LTC3440(电源转换模块)

LTC3455 1 3455f APPLICATIO S U FEATURES TYPICAL APPLICATIO U DESCRIPTIO U LOAD CURRENT (mA) 60 EF FI CI EN CY (% ) 80 75 70 65 85 90 95 100 3455 TA01b VBAT = 3.6V SWITCHER 1 VOUT1 = 1.8V SWITCHER 2 VOUT2 = 3.3V 1 10 100 1000 The LTC®3455 is a complete power management solution for a variety of portable applications. The device contains two synchronous step-down DC/DC converters, a USB power controller, a full-featured Li-Ion battery charger, a Hot Swap output, a low-battery indicator, and numerous internal protection features. The LTC3455 provides a small, simple solution for obtaining power from three different power sources: a single-cell Li-Ion battery, a USB port, and a wall adapter. Current drawn from the USB bus is accurately limited under all conditions. Whenever a USB or a wall adapter is present, the battery charger is enabled and all internal power for the device is drawn from the appropriate external power source. All outputs are dis- charged to ground during shutdown to provide complete output disconnect. The device is available in a 4mm × 4mm 24-pin exposed-pad QFN package. n Handheld Computers n Digital Cameras n MP3 Players , LTC and LT are registered trademarks of Linear Technology Corporation. n Seamless Transition between Input Power Sources: Li-Ion Battery, USB, and 5V Wall Adapter n Accurate USB Current Limiting (500mA/100mA) n Two High Efficiency DC/DC Converters: Up to 96% n Thermal Regulation Maximizes Battery Charge Rate without Risk of Overheating* n Full-Featured Li-Ion Battery Charger n Hot Swap™ Output for SDIO and Memory Cards n Pin-Selectable Burst Mode® Operation n Output Disconnect: All Outputs Discharged to Ground During Shutdown n Available in a 4mm × 4mm × 0.8mm 24-Pin QFN Package Efficiency Hot Swap is a trademark of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. *U.S. Patent 6,522,118 11 10 13 14 1Ω 1µF 1µF 10µF 4.7µF WALL 5V 3.3V, HS 8 6 5 9 1Ω 4.7µF USB 5V 4 2 3 18 12 249k 4.7µH 80.6k 10pF 10µF 3.3V 0.5A 1 7 100k 4.7µH 80.6k 10pF 10µF 1.8V 0.4A 16 17 LBO 24 23 20 21 19 22 15 0.1µF 1k 806k 1M 1.8V VBAT 2.49M 1M 2.49k 1M 1.8V 25 3455 TA01a µC USB CONTROLLER SINGLE CELL Li-ION 3.3V TO 4.2V 1.24k 3.32k ON/OFF + WALLFB HSI HSO VMAX USB SUSPEND USBHP SW2 FB2 SW1 FB1 TIMER PROG AI AO VBAT ON GND CHRG PBSTAT RST MODE LTC3455 ON2 PWRON HSON Dual DC/DC Converter with USB Power Manager and Li-Ion Battery Charger LTC3455 2 3455f VBAT, VMAX, USB Voltages ...........................–0.3V to 6V SW1, SW2 Voltages ....................–0.3V to (VMAX+0.3V) TIMER Voltage .............................–0.3V to (VMAX+0.3V) PWRON, ON, ON2, HSON Voltages .............–0.3V to 6V PBSTAT, RST, CHRG, AO Voltages ..............–0.3V to 6V HSI, HSO Voltages .......................................–0.3V to 6V MODE, USBHP, SUSPEND Voltages ............–0.3V to 6V WALLFB, AI, PROG Voltages .......................–0.3V to 2V FB1, FB2 Voltages ........................................–0.3V to 2V Junction Temperature ........................................... 