LTC4413EDD2

FEATURES ■ ■ LTC4413-1/LTC4413-2 Dual 2.6A, 2.5V to 5.5V Fast Ideal Diodes in 3mm × 3mm DFN DESCRIPTION The LTC®4413-1 and LTC4413-2 each contain two monolithic ideal diodes, each capable of supplying up to 2.6A from input voltages between 2.5V and 5.5V. The ideal diodes use a 100mΩ P-channel MOSFET to independently connect INA to OUTA and INB to OUTB. During normal forward operation, the voltage drops across each of these diodes are regulated to as low as 18mV. Quiescent current is less than 80μA for diode currents up to 1A. If either of the output voltages exceeds its respective input voltage, that MOSFET is turned off and less than 1μA of reverse current flows from OUT to IN. Maximum forward current in each MOSFET is limited to a constant 2.6A and internal thermal limiting circuits protect the part during fault conditions. An internal overvoltage protection sensor detects when a voltage exceeds the LTC4413-2 absolute maximum voltage tolerance. Two active-high control pins independently turn off the two ideal diodes contained within the LTC4413-1/LTC4413-2. When the selected channel is reverse biased, or the LTC4413-1/LTC4413-2 is put into low power standby, the status signal is pulled low by an 11μA open drain. The LTC4413-1/LTC4413-2 are housed in a 10-lead 3mm × 3mm DFN package. , LT LTC and LTM are registered trademarks of Linear Technology Corporation. , PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 2-Channel Ideal Diode OR’ing or Load Sharing Low Loss Replacement for PowerPathTM OR’ing Diodes Fast Response Replacement for LTC4413 Low Forward On Resistance (140mΩ Max at 3.6V) Low Reverse Leakage Current Low Regulated Forward Voltage (18mV Typ) Overvoltage Protection Sensor with Drive Output for an External P-Channel MOSFET (LTC4413-2 Only) 2.5V to 5.5V Operating Range 2.6A Maximum Forward Current Internal Current Limit Protection Internal Thermal Protection Status Output to Indicate if Selected Channel is Conducting Programmable Channel On/Off Low Profile (0.75mm) 10-Lead 3mm × 3mm DFN Package APPLICATIONS ■ ■ ■ ■ ■ Battery and Wall Adapter Diode OR’ing in Handheld Products Backup Battery Diode OR’ing Power Switching USB Peripherals Uninterruptable Supplies TYPICAL APPLICATION Automatic Switchover from a Battery to a Wall Adapter FDR8508 WALL ADAPTER INPUT INA 0.1μF 1Ω 10μF OUTA POWER LOSS (mW) 470k IDEAL ENBA STAT LTC4413-2 GND OVI ENBB INB IDEAL OVP OUTB STAT 500 VCC 700 600 Power Loss vs Load LTC4413-1 400 300 1N5817 200 100 0 0 500 OVP TO LOAD 4.7μF 441312 TA01a BAT + STAT IS HIGH WHEN WALL ADAPTER IS SUPPLYING LOAD CURRENT OVP IS HIGH WHEN WALL ADAPTER VOLTAGE > 6V 1000 1500 2000 LOAD (mA) 2500 3000 441312 TA01b 441312fb 1 LTC4413-1/LTC4413-2 ABSOLUTE MAXIMUM RATINGS (Note 1) INA, INB, OUTA, OUTB, STAT, ENBA, ENBB Voltage .................................... –0.3V to 6V OVI, OVP Voltage ....................................... –0.3V to 13V Operating Temperature Range.................. –40°C to 85°C Storage Temperature Range................... –65°C to 125°C Continuous Power Dissipation ..........................1500mW (Derate 25mW/°C Above 70°C) PIN CONFIGURATION TOP VIEW INA ENBA GND ENBB INB 1 2 3 4 5 11 10 OUTA 9 STAT 8 NC 7 NC 6 OUTB INA ENBA GND ENBB INB 1 2 3 4 5 11 TOP VIEW 10 OUTA 9 STAT 8 OVI 7 OVP 6 OUTB DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH LTC4413EDD1#PBF LTC4413EDD2#PBF LEAD BASED FINISH LTC4413EDD1 