LTC4413 Dual 2.6A, 2.5V to 5.5V, Ideal Diodes in 3mm × 3mm DFN U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO 2-Channel Ideal Diode ORing or Load Sharing Low Loss Replacement for ORing Diodes Low Forward ON Resistance (100mΩ Max at 3.6V) Low Reverse Leakage Current (1µA Max) Small Regulated Forward Voltage (28mV Typ) 2.5V to 5.5V Operating Range 2.6A Maximum Forward Current Internal Current Limit and Thermal Protection Slow Turn-Off to Protect Against Inductive Source Impedance-Induced Voltage Spiking Low Quiescent Current Status Output to Indicate if Selected Channel is Conducting Programmable Channel ON/OFF Low Profile (0.75mm) 10-Lead 3mm × 3mm DFN Package U APPLICATIO S ■ ■ ■ ■ ■ Battery and Wall Adapter Diode ORing in Handheld Products Backup Battery Diode ORing Power Switching USB Peripherals Uninterruptable Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LTC®4413 contains two monolithic ideal diodes, each capable of supplying up to 2.6A from input voltages between 2.5V and 5.5V. Each ideal diode uses a 100mΩ P-channel MOSFET that independently connects INA to OUTA and INB to OUTB. During normal forward operation the voltage drop across each of these diodes is regulated to as low as 28mV. Quiescent current is less than 40µA for diode currents up to 1A. If either of the output voltages exceeds its respective input voltages, that MOSFET is turned off and less than 1µA of reverse current will flow 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. Two active-high control pins independently turn off the two ideal diodes contained within the LTC4413, controlling the operation mode as described by Table 3. When the selected channel is reverse biased, or the LTC4413 is put into low power standby, a status signal indicates this condition with a low voltage. A 9µA open-drain STAT pin is used to indicate conduction status. When terminated to a positive supply through a 470k resistor, the STAT pin can be used to indicate that the selected diode is conducting with a HIGH voltage. This signal can also be used to drive an auxiliary P-channel MOSFET power switch to control a third alternate power source when the LTC4413 is not conducting forward current. The LTC4413 is housed in a 10-lead DFN package. U TYPICAL APPLICATIO LTC4413 vs 1N5817 Schottky 2000 VCC ENBA WALL ADAPTER (0V TO 5.5V) 470k LTC4413 ENBB STAT INB OUTB STAT IS HIGH WHEN BAT IS SUPPLYING LOAD CURRENT 1500 LTC4413 IOUT (mA) GND 1000 10µF 1N5817 CONTROL CIRCUIT INA BAT 500 OUTA TO LOAD 4.7µF 4413 TA01 0 0 100 200 VFWD (mV) 300 400 4413 TA01b 4413f 1 LTC4413 W U U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) INA, INB, OUTA, OUTB, STAT, ENBA, ENBB Voltage ................................... –0.3V to 6V Operating Temperature Range ................ – 40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C Continuous Power Dissipation (Derate 25mW/°C Above 70°C) ....................... 1500mW ORDER PART NUMBER TOP VIEW 10 OUTA INA 1 ENBA 2 GND 3 ENBB 4 7 NC INB 5 6 OUTB LTC4413EDD 9 STAT 11 8 NC DD PART MARKING DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN LBGN TJMAX = 125°C, θJA = 40°C/W (4-LAYER PCB) EXPOSED PAD (PIN 11) IS GND MUST BE SOLDERED TO PCB Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 6) SYMBOL PARAMETER CONDITIONS MIN VIN, VOUT Operating Supply Range for Channel A or B VIN and/or VOUT Must be in This Range for Proper Operation ● UVLO UVLO Turn-On Rising Threshold Max (VINA, VINB, VOUTA, VOUTB) ● UVLO Turn-Off Falling