SS4036G Two-Cell Li-Ion and Li-Polymer Charge Management IC PRODUCT SUMMARY Charge management for two-cell Li-Ion or Li-Polymer battery packs Individual cell monitoring - avoids over-charging TSSOP-8 small industry-standard package FEATURES Optional external thermistor monitors the pack temperature Conditioning charge for reviving deeply discharged cells Timer function available to limit the charging time Pb-free, RoHS compliant. DESCRIPTION The SS4036G is a charging control IC designed To be safe, charging is suspended if the voltage for battery packs with two cells in series. When of the temperature sense input pin is higher than multiple cells in a battery pack are connected in Min Temp Threshold (VTmin) or lower than series, the weakest cell determines the overall Max Temp Threshold (VTmax). When the battery pack capacity. The SS4036G monitors the voltage temperature of each cell toensure that no cell is overcharged. SS4036G charges the battery in three phases: The pulse width modulation (PWM) output can be pre-charging, constant-current, or constant- used as either a linear or switching charge-control voltage. If the battery voltage is less than 3.1V, circuit. the SS4036G pre-charges the battery with a low The small 8-pin TSSOP package is ideal for compact battery packs used for portable applications. current. After the pre-charging, the SS4036G The SS4036G continuously monitors each cell voltage, cell current and the battery temperature. is within the safe zone, the applies a constant current to the battery. The value of this constant current is determined by the value of the current sense resistor. When Any unspecified condition will stop the charging to the battery voltage is above the threshold, the to protect the battery cells. An external negative- SS4036G begins constant-voltage charging until temperature-coefficient thermistor is used as a the battery is fully charged. The battery is fully sensor to monitor the battery pack temperature. charged when the current drops down to the termination threshold. 1/09/2006 Rev.3.01 www.SiliconStandard.com 1 of 9 SS4036G PIN CONFIGURATION VDD Temp CCTL LED 1 2 3 4 SS4036G 8 7 6 5 GND V2 V1 Isense PIN DESCRIPTION Pin Name Pin No I/O VDD Temp CCTL LED Isense V1 V2 GND 1 2 3 4 5 6 7 8 P A O O A A A G Description Operating voltage input Temperature sense voltage input Charging control (PWM) output Status indication Current sense voltage input Cell 1 voltage (low side) Cell 2 voltage (high side) Ground ABSOLUTE MAXIMUM RATINGS DC Voltage ………… -0.3V to +7.0V I/O Voltage……. (GND-0.3V) TO (VDD+0.3V) Storage Temperature…………. -55°C to +125°C Operating Temperature………. -40°C to +85°C * 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 = 4MHz, unless otherwise specified. Parameter Operating Voltage Operating Current Standby Current Output High Voltage Output Low Voltage Analog Input 1/09/2006 Rev.3.01 Symbol Min. Typ. Max Unit V DD 4.5 5.0 5.5 V IOP - 1.5 2 mA No load, ADC off ISB - - 1 uA No load, ADC off, WDT off, LVR off - V All I/O, I OH = -10mA GND+0.6 V All I/O, IOL=20mA VDD V Temp, Isense, V1, V2 V OH VDD-0.7 - V OL - - Ain GND www.SiliconStandard.com Condition 2 of 9 SS4036G ELECTRICAL CHARACTERISTICS (continued) VDD = 5V, GND = 0V, TA = 25°C, fosc = 4MHz, Rsens=100mΩ, unless otherwise specified. Parameter Symbol Min. Typ. Max Unit Description Voltage Control Precharge Threshold Vlow - 3.10 - V CC/CV Threshold Vcv - 4.15 - V Max Cell Voltage Bad Battery Threshold Vmax - 4.25 - V Switch to CV mode above this value Maximum cell voltage Vbad - 0.5 - V Difference between V1 and V2 Temperature Sensing Low Temp Threshold High Temp Threshold Resume Threshold Precharge Current Charge Current Taper Current Max Charge Time VTlow - 3.03 - V VThigh - 1.53 - V VTrsm - 1.84 V Current Control Ipre Ichg Itaper Tchg - Upper limit of temperature-sense voltage Lower limit of temperature-sense voltage Threshold for resuming charging 20/Rsense - mA 100/Rsense - mA See note 1 below. mA See note 1 below. Fully charged if the taper current is below this value 20/Rsense - Time Control 340 min See note 1 below. Maximum charging time allowed Note 1: The SS4036G monitors charging current by sensing, at the input pin Isense (5), the voltage drop across a sense resistor, Rsense - see the explanation on page 7. 1/09/2006 Rev.3.01 www.SiliconStandard.com 3 of 9 SS4036G FUNCTIONAL DESCRIPTION A well-known Li-Ion charge algorithm is used by the the SS4036G continuously monitors each cell voltage, the SS4036G to control the charging. Figure 1 shows current and the battery temperature. Any unqualified shows the typical charge profile. Figure 2 is the control flow chart. During the process of charging, condition will stop the charging to protect the battery Trickle Charge CC Charge cells. CV Charge Finished PMV PPV PBV ICC PCV Capacity ICV PLV PEV ITC Figure 1. Typical Charge Profile 1/09/2006 Rev.3.01 www.SiliconStandard.com 4 of 9 SS4036G Power On Reset Start Timer Measure V1, V2, I, T No Temperature OK? Vcell, Vpack OK? No Time out? Yes I Regulate Vpack > Vlow ? No Pre-charge Yes I Regulate Vpack > Vcv? No Constant Current Yes V Regulate Constant Voltage I < Itaper ? No Yes Set Charge-Full End of Charge Figure 2. Control Flow Chart 1/09/2006 Rev.3.01 www.SiliconStandard.com 5 of 9 SS4036G VOLTAGE, CURRENT AND TEMPERATURE SENSING VDD RA 6.8kΩ RB 20kΩ 3kΩ R14 51kΩ 103AT THERMISTER R13 51kΩ CELL2 1 2 3 4 VDD TEMP CCTL LED LED GND V2 V1 ISENSE 8 7 6 5 CELL1 51kΩ SS4036G 10kΩ 100mΩ Figure 3. Cell voltage, current sense and temperature sensor Figure 3 shows the cell voltage sense, current sense 1.615 x Rc x Rh sense and temperature detecting circuit. The pack RA = pack voltage is divided by 2 (by using two equal Rc - Rh resistors, R13 and R14). This guarantees that the 5 x Rc x Rh the voltage on the V2 input pin (7) will not exceed RB = VDD. The SS4036G monitors the charge current by 2Rc - 7 Rh measuring at the Isense input pin (5) the voltage drop across a sense resistor, connected between VSS (battery negative) and GND (Charger ground). The value of this resistor should be between 50mΩ and 150mΩ . To detect the temperature, a negative-temperaturecoefficient thermistor is used as a sensor. A 103AT sensor. A 103AT and a voltage divider (resistor RA and RB) are recommended. The resistor values for RA and RB are calculated using the following equations: 1/09/2006 Rev.3.01 Where, VDD is 5V Rc is the cold temperature resistance Rh is the hot temperature resistance RA, RB are in kΩ . Example : For thermistor 103AT, the hot temperature temperature is 55°C and the cold temperature is 5°C, then RA = 6.8kΩ , RB= 20kΩ . The temperature detection can be disabled by connecting the Temp pin (2) to VDD. www.SiliconStandard.com 6 of 9 SS4036G CHARGING CONTROL P-channel MOSFET V+ VB+ 3.3kΩ 1 VDD U? NPN1 10kΩ 1 2 3 4 VDD TEMP CCTL LED GND V2 V1 ISENSE 8 7 6 5 SS4036G 1kΩ CAP Figure 4. Charging Control Figure 4 shows the linear charger circuit using the MOSFET which is working in the active region. This SS4036G. The output of pin CCTL (3) is a pulse- P-channel MOSFET must be chosen carefully to width-modulated (PWM) signal. This signal is handle the required power dissipation. translated to a DC voltage to control the P-channel CHARGING STATUS INDICATION The LED (4) output pin can sink at most 20mA to light up the LED. Table 1 summarizes the operation of this LED pin. Table 1. Charging Status LED pin output High Low 4 Hz square signal Hi-Z 1/09/2006 Rev.3.01 Condition Normal charging Fully charged Bad battery, charging continued Temperature fault, charging suspended www.SiliconStandard.com 7 of 9 SS4036G PHYSICAL DIMENSIONS (units: inches) TSSOP-8 G C1 BA H C F D E Sym bol A B C C1 D E F G H 1/09/2006 Rev.3.01 m in. 6.2 4.2 0.1 2.8 0.05 0.12 Dim ension in m m nom . 0.65 0.50 - www.SiliconStandard.com m ax. 6.6 4.6 0.3 3.3 1.1 0.10 0.22 8 of 9 SS4036G 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. 1/09/2006 Rev.3.01 www.SiliconStandard.com 9 of 9