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Freescale Semiconductor Advance Information
Document Number: MC34676 Rev. 1.0, 10/2008
Dual 28 V Input Voltage Charger with Linear Regulator
The 34676 is a dual 28 V input voltage and fully-integrated single cell Li-Ion battery charger, targeting smart handheld applications. One of the inputs is optimized for charging with a USB port, and the second is optimized for an AC/DC adapter power source. The charger has two 28 V power devices, to eliminate the need of any external power source selection and input over-voltage protection circuitry. Each of the power devices independently controls the charge current from the input, and performs as an independent charger. Only one of the two chargers operate at a time. The AC charger current and the USB charger current are programmable, up to 1.2 A and 400 mA, with an external resistor respectively. The voltage across the two external resistors is also used to monitor the actual charge current through each charger respectively. The EOC current of both chargers is the same, and programmable by an external resistor. The 4.85 V regulator can be used to power a subsystem directly. The 34676 has a 5% constant current accuracy for the AC Charger over -40 to 85oC, and a 1.0% constant voltage accuracy over -40 to 85oC. A charge current thermal foldback feature, limits the charge current when the IC internal temperature rises to a preset threshold. Features * 1.0% voltage accuracy over -45 to 85C * No external MOSFET, reverse blocking diode, or current sense resistor are required * Additional voltage regulated output powered by USB input * Battery detection input * Charge current monitor with thermal limits * Integrated input over-voltage protection * Pb-free packaging designated by suffix code EP
34676
BATTERY CHARGER
EP SUFFIX (PB-FREE) 98ASA10814D 12-PIN DFN
ORDERING INFORMATION
Device MC34676BEP/R2 Temperature Range (TA) -40C to 85C Package 12-UDFN
Applications * * * * * Cell Phone Smart Phone PDA, PMP, PND, Handheld Portable Devices Portable Medical Devices
34676B
AC C1 C2 USB GND BAT BATDET USBOUT
C3
C4
IMIN IUSB RIMIN ISET
PPR USBEN CHG
VDDIO
MCU RIUSB RISET AC USB
Figure 1. 34676B Simplified Application Diagram
* This document contains certain information on a new product. Specifications and information herein are subject to change without notice.
(c) Freescale Semiconductor, Inc., 2008. All rights reserved.
INTERNAL BLOCK DIAGRAM
INTERNAL BLOCK DIAGRAM
USBOUT
AC BAT
USB
VUSB Mon
VAC Mon
Analog Control
VAC VBAT VOS
VBAT VUSB VOS
VREF
Temp Sense VBAT VTKL
TKL
PPR
RCH
VBAT VRCH VEOC IBAT/K
Logic
CHG
EOC
1.75 V OSC IBATDET
USBEN
BATDET
IMIN
ISET IUSB
GND
Figure 2. 34676 Simplified Internal Block Diagram
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PIN CONNECTIONS
PIN CONNECTIONS
Transparent Top View
AC USB PPR CHG USBEN IMIN
EPAD
BATDET BAT USBOUT ISET GND IUSB
Figure 3. 34676 Pin Connections Table 1. 34676 Pin Definitions A functional description of each pin can be found in the Functional Pin Description section beginning on page 14.
Pin Number 1 2 3 4 5 6 7 Pin Name AC USB PPR CHG USBEN IMIN IUSB Pin Function Input Input Output Output Input Output Output Formal Name AC Input Supply USB Input Supply Power Present Indicator Charge Status Indicator Charger Selection End-of-charge Current Setting USB Charger CCmode Current Setting and Charger Current Monitor Ground AC Charger CC-mode Current Setting and Charge Current Monitor Definition Power input from an AC/DC adapter. Power input from a USB port. Open-drain output to indicate the input power status. Open-drain output to indicate the charge status. Logic input. Low logic voltage selects the AC charger; high logic voltage selects the USB charger. End-of-charge (EOC) current setting. USB charger CC-mode current setting and charge current monitoring.
8 9
GND ISET
N/A Output
Ground. AC charger CC-mode current setting and charge current monitoring.
10 11 12 EPAD
USBOUT BAT BATDET EPAD
Output Output Input N/A
USB Regulator Output The USB input 4.85 V linear regulator with 45 mA current output capability. Charger Output Battery Detection Thermal Enhanced PAD Charger output. Connect this pin to the battery. Battery connection status detection. The exposed pad for thermal dissipation enhancement. Must be soldered on the large ground plane on the PCB to increase the thermal dissipation.
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ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 2. Maximum Ratings All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device.
Ratings ELECTRICAL RATINGS Input Supply Voltage Pins Charge State Indication Pins BAT, BATDET, USBEN, USBOUT, ISET, IUSB, IMIN Pins VAC, VUSB VPPR, VCHG VBAT, VBATDET, VUSBEN, VUSBOUT, VISET, VIUSB, VIMIN VESD 2000 200 -0.3 to 28 -0.3 to 12 -0.3 to 5.5 V V V Symbol Value Unit
ESD Voltage(1) Human Body Model (HBM) Machine Model (MM) THERMAL RATINGS Operating Ambient Temperature Range Storage Temperature Range Peak Package Reflow Temperature During Maximum Junction Temperature Thermal Resistance
(4)
V
TA TSTG Reflow(2), (3) TPPRT TJ RJC RJA
-40 to +85 -65 to +150 Note 3 +150
C C C C
Junction-to-Case Junction-to-Ambient
24 90
C/W
Notes 1. ESD testing is performed in accordance with the Human Body Model (HBM) (CZAP = 100 pF, RZAP = 1500 ), and the Machine Model (MM) (CZAP = 200 pF, RZAP = 0 ). 2. 3. Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause malfunction or permanent damage to the device. Freescale's Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow Temperature and Moisture Sensitivity Levels (MSL). Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics. Device mounted on the Freescale EVB test board per JEDEC DESD51-2.