LTC4413EDD2 TAPE AND REEL LTC4413EDD1#TRPBF LTC4413EDD2#TRPBF TAPE AND REEL LTC4413EDD1#TR LTC4413EDD2#TR PART MARKING LCPP LCPQ PART MARKING LCPP LCPQ PACKAGE DESCRIPTION 10-Lead (3mm × 3mm) Plastic DFN 10-Lead (3mm × 3mm) Plastic DFN PACKAGE DESCRIPTION 10-Lead (3mm × 3mm) Plastic DFN 10-Lead (3mm × 3mm) Plastic DFN TEMPERATURE RANGE –40°C to 85°C –40°C to 85°C TEMPERATURE RANGE –40°C to 85°C –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ ELECTRICAL CHARACTERISTICS SYMBOL VIN, VOUT UVLO IQF IQRIN IQRGND PARAMETER The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 6) CONDITIONS ● ● ● ● ● MIN 2.5 TYP MAX 5.5 2.45 UNITS V V V μA μA μA Operating Supply Range for Channel A or B VIN and/or VOUT Must be in This Range for Proper Operation UVLO Turn-On Rising Threshold UVLO Turn-Off Falling Threshold Quiescent Current in Forward Regulation, Measured via GND Current Drawn from or Sourced into IN when VOUT is greater than VIN Quiescent Current While in Reverse Turn-Off, Measured via GND Max (VINA, VINB, VOUTA, VOUTB) Max (VINA, VINB, VOUTA, VOUTB) VINA = 3.6V, IINA = 100mA, VINB = 0V, IINB = 0mA (Note 3) VIN = 3.6V, VOUT = 5.5V (Note 6) VINA = VINB = 0V, VOUTB = VOUTA = 5.5V, VSTAT = 0V 1.7 40 –1 2.5 28 58 4.5 36 441312fb 2 LTC4413-1/LTC4413-2 ELECTRICAL CHARACTERISTICS SYMBOL IQROUTB PARAMETER Quiescent Current While in Reverse Turn-Off. Current Drawn from VOUTA when OUTB Supplies Chip Power Quiescent Current with Both ENBA and ENBB High Reverse Turn-Off Voltage (VOUT – VIN) Forward Voltage Drop (VIN – VOUT) at IOUT = –1mA On-Resistance, RFWD Regulation (Measured as ΔV/ΔI) On-Resistance, RON Regulation (Measured as V/I at IIN = 1A) PowerPath Turn-On Time PowerPath Turn-Off Time The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 6) CONDITIONS VINA = VINB = 0V, VOUTA = 3.6V, VOUTB = 5.5V ● MIN TYP 3.5 MAX 6.5 UNITS μA IQOFF VRTO VFWD RFWD RON tON tOFF VINA = VINB = 3.6V, VENBA = VENBB = 1V VIN = 3.6V VIN = 3.6V VIN = 3.6V, IOUT = –100mA to –500mA (Note 5) VIN = 3.6V, IIN = 1A (Note 5) VIN = 3.6V, from ENB Falling to IOUT Ramp Starting VIN = 3.6V, from ENB Rising with IIN = 100mA Falling to 0mA VINA OR B = 3.6V (Note 5) VINA OR B = 3.6V, IOUT = 1.8A (Note 5) ● ● ● 28 –5 18 100 140 11 2 38 10 24 140 200 μA mV mV mΩ mΩ μs μs Short-Circuit Response IOC IQOC STAT Output ISOFF ISON tS(ON) tS(OFF) ENB Inputs VENBIH VENBIL VENBHYST IENB VOVIH VOVIL VOVID IOVI ENB Inputs Rising Threshold Voltage ENB Inputs Falling Threshold Voltage ENB Input Hysteresis ENB Inputs Pull-Down Current OVI Input Rising Threshold Voltage OVI Input Falling Threshold Voltage OVI-OVP Voltage Drop OVI Bias Current VENB Rising VENB Falling VENBHYST = (VENBIH – VENBIL) VOUT < VIN = 3.6V, VENB < VIL VOVI Rising VOVI Falling VOVI = 8V, No Load at OVP VOVI = 8V 5.4 ● ● ● Current Limit Quiescent Current While in Overcurrent Operation STAT Off Current STAT Sink Current STAT Pin Current Turn-On Time STAT Pin Current Turn-Off Time 1.8 100 130 A μA Shut Down VIN > VOUT, VCTL < VIL, TJ < 135°C, IOUT < IMAX VIN = 3.6V, from ENB Falling VIN = 3.6V, from ENB Rising ● ● –1 7 0 11 1.8 0.8 540 1 13 μA μA μs μs 600 mV mV mV 400 2 460 90 3 5.9 5.6 100 80 4 6.2 μA V V mV μA OVI Input (LTC4413-2 Only) 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 LTC4413-1/LTC4413-2 are guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 85°C ambient operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Quiescent current increases with diode current: refer to plot of IQF vs IOUT. Note 4: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Overtemperature protection will become active at a junction temperature greater than the maximum operating temperature. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 5: Specification is guaranteed by correlation to wafer-level measurements. Note 6: Unless otherwise specified, current into a pin is positive and current out of a pin is negative. All voltages referenced to GND. 441312fb 3 LTC4413-1/LTC4413-2 TYPICAL PERFORMANCE CHARACTERISTICS IQF vs ILOAD (Log) 120 120°C 100 80 IQF (μA) 60 40 20 0 1 10 100 LOAD (mA) 1000 10000 441312 G01 IQF vs ILOAD (Linear) 120 120°C 100 80 IQF (μA) 60 40 20 0 80°C 40°C 0°C IQF (μA) –40°C 100 80°C 40°C 0°C –40°C 120 IQF vs Temperature 1A 80 500mA 60 40 20 0 –40 100mA 1mA 0 500 1000 1500 2000 LOAD (mA) 2500 3000 0 40 80 TEMPERATURE (°C) 120 441312 G03 441312 G02 IQF vs VIN 90 80 70 60 IOC (mA) IQF (μA) 50 40 30 20 10 0 2 2.5 3 3.5 4 VIN (V) 441312 G04 IOC vs Temperature 3500 IQF = 1A 3000 2500 IQF = 100mA 2000 1500 UVLO THRESHOLDS (V) 2.20 2.15 2.10 2.05 2.00 UVLO Thresholds vs Temperature RISING FALLING 1.95 1.90 1.85 –40 1000 500 0 –40 4.5 5 5.5 6 0 40 TEMPERATURE (°C) 80 120 441312 G05 0 40 TEMPERATURE (°C) 80 120 441312 G06 UVLO Hystersis vs Temperature 250 600 500 ENB Thresholds vs Temperature 120 100 ENB HYSETERSIS (mV) ENBIH ENBIL 80 60 40 20 ENB Hysteresis vs Temperature UVLO HYSTERESIS (mV) 200 ENBIH/ENBIL (mV) 150 400 300 200 100 0 –40 100 50 0 –40 –20 0 20 40 60 80 TEMPERATURE (°C) 100 120 441312 G07 0 40 80 TEMPERATURE (°C) 120 441312 G08 0 –40 –20 0 20 40 60 80 TEMPERATURE (°C) 100 120 441312 G09 441312fb 4 LTC4413-1/LTC4413-2 TYPICAL PERFORMANCE CHARACTERISTICS RFWD vs VIN and ILOAD = 500mA 80 78 76 RFWD 500mA (mΩ) 74 RFWD (mΩ) 72 70 68 66 64 62 60 2 2.5 3 3.5 4 4.5 VIN (V) 5 0 5.5 6 0 500 1000 1500 2000 LOAD (mA) 2500 0 3000 0 1 10 100 LOAD (mA) 1000 0 10000 441312 G12 VFWD and RFWD vs ILOAD (Linear) 500 120°C 80°C 40°C 0°C –40°C 250 600 500 400 RFWD (mΩ) VFWD (mV) 150 RFWD and VFWD vs ILOAD (Log) 120°C 80°C 40°C 0°C –40°C RFWD 300 200 50 100 VFWD 150 100 50 300 250 200 VFWD (mV) 400 200 VFWD 300 200 RFWD 100 100 441312 G10 441312 G11 VFWD vs ILOAD (Log) 250 120°C 80°C 40°C 0°C –40°C RFWD (mΩ) 120 100 RFWD vs Temperature 1 ILEAK vs Temperature at VREVERSE = 5.5V 200 100mA 80 60 40 1A ILEAK (μA) 500mA 0.1 VFWD (mV) 150 0.01 5.5V 3.6V 100 0.001 50 20 0 –40 0.0001 0 1 10 100 LOAD (mA) 1000 10000 441312 G13 0 40 80 TEMPERATURE (°C) 120 441312 G14 0.00001 –40 –20 0 20 40 60 80 TEMPERATURE (°C) 100 120 441312 G15 ILEAK vs VREVERSE 100 10 1 ILEAK (μA) 0.1 0.01 120°C 80°C 40°C 0°C –40°C Response to 800mA Load Step in IOC) the LTC4413-1/LTC4413-2 fixes the load current to the constant value IOC to protect the device. The characteristics for parameters RFWD, RON, VFWD and IOC are specified with the aid of Figure 1, illustrating the LTC4413-1/LTC4413-2 forward voltage drop versus that of a Schottky. If another supply is provided at VINB, the LTC4413-1/ LTC4413-2 likewise regulate the gate voltage on PB to IOC LTC4413-1 LTC4413-2 SLOPE: 1/RON CURRENT (A) IFWD 1N5817 SLOPE: 1/RFWD maintain the output voltage, VOUTB, just below the input voltage VINB. If this alternate supply, VINB, exceeds the voltage at VINA, the LTC4413-1/LTC4413-2 selects this input voltage as the internal supply (VDD). This second ideal diode operates independently of the first ideal diode function. When an alternate power source is connected to the load at VOUTA (or VOUTB), the LTC4413-1/LTC4413-2 sense the increased voltage at VOUTA, and amplifier A increases the voltage VGATEA, reducing the current through PA. When VOUTA is higher than VINA + VRTO, VGATEA will be pulled up to VDD, turning off PA. The internal power source for the LTC4413-1/LTC4413-2 (VDD) then diverts to draw current from the VOUTA pin, only if VOUTA is larger than VINB (or VOUTB). The system is now in the reverse turn-off mode. Power to the load is being delivered from an alternate supply, and only a small current (ILEAK) is drawn from or sourced to VINA to sense the potential at VINA. When the selected channel of the LTC4413-1/LTC4413-2 is in reverse turn-off mode or both channels are disabled, the STAT pin sinks 11μA of current (ISON) if connected. Channel selection is accomplished using the two ENB pins, ENBA and ENBB. When the ENBA input is asserted (high), PA has its gate voltage pulled to VDD, turning off PA. A 3.5μA pull-down current on the ENB pins ensures a low level at these inputs if left floating. 0 0 VFWD FORWARD VOLTAGE (V) 441312 TA01b Figure 1. The LTC4413 vs the 1N5817 441312fb 9 LTC4413-1/LTC4413-2 OPERATION Overcurrent and Short-Circuit Protection During an overcurrent condition, the output voltage droops as the load current exceeds the amount of current that the LTC4413-1/LTC4413-2 can supply. At the time when an overcurrent condition is first detected, the LTC4413-1/ LTC4413-2 take some time to detect this condition before reducing the current to IOC. For short durations after the output is shorted, until TOC, the current may exceed IOC. The magnitude of this peak short-circuit current can be large depending on the load current immediately before the short circuit occurs. During overcurrent operation, the power consumption of the LTC4413-1/LTC4413-2 is large, and is likely to cause an overtemperature condition as the internal die temperature exceeds the thermal shutdown temperature. Overtemperature Protection The overtemperature condition is detected when the internal die temperature increases beyond 150°C. An overtemperature condition will cause the gate amplifiers (A and B) as well as the two P-channel MOSFETs (PA and PB) to shut off. When the internal die temperature cools to below 140°C, the amplifiers turn on and the LTC4413-1/LTC4413-2 reverts to normal operation. Note that prolonged operation under overtemperature conditions degrades reliability. Overvoltage Protection (LTC4413-2 Only) An overvoltage condition is detected whenever the overvoltage input (OVI) pin is pulled above 6V. The condition persists until the OVI voltage falls below 5.6V. The overvoltage protection (OVP) output is low unless an overvoltage condition is detected. If an overvoltage condition is present, the OVP output is pulled up to the voltage applied to the OVI input. This output signal can be used to enable or disable an external PFET that is placed between the input that is the source of the excessive voltage and the input to the LTC4413-2, thus eliminating the potential damage that may occur to the LTC4413-2 if its input voltage exceeds the absolute maximum voltage of 6V. See the Applications Information section Dual Battery Load Sharing with Automatic Switchover to a Wall Adapter with Overvoltage