ISL94200 ® Data Sheet July 3, 2008 Multi-Cell Li-ion Battery Pack OCP/Analog Front-End The ISL94200 is an overcurrent protection device and analog front end for a microcontroller in a multi-cell Li-ion battery pack. The ISL94200 supports battery pack configurations consisting of 4-cells to 7-cells in series and 1 or more cells in parallel. The ISL94200 provides integral overcurrent protection circuitry, short circuit protection, an internal 3.3V voltage regulator, cell voltage monitor level shifters, and drive circuitry for external FET devices for control of pack charge and discharge. Selectable overcurrent and short circuit thresholds reside in internal RAM registers. An external microcontroller sets the thresholds by setting register values through an I2C serial interface. Internal registers also contain the detection delays for overcurrent and short circuit conditions. Using an internal analog multiplexer the ISL94200 provides monitoring of each cell voltage plus internal and external temperature by a separate microcontroller with an A/D converter. Software on this microcontroller implements all battery pack control functionality, except for overcurrent and short circuit shutdown. Applications • Battery Backup Systems • E-Bikes • Software Selectable Overcurrent Protection Levels and Variable Protect Detection Times - 4 Discharge Overcurrent Thresholds - 4 Short Crcuit Thresholds - 4 Charge Overcurrent Thresholds - 8 Overcurrent Delay Times (Charge) - 8 Overcurrent Delay Times (Discharge) - 2 Short Circuit Delay Times (Discharge) • Automatic FET Turn-Off On Reaching External (Battery) or Internal (IC) Temperature Limit • Fast Short Circuit Pack Shutdown • Can Use Current Sense Resistor, FET rDS(ON), or Sense FET for Overcurrent Detection • Four Battery-Backed Software Controlled Flags • Allows Three Different FET Controls: - Back-to-Back N-Channel FETs for Charge and Discharge Control - Single N-Channel Discharge FET - Single N-Channel FET for Discharge With Separate Optional (Smaller) Back-to-Back N-Channel FETs for Charge • 10% Accurate 3.3V Voltage Regulator (Minimum 25mA Out With External NPN Transistor Having Current Gain Of 70) • Portable Test Equipment • Medical Systems • Monitored Cell Voltage Output Stable in 100µs • Hybrid Vehicle • Simple I2C Host Interface • Military Electronics • Sleep Operation With Programmable Negative Edge or Positive Edge Wake-Up Ordering Information ISL94200IRZ Features • Integrated Charge/Discharge FET Drive Circuitry With 130µA (Typ) Turn-On Current and 180mA (Typ) Discharge FET Turn-Off Current • Power Tools PART NUMBER (Note) FN6718.0 PART MARKING PACKAGE (Pb-free) 942 00IRTZ 24 Ld 4x4 QFN PKG. DWG. # L24.4x4D • <10µA Sleep Mode • Pb-Free (RoHS compliant) NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL94200 Pinout SCL SDA WKUP RGC RGO TEMP3V ISL94200 (24 LD QFN) TOP VIEW 24 23 22 21 20 19 VCELL6 3 16 VMON VCELL5 4 15 CFET NC 5 14 DFET VCELL4 6 13 CSENSE 7 8 9 10 11 12 DSREF 17 AO DSENSE 2 VSS VC7/VCC VCELL1 18 TEMPI VCELL2 1 VCELL3 NC Functional Diagram SCL SDA I2C I/F VC7/VCC CELL VOLTAGES VCELL6 2 MUX 7 POWER CONTROL VCELL5 REGISTERS OVERCURRENT PROTECTION CIRCUITS (THRESHOLD DETECT AND TIMING) VCELL3 VCELL2 3.3VDC REGULATOR FET CONTROL CIRCUITRY RGC RGO CONTROL LOGIC OSC VCELL1 TEMPERATURE SENSOR, INT/EXT COMPARATOR EXT TEMP ENABLE 2 VMON CFET CSENSE VSS DSREF DSENSE BACKUP SUPPLY DFET VCELL4 WKUP LEVEL SHIFTERS AO TEMPI TEMP3V FN6718.0 July 3, 2008 ISL94200 Pin Descriptions SYMBOL DESCRIPTION VC7/VCC Battery cell 7 voltage input/VCC supply. This pin is used to monitor the voltage of this battery cell externally at pin AO. This pin also provides the operating voltage for the IC circuitry. VCELLN Battery cell N voltage input. This pin is used to monitor the voltage of this battery cell externally at pin AO. VCELLN connects to the positive terminal of CELLN and the negative terminal of CELLN + 1. VSS Ground. This pin connects to the most negative terminal in the battery string. DSREF Discharge current sense reference. This input provides a separate reference point for the charge and discharge current monitoring circuits. WIth a separate reference connection, it is possible to minimize errors that result from voltage drops on the ground lead when the load is drawing large currents. If a separate reference is not necessary, connect this pin to VSS. DSENSE Discharge current sense monitor. This input monitors the discharge current by monitoring a voltage. It can monitor the voltage across a sense resistor, or the voltage across the DFET, or by using a FET with a current sense pin. The voltage on this pin is measured with reference to DSREF. CSENSE Charge current sense monitor. This input monitors the charge current by monitoring a voltage. It can monitor the voltage across a sense resistor, or the voltage across the CFET, or by using a FET with a current sense pin. The voltage on this pin is measured with reference to VSS. DFET Discharge FET control. The ISL94200 controls the gate of a discharge FET through this pin. The power FET is a N-Channel device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller, but the ISL94200 also turns off the FET in the event of an overcurrent or short circuit condition. If the microcontroller detects an undervoltage condition on any of the battery cells, it can turn off the discharge FET by controlling this output with a control bit. CFET Charge FET control. The ISL94200 controls the gate of a charge FET through this pin. The power FET is a N-Channel device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller, but the ISL94200 also turns off the FET in the event of an overcurrent condition. If the microcontroller detects an overvoltage condition on any of the battery cells, it can turn off the FET by controlling this output with a control bit. VMON Discharge load monitoring. In the event of an overcurrent or short circuit condition, the microcontroller can enable an internal resistor that connects between the VMON pin and VSS. When the FETs open because of an overcurrent or short circuit condition and the load remains, the voltage at VMON will be near the VCC voltage. When the load is released, the voltage at VMON drops below a threshold indicating that the overcurrent or short circuit condition is resolved. At this point, the LDFAIL flag is cleared and operation can resume. AO Analog multiplexer output. The analog output pin is used by an external microcontroller to monitor the cell voltages and temperature sensor voltages. The microcontroller selects the specific voltage being applied to the output by writing to a control register. TEMP3V Temperature monitor output control. This pin outputs a voltage to be used in a divider that consists of a fixed resistor and a thermistor. The thermistor is located in close proximity to the cells. The TEMP3V output is connected internally to the RGO voltage through a PMOS switch only during a measurement of the temperature, otherwise the TEMP3V output is off. The TEMP3V output can be turned on continuously with a special control bit. Microcontroller wake up control. The TEMP3V pin is also turned on when any of the DSC, DOC, or COC bits are set. This can be used to wake up a sleeping microcontroller to respond to overcurrent conditions with its own control mechanism. TEMPI Temperature monitor input. This pin inputs the voltage across a thermistor to determine the temperature of the cells. When this input drops below TEMP3V/13, an external over-temperature condition exists. The TEMPI voltage is also fed to the AO output pin through an analog multiplexer so the temperature of the cells can be monitored by the microcontroller. RGO Regulated output voltage. This pin connects to the emitter of an external NPN transistor and works in conjunction with the RGC pin to provides a regulated 3.3V. The voltage at this pin provides feedback for the regulator and power for many of the ISL94200 internal circuits as well as providing the 3.3V output voltage for the microcontroller and other external circuits. RGC Regulated output control. This pin connects to the base of an external NPN transistor and works in conjunction with the RGO pin to provide a regulated 3.3V. The RGC output provides the control signal for the external transistor to provide the 3.3V regulated voltage on the RGO pin. WKUP Wake up Voltage. This input wakes up the part when the voltage crosses a turn-on threshold (wake up is edge triggered). The condition of the pin is reflected in the WKUP bit (The WKUP bit is level sensitive.) WKPOL bit = ”1”: the device wakes up on the rising edge of the WKUP pin. Also, the WKUP bit is HIGH only when the WKUP pin voltage > threshold. WKPOL bit = ”0”, the device wakes up on the falling edge of the WKUP pin. Also, the WKUP bit is HIGH only when the WKUP pin voltage < threshold. SDA Serial Data. This is the bidirectional data line for an I2C interface. SCL Serial Clock. This is the clock input for an I2C communication link. 3 FN6718.0 July 3, 2008 ISL94200 Absolute Maximum Ratings Thermal Information Power Supply Voltage, VCC . . . . . . . . . .VSS - 0.5V to VSS + 36.0V Cell Voltage, VCELL VCELLN - (VCELLN - 1), VCELL1 - VSS. . . . . . . . . . . -0.5V to 5V Terminal Voltage, VTERM1 (SCL, SDA, CSENSE, DSENSE, TEMPI, RGO, AO, TEMP3V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VSS - 0.5 to VRGO + 0.5V Terminal Voltage, VTERM2 (CFET, VMON) . . . . VSS - 22.0V to VCC Terminal Voltage, VTERM3 (WKUP) . . . . . . . . . . . . . . . . . . . . . . . . . . . VSS - 0.5V to VCC (VCC <27V) Terminal Voltage, VTERM4 (RGC) . . . . . . . . . . . . . VSS - 0.5V to 5V Terminal Voltage, VTERM5, (all other pins) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VSS - 0.5V to VCC + 0.5V Thermal Resistance (Typical, Notes 1, 2) θJA (°C/W) θJC (°C/W) 24 Ld QFN . . . . . . . . . . . . . . . . . . . . . . 32 2 Continuous Package Power Dissipation . . . . . . . . . . . . . . . . .400mW Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to +125°C Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . .see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp Operating Conditions Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C Supply Voltage Range (Typical). . . . . . . . . . . . . . . . . . . . 5V to 10V Operating Voltage: VCC pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2V to 30.1V VCELL1 - VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3V to 4.3V VCELLN - (VCELLN - 1) . . . . . . . . . . . . . . . . . . . . . . 2.3V to 4.3V CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. NOTES: 1. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech Brief TB379. 2. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside. Operating Specifications Over the recommended operating conditions unless otherwise specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. PARAMETER SYMBOL Operating Voltage TEST CONDITION VCC MIN TYP MAX UNIT 30.1 V 4 9.2 V 1.7 2.3 V 9.2 Power-Up Condition 1 VPORVCC VCC voltage (Note 3) Power-Up Condition 2 Threshold VPOR123 VCELL1 - VSS and VCELL2 - VCELL1 and VCELL3 - VCELL2 (rising) (Note 3) Power-Up Condition 2 Hysteresis VPORhys VCELL1 - VSS and VCELL2 - VCELL1 and VCELL3 - VCELL2 (falling) (Note 3) 1.1 70 mV 3.3V Regulated Voltage VRGO 0µA < IRGC < 350µA 3.0 3.3 3.6 V 3.3VDC Voltage Regulator Control Current Limit IRGC (Control current at output of RGC. Recommend NPN with gain of 70+) 0.35 0.50 VCC Supply Current IVCC1 Power-up defaults, WKUP pin = 0V. 400 510 µA RGO Supply Current IRGO1 Power-up defaults, WKUP pin = 0V. 300 410 µA VCC Supply Current IVCC2 LDMONEN bit = 1, VMON floating, CFET = 1, DFET=1, WKPOL bit = 1, VWKUP = 10V, [AO3:AO0] bits = 03H. 500 700 µA RGO Supply Current IRGO2 LDMONEN bit = 1, VMON floating, CFET = 1, DFET=1, WKPOL bit = 1, VWKUP = 10V, [AO3:AO0] bits = 03H. 450 650 µA VCC Supply Current IVCC3 Default register settings, except SLEEP bit = 1. WKUP pin = VCELL1 10 µA RGO Supply Current IRGO3 Default register settings, except SLEEP bit = 1. WKUP pin = VCELL1 1 µA mA VCELL Input Current (VCELL1) IVCELL1 AO3:AO0 bits = 0000H 14 µA VCELL Input Current (VCELLN) IVCELLN AO3:AO0 bits = 0000H 10 µA 4 FN6718.0 July 3, 2008 ISL94200 Operating Specifications Over the recommended operating conditions unless otherwise specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. (Continued) PARAMETER SYMBOL TEST CONDITION MIN TYP MAX UNIT VOCD = 0.10V (OCDV1, OCDV0 = 0, 0) 0.08 0.10 0.12 V VOCD = 0.12V (OCDV1, OCDV0 = 0,1) 0.10 0.12 0.14 V VOCD = 0.14V (OCDV1, OCDV0 = 1,0) 0.12 0.14 0.16 V VOCD = 0.16V (OCDV1, OCDV0 = 1,1) 0.14 0.16 0.18 V VOCC = 0.10V (OCCV1, OCCV0 = 0, 0) -0.12 -0.10 -0.07 V VOCC = 0.12V (OCCV1, OCCV0 = 0,1) -0.14 -0.12 -0.09 V VOCC = 0.14V (OCCV1, OCCV0 = 1,0) -0.16 -0.14 -0.11 V VOCC = 0.16V (OCCV1, OCCV0 = 1,1) -0.18 -0.16 -0.13 V VOC = 0.20V (SCDV1, SCDV0 = 0, 0) 0.15 0.20 0.25 V VOC = 0.35V (SCDV1, SCDV0 = 0,1) 0.30 0.35 0.40 V VOC = 0.65V (SCDV1, SCDV0 = 1, 0) 0.60 0.65 0.70 V VOC = 1.20V (SCDV1, SCDV0 = 1,1) 1.10 1.20 1.30 V LDMONEN bit = “1” 1.1 1.45 1.8 V OVERCURRENT/SHORT CIRCUIT PROTECTION SPECIFICATIONS VOCD Overcurrent Detection Threshold (Discharge) Voltage Relative To DSREF (Default in Boldface) Overcurrent Detection Threshold (Charge) Voltage Relative to DSREF (Default in Boldface) Short Current Detection Threshold Voltage Relative to DSREF (Default in Boldface) Load Monitor Input Threshold (Falling Edge) VOCC VSC VVMON VVMONH LDMONEN bit = “1” Load Monitor Input Threshold (Hysteresis) Load Monitor Current IVMON Short Circuit Time-out tSCD Over Discharge Current Time-out (Default In Boldface) tOCD 5 0.25 mV 20 40 60 µA Short circuit detection delay (SCLONG bit = ‘0’) 90 190 290 µs Short circuit detection delay (SCLONG bit = ‘1’) 5 10 15 ms tOCD = 160ms (OCDT1, OCDT0 = 0, 0 and DTDIV = 0) 80 160 240 ms tOCD = 320ms (OCDT1, OCDT0 = 0, 1 and DTDIV = 0) 160 320 480 ms tOCD = 640ms (OCDT1, OCDT0 = 1, 0 and DTDIV = 0) 320 640 960 ms tOCD = 1280ms (OCDT1, OCDT0 = 1, 1 and DTDIV = 0) 640 1280 1920 ms tOCD = 2.5ms (OCDT1, OCDT0 = 0, 0 and DTDIV = 1) 1.25 2.50 3.75 ms tOCD = 5ms (OCDT1, OCDT0 = 0, 1 and DTDIV = 1) 2.5 5 7.5 ms tOCD = 10ms (OCDT1, OCDT0 = 1, 0 and DTDIV = 1) 5 10 15 ms tOCD = 20ms (OCDT1, OCDT0 = 1, 1 and DTDIV = 1) 10 20 30 ms FN6718.0 July 3, 2008 ISL94200 Operating Specifications Over the recommended operating conditions unless otherwise specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. (Continued) PARAMETER SYMBOL TEST CONDITION MIN TYP MAX UNIT tOCC tOCC = 80ms (OCCT1,OCCT0 = 0, 0 and CTDIV = 0) 40 80 120 ms tOCC = 160ms (OCCT1, OCCT0 = 0, 1 and CTDIV = 0) 80 160 240 ms tOCC = 320ms (OCCT1, OCCT0 = 1, 0 and CTDIV = 0) 160 320 480 ms tOCC = 640ms (OCCT1, OCCT0 = 1, 1 and CTDIV = 0) 320 640 960 ms tOCC = 2.5ms (OCCT1, OCCT0 = 0, 0 and CTDIV = 1) 1.25 2.50 3.75 ms tOCC = 5ms (OCCT1, OCCT0 = 0, 1 and CTDIV = 1) 2.5 5 7.5 ms tOCC = 10ms (OCCT1, OCCT0 = 1, 0 and CTDIV = 1) 5 10 15 ms tOCC = 20ms (OCCT1, OCCT0 = 1, 1 and CTDIV = 1) 10 20 30 ms Over Charge Current Time-out (Default In Boldface) OVER-TEMPERATURE PROTECTION SPECIFICATIONS Internal Temperature Shutdown Threshold TINTSD Internal Temperature Hysteresis THYS Internal Over-temperature Turn On Delay Time tITD External Temperature Output Current IXT External Temperature Limit Threshold TXTF Temperature drop needed to restore operation after over-temperature shutdown. +125 °C +20 °C 128 ms Current output capability at TEMP3V pin 1.2 mA Voltage at VTEMPI; Relative to falling edge V TEMP3V -20 0 +20 mV 60 110 160 mV ------------------------------ 13 External Temperature Limit Hysteresis TXTH Voltage at VTEMPI. External Temperature Monitor Delay tXTD Delay between activating the external sensor and the internal over-temperature detection. 