125°C Operating Temperature Range (Note 2) .. –40°C to 85°C Storage Temperature Range ................. –65°C to 125°C ORDER PART NUMBER UF PART MARKING TJMAX = 125°C, θJA = 36°C/W, θJC = 2.5°C/W EXPOSED PAD (PIN 25) IS GND MUST BE SOLDERED TO PCB Consult LTC Marketing for parts specified with wider operating temperature ranges. 3455 LTC3455EUF ABSOLUTE AXI U RATI GS W WW U PACKAGE/ORDER I FOR ATIO U UW (Note 1) ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VBAT = 3.6V, VMAX = 3.6V, VPWRON = 2V, VON is open, VON2 = 0V, VUSB = 0V, VWALLFB = 0V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Battery Undervoltage Lockout Voltage VBAT Rising 2.9 3.0 3.2 V Battery Undervoltage Lockout Hysteresis 450 mV VBAT Pin Quiescent Current (Note 3) Burst Mode, Battery Powered VON2 = VMODE = 1V, Not Switching 110 160 µA PWM Mode, Battery Powered VON2 = 1V, VMODE = 0V, Not Switching 500 800 µA USB Powered VUSB = 5V, Charger Off 10 20 µA Wall Powered VWALL = 1.5V, VMAX = 4.5V, Charger Off 10 20 µA Shutdown VPWRON = 0V, VMAX = 0V 2 4 µA ON Pin Threshold 0.8 1.0 V PWRON Pin Threshold 0.8 1.0 V ON2 Pin Threshold 0.8 1.0 V MODE Pin Threshold 0.8 1.0 V WALLFB Pin Threshold Voltage WALLFB Rising l 1.20 1.23 1.26 V WALLFB Pin Hysteresis 60 mV ON Pin Pullup Current VON = 1V 2.5 µA PWRON Pin Pulldown Current VPWRON = 1V 2.5 µA ON2 Pin Pulldown Current VON2 = 1V 2.5 µA MODE Pin Pullup Current VMODE = 1V 2.5 µA WALLFB Pin Input Bias Current VWALLFB = 1.35V l ±1 ±30 nA PBSTAT Pin Low Voltage VON = 0V, IPBSTAT = 100µA 0.02 0.10 V VON = 0V, IPBSTAT = 1mA 0.20 0.35 V RST Pin Low Voltage IRST = 100µA 0.02 0.10 V IRST = 1mA 0.20 0.35 V RST Pulse Duration After FB1 and FB2 in Regulation 200 ms 24 25 23 22 21 20 19 7 8 9 TOP VIEW UF PACKAGE 24-LEAD (4mm · 4mm) PLASTIC QFN 10 11 12 6 5 4 3 2 1 13 14 15 16 17 18FB1 PROG TIMER CHRG USBHP SUSPEND FB2 AO AI HSON HSO HSI ON PB ST AT PW RO N M OD E RS T ON 2 SW 1 US B V B AT V M AX W AL LF B SW 2 LTC3455 3 3455f ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VBAT = 3.6V, VMAX = 3.6V, VPWRON = 2V, VON is open, VON2 = 0V, VUSB = 0V, VWALLFB = 0V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Battery-VMAX PMOS VMAX PMOS Switch On-Resistance 0.15 Ω VMAX Switch Current Limit 2.5 4.0 A VMAX Switch Current Limit at Startup With VMAX Rising, VMAX = 3V, VBAT = 3.6V 0.4 0.9 A Gain Block AI Pin Threshold Voltage l 0.784 0.805 0.826 V AI Pin/FB2 Pin Voltage Difference VFB2 – VAI –8 0 8 mV AI Pin Input Bias Current VAI = 0.85V l ±1 ±25 nA AO Pin Sink Current VAI = 0.6V, VAO = 1.5V 1.0 1.8 2.5 mA AO Pin Voltage VAI = 0.6V, IAO = 1mA 0.8 1.2 V Switching Regulators FB1, FB2 Voltage l 0.784 0.805 0.826 V FB1, FB2 Voltage Line Regulation VMAX = 3V to 5V 0.01 %/V FB1, FB2 Voltage Burst Mode Hysteresis VMODE = 2V 8 mV FB1, FB2 Pin Input Bias Current VFB1 = VFB2 = 0.85V l ±1 ±25 nA Switching Frequency Both Switchers 1.2 1.5 1.8 MHz PMOS Switch On-Resistance Both Switchers 0.35 Ω NMOS Switch On-Resistance Both Switchers 0.45 Ω PMOS Switch Current Limit Switcher 1 450 600 850 mA Switcher 2 700 900 1200 mA USB Power Manager USB Undervoltage Lockout Voltage From Low to High 3.75 3.90 4.10 V USB Undervoltage Lockout Hysteresis 150 mV USB Minimum Voltage to Charge