SE1052

Description SE1052 is a highly integrated solution for SMPS applications requiring CV (constant voltage) and CC (constant current) modes. It also has built-in LED drivers specifically designed for stand-alone Battery Charging applications. SE1052 integrates three voltage references, three operational amplifiers, and two current sensing circuits together in the same IC. The 1st voltage reference, together with one operational amplifier, controls the output voltage. The 2nd voltage reference, together with another operational amplifier, senses and limits the amount of the current on the low side, hence the overall current at the output. The 3rd voltage reference and operational amplifier senses when the charging current drops to 10% of the programmed value. During charging, SE1052 will turn on Red LED. When the charging is completed, SE1052 will turn on Green LED. The SE1052 is available in SOP8 and DIP8 package. Features Constant Voltage and Constant Current Control Low Voltage Operation Precision Internal Voltage References Low External Component Count Current Sink Output Stage Easy Compensation Low AC Mains Voltage Rejection Rugged 1.5KV ESD withstand capability. Internal 2 LED drivers Available in SOP8 and DIP-8 Package. RoHS Compliant and 100% Lead (Pb)-Free Application Adapters Digital Camera Chargers. Cellphone Chargers. Other Battery Chargers Ordering Information Device Package SOP8 and VOUT Fixed output voltages 1.21V Pin Configuration SOP8 T View op Green Output GND Vctrl 1 2 3 4 8 7 6 5 Red Ictrl Vsense Output Vcc GND Vctrl 3 4 6 5 Vsens e Vcc 2 7 Ictrl Green DIP8 Top View 1 8 Red SE1052 DIP8 (Lead-free) Pin Description Name Green VOUT GND VCTRL VCC VSENSE ICTRL Red Pin# 1 2 3 4 5 6 7 8 Type Driver Current Sink Output Power Supply Analog Input Power Supply Analog Input Analog Input Driver Function Turning on Green LED when the charging is completed. Output Pin. Sinking Current Only Ground Line. 0V Reference For All Voltages Input Pin of the Voltage Control Loop Positive Power Supply Line Input Pin of the Current Control Loop Input Pin of the Current Control Loop 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 Absolute Maximum Rating Symbol VCC VIN θJA TJ TSTG TLEAD DC Supply Voltage Input Supply Voltage Thermal Resistance Junction to Ambient Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering 10 Sec) Parameter Maximum 18 -0.3~ VCC 250 0 to 125 -40 to 150 260 Units V V °C/W °C °C °C Electrical Characteristic VCC = 5.0V, TA = 25°C, unless otherwise specified. Symbol Parameter Conditions Total Current Comsuption ICC Total Supply Current - not taking the output sinking current into account ISINK=0 0.7 1.2 2.5 mA Min Typ Max Unit Voltage Control Loop Gmv VREF LRV IIBV VOL IOS Transconduction Gain (Vctrl). Sink Current Only1） Voltage Control Loop Reference Reference Input Bias Current (Vctrl) Low Output Voltage at 10mA Sinking Current Output Short Circuit Current. Output to VCC. Sink Current Only Vctrl=Vcc, Ictrl=Vsense=GND, ISINK=10mA, G and R Pins Open Vctrl=Vout=Vcc, Ictrl=Vsense=GND, G and R Pins Open Current Control loop Gmi VSENSE LRI IIBI VOL IOS Transconduction Gain (Ictrl). Sink Current Only3） Current Control Loop Reference Reference Current out of pin Ictrl at -200mV Low Output Voltage at 10mA Sinking Current Output Short Circuit Current. Output to VCC. Sink Current Only Vsense=Vcc, Ictrl=Vctrl=GND, ISINK=10mA, G and R Pins Open Vsense=Vout=Vcc, Ictrl=Vctrl=GND, G and R Pins Open 15 4） 2） ISINK=0 to 10mA ISINK=0 Vcc= 2.5V to 18V 1.198 2.4 1.21 0.6 70 250 15 24 350 35 1.222 8 mA/mV V mV nA mV mA Linear Regulation of Voltage Control Loop ISINK=0 to 5mA ISINK=0 Vcc=2.5V to 18V 192 7.2 200 0.8 20 250 24 350 35 208 4 mA/mV mV mV uA mV mA Linear Regulation of Current Control Loop 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 Electrical Characteristic VCC = 5.0V, TA = 25°C, unless otherwise specified. Symbol Current Monitor Loop VTH Hys Threshold Voltage of Turning Red Pin from Low to High Hysterisis of the comparator in Current Monitor Loop 20 14 mV mV Parameter Conditions Min Typ Max Unit 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 To primary Vout+ R2 SE1052 1.210V Vcc Output Rout C2 22 pF Rvc1 Cs 100mV Cvc1 2.2nF Rled 1K R1 Vctrl Cic1 2.2nF Ric1 10mV Red Ictrl Vsense GND Ric2 Rsense Green LED_R LED_G Vout- 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 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) Eq1 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. 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. Revision 5/7/2009 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. 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. To primary Vcc Rs 1.210 V Vout+ R2 SE1052 Output Rout C2 22 p F Rvc1 Cvc1 2.2nF Cs 100mV Vctrl Cic1 2.2nF Ric1 Rled 1K LED_R 10mV R1 Red Ictrl Vsense Rsense GND Ric2 Green LED_G Vout- 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 OUTLINE DRAWING SOP-8 1 2 D 8 7 6 B1 B DIM A A1 B B1 C D H E N 3 4 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 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 5 A1 E H A C 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 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