Threshold Max (VINA, VINB, VOUTA, VOUTB) ● TYP MAX UNITS 5.5 V 2.4 V 25 30 µA 0.5 2 µA 22 30 µA 2.5 1.7 V IQF Quiescent Current in Forward Regulation (Note 3) VINA = 3.6V, IOUTA = –100mA, VINB = 0V, IOUTB = 0mA ● ILEAK Current Drawn from or Sourced into IN when VOUT is Greater than VIN VIN = 3.6V, VOUT = 5.5V (Note 6) ● IQRGND Quiescent Current While in Reverse Turn-Off, Measured via GND VINA, VINB, VOUTB < VOUTA = 5.5V, VSTAT = 0V IQROUTA Quiescent Current While in Reverse Turn-Off, Current Drawn from VOUTA when OUTA Supplies Chip Power VINA, VINB, VOUTB < VOUTA = 5.5V ● 17 23 µA IQROUTB Quiescent Current While in Reverse Turn-Off, Current Drawn from VOUTA when OUTB Supplies Chip Power VINA, VINB, VOUTA < VOUTB = 5.5V ● 2 3 µA IQOFF Quiescent Current with Both ENBA and ENBB High VINA = VINB = 3.6V, VENBA and VENBB High, VSTAT = 0V ● 20 27 µA VRTO Reverse Turn-Off Voltage (VOUT – VIN) VIN = 3.6V 10 mV VFWD Forward Voltage Drop (VIN – VOUT) at IOUT = –1mA VIN = 3.6V 38 mV RFWD On Resistance, RFWD Regulation (Measured as ∆V/∆I) VIN = 3.6V, IOUT = –100mA VIN = 3.6V, IOUT = –500mA (Note 5) 140 100 mΩ mΩ RON On Resistance, RON Regulation (Measured as V/I at IIN = 1A) VIN = 3.6V, IOUT = –1.5A (Note 5) 200 mΩ tOFF PowerPathTM Turn-Off Time VIN = 3.6V, IOUT = –100mA –1 –5 ● 28 140 4 µs PowerPath is a trademark of Linear Technology Corporation. 4413f 2 LTC4413 ELECTRICAL CHARACTERISTICS The ● indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 6) SYMBOL PARAMETER CONDITIONS MIN 1.8 TYP MAX UNITS Short-Circuit Response IOC Current Limit VINX = 3.6V (Notes 4, 5) IQOC Quiescent Current While in Overcurrent Operation VINX = 3.6V, IOUT = 1.9A (Notes 4, 5) A 150 300 µA STAT Output ● ISOFF STAT Off Current Shutdown ISON STAT Sink Current VIN > VOUT, VCTL < VIL, IOUT < IMAX –1 0 1 µA 7 9 13 µA tS(ON) STAT Pin Turn-On Time 1 µs tS(OFF) STAT Pin Turn-Off Time 1 µs ENB Inputs VENB Rising ● ENB Inputs Falling Threshold Voltage VENB Falling ● ENB Inputs Hysteresis VENBHYST = (VENBIH – VENBIL) ENB Inputs Pull-Down Current VOUT < VIN = 3.6V, VENB > VENBIL VENBIH ENB Inputs Rising Threshold Voltage VENBIL VENBHYST IENB Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC4413 is guaranteed to meet performance specifications from 0°C to 70°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. ● 540 400 1.5 600 mV 460 mV 90 mV 3 4.5 µA 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: This 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. 4413f 3 LTC4413 U W TYPICAL PERFOR A CE CHARACTERISTICS IQF vs ILOAD IQF vs ILOAD 120°C 80°C 40°C 0°C –40°C 80 120°C 80°C 40°C 0°C –40°C 160 IQF (µA) 120 80 IQF AT 1A 60 120 IQF (µA) 160 IQF (µA) IQF vs Temperature 200 200 40 80 IQF AT 100mA 20 40 40 0 100E-6 0 1E-3 10E-3 100E-3 ILOAD (A) 1E+0 0 10E+0 1 0.50 1.50 ILOAD (A) 2 2.50 0 –40 3 40 0 4413 G01 4413 G02 IOC vs Temperature (VIN = 3.5V) RFWD vs VIN at ILOAD = 500mA 2.20 120 2.15 120°C 100 UVLO TURN-ON 80°C 2.10 2.05 2.00 UVLO TURN-OFF 2 1.85 –40 120 0 40 VFWD (mV) AND RFWD (mΩ) 120 RFWD (mΩ) RFWD IOUT = 1A 100 80 RFWD IOUT = 500mA 60 40 VFWD and RFWD vs ILOAD 300 120°C 80°C 40°C 0°C –40°C 250 200 150 RFWD 100 0 140 4413 G07 120°C 80°C 40°C 0°C –40°C VFWD 250 200 VFWD RFWD 150 100 50 50 20 5.5 4413 G06 VFWD (mV) AND RFWD (mΩ) 140 RFWD IOUT = 100mA 4.5 VINA (V) VFWD and RFWD vs ILOAD 300 100 60 TEMPERATURE (°C) 3.5 4413 G05 RFWD vs Temperature (VIN = 3.5V) 20 2.5 TEMPERATURE (°C) 160 –20 0 120 80 4413 G04 0 –60 –40°C 20 1.90 40 80 TEMPERATURE (°C) 0°C 60 40 1.95 0 40°C 80 RFWD (mΩ) IOC (A) UVLO (V) 3 120 4413 G03 UVLO Thresholds vs Temperature 4 1 –40 80 TEMPERATURE (°C) 0 0 500 1000 1500 2000 IOUT (mA) 2500 3000 4413 G08 1 10 100 ILOAD (mA) 1000 10000 4413 G09 4413f 4 LTC4413 U W TYPICAL PERFOR A CE CHARACTERISTICS VFWD vs ILOAD (VIN = 3.5V) 300 120°C 80°C 40°C 0°C –40°C 250 200 ENB Turn-Off CH4 CH4 CH4 CH2 150 CH3 CH1 100 CH2 CH1 CH3 CH2 CH3 50 CH1 4413 G11 400µs/DIV 10 100 ILOAD (mA) 1000 10000 4413 G12 4413 G10 ENB Threshold vs Temperature ENB Hysteresis vs Temperature 120 550 VIH 100 ENB HYSTERESIS (mV) 500 ENB THRESHOLD (mV) 450 VIL 400 350 80 60 40 20 300 –40 0 80 40 TEMPERATURE (°C) 0 –40 120 0 40 80 TEMPERATURE (°C) – ILEAK vs Temperature at VREVERSE = 5.5V – ILEAK vs VREVERSE 10E-6 10E-6 1E-6 80°C 40°C 0°C –40°C 1E-6 100E-9 10E-9 1E-9 –40 120 4413 G14 4413 G13 –ILEAK (A) 1 20µs/DIV CH4 = IOUT (200mA/DIV) CH3 = VOUT (2V/DIV) CH2 = VSTAT (2V/DIV) CH1 = VENBA (500mV/DIV) CH4 = IOUT (500mA/DIV) CH3 = VOUT (2V/DIV) CH2 = VSTAT (2V/DIV) CH1 = VENBA (500mV/DIV) 0 –ILEAK (A) VFWD (mV) ENB Turn-On 100E-9 10E-9 1E-9 0 40 80 TEMPERATURE (°C) 120 4413 G15 0 1 2 3 VREVERSE (V) 4 5 4413 G16 4413f 5 LTC4413 U U U PI FU CTIO S INA (Pin 1): Primary Ideal Diode Anode and Positive Power Supply. Bypass INA with a ceramic capacitor of at least 1µF. 1Ω snub resistors in series with a capacitor and higher valued capacitances are recommended when large inductances are in series with this input. This pin can be grounded when not used. ENBA (Pin 2): Enable Low for Diode A. Weak (3µA) pulldown. Pull this pin high to shut down this power path. Tie to GND to enable. Refer to Table 1 for mode control functionality. This pin can be left floating, weak pull-down internal to the LTC4413. GND (Pins 3, 11): Power and Signal Ground for the IC. The Exposed Pad of the package, Pin 11, must be soldered to PCB ground to provide both electrical contact to ground and good thermal contact to the PCB. ENBB (Pin 4): Enable Low for Diode B. Weak (3µA) pulldown. Pull this pin high to shut down this power path. Tie to GND to enable. Refer to Table 1 for mode control functionality. This pin can be left floating, weak pull-down internal to the LTC4413. OUTB (Pin 6): Secondary Ideal Diode Cathode and Output. Bypass OUTB with a high (1mΩ min) ESR ceramic capacitor of at least 4.7µF. This pin must be left floating when not in use. NC (Pin 7): No Internal Connection. NC (Pin 8): No Internal Connection. STAT (Pin 9): Status Condition Indicator. Weak (9µA) pulldown current output. When terminated, STAT = High indicates diode conducting. 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. This pin can also be left floating or grounded. OUTA (Pin 10): Primary Ideal Diode Cathode and Output. Bypass OUTA with a high (1mΩ min) ESR ceramic capacitor of at least 4.7µF. This pin must be left floating when not in use. INB (Pin 5): Secondary Ideal Diode Anode and Positive Power Supply. Bypass INB with a ceramic capacitor of at least 1µF. 1Ω snub resistors in series with a capacitor and higher valued capacitances are recommended when large inductances are in series with this input. This pin can be grounded when not used. 4413f 6 LTC4413 W BLOCK DIAGRA 1 INA OUTA OVER CURRENT PA –+ UVLO – ENA AENA OVERTEMP ENB + OUTA (MAX) BENA OVERTEMP OUTB (MAX) STAT STB ENBA 2 – VOFF 9 VGATEA + – O.5V 10 9µA + ENA AENA A + – 3µA 3 5 GND INB OUTB OVER CURRENT 6 PB –+ – + ENBB 4 + VOFF ENB VGATEB + – O.5V – BENA B + – 3µA 4413 