Protection for more information on using the overvoltage protection function within the LTC4413-2. Channel Selection and Status Output Two active-high control pins independently turn off the two ideal diodes contained within the LTC4413-1/LTC4413-2, controlling the operation mode as described by Table 1. When the selected channel is reverse biased, or the LTC4413-1/LTC4413-2 is put into low power standby, the status signal indicates this condition with a low voltage. Table 1: Mode Control ENB1 Low Low High High ENB2 Low High Low High STATE Diode’OR NB: The Two Outputs are not Connected Internal to the Device Diode A = ENABLED, Diode B = DISABLED Diode A = DISABLED, Diode B = ENABLED All Off (Low Power Standby) The function of the STAT pin depends on the mode that has been selected. Table 2 describes the STAT pin output current, as a function of the mode selected as well as the conduction state of the two diodes. Table 2: STAT Output Pin Function ENB1 Low ENB2 Low CONDITIONS Diode A Forward Bias, Diode B Forward Bias Diode A Forward Bias, Diode B Reverse Bias Diode A Reverse Bias, Diode B Forward Bias Diode A Reverse Bias, Diode B Reverse Bias Low High Diode A Forward Bias, Diode B Disabled Diode A Reverse Bias, Diode B Disabled High Low Diode A Disabled, Diode B Forward Bias Diode A Disabled, Diode B Reverse Bias High High Diode A Disabled, Diode B Disabled STAT ISNK = 0μA ISNK = 0μA ISNK = 11μA ISNK = 11μA ISNK = 0μA ISNK = 11μA ISNK = 0μA ISNK = 11μA ISNK = 11μA 441312fb 10 LTC4413-1/LTC4413-2 APPLICATIONS INFORMATION Introduction The LTC4413-1/LTC4413-2 are intended for power control applications that include low loss diode OR’ing, fully automatic switchover from a primary to an auxiliary source of power, microcontroller controlled switchover from a primary to an auxiliary source of power, load sharing between two or more batteries, charging of multiple batteries from a single charger and high side power switching. Dual Battery Load Sharing With Automatic Switchover to a Wall Adapter With Overvoltage Protection (LTC4413-2 Only) An application circuit for dual battery load sharing with automatic switchover of load from batteries to a wall adapter is shown in Figure 2. When the wall adapter is not present, whichever battery has the higher voltage provides the load current until it has discharged to the voltage of the other battery. The load is shared between the two batteries according to the capacity of each battery. The higher capacity battery provides proportionally higher current to the load. When a wall adapter input is applied, the output voltage rises as the body diode in MP2 conducts. When the output voltage is larger than the battery voltages, the LTC4413 turns off and very little load current is drawn from the batteries. At this time, the STAT pin pulls down MP1 MP2 IRLML6402 IRLML6402 WALL ADAPTER INPUT JACK the gate voltage of MP2, causing it to conduct. This status signal can be used to provide information as to whether the wall adapter (or BATB) is supplying the load current. If the wall adapter voltage exceeds the OVI trip threshold (VOVIH) then the wall adapter is disconnected via the external PFET, MP1. The OVI voltage can be monitored (through a voltage divider if necessary) to determine if an overvoltage condition is present. Capacitor C2 is required to dynamically pull up on the gate of PFET MP1 if a fast edge occurs at the wall adapter