INTEGRATED CIRCUITS NE57606 2 to 4 cell redundant Lithium-ion overcharge monitor Product data 2002 Oct 10 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 GENERAL DESCRIPTION The NE57606 is a redundant overcharge detection IC for use within 2-4 cell Li-ion battery packs. It detects the voltage of each Li-ion cell and issues an overcharge signal which then can be used to alert the portable host or be used to turn-off a series charge MOSFET within the battery pack. Its purpose is to act as a back-up protection circuit to a primary Li-ion protection circuits such as the NE57605 and NE57607. The overcharge signal is an open collector output which can be wire-ORed with other safety functions. FEATURES APPLICATIONS • Consumption current (VCEL = 3.8 V) 3.0 µA typical • Consumption current (VCEL = 2.3 V) 0.3 µA typical • Input current between cell pins (VCEL = 3.8 V) ±0.3 µA max • Overcharge detection voltage = threshold voltage ± 50 mV • Overcharge detection delay time (CT = 0.22 µF) 1.5 s typical • Four voltage ranges available • Li-ion Battery pack protection SIMPLIFIED DEVICE DIAGRAM VC4 OV REF VCC VC3 OV REF VC2 OV REF OUT VC1 OV REF 0.7 V GND CT SL01558 Voltage options The device has 4 voltage options. Part Number Detection voltage Hysteresis NE57606Y 4.350 V 250 mV NE57606C 4.225 V None NE57606D 4.130 V None NE57606E 4.450 V 100 mV 2002 Oct 10 2 853-2296 27198 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 ORDERING INFORMATION PACKAGE TYPE NUMBER NAME DESCRIPTION TEMPERATURE RANGE NE57606YD SO8 Small outline plastic, surface mount 8-pin –20 to +80 °C NE57606CD SO8 Small outline plastic, surface mount 8-pin –20 to +80 °C NE57606DD SO8 Small outline plastic, surface mount 8-pin –20 to +80 °C NE57606ED SO8 Small outline plastic, surface mount 8-pin –20 to +80 °C PIN CONFIGURATION OUT CT PIN DESCRIPTION 1 8 2 7 VCC VC4 GND 3 6 VC3 VC1 4 5 VC2 SL01559 Pin No Pin Name 1 OUT 2 CT 3 GND Ground pin 4 VC1 Cell 1 power supply 5 VC2 Cell 2 power supply 6 VC3 Cell 3 power supply 7 VC4 Cell 4 power supply 8 VCC Voltage supply to IC Function Reset output pin Delay capacitance pin MAXIMUM RATINGS Parameter Symbol Min Max Unit VCC VCC input voltage –0.3 +24 V VC2 V4 input voltage (Note1) –0.3 +24 V VC3 V3 input voltage (Note1) –0.3 +24 V VC4 V2 input voltage (Note1) –0.3 +24 V VC1 V1 input voltage (Note1) –0.3 +24 V VCT CT pin voltage –0.3 +24 VOUT VOUT pin voltage –0.3 +24 TSTG Storage Temperature –40 +125 Tamb Operating temperature –20 +80 °C 300 mW Pd Power dissipation NOTES: 1. VCC = >V4 = > V3 = > V2 = > V1 = > –0.3 2. A current no greater than 100 µA should be passed through pin Ct. 2002 Oct 10 3 °C Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 ELECTRICAL CHARACTERISTICS Tamb = 25°C, VCEL = V4–V3 = V3–V2 = V2–V1 = V1–GND, VCC = 4VCEL, except where noted otherwise Symbol Parameter Conditions Min Typ Max Units I1 Consumption current 1 VCEL = 3.8 V 3.0 6.0 µA I2 Consumption current 2 VCEL = 2.3 V 0.3 0.5 µA I3 Pin I/O current between cells VCEL = 3.8 V (V4, V3, V2, V1 side) ±0.0 ±0.3 µA VS Overcharge detection voltage VCEL = L→H, Ta = –20~+70 °C V NE57606Y 4.30 4.350 4.40 NE57606C 4.175 4.225 4.174 NE57606D 4.080 4.130 4.180 NE57606E 4.400 4.450 4.500 HSY Hysteresis voltage VCEL = L→ H →L 0.20 0.25 0.30 V TPLH Overcharge detection delay time CT = 0.22 µF 1.0 1.5 2.0 S VOL Output voltage L IL = 100 µA 0.4 V ILEAK Output leakage current VCEL = 3.8 V, VOUT = 24 V 0.1 µA 2002 Oct 10 4 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 TECHNICAL DISCUSSION During normal operation of the Li-ion system, the battery charger should be the circuit that terminates the charge. The Lithium-ion protection circuit should never be used for routine termination of the charging function. It should be viewed as a back-up protection system in the event of a charger failure. The redundant overcharge detection IC should disconnect the pack from the charger in the event that both other systems have failed. The NE57606 is typically used in conjunction with a Li-ion protection IC as redundant protection for a 2, 3, or 4-cell lithium-ion battery pack. Lithium-ion cells can present a safety hazard if they become overcharged, therefore careful monitoring of each cell’s operating point is necessary. For very safety-sensitive applications, a back-up protection circuit using a device such as the NE57606 is advisable. The NE57606 monitors each cell within a 2-4 Li-ion cell battery pack. If any cell within the battery pack exceeds the full-charge threshold voltage, the overvoltage fault status output assumes a low state. This output signal should be used to alert other parts of the system that an overcharged state has been reached. This output could also be used to open a MOSFET placed in series with the positive battery terminal to interrupt the charging current from the battery charger. Setting the trip-point voltages are key to the system’s operation. First, the trip point tolerances should not overlap, or the systems will not become active in the proper order over large production. The trip points should be typically set in the following fashion: 1. The battery charger should be set to terminate its charge at a point just below the cell’s full charge voltage (–1%) 2. The Li-ion protection circuit is set to open the series charge MOSFET switch at the rated full charge voltage of any of the cell(s). (±1%) Redundant Protection of a Lithium-ion Battery Pack 3. The redundant overcharge detector is set to issue an alert and/or disconnect a series charge MOSFET switch when any cell voltage exceeds the rated full charge voltage (+1%) Within a typical Li-ion battery system, there are two or three major circuits responsible for the monitoring and maintenance of the Li-ion cells: the Li-ion battery charger, the Li-ion protection circuit, and sometimes the redundant Li-ion overcharge detector. This type of system is called a triple-redundant protected system. If any one of the protection circuits fail, then there will be two other independent systems to assume the protection function. If the product is designed properly, that is, component de-rating, non-cascading failure modes, ESD, packaging, etc, having two or more simultaneous failures within the protection system is virtually impossible. 2002 Oct 10 With trip-points set as described above, the charger will taper its charging current until the charging current falls below a certain current level, after which the charger turns off. Only if the charger does not or cannot terminate the charging, the protection IC will open a series MOSFET switch, thus cutting off any charge current. Lastly, if both the charger and the protection IC were to fail, the NE57606 will open another series MOSFET. 5 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 APPLICATION INFORMATION The NE57606 can be used within 2, 3, or 4-cell battery packs. This can be done by electrically creating a short-circuit across the pins that would have been connected to the ends of the cells. For a 3-cell pack pin VC1 should be connected to ground (pins 3 to 4). All of the combinations are shown in Table 1. 100 Ω V+ 0.1 µF 8 VCC Table 1. 7 1 KΩ VC4 0.1 µF Cells VC1 VC2 VC3 VC4 4-cell VC1 VC2 VC3 VC4 3-cell VC1 VC1 VC2 VC3 2-cell VC1 VC1 VC1 VC2 VC3 1 0.1 µF VC2 VC1 V+ 8 CDLY GND 7 1 kΩ VC4 0.1 µF 1 10 KΩ 2 4 C2 10 KΩ 0.1 µF C1 3 0.22 µF C3 V– NE57606 VC3 5 0.1 µF 100 Ω VCC C3 NE57606 The schematics for a 3-cell and a 4-cell monitoring circuit are shown in Figures 1 and 2 respectively. 0.1 µF 10 KΩ 6 OUT C4 10 kΩ 6 0.1 µF OUT OVERVOLTAGE FAULT (OPEN COLLECTOR) C2 SL01561 VC2 5 10 kΩ Figure 2. 4-cell monitoring circuit VC1 4 0.1 µF C1 CDLY GND 2 3 0.22 µF V– OVERVOLTAGE FAULT (OPEN COLLECTOR) SL01560 Figure 1. 3-cell monitoring circuit 2002 Oct 10 6 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor The circuit in Figure 3 shares the charge MOSFET between the ICs. This is sometimes not acceptable since a failure of the charge MOSFET or its associated drive circuitry can disable protection provided by the second circuit. Using the NE57606 within a Li-ion battery system A Li-ion and Li-polymer 4-cell battery system using the NE57605 and the NE57606 is shown in Figures 3 and 4. DISCHARGE FET 100 Ω 0.1 µF NE57606 CHARGE FET V+ 8 7 VCC 1 kΩ VC4 0.1 µF VC3 1 0.1 µF NE57606 1 kΩ C3 10 kΩ 0.1 µF 0.1 µF 18 11 VC4 SEL 17 VC3 0.1 µF 47 kΩ 20 5 VCC DF 5 10 kΩ 0.1 µF 4 1 CF CDLY GND 2 0.1 µF C1 16 VC2 910 kΩ NE57605 0.1 µF C2 10 kΩ VC1 1 kΩ 10 kΩ CS 3 OUT VC2 0.22 µF C4 10 kΩ 6 330 Ω 330 Ω 1 kΩ 15 0.1 µF VC1 CDLY(UV) CDLY(OV) 3 7 9 GND CON CDLY(OC) 8 13 10 V– SYSTEM GROUND SL01562 Figure 3. Shared charge MOSFET 2002 Oct 10 7 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor DISCHARGE FET NE57606 CHARGE FET 100 Ω 0.1 µF REDUNDANT CHARGE FET V+ 8 7 VCC 1 kΩ VC4 0.1 µF VC3 0.1 µF NE57606 1 C4 10 kΩ 6 330 Ω 330 Ω 1 kΩ C3 10 kΩ 0.1 µF 0.1 µF 18 11 VC4 SEL 17 VC3 0.1 µF 47 kΩ 20 5 VCC DF 5 10 kΩ 0.1 µF 4 CDLY GND 2 0.1 µF C1 16 VC2 10 kΩ 910 kΩ 1 CF 910 kΩ NE57605 0.1 µF C2 10 kΩ VC1 1 kΩ 10 kΩ CS 3 OUT VC2 10 kΩ 1 kΩ 15 0.1 µF VC1 CDLY(UV) CDLY(OV) 3 7 9 GND CON CDLY(OC) 8 13 0.22 µF 10 V– SYSTEM GROUND CHARGE SHUTDOWN SL01862 Figure 4. Double-redundantly protected 4-cell Li-ion battery pack (completely redundant system) also not sharing input noise filter components, the failure of the IC due to an input failure or an open circuit will not affect the protection provided by the other circuit. The circuit in Figure 4 shows how to implement a completely isolated design. None of the components are shared and a failure in any part of one circuit will not affect the operation of the other. By 2002 Oct 10 8 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 PACKING METHOD GUARD BAND TAPE REEL ASSEMBLY TAPE DETAIL COVER TAPE CARRIER TAPE BARCODE LABEL BOX SL01305 2002 Oct 10 9 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 SO8: plastic small outline package; 8 leads; body width 3.9 mm pin 1 index B2 1.73 4.95 4.80 0.51 0.33 0.068 0.189 0.195 0.013 0.020 4.95 4.80 SO8 2002 Oct 10 10 1.27 0.38 0.076 0.050 0.015 0.003 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor REVISION HISTORY Rev Date Description _1 20021010 Product data; initial version. Engineering Change Notice 853-2296 27198 (date: 20021003). 2002 Oct 10 11 NE57606 Philips Semiconductors Product data 2 to 4 cell redundant Lithium-ion overcharge monitor NE57606 Purchase of Philips I2C components conveys a license under the Philips’ I2C patent to use the components in the I2C system provided the system conforms to the I2C specifications defined by Philips. This specification can be ordered using the code 9398 393 40011. Data sheet status Level Data sheet status [1] Product status [2] [3] Definitions I 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. II 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. III 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. Relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). [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. [3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status. 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 in the products—including circuits, standard cells, and/or software—described or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). 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. 2002 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: 10-02 For sales offices addresses send e-mail to: [email protected]. Document order number: 2002 Oct 10 12 9397 750 08992