F01 Figure 1 4413f 7 LTC4413 U OPERATIO The LTC4413 is described with the aid of the Block Diagram (Figure 1). Operation begins when the power source at VINA or VINB rises above the undervoltage lockout (UVLO) voltage of 2.4V and either of the ENBA or ENBB control pins is low. If only the voltage at the VINA pin is present, the power source to the LTC4413 (VDD) will be supplied from the VINA pin. The amplifier (A) will pull a current proportional to the difference between VINA and VOUTA from the gate (VGATEA) of the internal PFET (PA), driving this gate voltage below VINA. This will turn on PA. As VOUTA is pulled up to a forward voltage drop (VFWD) of 20mV below VINA, the LTC4413 will regulate VGATEA to maintain the small forward voltage drop. The system is now in forward regulation and the load at VOUTA will be powered from the supply at VINA. As the load current varies, VGATEA will be controlled to maintain VFWD until the load current exceeds the transistor’s (PA) ability to deliver the current as VGATEA approaches GND. At this point the PFET will behave as a fixed resistor with resistance RON, whereby the forward voltage will increase slightly with increased load current. As the magnitude of IOUT increases further (such that ILOAD > IOC), the LTC4413 will fix 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 2, illustrating the LTC4413 forward voltage drop versus that of a Schottky diode. IOC CURRENT (A) SLOPE 1/RON IFWD If another supply is provided at VINB, the LTC4413 will likewise regulate the gate voltage on PB to maintain the output voltage VOUTB just below the input voltage VINB. If this alternate supply, VINB, exceeds the voltage at VINA, the LTC4413 will select 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 will sense the increased voltage at VOUTA and amplifier A will increase the voltage VGATEA, reducing the current through PA. When VOUTA is higher than VINA + VRTO, VGATEA will be pulled up to VDD, which will turn off PA. The internal power source for the LTC4413 (VDD) will then be diverted to source 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 is drawn from VINA to sense the potential at VINA. When the selected channel of the LTC4413 is in reverse turn-off mode or both channels are disabled, the STAT pin will sink 9µA 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 will have its gate voltage pulled to VDD at a controlled rate, limiting the turn-off time to avoid voltage spiking at the input when being driven by an inductive source impedance. A 3µA pull-down current on the ENB pins will ensure a low level at these inputs if left floating. Overcurrent and Short-Circuit Protection LTC4413 SCHOTTKY DIODE SLOPE 1/RFWD 0 0 FORWARD VOLTAGE (V) 4413 F02 Figure 2 During an overcurrent condition, the output voltage will droop as the load current exceeds the amount of current that the LTC4413 can supply. At the time when an overcurrent condition is first detected, the LTC4413 will take some time to detect this condition before reducing the current to IMAX. For short durations after the output is shorted, the current may exceed IMAX. The magnitude of this peak short-circuit current can be large, depending on the load current immediately before the short circuit 4413f 8 LTC4413 U OPERATIO occurs. During overcurrent operation, the power consumption of the LTC4413 will be large, and is likely to cause an overtemperature condition as the internal die temperature exceeds the thermal shutdown