LTC4075HVXEDD

FEATURES ■ ■ LTC4075HVX High Voltage Dual Input Li-Ion/Polymer Battery Charger DESCRIPTION The LTC®4075HVX is a standalone linear charger that is capable of charging a single-cell Li-Ion/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. The LTC4075HVX features a maximum 22V rating for both wall adapter and USB inputs although charging stops if the selected power source exceeds the overvoltage limit. 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 LTC4075HVX terminates the charge cycle when the charge current drops below the programmed termination threshold after the final float voltage is reached. Other features include automatic recharge, undervoltage lockout, charge status outputs, and “power present” status outputs to indicate the presence of wall adapter or USB power. No trickle charge allows full current from the charger when a load is connected directly to the battery. , 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, 6700364. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 22V Maximum Voltage for Wall Adapter and USB Inputs Charge Single-Cell Li-Ion Batteries from Wall Adapter and USB Inputs Automatic Input Power Detection and Selection Charge Current Programmable up to 950mA from Wall Adapter Input Overvoltage Lockout for Wall Adapter and USB Inputs No External MOSFET, Sense Resistor or Blocking Diode Needed Thermal Regulation Maximizes Charge Rate Without Risk of Overheating* Preset Charge Voltage with ±0.35% Accuracy Programmable Charge Current Termination 40μA USB Suspend Current in Shutdown Independent “Power Present” Status Outputs Charge Status Output Automatic Recharge Available in a Thermally Enhanced, Low Profile (0.75mm) 10-Lead (3mm × 3mm) DFN Package APPLICATIONS ■ ■ ■ ■ Cellular Telephones Handheld Computers Portable MP3 Players Digital Cameras TYPICAL APPLICATION Dual Input Battery Charger for Single-Cell Li-Ion WALL ADAPTER USB PORT 1μF 1μF LTC4075HVX DCIN USBIN IUSB ITERM GND 2k 1% 4075hvx TA01 Charge Current vs Supply Voltage 900 800 700 600 IBAT (mA) CHARGE FROM DCIN 800mA (WALL) 500mA (USB) RIDC = 1.24k RIUSB = 2k VBAT = 3.5V BAT + 2k IDC 1% 1.24k 1% 4.2V SINGLE CELL Li-Ion BATTERY 500 400 300 200 100 0 2 3 4 5 6 7 8 SUPPLY VOLTAGE (V) 19 20 CHARGE FROM USBIN 4075hvx TA01b 4075hvxf 1 LTC4075HVX ABSOLUTE MAXIMUM RATINGS (Note 1) PACKAGE/ORDER INFORMATION TOP VIEW USBIN IUSB ITERM PWR CHRG 1 2 3 4 5 11 10 DCIN 9 BAT 8 IDC 7 USBPWR 6 ENABLE Input Supply Voltage (DCIN, USBIN) ............–0.3 to 22V ENABLE, ⎯C⎯H⎯R⎯G, ⎯P⎯W⎯R, USBPWR, BAT ............–0.3 to 6V IDC, IUSB, ITERM Pin Current .................................1mA DCIN, USBIN, BAT Pin Current ....................................1A BAT Short-Circuit Duration............................Continuous Maximum Junction Temperature .......................... 125°C Operating Temperature Range (Note 2) ... –40°C to 85°C Storage Temperature Range................... –65°C to 125°C DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 40°C/W (Note 3) EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER LTC4075HVXEDD DD PART MARKING LCQM 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 Operating Supply Voltage Operating 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 unless otherwise noted. CONDITIONS ● ● MIN 4.3 4.3 TYP MAX 5.5 5.5 UNITS V V μA μA μA μA μA μA μA μA μA V V mA mA mA μA μA μA V V Charge Mode (Note 4), RIDC = 10k Standby Mode; Charge Terminated Shutdown Mode (ENABLE = 5V) Overvoltage Mode (VDCIN = 10V) Charge Mode (Note 5), RIUSB = 