LTC4097EDDB

LTC4097 USB/Wall Adapter Standalone Li-Ion/Polymer Battery Charger FEATURES ■ ■ DESCRIPTION The LTC®4097 is a standalone linear battery charger that is capable of charging a single-cell Li-Ion or Li-Polymer battery from both wall adapter and USB inputs. The charger can detect power at the inputs and automatically select the appropriate power source for charging. No external sense resistor or blocking diode is required for charging due to the internal MOSFET architecture. Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The float voltage is fixed at 4.2V and the charge current is programmed with an external resistor. The LTC4097 terminates the charge cycle when the charge current drops below the user programmed termination threshold after the final float voltage is reached. The LTC4097 can be put into shutdown mode reducing the DCIN supply current to 20µA, the USBIN supply current to 10µA, and the battery drain current to less than 2µA even with power applied to both inputs. Other features include trickle charge, automatic recharge, undervoltage lockout, charge status output, an NTC thermistor input used to monitor battery temperature and VNTC power present output with 120mA drive capability. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Protected by U.S. Patents including 6522118. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Charges Single-Cell Li-Ion/Polymer Battery from Wall Adapter and USB Inputs Automatic Input Detection (Wall Adapter Input has Charging Priority) Charge Current Programmable up to 1.2A from Wall Adapter Input Programmable Charge Current Termination NTC Thermistor Input for Temperature Qualified Charging Independent DC, USB Charge Current Programming Preset Float Voltage with ±0.6% Accuracy Thermal Regulation Maximizes Charge Rate Without Risk of Overheating* Charge Status Output Automatic Recharge 20µA Charger Quiescent Current in Shutdown Available in a Thermally Enhanced, Low Profile (0.75mm) 12-Lead (3mm × 2mm) DFN Package APPLICATIONS ■ ■ ■ Cellular Telephones MP3 Players Portable Handheld Devices TYPICAL APPLICATION Dual Input Battery Charger for Single-Cell Li-Ion Battery LTC4097 WALL ADAPTER USB PORT 1µF 1µF 2k 1% BAT DCIN USBIN IUSB IDC 1.24k 1% VNTC HPWR NTC ITERM GND 2k 1% T 800mA (WALL) 100mA/500mA (USB) Complete Charge Cycle (1100mAh Battery) 1000 800 600 400 200 0 4.2 4.0 3.8 3.6 3.4 5.0 2.5 0 0 0.5 1.0 2.0 1.5 TIME (HR) 2.5 3.0 4097f + 4.2V SINGLE CELL Li-Ion BATTERY BATTERY CHARGE VOLTAGE (V) CURRENT (mA) CONSTANT VOLTAGE USBIN = 5V TA = 25°C RIDC = 1.24k RIUSB = 2k HPWR = 5V 4097 TA01 DCIN VOLTAGE (V) 4097 TA01b 1 LTC4097 ABSOLUTE MAXIMUM RATINGS (Note 1,7) PACKAGE/ORDER INFORMATION TOP VIEW DCIN 1 USBIN 2 VNTC 3 CHRG 4 SUSP 5 NTC 6 13 12 BAT 11 GND 10 IDC 9 IUSB 8 ITERM 7 HPWR VDCIN, VUSBIN t < 1ms and Duty Cycle < 1% .................. –0.3V to 7V Steady State............................................. –0.3V to 6V BAT, ⎯C⎯H⎯R⎯G, NTC, HPWR, SUSP ................... –0.3V to 6V IDC, IUSB, ITERM ............................–0.3V to VCC + 0.3V BAT Short-Circuit Duration............................Continuous VNTC Short-Circuit Duration .........................Continuous DCIN, BAT Pin Current (Note 6) .............................1.25A USBIN Pin Current (Note 6) .....................................1.1A IDC, IUSB, ITERM Pin Current ............................1.25mA Junction Temperature ........................................... 125°C Operating Temperature Range (Note 2) ... –40°C to 85°C Storage Temperature Range................... –65°C to 125°C DDB PACKAGE 12-LEAD (3mm × 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 60°C/W (Note 3) EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER LTC4097EDDB DDB PART MARKING LCRM Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS SYMBOL VDCIN VUSBIN IDCIN PARAMETER Adapter Supply Voltage USB Supply Voltage DCIN Supply Current The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 5V, VUSBIN = 5V, HPWR = 5V, NTC = 0V, RIDC = 1kΩ, RIUSB = 2kΩ, RITERM = 2kΩ unless otherwise noted. CONDITIONS ● ● MIN 4.25 4.25 TYP MAX 5.5 5.5 UNITS V V µA µA µA µA µA µA µA V V mA mA mA mA µA µA µA V V V Charge Mode (Note 4), RIDC = 10k Standby Mode; Charge Terminated Shutdown Mode (SUSP = 5V) Charge Mode (Note 5), RIUSB = 10k, VDCIN = 0V Standby Mode; Charge Terminated, VDCIN = 0V Shutdown (VDCIN = 0V, SUSP = 5V) VDCIN > VUSBIN IBAT = 1mA IBAT = 1mA, 0°C < TA < 85°C RIDC = 1.25k, Constant-Current Mode RIUSB = 2.1k, Constant-Current Mode RIUSB = 2.1k, Constant-Current Mode, HPWR = 0V RIDC = 10k or RIUSB = 10k Standby Mode, Charge Terminated Shutdown Mode (Charger Disabled) Sleep Mode (VDCIN = 0V, VUSBIN = 0V) Constant-Current Mode, RIDC = 1.25k Constant-Current Mode, RIUSB = 2k Constant-Current Mode, RIUSB = 2k, HPWR = 0 RITERM = 1k RITERM = 2k RITERM = 10k VBAT < VTRIKL; RIDC = 1k VBAT < VTRIKL; RIUSB = 2k ● ● ● ● 250 50 20 250 50 20 10 4.179 4.158 750 450 90 88 4.2 4.2 800 476 95 100 –5 –2 –5 1 1 0.2 88 42 6 85 42 100 50 9.5 100 50 800 100 40 800 100 40 20 4.221 4.242 850 500 100 112 –8 –4 –8 IUSBIN USBIN Supply Current VFLOAT IBAT Regulated Output (Float) Voltage BAT Pin Current