with an oscilloscope to ensure safe operation. Figure 12: CHG_IN Bypass Options for USB or Wall Adaptor Supplies Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 48 - www.active-semi.com Copyright © 2009 Active-Semi, Inc. Active-Semi ACT8828 Rev 3, 24-Sep-09 PACKAGE OUTLINE AND DIMENSIONS PACKAGE OUTLINE TQFN55-40 PACKAGE OUTLINE AND DIMENSIONS D D/2 SYMBOL A E/2 DIMENSION IN MILLIMETERS MIN 0.700 DIMENSION IN INCHES MIN 0.028 MAX 0.800 MAX 0.031 A1 E 0.200 REF 0.000 0.150 4.900 4.900 3.450 3.450 0.050 0.250 5.100 5.100 3.750 3.750 0.008 REF 0.000 0.006 0.193 0.193 0.136 0.136 0.002 0.010 0.201 0.201 0.148 0.148 A2 b D E D2 A A1 D2 L b A2 E2 e L R 0.400 BSC 0.300 0.500 0.016 BSC 0.012 0.020 0.300 0.012 e E2 R Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact sales@active-semi.com or visit http://www.active-semi.com. For other inquiries, please send to: 2728 Orchard Parkway, San Jose, CA 95134-2012, USA Innovative PowerTM ActivePMUTM and ActivePathTM are trademarks of Active-Semi. I2CTM is a trademark of Philips Electronics. - 49 - www.active-semi.com Copyright © 2009 Active-Semi, Inc.