IC SMART BATTERY CHARGER 24-SSOP

LTC4100EG

Manufacturer Part NumberLTC4100EG
DescriptionIC SMART BATTERY CHARGER 24-SSOP
ManufacturerLinear Technology
LTC4100EG datasheet
 


Specifications of LTC4100EG

FunctionCharge ManagementBattery TypeSmart Batteries
Voltage - Supply6 V ~ 28 VOperating Temperature-40°C ~ 85°C
Mounting TypeSurface MountPackage / Case24-SSOP (0.200", 5.30mm Width)
Lead Free Status / RoHS StatusContains lead / RoHS non-compliant  
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FEATURES
n
Single Chip Smart Battery Charger Controller
n
100% Compliant (Rev. 1.1) SMBus Support Allows
for Operation with or without Host
n
SMBus Accelerator Improves SMBus Timing
n
Wide Output Voltage Range: 3.5V to 26V
n
Hardware Interrupt and SMBAlert Response
Eliminate Interrupt Polling
n
High Effi ciency Synchronous Buck Charger
n
0.5V Dropout Voltage; Maximum Duty Cycle > 98%
n
AC Adapter Current Limit Maximizes Charge Rate
n
±0.8% Voltage Accuracy; ±4% Current Accuracy
n
Up to 4A Charging Current Capability
n
10-Bit DAC for Charge Current Programming
n
11-Bit DAC for Charger Voltage Programming
n
User-Selectable Overvoltage and Overcurrent Limits
n
High Noise Immunity SafetySignal Sensor
n
Available in a 24-Pin SSOP Package
APPLICATIONS
n
Portable Instruments and Computers
n
Data Storage Systems and Battery Backup Servers
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6650174 and 5723970.
TYPICAL APPLICATION
DCIN
1.21k
3V
TO 5.5V
CHGEN
ACP
1.13k
54.9k
SMBALERT#
SMBCLK
SMBDAT
DESCRIPTION
The LTC
®
4100 Smart Battery Charger is a single chip
charging solution that dramatically simplifi es construction
of an SBS compliant system. The LTC4100 implements
a Level 2 charger function whereby the charger can be
programmed by the battery or by the host. A SafetySignal
on the battery being charged is monitored for temperature,
connectivity and battery type information. The SMBus
interface remains alive when the AC power adapter is
removed and responds to all SMBus activity directed to
it, including SafetySignal status (via the ChargerStatus
command). The charger also provides an interrupt to the
host whenever a status change is detected (e.g., battery
removal, AC adapter connection).
Charging current and voltage are restricted to chemistry-
specifi c limits for improved system safety and reliability.
Limits are programmable by two external resistors. Ad-
ditionally, the maximum average current from the AC
adapter is programmable to avoid overloading the adapter
when simultaneously supplying load current and charging
current. When supplying system load current, charg-
ing current is automatically reduced to prevent adapter
overload.
0.1μF
13.7k
0.1μF
0.033Ω
LTC4100
17
5
V
DCIN
DD
11
4
5k
DCDIV
INFET
6
24
CHGEN
CLP
10
23
ACP
CLN
7
1
SMBALERT
TGATE
9
3
SCL
BGATE
8
2
SDA
PGND
15
21
THB
CSP
16
22
THA
BAT
13
18
I
V
LIM
SET
14
19
V
I
LIM
TH
20
12
I
GND
6.04k
10k
DC
0.0015μF
0.068μF
0.12μF
SafetySignal
Figure 1. 4A Smart Battery Charger
LTC4100
Smart Battery
Charger Controller
V
PART
BAT
< 5.5V
LTC4101
> 5.5V
LTC4100
SYSTEM LOAD
SMART BATTERY
20μF
0.025Ω
10μH
20μF
100Ω
0.01μF
0.1μF
SMBCLK
SMBDAT
4100 TA01
4100fb
1

LTC4100EG Summary of contents

  • Page 1

    ... Portable Instruments and Computers n Data Storage Systems and Battery Backup Servers L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6650174 and 5723970. ...