VIDC VIUSB ITERMINATE IDC Pin Regulated Voltage IUSB Pin Regulated Voltage Charge Current Termination Threshold Trickle Charge Current 112 58 13 115 58 mA mA mA mA mA 4097f ITRIKL 2 LTC4097 ELECTRICAL CHARACTERISTICS SYMBOL VTRIKL VUVDC VUVUSB VASD-DC VASD-USB VSUSP, VHPWR RSUSP RHPWR V⎯C⎯H⎯R⎯G ΔVRECHRG tRECHRG tITERM RON-DC RON-USB TLIM IVNTC VVNTC INTC VNTC-COLD VNTC-HOT VNTC-DIS PARAMETER The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 5V, VUSBIN = 5V, HPWR = 5V, NTC = 0V, RIDC = 1kΩ, RIUSB = 2kΩ, RITERM = 2kΩ unless otherwise noted. CONDITIONS ● MIN 2.8 4 3.8 5 5 TYP 2.9 135 4.22 200 4 200 30 100 30 150 MAX 3 4.4 4.2 55 55 0.5 UNITS V mV V mV V mV mV mV mV mV V V MΩ MΩ Trickle Charge Threshold Voltage VBAT Rising Hysteresis DCIN Undervoltage Lockout Voltage USBIN Undervoltage Lockout Voltage VDCIN – VBAT Lockout Threshold Voltage From Low to High Hysteresis From Low to High Hysteresis VDCIN from High to Low, VBAT = 4.3V VDCIN from Low to High, VBAT = 4.3V VUSBIN – VBAT Lockout Threshold VUSBIN from High to Low, VBAT = 4.3V Voltage VUSBIN from Low to High, VBAT = 4.3V VIL, Logic Low Voltage VIH, Logic High Voltage SUSP Pulldown Resistance HPWR Pulldown Resistance ⎯C⎯H⎯R⎯G Output Low Voltage Recharge Battery Threshold Voltage I⎯C⎯H⎯R⎯G = 5mA VFLOAT – VRECHRG ● ● ● 1.2 3.4 3.4 62 70 100 1.6 3 420 470 115 VVNTC = 4.55V DCIN Powered VVNTC = 4.8V USBIN Powered IVNTC = 250µA VNTC = 1V Rising Threshold Hysteresis 4.25 0 0.765 • VVNTC 0.016 • VVNTC 0.349 • VVNTC 0.016 • VVNTC 0.017 • VVNTC 0.01 • VVNTC 30 30 5.5 ±1 150 130 mV mV ms ms mΩ mΩ °C mA mA V µA V V V V V V Recharge Comparator Filter Time VBAT from High to Low Termination Comparator Filter Time IBAT Drops Below Termination Threshold Power FET “ON” Resistance (Between DCIN and BAT) Power FET “ON” Resistance (Between USBIN and BAT) Junction Temperature in Constant-Temperature Mode VNTC Pin Current VNTC Bias Voltage NTC Input Leakage Current Cold Temperature Fault Threshold Voltage Hot Temperature Fault Threshold Falling Threshold Voltage Hysteresis NTC Disable Threshold Voltage NTC Input Voltage to GND (Falling) Hysteresis Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC4097 is guaranteed to meet the performance specifications from 0°C to 85°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Failure to correctly solder the Exposed Pad of the package to the PC board will result in a thermal resistance much higher than 60°C/W. See Thermal Considerations. Note 4: Supply current includes IDC and ITERM pin current (approximately 100µA each) but does not include any current delivered to the battery through the BAT pin. Note 5: Supply current includes IUSB and ITERM pin current (approximately 100µA each) but does not include any current delivered to the battery through the BAT pin. Note 6: Guaranteed by long term current density limitations. Note 7: VCC is greater of DCIN or USBIN 4097f 3 LTC4097 TYPICAL PERFORMANCE CHARACTERISTICS Battery Regulated Output (Float) Voltage vs Charge Current 4.26 4.24 4.22 VBAT (V) VBAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 0 200 400 600 800 1000 CHARGE CURRENT (mA) 1200 VDCIN = 5V RIDC = 1k 4.26 4.24 4.22 VBAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 0 100 300 400 500 CHARGE CURRENT (mA) 200 600 4097 G02 NTC = 0V, HPWR = 5V, TA = 25°C, unless otherwise noted. Battery Regulated Output (Float) Voltage vs Temperature 4.215 4.210 4.205 4.200 4.195 4.190 4.185 4.180 4.175 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G03 Battery Regulated Output (Float) Voltage vs Charge Current VUSBIN = 5V RIUSB = 2k VDCIN = 5V RIDC = 1k VUSBIN = 5V RIUSB = 2k 4097 G01 Battery Regulated Output (Float) Voltage vs DCIN Voltage 4.26 4.24 4.22 VBAT (V) VBAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 4.25 4.50 4.75 5.00 VDCIN (V) 5.25 5.50 4097 G04 Battery Regulated Output (Float) Voltage vs USBIN Voltage 4.26 4.24 4.22 IBAT (mA) 4.20 4.18 4.16 4.14 4.12 4.10 4.25 4.50 4.75 5.00 VUSBIN (V) 5.25 5.50 4097 G05 Charge Current vs IDC Pin Voltage 1200 1000 800 600 400 200 0 0 0.2 0.4 0.6 0.8 VIDC (V) 1.0 1.2 4097 G06 IBAT = 10mA RIDC = 1k IBAT = 10mA RIUSB = 2k VDCIN = 5V RIDC = 1k Charge Current vs IUSB Pin Voltage 600 500 400 IBAT (mA) 300 200 100 0 0 0.2 0.4 0.6 VIUSB (V) 4097 G07 IDC Pin Voltage vs Temperature (Constant-Current Mode) 1.006 1.004 1.002 1.000 0.998 0.996 0.994 –50 VIUSB (V) VIDC (V) VDCIN = 5V RIDC = 10k 1.006 1.004 1.002 1.000 0.998 0.996 IUSB Pin Voltage vs Temperature (Constant-Current Mode) VUSBIN = 5V RIUSB = 10k VUSBIN = 5V RIUSB = 2k 0.8 1.0 1.2 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G08 0.994 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G09 4097f 4 LTC4097 TYPICAL PERFORMANCE CHARACTERISTICS IDC Pin Voltage vs VDCIN (Constant-Current Mode) 1.006 1.004 1.002 1.000 0.998 0.996 0.994 4.25 VIUSB (V) VIDC (V) VBAT = 3.7V RIDC = 10k 1.006 1.004 ∆VRECHRG (mV) 1.002 1.000 0.998 0.996 0.994 4.25 NTC = 0V, HPWR = 5V, TA = 25°C, unless otherwise noted. Recharge Threshold Voltage vs Temperature 120 115 110 105 100 95 90 85 VDCIN = VUSBIN = 5V IUSB Pin Voltage vs VUSBIN (Constant-Current Mode) VBAT = 3.7V RIUSB = 10k 4.50 4.75 5.00 VDCIN (V) 5.25 5.50 4097 G10 4.50 4.75 5.00 VUSBIN (V) 5.25 5.50 4097 G11 80 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G12 Charge Current vs Battery Voltage 1200 1150 1100 IBAT (mA) IBAT (mA) 1050 1000 950 900 850 800 3.0 3.2 3.4 3.6 VBAT (V) 3.8 4.0 4097 G13 Charge Current vs Battery Voltage 600 575 550 IBAT (mA) VUSBIN = 5V RIUSB = 2k 1200 Charge Current vs Ambient Temperature with Thermal Regulation RIDC = 1k 1000 800 600 R IUSB = 2k 400 VDCIN = 5V 200 VUSBIN = 5V VBAT = 3.7V θJA = 60°C/W 0 –50 –25 0 25 50 75 TEMPERATURE (°C) THERMAL REGULATION VDCIN = 5V RIDC = 1k THERMAL REGULATION 525 500 475 450 425 400 3.0 3.2 3.4 3.6 VBAT (V) 3.8 4.0 4097 G14 100 125 4097 G15 Charge Current vs Supply Voltage 104 VBAT = 3.7V 1200 1000 102 IBAT (mA) IBAT (mA) RIDC = 10k 100 RIUSB = 10k 800 Charge Current vs Battery Voltage 600 THERMAL REGULATION 500 400 IBAT (mA) 300 200 VDCIN = 5V RIDC = 1k θJA = 60°C/W 2.5 3.0 3.5 VBAT (V) 4.0 4.5 4097 G17 Charge Current vs Battery Voltage 600 400 98 200 96 4.25 0 2.0 100 0 2.0 VUSBIN = 5V RIUSB = 2k θJA = 60°C/W 2.5 3.0 3.5 VBAT (V) 4.0 4.5 4097 G18 4.50 5.00 VDCIN, VUSBIN (V) 4.75 5.25 5.50 4097 G16 4097f 5 LTC4097 TYPICAL PERFORMANCE CHARACTERISTICS DCIN Power FET On-Resistance vs Temperature 550 VDCIN = 4V IBAT = 200mA 550 NTC = 0V, HPWR = 5V, TA = 25°C, unless otherwise noted. VNTC-DCIN and VNTC-USBIN Power FET On-Resistance vs Temperature 20 VDCIN = 5V IVNTC = 30mA 15 RVNTC (Ω) USBIN Power FET On-Resistance vs Temperature VUSBIN = 4V IBAT = 200mA 500 RUSBON (mΩ) RDCON (mΩ) 500 450 450 10 400 400 350 350 5 VUSBIN = 5V IVNTC = 30mA 300 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G19 300 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G20 0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G21 VVNTC vs IVNTC 6 5 4 ICHRG (mA) VVNTC (V) 3 2 1 0 0 25 50 75 100 IVNTC (mA) 125 150 4097 G22 ⎯C⎯H⎯R⎯G Pin I-V Curve 120 100 80 VDCIN = VUSBIN = 5V VBAT = 4V 100 ⎯C⎯H⎯R⎯G Pin Output Low Voltage vs Temperature ICHRG = 5mA VDCIN = VUSBIN = 5.5V VUSBIN = 5V 80 VCHRG (mV) 60 VDCIN = VUSBIN = 4.25V 40 VDCIN = 5V 60 40 20 0 0 1 2 3 VCHRG (V) 4097 G23 20 4 5 6 0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G24 SUSP Pin Threshold Voltage (On-to-Off) vs Temperature 1000 950 900 850 800 750 700 –50 VDCIN = VUSBIN = 5V 1000 950 HPWR Pin Threshold Voltage (On-to-Off) vs Temperature VDCIN = 0V VUSBIN = 5V 4.5 SUSP Pin Pulldown Resistance vs Temperature 4.0 VHPWR (mV) RSUSP (MΩ) VSUSP (mV) 900 850 800 3.0 750 700 –50 2.5 –50 3.5 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G25 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G26 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G27 4097f 6 LTC4097 TYPICAL PERFORMANCE CHARACTERISTICS HPWR Pin Pulldown Resistance vs Temperature 4.5 60 50 4.0 RHPWR (MΩ) 40 3.5 IDCIN (µA) 30 VDCIN = 5.5V 20 3.0 10 2.5 –50 0 –50 VDCIN = 4.25V NTC = 0V, HPWR = 5V, TA = 25°C, unless otherwise noted. Shutdown Supply Current vs Temperature and VDCIN SUSP = VDCIN VUSBIN = VDCIN –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G28 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G29 Shutdown Supply Current vs Temperature and VUSBIN 60 50 40 IUSBIN (µA) VUV (V) 30 VUSBIN = 5.5V 20 10 0 –50 VUSBIN = 4.25V SUSP = VUSBIN VDCIN = 0V 4.10 4.05 Undervoltage Lockout Voltage (Falling) vs Temperature DCIN UVLO 4.00 3.95 3.90 3.85 3.80 3.75 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G30 USBIN UVLO 3.70 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4097 G31 4097f 7 LTC4097 PIN FUNCTIONS DCIN (Pin 1): Wall Adapter Input Supply Pin. Provides power to the battery charger. The maximum supply current is 1.2A. This pin should be bypassed with a 1µF capacitor. USBIN (Pin 2): USB Input Supply Pin. Provides power to the battery charger. The maximum supply current is 1A. This pin should be bypassed with a 1µF capacitor. VNTC (Pin 3): Output Bias Voltage for NTC. A resistor from this pin to the NTC pin sets up the bias for an NTC thermistor. When the DCIN or USBIN pin voltage is sufficient to begin charging (i.e. when the DCIN or USBIN supply is greater than the undervoltage lockout thresholds and at least 100mV or 150mV, respectively, above the battery terminal), the VNTC pin is connected to the appropriate input through an internal P-channel MOSFET. If sufficient voltage to charge is not present on DCIN or USBIN the VNTC pin is high impedance. This output can source up to 120mA. ⎯⎯⎯⎯ CHRG (Pin 4): Open-Drain Charge Status Output. When ⎯⎯⎯⎯ the LTC4097 is charging, the CHRG pin is pulled low by an internal N-channel MOSFET. When the charge cycle is com⎯⎯⎯⎯ pleted, CHRG becomes high impedance. This output can sink up to 10mA, making it suitable for driving a LED. SUSP (Pin 5): Charge Enable Input. A logic low on this pin enables the charger. If left floating, an internal 3.4MΩ pull-down resistor defaults the LTC4097 to charge mode. Pull this pin high for shutdown. NTC (Pin 6): Input to the NTC (Negative Temperature Coefficient) Thermistor Temperature Monitoring Circuit. For normal operation, connect a thermistor from the NTC pin to ground and a resistor of equal value from the NTC pin to VNTC. When the voltage