temperature. The function of the STAT pin depends on the mode that has been selected. The following table describes the STAT pin output current as a function of the mode selected, as well as the conduction state of the two diodes. Overtemperature Protection Table 2. STAT Output Pin Funtion 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 be shut off. When the internal die temperature cools to below 140°C, the amplifiers will turn on and revert to normal operation. Note that prolonged operation under overtemperature conditions will degrade reliability. ENB1 ENB2 CONDITIONS STAT Low Low Diode A Forward Bias, Diode B Forward Bias ISNK = 0µA Diode A Forward Bias, Diode B Reverse Bias ISNK = 0µA Diode A Reverse Bias, Diode B Forward Bias ISNK = 9µA Diode A Reverse Bias, Diode B Reverse Bias ISNK = 9µA Diode A Forward Bias, Diode B Disabled ISNK = 0µA Diode A Reverse Bias, Diode B Disabled ISNK = 9µA Diode A Disabled, Diode B Forward Bias ISNK = 0µA Diode A Disabled Diode B Reverse Bias ISNK = 9µA Diode A Disabled, Diode B Disabled ISNK = 9µA Low High Channel Selection and Status Output Two active-high control pins independently turn off the two ideal diodes contained within the LTC4413, controlling the operation mode as described by Table 1. When the selected channel is reverse biased, or the LTC4413 is put into low power standby, the status signal indicates this condition with a low voltage. High High Low High Table 1. Mode Control ENB1 ENB2 STATE Low Low Diode OR (NB: The Two Outputs are Not Connected Internal to the Device) Low High Diode A = Enabled, Diode B = Disabled High Low Diode A = Disabled, Diode B = Enabled High High All 0ff (Low Power Standby) U W U U APPLICATIO S I FOR ATIO Introduction The LTC4413 is intended for power control applications that include low loss diode ORing, 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 An application circuit for dual battery load sharing with automatic switchover of load from batteries to a wall adapter is shown in Figure 3. When the wall adapter is not present, whichever battery that has the higher voltage will provide the load current until it has discharged to the voltage of the other battery. The load will then be shared between the two batteries according to the capacity of each battery. The higher capacity battery will provide proportionally higher 4413f 9 LTC4413 U W U U APPLICATIO S I FOR ATIO MP1 FDR8508 WALL ADAPTER C1 10µF R1 1000k R2 200k microcontroller’s analog inputs (perhaps with the aid of a resistor voltage divider) monitors each supply input and the LTC4413 status, and then commands the LTC4413 through the two ENBA/ENBB control inputs. 2 4 ENBA ENBB STAT 9 Automatic Switchover from a Battery to an Auxiliary Supply or a Wall Adapter 3,11 GND LTC4413 IDEAL OUTA 10 1 INA BATA 1-CELL Li-Ion RSTAT 470k TO LOAD IDEAL 5 INB OUTB 6 BATB 1-CELL Li-Ion C2 4.7µF C1:C1206C106K8PAC C2:C1206C475K8PAC 4413 F03 Figure 3 current to the load. When a wall adapter input is applied, the voltage divider formed by R1 and R2 will disable the LTC4413, causing the STAT pin voltage to fall, turning on MP1. At this point the load will be powered by the wall adapter and both batteries may be removed without interrupting the load voltage. When the wall adapter is removed, the output voltage will droop until the voltage divider turns on the LTC4413, at which point the batteries will revert to providing load power. The status signal can also be used to provide information as to whether the wall adapter (or BATB) is supplying the load current. Automatic PowerPath Control Figure 4 illustrates an application circuit for microcontroller monitoring and control of two power sources. The RSTAT 470k Figure 5 illustrates an application for implementing the function of automatic switchover from a battery to either an auxiliary supply or to a wall adapter using the LTC4413. The LTC4413 automatically senses the presence of a wall adapter as the ENBB pin voltage is pulled higher than its rising turn-off threshold of 550mV through resistive divider (R4 and R5). This disables the AUX input from powering the load. If the AUX is not present when a wall adapter is attached (i.e., the BAT is supplying load current), as the wall adapter voltage rises, the body diode in MP1 will forward bias, pulling the output voltage above the BAT voltage. The LTC4413 will sense a reverse voltage of as little as 10mV and turn off the ideal diode between INA and OUTA. This will cause the STAT voltage to fall, turning on MP1. The load will then draw current from the wall adapter, and the battery will be disconnected from the load. If the AUX is not present when the wall adapter is removed, the load voltage will droop until the BAT voltage exceeds the load voltage. The LTC4413 will sense that the BAT voltage is greater, causing the STAT voltage to rise, disabling MP1; the BAT will then provide power to the load. MP1 FDR8508 WALL ADAPTER MICROCONTROLLER 2 4 STAT ENBA ENBB STAT AUX POWER GND LTC4413 IDEAL OUTA 10 1 INA CA 10µF BAT TO LOAD IDEAL 5 INB OUTB 6 C1 4.7µF CB 10µF 4413 F04 Figure 4 R2 1000k 4 R3 100k 9 3,11 PRIMARY POWER C1 10µF R1 1Ω AUX ADAPTER ENBB STAT LTC4413 9 IDEAL OUTA 10 1 INA RSTAT 470k 3,11 GND IDEAL 5 INB OUTB 6 R4 1000k 2 R5 500k C2 4.7µF ENBA TO LOAD 4413 F05 C1:C0805C106K8PAC C2:C1206C475K8PAC Figure 5 4413f 10 LTC4413 U W U U APPLICATIO S I FOR ATIO If the AUX is present when a wall adapter is applied, as the resistive divider to ENBB rises through the turn-off threshold, the STAT pin will fall and MP1 will conduct allowing the wall adapter to power the load. When the wall adapter is removed while the AUX supply is present, the load voltage will fall until the voltage divider at the ENBB pin falls through its turn-on threshold. Once this occurs, the LTC4413 will automatically connect the AUX supply to the load when the AUX voltage exceeds the output voltage, causing the STAT voltage to rise and disabling the external PFET. current until both battery voltages are equal, then both will be charged. While both batteries are charging simultaneously, the higher capacity battery will get proportionally higher current from the charger. For Li-Ion batteries, both batteries will achieve the float voltage minus the forward regulation voltage of 20mV. This concept can apply to more than two batteries. The STAT pin provides information as to when battery 1 is being charged. For intelligent control, the ENBA/ENBB pin inputs can be used with a microcontroller as shown in Figure 4. When an AUX supply is attached, the voltage divider at ENBA will disconnect the battery from the load, and the auxiliary supply will provide load current, unless a wall adapter is present as described earlier. If the auxiliary supply is removed, the battery may again power the load, depending on if a wall adapter is present. Automatic Switchover from a Battery to a Wall Adapter and Charger Figure 7 illustrates the LTC4413 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 connects the load at OUTA from the Li-Ion battery at INA. In this condition, the STAT voltage will be high, thereby disabling the battery charger. If a wall adapter of a higher voltage than the battery is connected to INB, the load voltage will rise as the second ideal diode conducts. As soon as the OUTA voltage exceeds INA voltage, the BAT will be disconnected from the load and the STAT voltage will fall, turning on the LTC4059 battery charger and beginning a charge cycle. If the wall adapter is removed, the voltage at INB will collapse until it is below the load voltage. When this occurs, the LTC4413 will automatically reconnect the battery to the load and the STAT voltage will rise, disabling the LTC4059 battery charger. 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. Multiple Battery Charging Figure 6 illustrates an application circuit for automatic dual battery charging from a single charger. Whichever battery has the lower voltage will receive the larger charging BATTERY CHARGER INPUT LTC4413 9 STAT IDEAL OUTA 10 1 INA STAT IS HIGH 470k WHEN BAT1 IS CHARGING LOAD1 IDEAL 5 INB OUTB 6 BAT1 2 BAT2 4 3,11 ENBA LOAD2 ENBB GND 4413 F06 Figure 6 LTC4413 9 STAT IDEAL OUTA 10 1 INA LTC4059 VCC BAT ENB PROG R2 100k 1-CELL Li-Ion C1: C0805C106K8PAC C2: C1206C475K8PAC 4 ENBA ENBB 3,11 GND IDEAL 5 INB OUTB 6 Li CC GND WALL ADAPTER 2 R1 560k C1 10µF TO LOAD C2 4.7µF 4413 F07 Figure 7 4413f 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. 11 LTC4413 U PACKAGE DESCRIPTIO DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) R = 0.115 TYP 6 0.38 ± 0.10 10 0.675 ±0.05 3.50 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 3.00 ±0.10 (4 SIDES) 1.65 ± 0.10 (2 SIDES) PIN 1 PACKAGE TOP MARK OUTLINE (SEE NOTE 5) (DD10) DFN 0403 5 0.200 REF 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) 1 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 2.38 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 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. ALL DIMENSIONS ARE IN MILLIMETERS 3. 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 4. EXPOSED PAD SHALL BE SOLDER PLATED 5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1558/LTC1559 Backup Battery Controller with Programmable Output Adjustable Backup Voltage from 1.2V NiCd Button Cell, Includes Boost Converter LTC1998 2.5µA, 1% Accurate Programmable Battery Detector Adjustable Trip Voltage/Hysteresis, ThinSOTTM LTC4054 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT No External MOSFET, Sense Resistor or Blocking Diode Required, Charge Current Monitor for Gas Gauging, C/10 Charge Termination LTC4055 USB Power Controller and Li-Ion Charger Automatic Switchover, Charges 1-Cell Li-Ion Batteries LTC4350 Hot Swappable Load Share Controller Allows N + 1 Redundant Supply, Equally Loads Multiple Power Supplies Connected in Parallel LTC4351 MOSFET Diode-OR Controller 1.2V to 18V Input, Internal Boost Regulator for Driving N-Channel MOSFET LTC4411 2.6A Low Loss Ideal Diode in ThinSOT Load Sharing No External MOSFET, Automatic Switching Between DC Sources, Simplified LTC4412/LTC4412HV PowerPath Controllers in ThinSOT More Efficient than Diode ORing, Automatic Switching Between DC Sources, Simplified Load Sharing, 3V ≤ VIN ≤ 28V (3V ≤ VIN ≤ 36V for HV) ThinSOT is a trademark of Linear Technology Corporation. 4413f 12 Linear Technology Corporation LT/TP 1104 1K • PRINTED IN THE USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2004