4.
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ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics Characteristics noted under conditions VAC = VUSB = 5.0 V, -40C TA 85C, C1 = C2 = C4 = 1.0 F and C3 = 0.1 F (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25C under nominal conditions, unless otherwise noted.
Characteristic POWER-ON RESET (POR) AC POR Threshold Rising Falling USB POR Threshold Rising Falling INPUT-BAT OFFSET VOLTAGE (VOS) AC Input-BAT Offset Voltage Threshold Rising Falling USB Input-BAT Offset Voltage Threshold Rising Falling INPUT OVER-VOLTAGE PROTECTION (OVP) AC Input Over-voltage Threshold Rising Falling AC Input Over-voltage Rising Threshold Hysteresis USB Input Over Voltage Threshold Rising Falling USB Input Over-voltage Rising Threshold Hysteresis STANDBY CURRENT BAT Pin Sink Current Input not powered AC Pin Input Supply Current Charger disabled Charger enabled(5) USB Pin Input Supply Current Charger disabled Charger enabled(5) Notes 5. Supply current does not include the current delivered to the battery through the BAT pin. IUSBS 1.2 750 A mA IACS 1.2 750 A mA ISTDBY 1.0 A VOVPUSB 5.65 5.55 5.85 60 6.1 mV VOVPAC 6.6 6.3 6.8 200 7.0 mV V V VOSUSB 3.0 60 VOSAC 3.0 60 mV mV VPORUSB 3.0 2.8 3.9 VPORAC 3.0 2.8 3.9 V V Symbol Min Typ Max Unit
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ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics (continued) Characteristics noted under conditions VAC = VUSB = 5.0 V, -40C TA 85C, C1 = C2 = C4 = 1.0 F and C3 = 0.1 F (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25C under nominal conditions, unless otherwise noted.
Characteristic VOLTAGE REGULATION Regulated Output Voltage IBAT = 10 mA, TA = 25C IBAT = 10 mA, TA = -40 to 85C AC Charger Power MOSFET ON Resistance (VBAT = 4.0 V, IBAT = 500 mA, RISET = 3.75 k) USB Charger Power MOSFET ON Resistance (VBAT = 4.0 V, IBAT = 300 mA, IUSB is floating) CHARGE CURRENT AC Charger CC-mode Current Range AC Charger CC-mode Current Accuracy When set current between 300 mA to 1.2 A When set current between 100 to 300 mA(6) USB Charger CC-mode Current Range When IUSB is floating When IUSB is pulled down to ground with a resistor USB Charger CC-mode Current Accuracy AC Trickle Charge Current (% of programmed CC current) USB Trickle Charge Current (% of programmed CC current) End-of-Charge Threshold When RIMIN = 200 k When RIMIN = 25 k Current Slew Rate (On both rising and transitions) ISET Voltage for IAC Reference IUSB Voltage for IUSB Reference IMIN Voltage for IEOC Reference CHARGE THRESHOLD Recharge Voltage Threshold Recharge Voltage Threshold Hysteresis Trickle Charge Threshold Trickle Charge Threshold Hysteresis CHARGE CURRENT THERMAL FOLDBACK Current Foldback Die Temperature Limit Notes 6. Not tested but guaranteed by design. TLM 95 110 125 C VRECH VRECHHYS VTRK VTRKHYS 4.05 2.5 4.10 25 2.7 100 4.15 2.8 V mV V mV SR VISET VIUSB VIMIN ITRKLAC ITRKLUSB IEOC 5.5 60 20 10 80 1.0 1.0 0.5 12.3 98 120 mA/s V V V IUSB 100 85% 16% 16% 400 100% 20% 20% 400 115% 24% 24% IUSB IAC IUSB mA 95% 90% 100% 100% 105% 110% mA IAC 0.1 1.2 A IAC RDS(ON)AC RDS(ON)USB VBAT 4.184 4.158 4.20 4.20 4.216 4.242 500 1000 m m V Symbol Min Typ Max Unit
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ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics (continued) Characteristics noted under conditions VAC = VUSB = 5.0 V, -40C TA 85C, C1 = C2 = C4 = 1.0 F and C3 = 0.1 F (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25C under nominal conditions, unless otherwise noted.
