DV2057/C/T/W Advanced Li-Ion Charger Development System Control of On-Board Linear Regulator Features ➤ bq2057 charge-control evaluation and development system for single- and dual-cell Li-Ion packs with coke or graphite anodes ➤ Optional temperature monitoring before and during charge ➤ Proprietary AutoComp charge-rate compensation ➤ Integrated trickle-charge for conditioning deeply discharged batteries ➤ Regulated charge current and voltage ➤ Charge status output for LED or host-processor interface to indicate charge-in-progress, full-capacity, and fault conditions approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass element during the initial stage of charge. ➤ Automatic battery-re-charge feature ➤ Charge termination by minimum current ➤ Direct battery connection ➤ 500mA charge rate ➤ High-side current sensing Once the battery voltage reaches the internal threshold, VMIN, full charge begins. The DV2057/C/T/W complete the charge cycle in two phases. While the pack is below the regulation voltage, a constant-current phase replenishes approximately 70% of battery capacity. An accurate voltage-regulation phase completes the charge. The DV2057/C/T/W terminate charge when the current tapers off to the VTERM threshold. These boards feature the proprietary AutoComp technique to compensate safely for the internal impedance of the battery. The AutoComp resistors, R COMP1 , and RCOMP2, must be set according to the characteristics of the battery. General Description The DV2057/C/T/W are complete development and evaluation environments for bq2057 series advanced Li-Ion linear charge management ICs. The DV2057 family supports both single- and dual-cell Li-Ion packs with coke or graphite anodes: Part Number DV2057 DV2057C DV2057T DV2057W Before using these development boards, please review the bq2057 data sheet. Connection Descriptions Regulation Voltage 4.1V 4.2V 8.2V 8.4V J1 Full charge is preceded by charge qualification based on battery temperature and voltage. The DV2057/C/T/W suspend charge if the battery temperature is outside the VTS1 to VTS2 thresholds and wait until the battery temp e r a t u r e i s w i t h i n t h e a l l o w e d r a n g e. T h e DV2057/C/T/W also check the battery voltage. If the battery voltage is below the low-voltage threshold, VMIN, the DV2057/C/T/W use trickle charge to condition the battery. The conditioning charge rate, I COND, is set at DC+ Charger supply positive DC- Charger supply ground BAT+ Positive battery terminal BAT- Negative battery terminal TEM+ Thermistor connection INH Charge inhibit input J2 J3 SLUU056A - JANUARY 2000 1 DV2057/C/T/W Configuration As configured, charge can be inhibited by connecting the INH input to DC+ or DC–. These boards have the following characteristics: The value of R2 at shipment is 0.2Ω. This resistor can be changed to suit the application. However, the maximum power dissipation in Q1 should not exceed the PD rating. (See recommended DC Operating Conditions.) DV2057/C/T/W Regulation Voltages Part Number Regulation Voltage DV2057 DV2057C DV2057T DV2057W Setup Procedure 4.1V 4.2V 8.2V 8.4V ■ Supply connector J1 accepts a maximum of 16VDC (See the limitation on power dissipation below.) ■ Charge begins after application of both of the following: – the battery – supply voltage ■ Temperature sensing: disabled ■ AutoComp: disabled Connect the battery pack to J1. 2. Connect the charging supply to J2. See the bq2057 data sheet for information on configuring the temperature sensing circuit and the AutoComp feature. As shipped the DV2057/C/T/W uses a bipolar transistor (Q1). Optionally, the user may replace Q1 with a P-channel MOSFET. Please refer to the schematic for details. The on-board regulator supplies a charging current of 500mA. This current is controlled by the value of the sense-resistor, R2 in the following equation: ICHG = 1. 0.100 R2 2 DV2057/C/T/W DV2057/C/T/W Schematic J1 1 2 Q1 FZT788B R2 D1 DC+ DC- 0.2 ZHCS1000 J2 BAT+ C2 1µF BAT- 1 2 3 R1 1.0k R4 RCOMP2 1 RCOMP1 2 R3 2K U1A 8 COMP SNS 7 CC BAT 6 VCC 5 VSS STAT TS D2 LED 1 2 3 4 RT1 J3 TEMP+ INH 1.5M bq2057 SOIC C1 0.1 RT2 1.5M U1B 8 COMP SNS 7 CC BAT 6 VCC VSS 5 STAT TS bq2057 TSSOP Notes: 1 As shipped: RCOMP1 = open circuit RCOMP2 = 0Ω 2 Development Board DV2057 DV2057C DV2057T DV2057W 3 For use with a bipolar transistor: (Q1 is FZT788B) R1 = 1.0kΩ R4 = open circuit For use with a MOSFET: (Q1 is BSP171P (Infineon)) R1 = 100Ω R4 = 1.0kΩ 4. ZHCS1000 and FZT788B are made by Zetex, Inc. Part Number bq2057SN or bq2057TS bq2057CSN or bq2057CTS bq2057TSN or bq2057TTS bq2057WSN or bq2057WTS 3 1 2 3 4 2 1 2 DV2057/C/T/W Recommended DC Operating Conditions Symbol Description Minimum Typical Maximum Unit Notes VDC Input DC voltage VBAT +0.5 - 15 V See Note. ICHG Battery charge current - - 500 mA See Note. VTHERM Therm input voltage 0 - VDC V VINH Inhibit input voltage 0 - VDC V 0 See Regulation Voltages Table. VDC V 1.75 W VBAT BAT input voltage PD Power dissipation Note: Power dissipation must not exceed the maximum PD rating. PD = ICHG ∗ (VDC - VBAT) 4 At 40°C ambient temperature 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. 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