1-4 Cell Li+ Battery SMBus Charge Controller datasheet ...

1 Product Sample & Technical Tools & Support &. Folder Buy Documents Software Community bq24725A. SLUSAL0A SEPTEMBER 2011 REVISED AUGUST 2014. bq24725A 1-4 Cell Li+ Battery SMBus Charge Controller with N-Channel Power MOSFET. Selector and Advanced Circuit Protection 1 Features 3 Description 1 SMBus Host-Controlled NMOS-NMOS The bq24725A is a high-efficiency, synchronous Synchronous Buck Converter with Programmable Battery charger, offering low component count for space-constraint, multi-chemistry Battery charging 615kHz, 750kHz, and 885kHz Switching applications. Frequencies Automatic N-channel MOSFET Selection of The bq24725A utilizes two Charge pumps to System Power Source from Adapter or Battery separately drive n-channel MOSFETs (ACFET, RBFET and BATFET) for automatic system power Driven by Internal Charge Pumps source selection.

2 Enhanced Safety Features for Over Voltage Protection, Over Current Protection, Battery , SMBus controlled input current, Charge current, and Inductor and MOSFET Short Circuit Protection Charge voltage DACs allow for very high regulation accuracies that can be easily programmed by the Programmable Input Current, Charge Voltage, system power management micro- Controller . Charge Current Limits The bq24725A uses internal input current register or Charge Voltage Accuracy up to external ILIM pin to throttle down PWM modulation to 3% Charge Current Accuracy up to reduce the Charge current. 3% Input Current Accuracy up to The bq24725A charges one, two, three or four series 2% 20x Adapter Current or Charge Current Li+ cells.

3 Amplifier Output Accuracy Programmable Battery Depletion Threshold, and Device Information(1). Battery LEARN Function PART NUMBER PACKAGE BODY SIZE (NOM). Programmable Adapter Detection and Indicator bq24725A VQFN (20) x Integrated Soft Start (1) For all available packages, see the orderable addendum at the end of the datasheet . Integrated Loop Compensation Real Time System Control on ILIM pin to Limit RAC. Adapter SYS. Charge Current Enhanced Safety: OCP, OVP, FET Short N-FET Driver AC Adapter Operating Range N-FET Driver 5 A Off-State Battery Discharge Current Adapter Detection bq24725A. ( max) Adapter Standby Quiescent Battery SMBus Controls V & I Hybrid Power Pack Current with high accuracy Boost Charge RSR.

4 Controller 1S-4S. 20-pin x mm2 VQFN Package SMBus . HOST. 2 Applications Integration: Loop Compensation; Soft-Start Portable Notebook Computers, UMPC, Ultra-Thin Comparator Notebook, and Netbook Handheld Terminal Industrial and Medical Equipment Portable Equipment 1. An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. bq24725A. SLUSAL0A SEPTEMBER 2011 REVISED AUGUST 2014 Table of Contents 1 Features .. 1 Device Functional 16. 2 Applications .. 1 Register Maps .. 22. 3 Description.

5 1 9 Application and Implementation .. 28. 4 Revision 2 Application 28. Typical Application .. 28. 5 Pin Configuration and Functions .. 3. Application Curves .. 35. 6 4. System Examples .. 35. Absolute Maximum Ratings .. 4. Handling 5 10 Power Supply Recommendations .. 36. Recommended Operating 5 11 37. Thermal Information .. 5 Layout Guidelines .. 37. Electrical 6 Layout Example .. 38. Timing 10 12 Device and Documentation Support .. 39. Typical Characteristics .. 10 Third-Party Products Disclaimer .. 39. 7 Parameter Measurement Information .. 12 Trademarks .. 39. Electrostatic Discharge Caution .. 39. 8 Detailed Description.

6 13. Glossary .. 39. Overview .. 13. Functional Block Diagram .. 14 13 Mechanical, Packaging, and Orderable Feature 15. Information .. 39. 4 Revision History Changes from Original (September 2011) to Revision A Page Changed the format to the new TI standard .. 1. Added the Device Information table .. 1. Added LODRV, HIDRV, and PHASE (2% duty cycle) to the Abs Max Table .. 4. Added the Handling Ratings table .. 5. 2 Submit Documentation Feedback Copyright 2011 2014, Texas Instruments Incorporated Product Folder Links: bq24725A. bq24725A. SLUSAL0A SEPTEMBER 2011 REVISED AUGUST 2014. 5 Pin Configuration and Functions RGR Package Top View PHASE.

7 HIDRV. REGN. BTST. VCC. 20 19 18 17 16. ACN 1 15 LODRV. ACP 2 14 GND. CMSRC 3 bq24725A 13 SRP. ACDRV 4 12 SRN. ACOK 5 11 BATDRV. 6 7 8 9 10. ACDET. IOUT. SDA. ILIM. SCL. Pin Functions PIN. DESCRIPTION. NO. NAME. 1 ACN Input current sense resistor negative input. Place an optional F ceramic capacitor from ACN to GND for common- mode filtering. Place a F ceramic capacitor from ACN to ACP to provide differential mode filtering. 2 ACP Input current sense resistor positive input. Place a F ceramic capacitor from ACP to GND for common-mode filtering. Place a F ceramic capacitor from ACN to ACP to provide differential-mode filtering.

8 3 CMSRC ACDRV Charge pump source input. Place a 4k resistor from CMSRC to the common source of ACFET (Q1) and RBFET (Q2) limits the in-rush current on CMSRC pin. 4 ACDRV Charge pump output to drive both adapter input n-channel MOSFET (ACFET) and reverse blocking n-channel MOSFET. (RBFET). ACDRV voltage is 6V above CMSRC when voltage on ACDET pin is between to , voltage on VCC. pin is above UVLO and voltage on VCC pin is 275mV above voltage on SRN pin so that ACFET and RBFET can be turned on to power the system by AC adapter. Place a 4k resistor from ACDRV to the gate of ACFET and RBFET. limits the in-rush current on ACDRV pin.

9 5 ACOK AC adapter detection open drain output. It is pulled HIGH to external pull-up supply rail by external pull-up resistor when voltage on ACDET pin is between and , and voltage on VCC is above UVLO and voltage on VCC pin is 275mV above voltage on SRN pin, indicating a valid adapter is present to start Charge . If any one of the above conditions can not meet, it is pulled LOW to GND by internal MOSFET. Connect a 10k pull up resistor from ACOK to the pull-up supply rail. 6 ACDET Adapter detection input. Program adapter valid input threshold by connecting a resistor divider from adapter input to ACDET pin to GND pin. When ACDET pin is above and VCC is above UVLO, REGN LDO is present, ACOK.

10 Comparator and IOUT are both active. 7 IOUT Buffered adapter or Charge current output, selectable with SMBus command ChargeOption(). IOUT voltage is 20 times the differential voltage across sense resistor. Place a 100pF or less ceramic decoupling capacitor from IOUT pin to GND. 8 SDA SMBus open-drain data I/O. Connect to SMBus data line from the host Controller or smart Battery . Connect a 10k pull- up resistor according to SMBus specifications. 9 SCL SMBus open-drain clock input. Connect to SMBus clock line from the host Controller or smart Battery . Connect a 10k . pull-up resistor according to SMBus specifications. 10 ILIM Charge current limit input.