STBC21FTR

STBC21 LI+ battery charger with thermal regulation Datasheet − production data Features ■ Programmable charge current up to 1.1 A ■ Floating voltage limitation outside the safety temperature range ■ PSE fully compatible ■ Low battery voltage detection for pre-charge setting ■ Automatic recharge ■ Two charge status output pins ■ Constant current / constant voltage operation ■ No external MOSFET, sense resistors or blocking diode required ■ Reverse current blocking (50 µA max.) ■ Short-circuit protection and thermal shutdown ■ Less than 1 mA supply current in standby mode ■ Reversed battery polarity protection ■ I²C interface for charging parameters programming ■ ESD: HBM ± 2 kV, CDM 500 V on every pin ■ HTSSOP-14 (5 x 4.4 mm) package available ■ -25 °C to 125 °C operative junction temperature HTSSOP-14 (5 x 4.4 mm) Description The STBC21 is a constant current/constant voltage charger for single cell Li-Ion batteries. Most of the charging parameters, including floating voltage, pre-charge and termination current are programmable in NVM memory. While fast charging current is programmed using an external resistor. The constant current process is split into three phases depending on the battery voltage. If the battery voltage is below 3.0 V, the charging current is set to a programmable value below 200 mA. A timeout of 60 minutes is used in this phase to detect faulty batteries. When the battery voltage goes above 3.0 V, the charger June 2012 This is information on a product in full production. moves to the fast-charge procedure with a current programmable by an external resistor up to 1.1 A. When the battery reaches the value of the floating voltage the charger enters “constant voltage” mode. Even in this mode a protection timer is active to avoid risks due to damaged batteries. The charge cycle is automatically terminated when the current flowing to the battery reaches the value programmed in NVM. There is also a programmable lag time after the termination to maximize the battery charge. An internal block regulates the battery floating voltage when its temperature is outside the safety range between 10 °C and 45 °C, (JEITA/PSE regulation). The floating voltage inside the safety range is set, by default, at 4.2 V. If the external power supply is removed, the STBC21 turns off and a 50 µA (max.) current can flow from the battery to the device. The device also has an undervoltage lockout and automatic recharge capability which can be enabled/disabled by setting a bit in NVM. Two separate status pins allow a lot of information to be gotten based also on flashing frequency and duty cycle. The STBC21 also includes a reversed battery polarity protection to prevent damage due to incorrect battery insertion. The package is a HTSSOP-14 (5 x 4.4). Table 1. Device summary Order code Package Packaging STBC21FTR HTSSOP-14 Tape and reel Doc ID 023256 Rev 1 1/54 www.st.com 54 Contents STBC21 Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6 5.1 Operation mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.2 Battery connection detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.3 Start of charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.4 Fast-charge programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5.5 Charge auto-limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5.6 PHC pin functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.7 Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.8 Reversed battery polarity protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.9 Temperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.10 I²C data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.10.1 Sequential registers write: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.10.2 Sequential registers read: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ESD requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Appendix A Register configuration and access mode description . . . . . . . . . . 30 Appendix B Charging parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Appendix C Charging control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Appendix D Temperature thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Appendix E LED configurations diversified for customer (each customer one pattern). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2/54 Doc ID 023256 Rev 1 STBC21 Contents Appendix F LED display modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Appendix G NVM commands register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Appendix H Charger, battery and alarm status registers . . . . . . . . . . . . . . . . . . 47 H.1 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Doc ID 023256 Rev 1 3/54 List of tables STBC21 List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Table 14. Table 15. Table 16. Table 17. Table 18. Table 19. Table 20. Table 21. Table 22. Table 23. Table 24. Table 25. Table 26. Table 27. Table 28. Table 29. Table 30. Table 31. Table 32. Table 33. Table 34. Table 35. Table 36. Table 37. Table 38. Table 39. Table 40. Table 41. Table 42. Table 43. Table 44. Table 45. Table 46. Table 47. Table 48. 4/54 Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 External components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Electrical characteristics (DC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Start of charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Write single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Read single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Configuration registers map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Control registers map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Timer registers summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Timer-2 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Timer-3 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Charging current registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 SET1 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 ISET3 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Constant voltage register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 CV1 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 CV2 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 CV3 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 CV4 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Halving register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 ISET2 (CV1) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 ISET2 (CV2) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 ISET2 (CV3) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 ISET2 (CV4) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Charging control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Auto