Characteristic USBOUT REGULATOR Output Voltage VUSB=5.35 V, IUSBOUT=10 mA Dropout Voltage At 45 mA output current Output Current Limit Output Pull-down Resistance BATTERY DETECTION INPUT Internal Pull-up Current Comparator Falling Threshold Hysteresis LOGIC INPUT AND OUTPUT USBEN Input High USBEN Input Low USBEN Internal Pull-down Current Open-drain Output Low 10 mA sink current PPR and CHG Leakage Current When the Output is High-impedance VCHG = VPPR = 5.0 V 0.6 1.0 A VIH VIL 1.5 0.5 5.0 V V A V IBATDET VBATDET 2.0 1.65 4.0 1.75 200 6.0 1.85 A V mV 46 200 250 mA k VUSBOUT 4.63 4.85 5.0 mV V Symbol Min Typ Max Unit
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ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
Table 4. Dynamic Electrical Characteristics Characteristics noted under conditions VAC = VUSB = 5.0 V, -40C TA 85C, C1 = C2 = C4 = 1.0 F and C3 = 0.1 F (See Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VAC = VUSB = 5.0 V and TA = 25C under nominal conditions, unless otherwise noted.
Characteristic END-OF-CHARGE EOC Filtering Time OSCILLTOR Oscillation Frequency fOSC 42 50.0 54.5 kHz tEOC 500 1000 ms Symbol Min Typ Max Unit
ELECTRICAL PERFORMANCE CURVES
750 Charger Current (mA) 600 450 300 150 0 0 25 50 75
Charger Current Battery Voltage
5 Battery Voltage (V) 4 3 2 1
1.2 1.0 0.8 VISET (V) 0.6 0.4 0.2 0.0 4.0 4.5 5.0 5.5 6.0 6.5 7.0
0 100 125 150 175
Charge Time ( min)
Figure 4. AC Charger Complete Charge Cycle VAC=5.0 V, RISET=5.22 k, 740mAh Battery, TA=25oC
Input Voltage (V)
Figure 6. VISET vs VAC VBAT=3.7 V, RISET=5.22 k, TA=25oC
AC Pin Supply Current ( A)
3000 2500
Charger Enabled
1.0 0.8 VISET (V) 0.6 0.4 0.2
7
RISET=26.7k
RISET=5.22k
2000 1500 1000 500 0 3 4 5
Charger Disabled
6
0.0 0
150
300
450
600
750
Input Voltage (V)
Figure 5. AC Pin Supply Current vs VAC IBAT=0 mA, TA=25oC
Charger Current (mA)
Figure 7. VISET vs AC Charger Charge Current VAC=5.0 V, TA=25oC
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES
Constant Charge Current (mA)
750
RISET=5.22k
4.24 4.22 4.20 VBAT (V) 4.18 4.16 4.14 4.12
600 450 300 150 0 4.0
RISET=26.7k
4.5
5.0
5.5
6.0
6.5
7.0
4.10 -40
-20
0
20
40
o
60
80
Input Voltage (V)
Figure 8. AC Charger CC Current vs VAC VBAT=3.7 V, TA=25C
Temperature ( C)
Figure 11. VBAT vs TA VAC=5.0 V, IBAT=0 mA
750 Charge Current (mA) 600 450 300 150 0 0
RISET=5.22k RISET=26.7k
AC pin supply current ( A)
2000 1750 1500 1250 1000 750 500 250 0 -40 -20 0 20 40
o
Charger Enabled
Charger Disabled
1
2
3
4
5
60
80
Battery Voltage (V)
Figure 9. AC Charger Charge Current vs Battery Voltage VAC=5.0 V, TA=25C
Temperature ( C)
Figure 12. AC Pin Supply Current vs TA VAC=5.0 V, IBAT=0 mA
Trickle Charge Current (mA)
200 150 100 50
RISET=26.7k
1.10 1.05 VISET ( V)
RISET=5.22k
1.00 0.95 0.90 -40
0 4.0
4.5
5.0
5.5
6.0
6.5
7.0
-20
0
20
40
o
60
80
Input Voltage (V)
Figure 10. AC Charger Trickle Charge Current vs VAC VBAT=2.0 V, TA=25C
Temperature ( C)
Figure 13. VISET vs TA VAC=5.0 V, RISET=5.22 k, VBAT=3.7 V
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES
450
Charger Current (mA)
500 400 300 200
Charger Current Battery Voltage
5 Battery Voltage (V) 4 3 2 1 50 100 150 200 0
400 RDS(ON) ( m) 350 300 250 -40
100 0 0
-20
0
20
40
o
60
80
Temperature ( C)
Figure 14. AC Charger RDS(ON) vs TA VBAT=4.0 V, IAC=750 mA, IBAT=500 mA
Charge Time ( min)
Figure 17. USB Charger Complete Charge Cycle VUSB=5.0 V, RIUSB=6.52 k, 740 mA Battery, TA=25oC
Constant Charge Current ( mA)
750 600 450 300 150 0 -40 -20 0 20
RISET=5.22k
USB Pin Supply Current ( A)
900
3000 2500 2000 1500 1000 500 0 3
Charger Enabled Charger Disabled
RISET=26.7k
40
o
60
80
4
5
6
Temperature ( C)
Figure 15. AC Charger CC Current vs TA VAC=5.0 V, VBAT=3.7 V
Input Voltage (V)
Figure 18. USB Pin Supply Current vs VUSB IBAT=0 mA, TA=25oC
Trickle Charge Current ( mA)
250 200
VIUSB (V)
RISET=26.7k
1.2 1.0
RISET=5.22k
150 100 50 0 -40 -20 0 20 40
o
0.8 0.6 0.4 0.2 0.0 4.0 4.5 5.0 5.5 6.0
60
80
Temperature ( C)
Figure 16. AC Charger Trickle Charge Current vs TA VAC=5.0 V, VBAT=2.0 V
Input Voltage (V)
Figure 19. VIUSB vs VUSB VBAT=3.7 V, RIUSB=9.76 k, TA=25oC
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES
1.0 0.8 VIUSB (V) 0.6 0.4 0.2 0.0 0 50 100 150 200 250 300
RIUSB=9.76k
Trickle Charge Current (mA)
200 150 100 50 0 4.0
IUSB pin is floating RIUSB=9.76k
4.5
5.0
5.5
6.0
Charger Current (mA)
Figure 20. VIUSB vs USB Charger Charge Current VUSB=5.0 V, TA =25oC
Input Voltage (V)
Figure 23. USB Charger Trickle Charge Current vs VUSB VBAT=2.0 V, TA=25C
