bq2057 Advanced Li-Ion Linear Charge Management IC Features General Description Pin Names Pin Connections

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1 bq05 Advanced Li-Ion Linear Charge Management IC Features Ideal for single- and dual-cell Li-Ion packs with coke or graphite anodes Dropout voltage as low as 0.V AutoComp dynamic compensation of battery pack s internal impedance Optional temperature-monitoring before and during charge Integrated voltage and current regulation with programmable charge-current and high- or low-side current sensing Integrated cell conditioning for reviving deeply discharged cells and minimizing heat dissipation during initial stage of charge Better than ±% voltage regulation accuracy Charge status output for LED or host processor interface Automatic battery-recharge feature Charge termination by minimum current Low-power sleep mode Packaging: -pin SOIC, -pin SOP Pin Connections General Description The BENCHMARQ bq05 series advanced Li-Ion linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp charge-rate compensation in a single -pin IC. The bq05 continuously measures battery temperature using an external thermistor. For safety reasons, the bq05 inhibits charge until the battery temperature is within user-defined thresholds. The bq05 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold V MIN, the bq05 trickle-charges to condition the battery. The conditioning charge rate is set at 0% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of charge. After conditioning, the bq05 applies a constant current to the battery. An external sense-resistor sets Pin Names the magnitude of the current. The sense-resistor can be on either the low or the high side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The bq05 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±% over the operating-temperature and supply-voltage ranges. For single and dual cells with either coke or graphite anodes, the bq05 is offered in four fixed-voltage versions:.v,.v,.v, and.v. Charge stops when the current tapers to the charge termination threshold, V TERM. The bq05 automatically restarts the charge if the battery voltage falls below the V RCH threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. Current-sense input STAT Charge status output Battery-voltage input Supply voltage Temperature sense input Ground input Charge control output Charge-rate compensation input 5 STAT -Pin PDIP, Narrow SOIC, or SOP PN-050.eps SLUS05A JANUARY REVISED MAY 000

2 bq05 Pin Descriptions Current-sense input Battery current is sensed via the voltage developed on this pin by an external sense resistor. Battery voltage input Voltage sense-input tied directly to the positive side of the battery. supply input Temperature sense input Input for an external battery-temperature monitoring circuit. Connecting this input to Vcc/ disables this feature. STAT Charge status output Tri-state indication of charge-in-progress, charge-complete, and temperature fault. Ground input Charge-control output Source-follower output that drives an external pass-transistor for current and voltage regulation. Charge-rate compensation input Sets the charge-rate compensation level. The voltage-regulation output may be programmed to vary as a function of the charge current delivered to the battery. POWER ON RESET K V REG CONTROL BLOCK V V LED STAT STAT V, V 05FBD.eps Figure. Functional Block Diagram

3 bq05 Sleep Mode LED = Hi-Z NO > V YES YES Temperature Check > V < V NO Temperature Fault LED = Hi-Z V V MIN YES Conditioning Phase LED = High NO Current Regulation Phase LED = High Voltage Regulation Phase LED = HIGH NO I I REG 0 YES Charge Complete LED = LOW V V RCH YES 05OFC.eps NO Figure. bq05 Operational Flow Chart Functional Description Figure is a functional block diagram, Figure an operational flow chart, and Figure a typical charger schematic for the bq05. Charge Qualification and Conditioning When power is applied, the bq05 starts a charge-cycle if a battery is already present or when a battery is inserted. Charge qualification is based on battery temperature and voltage. The bq05 suspends charge if the battery temperature is outside the V to V range and suspends charge until the battery temperature is within the allowed range. The bq05 also checks the battery voltage. If the battery voltage is below the low-voltage threshold V MIN, the bq05 uses trickle-charge to condition the battery. The conditioning charge rate I COND is set at 0% of the regulation current. The conditioning current also minimizes heat dis-

