SS6781BGNTR

SS6781B Battery Charge Controller FEATURES Fast Charge Control of NiMH/NiCd Batteries, even with a Fluctuating Charging Current. Fast Charge Termination by: ∆T / ∆t , − ∆V , 0 ∆V , Safety Timer, Maximum Temperature, Maximum Voltage. Linearly Adjustable ∆T / ∆t Detection Slope and Safety Timer. Adjustable Peak Voltage Timer for 0 ∆V . Battery Voltage Protection Range Selectable. 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 for Eliminating Memory Effect. Quick and Easy Testing for Production. 16-pin DIP or SO Packages. DESCRIPTION The SS6781B fast charge controller IC is designed for intelligent charging of NiMH or NiCd batteries without the risk of overcharge. − ∆V Detection (-0.25%), 0 ∆V detection (peak voltage timer) and ∆T / ∆t detection are the primary methods employed by the SS6781B to terminate fast charge. The fast charge can also be cut off by maximum battery voltage and maximum battery temperature detection along with the 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 SS6781B utilizes the combination of these two methods to achieve reliable decision of ending fast charge and prevent misacting caused by using − ∆V detection alone under certain conditions. Fig. 1 shows an example of charging curve of a battery charged by a fluctuating current from a NiMH battery charger, which uses the SS6781B controller IC to achieve optimal charging. This technique, in cooperating with the 0 ∆V detection (peak voltage timer), is particularly suitable for NiMH batteries, whose voltage drop is hardly significant yet temperature rises rapidly. 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 lack of temperature sensing thermistor. The safety timer period, mode of battery temperature protection, battery voltage protection range, pulsed trickle charge duty, and LED display mode are all adjustable or selectable. Discharge-before-charge function is included to get rid of memory effect of NiCd batteries without APPLICATIONS 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 = 600 mA Cell Capacity = 550 mA NiMH Battery 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 Resulting from an S S6 781B-Controlled Charger with a Fluctuating Charging Current Pb-free; RoHS-compliant 01/31/2008 Rev.1.00 www.SiliconStandard.com 1 Temperature (°C) Cell Voltage (V) 1.45 80 SS6781B the risk of overdischarging. Test mode is provided for charger manufactures to dramatically reduce production test time. TYPICAL APPLICATION CIRCUIT D1 R1 1K L1 220µH R5 120/0.5W U1 DC DE CF GND SS6563 BOOST IS VCC FB 8 7 6 5 + C4 220µF 1N5819 D2 IN5819 R2 20/5W R3 270 LED1 R8 300K + R9 91K BAT1 **BATTERY R7 RX THERMISTOR SW 1 PB SW YELLOW LED2 R12 100K DSW ICON LED2 LED1 GND SEL1 SEL2 MODE 16 15 14 13 12 11 10 9 R16 680 GREEN RED R17 680 LED3 IN4148 C2 1µF C5 R10 100K C10 47nF 1 2 U2 PEAK VBT DIS VTS VCC ADJ SEL3 TMR 0.1µF R4 390K 1 2 3 D3 IN4148 RS 0.3/1W + C3 D4 C9 4.7µF C7 0.1µF Q1 MPS2222A R15 680 3 4 5 6 C1 470P 4 R14 + C11 C8 200K R6 50K R11 7 8 220µF RY C6 0.1µF 100µF R13 470K 0.1µF SS6781B 5.1K VIN 11~15V + U3 VIN C12 1µF 78L05 VOUT GND Q2 MMBT2222A + C13 10µF **3~5 NiMH/NiCd cells. Note: Charge Current=0.3/RS Ampere Safety Timer: 80min Battery Charge Circuit for Fluctuating Charging Current Application ORDERING INFORMATION SS6781BX X X X PIN CONFIGURATION P ACKING TYPE TR: TAPE & REEL TB: TUBE PACKAGE TYPE N: PLASTIC DIP S: SMALL OUTLINE C: COMMERCIAL G: LEAD FREE COMMERCIAL T OP VIEW PEAK VBT DIS VT S VCC A DJ SEL 3 T MR 1 2 3 4 16 15 14 13 12 DS W IC O N LE D 2 LE D 1 G ND 5 6 7 8 1 1 SEL 1 10 9 S EL 2 M ODE E xample: SS6781BCSTR in SO-16 Package & Tape & Reel Packing Type (CN is not available in TR packing type) SS6781BGSTR in SO-16 Lead Free Package & Tape & Reel Packing Type 01/31/2008 Rev.1.00 www.SiliconStandard.com 2 SS6781B ABSOLUTE MAXIMUM RATINGS Supply Voltage DC Voltage Applied on any pin Sink current of ICON pin, LED1 and LED2 pin Operating Temperature Range Storage Temperature Range Junction Temperature Range Lead Temperature (Soldering 10 sec) 5.5V 5.5V 20mA -40°C~ 85°C -65°C~ 150°C 125°C 260°C Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. TEST CIRCUIT VCC VOLTAGE SOURCE + YELLOW R1 560 PEAK VBT DIS VTS DSW ICON LED2 LED1 R3 56 0 R4 560 R5 56 0 GND SEL1 SEL2 MODE VCC VCC VCC VCC RED GREEN ORANGE - + VOLTAGE SOURCE VCC (5V) VCC V1 (0.95V) V2 (3V) 5.1K R2 SS6781B VCC ADJ SEL3 TMR 01/31/2008 Rev.1.00 www.SiliconStandard.com 3 SS6781B ELECTRICAL CHARACTERISTICS (TA=25°C, VCC=5V, unless otherwise specified.) (Note1) PARAMETER Supply Voltage Supply Current Battery Low During Initial Timer After Initial Timer (SEL3>3V) (SEL33V) (SEL33V) Fig. 9 Temperature (°C) VBT (High) Limit vs. Temperature (SEL33V, After Initial Timer) Fig.15 Temperature (°C) VBT (Low) Limit vs. Temperature (SEL3 (VCC/2) + 0.4V, the suggested divider resistance of RA and RB for the corresponding number of battery cells are as below: TABLE 2 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 Battery Temperature Measurement The SS6781B employs a negative temperature coefficient (NTC) thermistor to measure the battery’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. 18. VCC VBAT Rx 4 Thermistor C7 0.1µF 5 VCC VTS 36 AIC1781B Ry 12 GND For SEL3 < (VCC/2) -0.4V, the suggested divider resistance of RA and RB for the corresponding number of battery cells are as below: TABLE 3 BATTERY CELLS 2 3 4 5 6 8 10 12 16 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 Fig. 18 Battery Temperature Sense Circuit with a Negative Temperature Coefficient (NTC) Thermistor 01/31/2008 Rev.1.00 www.SiliconStandard.com 13 SS6781B 66 The calculation for Rx and Ry in the circuit is as following. Ry//RTH 0.29 VCC = x VCC Rx + (Ry// RTH) RTH= The resistance of thermistor at upper limit of temperature protection. Ry//R TL 0.72 VCC = x VCC Rx + (Ry// R TL ) RTL= The resistance of thermistor at lower limit of temperature protection. Substitution and rearranging the equations yield Rx= 2.061 × Ry = RTL × RTH RTL − RTH 5 . 3 × RTL × RTH RTL − 6 . 3 RTH 5.7 5.5 5.3 5.2 5.0 31.6 29.5 27.5 25.8 24.3 67 68 69 70 TABLE 5 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 If temperature characteristic of the thermistor is like that of SEMITEC 103AT-2, the resistance of Rx and Ry is tabulated for different TL and TH as below. (Note: TL is lower temperature limit and TH is upper temperature limit.) TABLE 4 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 01/31/2008 Rev.1.00 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 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 Setting the ADJ Pin Voltage The slope of ∆T/∆t detection is determined by ADJ pin voltage of the SS6781B. The calculation of ADJ pin voltage is shown in the following procedure followed by an example. www.SiliconStandard.com 14 SS6781B Procedure (a) First, determine the temperature protection limits TH and TL. Then, substitute TH & TL into the following equation: ∆V TS 0. 72 V CC − 0. 29 V CC 0. 43 V CC = = ∆TBASE TH − TL TH − TL (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 120 min. (0.67C) 160 min. (0.5C) 200 min. (0.4C) 240 min. (0.33C) 1.35 1.80 2.25 2.70 1.80 2.40 3.01 3.61 2.25 3.01 3.76 A similar table for temperature range from 0°C to 60°C is as below. TABLE 7 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) 240 min. (0.33C) 0.75 1.0 1.25 (°C/min.) (°C/min.) (°C/min.) 0.37 0.75 1.12 1.50 1.88 2.25 0.50 1.00 1.50 2.00 2.50 3.01 0.62 1.25 1.88 2.50 3.13 3.76 VADJ = 30 × ∆VTS ∆T × × ∆tBASE ∆TBASE ∆t Example VBT Range and Temperature Protection The acceptable voltage range of VBT pin and mode of temperature protection function is determined by the voltage of SEL3 pin, shown as the following: (a) SEL3 > VCC - 0.3V Acceptable VBT Range: Before initial timer: 0.16V~2.7V After initial timer: 0.69V~2.7V Temperature Protection Mode: Entering charge-suspending mode when temperature is either too low or too high, same as abnormal battery voltage. Latch for charge-suspending function is provided for high temperature protection, but not for low temperature protection. (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 charge should be terminated when temperature rises 1°C in 60 seconds, then 1 ∆T/∆t = = 0.0166 60 (d) VADJ =30 x 0.043x 0.0166 x 56 = 1.2(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. TABLE 6 ADJ pin Voltage (TL=0°C, TH=50°C) ∆T / ∆t S.T. 40 min. (2C) 80 min. (1C) 01/31/2008 Rev.1.00 (b) VCC - 1.4V> SEL3 > V cc + 0.4V 2 0.75 1.0 1.25 (°C/min.) (°C/min.) (°C/min.) Acceptable VBT 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 15 0.45 0.90 0.60 1.20 0.75 1.50 www.SiliconStandard.com SS6781B low, function of ∆T/∆t detection is disabled, just as thermistor is not existing. 