Constant Charge Current (mA)
5.00
400
IUSB pin is floating
4.95 VUSBOUT (V) 4.90 4.85 4.80 4.75
300 200 100 0 4.0 4.5 5.0 5.5 6.0
RIUSB=9.76k
4.70 0
10
20
30
40
50
Input Voltage (V)
Figure 21. USB Charger CC Current vs VUSB VBAT=3.7 V, TA=25C
IUSBOUT (mA)
Figure 24. VUSBOUT vs IUSBOUT VUSB=5.0 V, TA=25C
500 Charge Current (mA) 400 300 200 100 0 0 1 2 3 4 5
RIUSB=9.76k IUSB pin is floating
6.0 5.5 VUSBOUT (V) 5.0 4.5 4.0 3.5 3.0 3.0 3.5 4.0 4.5 5.0 VUSB (V) 5.5 6.0
Battery Voltage (V)
Figure 22. USB Charger Charge Current vs VBAT VUSB=5.0 V, TA=25C
Figure 25. VUSBOUT vs VUSB IUSBOUT=0 mA, TA=25oC
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES
4.24 4.22 RDS(ON) ( m) -20 0 20 40
o
900 850 800 750 700 650 600 550 60 80 500 -40 -20 0 20 40
o
4.20 VBAT (V) 4.18 4.16 4.14 4.12 4.10 -40
60
80
Temperature ( C)
Figure 26. VBAT vs TA VUSB=5.0 V, IBAT=0 mA
Temperature ( C)
Figure 29. USB Charger RDS(ON) vs TA VBAT=4.0 V, IUSB=400 mA, IBAT=300 mA
USB Pin Supply Current ( A)
2000 1750 1500 1250 1000 750 500 250 0 -40 -20 0 20 40
o
Constant Charge Current ( mA)
500 400 300 200 100 0 -40 -20 0 20 40
o
Charger Enabled
IUSB pin is floating
Charger Disabled
RIUSB=9.76k
60
80
60
80
Temperature ( C)
Figure 27. USB Pin Supply Current vs TA VUSB=5.0 V, IBAT=0 mA
Temperature ( C)
Figure 30. USB Charger CC Current vs TA VUSB=5.0 V, VBAT=3.7 V
1.0 VIUSB ( V) 0.9 0.8 0.7 0.6 0.5 -40 -20 0 20 40
o
Trickle Charge Current ( mA)
1.1
250 200 150 100 50 0 -40 -20 0 20 40
o
IUSB pin is floating RIUSB=9.76k
60
80
60
80
Temperature ( C)
Figure 28. VIUSB vs TA VUSB=5.0 V, RIUSB=9.76 k, VBAT=3.7 V
Temperature ( C)
Figure 31. USB Charger Trickle Current vs TA VUSB=5.0 V, VBAT=2.0 V
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES
4.84 4.82 VUSBOUT ( V) 4.80 4.78 4.76 -40
IUSBOUT=0mA IUSBOUT=50mA
Recharge Voltage Threshold ( V)
4.20 4.15 4.10 4.05 4.00 3.95 -40 -20 0 20 40
o
-20
0
20
40
o
60
80
60
80
Temperature ( C)
Figure 32. VUSBOUT vs TA VUSB=5.0 V
Temperature ( C)
Figure 34. Recharge Voltage Threshold vs TA VAC=5.0 V or VUSB=5.0 V
0.8 0.6 0.4 0.2 0.0 -40 -20 0 20 40
o
End-of-charge Current ( mA)
1.0 BAT Pin Current ( A)
120 100 80 60 40 20 -40 -20 0 20 40
o
RIMIN=25k
60
80
60
80
Temperature ( C)
Figure 33. BAT Pin Current vs TA VBAT=4.2 V, Input Not Powered or Charger Disabled
Temperature ( C)
Figure 35. End-of-charge Current vs TA VAC=5.0 V or VUSB=5.0 V
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FUNCTIONAL DESCRIPTION INTRODUCTION
FUNCTIONAL DESCRIPTION
INTRODUCTION
The 34676 is a dual 28 V input charger, with 4.85 V regulated voltage output optimized for smart handheld devices. Many smart handheld applications require frequent data exchange between the device and the personal computer via a USB port. It is convenient that the device charges the Li-Ion battery by taking advantage of the 500 mA output current from the USB port, while exchanging the data. In the meantime, the handheld device also needs to be able to charge at a faster rate, when using an AC/DC adapter with higher than 500 mA output current capability. Such applications require a charger that can select one of the two power sources, and charge at a user desired current rate. The 34676 is optimized for such applications. The 34676 requires only four external capacitors and three resistors to build a fully functional charger for space-limited applications, such as PDAs, cell phones, and digital still cameras. Its ultra high voltage accuracy (0.4%) and temperature limited charging current, offer additional battery safety during charging. Two external resistors, RIUSB and RISET, set the CC-mode current of the USB charger and the CC-mode current of the AC charger respectively. Both the USB charge current and the AC charge current can be monitored during the whole charge cycle, by measuring the voltage across RIUSB and RISET. For a deeply discharged battery with a voltage lower than 2.7 V, the charger preconditions the battery with 20% of the corresponding CC-mode current. The end-of-charge (EOC) current is set by an external resistor, RIMIN. The linear regulator provides 4.85 V with 45 mA (USBOUT) current capability. The output is turned on when the voltage of the USB input power supply is above the POR threshold but lower than the OVP threshold. The linear regulator is independent. It is not related to any signals of the charger including the enable input pin. Two indication outputs (PPR, CHG) make it easy to report the input power status and the charge status to MCUs or users via LEDs.