input during a hot plug. In the event that capacitor C2 (or the gate-to-source of MP1) is precharged below the OVI rising threshold. When a high voltage spike occurs, the OVP output cannot guarantee turning off MP1 before the load voltage exceeds the absolute maximum voltage for the LTC4413-2. This may occur in the event that the wall adapter suddenly steps from 5.5V to a much higher value. In this case, a zener diode is recommended to keep the output voltage to a safe level. Automatic PowerPath Control Figure 3 illustrates an application circuit for microcontroller monitoring and control of two power sources. The microcontroller’s analog inputs (perhaps with the aid of a resistor voltage divider) monitor each supply input and the LTC4413-1 status, and then commands the LTC4413-1 through the two ENBA/ENBB control inputs. RSTAT 470k C1 0.10μF R1 1Ω C2 10nF MICROCONTROLLER OPTIONAL 6.2V DFLZ6V2-7 TO LOAD BATA 1 INA 2 OUTA 10 + PRIMARY POWER SOURCE 1 INA CA 10μF RA 1Ω 2 3 4 IDEAL OUTA 10 9 STAT LOAD BATB IDEAL 9 STAT ENBA LTC4413-2 3 8 GND OVI 4 7 ENBB OVP OUTB 6 5 INB IDEAL COUT 4.7μF 10nF RSTAT 470k 441312 F02 STAT ENBA LTC4413-1 GND STAT OVP + C1: C1206C106K8PAC C2: C0403C103K8PAC COUT: C1206C475K8PAC AUXILIARY POWER SOURCE ENBB 5 INB CB 10μF RB 1Ω IDEAL OUTB 6 C1 4.7μF 441312 F03 Figure 2 Figure 3 441312fb 11 LTC4413-1/LTC4413-2 APPLICATIONS INFORMATION Automatic Switchover from a Battery to an Auxiliary Supply, or a Wall Adapter with Overvoltage Protection Figure 4 illustrates an application circuit where the LTC44132 is used to automatically switch over between a battery, an auxiliary power supply and a wall adapter. When the battery is supplying load current, OVP is at GND and STAT is high. If a higher supply is applied to AUX, the BAT will be disconnected from the load and the load is powered from AUX. When a wall adapter is applied, the body diode of MP2 forward biases. When the load voltage exceeds the AUX (or BAT) voltage, the LTC4413-2 senses this higher voltage and disconnects AUX (or BAT) from the load. At the same time it pulls the STAT voltage to GND, thereby turning on MP2. The load current is now supplied from the wall adapter. If the wall adapter voltage exceeds the OVI rising threshold, the OVP voltage rises and turns off MP1, disconnecting the wall adapter from the load. The output voltage collapses down to the AUX (or BAT) voltage and MP1 MP2 IRLML6402 IRLML6402 WALL ADAPTER INPUT JACK the LTC4413-2 reconnects the load to AUX (or BAT). Capacitor C2 is required to dynamically pull up on the gate of MP1 if a fast edge occurs at the wall adapter input during a hot plug. If the wall adapter voltage is precharged when an overvoltage spike occurs, the OVP voltage may not discharge capacitor C2 in time to protect the output. In this event, a zener diode is recommended to protect the output node until MP1 is turned off. Multiple Battery Charging Figure 5 illustrates an application circuit for automatic dual battery charging from a single charger. Whichever battery has the lower voltage will receive the larger charging current until both battery voltages are equal, then both are charged. While both batteries are charging simultaneously, the higher capacity battery gets proportionally higher current from the charger. For Li-Ion batteries, both batteries achieve the float voltage minus the forward regulation voltage of 15mV. This concept can apply to more than two batteries. The STAT pin provides information as to when the battery at OUTA is being charged. For intelligent control, the ENBA/ENBB input pins can be used with a microcontroller as shown in Figure 3. Automatic Switchover from a Battery to a Wall C1 0.10μF R1 1Ω C2 10nF 1 INA OUTA 10 IDEAL 8 OPTIONAL 6.2V DFLZ6V2-7 TO LOAD + BAT 3 4 GND OVI LTC4413-2 7 ENBB OVP 9 STAT OUTB 6 IDEAL ENBA COUT 4.7μF 441312 F04 BATTERY CHARGER INPUT 1 INA 2 IDEAL OUTA 10 VCC 470k STAT IS HIGH WHEN BAT1 IS CHARGING + LOAD BAT1 OVP 10nF RSTAT 560k STAT AUX 470k 470k 5 INB 2 ENBA LTC4413-1 3 9 STAT GND 4 ENBB OUTB 6 5 INB IDEAL C1: C1206C106K8PAC C2: C0403C103K8PAC COUT: C1206C475K8PAC + BAT2 441312 F05 LOAD Figure 4 Figure 5 441312fb 12 LTC4413-1/LTC4413-2 APPLICATIONS INFORMATION Adapter and Charger with Overvoltage Protection Figure 6 illustrates the LTC4413-2 performing the function of automatically switching a load over from a battery to a wall adapter while controlling an LTC4059 battery charger. When no wall adapter is present, the LTC4413-2 connects the load at OUTA from the Li-Ion battery at INA. In this condition, the STAT voltage is high, thereby disabling the battery charger. If a wall adapter of a higher voltage than the battery is connected to MP1 (but below the OVI threshold), the load voltage rises as the second ideal diode conducts. As soon as the OUTA voltage exceeds the INA voltage, the BAT is disconnected from the load and the STAT voltage falls, turning on the LTC4059 battery charger and beginning a charge cycle. If a high voltage wall adapter is inadvertently attached above the OVI rising threshold, the OVP pin voltage rises, disconnecting both the LTC4413-2 and the LTC4059 from potentially hazardous voltages. When this occurs, the load voltage collapses until it is below the BAT voltage causing the STAT voltage to rise, disabling the battery charger. At the same time, the LTC4413-2 automatically reconnects the battery to the load. One major benefit of this circuit is that when a wall adapter is present, the user may remove the battery and replace it without disrupting the load. Capacitor C2 is required to dynamically pull up on the gate of MP1 if a fast edge occurs at the wall adapter input during a hot plug. If the wall adapter voltage is precharged when an overvoltage spike occurs, the OVP voltage may not discharge capacitor C2 in time to protect the output. In this event, a zener diode is recommended to protect the output node until MP1 is turned off. Soft-Start Overvoltage Protection STAT STAT ENB BAT 1 INA 9 RSTAT 560k TO LOAD OUTA 10 LTC4059 VCC PROG MP1 IRLML6402 Li/CC GND WALL ADAPTER INPUT JACK C1 10μF Li-Ion 100k + IDEAL ENBA LTC4413-2 4 ENBB 3 GND OUTB 6 5 INB 2 IDEAL OVP COUT 4.7μF 1μF D1 OPTIONAL DFLZ6V2-7 C2 10nF OVI 441312 F06 Figure 6 441312fb 13 LTC4413-1/LTC4413-2 APPLICATIONS INFORMATION In the event that a low power external PFET is used for the external overvoltage protection device, care must be taken to limit the power dissipation in the external PFET. The operation of this circuit is identical to the “Automatic Switchover from a Battery to a Wall Adapter” application shown on the first page of this data sheet. Here, however, the ideal diode from INA to INB is disabled by pulling up on ENBA whenever an overvoltage condition is detected. This channel is turned-off using a resistor connected to OVP along with a 5.6V zener