1 ms TEMP3V is ON (3.3V) 5 ms 635 ms External Temperature Autoscan On-Time tXTAON External Temperature Autoscan Off-Time tXTAOFF TEMP3V output is off. ANALOG OUTPUT SPECIFICATIONS Cell Monitor Analog Output Voltage Accuracy VAOC [VCELLN - (VCELLN-1)]/2 - AO -15 Cell Monitor Analog Output External Temperature Accuracy VAOXT External temperature monitoring accuracy. Voltage error at AO when monitoring TEMPI voltage (measured with TEMPI = 1V) -10 Internal Temperature Monitor Output Voltage Slope 6 VINTMON Internal temperature monitor voltage change 4 -3.5 30 mV 10 mV mV/°C FN6718.0 July 3, 2008 ISL94200 Operating Specifications Over the recommended operating conditions unless otherwise specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. (Continued) PARAMETER SYMBOL Internal Temperature Monitor Output TINT25 AO Output Stabilization Time tVSC TEST CONDITION MIN Output at +25°C TYP MAX UNIT 1.31 From SCL falling edge at data bit 0 of command to AO output stable within 0.5% of final value. AO voltage steps from 0V to 2V. (CAO = 10pF) (Note 7) V 0.1 ms 6.5 V WAKE UP/SLEEP SPECIFICATIONS Device WKUP Pin Voltage Threshold VWKUP1 WKUP pin rising edge (WKPOL = 1) (WKUP Pin Active High - Rising Edge) Device wakes up and sets WKUP flag HIGH. Device Wkup Pin Hysteresis (WKUP Pin Active High) 3.5 100 VWKUP1H WKUP pin falling edge hysteresis (WKPOL = 1) sets WKUP flag LOW (does not automatically enter sleep mode) Input Resistance On WKUP RWKUP Device WKUP Pin Active Voltage Threshold (WKUP Pin Active Low Falling Edge) VWKUP2 WKUP pin falling edge (WKPOL = 0) Device wakes up and sets WKUP flag HIGH. Resistance from WKUP pin to VSS (WKPOL = 1) 130 Device Wake-up Delay tWKUP Delay after voltage on WKUP pin crosses the threshold (rising or falling) before activating the WKUP bit. 230 VCELL1 - 2.6 VCELL1 - 2.0 mV 330 kΩ VCELL1 - 1.2 V 200 VWKUP2H WKUP pin rising edge hysteresis (WKPOL = 0) sets WKUP flag LOW (does not automatically enter sleep mode) Device Wkup Pin Hysteresis (WKUP Pin Active Low) 5.0 20 40 mV 60 ms FET CONTROL SPECIFICATIONS (FOR VCELL1, VCELL2, VCELL3 VOLTAGES FROM 2.8V TO 4.3V) Control Outputs Response Time (CFET, DFET) tCO Bit 0 to start of control signal (DFET) Bit 1 to start of control signal (CFET) 1.0 µs CFET Gate Voltage VCFET No load on CFET VCELL3 - 0.5 VCELL3 + 0.1 V DFETGate Voltage VDFET No load on DFET VCELL3 - 0.5 VCELL3 + 0.1 V FET Turn On Current (DFET) IDFON DFET voltage = 0 to VCELL3 -1.5V 80 130 400 µA FET Turn On Current (CFET) ICF(ON) CFET voltage = 0 to VCELL3 - 1.5V 80 200 400 µA FET Turn Off Current (DFET) IDF(OFF) DFET voltage = VDFET to 1V 100 180 DFET Resistance to VSS RDF(OFF) VDFET <1V (When turning off the FET) mA 11 Ω 100 kHz SERIAL INTERFACE CHARACTERISTICS SCL Clock Frequency fSCL Pulse Width Suppression Time at SDA and SCL Inputs tIN Any pulse narrower than the max spec is suppressed. 50 ns SCL Falling Edge to SDA Output Data Valid tAA From SCL falling crossing VIH(min), until SDA exits the VIL(max) to VIH(min) window. 3.5 µs Time the Bus Must Be Free Before Start of New Transmission tBUF SDA crossing VIH(min) during a STOP condition to SDA crossing VIH(min) during the following START condition. 4.7 µs Clock Low Time tLOW Measured at the VIL(max) crossing. 4.7 µs Clock High Time tHIGH Measured at the VIH(min) crossing. 4.0 µs 7 FN6718.0 July 3, 2008 ISL94200 Operating Specifications Over the recommended operating conditions unless otherwise specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. (Continued) PARAMETER SYMBOL TEST CONDITION MIN Start Condition Setup Time tSU:STA SCL rising edge to SDA falling edge. Both crossing the VIH(min) level. 4.7 µs Start Condition Hold Time tHD:STA From SDA falling edge crossing VIL(max) to SCL falling edge crossing VIH(min). 4.0 µs Input Data Setup Time tSU:DAT From SDA exiting the VIL(max) to VIH(min) window to SCL rising edge crossing VIL(min). 250 ns Input Data Hold Time tHD:DAT From SCL falling edge crossing VIH(min) to SDA entering the VIL(max) to VIH(min) window. 300 µs Stop Condition Setup Time tSU:STO From SCL rising edge crossing VIH(min) to SDA rising edge crossing VIL(max). 4.0 µs Stop Condition Hold Time tHD:STO From SDA rising edge to SCL falling edge. Both crossing VIH(min). 4.0 µs 0 ns Data Output Hold Time tDH From SCL falling edge crossing VIL(max) until SDA enters the VIL(max) to VIH(min) window. (Note 4) TYP MAX UNIT SDA and SCL Rise Time tR From VIL(max) to VIH(min). 1000 ns SDA and SCL Fall Time tF From VIH(min) to VIL(max). 300 ns Capacitive Loading Of SDA Or SCL (Note 5) Cb Total on-chip and off-chip 400 pF SDA and SCL Bus Pull-up ResistorOff-Chip (Note 5) ROUT Input Leakage Current (SCL, SDA) ILI Input Buffer Low Voltage (SCL, SDA) VIL Input Buffer High Voltage (SCL, SDA) Output Buffer Low Voltage (SDA) Maximum is determined by tR and tF. For CB = 400pF, max is about 2kΩ ~ 2.5kΩ For CB = 40pF, max is about 15kΩ to 20kΩ 1 kΩ -10 10 µA Voltage relative to VSS of the device. -0.3 VRGO x 0.3 V VIH Voltage relative to VSS of the device. VRGO x 0.7 VRGO + 0.1 V VOL IOL = 1mA 0.4 V SDA and SCL Input Buffer Hysteresis I2CHYST Sleep bit = 0 0.05 * VRGO V (Note 5) NOTES: 3. Power-up of the device requires all VCELL1, VCELL2, VCELL3, and VCC to be above the limits specified. 4. The device provides an internal hold time of at least 300ns for the SDA signal to bridge the unidentified region of the falling edge of SCL. 5. Limits should be considered typical and are not production tested. 6. Typical 5Ω ±2Ω, based on characterization data. 7. Maximum output capacitance = 15pF. 8 FN6718.0 July 3, 2008 ISL94200 Wake-Up Timing (WKPOL = 0) <tWKUP VWKUP2H VWKUP2 <tWKUP WKUP PIN tWKUP tWKUP WKUP BIT Wake up timing (WKPOL = 1) <tWKUP VWKUP1 VWKUP1H WKUP PIN <tWKUP tWKUP tWKUP WKUP BIT Change in Voltage Source, FET Control SCL BIT 3 SDA BIT 2 BIT 1 BIT 0 BIT 1 BIT 0 DATA AO tVSC tCO tCO tVSC tCO DFET CFET 9 FN6718.0 July 3, 2008 ISL94200 Automatic Temperature Scan AUTO TEMP CONTROL (INTERNAL ACTIVATION) 635ms MONITOR TIME = 5ms 3.3V HIGH IMPEDANCE TEMP3V PIN EXTERNAL TEMPERATURE OVER-TEMPERATURE THRESHOLD TMP3V/13 DELAY TIME = 1ms DELAY TIME = 1ms MONITOR TEMP DURING THIS TIME PERIOD XOT BIT FET SHUTDOWN TURN OFF (IF ENABLED) Discharge Overcurrent/Short Circuit Monitor (Assumes DENOCD and DENSCD bits are ‘0’) VSC VOCD VDSENSE tSCD DOC BIT DSC BIT tSCD tOCD ‘1’ ‘0’ ‘1’ ‘0’ 3.3V TEMP3V OUTPUT REGISTER 1 READ REGISTER 1 READ VCELL3 DFET OUTPUT µC TURNS ON DFET 10 FN6718.0 July 3, 2008 ISL94200 Charge Overcurrent Monitor (Assumes DENOCC bit is ‘0’) VCSENSE VOCC tOCC ‘1’ ‘0’ COC BIT 3.3V TEMP3V OUTPUT REGISTER 1 READ 12V CFET OUTPUT µC TURNS ON CFE Serial Interface Timing Diagrams Bus Timing tF tHIGH tLOW tR SCL tSU:STA tSU:DAT tHD:DAT tSU:STO tHD:STA SDA (INPUT TIMING) tAA tBUF tDH SDA (OUTPUT TIMING) Symbol Table WAVEFORM INPUTS OUTPUTS MUST BE STEADY WILL BE STEADY MAY CHANGE FROM LOW TO HIGH WILL CHANGE FROM LOW TO HIGH MAY CHANGE FROM HIGH TO LOW WILL CHANGE FROM HIGH TO LOW 11 WAVEFORM INPUTS OUTPUTS DON’T CARE: CHANGES ALLOWED CHANGING: STATE NOT KNOWN N/A CENTER LINE IS HIGH IMPEDANCE FN6718.0 July 3, 2008 ISL94200 Registers TABLE 1. REGISTERS ADDR REGISTER READ/WRITE 7 6 5 4 3 2 1 0 00H Config/Op Status Read only Reserved Reserved SA Single AFE WKUP WKUP pin Status Reserved Reserved Reserved Reserved 01H Operating Status Read only Reserved Reserved XOT Ext over temp IOT Int over Temp LDFAIL Load Fail (VMON) DSC Short Circuit 02H Not Used Read/Write Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 03H Analog Out Read/Write UFLG1 UFLG0 User Flag 1 User Flag 0 Reserved Reserved AO3 AO2 AO1 AO0 (Note 10) COC DOC Discharge Charge OC OC Analog output select bits 04H FET Control Read/Write SLEEP Force Sleep (Note 11) LDMONEN Turn on VMON connection Reserved Reserved Reserved Reserved CFET Turn on Charge FET (Note 12) DFET Turn on Discharge FET (Note 12) 05H Discharge Set Read/Write (Write only if DISSETEN bit set) DENOCD OCDV1 OCDV0 DENSCD SCDV1 SCDV0 OCDT1 OCDT0 Read/Write (Write only if CHSETEN bit set) DENOCC OCCV1 Turn off automatic OCC control Overcurrent Charge Threshold Voltage 06H Charge Set Turn off automatic OCD control Overcurrent Discharge Threshold Voltage 07H Feature Set Read/Write (Write only if FSETEN bit set) DIS3 ATMPOFF Turn off Disable 3.3V automatic reg. (device external requires temp scan external 3.3V) 08H Write Enable Read/Write FSETEN Enable Feature Set writes 09H:FFH Reserved NA OCCV0 TMP3ON Turn on Temp3V Short Circuit Discharge Turn off Threshold Voltage automatic SCD control Overcurrent Discharge Time-out OCCT1 SCLONG Long Shortcircuit delay CTDIV Divide charge time by 32 DTDIV Divide discharge time by 64 DISXTSD Disable external thermal shutdown DISITSD Disable internal thermal shutdown POR DISWKUP Force POR Disable WKUP pin UFLG3 UFLG2 Reserved CHSETEN DISSETEN User Flag 3 User Flag 2 Enable Enable Charge Set Discharge Set writes writes OCCT0 Overcurrent Charge Time-out Reserved WKPOL Wake Up Polarity Reserved RESERVED NOTES: 8. A “1” written to a control or configuration bit causes the action to be taken. A “1” read from a status bit indicates that the condition exists. 9. “Reserved” indicates that the bit or register is reserved for future expansion. When writing to addresses 2, 3, 4, and 8: write a reserved bit with the value “0”. Do not write to reserved registers at addresses 09H through FFH. Ignore reserved bits that are returned in a read operation. 10. These status bits are automatically cleared when the register is read. All other status bits are cleared when the condition is cleared. 11. This SLEEP bit is cleared on initial power up, by the WKUP pin going high (when WKPOL = ”1”) or by the WKUP pin going low (when WKPOL = ”0”), and by writing a “0” to the location with an I2C command. 12. When the automatic responses are enabled, these bits are automatically reset by hardware when an overcurrent or short circuit condition turns off the FETs. At all other times, an I2C write operation controls the output to the respective FET and a read returns the current state of the FET drive output circuit (though not the actual voltage at the output pin.) 12 FN6718.0 July 3, 2008 ISL94200 Status Registers TABLE 2. CONFIG/OP STATUS REGISTER (ADDR: 00H) BIT FUNCTION DESCRIPTION 7 RESERVED Reserved for future expansion. 6 RESERVED Reserved for future expansion. 5 SA Single AFE Indicates the device is an ISL94200. This bit is set in the chip and cannot be changed. 4 WKUP This bit is set and reset by hardware. Wakeup pin status When ‘WKPOL’ is HIGH: ’WKUP’ HIGH = WKUP pin > Threshold voltage ‘WKUP’ LOW = WKUP pin < Threshold voltage When ‘WKPOL’ is LOW: ’WKUP’ HIGH = WKUP pin < Threshold voltage ‘WKUP’ LOW = WKUP pin > Threshold voltage 3 RESERVED Reserved for future expansion. 2 RESERVED Reserved for future expansion. 1 RESERVED Reserved for future expansion. 0 RESERVED Reserved for future expansion. TABLE 3. OPERATING STATUS REGISTER (ADDR: 01H) BIT FUNCTION DESCRIPTION 7 RESERVED Reserved for future expansion. 6 RESERVED Reserved for future expansion. 5 XOT Ext Over-temp This bit is set to “1” when the external thermistor indicates an over-temperature condition. If the temperature condition has cleared, this bit is reset when the register is read. 4 IOT Int Over-temp This bit is set to “1” when the internal thermistor indicates an over-temperature condition. If the temperature condition has cleared, this bit is reset when the register is read. 3 LDFAIL When the function is enabled, this bit is set to “1” by hardware when a discharge overcurrent or short circuit condition Load Fail (VMON) occurs and the load remains heavy. When the load fail condition is cleared or under a light load, the bit is reset when the register is read. 2 DSC Short Circuit This bit is set by hardware when a short circuit condition occurs during discharge. When the discharge short circuit condition is removed, the bit is reset when the register is read. 1 DOC Discharge OC This bit is set by hardware when an overcurrent condition occurs during discharge. When the discharge overcurrent condition is removed, the bit is reset when the register is read. 0 COC Charge OC This bit is set by hardware when an overcurrent condition occurs during charge. When the charge overcurrent condition is removed, the bit is reset when the register is read. 13 FN6718.0 July 3, 2008 ISL94200 Control Registers TABLE 4. ANALOG OUT CONTROL REGISTER (ADDR: 03H) BITS FUNCTION DESCRIPTION 7 UFLG1 User Flag 1 General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO turns off. 6 UFLG0 User Flag 0 General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO turns off. 5:4 RESERVED Reserved for future expansion BIT 3 AO3 BIT 2 AO2 BIT 1 AO1 BIT 0 AO0 0 0 0 0 No Output (low power state) 0 0 0 1 VCELL1 0 0 1 0 VCELL2 0 0 1 1 VCELL3 0 1 0 0 VCELL4 0 1 0 1 VCELL5 0 1 1 0 VCELL6 0 1 1 1 VCELL7 1 0 0 0 External Temperature 1 0 0 1 Internal Temperature 1 x 1 x RESERVED 1 1 x x RESERVED Configuration Registers The device is configured for specific application requirements using the Configuration Registers. The configuration registers consist of SRAM memory. OUTPUT VOLTAGE This memory is powered by the RGO output. In a sleep condition, an internal switch converts power for the contents of these registers from RGO to the VCELL1 input. TABLE 5. FET CONTROL REGISTER (ADDR: 04H) BIT FUNCTION DESCRIPTION 7 SLEEP Force Sleep Setting this bit to “1” forces the device to go into a sleep condition. This turns off both FET outputs and the voltage regulator. This also resets the CFET, DFET, and CB7ON:CB1ON bits. The SLEEP bit is automatically reset to “0” when the device wakes up. This bit does not reset the AO3:AO0 bits. 6 LDMONEN Turn on VMON connection 5:2 RESERVED 1 CFET Setting this bit to “1” turns on the charge FET. Setting this bit to “0” turns off the charge FET. This bit is automatically reset in the event of a charge overcurrent condition, unless the automatic response is disabled by the DENOCC bit. 0 DFET Setting this bit to “1” turns on the discharge FET. Setting this bit to “0” turns off the discharge FET. This bit is automatically reset in the event of a discharge overcurrent or discharge short circuit condition, unless the automatic response is disabled by the DENOCD or DENSCD bits. 14 Writing a “1” to this bit turns on the VMON circuit. Writing a “0” to this bit turns off the VMON circuit. As such, the microcontroller has full control of the operation of this circuit. Reserved for future expansion. FN6718.0 July 3, 2008 ISL94200 TABLE 6. DISCHARGE SET CONFIGURATION REGISTER (ADDR: 05H) SETTING FUNCTION When set to ‘0’, a discharge overcurrent condition automatically turns off the FETs. When set to ‘1’, a discharge overcurrent condition will not automatically turn off the FETs. In either case, this condition sets the DOC bit, which also turns on the TEMP3V output. Bit 7 DENOCD Turn off automatic OC discharge control BIT 6 OCDV1 BIT 5 OCDV0 0 0 VOCD = 0.10V 0 1 VOCD = 0.12V 1 0 VOCD = 0.14V VOCD = 0.16V 1 1 Bit 4 DENSCD Turn off automatic SC discharge control BIT 3 SCDV1 BIT 2 SCDV0 OVERCURRENT DISCHARGE VOLTAGE THRESHOLD When set to ‘0’, a discharge short circuit condition turns off the FETs. When set to ‘1’, a discharge short circuit condition will not automatically turn off the FETs. In either case, the condition sets the SCD bit, which also turns on the TEMP3V output. SHORT CIRCUIT DISCHARGE VOLTAGE THRESHOLD 0 0 VSCD = 0.20V 0 1 VSCD = 0.35V 1 0 VSCD = 0.65V 1 1 VSCD = 1.20V BIT 1 OCDT1 BIT 0 OCDT0 0 0 tOCD = 160ms (2.5ms if DTDIV = 1) 0 1 tOCD = 320ms (5ms if DTDIV = 1) 1 0 tOCD = 640ms (10ms if DTDIV = 1) 1 1 tOCD = 1280ms (20ms if DTDIV = 1) 15 OVERCURRENT DISCHARGE TIME-OUT FN6718.0 July 3, 2008 ISL94200 TABLE 7. CHARGE/TIME SCALE CONFIG REGISTER (ADDR: 06H) SETTING FUNCTION When set to ‘0’, a charge overcurrent condition automatically turns off the FETs. When set to ‘1’, a charge overcurrent condition will not automatically turn off the FETs. In either case, this condition sets the COC bit, which also turns on the TEMP3V output. Bit 7 DENOCC Turn off automatic OC charge control BIT 6 OCCV1 BIT 5 OCCV0 0 0 VOCD = 0.10V 0 1 VOCD = 0.12V 1 0 VOCD = 0.14V 1 1 VOCD = 0.16V Bit 4 SCLONG Short circuit long delay Bit 3 CTDIV Divide charge time by 32 Bit 2 DTDIV Divide discharge time by 64 BIT 1 OCCT1 BIT 0 OCCT0 0 0 tOCC = 80ms (2.5ms if CTDIV=1) 0 1 tOCC = 160ms (5ms if CTDIV=1) 1 0 tOCC = 320ms (10ms if CTDIV=1) 1 1 tOCC = 640ms (20ms if CTDIV=1) OVERCURRENT CHARGE VOLTAGE THRESHOLD When this bit is set to ‘0’, a short circuit needs to be in effect for 190us before a shutdown begins. When this bit is set to ‘1’, a short circuit needs to be in effect for 10ms before a shutdown begins. When set to “1”, the charge overcurrent delay time is divided by 32. When set to “0”, the charge overcurrent delay time is divided by 1. When set to “1”, the discharge overcurrent delay time is divided by 64. When set to “0”, the discharge overcurrent delay time is divided by 1. OVERCURRENT CHARGE TIME-OUT TABLE 8. FEATURE SET CONFIGURATION REGISTER (ADDR: 07H) BIT FUNCTION DESCRIPTION 7 ATMPOFF When set to ‘1’ this bit disables the automatic temperature scan. When set to ‘0’, the temperature Turn off automatic external temp scan is turned on for 5ms in every 640ms. 6 DIS3 Disable 3.3V regulator Setting this bit to “1” disables the internal 3.3V regulator. Setting this bit to “1” requires that there be an external 3.3V regulator connected to the RGO pin. 5 TMP3ON Turn on Temp 3.3V Setting this bit to “1” turns ON the TEMP3V output to the external temperature sensor. The output will remain on as long as this bit remains “1”. 4 DISXTSD Disable external thermal shutdown Setting this bit to “1” disables the automatic shutdown of the power FETs in response to an external over-temperature condition. While the automatic response is disabled, the XOT flag is set so the microcontroller can initiate a shutdown based on the XOT flag. 3 DISITSD Disable internal thermal shutdown Setting this bit to “1” disables the automatic shutdown of the power FETs in response to an internal over-temperature condition. While the automatic response is disabled, the IOT flag is set so the microcontroller can initiate a shutdown based on the IOT flag. 2 POR Force POR Setting this bit to “1” forces a POR condition. This resets all internal registers to zero. 1 DISWKUP Disable WKUP pin Setting this bit to “1” disables the WKUP pin function. CAUTION: Setting this pin to ‘1’ prevents a wake up condition. If the device then goes to sleep, it cannot be waken without a communication link that resets this bit, or by power cycling the device. 0 WKPOL Wake Up Polarity Setting this bit to “1” sets the device to wake up on a rising edge at the WKUP pin. Setting this bit to “0” sets the device to wake up on a falling edge at the WKUP pin. 16 FN6718.0 July 3, 2008 ISL94200 . TABLE 9. WRITE ENABLE REGISTER (ADDR: 08H) BIT FUNCTION DESCRIPTION 7 FSETEN When set to “1”, allows writes to the Feature Set register. When set to “0”, prevents writes to the Feature Enable discharge set writes Set register (Addr: 07H). Default on initial power up is “0”. 6 CHSETEN Enable charge set writes 5 DISSETEN When set to “1”, allows writes to the Discharge Set register (Addr: 05H). When set to “0”, prevents writes Enable discharge set writes to the Feature Set register. Default on initial power up is “0”. 4 UFLG3 User Flag 3 General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO turns off. 3 UFLG2 User Flag 3 General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO turns off. 2 RESERVED Reserved for future expansion. 1 RESERVED Reserved for future expansion. 0 RESERVED Reserved for future expansion. When set to “1”, allows writes to the Charge Set register. When set to “0”, prevents writes to the Feature Set register (Addr: 06H). Default on initial power up is “0”. Device Description System Power-Up/Power-Down Design Theory Instructed by the microcontroller, the ISL94200 performs cell voltage monitoring operations, overcurrent and short circuit monitoring with automatic pack shutdown using built-in selectable time delays, and automatic turn off of the power FETs in an over-temperature condition. All automatic functions of the ISL94200 can be turned off and the microcontroller can manage the operations through software. Battery Connection The ISL94200 supports packs of 5 to 7 series connected Li-ion cells. Connection guidelines for each cell combination are shown in Figure 1. 7 CELLS 6 CELLS 5 CELLS VCELL7 VCELL7 VCELL7 VCELL6 VCELL6 VCELL6 VCELL5 VCELL5 VCELL5 VCELL4 VCELL4 VCELL4 VCELL3 VCELL3 VCELL3 VCELL2 VCELL2 VCELL2 VCELL1 VCELL1 VCELL1 VSS VSS VSS The ISL94200 powers up when the voltages on VCELL1, VCELL2, VCELL3, and VCC all exceed their POR threshold. At this time, the ISL94200 wakes up and turns on the RGO output. RGO provides a regulated 3.3VDC ±10% voltage at pin RGO. It does this by using a control voltage on the RGC pin to drive an external NPN transistor (see Figure 2.) The transistor should have a beta of at least 70 to provide ample current to the device and external circuits and should have a VCE of greater than 30V (preferably 50V). The voltage at the emitter of the NPN transistor is monitored and regulated to 3.3V by the control signal RGC. RGO also powers most of the ISL94200 internal circuits. A 500Ω resistor is recommended in the collector of the NPN transistor to minimize initial current surge when the regulator turns on. Once powered up, the device remains in a wake up state until put to sleep by the microcontroller (typically when the cells drop too low in voltage) or until the VCELL1, VCELL2, VCELL3, or VCC voltages drop below their POR threshold. VCC 500 RGC RGO 3.3V VSS Note: Multiple cells can be connected in parallel GND FIGURE 1. BATTERY CONNECTION OPTIONS FIGURE 2. VOLTAGE REGULATOR CIRCUITS 17 FN6718.0 July 3, 2008 ISL94200 WKUP Pin Operation There are two ways to design a wake up of the ISL94200. In an active LOW connection (WKPOL = “0” - default), the device wakes up when a charger is connected to the pack. This pulls the WKUP pin low when compared to a reference based on the VCELL1 voltage. In an active HIGH connection (WKPOL = ‘1’) the device wakes up when the WKUP pin is pulled high by a connection through an external switch. ISL94200 WKUP WKUP (STATUS) 5V 230k* WAKE UP CIRCUITS WKPOL (CONTROL) VCELL1 VSS * Internal resistor only connected when WKPOL = 1. In an overcurrent condition, the ISL94200 automatically turns off the voltage on CFET and DFET pins. The DFET output drives the discharge FET gate low, turning off the FET quickly. The CFET output turns off and allows the gate of the charge FET to be pulled low through a resistor. By turning off the FETs the ISL94200 prevents damage to the battery pack caused by excessive current into or out of the cells (as in the case of a faulty charger or short-circuit condition). When the ISL94200 detects a discharge overcurrent condition, both power FETs are turned off and the DOC bit is set. (When the FETs are turned off, the DFET and CFET bits are also reset.) The automatic response to overcurrent during discharge is prevented by setting the DENOCD bit to “1”. The external microcontroller can turn on the FETs at any time to recover from this condition, but it would usually turn on the load monitor function (by setting the LDMONEN bit) and monitor the LDFAIL bit to detect that the overcurrent condition has been removed. When the ISL94200 detects a discharge short circuit condition, both power FETs are turned off and DSC bit is set. (When the FETs are turned off, the DFET and CFET bits are also reset.) The automatic response to short circuit during discharge is prevented by setting the DENSCD bit to “1”. The external microcontroller can turn on the FETs at any time to recover from this condition, but it would usually turn on the load monitor function (by setting the LDMONEN bit) and monitor the LDFAIL bit to detect that the overcurrent condition has been removed. FIGURE 3. WAKE UP CONTROL CIRCUITS Protection Functions In the default recommended condition, the ISL94200 automatically responds to discharge overcurrent, discharge short circuit, charge overcurrent, internal over-temperature, and external over-temperature conditions. The designer can set optional over-ride conditions that allow the response to be dictated by the microcontroller. These are discussed below. OVERCURRENT SAFETY FUNCTIONS The ISL94200 continually monitors the discharge current by monitoring the voltage at the CSENSE and DSENSE pins. If that voltage exceeds a selected value for a time exceeding a selected delay, then the device enters an overcurrent or short circuit protection mode. In these modes, the ISL94200 automatically turns off both power FETs and hence prevents current from flowing through the terminals P+ and P-. The voltage thresholds and the response times of the overcurrent protection circuits are selectable for discharge overcurrent, charge overcurrent, and discharge short circuit conditions. The specific settings are determined by bits in the Discharge Set Configuration Register (ADDR:05H) (refer to Table 6) and the Charge/Time Scale Configuration Scale Register (ADDR:06H) (refer to Table 7). In addition, refer to “Registers” on page 12. 18 When the ISL94200 detects a charge overcurrent condition, both power FETs are turned off and COC bit is set. (When the FETs are turned off, the DFET and CFET bits are also reset.) The automatic response to overcurrent during discharge is prevented by setting the DENOCC bit to “1”. The external microcontroller can turn on the FETs at any time to recover from this condition, but it would usually wait to do this until the cell voltages are not over charged and that the overcurrent condition has been removed. Or, the microcontroller could wait until the pack is removed from the charger and then re-attached. An alternative method of providing the protection function, if desired by the designer, is to turn off the automatic safety response. In this case, the ISL94200 devices still monitor the conditions and set the status bits, but take no action in overcurrent or short circuit conditions. Safety of the pack depends, instead, on the microcontroller to send commands to the ISL94200 to turn off the FETs. To facilitate a microcontroller response to an overcurrent condition, especially if the microcontroller is in a low power state, a charge overcurrent flag (COC), a discharge overcurrent flag (DOC), or the short circuit flag (DSC) being set causes the ISL94200 TEMP3V output to turn on and pull high (see Figure 5). This output can be used as an external interrupt by the microcontroller to wake-up quickly to handle the overcurrent condition. FN6718.0 July 3, 2008 ISL94200 P+ VSS RL combination of the load resistor, an external adjustment resistor (R1), and the internal load monitor resistor form a voltage divider. R1 is chosen so that when the load is released to a sufficient level, the LDFAIL condition is reset. OPEN OVER-TEMPERATURE SAFETY FUNCTIONS P- POWER FETs R1 ISL94200 VMON VREF External Temperature Monitoring The external temperature is monitored by using a voltage divider consisting of a fixed resistor and a thermistor. This divider is powered by the ISL94200 TEMP3V output. This output is normally controlled so it is on for only short periods to minimize current consumption. Without microcontroller intervention, and in the default state, the ISL94200 provides an automatic temperature scan. This scan circuit repeatedly turns on TEMP3V output (and the external temperature monitor) for 5ms out of every 640ms. In this way, the external temperature is monitored even if the microcontroller is asleep. LDFAIL = 1 if VMON >VVMONH = 0 if VMON ℜ≤ VVMON LDMONEN VSS FIGURE 4. LOAD MONITOR CIRCUIT LOAD MONITORING The load monitor function in the ISL94200 (see Figure 4) is used primarily to detect that the load has been removed following an overcurrent or short circuit condition during discharge. This can be used in a control algorithm to prevent the FETs from turning on while the overload or short circuit condition remains. The load monitor can also be used by the microcontroller algorithms after an undervoltage condition on any cells causes the FETs to turn off. Use of the load monitor prevents the FETs from turning on while the load is still present. This minimizes the possible “oscillations” that can occur when a load is applied in a low capacity pack. It can also be part of a system protection mechanism to prevent the load from turning on automatically - i.e. some action must be taken before the pack is again turned on. The load monitor circuit can be turned on or off by the microcontroller. It is normally turned off to minimize current consumption. It must be activated by the external microcontroller for it to operate. The circuit works by internally connecting the VMON pin to VSS through a resistor. The circuit operates shown as in Figure 4. In a typical pack operation, when an overcurrent or short circuit event happens, the DFET turns off, opening the battery circuit to the load. At this time, the RL is small and the load monitor is initially off. In this condition, the voltage at VMON rises to nearly the pack voltage. Once the power FETs turn off, the microcontroller activates the load monitor by setting the LDMONEN bit. This turns on an internal FET that adds a pull down resistor to the load monitor circuit. While still in the overload condition the 19 When the TEMP3V output turns on, the ISL94200 waits 1ms for the temperature reading to stabilize, then compares the external temperature voltage with an internal voltage divider that is set to TEMP3V/13. When the thermistor voltage is below the reference threshold after the delay, an external temperature fail condition exists. To set the external overtemperature limit, set the value of RX resistor to the 12 times the resistance of the thermistor at the over-temp threshold. The TEMP3V output pin also turns on when the microcontroller sets the AO3:AO0 bits to select that the external temperature voltage. This causes the TEMPI voltage to be placed on AO and activates (after 1ms) the over-temperature detection. As long as the AO3:AO0 bits point to the external temperature, the TEMP3V output remains on. Because of the manual scan of the temperature, it may be desired to turn off the automatic scan, although they can be used at the same time without interference. To turn off the automatic scan, set the ATMPOFF bit. The microcontroller can over-ride both the automatic temperature scan and the microcontroller controlled temperature scan by setting the TEMP3ON configuration bit. This turns on the TEMP3V output to keep the temperature control voltage on all the time, for a continuous monitoring of an over-temperature condition. This likely will consume a significant amount of current, so this feature is usually used for special or test purposes. Protection As a default, when the ISL94200 detects an internal or external over-temperature condition, the FETs are turned off, and the IOT bit or XOT bit (respectively) is set. FN6718.0 July 3, 2008 ISL94200 4ms REGISTERS In the event of an automatic over-temperature condition the FETs are held off until the temperature drops back below the temperature recovery threshold. During this temperature shutdown period, the microcontroller can monitor the internal temperature through the analog output pin (AO), but any writes to the CFET or DFET bits are ignored The automatic response to an internal over-temperature is prevented by setting the DISITSD bit to “1”. The automatic response to an external over-temperature is prevented by setting the DISXTSD bit to “1”. In either case, it is important for the microcontroller to monitor the internal and external temperature to protect the pack and the electronics in an over-temperature condition. RGO TO µC DECODE EXT TEMP VSS (ON) MUX AO EXTERNAL TEMP MONITOR XOT TEMPI VSS TEMP FAIL INDICATOR FIGURE 5. EXTERNAL TEMPERATURE MONITORING AND CONTROL SCL SDA I2C LEVEL SHIFT VC7/VCC LEVEL SHIFT VCELL6 LEVEL SHIFT VCELL2 LEVEL SHIFT VCELL1 REGS AO3:AO0 DECODE AO 2 MUX 20 RX 1ms DELAY TEMPERATURE MONITORING A similar operation occurs when monitoring the internal temperature through the AO output, except there is no external “calibration” of the voltage associated with the internal temperature. For the internal temperature monitoring, the voltage at the output is linear with respect to temperature. See “Operating Specifications” for information about the output voltage at +25°C and the output slope relative to temperature on page 6. 12R TEMP3V VOLTAGE MONITORING The voltage representing the external temperature applied at the TEMPI terminal is directed to the AO terminal through a MUX, as selected by the AO control bits (see Figures 5 and 6). The external temperature voltage is not divided by 2 as are the cell voltages. Instead it is a direct reflection of the voltage at the TEMPI pin. TMP3ON AO3:AO0 The ISL94200 devices can be used to externally monitor individual battery cell voltages and temperatures. Each quantity can be monitored at the analog output pin (AO). The desired voltage is selected using the I2C interface and the AO3:AO0 bits. See Figure 6. Since the voltage on each of the Li-ion Cells are normally higher than the regulated supply voltage, and since the voltages on the upper cells is much higher than is tolerated by a microcontroller, it is necessary to both level shift and divide the voltage before it can be monitored by the microcontroller or an external A/D converter. To get into the voltage range required by the external circuits, the voltage level shifter divides the cell voltage by 2 and references it to VSS. Therefore, a Li-ion cell with a voltage of 4.2V becomes a voltage of 2.1V on the AO pin. ATMPOFF R Analog Multiplexer Selection OSC ISL94200 I2C OVERCURRENT PROTECTION CIRCUITS 508ms I2C CHARGE OC DISCHARGE OC DISCHARGE SC Turning off the FETs in the event of an over-temperature condition prevents continued discharge or charge of the cells when they are over heated. VSS EXT TEMP. TEMPI MUX INT TEMP FIGURE 6. ANALOG OUTPUT MONITORING DIAGRAM FN6718.0 July 3, 2008 ISL94200 External VMON/CFET Protection Mechanisms When there is a single charge/discharge path, a blocking diode is recommended in the VMON to P- path in ISL94200 solution. See D1 in Figure 7. This diode is to protect against a negative voltage on the VMON pin that can occur when the FETs are off and the charger connects to the pack. This diode is not needed when there is a separate charge and discharge path, because the voltages on P- (discharge) are likely always positive. The diode also is not needed if the differential between the minimum pack voltage and maximum charger voltage does not exceed 22V. When the pack is designed with a single set of charge/discharge FETs, the ISL94200 CFET pin should be protected in the event of an over-current or short circuit shutdown. When this happens, the FET opens suddenly. The flyback voltage from the motor windings could exceed the maximum input voltage on the CFET pin. So, it is recommended that an additional external series diode be placed between the CFET pin of the ISL94200 and the gate of the Charge FET. See Diode D3 in Figure 7. This will reduce the CFET gate voltage, but not significantly. Finally, to protect the Charge FET itself in the event of a large negative voltage on the Pack- pin, zener diode D4 is added. The large negative voltage can occur when the P- pin goes significantly negative, while the CFET pin is being internally clamped at VSS. The zener voltage of D4 should be less than the VGS(max) specification of the FET. PACK+ PACKD1 VMON 10M ISL94200 D4 1M D3 CFET microcontroller sets the POR bit to force a power on reset, all of the user flags will also be reset. In addition, if the voltage on cell-1 ever drops below the POR voltage, the contents of the user flags (as well as all other register values) could be lost. Serial Interface INTERFACE CONVENTIONS The device supports a bidirectional bus oriented protocol. The protocol defines any device that sends data onto the bus as a transmitter, and the receiving device as the receiver. The device controlling the transfer is called the master and the device being controlled is called the slave. The master always initiates data transfers, and provides the clock for both transmit and receive operations. Therefore, the ISL94200 devices operate as slaves in all applications. When sending or receiving data, the convention is the most significant bit (MSB) is sent first. So, the first address bit sent is Bit 7. CLOCK AND DATA Data states on the SDA line can change only while SCL is LOW. SDA state changes during SCL HIGH are reserved for indicating start and stop conditions. See Figure 8. START CONDITION All commands are preceded by the start condition, which is a HIGH to LOW transition of SDA when SCL is HIGH. The device continuously monitors the SDA and SCL lines for the start condition and will not respond to any command until this condition has been met. See Figure 9. STOP CONDITION All communications must be terminated by a stop condition, which is a LOW to HIGH transition of SDA when SCL is HIGH. The stop condition is also used to place the device into the Standby power mode after a read sequence. A stop condition is only issued after the transmitting device has released the bus. See Figure 9. ACKNOWLEDGE DFET FIGURE 7. USE OF A DIODES FOR PROTECTING THE CFET AND VMON PINS User Flags The ISL94200 contains four flags in the register area that the microcontroller can use for general purpose indicators. These bits are designated UFLG3, UFLG2, UFLG1, and UFLG0. The microcontroller can set or reset these bits by writing into the appropriate register. Acknowledge is a software convention used to indicate successful data transfer. The transmitting device, either master or slave, releases the bus after transmitting eight bits. During the ninth clock cycle, the receiver pulls the SDA line LOW to acknowledge that it received the eight bits of data. See Figure 10. The device responds with an acknowledge after recognition of a start condition and the correct slave byte. If a write operation is selected, the device responds with an acknowledge after the receipt of each subsequent eight bits. The device acknowledges all incoming data and address bytes, except for the slave byte when the contents do not match the device’s internal slave address. The user flag bits are battery backed up, so the contents remain even after exiting a sleep mode. However, if the 21 FN6718.0 July 3, 2008 ISL94200 In the read mode, the device transmits eight bits of data, releases the SDA line, then monitor the line for an acknowledge. If an acknowledge is detected and no stop condition is generated by the master, the device will continues to transmit data. The device terminates further data transmissions if an acknowledge is not detected. The master must then issue a stop condition to return the device to Standby mode and place the device into a known state SCL When receiving data from the master, the value in the data byte is transferred into the register specified by the address byte on the falling edge of the clock following the 8th data bit. After receiving the acknowledge after the data byte, the device automatically increments the address. So, before sending the stop bit, the master may send additional data to the device without re-sending the slave and address bytes. After writing to address 0AH, the address “wraps around” to address 0. Do not continue to write to addresses higher than address 08H, since these addresses access registers that are reserved. Writing to these locations can result in unexpected device operation. DATA STABLE DATA CHANGE SIGNALS FROM THE MASTER SDA DATA STABLE FIGURE 8. VALID DATA CHANGES ON I2C BUS SLAVE BYTE REGISTER ADDRESS . S T O P DATA 0 1 0 1 0 0 0 0 SIGNALS FROM THE SLAVE SDA BUS S T A R T A C K SCL A C K A C K ISL94200: SLAVE BYTE = 50H FIGURE 11. WRITE SEQUENCE SDA Read Operations START STOP FIGURE 9. I2C START AND STOP BITS SCL FROM MASTER 1 8 9 DATA OUTPUT FROM TRANSMITTER DATA OUTPUT FROM RECEIVER START ACKNOWLEDGE FIGURE 10. ACKNOWLEDGE RESPONSE FROM RECEIVER WRITE OPERATIONS For a write operation, the device requires a slave byte and an address byte. The slave byte specifies the particular device on the I2C bus that the master is writing to. The address specifies one of the registers in that device. After receipt of each byte, the device responds with an acknowledge, and awaits the next eight bits from the master. After the acknowledge, following the transfer of data, the master terminates the transfer by generating a stop condition. See Figure 11. 22 Read operations are initiated in the same manner as write operations with the host sending the address where the read is to start (but no data). Then, the host sends an ACK, a repeated start, and the slave byte with the LSB = 1. After the device acknowledges the slave byte, the device sends out one bit of data for each master clock. After the slave sends eight bits to the master, the master sends a NACK (Not acknowledge) to the device, to indicate the data transfer is complete, then the master sends a stop bit. See Figure 12. After sending the eighth data bit to the master, the device automatically increments its internal address pointer. So the master, instead of sending a NACK and the stop bit, can send additional clocks to read the contents of the next register - without sending another slave and address byte. If the last address read or written is known, the master can initiate a current address read. In this case, only the slave byte is sent before data is returned. (See Figure 12.) . Register Protection The Discharge Set, Charge Set, and Feature Set configuration registers are write protected on initial power up. In order to write to these registers it is necessary to set a bit to enable each one. These write enable bits are in the Write Enable register (Address 08H). Write the FSETEN bit (Addr 8:bit 7) to “1” to enable changes to the data in the Feature Set register (Address 7). FN6718.0 July 3, 2008 ISL94200 SIGNALS FROM THE MASTER Random Read SIGNALS FROM THE SLAVE SDA BUS S T A R T SLAVE BYTE S T A R T REGISTER ADDRESS Current Address Read N A C K SLAVE BYTE S T O P A C K A C K A C K N A C K SLAVE BYTE S T O P 0 1 0 1 0 0 0 1 0 1 0 1 0 0 0 1 0 1 0 1 0 0 0 0 S T A R T DATA A C K DATA ISL94200: SLAVE BYTE = 010100xH FIGURE 12. READ SEQUENCE Write the CHSETEN bit (Addr 8:bit 6) to “1” to enable changes to the data in the Feature Set register (Address 6). Write the DISSETEN bit (Addr 8:bit 5) to “1” to enable changes to the data in the Feature Set register (Address 5). The microcontroller can reset these bits back to zero to prevent inadvertent writes that change the operation of the pack. Operation State Machine Figure 13 shows a device state machine which defines how the ISL94200 responds to various conditions. 23 FN6718.0 July 3, 2008 ISL94200 POWER FAILS AND ONE OR MORE OF THE SUPPLIES, VCC, VCELL1, VCELL2, AND VCELL3 DO NOT MEET MINIMUM VOLTAGE REQUIREMENTS POWER DOWN STATE I2C INTERFACE IS DISABLED. BIASING IS DISABLED. ALL REGISTERS SET TO DEFAULT VALUES (ALL “0”) Power is applied and all of the supplies, VCC, VCELL1, VCELL2, and VCELL3 meet minimum voltage requirements POWER UP STATE I2C INTERFACE IS ENABLED. BIASING IS ENABLED. VOLTAGE REGULATOR IS ENABLED. MAIN OPERATING STATE SLEEP STATE VOLTAGE REGULATOR IS ON VOLTAGE REGULATOR IS OFF LOGIC AND REGISTERS ARE POWERED BY RGO BIASING IS OFF SLEEP bit is set to ‘1’ CFET, DFET OUTPUTS ARE OFF. (REQUIRE AN EXTERNAL COMMAND TO TURN ON) CHARGE AND DISCHARGE CURRENT PROTECTION CIRCUITS AND TEMPERATURE PROTECTION CIRCUITS ARE ACTIVE (DEFAULT). OVERCURRENT CONDITIONS FORCE POWER FETS TO TURN OFF. OVER-TEMPERATURE CONDITIONS FORCE POWER FETS OUTPUTS TO TURN OFF. LOGIC AND REGISTERS ARE POWERED BY VCELL1 CFET, DFET OUTPUTS ARE OFF. WKUP goes above or below threshold (edge triggered). Or, SLEEP bit is set to ‘0’ CHARGE AND DISCHARGE CURRENT PROTECTION CIRCUITS ALL OFF. VOLTAGE AND TEMPERATURE MONITORING CIRCUITS ARE OFF. I2C COMMUNICATION IS ACTIVE (IF VCELL1 VOLTAGE IS HIGH ENOUGH TO OPERATE WITH THE EXTERNAL DEVICE.) VOLTAGE AND TEMPERATURE MONITORING CIRCUITS ARE AWAITING EXTERNAL CONTROL. FIGURE 13. DEVICE OPERATION STATE MACHINE 24 FN6718.0 July 3, 2008 ISL94200 Applications Circuits Also, refer to the ISL9208 or ISL9216 application guides for additional circuit design guidelines. The following application circuits are ideas to consider when developing a battery-pack implementation. There are many more ways that the pack can be designed. P+ ISL94200 500 1.8M 0.1µF VC7/VCC 1.2M VCELL6 SCL SDA VCELL5 200k 0.47µF WKUP RGC VCELL4 RGO VCELL3 TEMP3V THERM TEMPI VCELL2 AO 4.7µF VCELL1 VMON 1µF µF VCC RESET GP I/O SCL SDA INT A/D INPUT I/O OPTIONAL LEDS RESISTORS CHRG 100 3.6V CFET MINIMIZE LENGTH DSREF DSENSE DFET VSS CSENSE MAXIMIZE GAUGE SINGLE WIRE INTERFACE NOT NEEDED DURING DISCHARGE 16V (<CFET VGSMAX) PB- FIGURE 14. 7-CELL APPLICATION CIRCUIT INTEGRATED CHARGE/DISCHARGE 25 FN6718.0 July 3, 2008 ISL94200 ISL94200 500 1.8M 0.1µF VC7/VCC 1.2M VCELL6 SCL SDA VCELL5 0.47µF 200k WKUP RGC VCELL4 RGO VCELL3 TEMP3V THERM TEMPI VCELL2 AO 4.7µF VCELL1 1µF µF VCC RESET GP I/O OPTIONAL LEDS RESISTORS SCL SDA INT A/D INPUT I/O VMON CHRG 100 3.6V CFET MINIMIZE LENGTH DSREF DSENSE VSS CSENSE DFET MAXIMIZE GAUGE SINGLE WIRE INTERFACE NOT NEEDED DURING DISCHARGE OPTIONAL 16V OPTIONAL CHG P- B- FIGURE 15. 7-CELL APPLICATION CIRCUIT SEPARATE CHARGE/DISCHARGE 26 FN6718.0 July 3, 2008 ISL94200 ISL94200 825k 0.1µF SW VC7/VCC TRIGGER IN ONE OF THESE LOCATIONS 500 10V VCELL6 SCL SDA VCELL5 WKUP RGC VCELL4 RGO VCELL3 TEMP3V THERM TEMPI VCELL2 AO 4.7µF VCELL1 1µF µF VCC RESET GP I/O SCL SDA INT A/D INPUT I/O VMON MINIMIZE LENGTH OPTIONAL DSENSE DSREF CSENSE DFET VSS CHRG 100 3.6V SINGLE WIRE INTERFACE NOT NEEDED DURING DISCHARGE CFET MAXIMIZE GAUGE OPTIONAL LEDS RESISTORS OPTIONAL 16V CHG P- B- FIGURE 16. 7-CELL APPLICATION CIRCUIT WITH SWITCH WAKE-UP AND SEPARATE CHARGE/DISCHARGE All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 27 FN6718.0 July 3, 2008 ISL94200 Package Outline Drawing L24.4x4D 24 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE Rev 2, 10/06 4X 2.5 4.00 A 20X 0.50 B PIN 1 INDEX AREA PIN #1 CORNER (C 0 . 25) 24 19 1 4.00 18 2 . 50 ± 0 . 15 13 0.15 (4X) 12 7 0.10 M C A B 0 . 07 24X 0 . 23 +- 0 . 05 4 24X 0 . 4 ± 0 . 1 TOP VIEW BOTTOM VIEW SEE DETAIL "X" 0.10 C C 0 . 90 ± 0 . 1 BASE PLANE ( 3 . 8 TYP ) SEATING PLANE 0.08 C SIDE VIEW ( 2 . 50 ) ( 20X 0 . 5 ) C 0 . 2 REF 5 ( 24X 0 . 25 ) 0 . 00 MIN. 0 . 05 MAX. ( 24X 0 . 6 ) DETAIL "X" TYPICAL RECOMMENDED LAND PATTERN NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal ± 0.05 4. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 indentifier may be either a mold or mark feature. 28 FN6718.0 July 3, 2008