10k, VDCIN = 2V Standby Mode; Charge Terminated, VDCIN = 2V Shutdown (VDCIN = 2V, ENABLE = 0V) Overvoltage Mode (VUSBIN = 10V) VDCIN > VUSBIN IBAT = 1mA IBAT = 1mA, 0°C < TA < 85°C RIDC = 1.25k, Constant-Current Mode RIUSB = 2.1k, Constant-Current Mode RIDC = 10k or RIUSB = 10k Standby Mode, Charge Terminated Shutdown Mode (Charger Disabled) Sleep Mode (VDCIN = 0V, VUSBIN = 0V) Constant-Current Mode Constant-Current Mode RITERM = 1k RITERM = 2k RITERM = 10k RITERM = 20k ● ● 350 70 40 70 350 70 40 70 23 4.185 4.165 4.2 4.2 800 476 100 –7.5 –7.5 –7.5 1 1 800 120 80 140 800 120 80 140 40 4.215 4.235 855 510 107 –12 –12 –12 IUSBIN USBIN Supply Current ● ● VFLOAT IBAT Regulated Output (Float) Voltage BAT Pin Current ● ● ● 745 443 93 VIDC VIUSB ITERMINATE IDC Pin Regulated Voltage IUSB Pin Regulated Voltage Charge Current Termination Threshold ● ● ● ● 85 42 8 3.5 100 50 10 5 115 58 12 6.5 mA mA mA mA 4075hvxf 2 LTC4075HVX ELECTRICAL CHARACTERISTICS VUVDC VUVUSB VOVDC VOVUSB VASD-DC VASD-USB VENABLE RENABLE VOL ΔVRECHRG tRECHRG tTERMINATE RON-DC RON-USB TLIM DCIN Undervoltage Lockout Voltage USBIN Undervoltage Lockout Voltage DCIN Overvoltage Lockout Voltage USBIN Overvoltage Lockout Voltage VDCIN – VBAT Lockout Threshold VUSBIN – VBAT Lockout Threshold ENABLE Input Threshold Voltage ENABLE Pulldown Resistance Output Low Voltage (⎯C⎯H⎯R⎯G, ⎯P⎯W⎯R, USBPWR) Recharge Battery Threshold Voltage Recharge Comparator Filter Time Termination Comparator Filter Time Power FET “ON” Resistance (Between DCIN and BAT) Power FET “ON” Resistance (Between USBIN and BAT) Junction Temperature in ConstantTemperature Mode ISINK = 5mA VFLOAT – VRECHRG, 0°C < TA < 85°C VBAT from High to Low IBAT Drops Below Termination Threshold 90 2.25 1 ● The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 5V, VUSBIN = 5V unless otherwise noted. From Low to High Hysteresis From Low to High Hysteresis From Low to High Hysteresis From Low to High Hysteresis VDCIN from Low to High, VBAT = 4.2V VDCIN from High to Low, VBAT = 4.2V VUSBIN from Low to High VUSBIN from High to Low 4 3.8 5.8 5.8 70 10 70 10 0.6 1 4.15 190 3.95 170 6 185 6 185 120 40 120 40 0.9 2 0.12 125 4.1 1.6 600 700 125 4.3 4.1 6.2 6.2 170 70 170 70 1.2 3.5 0.35 160 6.75 2.4 V mV V mV V mV V mV mV mV mV mV V MΩ V mV ms ms mΩ mΩ °C 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 LTC4075HVX 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 backside of the package to the PC board will result in a thermal resistance much higher than 40°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. 4075hvxf 3 LTC4075HVX TYPICAL PERFORMANCE CHARACTERISTICS Regulated Output (Float) Voltage vs Charge Current 4.26 4.24 4.22 VFLOAT (V) VFLOAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 0 100 200 300 400 500 600 700 800 900 IBAT (mA) 4075hvx G01 TA = 25°C unless otherwise noted. IDC Pin Voltage vs Temperature (Constant-Current Mode) 1.008 1.006 1.004 1.002 VIDC (V) 1.000 0.998 0.996 0.994 VDCIN = 5V Regulated Output (Float) Voltage vs Temperature 4.220 VDCIN = VUSBIN = 5V 4.215 4.210 VDCIN = VUSBIN = 5V RIDC = 1.24k 4.205 4.200 4.195 4.190 4.185 4.180 –10 10 30 50 TEMPERATURE (°C) 70 90 RIDC = RIUSB = 2k 0.992 –10 10 30 50 TEMPERATURE (°C) 70 90 4075hvx G02 4075hvx G03 IUSB Pin Voltage vs Temperature (Constant-Current Mode) 1.008 1.006 1.004 IBAT (mA) VIUSB (V) 1.002 1.000 0.998 0.996 0.994 0.992 –10 10 30 50 TEMPERATURE (°C) 70 90 VUSBIN = 5V 900 800 700 600 500 400 300 200 100 0 Charge Current vs IDC Pin Voltage VDCIN = 5V RIDC = 1.24k 900 800 Charge Current vs IUSB Pin Voltage VUSBIN = 5V RIUSB = 1.24k 700 600 IBAT (mA) 500 400 300 200 RIUSB = 2k RIDC = 2k RIDC = 10k RIUSB = 10k 100 0 1.2 0 0.2 0.4 0.6 0.8 VIUSB (V) 1.0 1.2 0 0.2 0.4 0.6 0.8 VIDC (V) 1.0 4075hvx G04 4075hvx G05 4075hvx G06 ⎯P⎯W⎯R Pin I-V Curve 60 50 40 30 20 10 0 0 1 2 3 VPWR (V) 4075hvx G07 ⎯C⎯H⎯R⎯G Pin I-V Curve 60 50 40 ICHRG (mA) 30 20 10 0 4 5 6 0 1 2 3 VCHRG (V) 4075hvx G08 USBPWR Pin I-V Curve 60 50 40 30 20 10 0 4 5 6 0 1 2 3 4 VUSBPWR (V) 5 6 VDCIN = 5V, VUSBIN = 0V VDCIN = VUSBIN = 5V VDCIN = VUSBIN = 5V IUSBPWR (mA) IPWR (mA) 4075hvx G09 4075hvxf 4 LTC4075HVX TYPICAL PERFORMANCE CHARACTERISTICS Charge Current vs Ambient Temperature 900 800 700 600 IBAT (mA) IBAT (mA) RIDC = 2k 500 400 300 200 VDCIN = VUSBIN = 5V 100 VBAT = 4V θJA = 30°C/W 0 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) 4075hvx G10 TA = 25°C unless otherwise noted. Charge Current vs Supply Voltage 900 800 700 600 500 400 300 200 100 0 4.0 4.5 5.0 5.5 6.0 6.5 VDCIN (V) RIDC = 1.24V VBAT = 4V θJA = 30°C/W 7.0 7.5 8.0 200 IBAT (mA) 600 800 1000 Charge Current vs Battery Voltage RIDC = 1.24k 400 0 2.4 VDCIN = VUSBIN = 5V RIDC = 1.25V θJA = 30°C/W 2.7 3.0 3.3 3.6 VBAT (V) 3.9 4.2 4.5 4075hvx G11 4075hvx G12 DCIN Power FET On-Resistance vs Temperature 800 750 700 650 600 550 500 –10 VBAT = 4V IBAT = 200mA 900 850 800 USBIN Power FET On-Resistance vs Temperature VBAT = 4V IBAT = 200mA 1000 980 960 VENABLE (V) 940 920 900 650 600 –10 880 ENABLE Pin Threshold Voltage (On-to-Off) vs Temperature VDCIN = VUSBIN = 5V RDS(ON) (mΩ) RDS(ON) (mΩ) 750 700 10 30 50 TEMPERATURE (°C) 70 90 10 30 50 TEMPERATURE (°C) 70 90 860 –10 10 30 50 TEMPERATURE (°C) 70 90 4075hvx G13 4075hvx G14 4075hvx G15 USBIN Shutdown Current vs Temperature 60 55 50 IUSBIN (μA) 45 40 35 30 25 20 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 VUSBIN = 4.3V VUSBIN = 5V IDCIN (μA) VENABLE = 0V 60 55 50 45 40 35 30 25 DCIN Shutdown Current vs Temperature VENABLE = 5V 2.4 2.3 VDCIN = 5V RENABLE (MΩ) VDCIN = 4.3V –25 0 25 50 TEMPERATURE (°C) 75 100 2.2 2.1 2.0 1.9 1.8 1.7 ENABLE Pin Pulldown Resistance vs Temperature 20 –50 1.6 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4075hvx G16 4075hvx G17 4075hvx G18 4075hvxf 5 LTC4075HVX TYPICAL PERFORMANCE CHARACTERISTICS Undervoltage Lockout Threshold vs Temperature 4.25 4.20 4.15 4.10 VUV (V) VOV (V) 4.05 4.00 3.95 3.90 3.85 –10 10 30 50 TEMPERATURE (°C) 70 90 USBIN UVLO DCIN UVLO 6.00 USBIN OVLO 5.95 5.90 5.85 5.80 –10 DCIN OVLO 6.10 6.05 TA = 25°C unless otherwise noted. Overvoltage Lockout Threshold vs Temperature 10 30 50 TEMPERATURE (°C) 70 90 4075hvx G19 4075hvx G20 Recharge Threshold Voltage vs Temperature 4.11 VDCIN = VUSBIN = 5V 9.0 8.5 4.09 VRECHRG (V) 8.0 4.07 IBAT (μA) 7.5 7.0 4.05 6.5 4.03 –10 Battery Drain Current vs Temperature VDCIN = VUSBIN = NOT CONNECTED VBAT = 4.2V 10 30 50 TEMPERATURE (°C) 70 90 6.0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 4075hvx G21 4075hvx G22 4075hvxf 6 LTC4075HVX PIN FUNCTIONS USBIN (Pin 1): USB Input Supply Pin. This input provides power to the battery charger assuming a voltage greater than VUVUSB and less than VOVUSB is present (typically 3.95V to 6V respectively). However, the DCIN input will take priority if a voltage greater than VUVDC and less than VOVDC is present at DCIN (typically 4.15V to 6V respectively). The USBIN input allows charge currents up to 850mA. This pin should be bypassed with a 1μF capacitor. IUSB (Pin 2): 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 USB input using