Battery 4.0 V USB PMOS Switch On-Resistance VUSB = 5V 0.5 Ω USB Current Limit VUSB = 5V, VUSBHP = 2V l 440 475 500 mA VUSB = 5V, VUSBHP = 0V l 60 80 100 mA USB Suspend Mode Bias Current VUSB = 5V, VSUSPEND = 2V 4 20 µA SUSPEND Pin Threshold 0.8 1.1 V USBHP Pin Threshold 0.8 1.1 V SUSPEND Pin Pulldown Current VSUSPEND = 0.5V 2.5 µA USBHP Pin Pulldown Current VUSBHP = 0.5V 2.5 µA Hot Swap Output Hot Swap PMOS Switch On-Resistance VHSI = 3.3V 0.9 Ω Hot Swap PMOS Switch Current Limit VHSI = 3.3V, VHSO = 2.5V 120 160 mA HSON Pin Threshold 0.8 1.1 V HSON Pin Pulldown Current 2.5 µA LTC3455 4 3455f ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VBAT = 3.6V, VMAX = 3.6V, VPWRON = 2V, VON is open, VON = 0V, VUSB = 0V, VWALLFB = 0V unless otherwise noted. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC3455 is guaranteed to meet specified performance from 0°C to 70°C and is designed, characterized and expected to meet these extended temperature limits, but is not tested at –40°C and 85°C Note 3: Quiescent current is pulled from the VBAT pin when neither USB or wall power is present, and from the VMAX pin when either USB or Wall power is present. PARAMETER CONDITIONS MIN TYP MAX UNITS Battery Charger Regulated Charger VBAT Voltage 0°C ≤ TA ≤ 85°C 4.158 4.200 4.242 V Charger Current Limit (USB Powered) RPROG=2.49kΩ, VUSBHP = 2V, VUSB = 5V, 0°C ≤ TA ≤ 85°C 400 470 mA RPROG=2.49kΩ, VUSBHP = 0V, VUSB = 5V, 0°C ≤ TA ≤ 85°C 50 90 mA Charger Current Limit (Wall Powered) RPROG=2.49kΩ, VMAX = 4.5V, 0°C ≤ TA ≤ 85°C 425 500 575 mA Recharge Battery Voltage Threshold VBAT(REGULATED) – VRECHARGE 150 mV Trickle Charge Trip Threshold Battery Voltage Rising 2.85 V Trickle Charge Trip Hysteresis 60 mV Trickle Charge Current RPROG=2.49kΩ, VBAT = 2V 65 mA PROG Pin Current Internal Pull-Up Current, No RPROG 2 µA PROG Pin Voltage RPROG =2.49kΩ 1.23 V CHRG Pin Output Low Voltage ICHRG = 5mA 0.75 V Timer Accuracy CTIMER = 0.1µF ±10 % Junction Temperature in 105 °C Constant Temperature Mode TYPICAL PERFOR A CE CHARACTERISTICS UW Burst Mode Quiescent Current PWM Mode Quiescent Current Shutdown Quiescent Current TEMPERATURE (°C) –50 QU IE SC EN T CU RR EN T (µ A) 120 100 80 60 40 20 0 25 75 3455 G01 –25 0 50 100 125 VBAT = 3.6V NOT SWITCHING BOTH SWITCHERS ENABLED ONLY SWITCHER 1 ENABLED TEMPERATURE (°C) –50 QU IE SC EN T CU RR EN T (µ A) 600 500 400 300 200 100 0 25 75 3455 G02 –25 0 50 100 125 BOTH SWITCHERS ENABLED ONLY SWITCHER 1 ENABLED VBAT = 3.6V NOT SWITCHING TEMPERATURE (°C) –50 QU IE SC EN T CU RR EN T (µ A) 5 4 3 2 1 0 25 75 3455 G03 –25 0 50 100 125 VBAT = 3.6V LTC3455 5 3455f TYPICAL PERFOR A CE CHARACTERISTICS UW Feedback Pins (FB1, FB2) and AI Pin Voltage Switching Regulator Oscillator Frequency Switching Regulator Current Limit USB Pin Current Limit VMAX Pin Current Limit HSO Pin Current Limit Battery Undervoltage Lockout USB Undervoltage Lockout WALLFB Trip Voltage TEMPERATURE (°C) –50 US B PI N CU RR EN T (m A) 500 400 300 200 100 0 25 75 3455 G07 –25 0 50 100 125 USBHP = 2V USBHP = 0V VUSB = 5V TEMPERATURE (°C) –50 HS O PI N CU RR EN T LI M IT (m A) 200 150 100 50 0 25 75 3455 G09 –25 0 50 100 125 VHSI = 3.3V VHSO = 2.5V TEMPERATURE (°C) –50 SW IT CH IN G FR EQ UE NC Y (M Hz ) 2.0 1.5 1.0 0.5 0 25 75 3455 G05 –25 0 50 100 125 FOR BOTH SWITCHERS TEMPERATURE (°C) –50 CU RR EN T LI M IT (m A) 1000 800 600 400 200 0 25 75 3455 G06 –25 0 50 100 125 SWITCHER 1 SWITCHER 2 TEMPERATURE (°C) –50 VO LT AG E (m V) 815 810 805 800 795 790 785 25 75 3455 G04 –25 0 50 100 125 FB1 AI FB2 TEMPERATURE (°C) –50 V M AX C UR RE NT L IM IT (A ) 5.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 25 75 3455 G08 –25 0 50 100 125 STARTUP NORMAL OPERATION TEMPERATURE (°C) –50 BA TT ER Y UV LO (V ) 4.00 3.75 3.50 3.25 3.00 2.75 2.50 25 75 3455 G10 –25 0 50 100 125 FALLING RISING TEMPERATURE (°C) –50 US B UV LO (V ) 4.00 3.75 3.50 3.25 3.00 2.75 2.50 25 75 3455 G11 –25 0 50 100 125 FALLING RISING TEMPERATURE (°C) –50 W AL LF B TR IP V OL TA GE (V ) 1.26 1.24 1.22 1.20 1.18 1.16 1.14 1.12 1.10 25 75 3455 G12 –25 0 50 100 125 FALLING RISING LTC3455 6 3455f TYPICAL PERFOR A CE CHARACTERISTICS UW Battery Charger Regulation Voltage Battery Charger Recharge Threshold Battery Charger Trickle-Charge Threshold Charge Current When Wall-Powered Charge Current When USB-Powered PROG Pin Voltage vs Charge Current RDS(ON) for Switching Regulator Power Switches RDS(ON) for VMAX, USB, and HSO PMOS Switches TEMPERATURE (°C) –50 BA TT ER Y CU RR EN T (µ A) 15.0 10.0 5.0 12.5 7.5 2.5 0 25 75 3455 G18 –25 0 50 100 125 VBAT = 4.2V CHARGER OFF TEMPERATURE (°C) –50 R D S( ON ) 1.4 1.2 1.0 0.8 0.6 0.2 0.4 0 25 75 3455 G21 –25 0 50 100 125 HSO USB VMAX VHSI = 3.3V VUSB = 5V VBAT = 3.6V TEMPERATURE (°C) –50 R D S( ON ) 0.7 0.6 0.5 0.4 0.3 0.1 0.2 0 25 75 3455 G20 –25 0 50 100 125 NMOS PMOS VBAT = 3.6V TEMPERATURE (°C) –50 V B AT (V ) 4.30 4.25 4.20 4.15 4.10 4.05 4.00 25 75 3455 G13 –25 0 50 100 125 TEMPERATURE (°C) –50 V R EC HA RG E (V ) 4.30 4.25 4.20 4.15 4.10 4.05 4.00 25 75 3455 G14 –25 0 50 100 125 TEMPERATURE (°C) –50 TR IC KL E CH AR GE T HR ES HO LD (V ) 3.0 2.9 2.8 2.7 2.6 2.5 25 75 3455 G15 –25 0 50 100 125 FALLING RISING TEMPERATURE (°C) –50 BA TT ER Y CH AR GE C UR RE NT (m A) 600 500 400 300 200 100 0 25 75 3455 G16 –25 0 50 100 125 VBAT = 3.6V VMAX = 4.5V RPROG = 2.49k THERMAL CONTROL LOOP IN OPERATION TEMPERATURE (°C) –50 BA TT ER Y CH AR GE C UR RE NT (m A) 600 500 400 300 200 100 0 25 75 3455 G17 –25 0 50 100 125 VBAT = 3.6V VUSB = 5V RPROG = 2.49k VUSBHP = 2V VUSBHP = 0V THERMAL CONTROL LOOP IN OPERATION CHARGE CURRENT (mA) 0 V P RO G (V ) 1.50 1.25 1.00 0.75 0.50 0.25 0 300 3455 G19 100 200 400 500 VBAT = 3.6V VMAX = 4.5V RPROG = 2.49 TA = 25°C Battery Current When USB- or Wall-Powered LTC3455 7 3455f PI FU CTIO S UUU FB1 (Pin 1): Feedback Pin for Switcher 1. Set the output voltage by connecting feedback resistors to this pin. PROG (Pin 2): Charge Current Program and Charge Cur- rent Monitor Pin. Connect a resistor, RPROG, from this pin to ground to program battery charge current. IBAT = 1000 • 1.23V / RPROG In all modes the voltage on the PROG pin can be used to measure charge current. PROG has a weak pull-up current source to turn the charger off if the pin is left open. TIMER (Pin 3): Timer Capacitor Pin. Connect a capacitor, CTIMER, between this pin and ground to set the charge cycle termination time. The timer starts when USB or wall power is first present. The timer period is: TTIMER (hours) = CTIMER • (3 hours) / (0.1µF) Tie TIMER to ground to disable just the internal timer function. Tie TIMER to VMAX to use the charger in a constant-current-only mode (which disables the timer, voltage amplifier and trickle charge function). CHRG (Pin 4): Open-Drain Charge Status Pin. This pin is pulled low with an internal N-channel MOSFET whenever the battery charger is enabled, and is forced into a high impedance state whenever it is disabled. USBHP (Pin 5): USB High Power Mode Pin. This pin is used to select the appropriate USB current limit (either 500mA or 100mA). Pull high to select 500mA (high power mode); low to select 100mA (low power mode). SUSPEND (Pin 6): USB Suspend Pin. When this pin is pulled high, the internal USB power controller is disabled and the USB pin current reduces to less than 20µA. SW1 (Pin 7): Switch Pin for Switcher 1. Minimize the length of the metal trace connected to this pin. Place the inductor for Switcher 1 as close to this pin as possible. USB (Pin 8): USB Supply Pin. Input current into this pin is limited to either 100mA or 500mA based on the state of the USBHP pin. The charger and Switcher 1 will remain alive whenever USB power is present (when USB pin is above 3.9V and SUSPEND is low). VBAT (Pin 9): Battery Input Pin. Bypass this pin with a capacitor as close to the device as possible. VMAX (Pin 10): Max Voltage Pin. This pin is used to power the two internal step-down DC/DC converters and is provided externally to power other devices (i.e. LDOs or Switchers for LCD bias, white LED backlight drive, etc). When the LTC3455 is on and neither USB or wall power are available, an internal PMOS switch connects this pin to the VBAT pin. When either USB or wall power is present, they provide power to this pin, and the battery charger draws power from this pin. In shutdown, this pin is discharged to ground to provide output disconnect. WALLFB (Pin 11): Wall Power Detection Pin. This pin is the input to a comparator used to signal the presence of a 5V wall adapter. A resistor divider taken from the wall adapter input is connected to this pin to tell the LTC3455 when the adapter voltage is high enough to provide power to the LTC3455. When this pin is higher than 1.23V, the battery charger is enabled. The 5V wall adapter is con- nected to the VMAX pin through a Schottky diode. Tie WALLFB to ground if a wall adapter is not used. SW2 (Pin 12): Switch Pin for Switcher 2. Minimize the length of the metal trace connected to this pin. Place the inductor for Switcher 2 as close to this pin as possible. HSI (Pin 13): Hot Swap Input Pin. This pin is connected to the HSO pin through a current-limited PMOS switch. HSO (Pin 14): Hot Swap Output Pin. This output is used for memory cards or other devices that would appear as a short if they were hot-plugged directly to one of the outputs (typically the 3.3V output). The current out of this pin