INTEGRATED CIRCUITS NE57600 One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection Product data File under Integrated Circuits, Standard Analog 2001 Oct 03 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 GENERAL DESCRIPTION The NE57600 series is a family of small, high-precision lithium-ion battery protection devices that provide protection against the damaging effects of overcharging, overdischarging, short circuit, and excessive current consumption such as happens if the consumer uses the battery for an apparatus it was not meant to power. The NE57600 is a single-cell Li-ion protection IC. The NE57600 over and under voltage accuracy is trimmed to within ±25 mV (5%) and is available to match the requirements of all lithium-ion cells manufactured in the market today. FEATURES APPLICATIONS • Trimmed overvoltage trip point to within ±25 mV • Programmable overvoltage trip time delay • Trimmed undervoltage trip point to within ±25 mV • Very Low undervoltage sleep quiescent current 0.05 mA • Discharge overcurrent cutoff • Low operating current (10 mA) • Very small SOT-26A package • Protecting one-cell Li-ion battery packs for mobile phones or palmtop devices SIMPLIFIED SYSTEM DIAGRAM V+ VCC 2 CDLY 3 1 NE57600 + VM Li-ION CELL CHARGER OR LOADER GND 5 DF 6 CF 4 – V– DISCHARGE FET CHARGE FET SL01548 Figure 1. Simplified system diagram. 2001 Oct 03 2 853-2294 27198 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 ORDERING INFORMATION PACKAGE TYPE NUMBER NE57600XD NAME DESCRIPTION TEMPERATURE RANGE SOT-26A small outline plastic surface mount, 6-pin –20 to +70 °C NOTE: The device has ten protection parameter options, indicated by the X on the order code, and defined in the following table. TYPICAL PROTECTION PARAMETERS IN THE NE57600 FAMILY Part Number Overcharge detection voltage (V) Overcharge detection hysteresis voltage (mV) Over-discharge detection voltage (V) Over-discharge resumption voltage (V) Overcurrent detection voltage (mV) NE57600Y 4.200 200 2.3 3.00 200 NE57600D 4.200 200 2.3 3.90 200 NE57600E 4.250 200 2.3 3.00 200 NE57600F 4.250 150 2.4 3.00 150 NE57600C 4.280 200 2.3 2.90 120 NE57600G 4.295 150 2.4 3.00 150 NE57600W 4.300 150 2.4 3.00 150 NE57600H 4.325 200 2.5 3.00 200 NE57600J 4.325 200 2.5 3.00 200 NE57600B 4.350 200 2.4 3.00 200 Part number marking PIN CONFIGURATION Each device is marked with a four letter code. The first three letters designate the product. The fourth letter, represented by “x”, is a date tracking code. Part Number Marking NE57600YD AFAx NE57600BD AFBx NE57600CD AFCx NE57600DD AFDx NE57600ED AFEx VM 1 6 DF VCC 2 5 GND CDLY 3 4 CF SL01549 Figure 2. Pin configuration. PIN DESCRIPTION NE57600FD AFFx PIN SYMBOL DESCRIPTION NE57600GD AFGx 1 VM Monitor pin. Detects overcurrent and the presence of a charger. 2 VCC Positive supply voltage input pin. Connect to positive terminal of the cell. 3 CDLY Charge Time Delay pin. The capacitor connected to this pin sets the delay. 4 CF Charge FET pin. This drives the gate of the charge control N-ch FET. 5 GND Ground pin. Connect to negative terminal of the cell. 6 DF Discharge detection pin. This drives the gate of the discharge N-ch FET. NE57600HD AFHx NE57600WD AFJx NE57600JD AFKx 2001 Oct 03 3 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 MAXIMUM RATINGS SYMBOL PARAMETER MIN. MAX. UNIT –0.3 +18 V VIN Input voltage VCF(max) CF pin voltage – VCC – 28 V VVM(max) VM pin voltage – VCC – 28 V Tamb Operating ambient temperature range –20 +70 °C Tstg Storage temperature –40 +125 °C PD Power dissipation – 200 mW ELECTRICAL CHARACTERISTICS Characteristics measured with Tamb = 25 °C, unless otherwise specified. SYMBOL PARAMETER CONDITIONS Min. Typ. Max. UNIT ICC1 Current consumption 1 VCC = 3.6 V: Set between CF–GND: 910 kΩ connected 10.0 14.0 µA ICC2 Current consumption 2 VCC = 3.6 V: IC only between CF–GND: 910 kΩ connected 6.0 10.0 µA ICC3 Current consumption 3 VCC = 3.6 V: Discharge FET OFF between CF–GND: 910 kΩ not connected TBD TBD µA ICC4 Current consumption 4 VCC = 1.9 V: Discharge FET OFF between CF–GND: 910 kΩ not connected 0.05 0.3 µA ICC5 Current consumption 5 VCC = 4.5 V: Set between CF–BG: 910 kΩ connected 35 60 µA VOV(th) Over-charge voltage Tamb = 0 °C ∼ 50 °C VCC: L → H 4.350 4.375 V VOV(hyst) Over-charge hysteresis VCC: H → L 100 200 300 mV VUV(th) Over-discharge voltage VCC: H → L 2.30 2.40 2.50 V VUV(rel) Release over-discharge mode 2.88 3.00 3.12 V VOC(th) Over-current detect level VVM: L → H 174 200 226 mV Release over-current level VVM: H → L 130 mV Condition of release over-current mode Load condition 50 MΩ 1.3 V VOC(rel) 4.325 VSC Short detect level tDLY(OD) Over-discharge dead time tOC(DT) Over-current dead time VM: 0 V → 0.5 V tDLY(SC) Short detect delay time VM: 0 V → 2 V tOLY(OV) Over-charge dead time CTD = 0.01 µF VGDH DF pin LOW level VCC = 3.6 V IDFH1 DF pin source current 1 VDF = VCC – 1.0 V IDFH2 DF pin source current 2 VDF = VCC – 0.3 V IDFL1 DF pin sink current 1 VVM > 1.0 V; VDF = 1.0 V 50 300 IDFL2 DF pin sink current 2 VVM > 1.0 V; VDF = 0.3 V 30 100 ICF1 CF pin source current 1 VCF = VCC – 1.0 V ICF2 CF pin source current 2 VCF = VCC – 0.3 V VST Start trigger voltage VVM: 0 V → –0.5 V –0.2 VPRO Over-voltage charger protection VCC = 3.6 V, between GND–VM voltage –1.5 VOV OV charge minimum voltage VCC = 0 V; Charger voltage 2001 Oct 03 4 7.0 10.0 15.0 ms 7.0 10.0 15.0 ms 0.02 0.20 ms 50 100 150 ms VCC–0.3 VCC–0.1 VCC V –100 –30 µA –0.40 –0.07 µA µA µA –20 –10 µA –15 –5 µA –0.1 0 V –2.5 –3.0 V 2.0 3.0 V Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 TYPICAL PERFORMANCE CURVES 6.0 5.0 Supply current, Icc (µA) Overcharge dead time (seconds) 10 1 0.1 4.0 3.0 2.0 1.0 0.0 0.01 0.0 0.1 0.01 SL01550 60 Supply current, Icc (µA) VCC: H → L 40 30 20 10 0 2.0 3.0 4.0 5.0 6.0 Supply voltage, VCC (V) SL01551 Figure 4. Supply current versus supply voltage. 2001 Oct 03 4.0 5.0 6.0 Figure 5. Supply current versus supply voltage. external capacitor. 1.0 3.0 SL01552 Figure 3. Over-voltage time delay versus 0.0 2.0 Supply voltage, VCC (V) EXTERNAL CAPACITOR (µF) 50 1.0 1 5 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection TECHNICAL DISCUSSION NE57600 Lithium Cell Operating Characteristics The internal resistance of lithium cells is in the 100 mΩ range, compared to the 5–20 mΩ of the nickel-based batteries. This makes the Lithium-ion and polymer cells better for lower battery current applications (less than 1 ampere) as found in cellular and wireless telephones, palmtop and laptop computers, etc. Lithium Cell Safety Lithium-ion and lithium-polymer cells have a higher energy density than that of nickel-cadmium or nickel metal hydride cells and have a much lighter weight. This makes the lithium cells attractive for use in portable products. However, lithium cells require a protection circuit within the battery pack because certain operating conditions can be hazardous to the battery or the operator, if allowed to continue. The average operating voltage of a lithium-ion or polymer cell is 3.6 V as compared to the 1.2 V of NiCd and NiMH cells. The typical discharge curve for Lithium cell is shown in Figure 6. Lithium cells have a porous carbon or graphite anode where lithium ions can lodge themselves in the pores. The lithium ions are separated, which avoids the hazards of metallic lithium. OPEN-CIRCUIT CELL VOLTAGE (V) If the lithium cell is allowed to become overcharged, metallic lithium plates out onto the surface of the anode and volatile gas is generated within the cell. This creates a rapid-disassembly hazard (the battery ruptures). If the cell is allowed to over-discharge (Vcell less than approximately 2.3 V), then the copper metal from the cathode goes into the electrolyte solution. This shortens the cycle life of the cell, but presents no safety hazard. If the cell experiences excessive charge or discharge currents, as happens if the wrong charger is used, or if the terminals short circuit, the internal series resistance of the cell creates heating and generates the volatile gas which could rupture the battery. The protection circuit continuously monitors the cell voltage for an overcharged condition or an overdischarged condition. It also continuously monitors the output for an overcurrent condition. If any of these conditions are encountered, the protection circuit opens a series MOSFET switch to terminate the abnormal condition. The lithium cell protection circuit is placed within the battery pack very close to the cell. VOV 3.0 VUV 2.0 50 100 NORMALIZED CELL CAPACITY (%) SL01553 Figure 6. Lithium discharge curve. Charging control versus battery protection The battery pack industry does not recommend using the pack’s internal protection circuit to end the charging process. The external battery charger should have a charge termination circuit in it, such as that provided by the SA57611. This provides two levels of overcharge protection, with the primary protection of the external charge control circuit and the backup protection from the battery pack’s protection circuit. The charge termination circuit will be set to stop charging at a level around 50 mV less than the overvoltage threshold voltage of the battery pack’s own protection circuit. 