FUNCTIONAL PIN DESCRIPTION
AC INPUT SUPPLY (AC)
Power input from an AC/DC adapter. Bypass to ground with a 1.0 F capacitor.
END-OF-CHARGE CURRENT SETTING (IMIN)
The end-of-charge current is set by connecting a resistor, RIMIN, between this pin to ground. Both the AC charger and the USB charger have the same EOC current value.
USB INPUT SUPPLY (USB)
Power input from a USB port. Bypass to ground with a 1.0 F capacitor.
USB CHARGER CC-MODE CURRENT SETTING AND CHARGE CURRENT MONITOR (IUSB)
The CC-mode current of the USB charger is set by connecting a resistor, RIUSB, between this pin and ground. When the USB charger is charging in the constant-current mode, the voltage at this pin is 1.0 V. The voltage reduces proportionally as the charge current reduces in the constantvoltage mode. During the whole charge cycle, the voltage at this pin can be used to monitor the charge current using the following equation: V IUSB I BAT = --------------- I USB 1.0V equ.1
POWER PRESENT INDICATOR (PPR)
Open-drain output to indicate the input power status. When both the AC and the USB input voltages are under the power-on-reset threshold voltage, or above the over-voltage protection threshold voltage, the PPR outputs a highimpedance. In any other conditions, the PPR outputs a low voltage.
CHARGE STATUS INDICATOR (CHG)
Open-drain output to indicate the charge status. The output is low when the 34676 is charging until the EOC conditions are reached.
CHARGER SELECTION (USBEN)
Logic input. This pin selects the AC charger or the USB charger. When driven to low, the AC charger is selected. When driven to high, the USB charger is selected. This pin is internally pulled to ground by a weak current source. The input is equivalent to low when this pin is floating.
where IBAT is the actual charge current, VIUSB is the voltage at the IUSB pin and IUSB is the CC-mode current of the USB charger programmed by the RIUSB. When this pin is floating, the CC-mode current of the USB charger is set to a default value of 400 mA.
GROUND (GND)
Ground.
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FUNCTIONAL DESCRIPTION FUNCTIONAL PIN DESCRIPTION
AC CHARGER CC-MODE CURRENT SETTING AND CHARGE CURRENT MONITOR (ISET)
The CC-mode current of the AC charger is set by connecting a resistor, RISET, between this pin and ground. When the AC charger is charging in the constant-current mode, the voltage at this pin is 1.0 V. The voltage reduces proportionally as the charge current reduces in the constantvoltage mode. During the whole charge cycle, the voltage at this pin can be used to monitor the charge current using the following equation: V ISET I BAT = -------------- I AC 1.0V equ.2
the output current capability is 45 mA. The USB regulator is enabled when the USB input voltage is between the POR and the OVP thresholds. Bypass to ground with a 0.1 F or higher capacitor.
CHARGER OUTPUT (BAT)
Charger output pin. Connect this pin to the battery being charged. Bypass to ground with a 1.0F or higher capacitor.
BATTERY DETECTION (BATDET)
Battery detection input. This input has a threshold of 1.75 V. When the input voltage is lower than the threshold, the charger is enabled. An internal 4.0 A pull-up current source pulls the voltage higher than the threshold if this pin is floating.
where IBAT is the actual charge current, VISET is the voltage at the ISET pin and IAC is the CC-mode current of the AC charger programmed by the RISET.
EXPOSED PAD (EPAD)
The exposed pad needs to be connected to GND. It must be soldered on a large ground plane on the PCB to enhance the thermal dissipation.
