Description Features SE1052 is a highly integrated solution for SMPS ¾ Constant Voltage and Constant Current Control applications requiring CV (constant voltage) and CC ¾ Low Voltage Operation (constant current) modes. It also has built-in LED ¾ Precision Internal Voltage References drivers specifically designed for stand-alone Battery ¾ Low External Component Count Charging applications. SE1052 integrates three ¾ Current Sink Output Stage voltage references, three operational amplifiers, and ¾ Easy Compensation two current sensing circuits together in the same IC. ¾ Low AC Mains Voltage Rejection one ¾ Rugged 1.5KV ESD withstand capability. operational amplifier, controls the output voltage. ¾ Internal 2 LED drivers The 2nd voltage reference, together with another ¾ Available in SOP8 and DIP-8 Package. operational amplifier, senses and limits the amount of ¾ RoHS Compliant and 100% Lead (Pb)-Free 1st The voltage reference, together with the current on the low side, hence the overall current at the output. The 3rd voltage reference and Application operational amplifier senses when the charging ¾ Adapters current drops to 10% of the programmed value. ¾ Digital Camera Chargers. During charging, SE1052 will turn on Red LED. When ¾ Cellphone Chargers. the charging is completed, SE1052 will turn on Green ¾ Other Battery Chargers LED. The SE1052 is available in SOP8 and DIP8 package. Ordering Information Device SOP8 and Pin Configuration DIP8 Top View SOP8 Top View Green 1 8 Red Output 2 GND 3 Vctrl 4 Package SE1052 Green 1 8 Red 7 Ictrl 6 Vsense Output 2 7 Ictrl 5 Vcc GND 3 6 Vsense Vctrl 4 5 Vcc DIP8 VOUT Fixed output voltages (Lead-free) Pin Description Name Pin# Type Function Green 1 Driver Turning on Green LED when the charging is completed. VOUT 2 Current Sink Output Output Pin. Sinking Current Only GND 3 Power Supply Ground Line. 0V Reference For All Voltages VCTRL 4 Analog Input Input Pin of the Voltage Control Loop VCC 5 Power Supply Positive Power Supply Line VSENSE 6 Analog Input Input Pin of the Current Control Loop ICTRL 7 Analog Input Input Pin of the Current Control Loop Red 8 Driver Turning on Red LED when the charging is in progress. Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 1 1.21V Absolute Maximum Rating Symbol Parameter Maximum Units VCC DC Supply Voltage 18 V VIN θJA Input Supply Voltage Thermal Resistance Junction to Ambient -0.3~ VCC 250 V °C/W TJ Operating Junction Temperature Range 0 to 125 °C -40 to 150 °C 260 °C TSTG Storage Temperature Range TLEAD Lead Temperature (Soldering 10 Sec) Electrical Characteristic VCC = 5.0V, TA = 25°C, unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit 0.7 1.2 2.5 mA Total Current Comsuption ICC Total Supply Current - not taking the output sinking ISINK=0 current into account Voltage Control Loop Gmv Transconduction Gain (Vctrl). Sink Current Only1） VREF LRV Voltage Control Loop Reference ISINK=0 Linear Regulation of Voltage Control Loop 2.4 1.198 Vcc= 2.5V to 18V Reference IIBV Input Bias Current (Vctrl) VOL Low Output Voltage at 10mA Sinking Current IOS ISINK=0 to 10mA 2） mA/mV 1.21 1.222 V 0.6 8 mV 70 Vctrl=Vcc, Ictrl=Vsense=GND, ISINK=10mA, G and R Pins Open Output Short Circuit Current. Output to VCC. Sink Vctrl=Vout=Vcc, Ictrl=Vsense=GND, Current Only G and R Pins Open 15 nA 250 350 mV 24 35 mA Current Control loop Gmi Transconduction Gain (Ictrl). Sink Current Only3） VSENSE LRI Current Control Loop Reference 4） Linear Regulation of Current Control Loop Reference IIBI Current out of pin Ictrl at -200mV VOL Low Output Voltage at 10mA Sinking Current IOS ISINK=0 to 5mA ISINK=0 7.2 192 Vcc=2.5V to 18V mA/mV 200 208 mV 0.8 4 mV 20 Vsense=Vcc, Ictrl=Vctrl=GND, ISINK=10mA, G and R Pins Open Output Short Circuit Current. Output to VCC. Sink Vsense=Vout=Vcc, Ictrl=Vctrl=GND, Current Only G and R Pins Open Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 2 15 uA 250 350 mV 24 35 mA Electrical Characteristic VCC = 5.0V, TA = 25°C, unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit Current Monitor Loop VTH Threshold Voltage of Turning Red Pin from Low to High 20 mV Hys Hysterisis of the comparator in Current Monitor Loop 14 mV 1. If the voltage on VCTRL (the negative input of the amplifier) is higher than the positive amplifier input (VREF=1.210V), and it is increased by 1mV, the sinking current at the output OUT will be increased by 2.4mA. 2. The internal Voltage Reference is set at 1.210V. The internal Voltage Reference is fixed by bandgap, and trimmed to 1% accuracy at room temperature. 3. When the positive input at ICTRL is lower than -200mV, and the voltage is decreased by 1mV, the sinking current at the output OUT will be increased by 2.9mA. 4. The internal current sense threshold is set to -200mV. The current control loop precision takes into account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the trans-conduction operational amplifier. Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 3 Typical Application Rs Vout+ To primary SE1052 1.210V Vcc Output Cs R2 Rout Rvc1 Cvc1 2.2nF C2 22 pF Vctrl 100mV Cic1 2.2nF Ric1 Rled 1K R1 10mV Red Ictrl Vsense GND Green LED_R LED_G Ric2 Rsense Note：0 ohms of Ric2 is recommended for LED charging indication function. Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 4 Vout- Application Hints Voltage Control The voltage loop is controlled via a first transconductance operational amplifier, the resistor bridge R1, R2, and the optocoupler which is directly connected to the output. The relation between the values of R1 and R2 should be chosen as written in Equation 1. R1 = R2 x Vref / (Vout - Vref) The current sinking outputs of the two trans-conductance operational amplifiers are connected together. This makes an ORing function which ensures that whenever the current or the voltage reaches too high values, the optocoupler is activated. The relation between the controlled current and the controlled output voltage can be described with a square characteristic as shown in the following V/I output-power graph. Eq1 Where Vout is the desired output voltage. To avoid the discharge of the load, the resistor bridge R1, R2 should be highly resistive. For this type of application, a total value of 100KΩ (or more) would be appropriate for the resistors R1 and R2. As an example, with R2 = 100KΩ, Vout = 4.10V, Vref = 1.210V, then R1 = 41.9KΩ. Note that if the low drop diode should be inserted between the load and the voltage regulation resistor bridge to avoid current flowing from the load through the resistor bridge, this drop should be taken into account in the above calculations by replacing Vout by (Vout + Vdrop). Current Control The current loop is controlled via the second trans-conductance operational amplifier, the sense resistor Rsense, and the optocoupler. The control equation is: Rsense x I-limit = Vsense Eq2 Rsense = Vsense / I-limit Eq3 where I-limit is the desired current limit, and Vsense is the threshold voltage for the current control loop. As an example, with I-limit = 1A, Vsense = -200mV, then Rsense = 200mΩ. Note that the Rsense resistor should be selected with the consideration of the Maximum Power in full load operations (P-limit). P-limit = Vsense x I-limit. Eq4 As an example, with I-limit = 1A, and Vsense =-200mV, P-limit = 200mW. Consequently, for most adapter and battery charger applications, a quarter-watt resistor to make the current sensing function is sufficient. Vsense threshold is achieved internally by a resistor bridge tied to the Vref voltage reference. Its middle point is tied to the positive input of the current control operational amplifier, and its foot is to be connected to lower potential point of the sense resistor as shown on the following figure. The resistors of this bridge are matched in layout to provide the best precision possible. Fig.2 Output voltage versus output current Compensation The voltage-control trans-conductance operational amplifier can be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in Fig.1. It consists of a capacitor Cvc1=2.2nF and a resistor Rcv1=470KΩ in series, connected in parallel with another capacitor Cvc2=22pF. The current-control trans-conductance operational amplifier can also be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in Fig.1. It consists of a capacitor Cic1=2.2nF and a resistor Ric1=22KΩ in series. When the Vcc voltage reaches 12V it could be interesting to limit the current coming through the output in the aim to reduce the dissipation of the device and increase the stability performances of the whole application. An example of a suitable Rout value could be 330Ω in series with the opto-coupler in case Vcc=12V. Driving LED SE1052 provides direct driving pins to Red and Green LED’s for charging applications. During charging, SE1052 will turn on Red LED. When the charging is completed, SE1052 will turn on Green LED. Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 5 Start Up and Short Circuit Conditions Under start-up or short-circuit conditions the SE1052 does not have a high enough supply voltage. This is due to the fact that the chip has its power supply line in common with the power supply line of the charger system. Consequently, the current limitation can only be ensured by the primary PWM module, which should be designed accordingly. If the primary current limitation is considered not to be precise enough for the application, then a sufficient supply for the SE1052 has to be ensured under any condition. It would then be necessary to add some circuitry to supply the chip with a separate power line. This can be achieved in numerous ways, including an additional winding on the transformer. The following schematic shows how to realize a low-cost power supply for the SE1052 (with no additional windings). Please pay attention to the fact that in the particular case presented here, this low-cost power supply can reach voltages as high as twice the voltage of the regulated line. Since the Absolute Maximum Rating of the SE1052 supply voltage is 18V, this low-cost auxiliary power supply can only be used in applications where the regulated line voltage does not exceed 9V. Vout+ To primary Vcc Rs 1.210 V SE1052 Output Cs R2 Rout Rvc1 C2 22 p F Vctrl 100mV Cic1 2.2nF Rled 1K Ric1 10mV Cvc1 2.2nF R1 Red Ictrl Vsense Rsense GND Green LED_R LED_G Ric2 Note：0 ohms of Ric2 is recommended for LED charging indication function. Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 6 Vout- OUTLINE DRAWING SOP-8 1 8 2 7 3 6 4 5 D B N DIM B1 A1 E H C A A A1 B B1 C D H E DIMENSIONS INCHES MM MIN MAX MIN MAX 0.0532 0.0688 0.0040 0.0098 0.0130 0.0200 0.050 BSC 0.0075 0.0098 0.1890 0.1968 0.2284 0.2440 0.1497 0.1574 OUTLINE DRAWING DIP-8 Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 7 1.35 1.75 0.10 0.25 0.33 0.51 1.27 BSC 0.19 0.25 4.80 5.00 5.80 6.20 3.80 4.00 Customer Support Seaward Electronics Incorporated – China Section B, 2nd Floor, ShangDi Scientific Office Complex, #22 XinXi Road Haidian District, Beijing 100085, China Tel: 86-10-8289-5700/01/05 Fax: 86-10-8289-5706 Seaward Electronics Corporation – Taiwan 2F, #181, Sec. 3, Minquan East Rd, Taipei, Taiwan R.O.C Tel: 886-2-2712-0307 Fax: 886-2-2712-0191 Seaward Electronics Incorporated – North America 1512 Centre Pointe Dr. Milpitas, CA95035, USA Tel: 1-408-821-6600 Last Updated - 5/7/2009 Revision 5/7/2009 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 8