2001 Oct 03 4.0 6 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 Charging Lithium Cells The lithium cells must be charged with a dedicated charging IC such as the NE57600. These dedicated charging ICs perform a current-limited, constant-voltage charge, as shown in Figure 7. CHARGE CURRENT (%C) 1.0 The charger IC begins charging with a current that is typically the rating of the cell (1C) or the milliampere rating of the cell. As the cell approaches its full-charge voltage rating (VOV), the current entering the cell decreases, and the charger IC provides a constant voltage. When the charge current falls below a preset amount, 50 mA for example, the charge is discontinued. If charging is begun below the overdischarged voltage rating of the cell, it is important to slowly raise the cell voltage up to this overdischarged voltage level. This is done by a reconditioning charge. A small amount of current is provided to the cell (50 mA for example), and the cell voltage is allowed a period of time to rise to the overdischarged voltage. If the cell voltage recovers, then a normal charging sequence can begin. If the cell does not reach the overdischarged voltage level, then the cell is too damaged to charge and the charge is discontinued. 0.5 CONSTANT CURRENT CONSTANT VOLTAGE 1.0 2.0 TIME (HOURS) OPEN-CIRCUIT CELL VOLTAGE (V) Vov To take advantage of the larger energy density of lithium cells it is important to allow enough time to completely charge the cell . When the charger switches from constant current to constant voltage charge (Point B, Figure 7) the cell only contains about 80 percent of its full capacity. When the cell is 100 mV less than its full rated charge voltage the capacity contained within the cell is 95 percent. Hence, allowing the cell to slowly complete its charge takes advantage of the larger capacity of the lithium cells. 4.0 Point B 3.0 1.0 2.0 TIME (HOURS) Figure 7. Lithium cell charging curves. 2001 Oct 03 7 SL01554 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection Over-voltage Threshold NE57600 Hysteresis Undervoltage Threshold Over-voltage time delay Cell Voltage Dead Time tDLY(OV) VOLTAGE CF Voltage Over-discharge time delay DF Voltage VM Voltage GND Level Excess Discharge Current Mode Charge Mode Discharge Mode Discharge Mode Excess Discharge Mode Charge Mode SL01555 Figure 8. Timing diagram. 2001 Oct 03 8 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 overcurrent threshold voltage (VOC(TH)), then the discharge MOSFET is turned OFF after a fixed 7–18 ms delay. If short-circuit is placed across the pack’s terminals, then the discharge MOSFET is turned OFF after a 100–300 ms delay to avoid damaging the MOSFETs. APPLICATION INFORMATION The NE57600 drives the series N-Channel MOSFETs to states determined by the cell’s voltage and the battery pack load current. During normal operation, both the discharge and charge MOSFETs are ON, allowing bidirectional current flow. If the battery pack is being charged, and the cell’s voltage exceeds the overvoltage threshold, then the charge MOSFET is turned OFF. The cell’s voltage must fall lower than the overvoltage hysteresis voltage (VOV(Hyst)) before the charge MOSFET is again turned ON. The R-C filter on the VCC pin An R-C filter is needed on the VCC pin, primarily to shield the IC from electrostatic energy and spikes on the terminals of the battery pack. A secondary need is during the occurrence of a short-circuit across the battery pack terminals. Here, the Li-ion cell voltage could collapse and cause the IC to enter an unpowered state. The R-C filter provides power during the first instant of the short circuit, allowing the IC to turn OFF the discharge MOSFET before the IC loses power. The R-C filter also filters any voltage noise caused by noisy load current. The values shown in Figure 9 are adequate for these purposes. If the battery pack is being discharged and the undervoltage threshold (VUV(Th)) is exceeded, then the discharge MOSFET is turned OFF. It will not turn back ON until a charger is applied to the pack’s external terminals AND the cell’s voltage rises above the undervoltage hysteresis voltage (VUV(Hyst)). When the battery pack is being discharged, if the load current causes the voltage across the discharge MOSFET to exceed the VCC VCC VCC OV DEADTIME 2 CONTROL OV REF NE57600 UV REF GND 5 CF 3 CDLY 6 DF CHARGER VCC DETECTOR VM 4 UV DEADTIME 1 CONTROL OC REF SL01556 Figure 9. Functional diagram. V+ 330 Ω VCC 2 CDLY 3 1 NE57600 + VM Li-ION CELL 1.0 µF CHARGER OR LOADER 1.0 µF GND 5 DF 6 CF 4 4.7 kΩ 910 kΩ – V– DISCHARGE FET CHARGE FET Figure 10. Typical application circuit. 