recharge bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Temperature thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Th-h reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Th reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Tl reg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Hys reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 LED configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 LED display modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 LED frequency register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 LED duty cycle register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Address: 10H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 NVM commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Address: 11H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Address: 12H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Address: 13H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Digital charger status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Address: 14H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Battery temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 HTSSOP-14L (5 x 4.4 mm) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Doc ID 023256 Rev 1 STBC21 List of figures List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Pin connections (top through view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Charging process flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Battery connection detection flowcharts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Temperature ranges compatible with PSE, power safety electrical . . . . . . . . . . . . . . . . . . 18 V-I characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Battery temperature alarm after charging starts (at battery insertion and at recharge) flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Battery temperature alarm during charge flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Temperature detector schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Charging process diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Charging process diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Battery alarm flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Charger alarm flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 LEDs control circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Junction shutdown temperature detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Layout board (top through view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Layout board (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Drawing dimension HTSSOP-14L (5 x 4.4 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Doc ID 023256 Rev 1 5/54 Block diagram 1 STBC21 Block diagram Figure 1. VCC PHC Block diagram PWR BAT BIAS CLAMP BANDGAP PWRSIS VBAT_SNS VCP ISET POWER ICHARGE VFLOAT VCC _ _ EOC VREF + + 115°C/95°C THERMAL OCP + _ RES3 LED1 RES2 I2C RES1 L O G I C NVM 4.23V _ VBAT + 1.0V + _ BAT_LOW + _ FAST_CH 3.0V VBAT _ 3.9V + BAT_OVP LED2 TH_OFF + _ TH_H + _ 0.75V 0.79V/1.002V TH VBAT 2.6V TEMP + _ 0.89V/1.1V TL RECHARGE + _ 1.74V/1.95V + _ POR + _ VCC_OVP TL_OFF + _ BAT_NO + _ VCC 2.128V 9.0V VCC VCC_OK 2.425V 2.8V BAT_HOT VCC + ASD _ + VBAT 0.505V Voff GND AM10414v1 6/54 Doc ID 023256 Rev 1 STBC21 Block diagram Figure 2. Typical application schematic STBC21A VCC VIN BATTERY PACK VBAT_SNS VCC VREF R6 BAT C1 VREF R7 Li+ Protection Circuit C3 R3 RES1 (I2C Clock) R4 RES2 (I2C Data) TEMP TEMP RES3 (Reserved) GND R5 Li-Ion Battery BAT C4 VREF C5 NTC GND RLED1 LED1 D1 RLED2 D2 LED2 ISET R1 PHC VCP VCC R8 R2 C2 TO AC-DC Table 2. AM10434v2 External components Symbol Parameter Min. Typ. Max. Unit 10 µF C1 Ceramic capacitor SMD C2 Ceramic capacitor SMD TBD µF C3 Ceramic capacitor SMD 0.1 µF C4 Ceramic capacitor SMD 10 µF C5 Ceramic capacitor SMD TBD (1) R1 Resistor 10 (2) kΩ R2 Resistor TBD kΩ R3 Resistor 100 kΩ R4 Resistor 0 Ω 1 (1) R5 Resistor R6 Resistor 4.7 kΩ R7 Resistor 4.7 kΩ R8 Resistor TBD (3) TBD RLED1, RLED2 Resistor 90 D1 LED Kingbright L-934HD D2 LED Kingbright L-934GD Ω 1. Time constant R5*C5 must be less than 20 msec. 2. This value refers to a fast-charge current of 100 mA. 3. Time constant must be chosen taking into account compensation loop. Doc ID 023256 Rev 1 7/54 Pin configuration 2 STBC21 Pin configuration Figure 3. Pin connections (top through view) VCC 1 14 LED2 PHC 2 13 LED1 VCP 3 12 ISET VREF 4 11 BAT RES2 5 10 VBAT_SNS RES1 6 9 TEMP GND 7 8 RES3 AM10433v1 Table 3. Pin description Pin n° Symbol 1 VCC Input supply voltage 2 PHC Photo coupler driver 3 VCP Compensation pin 4 VREF Voltage reference for external NTC 5 RES2 I²C bi-directional data - pulled high 6 RES1 I²C clock - pulled high 7 GND Ground pin 8 RES3 Reserved 9 TEMP Input from temperature sensor 10 VBAT_SNS 11 BAT This pin provides an accurate output voltage and the charge current following the charging algorithm. Only 50 µA reverse current can flow into the device when in standby mode 12 ISET Fast-charge current setting 13 LED1 Open drain. See Appendix E & F 14 LED2 Open drain. See Appendix E & F EXPOSED PAD 8/54 Function Battery voltage sensing Not connected Doc ID 023256 Rev 1 STBC21 3 Maximum ratings Maximum ratings Table 4. Absolute maximum ratings Symbol Value Unit Input supply voltage From -0.3 to 10 V Battery voltage From -6.0 to 6.0 V VPHC PHC voltage From -0.3 to 10 V VVCP VCP voltage From -0.3 to 5.5 V VREF REF voltage From -0.3 to 3.6 V From -0.3 to VREF+0.3 V From -0.3 to 3.6 V 1350 mA Electrostatic discharge voltage (according to HBM JESD22-A114D) ±2 kV Electrostatic discharge voltage (according to CDM JESD22-C101C) 500 V VCC VBAT, VBAT_SNS VLV Parameter TEMP, LED1, LED2, ISET VRES RES1, RES2, RES3 IBAT Charging battery current ESD TSTG Storage temperature range –65 to 150 °C TJ Junction temperature range –40 to 125 °C 300 °C Lead (soldering, 10 seconds) temperature Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. All values are referred to GND. Table 5. Symbol RthJA (1) Thermal data Parameter Thermal resistance junction-ambient Value Unit 37.6 (2) ºC/W 1. Evaluated on 1S2P (1 signal, 2 plane layers) board, 4.4 x 5 mm body size, 3.0 x 3.0 mm pad size, 1.5 W applied power. 2. By 0 velocity (linear feet per minute). This value drops to 30.2 °C/W by 500 velocity. Doc ID 023256 Rev 1 9/54 Electrical characteristics 4 STBC21 Electrical characteristics TJ = -25 °C to 85 °C unless otherwise specified. Refer to the typical application circuit. Typical values are referred to TJ = 25 °C. Table 6. Electrical characteristics (DC) Symbol Parameter Conditions Typ. 2.6 VCC VCC_USB Min. Minimum VCC to enable charging without quasi-pulse Max. Unit 9.0 V 4.5 3.0 V 4.25 V Fast charge 3.0 V