diode, ensuring the absolute maximum voltage at ENBA is not exceeded during an overvoltage event. When the overvoltage condition ends, the OVP voltage drops slowly, depending on the gate charge of the external PFET. This causes the external PFET to linger in a high RDS(ON) region where it can dissipate a significant amount of heat depending on the load current. To avoid dissipating heat in the external PFET, this application delays turning on the ideal diode from INA to OUTA, until the gate voltage of the external PFET drops below VENBIL, where the external PFET should safely be out of the high RDS(ON) region. This soft-start scheme can be used on either channel of the LTC4413-2. FDR8508 WALL ADAPTER INPUT C2 10nF 0.1μF 1Ω RENBA 560k D2 5.6V STAT ENBA LTC4413-2 OVI GND ENBB INB IDEAL 441312 F07 INA C1 10μF D1 OPTIONAL IDEAL OUTA VCC RSTAT 470k STAT BAT OVP OUTB COUT 4.7μF OVP TO LOAD + C1: C0805C106K8PAC C2: C0403C103K8PAC COUT: C1206C475K8PAC STAT IS HIGH WHEN WALL ADAPTER IS SUPPLYING LOAD CURRENT OVP IS HIGH WHEN WALL ADAPTER VOLTAGE > 6V Figure 7 441312fb 14 LTC4413-1/LTC4413-2 PACKAGE DESCRIPTION DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) 0.675 ± 0.05 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 R = 0.115 TYP 6 0.38 ± 0.10 10 3.00 ± 0.10 (4 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 1.65 ± 0.10 (2 SIDES) (DD) 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 441312fb 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 LTC4413-1/LTC4413-2 TYPICAL APPLICATION Automatic Switchover from a Battery to a Wall Adapter with Soft-Start Overvoltage Protection FDR8508 WALL ADAPTER INPUT C2 10nF 0.1μF 1Ω RENBA 560k D2 5.6V ENBA STAT LTC4413-2 OVI GND ENBB INB IDEAL 441312 F07 INA C1 10μF D1 OPTIONAL IDEAL OUTA VCC RSTAT 470k STAT BAT OVP OUTB COUT 4.7μF OVP TO LOAD + C1: C0805C106K8PAC C2: C0403C103K8PAC COUT: C1206C475K8PAC STAT IS HIGH WHEN WALL ADAPTER IS SUPPLYING LOAD CURRENT OVP IS HIGH WHEN WALL ADAPTER VOLTAGE > 6V RELATED PARTS PART NUMBER LTC1558/LTC1559 LTC1998 LTC4054 LTC4350 LTC4411 DESCRIPTION Backup Battery Controller with Programmable Output 2.5μA, 1% Accurate Programmable Battery Detector 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT Hot Swappable Load Share Controller 2.6A Low Loss Ideal Diode in ThinSOT COMMENTS Adjustable Backup Voltage from 1.2V NiCd Button Cell, Includes Boost Converter Adjustable Trip Voltage/Hysteresis, ThinSOTTM No External MOSFET, Sense Resistor or Blocking Diode Required, Charge Current Monitor for Gas Guaging, C/10 Charge Termination Allows N + 1 Redundant Supply, Equally Loads Multiple Power Supplies Connected in Parallel No External MOSFET, Automatic Switching Between DC sources, Simplified Load Sharing More Efficient than Diode OR’ing, Automatic Switching Between DC Sources, Simplified Load Sharing, 3V ≤ VIN ≤ 28V, 3V ≤ VIN ≤ 36V (HV) Drives Large QG PFETs, Very Low Loss Replacement for Power Supply O’Ring Diodes, 3.5V to 36V AC/DC Adapter Voltage Range, 8-Lead MSOP Package LTC4412/LTC4412HV PowerPath Controller in ThinSOT LTC4413 LTC4414 Dual 2.6A, 2.5V to 5.5V, Ideal Diodes in 3mm × 3mm DFN Lower Quiescent Current with Slower Response Time 36V, Low Loss PowerPath Controller for Large PFETs ThinSOT is a trademark of Linear Technology Corporation. 441312fb 16 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 0907 REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2006