USB REGULATOR OUTPUT (USBOUT)
The USB regulator output pin. The USB linear regulator is powered by the USB input. The output voltage is 4.85 V and
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FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
MC34676 - Functional Block Diagram
Integrated Supply Internal Supply & Reference
Sensing & Control VIN Monitor Current Setting Current Monitor Charge Control End of Charge VIN - BAT Comparator
Outputs
Power MOSFET
Die Temperature Feedback Battery Detection Logic Logic Control & Status Indication
Integrated Supply Sensing & Control Logic Outputs
Linear Regulator
Figure 36. 34676 Functional Internal Block Diagram
OUTPUTS POWER MOSFET
The power MOSFET function contains two power MOSFETs that pass the charging current from the inputs (AC or USB) to the output (BAT).
SENSING & CONTROL VIN MONITOR
The input voltage monitor block monitors the AC input and the USB input voltages. If any input voltage is lower than its POR or higher than its OVP threshold, this block outputs a logic signal to disable the corresponding charger.
LINEAR REGULATOR
The linear regulator outputs a regulated 4.85 V from the USB input voltage with 45 mA (USBOUT) current capabilities. The regulator is only controlled by the power supply input. It is not controlled by the enable input or any other input signals. When the USB power supply input is powered, the Input Voltage Monitor and the Internal Supply blocks detect that the input voltage is greater than the POR rising threshold, and lower than the OVP threshold, the regulator is enabled and outputs 4.85 V.
VIN - BAT COMPARATOR
The input and battery voltage comparator monitors the voltage difference between the input voltage and the battery voltage. The input voltage has to be higher than the battery voltage for the charger to be enabled. If the voltage of the AC input or the USB input falls below the battery voltage, this block outputs a signal to disable the corresponding charger to prevent the leakage current from the battery to the input.
INTEGRATED SUPPLY INTERNAL SUPPLY & REFERENCE
This block steps down the high input voltage to a lower voltage to power all the internal blocks.
CHARGE CONTROL
The charge control block controls the gate voltage of the power MOSFETs to regulate the charge current, the battery voltage, or the die temperature. It can also completely turn off the power MOSFETs to stop the current flow between the input and the battery.
DIE TEMPERATURE SENSE
The die temperature sense block monitors the die temperature. Once the die temperature reaches the
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FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION
threshold temperature, this block tries to reduce the charge current to prevent further die temperature rise.
BATTERY DETECTION
This block detects the connection status of the battery. It is also an enable input for the 34676.
CHARGE CURRENT SETTING AND CURRENT MONITOR
This block sets the CC-mode charge current and monitors the actual charge current of both the AC charger and the USB charger during the whole charge cycle.
LOGIC LOGIC CONTROL AND STATUS INDICATION
The logic control block determines the on and off of the charger, based on the signals from the Input Voltage Monitor block, the Internal Supply block, the Input and Battery Voltage Comparator block, the charger selection pin, and the external enable input pin.
END OF CHARGE (EOC) CURRENT SETTING
The EOC current setting block sets the EOC current of both the AC charger and the USB charger.
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FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
The 34676 uses the standard charge profile with trickle mode, constant-current (CC) mode, and constant-voltage (CV) mode, as shown in Figure 37. Both the CC-mode and the CV-mode are called fast charge mode. Figure 40 shows the complete charge cycle state diagram. When the input voltage rises above the internal power-onreset threshold and is less than its OVP threshold, the PPR pin outputs a logic low level to indicate the power supply presence. The charger starts to verify the enable input (BATDET input). If it is enabled, the charger will start with the trickle mode until the battery voltage is above 2.7 V. The CHG pin turns to logic low level at the beginning of the trickle mode. If the battery voltage is unable to rise due to a battery failure, the charging will remain in the trickle-charge mode. When the battery voltage reaches the 2.7 V threshold, the 34676 softly changes to the CC-mode. The soft transition minimizes the input voltage drop and reduces the requirement of the input decoupling capacitance. When the battery voltage reaches 4.2 V, the 34676 enters the CVmode and regulates the output voltage at 4.2 V. The charge
.
current decreases gradually in the CV-mode. When the current drops to the EOC current threshold, the 34676 outputs a logic high level at the CHG pin, to indicate that the charger has entered into the charge completion mode. After the charge is completed, the 34676 continues to regulate the output to 4.2 V. If a load is in parallel with the battery, the charger continues to output the current to the load even the charge is completed. When the battery voltage is below the recharge voltage threshold of 4.10 V, the 34676 returns to the fast charge mode and indicates a low signal at the CHG pin. When one of the following conditions happen, the chargers stop charging and enter disable mode. 1. VIN > VOVP 2. VIN -VBAT < VOS 3. The voltage at BATDET pin is higher than 1.75 V where VIN can be either the AC or the USB input voltage.
Trickle Constant Current
Constant Voltage
Charge Voltage
100mV
Charge Current
ITRKL IEOC
TIME
CHG
TIME
Figure 37. Typical Charge Cycle
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FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES
DETAILED FUNCTIONAL DEVICE OPERATION DC 28V INPUT
The 34676 consists of two power MOSFETs, as shown in Figure 38, that act as power source selection devices and pass the charge current from input to output. Both inputs are capable of withstanding up to 28 V DC input. The charger only charges when the input voltage is in a power-good range.
AC CHARGE CURRENT SETTING
An external reference resistor between the ISET pin and ground sets the CC-mode charge current of the AC charger by the following equation: 3950 equ.3 I AC = -------------R ISET where RISET is the resistance between the ISET pin and ground. In addition, the current out of the ISET pin is also proportional to the charge current. The system may measure the ISET pin voltage to monitor the actual charge current, as given in equ.2, during the whole charging cycle.
