Features * * * * * * * Constant Charge Current 3 h - 24 h Charge Time Programmable Low-cost DC Regulator Overtemperature Protection Charge-mode Indication Operation Starts at the Moment of Battery Insertion Fast Charge-time Test Mode Charge Timer IC Applications * Cordless Telephones * Low-cost Battery-charge Timers * Entertainment Equipment U2403B Description The U2403B is a monolithic integrated bipolar circuit which can be used in applications where time-controlled, constant current charge is required. The selection of the charge current versus timing is carried out by using the external circuit at pins 2, 3 and 4. For high current requirements, an external transistor is recommended in series with the battery. To protect the IC against high power loss (typically > 140C), the oscillator will be shut down when the reference voltage is switched off (0 V). The latter also takes place when there is a saturation caused by collector voltage at pin 1. When the overtemperature has disappeared and the collector voltage at pin 1 has exceeded the supply voltage (V1 > VS), charge time operation continues (see flow chart in Figure 4 on page 6). Rev. 4776A-INDCO-11/03 Figure 1. Block Diagram with External Circuit C1 R1 Power supply AC/DC LED2 Battery inserted LED1 R5 Charge Ready LED VS 8 Charge mode indicator max 140C GND 6 Power supply VS = 3.5 to 12 V 5 Test mode STM Timer and control logic VRef = 1.5 V/0.1 V/0 V VRef 1 V1 i + Shunt RC oscillator - 2 3 4 Sense R3 2 7 Osc R4 C4 U2403B 4776A-INDCO-11/03 U2403B Pin Configuration Figure 2. Pinning DIP8/SO8 V1 1 8 LED V2 2 7 GND U2403B SENSE 3 6 VS OSC 4 5 STM Pin Description Pin Symbol 1 V1 Collector terminal Function 2 V2 Shunt emitter terminal 3 V3 Amplifier sense input 4 OSC Oscillator input 5 STM Test-mode switch 6 VS 7 GND Reference point, GND 8 LED Charge-mode indicator Supply voltage Pin 1, Collector Voltage V1 Pin 1 is an open-collector output. When V1 3 V, the charge cycle will be switched off until it has reached a value higher than the supply voltage, as shown in Figure 6 on page 10. Pin 2, Shunt Emitter The constant current source is supplied by the internal operational amplifier. The voltage across R3 is determined via the internal reference source. Ich = V3/R3 Pin 3, Amplifier Sense Input (Inverted) (V3 = Vsense) The voltage-regulated current source has a closed loop at pin 2, pin 3, and resistor R3. Pin 4, Oscillator Input R4, The selection of the current charge versus timing is carried out by using the external circuit at pins 2, 3, and 4. Typical values are given in Table 1 on page 5. C4 3 4776A-INDCO-11/03 Pin 5, Test-mode Switch for Charging Time The charging time, tch, is given by the following equation: 1 n t ch = --------- 2 f osc where: fosc = oscillator frequency (see Figure 3) n = frequency divider = 26, if STM open = 17, if STM = GND = 8, if STM = VS The first eight divider stages can be tested directly. 256 input tact signals at pin 4 create one tact signal at pin 5. Figure 3. Quick Test Timer 1/3 1 2 3 Pin 4 Pin 5 Example 256 Oscillator Pulse Test-mode The charge time is assumed to be 6 h. The values of R4 and C4 can be selected from Table 1 on page 5. For example: R4 = 470 kW C4 = 680 pF There is a frequency of approximately 3100 Hz at pin 4. It is possible to test the charge time of 6 h by running through the charge cycle for a very short time. By connecting pin 5 with GND, the test time is 42 s. By connecting pin 5 with pin 1 (V1), the test time is reduced to about 82.4 ms. R5 is connected in parallel to the LED2 and provides a protective bypass function for the LED (see Figure 1 on page 2). Pin 6, Supply Voltage, VS VS 3.1 V Power-on reset release (turn-on) VS 2.9 V Under-voltage reset VS 13 V Supply voltage limitation Pin 7, Ground 4 U2403B 4776A-INDCO-11/03 U2403B Pin 8, Charge Mode Indicator An open-collector output supplies constant current to LED1 after the active charge phase has been terminated. J max controls the function temperature for the final stage range. This is when the temperature is above 140C and the charge function is therefore switched off. Trickle Charge The trickle charge starts after the charge has been terminated. In this case, the internal reference voltage is reduced from 1.5 V to approximately 0.1 V. This means the charge current is decreased by the factor: K = 1.5 V/0.1 V = 15 Trickle current = Ich/15 + I6 (supply current) + I8 It is possible to reduce the trickle charge with resistor R6, as shown in Figure 7 on page 11 and Figure 8 on page 13. Charge Characteristics Table 1. Charge Time Test Time/Test-mode Switch STM Open VS Oscillator Components Frequency GND R4 (k) C4 (pF) fosc (Hz) 270 330 470 6213 3h 41.2 ms 21 s 510 430 300 4h 54.9 ms 28 s 620 430 300 330 470 680 4660 5h 68.6 ms 35 s 510 390 300 470 680 1000 3728 6h 82.4 ms 42 s 620 470 360 470 680 1000 3105 7h 96.1 ms 49 s 560 430 220 680 1000 2200 2663 8h 109.8 ms 56 s 620 470 200 680 1000 2200 2330 9h 123.6 ms 1 min 3 s 750 510 240 680 1000 2200 2071 10 h 137.3 ms 1 min 10 s 620 270 130 820 2200 4700 1864 12 h 164.8 ms 1 min 24 s 390 150 2200 4700 1553 16 h 219.7 ms 1 min 56 s 470 200 2200 4700 1165 5 4776A-INDCO-11/03 Figure 4. Flow Chart Start no Battery inserted Turn on VS > 3.5 V V3 = 1.5 V LED2 "ON" Timer start Test mode Open GND VS Divider 217 226 28 Tj > T yes no V1 < 3.0 V yes V3 0 V no Interrupt charging LED2 "OFF" Interrupt no Tj < Tmax yes no V1 > VS yes V3 = 0 V Continuous charging LED2 "ON" Continuous timing no End of timing yes LED2 "OFF" LED1 "ON" Trickle charge mode V3 = 100 mV Battery removed no yes Undervoltage reset 6 U2403B 4776A-INDCO-11/03 U2403B Absolute Maximum Ratings Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Reference point pin 7 (GND), unless otherwise specified. Parameters Pin Symbol Value Unit Supply current t 100 s 6 IS is 20 100 mA mA Currents 1 2 3 4 5 8 I1 -I2 I3 I4 I5 I8 300 310 1 15 -75 to +120 8 mA mA A mA A mA Voltages 1, 3, 5, 6, 8 2 4 V V2 V4 13.5 1.6 1.5 V V V Junction temperature Tj 150 C Ambient temperature Tamb -10 to +85 C Tstg -50 to +150 C Symbol Value Unit RthJA RthJA RthJA RthJA 120 220 140 80 K/W K/W K/W K/W Storage temperature range Thermal Resistance Parameters Junction ambient DIP8 SO8 on PC-board SO8 on ceramic SO8 on ceramic with thermal compound 7 4776A-INDCO-11/03 Electrical Characteristics VS = 6 V, Tamb = 25C, reference point pin 7 (GND), unless otherwise specified. Parameters Test Conditions Supply voltage limitation IS = 4 mA IS = 20 mA Supply current VS = 6 V Voltage Monitoring Pin Symbol Min. 6 6 VS VS Max. Unit 12.5 12.6 13.5 13.7 V V IS 1.4 2.2 V VTON 2.8 3.5 V VTOFF 2.5 3.2 V I8 3.0 6.0 mA 6 Turn-on threshold Turn-off threshold Charge-mode Indicator (LED) 8 LED current LED saturation voltage Typ. I8 = 3.7 mA V8 Leakage current Collector Terminal, Figure 6 on page 10 VS = 6 V Shunt emitter current R3 = 5.6 W Operational Sense Amplifier, Figure 1 on page 2 Input current V3 = 0 V Input voltage VRef = 1.5 V VRef = 100 mV VRef = 0 V Oscillator mV Ilkg 1.1 A ICO 15 55 A VTON VTOFF 2.55 VS - 1 V 3.35 VS - 0.4 V V V I2 250 285 mA I3 -0.6 0.08 A V3 V3 V3 1.42 40 -0.4 1.58 100 40 V mV mV Ilkg -0.5 0.1 A 1 Open-collector current Saturation threshold 960 -0.35 2 3.0 VS 3 1.5 70 4 Leakage current V4 = 0 to 0.85 V Threshold voltage Upper VT(u) 875 985 mV Oscillator frequency R4 = 160 kW, C4 = 2.2 nF R4 = 680 kW, C4 = 4.7 nF fosc fosc 2700 305 3050 345 Hz Hz I5 I5 40 -75 120 - 20 A A V0(H) V0(L) 1.7 0.5 2.5 1.0 V V Test Mode Switch (STM) 5 Input current V5 = 6 V V5 = 0 V Output voltage High Low 8 U2403B 4776A-INDCO-11/03 U2403B Internal Temperature Switch The internal temperature monitoring is active if the chip temperature rises above 140C. Above this temperature, the voltage at pin 3 returns to zero. Similarly, the charge current, Ich, reduces according to the equation: Ich = V3/R3 where Ich = 1 to 2 mA (IC supply current) The oscillator is connected to GND via pin 3 (V3) which holds the present time status. When the chip temperature decreases below the transition value, all functions are released and the charge time is continued. The process is reversible. If there is a higher power dissipation in the circuit (Tj > 140C), the temperature monitoring remains permanently activated (ON). The total cycle time is prolonged according to the interrupt-time duration, see Figure 5. Automatic Control Protection To reduce design costs, it is possible to select a transformer that requires minimum power supply. The output stage of the control is selected so that it is switched off before saturation is achieved (VCEsat = 3.0 V). In this case, the voltage at pin 3 is kept at a value of zero. The charge current is also zero, and the transformer is now an open-circuit impedance. The system becomes active again if V1 VS. The advantage of the system is that if sags of short duration appear on the mains voltage, or if the transformers used are too small, the charge duration will be increased, but the charge capacity remains the same, see Figure 6 on page 10. Figure 5. Charge Duration - Overtemperature Tj 140C Tj 130C Charge current I1 Timing Charge mode Counting timer t 9 4776A-INDCO-11/03 Figure 6. Charge Duration - V1 VS -V1 3.0 V 0V Charge current I1 Timing Charge mode t Counting timer Standard Applications Basic Example NiCd battery 750 mAh R1 = 510 W, 1/8 W Charging time: 3 h C1 = 47 F/ 16 V Charge current: 240 mA, 1/3 C R3 = 6.2 W, 1/2 W R4 = 300 kW Trickle charge: 19 mA < 1/40 C C4 = 470 pF R5 = 8.2 W, 1/2 W Table 2. Minimum Supply Voltage Special Requirements of Different Charge Times 10 Number of Cells DC Supply Minimum 1 6.8 V 2 8.3 V 3 9.8 V 4 11.3 V 5 12.8 V Table 3. R4, C4 Values for Different Charging Times Components 2h 4h 6h 7h 12 h R4 300 kW 430 kW 470 kW 470 kW 390 kW C4 330 pF 470 pF 680 pF 1 nF 2.2 nF U2403B 4776A-INDCO-11/03 U2403B Special Requirements for Table 4. R3, R5 Values for Different Charge Currents Different Charge Currents Components 240 mA 150 mA Basic Equations 100 mA 50 mA R3 6.2 W 10 W 15 W 30 W R5 8.2 W 15 W 22 W 68 W R1 = 0.5 V/IS IS = 1.8 mA R5 = V5/(Ich - 20 mA) Nominal Charge Current Ich = V3/R3 where V3 = 1.48 V (typically) Trickle Current: Ich = V3/R3 + I8 + IS Typical values are: V3 = 100 mV, I8 = 4.5 mA Figure 7. Standard Application DC supply R1 READY Ich C1 IS LED1 8 6 7 5 Charge R5 U2403B LED2 1 2 3 4 R4 R3 C4 11 4776A-INDCO-11/03 Booster and Trickle Charge Reduction Basic Example NiCd battery 1000 mAh R1 = 510 W, 1/8 W Charging time: 2 h C1 = 1000 F/ 16 V Charge current: 500 mA R 3 = 3 W, 1 W Trickle charge: 22 mA < 1/22 C R4 = 300 kW C4 = 330 pF R5 = 3.9 W, 1 W C2 = 1 F Table 5. Supply Voltage Special Requirements of Different Charge Times Number of Cells DC Supply Minimum 1 6.5 V 2 8.0 V 3 9.5 V 4 11.0 V 5 12.5 V Table 6. R4, C4 Values for Different Charge Times Components 2h 4h 6h 7h 12 h R4 300 kW 430 kW 470 kW 470 kW 390 kW C4 330 pF 470 pF 680 pF 1 nF 2.2 nF Special Requirements for Table 7. R3, R5 Values for Different Charge Currents Different Charge Currents Components 616 mA 493 mA 411 mA 296 mA R3 2.4 W 3W 3.6 W 5W R5 3.9 W 3.9 W 4.7 W 6.8 W R6 = 560 W, reduced trickle charge Basic Equations R1 = 0.5 V/IS R5 = V(LED2)/(Ich - 20 mA) Nominal Charge Current Ich = V3/R3 V3 = 1.48 V, typically 12 U2403B 4776A-INDCO-11/03 U2403B Trickle Current: Ich = V3/R3 + ILED1 + IS - I6 Typical values: V3 = 100 mV ILED1 = 4.5 mA IS = 1.8 mA Trickle-charge Reduction (I6) I6 = (VBatt + VD1)/R6 VD1 = 0.75 V Figure 8. Application for Charge Current > 250 mA BYW52 DC supply D1 R1 I6 R6 READY 8 Ich C2 LED1 C1 IS S1 6 7 5 U2403B R2 10 k BD 136 or BC 636 1 3 2 4 R4 Charge R5 LED2 R3 C4 S1: use for test only To meet the requirements of higher charge currents, an external booster transistor can be used (see Figure 8). As the temperature cannot be monitored in this case, a heat sink with a resonable size should be used for safe operation. The test mode switch S1 can be used for accelerated production check. Charge System at Higher Charge systems with higher voltages than VSmax can be realized with the additional expander circuitry, as shown in Figure 9 on page 14. This circuit contains a simple temVoltage up to 30 V perature monitoring function. When the temperature level is reached, the transistor, T3, is switched on. If T3 is switched on and there is current flow into pin 5, normal charge is terminated. 13 4776A-INDCO-11/03 Figure 9. U2403B for Higher Supply Voltage up to 30 V with Integrated Temperature Monitoring + + Battery R11 DC-Supply 30 V R10 NTC T3 - - D1 LED2 R1 R2 Ich D2 mounted on heatsink T2 8 6 7 5 T1 U2403B LED1 red R8 green C2 R5 R7 R6 1 2 3 LED1 normal charge LED2 trickle charge 4 R4 R1 = 1 k, R2= 10 k, R3 = f(IC), R4 = f(time), R5 = 13/0.5W, R6 = 1k R7 = 10 k, R8 = 47 k, R10 = 10 k, R11 = f(temp.), D1 = 1N4148 D2 = BZX85C10, C1 = 110 F/6 V, C2 = 10 nF, C4 = 330 pF R3 C4 R11 f(temp.) depends on number of cells Table 8. Value of R11 for Different Number of Cells Number of Cells R11 2 3 4 5 13 kW 8.2 kW 6.2 kW 4.7 kW Table 9. NTC Resistance at Different Temperatures 14 NTC Value NTC Resistance 25C 40C 50C 6.8 kW 3.9 kW 2.8 kW U2403B 4776A-INDCO-11/03 U2403B Ordering Information Extended Type Number Package Remarks U2403B-x DIP8 Tube U2403B-xFP SO8 Tube U2403B-xFPG3 SO8 Taped and reeled Package Information Package DIP8 Dimensions in mm 7.77 7.47 9.8 9.5 1.64 1.44 4.8 max 6.4 max 0.5 min 3.3 0.58 0.48 2.54 0.36 max 9.8 8.2 7.62 8 5 technical drawings according to DIN specifications 1 4 15 4776A-INDCO-11/03 Package SO8 Dimensions in mm 5.2 4.8 5.00 4.85 3.7 1.4 0.25 0.10 0.4 1.27 6.15 5.85 3.81 8 0.2 3.8 5 technical drawings according to DIN specifications 1 16 4 U2403B 4776A-INDCO-11/03 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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