4 bq05 0.Ω Q FZTB D * PACK+ C 0.µF R kω bq05 V VSS STAT 5 D R T C 0.µF PACK- TEMP NTC Battery Pack R kω R T * Optional. 05ldc.eps Figure. Low-Dropout Single- or Dual-Cell Li-Ion Charger sipation in the external pass-element during the initial stage of charge. See Figure for a typical charge-algorithm. Current Regulation The bq05 regulates current while the battery-pack voltage is less than the regulation voltage, V REG. The bq05 monitors charge current at the input by the voltage drop across a sense-resistor,, in series with the battery pack. In high-side current sensing configuration (Figure 5), is placed between the Vcc and pins, and in low-side sensing (Figure ) the is placed between Vss (battery negative) and (charger ground) pins. Charge-current feedback, applied through pin, maintains regulation around a threshold of V. The following formula calculates the value of the sense resistor: = V I REG where I REG is the desired charging current. Voltage Monitoring and Regulation Voltage regulation feedback is through pin. This input is tied directly to the positive side of the battery pack. The bq05 monitors the battery-pack voltage between the and pins. The bq05 is offered in four fixed-voltage versions for single- and dual-cells with either coke or graphite anodes:.v,.v,.v, and.v. Other regulation voltages can be achieved by adding a voltage divider between the positive and negative terminals of the battery pack. The voltage divider presents a scaled battery pack voltage to input. (See Figures and.) The resistor values R B and R B for the voltage divider are calculated by the following equation: R R B B = N V V CELL REG where N = Number of cells in series V CELL = Desired regulation voltage per cell Charge Termination and Re-Charge The bq05 monitors the charging current during the voltage-regulation phase. The bq05 declares a batterycomplete condition and terminates charge when the current tapers off to the charge termination threshold, V TERM. A new charge cycle begins when the battery voltage falls below the VRCH threshold.

5 bq05 Low-Current Conditioning Phase Current Regulation Phase Voltage Regulation Phase (Shown with the optional AutoComp feature) V PACK V REG I REG V MIN V I I I REG COND = I FULL = 0 I REG 0 GR05b.eps Figure. bq05 Typical Charge Algorithm bq05 + bq05 V SS + 05HSCS.eps LSCS.eps Figure 5. High-Side Current Sensing Figure. Low-Side Current Sensing 5

6 bq05 + R B + bq05 R B R B - bq05 R B - 05OVDHSC.eps 05OVDLSC.eps Figure. Optional Voltage Divider for Non-Standard Regulation Voltage, (High-Side Current Sensing) Figure. Optional Voltage Divider for Non-Standard Regulation Voltage, (Low-Side Current Sensing) Temperature Monitoring The bq05 continuously monitors temperature by measuring the voltage between the and pins. A negative- or a positive-temperature coefficient thermistor (NTC, PTC) and an external voltage-divider typically develop this voltage. (See Figure 9.) The bq05 compares this voltage against its internal V and V thresholds to determine if charging is allowed. (See Figure 0.) The temperature sensing circuit is immune to any fluctuation in the, since both the external voltage divider and the internal thresholds (V and V ) are referenced to. The resistor values of R T and R T are calculated by the following equations: For NTC thermistors ( 5 RTH RTC) R T = RTC - RTH R T = ( ( )) ( 5 RTH RTC) (( RTC) ( RTH) ) + + RT RT bq05 R T Thermistor R T - bq05 - Thermistor High-Side Current Sensing Low-Side Current Sensing 05C.eps Figure 9. Temperature Sensing Circuits

7 bq05 Temp Fault Condition Battery conditioning and charging Charge complete Temperature fault or sleep mode STAT Pin High Low High-Z For PTC thermistors R T = V Normal Temp Range V Temp Fault 05IT.eps Figure 0. bq05 Input Thresholds R T = 5 RTH R TC ( ( RTH -RTC)) ( 5 RTH RTC) (( RTH) ( RTC) ) Automatic Charge-Rate Compensation To reduce charging time, the bq05 uses the proprietary AutoComp technique to compensate safely for internal impedance of the battery pack. Figure outlines the major components of a single-cell Li-Ion battery pack. The Li-Ion battery pack consists of a cell, protection circuit, fuse, connector, current sense-resistors, and some wiring. Each of these components contains some resistance. Total impedance of the battery pack is the sum of the minimum resistances of all battery-pack components. Using the minimum resistance values reduces the odds for overcompensating. Overcompensating may activate the safety circuit of the battery pack. Compensation is through input pin (Figure ). A portion of the current-sense voltage, presented through this pin, is scaled by a factor of K and summed with the regulation threshold, V REG. This process increases the output voltage to compensate for the battery pack s internal impedance and for undesired voltage drops in the circuit. where R TC is the cold-temperature resistance and R TH is the hot-temperature resistance of the thermistor, as specified by the thermistor manufacturer. R T or R T can be omitted if only one temperature setting (Hot or Cold) is required. Applying a voltage between the V and V thresholds to pin disables the temperature-sensing feature. Low-Power Mode The bq05 enters the sleep mode if the falls below the voltage at the input. This feature prevents draining the battery pack during the absence of. Charge Status Display The bq05 reports the status of the charger on the tri-state STAT pin. The three states include charge in progress, charge complete, and temperature fault. Terminal + Terminal - Wire R FUSE Discharge Protection Controller Wire Wire Charge Wire Cell 05SCLIP.eps Figure. Typical Components of a Single-Cell Li-Ion Pack

8 bq05 R R bq05 + bq05 R R + High-Side Current Sensing Low-Side Current Sensing - 05AC.eps Figure. AutoComp Circuits AutoComp setup requires the following information: Total impedance of battery pack (Z PACK) Maximum charging current (I REG) The voltage drop VZ across the internal impedance of the battery pack can then be calculated by V Z = Z PACK I REG The required compensation is then calculated using the following equations: where V is the voltage on pin. This voltage is referenced to Vcc in high-side current-sensing configuration and to Vss for low-side sensing. V PACK is the voltage across the battery pack. The values of R and R can be calculated using the following equation: V V = R R + R V = V K Z V PACK = V REG + (K V )

9 bq05 Absolute Maximum Ratings Symbol Parameter Min. Max. Units Notes relative to V V T relative to V DC voltage applied on any pin (excluding ) T OPR Operating ambient temperature -0 0 C T STG Storage temperature -0 5 C P D Power dissipation 00 mw DC Thresholds (TA=TOPR and V =.5 5V unless otherwise specified) Symbol Parameter Rating Tolerance Unit Notes.0 ±% V For bq05 only; See Note,, V REG V V MIN Voltage regulation reference Current regulation reference Conditioning voltage reference.0 ±% V For bq05c only; See Note,,.0 ±% V For bq05t only; See Note,,.0 ±% V For bq05w only; See Note,, -0 ±0% mv = 5V, See Note -5 ±0% mv = 9V, See Note -5 ±5% mv All other, See Note.0 ±% V For bq05 only. ±% V For bq05c only.0 ±% V For bq05t only. ±% V For bq05w only K AutoComp gain. ±5% V/V See Note V Lower temperature threshold 0. ±% of V Voltage at pin, relative to V Upper temperature threshold 0. ±% of V Voltage at pin, relative to V RCH Recharge threshold V REG - 0. ±% V Voltage on pin, bq05 and bq05c only V RCH Recharge threshold V REG - 0. ±% V Voltage on pin, bq05t and bq05w only V TERM Charge termination reference - ±0mV mv See Note Notes:. = V + 0.V to 5V.. For high-side current-sensing configuration.. For low-side current-sensing, the tolerance is ±% for TA = 5 C and ±.% for TA = TORR.. Voltage at pin, relative to V for high-side sensing, and to VSS for low-side sensing, 0 C <= TA <= 50 C abcdefghijklmnopqrstuvwxyz590-= []\;,./ 9 ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#%^&*()_+{} :"<>?~

10 bq05 DC Electrical Characteristics (TA= TOPR, and V =.5-5V unless otherwise specified)) Symbol Parameter Min Typical Max Units Notes Supply voltage.5-5 V I Operating current - ma Excluding external loads I S Sleep current - µa For bq05 and bq05c, See note µa For bq05t and bq05w, See note V OL Output-low voltage V I OL = 0mA; STAT pin V OH Output-high voltage V I OH = 5mA; STAT pin I IH Input leakage current - - µa input, V = V REG µa,, and inputs, V = V = V = 5V I SNK Sink current 5-0 ma pin, not to exceed P D specification V OL pin output-low voltage V At I SNK (minimum) Note: V V MIN,V - 0.V, +0 C T A 0 C. -Pin SOIC Narrow (SN) -Pin SN (0.50" SOIC) Inches Millimeters Dimension Min. Max. Min. Max. A A B C D E e H L

11 bq05 : -Pin SOP Dimension Inches Millimeters Min. Max. Min. Max. A A B C D E e 0.05BSC 0.5BSC H Notes:. Controlling dimension: millimeters. Inches shown for reference only. 'D' and 'E' do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.5mm per side Each lead centerline shall be located within ±0.0mm of its exact true position.. Leads shall be coplanar within 0.0mm at the seating plane. 5 Dimension 'B' does not include dambar protrusion. The dambar protrusion(s) shall not cause the lead width to exceed 'B' maximum by more than 0.0mm. Dimension applies to the flat section of the lead between 0.0mm and 0.5mm from the lead tip. 'A' is defined as the distance from the seating plane to the lowest point of the package body (base plane). Ordering Information bq05 Package Option: SN = -pin narrow SOIC = -pin SOP Device: bq05 Advanced Li-Ion Linear Charger for One Cell (.V) bq05c Advanced Li-Ion Linear Charger for One Cell (.V) bq05t Advanced Li-Ion Linear Charger for Two Cells (.V) bq05w Advanced Li-Ion Linear Charger for Two Cells (.V)

12 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUC MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ( CRITICAL APPLICATIONS ). TI SEMICONDUCTOR PRODUC ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUC IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER S RISK. In order to minimize risks associated with the customer s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI s publication of information regarding any third party s products or services does not constitute TI s approval, warranty or endorsement thereof. Copyright 000, Texas Instruments Incorporated

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