SS6782GNTR

SS6782G Charge Controller for Dual Batteries FEATURES Quick and easy testing for production. Sequential charging control of two NiMH/NiCd Battery Packs. Reliable sequential fast charge control of dual NiMH and/or NiCd Battery Packs, even with a fluctuating charging current. Fast charge termination by: ∆T∆t, -∆V, 0∆V, safety timer, maximum temperature, or maximum voltage. Linearly adjustable safety timer and ∆T∆t detection slope line. Selectable battery voltage protection range. Selectable battery temperature protection mode. Protection against battery voltage and battery temperature faults. Selectable LED display mode for battery status. Five pulsed trickle charge modes. Discharge-before-charge function available to eliminate memory effect. Choice of 20-pin DIP or 20-pin SOP packages. DESCRIPTION The SS6782G fast-charge controller is designed for intelligent sequential charging of dual NiMH and NiCd batteries without the risk of malfunction. After powering on, the SS6782G charging sequence gives priority to battery pack A, represented by input signals at the ATS and ABV pins, over battery pack B, represented by BTS and BBV pin signals. The SS6782G automatically switches to charging the standby battery pack after the battery pack being charged finishes charging or encounters a fault condition. -∆ V (-0.25%) detection, 0∆V (peak voltage timer) detection, and ∆T∆t detection are the primary methods employed by the SS6782G to terminate fast charge. The fast charge can also be cut off b y maximum battery voltage and maxi mum battery temperature detection along with t he safety timer to prevent charging under fault conditions of the charging system or the battery itself. Both ∆T∆t and -∆V detection methods have been proved powerful in terminating fast charging for NiMH and NiCd batteries. The SS6782G utilizes the combination of these two methods to make a reliable decision for ending fast charge and to avoid issues c aused by using - ∆ V detection alone under certain conditions. Fig. 1 shows an 80 APPLICATIONS Dual-Battery Fast Chargers for: Mobile Phones. Notebook and Laptop Personal Computers. Portable Power Tools and Toys. Portable Communication Equipments. Portable Video & Stereo Equipments. 1.55 100 Charge Current = 600mA Cell Capacity = 550mA NiMH Battery Cell Voltage (V) 1.45 Temperature (°C) example of a charging curve of a battery charged by a fluctuating current from a NiMH battery charger which uses the SS6782G controller IC to achieve optimal charging. The ∆T∆t or -∆V detection circuitry may be disabled independently for different applications, such as system-integrated chargers, chargers with varying charge current, or battery packs lacking a temperature-sensing thermistor. Cell Voltage 1.35 60 1.25 40 Temperature 1.15 0 10 20 30 40 50 60 20 Charge Time (min.) Fig. 1 Battery charging characteristics from an SS6782G-controlled charger with a fluctuating charging current. 