SS4035G

SS4035G SSC | Alldatasheet

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www.SiliconStandard.com 1 of 11 SS4035G 1/09/2006 Rev.3.01 Two-Cell Li-Ion and Li-Polymer Charge Management IC Charge management for two-cell Li-Ion or Li-Polymer battery packs Individual cell monitoring - avoids over-charging Pin-selectable charging current PRODUCT SUMMARY

FEATURES

Cell-balancing control circuit - maximizes pack useful life Optional external thermistor monitors the pack temperature Conditioning charging for reviving deeply discharged cells Timer function available to limit the charging time Pb-free, RoHS compliant SO-20 package The SS4035G is a charging control IC designed for battery packs with two cells in series. When multiple cells in a battery pack are connected in series, the weakest cell determines the overall pack capacity. The SS4035G has a cell-balance control circuit to solve this problem, and monitors the voltage of each cell to ensure that no cell is over-charged. The pulse width modulation (PWM) output can be used as either a linear or switching charge-control circuit. Three digital input pins determine the charge current. All these features make the charging circuit design easy and flexible. The SS4035G continuously monitors each cell voltage, cell current and the battery temperature. Any unspecified condition will stop the charging to protect the battery cells. An external negative- temperature-coefficient thermistor is used as a sensor to monitor the battery pack temperature. To be safe, charging is suspended if the voltage of the temperature sense input pin is higher than Min Temp Threshold (VTmin) or lower than Max Temp Threshold (VTmax). When the battery temperature is within the safe zone, the SS4035G charges the battery in three phases: pre-charging, constant-current, or constant-voltage. If the voltage of the temperature sense input pin is higher than Low Temp Threshold (Vtlow), or the battery voltage is less than 3.1V, the SS4035G pre-charges the battery with a low current. After the precharging, the SS4035G applies a constant current to the battery. The value of this constant current is determined by the levels of pins S1, S2 and S3 during power up. When the battery voltage is above the threshold, the SS4035G begins constant-voltage charging until the battery is fully charged. The battery is fully charged when the current drops down to the termination threshold. When the cell voltage is higher than the Balancing Threshold (Vbal), the cell balancing circuit is triggered if one cell voltage is higher than the other by more than 0.02V.

DESCRIPTION

www.SiliconStandard.com 2 of 11 SS4035G 1/09/2006 Rev.3.01 PIN DESCRIPTION Pin Name Pin No I/O Description CLED 1 O Charge control LED CFLED 2 O Charge Full control LED TESTIN 3 I Test input TESTOUT 4 O Test output CCTL 5 O Charging Control, PWM output N/C 6 O Not connected RES 7 I Reset GND 8 G Ground T 9 A Temperature-sense voltage input I 10 A Current-sense voltage input V1 11 A Cell 1 voltage (low side) V2 12 A Cell 2 voltage (high side) VDD 13 P Operating voltage input ROSC 14 I Frequency control resistor S3 15 I Selection no.3 AVDD 16 P Operating voltage for analog circuit BA1 17 O Balancing control for cell 1 BA2 18 O Balancing control for cell 2 S1 19 I Selection no.1 S2 20 I Selection no.2 CLED 1 20 S2 CFLED 2 19 S1 TESTIN 3 18 BA2 TESTOUT 4 17 BA1 CCTL 5 16 AVDD N/C 6 15 S3 RES 7 14 ROSC GND 8 13 VDD T 9 12 V2 I 10 11 V1 PIN CONFIGURATION

www.SiliconStandard.com 3 of 11 SS4035G 1/09/2006 Rev.3.01 ABSOLUTE MAXIMUM RATINGS * Stresses beyond those listed as “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied or intended. Exposure to the absolute maximum rating condition for an extended period may affect device reliability.

ELECTRICAL CHARACTERISTICS

VDD = 4.5V – 5.5V, GND = 0V, TA = 25°C,, fosc = 8MHz, unless otherwise specified. Parameter Symbol Min. Typ. Max Unit Condition Operating Voltage V DD 4.5 5.0 5.5 V Operating Current I OP - 1.5 2 mA No load, no ADC Standby Current I SB - - 1 uA No load, no ADC, no WDT, no LVR Input Low Voltage V IL1 GND - 0.2* VDD V All I/O, except RES Input Low Voltage V IL2 GND - 0.15* VDD V RES Input High Voltage V IH1 0.8*V DD - V DD V All I/O, except RES Input High Voltage V IH2 0.85*V DD - V DD V RES Input Leakage Current IIL -1 - 1 uA Input pins, Vin=VDD or GND Output High Voltage V OH V DD-0.7 - - V All I/O, I OH=-10mA Output Low Voltage V OL - - GND +0.6 V All I/O, I OL=20mA Analog Input Ain GND V DD V T, I, V1, V2

www.SiliconStandard.com 4 of 11 SS4035G 1/09/2006 Rev.3.01 ELECTRICAL CHARACTERISTICS (continued) VDD = 5V, GND = 0V, TA = 25°C, fosc = 8MHz, Rsens=100mΩ, unless otherwise specified. Parameter Symbol Min. Typ. Max Unit Description Voltage Control Pre-charge Threshold V low - 3.10 - V CC/CV Threshold Vcv - 4.135 - V Switch to CV mode above this value Maximum Cell Voltage V max - 4.235 - V Balancing Threshold V bal - 4.135 - V Bad Battery Threshold Vbad - 0.5 - V Difference between Cell1 and Cell 2 voltage Temperature Sensing Min Temp Threshold V tun - 4.31 - V Suspend charging if greater than this value Low Temp Threshold VT low - 3.82 - V Precharge if greater than this value High Temp Threshold VT high - 1.90 - V Decrease current if less than this value MaxTemp Threshold VT over - 1.54 - V Suspend charging if less than this value Resume Temp Threshold VTrsm - 2.10 - V After maximum temperature is reached, resume charging if greater than this value. Current Control Precharge Current I pre - 300 - mA Taper Current I taper - 250 - mA Fully charged if the taper current is below this value. Time Control Maximum Charge Time Tchg 340 Min

Figure 1. Typical Charge Profile

Figure 2. Control Flow Chart

RES (7) is the reset control. A low voltage on this pin will reset the device. Connect to VDD if not used. to VDD through an 8.6kΩ resistor. CLED (1) is the "charging" indication output. This pin goes low when the SS4035G is operating. CFLED (2) is the "fully charged" indication output. This pin goes low when the battery is fully charged. Table 1. Current Selection Table

www.SiliconStandard.com 10 of 11 SS4035G 1/09/2006 Rev.3.01 PHYSICAL DIMENSIONS (units: inches) 0.10mm C SEATING PLANE SO-20 H G Θ B A C 1 CE F D min. nom. max. A 0.394 - 0.419 B 0.290 - 0.300 C 0.014 - 0.020 C1 0.480 - 0.520 D 0.092 - 0.104 E - 0.050 - F 0.004 - - G 0.032 - 0.038 H 0.004 - 0.012 Q 0 º - 10 º Dimensions in inches Symbol

Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infringement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. www.SiliconStandard.com 11 of 11 SS4035G 1/09/2006 Rev.3.01