Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - battery management Charge indicator Li-Ion, NiCd, NiMH MSOP 10 Surface-mount

LTC4150

4150fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Coulomb Counter/

Battery Gas Gauge

The LTC

4150 measures battery depletion and charging

in handheld PC and portable product applications. The

device monitors current through an external sense resistor

between the battery’s positive terminal and the battery’s

load or charger. A voltage-to-frequency converter trans-

forms the current sense voltage into a series of output

pulses at the interrupt pin. These pulses correspond to a

ﬁ xed quantity of charge ﬂ owing into or out of the battery.

The part also indicates charge polarity as the battery is

depleted or charged.

The LTC4150 is intended for 1-cell or 2-cell Li-Ion and

3-cell to 6-cell NiCd or NiMH applications.

Integral Nonlinearity, % of Full Scale

Indicates Charge Quantity and Polarity

±50mV Sense Voltage Range

Precision Timer Capacitor or Crystal Not Required

2.7V to 8.5V Operation

High Side Sense

32.55Hz/V Charge Count Frequency

1.5μA Shutdown Current

10-Pin MSOP Package

Battery Chargers

Palmtop Computers and PDAs

Cellular Telephones and Wireless Modems

–

INT

4.7μF

CLR

CHG

DISCHG

SENSE

POL

SHDN

4.7μF

CHARGER

LOAD

SENSE

–

SENSE

GND

LTC4150 μP

4150 TA01a

CURRENT SENSE VOLTAGE (mV)

–50

–25 0 25 50

ERROR (% FULL SCALE)

4150 TA01b

0.5

0.4

0.3

0.2

0.1

–0.5

–0.4

–0.3

–0.2

–0.1

L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode are registered trademarks and

ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All other trademarks

are the property of their respective owners.

Summary of content (14 pages)