at this pin drops below 0.349 • VNTC at hot temperatures or rises above 0.765 • VNTC at cold, charging is suspended and the ⎯C⎯H⎯R⎯G pin output will keep the state in which it was before the event (low-Z or high-Z). Pulling this pin below 0.017 • VNTC disables the NTC feature. There is approximately 2°C of temperature hysteresis associated with each of the input comparator’s thresholds. HPWR (Pin 7): HPWR Enable Input. Used to control the amount of current drawn from the USB port. A logic high on the HPWR pin sets the charge current to 100% of the current programmed by the IUSB pin. A logic low on the HPWR pin sets the charge current to 20% of the current programmed by the IUSB pin. An internal 3.4MΩ pull-down resistor defaults the HPWR pin to its low current state. ITERM (Pin 8): Charge Termination Current Threshold Program. The termination current threshold, ITERMINATE, is set by connecting a resistor, RITERM, to ground. ITERMINATE is set by the following formula: ITERMINATE = 100V RITERM When the battery current, IBAT, falls below the termination threshold, charging stops and the ⎯C⎯H⎯R⎯G output becomes high impedance. 4097f 8 LTC4097 PIN FUNCTIONS IUSB (Pin 9): Charge Current Program for USB Power. The charge current is set by connecting a resistor, RIUSB, to ground. When charging in constant current mode, this pin servos to 1V. The voltage on this pin can be used to measure the battery current delivered from the USBIN input using the following formula: IBAT = VIUSB • 1000 RIUSB to measure the battery current delivered from the DCIN input using the following formula: IBAT = VIDC •1000 RIDC GND (Pin 11): Ground. BAT (Pin 12): Charger Output. This pin provides charge current to the battery and regulates the final float voltage to 4.2V. Exposed Pad (Pin 13): Ground. The exposed backside of the package is ground and must be soldered to the PC board ground for electrical connection and maximum heat transfer. IDC (Pin 10): Charge Current Program for Wall Adapter Power. The charge current is set by connecting a resistor, RIDC, to ground. When charging in constant current mode, this pin servos to 1V. The voltage on this pin can be used 4097f 9 LTC4097 BLOCK DIAGRAM DCIN 1 VNTC 3 R1 RNOM CC/CV REGULATOR CC/CV REGULATOR BAT 12 USBIN 2 – R2 TOO COLD + 4.2V + – DCIN UVLO TOO HOT DCON USBON + – USBIN UVLO 4V NTC 6 RNTC R3 BAT – R4 SUSPEND CHRG 4 10mA MAX LOGIC RECHRG TRICKLE TERM TRICKLE CHARGE SUSP 5 RSUSP TERMINATION 10 – + + + – – + NTC_EN + – BAT 7 HPWR + RECHARGE 4.1V RHPWR – BAT DC_ENABLE USB_ENABLE CHARGER CONTROL 2.9V THERMAL REGULATION AND SHUTDOWN 100mV IBAT/1000 IBAT/1000 IBAT/1000 + – – TDIE 115°C 150°C + – ITERM 8 RITERM IDC 10 RIDC 9 IUSB GND 11, 13 4097 BD RIUSB 4097f LTC4097 OPERATION The LTC4097 is designed to efficiently manage charging a single-cell lithium-ion battery from two separate power sources: a wall adapter and USB power bus. Using the constant-current/constant-voltage algorithm, the charger can deliver up to 1.2A of charge current from the wall adapter supply or up to 1A of charge current from the USB supply with a final float voltage accuracy of ±0.6%. The LTC4097 has two internal P-channel power MOSFETs, thermal regulation and shut down circuitry. No blocking diodes or external sense resistors are required. Power Source Selection The LTC4097 can charge a battery from either the wall adapter input or the USB port input. The LTC4097 automatically senses the presence of voltage at each input. If both power sources are present, the LTC4097 defaults to the wall adapter source provided sufficient power is present at the DCIN input. “Sufficient power” is defined as: • Supply voltage is greater than the UVLO threshold. • Supply voltage is greater than the battery voltage by 30mV (100mV or 150mV rising, 30mV falling). The VNTC output pin indicates that sufficient input voltage is available. Table 1 describes the behavior of the power source selection. Table 1. Power Source Selection VUSBIN > 4V and VUSBIN > BAT + 30mV VDCIN > 4.2V and VDCIN > BAT + 30mV VDCIN < 4.2V or VDCIN < BAT + 30mV VUSBIN < 4V or VUSBIN < BAT + 30mV Programming and Monitoring Charge Current The charge current delivered to the battery from the wall adapter supply is programmed using a single resistor from the IDC pin to ground. RIDC = 1000 V ICHRG(DC) , ICHRG(DC) = 1000 V RIDC Similarly, the charge current from the USB supply is programmed using a single resistor from the IUSB pin to ground. Setting HPWR pin to its high state will select 100% of the programmed charge current, while setting HPWR to its low state will select 20% of the programmed charge current. RIUSB = 1000 V ICHRG(USB) (HPWR = HIGH) ICHRG(USB) = ICHRG(USB) = 1000 V (HPWR = HIGH) RIUSB 200 V (HPWR = LOW) RIUSB Charge current out of the BAT pin can be determined at any time by monitoring the IDC or IUSB pin voltage and applying the following equations: IBAT = IBAT = VIDC • 1000, (ch arg ing from wall adapter ) RIDC VIUSB • 1000, RIUSB Charger powered from Charger powered from wall adapter source; wall adapter source USBIN current < 25µA Charger powered from No charging USB source (ch arg ing from USB sup ply, HPWR = HIGH) IBAT = VIUSB • 200, RIUSB (ch arg ing from USB sup ply, HPWR = LOW) 4097f 11 LTC4097 OPERATION Programming Charge Termination The charge cycle terminates when the charge current falls below the programmed termination threshold during constant-voltage mode. This threshold is set by connecting an external resistor, RITERM, from the ITERM pin to ground. The charge termination current threshold (ITERMINATE) is set by the following equation: RITERM = 100V ITERMINATE , ITERMINATE = 100V RITERM programmed to charge at 800mA from the wall adapter input and 500mA from the USB input, the charge current during trickle charge mode would be 80mA and 50mA, respectively. Automatic Recharge In standby mode, the charger sits idle and monitors the battery voltage using a comparator with a 1.6ms filter time (tRECHRG). A charge cycle automatically restarts when the battery voltage falls below 4.1V (which corresponds to approximately 80%-90% battery capacity). This ensures that the battery is kept at, or near, a fully charged condition and eliminates the need for periodic charge cycle initiations. If the battery is removed from the charger, a sawtooth waveform appears at the battery output. This is caused by the repeated cycling between termination and recharge events. This cycling results in pulsing at the ⎯C⎯H⎯R⎯G output; an LED connected to this pin will exhibit a blinking pattern, indicating to the user that a battery is not present. The frequency of the sawtooth is dependent on the amount of output capacitance. Status Indicators ⎯⎯⎯⎯ The charge status output (CHRG) has two states: pull-down and high impedance. The pull-down state indicates that the LTC4097 is in a charge cycle. Once the charge cycle has terminated or the LTC4097 is disabled, the pin state becomes high impedance. The pull-down state is capable of sinking up to 10mA. The power present output (VNTC) has two states: DCIN/ USBIN voltages and high impedance. The high impedance state indicates that sufficient voltage is not present at either DCIN or USBIN, therefore no charging will occur. The VNTC output is capable of sourcing up to 120mA steady state and includes short circuit protection. The termination condition is detected by using an internal filtered comparator to monitor the ITERM pin. When the ITERM pin voltage drops below 100mV* for longer than tTERMINATE (typically 3ms), the charge cycle terminates, charge current latches off and the LTC4097 enters standby mode. When charging, transient loads on the BAT pin can cause the ITERM pin to fall below 100mV for short periods of time before the DC charge current has dropped below the programmed termination current. The 3ms filter time (tTERMINATE) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termination. Once the average charge current drops below the programmed termination threshold, the LTC4097 terminates the charge cycle and ceases to provide any current out of the BAT pin. In this state, any load on the BAT pin must be supplied by the battery. Low-Battery Charge Conditioning (Trickle Charge) This feature ensures that deeply discharged batteries are gradually charged before applying full charge current. If the BAT pin voltage is below 2.9V, the LTC4097 supplies 1/10th of the full charge current to the battery until the BAT pin rises above 2.9V. For example, if the charger is *Any external sources that hold the ITERM pin above 100mV will prevent the LTC4097 from terminating a charge cycle. 4097f 12 LTC4097 OPERATION Manual Shutdown The SUSP pin has a 3.4MΩ pulldown resistor to GND. A logic low enables the charger and a logic high disables it (the pulldown defaults the charger to the charging state). The DCIN input draws 20µA when the charger is in shutdown. The USBIN input draws 20µA during shutdown if no power is applied to DCIN, but draws only 10µA when VDCIN > VUSBIN. NTC Thermistor The battery temperature is measured by placing a negative temperature coefficient (NTC) thermistor close to the battery pack. The NTC circuitry is shown in the Block Diagram of Figure 4. To use this feature, connect the NTC thermistor, RNTC, between the NTC pin and ground and a bias resistor, RNOM, from VNTC to NTC. RNOM should be a 1% resistor with a value equal to the value of the chosen NTC thermistor at 25°C (R25). The LTC4097 will pause charging when the resistance of the 100k NTC thermistor drops to 0.54 times the value of R25 or approximately 54k (for a Vishay “Curve 1” thermistor, this corresponds to approximately 40°C). As the temperature drops, the resistance of the NTC thermistor rises. The LTC4097 is also designed to pause charging when the value of the NTC thermistor increases to 3.25 times the value of R25. For a Vishay “Curve 1” thermistor this resistance, 325k, corresponds to approximately 0°C. The hot and cold comparators each have approximately 3°C of hysteresis to prevent oscillation about the trip point. Grounding the NTC pin disables all NTC functionality. Thermal Limiting An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 115°C. This feature protects the LTC4097 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the device. The charge current can be set according to typical (not worst case) ambient temperature with the assurance that the charger will automatically reduce the current in worst case conditions. A safety thermal shut down circuit will turn off the charger if the die temperature rises above a value of approximately 150°C. DFN power considerations are discussed further in the Applications Information section. 4097f 13 LTC4097 OPERATION STARTUP DCIN POWER APPLIED POWER SELECTION DCIN POWER REMOVED USBIN POWER REMOVED OR DCIN POWER APPLIED ONLY USB POWER APPLIED BAT < 2.9V TRICKLE CHARGE MODE 1/10th FULL CURRENT CHRG STATE: PULLDOWN BAT > 2.9V TRICKLE CHARGE MODE 1/10th FULL CURRENT CHRG STATE: PULLDOWN BAT > 2.9V CHARGE MODE FULL CURRENT⇒HPWR = HIGH 1/5 FULL CURRENT⇒HPWR = LOW CHRG STATE: PULLDOWN BAT < 2.9V 2.9V < BAT CHARGE MODE FULL CURRENT CHRG STATE: PULLDOWN 2.9V < BAT IBAT < ITERMINATE IN VOLTAGE MODE STANDBY MODE BAT < 4.1V NO CHARGE CURRENT CHRG STATE: Hi-Z IBAT < ITERMINATE IN VOLTAGE MODE STANDBY MODE NO CHARGE CURRENT CHRG STATE: Hi-Z BAT < 4.1V SUSP DRIVEN LOW SHUTDOWN MODE IDCIN DROPS TO 20µA CHRG STATE: Hi-Z SUSP DRIVEN HIGH SUSP DRIVEN HIGH SHUTDOWN MODE IUSBIN DROPS TO 20µA SUSP DRIVEN LOW DCIN POWER REMOVED USBIN POWER REMOVED OR DCIN POWER APPLIED CHRG STATE: Hi-Z 4097 F01 Figure 1. LTC4097 State Diagram of a Charge Cycle 4097f 14 LTC4097 APPLICATIONS INFORMATION Using a Single Charge Current Program Resistor In applications where the programmed wall adapter charge current and USB charge current are the same, a single program resistor can be used to set both charge currents. Figure 2 shows a charger circuit that uses one charge current program resistor. In this circuit, one resistor programs the same charge current for each input supply. ICHRG(DC) = ICHRG(USB) = 1000 V RSET Power Dissipation When designing the battery charger circuit, it is not necessary to design for worst-case power dissipation scenarios because the LTC4097 automatically reduces the charge current during high power conditions. The conditions that cause the LTC4097 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the IC. Most of the power dissipation is generated from the internal MOSFET pass device. Thus, the power dissipation is calculated to be: PD = (VCC – VBAT) • IBAT PD is the power dissipated, VCC is the input supply voltage (either DCIN or USBIN), VBAT is the battery voltage and IBAT is the charge current. The approximate ambient temperature at which the thermal feedback begins to protect the IC is: TA = 115°C – PD • θJA TA = 115°C – (VCC – VBAT) • IBAT • θJA Example: An LTC4097 operating from a 5V USB adapter (on the USBIN input) is programmed to supply 500mA full-scale current to a discharged Li-Ion battery with a voltage of 3.3V. Assuming θJA is 60°C/W (see Thermal Considerations), the ambient temperature at which the LTC4097 will begin to reduce the charge current is approximately: TA = 115°C – (5V – 3.3V) • (500mA) • 60°C/W TA = 115°C – 0.85W • 60°C/W = 115°C – 51°C TA = 64°C WALL ADAPTER USB PORT LTC4097 DCIN USBIN 1µF 1µF BAT VNTC HPWR NTC IUSB RIUSB 2k 1% RIDC 1.24k 1% IDC CHRG ITERM GND RITERM 2k 1% RNTC 100k RNTCBIAS 100k 1k 800mA (WALL) 100mA/500mA (USB) The LTC4097 can also program the wall adapter charge current and USB charge current independently using two program resistors, RIDC and RIUSB. Figure 3 shows a charger circuit that sets the wall adapter charge current to 800mA and the USB charge current to 500mA. Stability Considerations The constant-voltage mode feedback loop is stable without any compensation provided a battery is connected to the charger output. However, a 4.7µF capacitor with a 1Ω series resistor is recommended at the BAT pin to keep the ripple voltage low when the battery is disconnected. When the charger is in constant-current mode, the charge current program pin (IDC or IUSB) is in the feedback loop, not the battery. The constant-current mode stability is affected by the impedance at the charge current program pin. With no additional capacitance on this pin, the charger is stable with program resistor values as high as 20KΩ (ICHRG = 50mA); however, additional capacitance on these nodes reduces the maximum allowed program resistor. 100mA (USB, HPWR = LOW) 500mA WALL ADAPTER USB PORT 1µF 1µF RISET 2k 1% LTC4097 DCIN USBIN IUSB IDC ITERM GND BAT HPWR + RITERM 2k 1% 4.2V 1-CELL Li-Ion BATTERY + 4.2V 1-CELL Li-Ion BATTERY 4097 F02 Figure 2. Dual Input Charger Circuit. The Wall Adapter Charge Current and USB Charge Current are Both Programmed to be 500mA 4097 F03 Figure 3. Full Featured Dual Input Charger Circuit 4097f 15 LTC4097 APPLICATIONS INFORMATION The LTC4097 can be used above 64°C ambient, but the charge current will be reduced from 500mA. The approximate current at a given ambient temperature can be approximated by: IBAT = 115°C – TA ( VIN – VBAT ) • θ JA the upper and lower temperatures are pre-programmed to approximately 40°C and 0°C, respectively (assuming a Vishay “Curve 1” thermistor). The upper and lower temperature thresholds can be adjusted by either a modification of the bias resistor value or by adding a second adjustment resistor to the circuit. If only the bias resistor is adjusted, then either the upper or the lower threshold can be modified but not both. The other trip point will be determined by the characteristics of the thermistor. Using the bias resistor in addition to an adjustment resistor, both the upper and the lower temperature trip points can be independently programmed with the constraint that the difference between the upper and lower temperature thresholds cannot decrease. Examples of each technique are given below. NTC thermistors have temperature characteristics which are indicated on resistance-temperature conversion tables. The Vishay-Dale thermistor NTHS0603N011-N1003F, used in the following examples, has a nominal value of 100k and follows the Vishay “Curve 1” resistance-temperature characteristic. In the explanation below, the following notation is used. R25 = Value of the Thermistor at 25°C RNTC|COLD = Value of thermistor at the cold trip point RNTC|HOT = Value of the thermistor at the hot trip point rCOLD = Ratio of RNTC|COLD to R25 rHOT= Ratio of RNTC|HOT to R25 RNOM = Primary thermistor bias resistor (see Figure 4) R1 = Optional temperature range adjustment resistor (see Figure 5) The trip points for the LTC4097’s temperature qualification are internally programmed at 0.349 • VNTC for the hot threshold and 0.765 • VNTC for the cold threshold. Therefore, the hot trip point is set when: RNTC|HOT RNOM + RNTC|HOT • VNTC = 0.349 • VNTC 4097f Using the previous example with an ambient temperature of 75°C, the charge current will be reduced to approximately: IBAT = 115°C – 75°C 40°C = (5V – 3.3V) • 60°C / W 102°C / A IBAT = 392mA It is important to remember that LTC4097 applications do not need to be designed for worst-case thermal conditions, since the IC will automatically reduce power dissipation when the junction temperature reaches approximately 115°C. Moreover a thermal shut down protection circuit around 150°C safely prevents any damage by forcing the LTC4097 into shut down mode. Thermal Considerations In order to deliver maximum charge current under all conditions, it is critical that the exposed metal pad on the backside of the LTC4097 package is properly soldered to the PC board ground. When correctly soldered to a 2500mm2 double sided 1oz copper board, the LTC4097 has a thermal resistance of approximately 60°C/W. Failure to make thermal contact between the exposed pad on the backside of the package and the copper board will result in thermal resistances far greater than 60°C/W. As an example, a correctly soldered LTC4097 can deliver over 500mA to a battery from a 5V supply at room temperature. Without a good backside thermal connection, this number would drop to much less than 300mA. Alternate NTC Thermistors and Biasing The LTC4097 provides temperature qualified charging if a grounded thermistor and a bias resistor are connected to NTC. By using a bias resistor whose value is equal to the room temperature resistance of the thermistor (R25) 16 LTC4097 APPLICATIONS INFORMATION VNTC 3 RNOM 100k NTC 6 0.765 • VNTC NTC BLOCK VNTC 3 RNOM 105k TOO_COLD NTC 6 0.765 • VNTC NTC BLOCK – + – TOO_COLD + RNTC 100k 0.349 • VNTC – TOO_HOT R1 12.7k 0.349 • VNTC RNTC 100k – TOO_HOT + + + NTC_ENABLE 0.1V + NTC_ENABLE 0.1V – 4097 F04 – 4097 F05 Figure 4. Typical NTC Thermistor Circuit Figure 5. NTC Thermistor Circuit with Additional Bias Resistor and the cold trip point is set when: RNTC|COLD RNOM + RNTC|COLD • VNTC = 0.765 • VNTC Solving these equations for RNTC|COLD and RNTC|HOT results in the following: RNTC|COLD = 0.536 • RNOM and RNTC|COLD = 3.25 • RNOM By setting RNOM equal to R25, the above equations result in rHOT = 0.536 and rCOLD = 3.25. Referencing these ratios to the Vishay Resistance-Temperature Curve 1 chart gives a hot trip point of about 40°C and a cold trip point of about 0°C. The difference between the hot and cold trip points is approximately 40°C. By using a bias resistor, RNOM, different in value from R25, the hot and cold trip points can be moved in either direction. The temperature span will change somewhat due to the non-linear behavior of the thermistor. The following equations can be used to easily calculate a new value for the bias resistor: RNOM = RNOM = rHOT • R25 0.536 rCOLD • R25 3.25 where rHOT and rCOLD are the resistance ratios at the desired hot and cold trip points. Note that these equations are linked. Therefore, only one of the two trip points can be chosen, the other is determined by the default ratios designed in the IC. Consider an example where a 60°C hot trip point is desired. From the Vishay Curve 1 R-T characteristics, rHOT is 0.2488 at 60°C. Using the above equation, RNOM should be set to 46.4k. With this value of RNOM, the cold trip point is about 16°C. Notice that the span is now 44°C rather than the previous 40°C. This is due to the decrease in “temperature gain” of the thermistor as absolute temperature increases. The upper and lower temperature trip points can be independently programmed by using an additional bias resistor as shown in Figure 5. The following formulas can be used to compute the values of RNOM and R1: RNOM = rCOLD – rHOT • R25 2.714 R1 = 0.536 • RNOM – rHOT • R25 For example, to set the trip points to 0°C and 45°C with a Vishay Curve 1 thermistor choose RNOM = 3.266 – 0.4368 • 100k = 104.2k 2.714 4097f 17 LTC4097 APPLICATIONS INFORMATION the nearest 1% value is 105k. R1 = 0.536 • 105k – 0.4368 • 100k = 12.6k the nearest 1% value is 12.7k. The final solution is shown in Figure 5 and results in an upper trip point of 45°C and a lower trip point of 0°C. Protecting the USB Pin and Wall Adapter Input from Overvoltage Transients Caution must be exercised when using ceramic capacitors to bypass the USBIN or the wall adapter inputs. High voltage transients can be generated when the USB or wall adapter is hot plugged. When power is supplied via the USB bus or wall adapter, the cable inductance along with the self resonant and high Q characteristics of ceramic capacitors can cause substantial ringing which could exceed the maximum voltage ratings and damage the LTC4097. Refer to Linear Technology Application Note 88, entitled “Ceramic Input Capacitors Can Cause Overvoltage Transients” for a detailed discussion of this problem. Always use an oscilloscope to check the voltage waveforms at the USBIN and DCIN pins during USB and wall adapter hot-plug events to ensure that overvoltage transients have been adequately removed. Reverse Polarity Input Voltage Protection In some applications, protection from reverse polarity voltage on the input supply pins is desired. If the supply voltage is high enough, a series blocking diode can be used. In other cases where the voltage drop must be kept low, a P-channel MOSFET can be used (as shown in Figure 6). DRAIN-BULK DIODE OF FET WALL ADAPTER LTC4097 DCIN 4097 F06 Figure 6. Low Loss Input Reverse Polarity Protection 4097f 18 LTC4097 PACKAGE DESCRIPTION DDB Package 12-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1723 Rev Ø) 0.64 ± 0.05 (2 SIDES) 0.70 ± 0.05 2.55 ± 0.05 1.15 ± 0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.45 BSC 2.39 ± 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0 – 0.05 PIN 1 BAR TOP MARK (SEE NOTE 6) 2.00 ± 0.10 (2 SIDES) 0.64 ± 0.10 (2 SIDES) 6 0.23 ± 0.05 2.39 ± 0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD 3.00 ± 0.10 (2 SIDES) R = 0.05 TYP R = 0.115 TYP 7 0.40 ± 0.10 12 1 PIN 1 R = 0.20 OR 0.25 × 45° CHAMFER (DDB12) DFN 0106 REV Ø 0.200 REF 0.75 ± 0.05 0.45 BSC NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 4097f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 19 LTC4097 RELATED PARTS PART NUMBER LTC3455 LTC4053 LTC4054/LTC4054X LTC4055 LTC4058/LTC4058X LTC4061 LTC4061-4.4 LTC4062 LTC4065/LTC4065A LTC4066 LTC4068/LTC4068X LTC4069 LTC4075 DESCRIPTION Dual DC/DC Converter with USB Power Management and Li-Ion Battery Charger USB Compatible Monolithic Li-Ion Battery Charger Standalone Linear Li-Ion Battery Charger with Integrated Pass Transistor in ThinSOTTM USB Power Controller and Battery Charger Standalone 950mA Lithium-Ion Charger in DFN COMMENTS Efficiency >96%, Accurate USB Current Limiting (500mA/100mA), 4mm × 4mm QFN-24 Package Standalone Charger with Programmable Timer, Up to 1.25A Charge Current Thermal Regulation Prevents Overheating, C/10 Termination, C/10 Indicator, Up to 800mA Charge Current Charges Single-Cell Li-Ion Batteries Directly from USB Port, Thermal Regulation, 4mm × 4mm QFN-16 Package C/10 Charge Termination, Battery Kelvin Sensing, ±7% Charge Accuracy Standalone Li-Ion Charger with Thermistor Interface 4.2V, ±0.35% Float Voltage, Up to 1A Charge Current, 3mm × 3mm DFN-10 Package Standalone Li-Ion Charger with Thermistor Interface 4.4V, ±0.4% Float Voltage, Up to 1A Charge Current, 3mm × 3mm DFN-10 Package Standalone Li-Ion Charger with Micropower Comparator Standalone 750mA Li-Ion Charger in 2mm × 2mm DFN USB Power Controller and Li-Ion Linear Battery Charger with Low-Loss Ideal Diode Standalone Linear Li-Ion Battery Charger with Programmable Termination Standalone Li-Ion Battery Charger with NTC Thermistor Input in 2mm × 2mm DFN Dual Input Standalone Li-Ion Battery Charger 4.2V, ±0.35% Float Voltage, Up to 1A Charge Current, 3mm × 3mm DFN-10 Package 4.2V, ±0.6% Float Voltage, Up to 750mA Charge Current, 2mm × 2mm DFN-6 Package Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and Wall Adapter, Low-Loss (50Ω) Ideal Diode, 4mm × 4mm QFN-24 Package Charge Current up to 950mA, Thermal Regulation, 3mm × 3mm DFN-8 Package 4.2V, ±0.6% Float Voltage, Up to 750mA Charge Current, Timer Termination + C/10 Detection Output Charges Single-Cell Li-Ion Batteries from Wall Adapter and USB Inputs with Automatic Input Power Detection and Selection, 950mA Charger Current, Thermal Regulation, C/X Charge Termination, 3mm × 3mm DFN Package Charges Single-Cell Li-Ion Batteries from Wall Adapter and USB Inputs with Automatic Input Power Detection and Selection, 950mA Charger Current, Thermal Regulation, C/X Charge Termination, 3mm × 3mm DFN Package Charges Single-Cell Li-Ion Batteries from Wall Adapter and USB Inputs with Automatic Input Power Detection and Selection, 950mA Charger Current, Thermal Regulation, C/10 Charge Termination, 3mm × 3mm DFN Package Charges Single-Cell Li-Ion Batteries Directly from a USB Port, Thermal Regulation, 200mΩ Ideal Diode with