! "# User’s Guide December 2001 High Performance Analog Products SLUU107
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use.
EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of 3.0–13.5 V, output of up to 4.2 V and 0.5 A, and maximum power dissipation of 1.0 W. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Contents Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Kit Contents . . . . . . . . . . . . . . . . .
Contents vi
Chapter 1 Introduction This user’s guide describes the bq2420x evaluation module (SLUP141), which conveniently evaluates a charge-management solution for portable applications using the bq2420x product family. This complete, designedand-tested charger delivers up to 500 mA of continuous charge current for single-cell Li-Ion or Li-Pol applications using a current-limited power supply. Topic Page 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background 1.1 Background The bq2420x series are simple Li-Ion linear charge management devices for low-cost and space-limited charger applications. The bq2420x series offer integrated power FET, high-accuracy voltage regulation, temperature monitoring, charge status, and charge termination—all in a single IC. The bq2420x works with a current-limited, wall-mount transformer and therefore does not provide any current regulation.
Kit Contents 1.3 Kit Contents - bq242xx evaluation module (SLUP141) - Set of support documentation 1.4 Performance Specification Summary This section summarizes the performance specifications of the EVM. Table 1–1 gives the performance specifications of the EVM. Table 1–1. Performance Specification Summary Specification Test Conditions Input dc voltage, VDC Min Typ VREG +0.8 0.5 Unit 13.5 V 0.6 Amps Battery charge current, ICHG See Note Battery voltage regulation, VREG Full battery 4.
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Chapter 2 Test Summary This chapter shows the test setups used, and the tests performed, in designing the bq2420xEVM. Topic Page 2.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.2 Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setup 2.1 Setup The BQ2420X EVM board requires a current-limited dc power source to provide input power and a battery-pack charge current. The test setup connections and jumper setting selections are listed in Table 2–1. Table 2–1. I/O and Jumper Connections Jack Connect To: J1–DC+ Power supply positive J1–DC– Power supply ground J2 (Jumper) Normally connected.
Test Procedure 4) Once the battery reaches the voltage limit (4.1 V or 4.2 V), the bq2420x begins the voltage regulation phase of the charge. 5) The battery remains at the fast charge mode until either the charge timer expires or taper current is detected. 6) If the battery discharges down to the recharge threshold, the charger starts fast charging.
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Chapter 3 Schematic, Physical Layouts, and Bill of Materials This chapter contains the bq2420xEVM schematic diagram, board layout, assembly drawings and bill of materials. Topic Page 3.1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3.2 Physical Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic 3.1 Schematic Figure 3–1. bq2420xEVM Schematic Diagram J2 1 J1 D1 DC+ 1 DC– 2 2 U2 bq24200DGN R3 2Ω R8 10 Ω ZHCS1000 C1 0.1 µF R1 1 kΩ R4 1 kΩ Green J4 1 IN OUT 8 4 BAT+ 2 V CC BAT 7 3 BAT– 3 STAT TS 6 2 TS 4 V SS N/C 5 1 BAT– PWP Red C2 0.47 µF 9 R2 1 kΩ CMD67–22SRUGC R5 1 MΩ 1 2 3 J3 LEDs Ext. STAT Jumper 3.2 Physical Layouts 3.2.1 Board Layouts Figure 3–2.
Physical Layouts Figure 3–3. Bottom Layer Figure 3–4.
Bill of Materials 3.3 Bill of Materials This section contains the bill of materials for the SLUP141. Table 3–1 lists materials required for the DM2014H. Table 3–1. Bill of Materials for SLUP141–bq2420xEVM RefDes Count Description Size MFR Part Number Area C1 1 Capacitor, ceramic, 0.1 µF, 16 V, X7R 805 Panasonic ECJ–2VB1C104K 10560 C2 1 Capacitor, ceramic, 0.