the following formula: IBAT = VIUSB • 1000 RIUSB ⎯⎯⎯⎯ is completed, CHRG becomes high impedance. This output is capable of driving an LED. ENABLE (Pin 6): Enable Input. When the LTC4075HVX is charging from the DCIN source, a logic low on this pin enables the charger. When the LTC4075HVX is charging from the USBIN source, a logic high on this pin enables the charger. If this input is left floating, an internal 2MΩ pull-down resistor defaults the LTC4075HVX to charge when a wall adapter is applied and to shut down if only the USB source is applied. USBPWR (Pin 7): Open-Drain USB Power Status Output. When the voltage on the USBIN pin is sufficient to begin charging and there is insufficient power at DCIN, the USBPWR pin is high impedance. In all other cases, this pin is pulled low by an internal N-channel MOSFET, provided that there is power present at either DCIN, USBIN, or BAT inputs. This output is capable of driving an LED. IDC (Pin 8): 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 to measure the battery current delivered from the DC input using the following formula: IBAT = VIDC • 1000 RIDC ITERM (Pin 3): 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 = 100 V RITERM When the battery current, IBAT, falls below the termination threshold, charging stops and the ⎯C⎯H⎯R⎯G output becomes high impedance. This pin is internally clamped to approximately 1.5V. Driving this pin to voltages beyond the clamp voltage should be avoided. ⎯P⎯W⎯R (Pin 4): Open-Drain Power Supply Status Output. When the DCIN or USBIN pin voltage is valid to begin charging (i.e. when the supply is greater than the undervoltage lockout threshold, less than the overvoltage lockout threshold and at least 120mV above the battery terminal), the ⎯P⎯W⎯R pin is pulled low by an internal N-channel MOSFET. Otherwise ⎯P⎯W⎯R is high impedance. This output is capable of driving an LED (see Table 1 for more detail). ⎯C⎯H⎯R⎯G (Pin 5): Open-Drain Charge Status Output. When the LTC4075HVX is charging, the ⎯C⎯H⎯R⎯G pin is pulled low by an internal N-channel MOSFET. When the charge cycle BAT (Pin 9): Battery Charger Output. This pin provides charge current to the battery and regulates the final float voltage to 4.2V. DCIN (Pin 10): Wall Adapter Input Supply Pin. This input provides power to the battery charger assuming a voltage greater than VUVDC and less than VOVDC is present (typically 4.15V to 6V respectively). A valid voltage on the DCIN input will always take priority over the USBIN input. The DCIN input allows charge currents up to 950mA. This pin should be bypassed with a 1μF capacitor. Exposed Pad (Pin 11): GND. The exposed backside of the package is ground and must be soldered to PC board ground for electrical connection and maximum heat transfer. 4075hvxf 7 LTC4075HVX BLOCK DIAGRAM DCIN 10 BAT 9 USBIN 1 CC/CV REGULATOR CC/CV REGULATOR 7 USBPWR DC_ENABLE USB_ENABLE CHARGER CONTROL PWR 4 + 4.15V + DCIN UVLO USBIN UVLO – – 3.95V + BAT + – BAT – + 6V + DCIN OVLO USBIN OVLO – – 6V ENABLE 6 2M 0.9V + – + – TDIE THERMAL REGULATION 125°C 4.075V + – RECHARGE BAT CHRG 5 – TERMINATION 0.1V IBAT/1000 IBAT/1000 IBAT/1000 + GND 11 3 RITERM ITERM 8 RIDC IDC 2 RIUSB IUSB 4075hvx BD 4075hvxf 8 LTC4075HVX OPERATION The LTC4075HVX is designed to efficiently manage charging of 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 950mA of charge current from the wall adapter supply or up to 850mA of charge current from the USB supply with a final float voltage accuracy of ±0.6%. The LTC4075HVX has two internal P-channel power MOSFETs and thermal regulation circuitry. No blocking diodes or external sense resistors are required. Power Source Selection The LTC4075HVX can charge a battery from either the wall adapter input or the USB port input. The LTC4075HVX automatically senses the presence of voltage at each input. If both power sources are present, the LTC4075HVX defaults to the wall adapter source provided a valid voltage is present at the DCIN input. “Valid voltage” is defined as: • Supply voltage is greater than the undervoltage lockout threshold and less than the overvoltage lockout threshold. • Supply voltage is greater than the battery voltage by 40mV. The open drain power status outputs (⎯P⎯W⎯R and USBPWR) indicate which power source has been selected. Table 1 describes the behavior of these status outputs. Programming and Monitoring Charge Current The charge current delivered to the battery from the wall adapter or USB supply is programmed using a single resistor from the IDC or IUSB pin to ground. Both program resistors and charge currents (ICHRG) are calculated using the following equations: RIDC = 1000 V ICHRG−DC , ICHRG−DC = 1000 V RIDC 1000 V 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, (ch arg ing from USB sup ply) RIUSB Programming Charge Termination The charge cycle terminates when the charge current falls below the programmed termination threshold level 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 = 100 V ITERMINATE , ITERMINATE = 100 V RITERM 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 1.6ms), charging is terminated. The charge current is latched off and the LTC4075HVX 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 1.6ms 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 LTC4075HVX terminates the charge cycle and stops providing current out of the BAT pin. In this state, any load on the BAT pin must be supplied by the battery. RIUSB = 1000 V ICHRG−USB , ICHRG−USB = *Any external sources that hold the ITERM pin above 100mV will prevent the LTC4075HVX from terminating a charge cycle. 4075hvxf 9 LTC4075HVX OPERATION Automatic Recharge In standby mode, the charger sits idle and monitors the battery voltage using a comparator with a 4.1ms filter time (tRECHRG). A charge cycle automatically restarts when the battery voltage falls below 4.075V (which corresponds to approximately 80% to 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. Manual Shutdown The ENABLE pin has a 2MΩ pull-down resistor to GND. The definition of this pin depends on which source is supplying power. When the wall adapter input is supplying power, logic low enables the charger and logic high disables it Table 1. Power Source Selection VUSBIN < 3.95V or VUSBIN < BAT + 50mV ENABLE HIGH LOW or No Connect No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z Charging from DCIN source. ⎯P⎯W⎯R: LOW USBPWR: LOW ⎯C⎯H⎯R⎯G: LOW No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z VDCIN < 4.15V or No Charging. VDCIN < BAT + 50mV ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z 6V > VDCIN > 4.15V and VDCIN > BAT + 50mV No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z 6V > VUSBIN > 3.95V and VUSBIN > BAT + 50mV HIGH Charging from USBIN source. ⎯P⎯W⎯R: LOW USBPWR: Hi-Z ⎯C⎯H⎯R⎯G: LOW No Charging. ⎯PW⎯R: Hi-Z ⎯ USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z No Charging. ⎯PW⎯R: Hi-Z ⎯ USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z LOW or No Connect No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z Charging from DCIN source. ⎯P⎯W⎯R: LOW USBPWR: LOW ⎯C⎯H⎯R⎯G: LOW No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z 22V > VUSBIN > 6V HIGH No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z No Charging. ⎯PW⎯R: Hi-Z ⎯ USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z No Charging. ⎯PW⎯R: Hi-Z ⎯ USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z LOW or No Connect No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z Charging from DCIN source. ⎯P⎯W⎯R: LOW USBPWR: LOW ⎯C⎯H⎯R⎯G: LOW No Charging. ⎯P⎯W⎯R: Hi-Z USBPWR: LOW ⎯C⎯H⎯R⎯G: Hi-Z (the internal pull-down resistor defaults the charger to the charging state). The opposite is true when the USB input is supplying power; logic low disables the charger and logic high enables it (the default is the shutdown state). The DCIN input draws 40μA when the charger is in shutdown mode. The USBIN input draws 40μA during shutdown if no voltage is applied to DCIN, but draws only 23μA when VDCIN provides valid voltage (see Table 1). Status Indicators The charge status open drain output (⎯C⎯H⎯R⎯G) has two states: pull-down and high impedance. The pull-down state indicates that the LTC4075HVX is in a charge cycle. Once the charge cycle has terminated or the LTC4075HVX is disabled, the pin state becomes high impedance. The power supply status open drain output (⎯P⎯W⎯R) has two states: pull-down and high impedance. The pull-down state indicates that power is present at either DCIN or USBIN. This output is strong enough to drive an LED. If no valid voltage is applied at either pin, the ⎯P⎯W⎯R pin is high impedance, indicating that the LTC4075HVX lacks valid input voltage (see Table 1) to charge the battery. 22V > VDCIN > 6V 4075hvxf 10 LTC4075HVX OPERATION The USB power status open drain output (USBPWR) has two states: pull-down and high impedance. The high impedance state indicates that the LTC4075HVX is being powered from the USBIN input. The pull-down state indicates that the charger is either powered from DCIN or is in a UVLO or an OVLO condition (see Table 1). Thermal Limiting An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise DCIN POWER REMOVED above a preset value of approximately 125°C. This feature protects the LTC4075HVX 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. DFN package power considerations are discussed further in the Applications Information section. USB POWER REMOVED NO POWER POWER APPLIED ENABLE = LOW ENABLE = HIGH YES DCIN > 4.15V and DCIN > BAT NO 6V > DCIN > 4.15V and DCIN > BAT YES CHARGE MODE (DCIN) FULL CURRENT CHRG STATE: PULLDOWN IBAT < ITERMINATE IN VOLTAGE MODE STANDBY MODE (DCIN) BAT < 4.075V NO CHARGE CURRENT CHRG STATE: Hi-Z NO NO 6V > USBIN > 3.95V and USBIN > BAT YES CHARGE MODE (USBIN) FULL CURRENT CHRG STATE: PULLDOWN IBAT < ITERMINATE IN VOLTAGE MODE STANDBY MODE (USBIN) BAT < 4.075V NO CHARGE CURRENT CHRG STATE: Hi-Z SHUTDOWN MODE (DCIN) CHRG STATE: Hi-Z SHUTDOWN MODE (USBIN) CHRG STATE: Hi-Z 4075hvx F01 Figure 1. LTC4075HVX State Diagram of a Charge Cycle 4075hvxf 11 LTC4075HVX APPLICATIONS INFORMATION Using a Single Charge Current Program Resistor The LTC4075HVX can program the wall adapter charge current and USB charge current independently using two program resistors, RIDC and RIUSB. Figure 2 shows a charger circuit that sets the wall adapter charge current to 800mA and the USB charge current to 500mA. 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 3 shows a charger circuit that uses one charge current program resistor. WALL ADAPTER USB PORT 1μF 1μF RIUSB 2k 1% RIDC 1.24k 1% LTC4075HVX DCIN USBIN IUSB IDC ITERM GND RITERM 1k 1% 4075hvx F02 Stability Considerations The constant-voltage mode feedback loop is stable without any compensation provided a battery is connected to the charger output. However, a 1μF 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 20k (ICHRG = 50mA); however, additional capacitance on these nodes reduces the maximum allowed program resistor. Power Dissipation When designing the battery charger circuit, it is not necessary to design for worst-case power dissipation scenarios because the LTC4075HVX automatically reduces the charge current during high power conditions. The conditions that cause the LTC4075HVX 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 charger MOSFET. Thus, the power dissipation is calculated to be: PD = (VIN – VBAT) • IBAT PD is the dissipated power, VIN 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 = 125°C – PD • θJA TA = 125°C – (VIN – VBAT) • IBAT • θJA Example: An LTC4075HVX operating from a 5V wall adapter (on the DCIN input) is programmed to supply 800mA full-scale current to a discharged Li-Ion battery with a voltage of 3.3V. 800mA (WALL) 500mA (USB) BAT + Figure 2. Dual Input Charger with Independant Charge Currents LTC4075HVX DCIN USBIN 1μF 1μF RISET 2k 1% IUSB IDC ITERM GND RITERM 1k 1% 4075hvx F03 WALL ADAPTER USB PORT 500mA BAT + Figure 3. Dual Input Charger Circuit. The Wall Adapter Charge Current and USB Charge Current are Both Programmed to be 500mA In this circuit, the programmed charge current from both the wall adapter supply is the same value as the programmed charge current from the USB supply: ICHRG−DC = ICHRG−USB = 1000 V RISET 4075hvxf 12 LTC4075HVX APPLICATIONS INFORMATION Assuming θJA is 40°C/W (see Thermal Considerations), the ambient temperature at which the LTC4075HVX will begin to reduce the charge current is approximately: TA = 125°C – (5V – 3.3V) • (800mA) • 40°C/W TA = 125°C – 1.36W • 40°C/W = 125°C – 54.4°C TA = 70.6°C The LTC4075HVX can be used above 70.6°C ambient, but the charge current will be reduced from 800mA. The approximate current at a given ambient temperature can be approximated by: IBAT = 125°C – TA ( VIN – VBAT) • θ JA Input Capacitor Selection When an input supply is connected to a portable product, the inductance of the cable and the high-Q ceramic input capacitor form an L-C resonant circuit. While the LTC4075HVX is capable of withstanding input voltages as high as 22V, if the input cable does not have adequate mutual coupling or if there is not much impedance in the cable, it is possible for the voltage at the input of the product to reach twice the input voltage before it settles out. To prevent excessive voltage from damaging the LTC4075HVX during a hot insertion, it is best to have a low voltage coefficient capacitor at the input pins to the LTC4075HVX. This is achievable by selecting an X5R or X7R ceramic capacitor that has a higher voltage rating than that required for the application. For example, if the maximum expected input voltage is 15V, a 25V X5R 1μF capacitor would be a better choice than the smaller 16V X5R capacitor. Using a tantalum capacitor or an aluminum electrolytic capacitor for input bypassing, or paralleling with a ceramic capacitor will also reduce voltage overshoot during a hot insertion. Ceramic capacitors with Y5V or Z5U dielectrics are not recommended. Alternatively, the following soft connect circuit can be employed (as shown in Figure 4). DCIN/USBIN 15V INPUT INPUT CABLE C2 100nF R1 39k C1 1μF MN1 GND 4075hvx F04 ample, a correctly soldered LTC4075HVX can deliver over 800mA to a battery from a 5V supply at room temperature. Without a good backside thermal connection, this number would drop to much less than 500mA. Using the previous example with an ambient temperature of 80°C, the charge current will be reduced to approximately: IBAT = 125°C – 80°C 45°C = (5V – 3.3V) • 40°C / W 68°C / A IBAT = 662mA It is important to remember that LTC4075HVX 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 125°C. 