is limited to 160mA. HSON (Pin 15): Hot Swap Enable Pin. This pin turns on the PMOS that connects the HSI and HSO pins. AI (Pin 16): Gain Block Input Pin. This pin is the inverting input to an amplifier that can be used as a low-battery detector or as an LDO with the addition of an external PNP or PMOS. The non-inverting input of the gain block is connected to the 0.8V internal reference. AO (Pin 17): Gain Block Output Pin. This pin is an open- drain output, and is pulled low when the AI pin is less than 800mV. This output can be used as a low-battery detector, or as an LDO with the addition of an external PNP or PMOS. This pin can sink up to 1mA. LTC3455 8 3455f with the ON and PTSTAT pins, and a momentary-on switch. Tie PWRON to ground if not used. PBSTAT (Pin 23): Push-Button Status Pin. This pin is an open drain output that indicates the state of the ON pin (which is usually connected to a momentary-on push- button) to the microcontroller. This pin follows the state of the ON pin (PBSTAT goes low when ON is pulled low). ON (Pin 24): ON Pin. Pull this pin to ground to turn on the LTC3455. This pin is typically used with a momentary-on push-button switch to turn on the LTC3455. This pin would be held low until the PWRON pin is pulled high by a microcontroller to keep the LTC3455 turned on. If a momentary-on switch is not used, this pin can be held to ground to keep on the LTC3455. Leave ON open if not used. This pin has a weak pull-up current source. GND (Pin 25 – Exposed Pad): Ground Pin. The exposed backside pad is the only ground pin for the LTC3455 and must be soldered to the PC board ground plane for the device to operate properly. PI FU CTIO S UUU FB2 (Pin 18): Feedback Pin for Switcher 2. Set the output voltage by connecting feedback resistors to this pin. ON2 (Pin 19): Enable Pin for Switcher 2. This pin turns on Switcher 2 only if ON is low or PWRON is high. Switcher 2 cannot be turned on by itself. RST (Pin 20): Reset Pin. This pin is an open-drain output that provides a 200ms reset signal during power-up to initialize a microcontroller. MODE (Pin 21): Burst Mode Enable Pin. Tie this pin high to allow Burst Mode operation for the LTC3455. Burst Mode operation will provide superior efficiency when both outputs are operating with very low output currents. Tie this pin to ground to force PWM operation under all load current conditions. Burst Mode is disabled initially at startup (for 200ms) and also whenever external power is available (even if MODE is pulled high). PWRON (Pin 22): Power-On Pin. Pull this pin high to turn on the LTC3455. This pin is typically used in conjunction VMAX IS CONNECTED TO THE BEST AVAILABLE INPUT POWER SOURCE (WALL ADAPTER, USB OR BATTERY) USB POWER MANAGER BATTERY PMOS SWITCH BATTERY CHARGER GAIN BLOCK SWITCHER 1 SWITCHER 2 HOT SWAP VMAX USE TO POWER OTHER DC/DCs AND LDOs 5V WALL ADAPTER VOUT1 1.8V TYPICAL VOUT2 3.3V TYPICAL HOT SWAP OUTPUT 3.3V TYPICAL USB POWER 3.9V TO 5.3V Li-Ion BATTERY 3.3V TO 4.2V USE FOR LDO OR LOW BATTERY INDICATOR 3455 SBD SI PLIFIED W BLOCK DIAGRA W LTC3455 9 3455f BLOCK DIAGRA W 1.23V 3.9V + – – + 11 10 13 14