9/21/2005 Rev.3.01 www.SiliconStandard.com 1 of 19 SS6782G The safety timer period, t he m ode of battery temperature protection, battery voltage protection range, the pulsed trickle charge duty cycle, and the LED display mode are all adjustable or selectable. A discharge-before-charge function is included to reduce the memory effect of NiCd batteries without the risk of overdischarging. A test mode is provided for charger manufacturers to dramatically reduce the production test time. TYPICAL APPLICATION CIRCUIT R1 R2 + R27 4.7K R28 R34 1K A1012 Q6 R29 R30 150 220 L1 200µH + D1 1N5821 RS 0.1/2W C11 220µF 4.7K D6 1N4148 R6 R7 + 1N5820 A1012 D4 Q2 R22 470 R23 330 VCC(5V) R21 2.7K Q1 D468 R5 20/5W R32 680 4 THERMISTOR BATTERY B B2 R10 B C5 0.1µF R11 + C6 100µF VCC(5V) 5 C7 0.1µF R13 R12 6 7 R14 8 100K THERMISTOR BATTERY A B1 VCC(5V) R16 9 ATS R15 R17 10 LEA1 680 ICOA LEA2 1N5820 D5 R37 3.9K R35 1.5K Q7 D468 R3 100K C1 4.7µF C2 0.1µF D7 R8 100K C3 4.7µF R4 390 C4 0.1µF VCC 5V 1 ABV DSW ICOB 2 20 SW1 19 R20 680 LED4 1N4148 VIN LED5 + 2.2µF C12 D8 1N4148 1M R36 3 BBV LEB2 18 SS6782G DIS LEB1 17 R19 680 LED3 DC DE CF C10 1nF BOOST IS VCC + VCC(5V) VIN 78L05 C9 100µF R33 47K D2 1N4148 Q3 3904 GND 16 BTS VCC SEL1 15 14 GND FB SS6563G R25 1N4148 D3 470 A1012 Q4 ADJ SEL3 TMR SEL2 R26 330 VCC(5V) R24 2.7K 13 MODE 12 11 R18 LED2 680 Q5 3904 A C8 0.1µF LED1 Battery charger for Dual NiMH and NiCd Batteries 9/21/2005 Rev.3.01 www.SiliconStandard.com 2 of 19 SS6782G ORDERING INFORMATION SS67 82 G XXX P IN CONFIGURATION P acking options TR: t ape and reel (not for PDIP) TB: t ube (only option for PDIP) P ackage type G N: R oHS-compliant PDIP-20 G S: R oHS-compliant S O-20 PIN CONFIGURATION TOP VIEW A BV BBV 1 2 2 0 DSW 19 ICOB 1 8 LEB2 17 LEB1 16 GND 1 5 SEL1 1 4 SEL2 DIS 3 BTS VCC A DJ 4 5 6 SEL3 7 Exa mple: S S6 782 G STR in R oHS-compliant S O -20 , shipped on tape and reel TMR 8 1 3 M ODE 12 ICOA A TS 9 LEA1 10 1 1 LEA2 ABSOLUTE MAXIMUM RATINGS Supply voltage DC voltage applied on any pin Sink current of ICOA pin, LEA1 and LEA2 pins Sink current of ICOB pin, LEB1 and LEB2 pins Operating temperature range Maximum junction temperature Storage temperature range 5.5V 5.5V 20mA 20mA -40°C ~ +85°C 125°C -65°C~ 150°C Lead temperature (soldering 10 sec.) ………………………………………………… 260°C Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 9/21/2005 Rev.3.01 www.SiliconStandard.com 3 of 19 SS6782G TEST CIRCUIT Voltage Source - + ABV BBV R1 560 DIS DSW ICOB LEB2 R3 560 R4 560 GREEN ORANGE Voltage Source - + YELLOW - + BTS VCC ADJ SEL3 LEB1 GND R5 560 RED Voltage Source VCC (5V) VCC V1 (0.95V) V2 (3V) 100K R2 SS6782G SEL1 SEL2 MODE ICOA LEA2 VCC VCC VCC TMR ATS LEA1 - + R8 560 R7 560 ORANGE Voltage Source RED VCC R6 560 GREEN ELECTRICAL CHARACTERISTICS (TA=25°C, VCC=5V, unless otherwise specified) (Note1) PARAMETER Supply Voltage Supply Current Battery Low Before Initial Timer After Initial Timer (SEL3>3V) Voltage Protection Limit (SEL33V) (SEL33V) 0 Fig. 7 Temperature (°C) ABV and BBV (High) Limit vs. Temperature (SEL3 VCC - 0.3V Acceptable ABV/BBV Range: Before initial timer: 0.16V~2.7V After initial timer: 0.69V~2.7V Temperature Protection Mode: Enters charging-suspended mode when temperature is either too low or too high, same as abnormal battery voltage. Latch for chargesuspending function is provided for high temperature protection, but not for low temperature protection. (b) VCC - 1.4V> SEL3 > V cc - 0.4V 2 Acceptable ABV/BBV Range: Before initial timer: 0.16V~2.7V After initial timer: 0.69V~2.7V Temperature Protection Mode: If temperature is too high, battery charging is regarded as completed. If temperature is too low, function of ∆T / ∆t detection is disabled, just as if the thermistor did not exist. (c) V cc - 0.4V>SEL3 >1.4V 2 Acceptable ABV/BBV Range: Before initial timer: 0.16V~2 V After initial timer: 1.2V~2V Temperature Protection Mode: Enters the charging-suspended mode when temperature is too low or too high, same as abnormal battery voltage. Latch for charging-suspended function is provided for high temperature protection, but not for low temperature protection. 9/21/2005 Rev.3.01 www.SiliconStandard.com 11 of 19 SS6782G (d) 0.3V> SEL3 Acceptable ABV/BBV Range: Before initial timer: 0.16V~2 V After initial timer:1.2V~2V Temperature Protection Mode: If temperature is too high, battery charging is regarded as complete. If temperature is too low, t he ∆ t/ ∆ t detection function is disabled, just as if the thermistor did not exist. Battery Voltage Measurement The SS6782G measures the battery voltage through ABV and BBV pins, which are connected to the battery positive terminals through a resistordivider network, as shown in Fig. 14. The acceptable limit of divided battery voltage is determined by the input voltage of SEL3 pin. TABLE 1 BATTERY CELLS 2~4 3~6 4~8 5~10 6~12 8~16 RA/RB 2 3.3 4.9 6.4 7.8 10.8 RA kΩ 240 300 300 300 310 390 RB kΩ 120 91 62 47 39 36 For SEL3 < ((VCC/2) -0.4V), the suggested divider resistances of RA and RB for the corresponding number of battery cells are shown below: TABLE 2 BATTERY CELLS 2 3 4 5 RA/RB 1 2 3 4 5 7 9 11 15 RA (kΩ ) 240 240 240 300 300 360 360 390 410 RB (kΩ ) 240 120 80 75 60 51 40 36 27 VBAT RA R6 + C5 100K 4.7µF C6 0.1µF ABV/BBV SS6782G 6 8 10 12 16 RB Fig. 14 Battery Voltage Divider For SEL3 > ((VCC/2) + 0.4V), the suggested divider resistances of RA and RB for the corresponding number of battery cells are as below: Battery Temperature Measurement The SS6782G employs a negative temperature coefficient (NTC) thermistor to measure the bat’ tery s temperature. The thermistor is inherently nonlinear with respect to temperature. To reduce the effect of nonlinearity, a resistor-divider network in parallel with the thermistor is recommended. A typical application circuit is shown in Fig. 15. 9/21/2005 Rev.3.01 www.SiliconStandard.com 12 of 19 SS6782G VCC VBAT Rx 5 VCC ATS/BTS C7 0.1µF Thermistor Ry//RTH × Vcc Rx + (Ry// RTL) RTL= The resistance of thermistor at lower limit of temperature protection. 0.72 Vcc = SS6782G Ry 16 GND Fig. 15 Battery Temperature Sense Circuit with a Negative Temperature-Coefficient (NTC) Thermistor The calculation for Rx and Ry in the circuit is as follows: Ry / /RTH 0.29 Vcc = × Vcc Rx + (Ry / / RTH) RTH= The resistance of thermistor at upper limit of temperature protection. Substitution and rearranging the equations yields RTL × RTH Rx= 2.061 × RTL − RTH 5.3 × RTL × RTH Ry = RTL − 6.3RTH If the temperature characteristic of the thermistor is like that of the SEMITEC 103AT-2, the resistance of Rx and Ry is tabulated below for different values of TL and TH: (note: TL is the lower temperature limit and TH is the upper temperature limit.) TABLE 3 Values of Rx and Ry at TL = 0°C TH (°C) 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 Rx(kΩ) 10.1 9.7 9.4 9.0 8.7 8.4 8.1 7.8 7.5 7.2 7.0 6.8 6.5 6.3 6.1 5.9 5.7 5.5 5.3 5.2 5.0 Ry (kΩ) 551.1 300.7 204.8 153.9 122.8 101.8 86.5 75.0 66.0 58.7 52.8 47.8 43.6 39.9 36.8 34.0 31.6 29.5 27.5 25.8 24.3 TABLE 4 Values of Rx and Ry at TL = -10°C TH (°C) 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Rx (kΩ) 11.4 11.0 10.6 10.2 9.8 9.5 9.1 8.8 8.5 8.2 7.9 7.6 7.4 7.1 6.9 6.7 6.4 6.2 6.0 5.8 5.6 Ry (kΩ) 95.6 85.0 76.2 68.9 62.8 57.5 52.9 48.8 45.3 42.1 39.4 36.8 34.6 32.5 30.7 29.0 27.4 26.0 24.6 23.4 22.2 9/21/2005 Rev.3.01 www.SiliconStandard.com 13 of 19 SS6782G Setting the ADJ Pin Voltage The slope of ∆T / ∆t detection is determined by the ADJ pin voltage of the SS6782G. The calculation of ADJ pin voltage is shown in the following procedure followed by an example. Procedure TABLE 5 ADJ Pin Voltage (TL=0°C, TH=50°C) (a) First, determine the temperature protection limits TH and TL. Then, substitute TH & TL into the following equation: ∆V TS 0.72V CC − 0.29V CC 0.43V CC = = ∆TBASE TH − TL TH − TL ∆T / ∆t S.T. 40 min. (2C) 80 min. (1C) 120 min. (0.67C) (b) Determine the safety timer to obtain the value of ∆tBASE . 56(sec.) ∆tBASE(sec.) = × Safety Timer (min .) 80(min .) (c) Determine the expected slope of ∆T / ∆t at which temperature rises y°C in x seconds and fast charge is subsequently cut off. ∆T y = ∆t x (d) Calculate the value of VADJ ∆T ∆V TS V ADJ = 25 × × × ∆t BASE ∆TBASE ∆t 160 min. (0.5C) 200 min. (0.4C) 240 min. (0.33C) 0.75 1.0 1.25 (°C/min.) (°C/min.) (°C/min.) 0.37 0.5 0.63 0.75 1.12 1.5 1.87 2.25 1.0 1.5 2.0 2.5 3.0 1.25 1.87 2.5 3.12 3.75 ∆ T / ∆t = 1 = 0. 0166 60 (d) VADJ =25 x 0.043 x 0.0166 x 56 = 1(V) If the temperature range is from 0°C to 50°C, the voltage of VADJ under different setting conditions should be set as tabulated below. A similar table for temperature range from 0°C to 60°C is shown below. TABLE 6 ADJ Pin Voltage (TL=0°C, TH=60°C) ∆T / ∆t S.T. 40 min. (2C) 80 min. (1C) 120 min. (0.67C) 160 min. (0.5C) 200 min. (0.4C) 0.75 1.0 1.25 (°C/min.) (°C/min.) (°C/min.) 0.31 0.62 0.94 1.25 1.56 1.87 0.42 0.84 1.25 1.67 2.08 2.5 0.52 1.05 1.56 2.08 2.60 3.12 Example (a) Let TH=50°C, TL=0°C, VCC =5V. We have ∆VTS 0.43 × 5 = = 0.043V/ °C ∆TBASE 50 − 0 which means that VTS decreases 43mV as temperature rises 1°C. (b) If safety timer is equal to 80 minutes, ∆tBASE is then 56 seconds. (c) If fast charging should be terminated when temperature rises 1°C in 60 seconds, then 240 min. (0.33C) Setting the Period of Safety Timer The SS6782G provides a method for linearly adjusting the period of safety timer with an external resistor connected from TMR pin to GND. The relation between safety timer length and the external resistor (RTMR) is shown in Fig. 16. The table following shows the resistor values. 9/21/2005 Rev.3.01 www.SiliconStandard.com 14 of 19 SS6782G for some of the commonly chosen safety timer periods. Also shown in the table is their corresponding oscillator frequencies. TABLE 8 The Operating Mode of SS6782G 800 For relevant information, please contact SSC directly. MODE pin VCC Mode Test Function Safety timer period scaled down to 1/32.... etc. -∆ V detection disabled 600 RTMR (kΩ) 400 Floating GND Normal Normal operation AC 200 0 0 100 200 300 400 500 The LED Display and Trickle Charge Modes The SS6782G provides two LED display modes and five pulsed trickle charge modes. The modes of LED display and trickle charge are determined by the tri-level inputs, SEL1 and Osc.Freq. (kHz) 262.4 131.2 65.6 43.7 32.8 21.9 16.4 10.9 7.3 5.5 Safety timer (min.) 10 20 40 60 80 120 160 240 360 480 SEL2 pins, as in the TABLE 9. TABLE 9 Mode of LED Display and Trickle Charge SEL1 SEL2 VCC Floating GND VCC Floating GND VCC Floating GND Trickle Charge Duty N/A 1/32 1/64 1/128 1/256 N/A 1/32 1/64 1/128 LED Display Mode Type 1 Type 1 Type 1 Type 1 Type 1 Type 2 Type 2 Type 2 Type 2 Safety Timer (min.) Fig. 16 Safety Timer vs RTMR TABLE 7 RTMR (kΩ) 11 23 48 74 100 152 206 314 491 667 VCC Floating Selecting Mode of Operation The SS6782G provides three modes of operation: normal, test, and AC mode, determined by the setting of the MODE pin according to TABLE 8. The SS6782G will operate normally when the MODE pin is left floating (a 0.1µF capacitor is recommended to be tied to the MODE pin if the charging circuit works in a noisy environment). When the MODE pin is biased to GND, the function of −∆V detection is disabled. When the MODE pin is biased to VCC, the SS6782G enters the test mode. The test mode can be used to significantly reduce production test time. GND Displaying the Battery Charging Status The SS6782G provides four open-drain outputs, in which LEA1 and LEA2 are used to indicate the battery charging status of pack A, and LEB1 and LEB2 are used to indicate battery charging status of pack B. Refering to the table of LED display modes (TABLE 6), depending on the setting of SEL1 and SEL2 pins, the outputs of LEA1, LEA2, LEB1, and LEB2 pins are shown in the following table: 9/21/2005 Rev.3.01 www.SiliconStandard.com 15 of 19 SS6782G TYPE 1 Power On LEA1/ LEB1 LEA2/ LEB2 TYPE 2 Power On LEA1/ LEB1 LEA2/ LEB2 1HZ 1HZ Wait 1HZ 1HZ Charge ON 4HZ Full OFF ON Abnormal 4HZ OFF 1HZ OFF Wait ON ON Charge ON OFF Full OFF ON Abnormal OFF OFF Test Mode Fig. 17 shows the timing diagram for externally controlled ADJ, ABV, BBV, ATS, BTS, SEL1 and SEL2 pin voltages in a recommended SS6782G test scheme, utilizing TEST mode function. Output waveforms of LEA1, LEA2, LEB1, LEB2, ICOA and ICOB f rom a p roperly functioning SS6782G are also shown in the figure. For detailed information please consult with SSC staff directly. Charging Current Control As shown in the typical application circuit, the S S6 782 G o ffers two open-drain output pins, ICOA and ICOB pins, to control the charging current of battery pack A and pack B. When fast charging is completed, the SS6782G enters the trickle charge mode. In trickle charge mode, the ICOA or ICOB output pins switch with predetermined duty cycle. Refering to the table of trickle charge mode (TABLE 6), the duty cycle is determined by the setting of SEL1 and SEL2 pins. The following table summarizes how ICOA and ICOB pins correspond to various charging states. Power Wait Fast Charge Fault ON ON Charging Completed Conditions ICOA/ ICOB ON ON OFF See pin 14 & 15 ON 9/21/2005 Rev.3.01 www.SiliconStandard.com 16 of 19 SS6782G TIMING DIAGRAM VCC, SEL3, MODE=5V, (DSW FREQ.=820KHz, 25 TIMES of 32.8K) Power Init. PEAK TIMER TEST ON ADJ -∆V TEST -∆V DISABLE TEST ∆T/∆t TEST SAFETY TIMER TEST 5V 1.12V 3V (-0.15%) 2V 1.95V (A):ABV (B):BBV