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 LTC4075HVX DFN package is properly soldered to the PC board ground. When correctly soldered to a 2500mm2 double sided 1oz copper board, the LTC4075HVX has a thermal resistance of approximately 40°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 40°C/W. As an ex- LTC4075HVX Figure 4. Input Soft Connect Circuit 4075hvxf 13 LTC4075HVX APPLICATIONS INFORMATION In this circuit, capacitor C2 holds MN1 off when the cable is first connected. Eventually C2 begins to charge up to the USB input voltage applying increasing gate drive to MN1. The long time constant of R1 and C1 prevent the current from rapidly building up in the cable thus dampening out any resonant overshoot. Reverse Polarity Input Voltage Protection In some applications, protection from reverse polarity voltage on the input supply pins is desired. With sufficient supply voltage, 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 5). DRAIN-BULK DIODE OF FET WALL ADAPTER LTC4075HVX DCIN 4075hvx F05 Figure 5. Low Loss Reverse Polarity Protection 4075hvxf 14 LTC4075HVX PACKAGE DESCRIPTION DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) R = 0.115 TYP 6 0.675 ± 0.05 0.38 ± 0.10 10 3.50 ± 0.05 1.65 ± 0.05 2.15 ± 0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 2.38 ± 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 TOP MARK (SEE NOTE 6) 3.00 ± 0.10 (4 SIDES) 1.65 ± 0.10 (2 SIDES) (DD10) DFN 1103 5 0.200 REF 0.75 ± 0.05 2.38 ± 0.10 (2 SIDES) 1 0.25 ± 0.05 0.50 BSC 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 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 4075hvxf 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. 15 LTC4075HVX TYPICAL APPLICATION Full Featured Li-Ion Charger WALL ADAPTER USB POWER LTC4075HVX DCIN USBIN 1μF 1μF PWR IUSB IDC 2.1k 1% 1.24k 1% CHRG ITERM GND 1k 1% 4075hvx TA02 800mA (WALL) 475mA (USB) 1k 1k 4.2V 1-CELL Li-Ion BATTERY BAT + RELATED PARTS PART NUMBER LTC3455 LTC4053 DESCRIPTION Dual DC/DC Converter with USB Power Management and Li-Ion Battery Charger USB Compatible Monolithic Li-Ion Battery Charger 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 4.2V, ±0.35% Float Voltage, Up to 1A Charge Current Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and Wall Adapter, Low-Loss (50mΩ) Ideal Diode, 4mm × 4mm QFN-24 Package Charge Current up to 950mA, Thermal Regulation, 3mm × 3mm DFN-8 Package 950mA Charger Current, Thermal Regulation, C/X Charge Termination, USB Charge Current Set Via Resistor, 3mm × 3mm DFN Package 950mA Charger Current, Thermal Regulation, C/X Charge Termination, Fixed C or C/5 USB Charge Current for Low Power USB Operation, 3mm × 3mm DFN Package 950mA Charger Current, Thermal Regulation, C/X Charge Termination, Programmable C or C/x USB Charge Current for Low Power USB Operation, Fixed C/10 Wall Adapter and C/10 or C/2 Charge Current Termination, 3mm × 3mm DFN Package Charges Single-Cell Li-Ion Batteries Directly from USB Port, Thermal Regulation, 200mΩ Ideal Diode with