  • Page 2

    ... Power-Fail DD DCIN Current in Shutdown 2 PIN CONFIGURATION BGATE CHGEN SMBALERT PART MARKING PACKAGE DESCRIPTION LTC4100EG 24-Lead Plastic SSOP PART MARKING PACKAGE DESCRIPTION LTC4100EG 24-Lead Plastic SSOP http://www.linear.com/leadfree/ http://www.linear.com/tapeandreel/ l The denotes the specifi cations which apply over the full operating = 25° ...

  • Page 3

    ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER Current Sense Amplifi er, CA1 Input Bias Current into BAT Pin CMSL CA1/I Input Common Mode Low 1 CMSH CA1/I Input Common Mode High 1 Current Comparators I ...

  • Page 4

    LTC4100 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER AC Present Comparator V DCDIV Threshold ACP DCDIV Hysteresis DCDIV Input Bias Current ACP V OH ACP V OL DCDIV to ACP Delay SafetySignal Decoder SafetySignal Trip ...

  • Page 5

    ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER Logic Levels V SCL/SDA Input Low Voltage IL V SCL/SDA Input High Voltage IH V SDA Output Low Voltage OL I SCL/SDA Input Current IL I SCL/SDA Input ...

  • Page 6

    LTC4100 TYPICAL PERFORMANCE CHARACTERISTICS INFET Response Time to Reverse Current V OF PFET (2V/DIV PFET (5V/DIV (REVERSE PFET (5A/DIV 1.25μs/DIV TEST ...

  • Page 7

    TYPICAL PERFORMANCE CHARACTERISTICS Charging Current Error 0 TEMP = 27°C 0 12V LOAD 0.2 0.1 0 –0.1 –0.2 –0.3 –0 CHARGING CURRENT (A) PIN FUNCTIONS TGATE (Pin 1): Drives the Top ...

  • Page 8

    LTC4100 PIN FUNCTIONS I (Pin 13): An external resistor is connected between this LIM pin and GND. The value of the external resistor programs the range and resolution of the programmed charger cur- rent. This is a digital, not an ...

  • Page 9

    BLOCK DIAGRAM C4 R4 0.01μF 100Ω V SET V BAT 18 C5, 0.1μF GND 12 WATCHDOG SYSTEM LOAD 20μF CLP L1 TGATE 1 CSP Q2 D1 BGATE PGND 2 CLN CLP 24 DCIN ...

  • Page 10

    LTC4100 TEST CIRCUIT 1.19V – CSP BAT V SET LT1055 OPERATION Overview (Refer to Block Diagram) The LTC4100 is composed of a battery charger section, a charger controller, a 10-bit DAC to control charger current, an ...

  • Page 11

    OPERATION While the top MOSFET is off, the bottom MOSFET is turned on until either the inductor current trips the current comparator the beginning of the next cycle. The REV oscillator uses the equation – ...

  • Page 12

    LTC4100 OPERATION Description of Supported Battery Charger Functions The functions are described as follows (see Table 1 also): FunctionName() ‘hnn (command code) Description: A brief description of the function. Purpose: The purpose of the function, and an example where appropriate. ...

  • Page 13

    OPERATION Table 1. Summary of Supported Charger Functions Function Access Address ChargerSpecInfo() 7'b0001_001 Read ChargerMode() 7'b0001_001 Write ChargerStatus() 7'b0001_001 Read ChargingCurrent() 7'b0001_001 Write ChargingVoltage() 7'b0001_001 Write AlarmWarning() 7'b0001_001 Write LTCO() 7'b0001_001 Write Read Alert Response 7'b0001_100 Address Read Byte SMBus ...

  • Page 14

    LTC4100 OPERATION The RES_COLD bit is set only when the SafetySignal re- sistance value is greater than 28.5kΩ. The SafetySignal indicates a cold battery. The RES_COLD bit will be set whenever the RES_OR bit is set. The RES_HOT bit is ...

  • Page 15

    OPERATION Input: The CHARGING_VOLTAGE is an unsigned 16-bit integer specifying the requested charging voltage in mV. The LTC4100 considers any value from 0x0001 through 0x049F the same as writing 0x0000. The following table defi nes the maximum permissible value of ...

  • Page 16

    LTC4100 OPERATION • Change of BATTERY_PRESENT in the ChargerStatus() function. • Setting ALARM_INHIBITED in the ChargerStatus() function. • Internal power-on reset condition. SMBus Accelerator Pull-Ups Both SCL and SDA have SMBus accelerator circuits which reduce the rise time on systems ...

  • Page 17

    OPERATION 9. There is insuffi cient DCIN voltage to charge the battery. The LTC4100 will resume wake-up charging when there is suffi cient DCIN voltage to charge the battery. This condition will not reset the T TIMEOUT Controlled Charging Algorithm ...

  • Page 18

    LTC4100 OPERATION SafetySignal sensing is accomplished by a state machine that reconfi gures the switches of Figure 4 using THA_SELB and THB_SELB, a selectable reference generator, and two comparators. This circuit has two modes of operation based upon whether AC ...

  • Page 19

    OPERATION The I Decoder Block LIM The value of an external resistor connected from this pin to GND determines one of four current limits that are used for maximum charging current value. These limits provide a measure of safety with ...

  • Page 20

    LTC4100 OPERATION The Current DAC Block The current DAC is a delta-sigma modulator which controls the effective value of an external resistor, R set the current limit of the charger. Figure simplifi ed diagram of the DAC ...

  • Page 21

    APPLICATIONS INFORMATION Adapter Limiting An important feature of the LTC4100 is the ability to auto- matically adjust charging current to a level which avoids overloading the wall adapter. This allows the product to operate at the same time that batteries ...

  • Page 22

    LTC4100 APPLICATIONS INFORMATION I is the full-scale charge current. Chose the lowest MAX I value that is still above your expected battery charge MAX current as requested over the SMBus. If you deviate from the resistance values shown in Table ...

  • Page 23

    APPLICATIONS INFORMATION The MOSFET power dissipations at maximum output current are given by δΔT)R 2 PMAIN = OUT IN MAX )(C )(f IN MAX RSS PSYNC = (V – ...

  • Page 24

    LTC4100 APPLICATIONS INFORMATION b) I current is due to SafetySignal (thermistor pin) THRM sampling that will vary with the presence of DC power being on or off. DCDIV is detected every 32ms. RTHX is the value of the safety signal ...

  • Page 25

    APPLICATIONS INFORMATION Soft-Start and Undervoltage Lockout The LTC4100 is soft-started by the 0.12μF capacitor on the I pin. On start-up, I pin voltage will rise quickly 0.5V, then ramp rate set by the internal ...

  • Page 26

    LTC4100 APPLICATIONS INFORMATION Protecting SMBus Inputs The SMBus inputs, SCL and SDA, are exposed to uncon- trolled transient signals whenever a battery is connected to the system. If the battery contains a static charge, the SMBus inputs are subjected to ...

  • Page 27

    APPLICATIONS INFORMATION PCB Layout Considerations For maximum effi ciency, the switch node rise and fall times should be minimized. To prevent magnetic and electrical fi eld radiation and high frequency resonant problems, proper layout of the components connected to the ...

  • Page 28

    LTC4100 PACKAGE DESCRIPTION 7.8 – 8.2 0.42 ±0.03 RECOMMENDED SOLDER PAD LAYOUT 5.00 – 5.60** (.197 – .221) 0.09 – 0.25 0.55 – 0.95 (.0035 – .010) (.022 – .037) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN ...

  • Page 29

    ... Added ‘SafetySignal (Thermistor) Value’ Section Changes to Typical Application 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC4100 ...

  • Page 30

    ... Charger with Termination LTC4008 High Effi ciency, Programmable Voltage/Current Battery Charger LTC4101 Smart Battery Charger Controller LTC4412 Low Loss PowerPath™ Controller PowerPath is a trademark of Linear Technology Corporation. 30 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ...