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Document Number: MC34673

Rev. 1.0, 01/2008

Freescale Semiconductor

Advance Information

* This document contains certain information on a new product.

Specifications and information herein are subject to change without notice.

High Input Voltage 1.2A Charger

for Single-cell Li-Ion Batteries

The MC34673 is a cost-effective fully-integrated battery charger for

Li-Ion or Li-Polymer batteries. The high input voltage, up to 28V,

eliminates the input over-voltage protection circuit required in handheld

devices such as PDAs, cell phones, portable video game players and

digital still cameras.

A typical charge cycle includes trickle, constant-current (CC) and

constant-voltage (CV) charge modes. The CC-mode current is

programmable up to 1.2A with an external resistor. The voltage across

the external resistor is also used to monitor the actual charge current.

The constant voltage is fixed at 4.2V with 0.7% accuracy over a -20°C

to 70°C temperature range. The trickle-mode current is preset to 20%

of the CC-mode current when the battery voltage is lower than the

trickle-mode threshold. The end-of-charge (EOC) current threshold is

preset to 10% of the CC-mode current to save the board space and

cost. A charge current thermal foldback feature limits the charge

current when the IC internal temperature rises to a preset threshold.

The MC34673 also protects the system with its input over-voltage

protection (OVP) feature. In addition, the MC34673 has a 2.6V falling

power-on-reset (POR) threshold, making it perfect to work with current

limited power supplies. Three indication pins (

PPR, CHG and FAST)

can be simply interfaced to a microprocessor or LEDs. When no power

supply is connected, or when disabled, the charger draws less than

1.0µA leakage current from the battery.

Features

• No external MOSFET, reverse-blocking diode or current-sense resistor are required

• Guaranteed maximum 1.2A programmable CC-mode current

• ±0.7% voltage accuracy over -20°C to 70°C

• ±6% current accuracy over -40°C to 85°C

• 28V maximum voltage for the power input with 6.8V over-voltage protection threshold

• 2.6V minimum input operating voltage

• Trickle charge for fully discharged batteries

• Charge current monitor

• Charge current thermal foldback

• Pb-free packaging designated by suffix code EP

Figure 1. 34673 Simplified Application Diagram

POWER MANAGEMENT IC

EP SUFFIX (PB-FREE)

98ASA10774D

8-PIN UDFN

34673

ORDERING INFORMATION

Device

Temperature

Range (T

)

Package

MC34673AEP/R2 -40°C to 85°C 8-UDFN

OFF

VIN

GND

CHG

PPR

BAT

ISET

FAST

TO BATTERY

TO MCU

34673

OUT

ISET

Summary of content (22 pages)

PAGE 1
Freescale Semiconductor Advance Information Document Number: MC34673 Rev. 1.0, 01/2008 High Input Voltage 1.2A Charger for Single-cell Li-Ion Batteries The MC34673 is a cost-effective fully-integrated battery charger for Li-Ion or Li-Polymer batteries. The high input voltage, up to 28V, eliminates the input over-voltage protection circuit required in handheld devices such as PDAs, cell phones, portable video game players and digital still cameras.
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INTERNAL BLOCK DIAGRAM INTERNAL BLOCK DIAGRAM VIN BAT – VIN Monitor Internal Supply + VREF Charge Control REF ISET – PPR + VOS IREF VIN + – + BAT – – + Die Temp 110°C CHG EN Logic Control + – IEOC FAST GND Figure 2.
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PIN CONNECTIONS PIN CONNECTIONS VIN 1 8 BAT PPR 2 7 ISET CHG 3 6 FAST EN 4 5 GND EPAD Figure 3. 34673 Pin Connections Table 1. 34673 Pin Definitions A functional description of each pin can be found in the Functional Pin Description section beginning on page 11. Pin Number Pin Name Pin Function Formal Name Definition 1 VIN Input Input supply 2 PPR Output Power present indicator 3 CHG Output Charge indicator 4 EN Input Enable Enable logic input.
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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 Symbol Value Unit ELECTRICAL RATINGS Input Voltage Range V VIN Pin VIN PPR and CHG Pins EN, BAT, ISET, and FAST Pins -0.3 to 28 VPPR, VCHG -0.3 to 12 VEN, VBAT, VISET, VFAST -0.3 to 5.
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ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics Characteristics noted under conditions VIN = 5.0V, -40°C ≤ TA ≤ 85°C, CIN =1µF, COUT = 2.2µF (see Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VIN = 5.0V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit Input Voltage Range(5) VIN 2.6 - 6.
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ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics (continued) Characteristics noted under conditions VIN = 5.0V, -40°C ≤ TA ≤ 85°C, CIN =1µF, COUT = 2.2µF (see Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VIN = 5.0V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit VTRKL 2.6 2.7 2.8 V VTRKLHYS 40 100 150 mV VRECH 4.060 4.100 4.
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ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS Table 4. Dynamic Electrical Characteristics Characteristics noted under conditions VIN = 5.0V, -40°C ≤ TA ≤ 85°C, CIN =1µF, COUT = 2.2µF (Figure 1), unless otherwise noted. Typical values noted reflect the approximate parameter means at VIN = 5.0V and TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit tEOC 5.5 8.0 11 ms fOSC 40.0 50.0 60.
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES Battery Voltage (V) 4.5 Battery Voltage 300 4.0 250 3.5 200 3.0 150 100 2.5 Charge Current 2.0 1.5 0 20 40 60 80 50 Charge Current (mA) 350 5.0 0 100 120 Constant Charge Current ( mA) ELECTRICAL PERFORMANCE CURVES 1500 RISET=3.23 kΩ 1200 900 600 RISET=6.57 kΩ 300 RISET=13.3 kΩ 3.5 4.0 4.5 Charge Time ( min) Figure 4. Complete Charge Cycle VIN = 5.0V, ICHG=300mA, TA = 25°C 4.0 3.8 3.6 5.0 5.5 6.0 6.
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ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES RISET=6.57 kΩ RISET=3.23 kΩ VISET (V) 0.8 0.6 0.4 0.2 0.0 0 200 400 600 800 1000 1200 Charge Current (mA) Figure 10. VISET vs Charge Current VIN = 5.0V, TA = 25°C RISET=6.11 kΩ 600 400 RISET=19.36 kΩ 200 0 -40 -20 0 20 40 60 80 o Temperature ( C) 250 RISET=3.23 kΩ 1200 Charge Current ( mA) 800 Figure 13. Constant Charge Current vs Temperature VIN = 5.0V, VBAT = 3.9V 1500 900 RISET=6.57 kΩ 600 RISET=13.3 kΩ 300 0 0.0 0.5 1.
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450 RDS(ON) ( mΩ) 400 350 300 250 -40 -20 0 20 40 60 80 BAT Pin Supply Current ( µA) ELECTRICAL CHARACTERISTICS ELECTRICAL PERFORMANCE CURVES 1.0 0.8 0.6 0.4 0.2 0.0 -40 -20 40 60 80 Figure 18. BAT Pin Supply Current vs Temperature VBAT = 5.0V, VIN Not Powered or Charger Disabled 2000 4.20 4.15 4.10 4.05 4.00 3.95 -20 0 20 40 60 80 o Temperature ( C) Figure 17. Recharge Voltage Threshold vs Temperature RISET = 25.86kΩ, VIN = 5.
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FUNCTIONAL DESCRIPTION INTRODUCTION FUNCTIONAL DESCRIPTION INTRODUCTION The MC34673 is a fully-integrated Li-Ion and Li-Polymer battery charger in a tiny package. It uses current, voltage and temperature control loops to regulate the charge current. It has up to 28V input voltage rating, which makes the handheld device safe even when connected to a wrong AC adapter.
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FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION MC34673 - Functional Block Diagram Integrated Supply Internal Supply & Reference Sensing & Control VIN Monitor Charge Control Current Setting End of Charge Current Monitor VIN - BAT Compare Power MOSFET Die Temperature Feedback Logic Logic Control Status Indication Integrated Supply Sensing & Control Logic MOSFET Figure 20.
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FUNCTIONAL DESCRIPTION FUNCTIONAL INTERNAL BLOCK DESCRIPTION LOGIC LOGIC CONTROL AND STATUS INDICATION The logic control block determines the on and off of the charger. It takes the signals from the VIN Monitor, VIN-BAT Comparator, EOC, and the external enable signal, and determines the on and off states as well as the charge status indication outputs of the charger (CHG, PPR, and FAST). POWER MOSFET The power MOSFET passes the charging current from the input to the output.
PAGE 14
FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES CHARGE CYCLE outputs logic high voltage at the CHG pin to indicate that the charging is completed. The MC34673 uses the standard charge profile with trickle, constant-current (CC), and constant-voltage (CV) charge modes, as shown in Figure 21. Both the CC and the CV charge modes are also called fast-charge mode.
PAGE 15
FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES the ISET pin voltage to monitor the actual charge current as given in equ. 1 during the whole charging cycle. INPUT POWER PRESENCE INDICATOR CHARGE CURRENT LIMITATION reset voltage threshold (VPOR), the PPR pin outputs a low The charge current is limited by multiple factors.
PAGE 16
FUNCTIONAL DEVICE OPERATION STATE DIAGRAM STATE DIAGRAM PWR OFF VINVPOR EN=high or VIN>VOVP or VINVBAT+VOS VBAT < 2.7V TRICKLE CHARGE VBAT > 2.7V Charger: ON VBAT < 2.7V FAST CHARGE Charger: ON VBAT=4.2V and IBAT < IEOC VBAT<4.10V CHARGE COMPLETE Charger: ON Figure 22.
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TYPICAL APPLICATIONS INTRODUCTION TYPICAL APPLICATIONS INTRODUCTION INPUT CAPACITOR DROPOUT VOLTAGE The input capacitor is used to reduce the input voltage transient that may cause instability. A 1.0µF, X5R, 16V rated ceramic capacitor is recommended for most applications. If the DC input voltage is too low, it may not maintain the programmed CC-mode charge current due to the voltage dropout over the power MOSFET. The worst case of the RDS(ON) is 475mΩ.
PAGE 18
TYPICAL APPLICATIONS APPLICATIONS MCU INTERFACED CHARGER When the charger is used in handheld systems with MCU control, the MC34673 uses PPR to report the DC input status to the MCU. After the MCU pulls the EN pin to a logic-low Input VIN voltage to start charging, the MC34673 reports the charge status through CHG and FAST pins to the MCU. The MCU can also monitor the charge current by measuring the voltage at the ISET pin. Figure 24 is the typical application circuit. BAT 1µF 2.
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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.
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TYPICAL APPLICATIONS PACKAGE DIMENSIONS EP SUFFIX 8-PIN 98ASA10774D REVISION 0 34673 20 Analog Integrated Circuit Device Data Freescale Semiconductor
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REVISION HISTORY REVISION HISTORY REVISION 1.
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