UCC3958DP-4

UCC3958 -1/-2/-3/-4 Single Cell Lithium-Ion Battery Protection Circuit PRELIMINARY FEATURES DESCRIPTION • Protects Sensitive Lithium-Ion Cells Form Over Charging and Over Discharging UCC3958 is a monolithic BCMOS lithium-ion battery protection circuit that is designed to enhance the useful operating life of one cell rechargeable battery packs. Cell protection features consist of internally trimmed charge and discharge voltage limits, discharge current limit with a delayed shutdown and an ultra low current sleep mode state when the cell is discharged. Additional features include an on chip MOSFET for reduced external component count and a charge pump for reduced power losses while charging or discharging a low cell voltage battery pack. This protection circuit requires a minimum number of external components and is able to operate and safely shutdown in the presence of a short circuit load. • Dedicated for One Cell Applications • Does Not Require External FETs or Sense Resistors • Internal Precision Trimmed Charge and Discharge Voltage Limits • Extremely Low Power Drain • Low FET Switch Voltage Drop of 150mV Typical for 3A Currents • Short Circuit Current Protection (with User Programmable Delay) • 3A Current Capacity • Thermal Shutdown • User Controlled Enable Pin BLOCK DIAGRAM UDG-98050 6/98 UCC3958 -1/-2/-3/-4 ABSOLUTE MAXIMUM RATINGS Supply Voltage (PACK+ to BNEG) . . . . . . . . . . . . . . . . . . . 7.5V Maximum Continuous Charge Current . . . . . . . . . . . . . . . . . 3A Maximum Charger Voltage (PACK+ to PACK–) . . . . . . . . . . 9V Maximum Reverse Voltage (PACK+ to PACK–) . . . . . . . . . –8V Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . –55°C to +150°C Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages. CONNECTION DIAGRAMS SOIC-16 (Top View) DP Package TSSOP-24 (Top View) PWP Package ELECTRICAL CHARACTERISTICS: Unless otherwise specified, PACK+ = 4V, –20°C < TA < 70°C. All voltages measured with respect to BNEG. TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS State Transition Thresholds NORM to OV (VOV) UCC3958-1 4.15 4.20 4.25 V OV to NORM (VTHI) UCC3958-1 3.85 3.90 3.95 V NORM to OV (VOV) UCC3958-2 4.20 4.25 4.30 V OV to NORM (VTHI) UCC3958-2 3.90 3.95 4.00 V NORM to OV (VOV) UCC3958-3 4.25 4.30 4.35 V OV to NORM (VTHI) UCC3958-3 3.95 4.00 4.05 V NORM to OV (VOV) UCC3958-4 4.30 4.35 4.40 V OV to NORM (VTHI) UCC3958-4 4.00 4.05 4.10 V NORM to UV (VUV) (Note 1) 2.25 2.35 2.45 V 2.55 2.65 2.75 V 7 18 34 msec UV to NORM (VTLO) OV, UV Delay Time (TD) All Dash Numbers 2 UCC3958 -1/-2/-3/-4 ELECTRICAL CHARACTERISTICS: Unless otherwise specified, PACK+ = 4V, –20°C < TA < 70°C. All voltages measured with respect to BNEG. TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS –100 –150 mV BNEG/PACK - SWITCH VBNEG - VPACK NORM, ISWITCH = 2A NORM, ISWITCH = –2A 100 150 mV VPACK+ > VOV, ISWITCH = 20mA to 2A, (OV State) –100 –300 mV VPACK+ = 2.5V, ISWITCH = –20mA to –2A, (UV State) 100 600 mV NORM ISWITCH = 2A 50 75 mΩ NORM ISWITCH = –2A 50 75 mΩ VPACK+ > VOV (OV State) ([VPACK+] – [VPACK–]=6V) 1 20 µA IPACK+ VPACK+ > VUV 7 20 µA IPACK+ In Super Low Power Mode (VPACK+ < VUV) 1 VBAT Minimum Operating Cell Voltage RDSON IBNEG – (Charger Leakage Current in OV) BIAS Current Battery Sample Rate (TS) 1.5 µA 1.5 V 7 12 17 ms 2.75 5.25 7.25 A Short Circuit Protection ITHLD TDLY RRESET CDLY = 0 350 µs CDLY = 100pF (Maximum Recommended Value) 2.5 ms Overcurrent Reset Resistance MΩ 7.5 LPWARN Output 2.65 2.75 V TR LP Warn Threshold CLOAD = 100pF, 10% to 90% of PACK+ 2.55 280 560 ns TF CLOAD = 100pF, 10% to 90% of PACK+ 120 280 ns VHIGH (VPACK+ –VLPWARN) ISINK = 200µA, VUV < VPACK+ < VTLO 0.3 0.4 V VLOW ISOURCE = 200µA, VTLO < VPACK+ < VUV 0.3 0.4 V Measure Delay 6 ms OVUVB Output TR CLOAD = 100pF, Hi Z to 90% of PACK+ 280 560 ns TF CLOAD = 100pF, Hi Z to 10% of PACK+ 140 280 ns VHIGH (VPACK+ – VOVUVB) ISOURCE = 200µA, VPACK+ ≥ VOV 0.3 0.4 V VLOW ISINK = 200µA, VPACK+ ≤ VUV 0.3 0.4 V ZOUT Output Tristated 10 MΩ 18 ms 150 nA Measure Delay CE Input ISINK Note 1: Other threshold voltages are available. 3 UCC3958 -1/-2/-3/-4 PIN DESCRIPTIONS (nominally 2.65V). This pin will stay high until the detected battery voltage goes above VTLO, or UV condition is declared. BNEG: Connect the negative terminal of the battery to these pins. CBPS: This power supply bypass pin is connected to PACK+ through an internal 10k resistor. An external capacitor must be connected between this pin and BNEG. This capacitor functions as temporary charge storage for high current conditions (short circuit). Minimum capacitor value is 0.15µF. This value should be increased if the CDLY cap is used. OVUVB: This pin is an overvoltage/undervoltage condition indicator. Under normal operating conditions this pin is tristated. When an overvoltage (OV) state is detected, this pin is pulled high. When undervoltage (UV) condition is detected, this pin is pulled low. PACK+: Connect to the positive terminal of the battery. This pin is available to the user. CDLY: Delay control pin for the short circuit protection feature. A capacitor connected between this pin and the BNEG pin will increase the time delay for sensing an over current condition. This adjustment may be useful in those applications where high peak load currents may momentarily exceed the protection circuit’s threshold and interruption of the battery current would be undesirable. The nominal delay time is set internally at 350µs PACK-: These pins should be connected to the negative terminal of the battery pack (negative terminal available to the user). The internal FET switch connects this terminal to the BNEG terminal to give the battery pack user appropriate access to the battery. In an overcharged state, only discharge current is permitted. In an overdischarged state, only charge current is permitted. CEB: Chip Enable Bar. This pin is pulled low (wrt BNEG) by a 100nA current source. In order to disable the IC, the user must pull this pin high to PACK+. SUB: Do not connect. These pins must be electrically isolated from all other pins. These pins may be soldered to isolated copper pads for heatsinking. This will improve heat transfer, which may be necessary at high load currents. LPWARN: Low Power Warning Indicator. This pin is forced high when the battery voltage drops below VTLO APPLICATION INFORMATION Battery Voltage Monitoring If the cell voltage exceeds the Over Voltage threshold for two consecutive samples, charging is disabled, however discharge current is still allowed. This feature of the IC is explained further in the section on Controlled Charge/ Discharge Mode. The battery cell voltage is sampled every 12ms by connecting a resistor divider across it and comparing the resulting voltage to a precision internal reference voltage. Under normal conditions (cell voltage is below Over Voltage threshold and above Under Voltage threshold), the UCC3958 consumes approximately 7µA of current and the internal MOSFET is turned on with an RDSON of 50mΩ. The UCC3958 contains an on-chip Charge Pump to ensure that the internal MOSFET gate is driven high for complete turn-on, reducing power losses. The charge pump switches and capacitors are all internal. 0.10 OHMS 0.08 When the cell voltage falls below the Under Voltage threshold for two consecutive samples, the IC disconnects the load from the battery pack and enters a super low power mode (nominally 1µA). The pack will remain in this state until it detects the application of a charger, at which point controlled charging is enabled. The requirement of two consecutive readings below the UV threshold filters out momentary drops in cell voltage due to load transients, preventing nuisance trips. 0.06 0.04 0.02 0.00 2.6 3.0 3.4 3.8 CELL VOLTAGE 4.2 Figure 1. Typical Rdson vs Cell Voltage (DP Package Pin 7 to Pin 10, at 25°C, 1 Amp Load) 4 UCC3958 -1/-2/-3/-4 APPLICATION INFORMATION (continued) larger load capacitors by connecting an external delay capacitor from the CDLY pin to one of the BNEG pins. LEAKAGE CURRENT (uA) 2000 Once an Over Current condition has been declared, the internal MOSFET turns off. The only way to return the pack to normal operation is to remove the load by unplugging the pack from the system. The overcurrent is reset when an internal pull down brings PACK– to within less than 0.05V above BNEG. At this point, the pack returns to its normal state of operation. A capacitor on the CBPS pin provides momentary holdup for the UCC3958 to assure proper operation in the event that a hard short suddenly pulls the cell voltage below the minimum operating voltage. This cap value can be 0.15µF if the optional CDLY capacitor is not used. An internal 10k resistor buffers the bypass capacitor from the Li-Ion cell. 1600 1200 800 400 0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 CHARGER VOLTAGE (V) Figure 2. Typical OV Leakage Current with Runaway Charger at 25°C 3000 Discharge current is continuously monitored via an internal sense resistor. In the event of excessive current, an Over Current condition is declared if the high current state persists for over 350µs. This delay allows for charging of the system bypass capacitors without tripping the overcurrent. A delay of 350µs guarantees that the pack can charge up to 680µF without declaring an Over Current condition. The delay may be extended to charge 2500 OC DELAY TIME (usec) Over Current Monitoring and Protection 2000 1500 1000 500 0 0 20 40 60 80 100 CDLY CAP VALUE (pf) Figure 4. Typical Overcurrent Delay Time vs CDLY System Status Indicators The UCC3958 provides several convenient system monitoring signals. The first one is the Low Power Warning. This output goes high when the cell voltage is less than 300mV above the Under Voltage Threshold. It signals the system that the battery is getting close to its discharge limit. The second monitoring signal is a tri-statable OV/UV output. Under normal operations conditions, this signal is tri-stated. When an Over Voltage condition is declared, the output is pulled high. When an Under Voltage condition is declared, the output is pulled low. This signal is especially useful during test, allowing easy verification of the OV and UV thresholds. These outputs are with respect to BNEG. UDG-98051 Figure 3. State Diagram 5 UCC3958 -1/-2/-3/-4 APPLICATION INFORMATION (continued) Controlled Charge/Discharge Mode MOSFET VOLTAGE DROP (mV) 0.2Amp 1.0Amp 2.0Amp When the chip senses an over-voltage condition, it prevents any additional charging, but allows discharge. This is accomplished by activating a linear control loop which controls the gate of the MOSFET based on the differential voltage across its drain to source terminals. The linear loop attempts to regulate the differential voltage across the MOSFET to 100mV. When a light load is applied to the part, the loop adjusts the impedance of the MOSFET to maintain 100mV across it. As the load increases, the impedance of the MOSFET is decreased to maintain the 100mV control. At heavy loads (still below “over-current” limit level), the loop will not maintain regulation and will drive the gate of the MOSFET to the battery voltage (not the charge-pump output voltage). The MOSFET RDSON in the over-voltage state will be slightly higher than RDSON during normal operation. The voltage drop (and associated power loss) across the internal MOSFET in this mode of operation is lower than the typical solution of two external back-to-back MOSFETs, where the body diode is conducting. 700 600 500 400 300 200 100 0 2.00 2.10 2.20 2.30 2.40 CELL VOLTAGE (V) Figure 5. Typical MOSFET Voltate Drop During Charge in UV vs. Cell Voltage. UDG-97152 Figure 6. SIngle Cell Lithium-Ion Battery Protector IC Application Diagram 6 UCC3958 -1/-2/-3/-4 APPLICATION INFORMATION (continued) When the chip senses an under-voltage condition, it disconnects the load from the battery pack and shuts itself down to minimize current drain from the battery. Several circuits remain powered and will detect placement of the battery pack into a charger. Once the charger presence is detected, the linear loop is activated and the chip al- lows charging current into the battery. This linear control mode of operation is in effect until the battery voltage reaches a level 300mV above the under-voltage threshold, at which time normal operation is resumed. UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460 7 PACKAGE OPTION ADDENDUM www.ti.com 30-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty UCC3958DP-1 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DP-2 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DP-3 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DP-4 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DPTR-1 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DPTR-2 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DPTR-3 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958DPTR-4 OBSOLETE SOIC D 16 TBD Call TI Call TI UCC3958PWP-1 OBSOLETE TSSOP PW 24 TBD Call TI Call TI UCC3958PWP-2 OBSOLETE TSSOP PW 24 TBD Call TI Call TI UCC3958PWP-3 OBSOLETE TSSOP PW 24 TBD Call TI Call TI Lead/Ball Finish MSL Peak Temp (3) UCC3958PWP-4 OBSOLETE TSSOP PW 24 TBD Call TI Call TI UCC3958PWPTR-1 OBSOLETE HTSSOP PWP 24 TBD Call TI Call TI UCC3958PWPTR-2 OBSOLETE HTSSOP PWP 24 TBD Call TI Call TI UCC3958PWPTR-3 OBSOLETE HTSSOP PWP 24 TBD Call TI Call TI UCC3958PWPTR-4 OBSOLETE HTSSOP PWP 24 TBD Call TI Call TI (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 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. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security Telephony www.ti.com/telephony Video & Imaging www.ti.com/video Wireless www.ti.com/wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright  2005, Texas Instruments Incorporated