120 100 V cc (c) - 0.4V>SEL3 >1.4V 2 Acceptable VBT Range: Before initial timer: 0.16V~2V After initial timer: 1.2V~2V Temperature Protection Mode: Entering charge-suspending mode when temperature is either too low or too high, same as abnormal battery voltage. Latch for charge-suspending function is provided for high temperature protection, but not for low temperature protection. (d) 0.3V> SEL3 Acceptable VBT Range: Before initial timer: 0.16V~2V After initial timer: 1.2V~2V 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 thermistor is not existing. Setting the Period of Safety Timer The SS6781B 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. 19. The table following shows the resistor values for some of the commonly chosen safety timer periods. Also shown in the table are their corresponding oscillator frequencies. RTIM (Kohm) 80 60 40 20 0 0 200 400 600 800 1000 1200 1400 Safety Timer (min.) Fig. 19 TABLE 8 RTMR (KΩ) Safety Timer vs. RTMR OSC. Freq.(KHz) Safety timer (min.) 0.9 2.2 3.5 5.1 7.8 10.9 17.5 26.2 2100 1049.6 704 518.4 353.6 264 174.4 116.8 20 40 60 80 120 160 240 360 Selecting Mode of Operation The SS6781B provides three modes of operation: normal, test, and AC mode determined by the setting of MODE pin according to TABLE 9. The AIC1781B will operate normally when the MODE pin is left floating (a 0.1µF capacitor is recommended to be tied to MODE pin if the charge 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 SS6781B enters the test mode. The test mode can be used to significantly reduce production test time. For relevant information please contact AIC directly. 01/31/2008 Rev.1.00 www.SiliconStandard.com 16 SS6781B TABLE 9 MODE pin VCC Floating GND The Operating Mode of SS6781B Mode Test Function Safety timer period scaled down to 1/512....etc. –∆V detection disabled TYPE 2 Power ON LED1 LED2 1Hz 1Hz Fault Charge Fast Charging Completed Conditions ON 4Hz Flashing OFF ON 4Hz Flashing OFF Normal Normal operation AC The Mode of LED Display and Trickle Charge The SS6781B provides two LED display modes and five-pulsed trickle charge modes. The tri-level inputs, SEL1 and SEL2 pins, as in the TABLE 6 determine the modes of LED display and trickle charge. TABLE 10 Mode of LED Display and Trickle Charge SEL1 SEL2 VCC Floating GND VCC Floating GND VCC Floating GND Trickle Charge LED Display Duty Mode N/A 1/32 1/64 1/128 1/256 N/A 1/32 1/64 1/128 Type 1 Type 1 Type 1 Type 1 Type 1 Type 2 Type 2 Type 2 Type 2 Charging Current Control As shown in the typical application circuit, the SS6781B offers an open-drained output pin, ICON pin, to control the charging current flow in fast charge state and switch on to inhibit the charging current flow in fault conditions. When fast charge is completed, the SS6781B enters the trickle charge mode. In trickle charge mode, the ICON pin output switches with predetermined duty cycle. Refer 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 ICON pin corresponds to various charging states. Charge Power Fast Fault ON Charging Completed Conditions ICON ON OFF See pin 10 & 11 ON VCC Floating GND Display the Battery Charging Status The SS6781B provides two open-drained outputs, LED1 and LED2, to indicate the battery charging status. Refer to the table of LED display mode (TABLE 10), depending on the setting of SEL1 and SEL2 pins, the outputs of LED1 and LED2 pins are shown in the following table: TYPE 1 Fast Power Charge Fault ON Charging Completed Conditions LED1 LED2 1Hz OFF ON OFF OFF ON OFF OFF Test Mode Fig. 20 shows the timing diagram for externally controlled PEAK, ADJ, VBT, VTS, SEL1 and SEL2 pin voltages of a recommended SS6781B test scheme, utilizing TEST mode function. Output waveforms of LED1, LED2 and ICON of a properly functioning SS6781B are also shown in the figure. 01/31/2008 Rev.1.00 www.SiliconStandard.com 17 SS6781B TIMING DIAGRAM Power ON VCC, SEL3, MODE=5V, RTMR=2.9kΩ, (DSW FREQ.=820KHz, 25 TIMES of 32.8K) Init. PEAK TIMER TEST 5V -∆V TEST 0V -∆V DISABLE TEST ∆T/∆t TEST SAFETY TIMER TEST PEAK ADJ 3V 5V 1.12V