 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| SM6780AS NIPPON PRECISION CIRCUITS INC. Ni-Cd/Ni-MH Battery Charger IC OVERVIEW The SM6780AS is a quick charge control IC for Nickel-Cadmium (Ni-Cd) and Nickel Metal Hydride (Ni-MH) rechargeable batteries. It supports quick charge, supplemental and pulse trickle charging modes. The charging mode is selected automatically in response to the battery voltage, temperature and charging time. The quick charge uses either negative delta voltage detection (-V), temperature detection (T/t), or charging time cutoff to control the charging process. In addition, the quick charge mode can be placed on hold, if the battery voltage or battery temperature are abnormal, until normal conditions are restored. The SM6780AS requires few external components to realize a high-stability quick charge battery charger. FEATURES s s s PINOUT (Top view) s s s s s s s s Ni-Cd/Ni-MH battery quick charge control -V, T/t, and maximum charge time cutoffs 3 charge modes (quick charge, supplemental, pulse trickle charge) 3 selectable charge times (80, 120, and 240 minutes) Charge condition LED indicator output (on, pulsed, off) Low power dissipation mode 4.0 to 5.5V operating supply voltage 300sec (typ) -V detection invalid time 8mV (typ) -V detection accuracy 25mV/min (typ) T/t detection accuracy 8-pin SOP package TIME CHGN 6780AS LEDN BATT VSS INH VDD TEMP ORDERING INFORMATION Device SM6780AS Package 8-pin SOP PACKAGE DIMENSIONS (Unit: mm) 0.15 + 0.1 - 0.05 4.4 0.2 6.2 0.3 0.695typ 5.2 0.3 0.05 0.05 1.5 0.1 1.27 0.10 0.4 0.1 0.12 M 0.4 0.2 0 to 10 NIPPON PRECISION CIRCUITS--1 SM6780AS BLOCK DIAGRAM VDD DC Input VDD TIME Current Source CHGN Reference Regulators OSC Timer Mode Selector CHG Driver BATT VDD Maximum Cell-voltage Check -V Function Block Timing Control Logic LEDN Input Select Battery Pack A/D V/t Function Block NTC TEMP Temp Check Charge Control Logic LED Driver VDD INH VSS PIN DESCRIPTION Number 1 Name TIME Description Charge time select 3-level input. HIGH: 240 minutes, MID (VDD /2): 120 minutes, LOW: 80 minutes Charge indicator LED driver output. Open-drain output. LOW-level output in quick charge mode. 1Hz pulse output when abnormal battery voltage or temperature is detected during quick charge mode. High impedance output in supplemental and trickle charge modes. Battery voltage detector input. Connect a high-impedance resistor voltage divider between the poles of the battery for voltage detection. Ground Battery temperature thermistor sensor voltage input Supply Charge inhibit input. Charging is stopped when HIGH. Charging resumes with the same charge parameters in force prior to the stop when INH goes LOW again. Charger control output. Open-drain output. Battery charging current flows when CHGN is high impedance. Charge current stops when LOW. High-impedance output in quick charge mode, and pulse output in supplemental and trickle charge modes. 2 LEDN 3 4 5 6 7 BATT VSS TEMP VDD INH 8 CHGN NIPPON PRECISION CIRCUITS--2 SM6780AS SPECIFICATIONS Absolute Maximum Ratings VSS = 0V Parameter Supply voltage range Input voltage range Storage temperature range Operating temperature range Power dissipation Symbol V DD V IN Tstg Topr PD Condition Rating -0.3 to 7.0 -0.3 to 7.0 -55 to 125 0 to 85 150 Unit V V C C mW DC Characteristics 1 VDD = 4.0 to 5.5V, VSS = 0V, Ta = 25C Parameter Maximum temperature voltage High-temperature sense voltage Low-temperature sense voltage Maximum battery voltage Symbol V MXT V HTS VLTS V MXV Condition V TEMP V MXT charge cutoff V HTS V TEMP V LTS charge start V TEMP > V LTS charge prohibition V BATT > V MXV charge cutoff or prohibition Rating 0.225VDD 0.25VDD 0.4VDD 2.0 Variation 5% 5% 5% 5% Unit V V V V DC Characteristics 2 VDD = 4.0 to 5.5V, VSS = 0V, Ta = 0 to 85C unless otherwise noted Rating Parameter VDD supply voltage BATT input voltage TEMP input voltage INH HIGH-level input voltage INH LOW-level input voltage TIME HIGH-level input voltage TIME MID-level input voltage