PAGE 1
LTC4150 Coulomb Counter/ Battery Gas Gauge FEATURES DESCRIPTION n The LTC®4150 measures battery depletion and charging in handheld PC and portable product applications. The device monitors current through an external sense resistor between the battery’s positive terminal and the battery’s load or charger. A voltage-to-frequency converter transforms the current sense voltage into a series of output pulses at the interrupt pin.
PAGE 2
LTC4150 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage (VDD) .................................. –0.3V to 9V Input Voltage Range Digital Inputs (CLR, SHDN) ........–0.3V to (VDD + 0.3) SENSE–, SENSE+ , CF–, CF+ .........–0.3V to (VDD + 0.3) Output Voltage Range Digital Outputs (INT, POL) ....................... –0.3V to 9V Operating Temperature Range LTC4150CMS ........................................... 0°C to 70°C LTC4150IMS .......................................
PAGE 3
LTC4150 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VDD = 2.7V and 8.5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply Current IDD Supply Current, Operating VDD = 8.5V VDD = 2.7V l l 115 80 140 100 μA μA IDD(SD) Supply Current, Shutdown VDD = 8.5V VDD = 5.5V VDD = 2.7V l l l 10 22 10 1.5 μA μA μA l 32.55 33.1 33.3 Hz/V Hz/V 0 0.
PAGE 4
LTC4150 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Voltage to Frequency Gain vs Temperature +1.00 +1.00 +0.75 +0.75 +0.50 +0.25 VSENSE = 25mV 0 VSENSE = 50mV –0.25 –0.50 –0.75 Operating IDD vs VDD 140 VSENSE = 50mV 120 +0.50 VDD = 2.7V +0.25 0 VDD = 8.5V 100 –0.25 –0.50 80 –0.75 –1.00 2 3 4 5 6 VDD (V) 7 8 –1.00 -50 9 60 -25 0 25 50 75 TEMPERATURE (°C) 100 4150 G01 125 400 VOL (mV) 4 2 1 2.60 IOL = 1.6mA 350 2.59 300 2.
PAGE 5
LTC4150 PIN FUNCTIONS SENSE+ (Pin 1): Positive Sense Input. This is the noninverting current sense input. Connect SENSE+ to the load and charger side of the sense resistor. Full-scale current sense input is 50mV. SENSE+ must be within 60mV of VDD for proper operation. SENSE– (Pin 2): Negative Sense Input. This is the inverting current sense input. Connect SENSE– to the positive battery terminal side of the sense resistor. Full-scale current sense input is 50mV.
PAGE 6
LTC4150 BLOCK DIAGRAM CHARGER LOAD VDD 8 OFLOW/ UFLOW S 200k CF+ 200k CONTROL LOGIC AMPLIFIER 3 + CF + 4 CF– COUNTER – – Q R S1 2k 1 IBAT 10 INT + 100pF SENSE+ RSENSE REFHI 1.7V S3 9 CLR UP/DN CHARGE 6 POL POLARITY DETECTION DISCHARGE 200k 2k – 2 SENSE– S2 REFLO 0.95V 5 SHDN GND 7 4150 F01 Figure 1. Block Diagram TIMING DIAGRAMS CLR 50% 50% tCLR INT INT 4150 F02 50% 50% tINT 4150 F03 Figure 2.
PAGE 7
LTC4150 OPERATION Charge is the time integral of current. The LTC4150 measures battery current by monitoring the voltage developed across a sense resistor and then integrates this information in several stages to infer charge. The Block Diagram shows the stages described below. As each unit of charge passes into or out of the battery, the LTC4150 INT pin interrupts an external microcontroller and the POL pin reports the polarity of the charge unit.
PAGE 8
LTC4150 APPLICATIONS INFORMATION SENSE VOLTAGE INPUT AND FILTERS Coulomb Counting Since the overall integration time is set by internally trimming the LTC4150, no external timing capacitor or trimming is necessary. The only external component that affects the transfer function of interrupts per coulomb of charge is the sense resistor, RSENSE. The common mode range for the SENSE+ and SENSE– pins is VDD ±60mV, with a maximum differential voltage range of ±50mV.
PAGE 9
LTC4150 APPLICATIONS INFORMATION INT, POL and CLR Interfacing to INT, POL, CLR and SHDN INT asserts low each time the LTC4150 measures a unit of charge. At the same time, POL is latched to indicate the polarity of the charge unit. The integrator and counter continue running, so the microcontroller must service and clear the interrupt before another unit of charge accumulates. Otherwise, one measurement will be lost.
PAGE 10
LTC4150 APPLICATIONS INFORMATION AUTOMATIC CHARGE COUNT INTERRUPT AND CLEAR In applications where a CLR pulse is unavailable, it’s easy to make the LTC4150 run autonomously, as shown in Figures 5 and 6. If the microcontroller VCC is less than or equal to the battery VDD, INT may be directly connected to CLR, as in Figure 5. The only requirement is that the microcontroller should be able to provide a high logic level of 1.9V to SHDN. If the microcontroller VCC is greater than the battery VDD, use Figure 6.
PAGE 11
LTC4150 APPLICATIONS INFORMATION PC BOARD LAYOUT SUGGESTIONS TO CHARGER Keep all traces as short as possible to minimize noise and inaccuracy. The supply bypass capacitor C2 should be placed close to the LTC4150. The 4.7μF ﬁlter capacitor CF should be placed close the CF+ and CF – pins and should be a low leakage, unpolarized type.
PAGE 12
LTC4150 PACKAGE DESCRIPTION MS Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1661 Rev E) 0.889 p 0.127 (.035 p .005) 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 3.00 p 0.102 (.118 p .004) (NOTE 3) 0.50 0.305 p 0.038 (.0197) (.0120 p .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 10 9 8 7 6 3.00 p 0.102 (.118 p .004) (NOTE 4) 4.90 p 0.152 (.193 p .006) DETAIL “A” 0.497 p 0.076 (.0196 p .003) REF 0o – 6o TYP GAUGE PLANE 1 2 3 4 5 0.53 p 0.152 (.021 p .006) DETAIL “A” 0.86 (.
PAGE 13
LTC4150 REVISION HISTORY (Revision history begins at Rev C) REV DATE DESCRIPTION C 2/10 Added Conditions to Power Supply Current in Electrical Characteristics PAGE NUMBER 3 4150fc 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.
PAGE 14
LTC4150 TYPICAL APPLICATION CHARGER LOAD SENSE+ 1.2Ω 1.1Ω INT CD40110B LTC4150 CLR 100mΩ SENSE– CD40110B + CD40110B SENSE RESISTANCE = 0.0852Ω IMAX = 588mA 10,000 PULSES = 1Ah CD40110B CD40110B 4150 F09 Figure 9.