2001 Oct 03 9 SL01557 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection FET STATUS FOR NORMAL AND ABNORMAL CONDITIONS Operating Mode and Charging Condition Charge FET (CF) Discharge FET (DF) Normal (charging or discharging) ON ON Overcharge (charging) OFF ON Overcharge (discharging) ON ON Overdischarge (discharging) OFF OFF Overdischarge (charging) ON ON Overcurrent (charging or discharging) OFF OFF Normal mode: Overcharge mode: Overdischarge mode: Overcurrent mode: NE57600 Selecting the Optimum MOSFETs For a single-cell battery pack, a logic-level MOSFET should be used. These MOSFETs have turn-on thresholds of 0.9 V and are considered full-on at 4.5 V VGS. Some problem may be encountered in not having enough gate voltage to fully turn-ON the series MOSFETs over the battery pack entire operating voltage. If one deliberately selects an N-Channel MOSFET with a much greater current rating, a lower RDS(on) over the entire range can be attained. The MOSFETs should have a voltage rating greater than 20 V and should have a high avalanche rating to survive any spikes generated across the battery pack terminals. The current rating of the MOSFETs should be greater than four times the maximum “C-rating” of the cells. The current rating, though, is more defined by the total series resistance of the battery pack. The total resistance of the battery pack is given by Equation 1. Overdischarge detection voltage < battery voltage <overcharge detection voltage Discharge current < overcurrent detection level Battery voltage > overcharge detection voltage Overdischarge detection voltage > battery voltage Discharge current > overcurrent detection level voltage between VM and GND = discharge current × FET ON resistance (discharge or charge FET) Rbat(tot) = RDS(on) + Rcell (Equation 1) The total pack resistance is typically determined by the system requirements. The total pack resistance directly determines how much voltage droop will occur during pulses in load current. Another consideration is the forward-biased safe operating area of the MOSFET. During a short-circuit, the discharge current can easily reach 10–15 times the “C-rating” of the cells. The MOSFET must survive this current prior to the discharge MOSFET can be turned OFF. So having an FBSOA envelope that exceeds 20 amperes for 5 ms would be safe. PACKING METHOD GUARD BAND TAPE REEL ASSEMBLY TAPE DETAIL COVER TAPE CARRIER TAPE BARCODE LABEL BOX SL01305 Figure 11. Tape and reel packing method. 2001 Oct 03 10 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 SOT-26A: plastic small outline package; 6 leads; body width 1.8 mm 6 1.15 1.2 1.0 0.025 0.55 0.41 0.22 0.08 3.00 2.70 1.70 1.50 0.55 0.35 SOT-26A 2001 Oct 03 11 Philips Semiconductors Product data One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection NE57600 Data sheet status Data sheet status [1] Product status [2] Definitions Objective data Development This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. Preliminary data Qualification This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. Product data Production This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Changes will be communicated according to the Customer Product/Process Change Notification (CPCN) procedure SNW-SQ-650A. [1] Please consult the most recently issued data sheet before initiating or completing a design. [2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com. Definitions Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Disclaimers Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Koninklijke Philips Electronics N.V. 2001 All rights reserved. Printed in U.S.A. Contact information For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825 Date of release: 10-01 For sales offices addresses send e-mail to: [email protected]. 2001 Oct 03 Document order number: 12 9397 750 08981