TIME LOW-level input voltage BATT -V detection voltage range LEDN output pulse frequency BATT standby voltage VDD current consumption VDD standby current LEDN, CHGN sink current INH, TIME input leakage current LEDN, CHGN output leakage current Symbol VDD VBATT V TEMP V IH1 V IL1 V IH2 V IM V IL2 V DET fLED VSTB IDD ISTB IOL IL IOZ V DD = 5V, no load V DD = 5V, V BATT = V DD, no load VOL = V SS + 0.8V V INH = V TIME = V SS to V DD Disabled when V TEMP < 0.5V Condition min 4.0 0 0.5 0.7 - V DD - 0.5 (VDD /2) - 0.5 - 1 - V DD - 1.5 - - 10 - -5 typ 5.0 - - - - - - - - 1 - - - - - - max 5.5 V DD V DD - 0.1 - (VDD /2) + 0.5 0.5 2 - V DD - 0.5 0.5 1 - 1 - V V V V V V V V V Hz V mA A mA A A Unit NIPPON PRECISION CIRCUITS--3 SM6780AS FUNCTIONAL DESCRIPTION Charger Operation The SM6780AS battery charger operation starts when the power is applied or when standby mode is released. The charging operation is determined by the BATT and TEMP pin states, and the timer mode selected. After charging starts, the battery voltage and temperature are monitored to check that they are within quick charging rated ranges. If within rated range, quick charge mode is selected. If outside rated range, pulse trickle charge mode is selected. Quick charge uses either negative delta voltage detection (-V), temperature detection (T/t), or charging time cutoff to terminate the charging process. The charging mode changes to supplemental charge mode when quick charge mode is completed. Supplemental mode terminates when the charging time finishes or battery is full, and the charging mode changes to pulse trickle mode. Charging Rate The charging rate is determined by the external charger current source. If the quick charge mode charging rate is considered as unity, then the supplemental charging rate is 1/16, and the pulse trickle charging rate is 1/256. The charging rate for supplemental and pulse trickle modes are shown in figure 1. The CHGN output is high impedance when the charging current is flowing, and LOW when the current stops. 286s Hi-Z Low Quick charge mode 286s 4576s Supplemental charge mode 73.1ms Pulse trickle mode Start (power ON or battery insertion) Figure 1. CHGN output (external charger control) Charging Status Indicator LED Control (LEDN) The SM6780AS LEDN output can be used to drive a charging status indicator LED. The LED timing when power is applied or standby mode is released is shown in figure 2. In quick charge mode, the LEDN output is LOW and the LED turns ON. If the battery temperature or battery voltage exceeds the charging rated ranges, the LEDN output pulses at a frequency of 1Hz to indicate battery out-of-range condition. In supplemental and pulse trickle modes, the LEDN output is high impedance and the LED turns OFF. Hi-Z LED OFF Low Approximately Approximately 3.5 s 1.5 s Power ON or Standby mode cancel LED ON Depends on charge mode Figure 2. LEDN output timing NIPPON PRECISION CIRCUITS--4 SM6780AS Battery Voltage and Temperature Detection The battery voltage detector input is BATT. The charger treats the input voltage as the equivalent voltage of a single cell. For multiple cells (connected in series), a high-resistance (> 100k) battery divider can be used to input the voltage equivalent of a single cell, as shown in figure 3. Battery Ra BATT pin Rb Ra =N-1 Rb N:Number of cells Figure 3. BATT connection example The battery temperature detector input is TEMP. The input voltage is provided by a negative temperature coefficient thermistor (NTC thermistor) located in close proximity to the battery, as shown in figure 4. The input voltage range is 0.5V to VDD. Rc TEMP pin Battery NTC Rd Figure 4. TEMP connection example Note that the thermistor temperature characteristics are non-linear, so a correction resistance Rc should be used for linearity correction. The temperature rating of resistances Rc and Rd should be chosen to match the battery temperature range rating. If the temperature detection function is not used, the TEMP input should be fixed