AC USB BAT
USB CHARGE CURRENT SETTING
An external reference resistor between the IUSB pin and ground sets the CC-mode charge current of the USB charger by the following equation: 1975 equ.4 I USB = --------------R IUSB where RIUSB is the resistance between the IUSB pin and ground. In addition, the current out of the IUSB pin is also proportional to the charge current. The system may measure the IUSB pin voltage to monitor the actual charge current, as given in equ.1, during the whole charging cycle.
Analog Control
Figure 38. Dual Internal Power MOSFETs The input voltage is defined as being in a power-good range when satisfying all following three conditions: 1. VIN > VPOR 2. VIN -VBAT > VOS 3. VIN < VOVP where VIN can be either the AC or the USB input voltage. Only one of the two inputs is selected as the power source to charge the battery at a time. The AC input is selected if the USBEN voltage is a low logic level, and the USB input is selected when the USBEN voltage is high logic level.
CHARGE CURRENT LIMIT
The charge current is limited by multiple factors. When the voltage difference between the input and the battery (VAC -VBAT or VUSB -VBAT) is low, (VAC -VBAT)/ RDS(ON)AC or (VUSB -VBAT)/RDS(ON)USB may be less than the corresponding programmed CC-mode current. The charge current is, in this case, limited by (VAC -VBAT)/RDS(ON)AC or (VUSB -VBAT)/RDS(ON)USB. When the voltage difference between the input and the battery is too high, the large power dissipation may lead to the thermal-foldback operation due to the die-temperature regulation. The charge current is reduced to prevent further temperature rise (See the Thermal current foldback section for more information).
DC INPUT INDICATOR
The 34676 uses PPR pin to indicate the DC input power presence. When both the AC and the USB input voltages are under the power-on-reset threshold voltage, or above the over-voltage protection threshold voltage, the PPR outputs high-impedance. In any other conditions, the PPR outputs low voltage. The PPR output is only controlled by the input voltage. All other functions, such as the enable signal and the Input-and-Battery-Voltage Comparator, do not affect the PPR output.
OVER-VOLTAGE PROTECTION (OVP)
Both the USB charger and the AC charger have an OVP threshold as specified in the Static Electrical Characteristics table. When an input voltage is higher than its OVP threshold, the input voltage does not meet the power-good condition, and cannot be selected as the input power source. However, the other input power source may still be in the power-good range and charge the battery. The PPR pin outputs highimpedance if both inputs are above its OVP threshold.
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FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES
INPUT AND BATTERY VOLTAGE COMPARATOR
The input and battery voltage comparator monitors the voltage difference between the input voltage and the battery voltage, as shown in Figure 2. The input voltage has to be higher than the battery voltage, for the charger to be enabled. If the input voltage falls below the battery voltage, this block outputs a signal to disable the charger, to prevent the leakage current from the battery to the input. Due to the intrinsic input offset voltage of the comparators, a small positive voltage, VOS, is added. Thus the power MOSFET can be turned on only when the input voltage is higher than the battery voltage by VOS. On the other hand, the added VOS guarantees that the power MOSFET is turned off when the input voltage is lower than the battery voltage.
LIVE SWITCHING BETWEEN CHARGERS
When switching from one charger to the other in the middle of a charge cycle, the newly turned on charger will start a new charge cycle. When both the AC and the USB inputs are powered, switching the USBEN signal from low to high will force the charging to switch from the AC charger to the USB charger, and switching the USBEN signal from high to low will force the charging to switch form the USB charger to the AC charger. Every time when the switching happens, a new charge cycle will be initialized.
REGULATED OUTPUT
The 34676 has one regulated output, USBOUT. The USBOUT is powered by the USB input. Its regulated output voltage is 4.85 V. When the USB input voltage is below the rising POR threshold, or higher than the OVP threshold, the USBOUT output voltage is zero volts. When the USB input voltage is above the rising POR threshold, and before the linear regulator enters regulation, the output tracks the input voltage with a possible dropout voltage, caused by the on resistance of the pass switch. When the input voltage is higher than the 4.85 V, but lower than the OVP threshold, the output is regulated to 4.85 V. The waveform of the voltage-regulated output vs. the input voltage is summarized in Figure 39.
CHARGER SELECTION INPUT
The USBEN selects either the AC or the USB charger. When the USBEN is driven to a low logic level, the AC charger is selected. When the USBEN is driven to a highlogic level, the USB charger is selected. The USBEN is internally pulled low by a weak current source.
BATTERY DETECTION INPUT
The battery detection input, BATDET, detects the connection of the battery, and is an enable input for the charger. The BATDET comparator has a threshold of 1.75 V (typical). When this pin is driven below this threshold, the charger is enabled. When driven higher than the 1.75 V threshold, the charger is disabled. The BATDET pin is internally pulled up by a 4.0 A current source. The BATDET input does not affect the PPR signal.
VUSB VOVPR VPORR 4.85V VUSBOUT VOVPF VPORF
THERMAL CURRENT FOLDBACK
An internal thermal feedback loop begins to reduce the charge current when the die temperature reaches 110oC, to prevent further temperature rise. This feature protects the 34676 from over-temperature failure, and allows the user to push the limits of the power handling capability of a given circuit board, without the risk of damaging the 34676. The charge current can be set according to the typical (not the worst case) ambient temperature, with the assurance that the charger will automatically reduce the current in worst-case conditions.
Figure 39. Voltage Regulated Output vs. Input Voltage The regulated output is only controlled by the input voltage, and independent on the enable or the other inputs. When the USB input is powered, the USBOUT will output 4.85 V.
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FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES
STATE DIAGRAM
Both AC and USB inputs below POR threshold
PWR OFF
Charger: OFF PPR: H VUSB > VPOR or VAC > VPOR
Anytime charger disabled
Not Enabled
EN VERIFICATION
Charger: OFF PPR: L
Power good
POR
Charger: OFF PPR: L
OV fault removed
Enabled
OV FAULT
Charger: OFF PPR: H CHG: H
TRICKLE CHARGE
Charger: ON PPR: L CHG: L VBAT > VTRK VBAT drops below VTRK
Anytime an OV Fault occurs
FAST CHARGE
Charger: ON PPR: L CHG: L VBAT > VRCH and IBAT < IEOC VBAT < VRCH
CHARGE COMPLETE
Charger: ON PPR: L CHG: H
Figure 40. Charge Cycle State Diagram
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TYPICAL APPLICATIONS APPLICATION INFORMATION
TYPICAL APPLICATIONS
APPLICATION INFORMATION
INPUT CAPACITOR
The input capacitor is used to minimize the input voltage transient that may cause instability when the input voltage is near VBAT+VOS. Typically a 1.0 F X5R ceramic capacitor is sufficient for most applications.
THERMAL CONSIDERATIONS
The 34676 is available in a 3x3 thermally-enhanced UDFN package. A careful thermal design must be considered. The thermal pad needs to be well soldered to a large copper ground plane on the component layer. If the component layer is space limited and does not allow a large copper plane, the thermal pad needs to be connected to other layers through a via array. This increases the actual charge current capability of the 34676.
OUTPUT CAPACITOR
For stable operation, an X5R ceramic capacitor of 1.0F minimum value is needed in parallel with the battery. Depending on the load transient current, a larger capacitance may be required.
DUAL-INPUT CHARGER
Figure 41 shows a typical application using the 34676. C1 and C2 are typically 1.0 F/X5R/16 V ceramic capacitors. C3 is a typically a 0.1 F/X5R/6.3 V ceramic capacitor. C4 usually is a combination of multiple capacitors that are connected to the BAT bus. The charger will be stable with a minimum of a 1.0 F/X5R/6.3 V ceramic capacitor when a battery is connected. When no battery is connected, a minimum of a 10 mA load current is required for the charger output to be stable in CV phase. All connections to the MCU are optional. The voltage output of the ISET and the IUSB pin can be monitored by an analog-to-digital input of the MCU, for charge current measurement. The USBEN pin requires no pull-up resistors. The MCU can choose the AC charger or the USB charger, by controlling the USBEN pin voltage. Since the BATDET sources 6.0 A (maximum) of current and has a 1.65 V (minimum) battery detection threshold, a pull-down resistor less than 275 k should be attached at BATDET, to enable the charger. If the battery pack doesn't have an ID resistor inside, an external resistor is required.
CC-MODE CURRENT SETTING
The CC-mode current of the USB charger, or the AC charger, can be set by external resistors, RIUSB and RISET. A 1% accuracy resistor is recommended to guarantee 5% and 15% CC-mode current accuracy for the AC charger and the USB charger respectively.
EOC CURRENT SETTING
The EOC current can be set by the external resistor, RIMIN. A 1% accuracy resistor is recommended to guarantee the EOC current accuracy.
DROPOUT VOLTAGE
If the input voltage is too low, it may not maintain the programmed CC-mode current, due to the voltage dropout over the power MOSFET. The worst case of RDS(ON) is 500 m for the AC charger and 1000 m for the USB charger. The input voltage should be higher than VBAT + IAC x 500 m for the AC charger, and VBAT + IUSB x 1000 m for the USB charger, to guarantee the programmed CC-mode current.
MC34676B
AC C1 C2 USB GND BAT BATDET USBOUT
C3
C4
IMIN IUSB RIMIN ISET
PPR USBEN CHG
VDDIO
MCU RIUSB RISET AC USB
Figure 41. Dual-input Charger of the MC34676
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TYPICAL APPLICATIONS PACKAGE DIMENSIONS
PACKAGE DIMENSIONS
For the most current package revision, visit www.freescale.com and perform a keyword search using the "98A" listed below.
EP SUFFIX 12-PIN 98ASA10814D REVISION 0
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TYPICAL APPLICATIONS PACKAGE DIMENSIONS
EP SUFFIX 12-PIN 98ASA10814D REVISION 0
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TYPICAL APPLICATIONS PACKAGE DIMENSIONS
EP SUFFIX 12-PIN 98ASA10814D REVISION 0
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REVISION HISTORY
REVISION HISTORY
REVISION 1.0
DATE 10/2007
DESCRIPTION OF CHANGES
* Initial Release
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MC34676 Rev. 1.0 10/2008

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