at a potential in the range 0.25VDD to 0.4VDD. NIPPON PRECISION CIRCUITS--5 SM6780AS Charging Modes The SM6780AS has 3 modes of operation: quick charge, supplemental charge, and pulse trickle mode. The SM6780AS uses the various detection functions to monitor the state of the battery and select the charging mode automatically. In quick charge mode, charging occurs at a rate set by the external current source. In supplemental charge mode, the battery is charged by current pulses to the full stable capacity of the chemical substances within the battery. Pulse trickle mode maintains the level within the battery, compensating for internal losses. Cell voltage CHGN output Hi-Z Low Quick charge mode Supplemental charge mode Quick charge mode end Charge complete Pulse trickle mode Start Figure 5. Charging mode, battery voltage and charging current Quick (Supplemental) Charge Conditions -- Battery Check The SM6780AS monitors the battery voltage and battery temperature to confirm the values are within the rated range of the battery during quick charge and supplemental charging modes to realize a highstability battery charger. If the battery voltage or battery temperature charging rating is exceeded before quick charging mode terminates, the charging mode is placed on hold. The VBATT VTEMP internal timer continues to operate, and pulse trickle charging occurs. The LEDN output pulses at a rate of approximately 1Hz. If the charging rating is exceeded during supplemental charging mode, the mode terminates and charging switches to pulse trickle mode. Maximum cell Voltage 2.0V Low temperature sense Voltage (0.4 x VDD) Charge valid range Charge valid range High temperature sense Voltage (0.25 x VDD) Maximum temperature Voltage (0.225 x VDD) 0V Pulse trickle mode Power ON Quick charge mode Quick charge is suspended Pulse trickle mode Quick charge mode Quick charge restart Quick charge start High-temperature quick charge hold state: V TEMP < V MXT (0.225 x V DD ) High-temperature quick charge hold release state: VTEMP > V HTS (0.25 x V DD ) Figure 6. Quick (supplemental) charge ranges NIPPON PRECISION CIRCUITS--6 SM6780AS -V Invalid Time Generally, the battery voltage becomes unstable just after quick charging starts, so the -V battery voltage detection is disabled for 5 minutes to avoid error in battery voltage detection. However, the T/t temperature detection function continues to operate. After the -V detection is enabled, both detection functions operate. -V Detection (BATT) After Ni-Cd and Ni-MH batteries are fully charged in quick charge mode, the battery voltage begins to drop after reaching a peak value. The SM6780AS monitors the delta voltage (-V) to help determine when the battery is fully charged. When the voltage has fallen a minimum of 8mV (typ), the battery is fully charged and quick charge mode terminates. Note that -V detection is disabled for 5 minutes when quick charge mode is first started to avoid error in battery voltage detection, as described in the previous section. 8mV Vpeak Cell voltage Quick charge time - V detect Figure 7. Battery voltage change T/t Detection (TEMP) When Ni-Cd and Ni-MH batteries are close to full charge in quick charge mode, the temperature of the battery begins to greatly increase. The SM6780AS monitors the temperature change rate (V/t) to help determine when the battery is fully charged. When the temperature voltage on TEMP decreases by a minimum of 25mV (typ) within a 60-second interval, the battery is considered to be fully charged and quick charge mode terminates. Note that the TEMP voltage decreases with increasing temperature due to the negative temperature coefficient of the thermistor. Cell voltage Cell voltage t 25mV Voltage Voltage T Cell temperature 60s VTEMP Quick charge time Quick charge time T/t detect Figure 8. Battery temperature change Figure 9. VTEMP change NIPPON PRECISION CIRCUITS--7 SM6780AS Maximum Charging Time (TIME) The SM6780AS supports 3 different maximum charging time settings, in quick charge and supplemental charge modes, which can be selected on the 3-level input TIME (HIGH, MID, LOW). HIGH level is achieved by pull-up, LOW level by pullVDD = 5V, Ta = 25C Quick charge/supplemental charge time (minutes) TIME voltage level min HIGH MID LOW 192 96 64 typ 240 120 80 max 288 144 96 down, and MID level by a high-resistance voltage divider arrangement to set the voltage at VDD/2. The voltage level on TIME should only be switched in standby mode. Quick (Supplemental) Charge Inhibit (INH) When INH goes HIGH, quick charge mode or supplemental charge mode operation stops. While INH is HIGH, the internal timer stops and pulse trickle charging occurs. When INH goes LOW, the charging mode is restored to the previously active mode and the internal timer restarts. Standby Mode When the BATT input voltage is VSTB, the SM6780AS is in standby mode. In this mode, the internal timer is reset, and the LEDN and CHGN outputs become high impedance. Standby mode is released when the voltage applied to BATT falls below VSTB. NIPPON PRECISION CIRCUITS--8 SM6780AS Charging Flow Diagram Supply applied Standby mode released LED ON Battery check (maximum battery voltage: VBATT 2V) and (battery temperature: 0.225VDD VTEMP 0.4VDD) continuously battery check operation OK Maximum quick charge time count start Initial timer (5 minutes) count start - V detection disabled T/t detection enabled Not OK Battery check OK Maximum battery voltage: VBATT 2V and battery temperature: 0.25VDD VTEMP 0.4VDD Quick charge mode LEDN = LOW (ON) CHGN = High impedance - V detection or T/t detection or maximum charge time passed Battery check not OK Battery out-of-range Pulse trickle mode charging LEDN = pulse (flashing) CHGN = pulse Maximum charging time passed Maximum supplemental charge time count start Supplemental mode LEDN = High impedance (OFF) CHGN = pulse Battery check not OK or maximum charging time passed Charging terminates Pulse trickle mode charging LEDN = High impedance (OFF) CHGN = pulse NIPPON PRECISION CIRCUITS--9 SM6780AS Charging Operating Status Conditions Charging status INH Quick charge Quick charge hold Quick charge inhibit Supplemental charge Supplemental charge inhibit Pulse trickle Standby LOW LOW HIGH LOW HIGH - - Battery check OK Yes No - OK OK - - Charging mode CHGN output1 LEDN output Internal timer Quick charge Pulse trickle Pulse trickle Supplemental Pulse trickle Pulse trickle - High impedance 13.68Hz, 3.91% duty 13.68Hz, 3.91% duty 218Hz, 6.25% duty 13.68Hz, 3.91% duty 13.68Hz, 3.91% duty High impedance LOW (ON) 1Hz (pulsing) Same condition as when INH went HIGH High impedance (OFF) High impedance (OFF) High impedance (OFF) High impedance (OFF) Count Count Hold Count Hold - Reset 1. Frequency and duty are typical values. TYPICAL APPLICATION CIRCUIT External current source VBB 12V R1 5.1k Q1 2SC945 IN 78L05 OUT VSS 5V VBEQ2 Q2 2SD525 R2 4/5W ICHG ICHG = = 5 - VBEQ2 R2 5 - 0.65 4 VDD 5V R6 33k R5 1.8k R7 100k 8 7 5 3 Q3 2SC945 SW2 R12 12k SM6780AS 6 VDD LEDN TIME VSS CHGN INH TEMP BATT R3 100k SW1 R4 100k 2 1 4 R8 100k R9 200k R10 200k NTC R:10k (at 25 C) B:3435K R11 640 R13 14k R9 =N-1 R10 N= Number of cells Note that the above circuit is an example circuit to demonstrate the connections for device functions. Battery charger operation is not guaranteed. NIPPON PRECISION CIRCUITS--10 SM6780AS NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without further testing or modification. The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter, including compliance with export controls on the distribution or dissemination of the products. Customers shall not export, directly or indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies. NIPPON PRECISION CIRCUITS INC. 4-3, Fukuzumi 2-chome Koto-ku, Tokyo 135-8430, Japan Telephone: 03-3642-6661 Facsimile: 03-3642-6698 NC9918AE 2000.05 NIPPON PRECISION CIRCUITS INC. NIPPON PRECISION CIRCUITS--11 |
Price & Availability of SM6780AS
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |