DC-DC CONVERTER CONTROL CIRCUITS I OUTPUT SWITCHFIXED VOLTAGE 15V I 2%REFERENCE ACCURACY I LOWQUIESCENTCURRENT: 15UA(TYP.) I OPERATINGFROM20V TO 200V I FREQUENCYOPERATIONTO 80KHz I ACTIVECURRENT LIMITING DESCRIPTION The U301X series is a monolithic control circuit delivering the main functions for DC-DC voltageconverting. The device contains an internal temperature compensated reference, comparator, duty cycle controlled oscillator with an active current limit circuit, driver and high current output switch. Output voltage is fixed 15V ,integrated two external resistors with a 2% referenceaccuracy. Employingaminimumnumberofexternal components the U301X devices series is designedforStep-Down applications. DIP-8 SO-8 TYPICAL Application CIRCUIT TYPICAL OUPUT CURRENT TABLE(1) Part Number DCM (2) CCM (3) U3012S260mA 300mA U3012D300mA 400mA APPLICATIONS l Electric- Vehicle, Electric- Bicycle Apliance l Industry Controls Product Summary VIN20 200V IO 300mA VOUT15V Work Tem -40 150C U3012 Data Sheet DC-DC CONVERTER CONTROL CIRCUITS U3012_VJ11E 20 200V 15V Pin Configuration Block Diagram Pin Description Pin Number Pin Name I/O Description 1 VINI The VCC power supply for the U301XX Family and the feedback for the circuit. For the normal operation, a capacitor with 1uF is recommended connected to this pin. 5 Drain I The Power MOSFET Drain. 7 GND I/O The ground reference for the IC. Ordering Information Part Number Description SOP- 8, Halogen free in T increase the value of CVIN and decrease the RST, re- do the calculation of above equation until ideal start- up performance is got. For better noise immunity, its recommended that the VIN capacitor be placed as close as possible to the VIN Pin. l Freewheeling Diode (D1) Diode D1 should be an ultra- fast type. Slow diode is not acceptable, because the inductor is always working in continuous conduction mode during start- up period. Slow diode will cause high current spike which will falsely make the Power MOESFET turned off and prevent the output voltage reach regulation. Slow diode will also cause extra power loss and make the efficiency lower down. A 100V/1A diode with recovery time 0.8A forU3012D. l Output Capacitor (COUT) The selection of output capacitor is determined by the requirement of the output voltage ripple. To make the output ripple small enough, a large value of COUT is needed. But large value of COUT will increase the cost and need longer time for soft- start. Typically a capacitor with 100uF/35V is recommended. l Pre- Load Resistor (RL) At no load condition, the switching frequency is determined by the value of CVIN and the operation current of the IC not by the output voltage information. Combined with the value of the selection of inductor L1, theres a minimum input power for this circuit. To keep the regulation of the output voltage at no load condition, a minimum load current is needed. For 15V application, a resistor with value around of 30k ohm is recommended. Table 1 shows the relationship between these circuit parameters and the key operation performance. Table 1 Start- up Time Output Ripple No Load RST CVIN L COUT U3012 Data Sheet DC-DC CONVERTER CONTROL CIRCUITS U3012_VJ11E Package Dimension e D E E1 L C b A2 A A1 SOP8 Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min A 1.350 1.750 A 1.350 A1 0.100 0.250 A1 0.100 A2 1.350 1.550 A2 1.350 b 0.330 0.510 b 0.330 c 0.170 0.250 c 0.170 D 4.700 5.100 D 4.700 e 1.270（BSC） 0.050（BSC） e 1.270（BSC） E1 5.800 6.200 E1 5.800 E 3.800 4.000 L 0.400 1.270 L 0.400 0 8 0 U3012 Data Sheet DC-DC CONVERTER CONTROL CIRCUITS U3012_VJ11E Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 3.710 4.310 0.035 0.047 A1 0.510 0.020 A2 3.200 3.600 0.126 0.142 B 0.380 0.570 0.015 0.022 B1 1.524(BSC) 0.060(BSC) C 0.204 0.360 0.008 0.014 D 9.000 9.400 0.354 0.370 E 6.200 6.600 0.244 0.260 E1 7.320 7.920 0.288 0.312 e 2.540(BSC) 0.100(BSC) L 3.000 3.600 0.118 0.142 E2 8.400 9.000 0.331 0.354 U3012 Data Sheet DC-DC CONVERTER CONTROL CIRCUITS U3012_VJ11E U3012 Data Sheet DC-DC CONVERTER CONTROL CIRCUITS U3012_VJ11E Taiwan Head Office Add. : 8/F-2, No.504, Yuanshan Road, Zhonghe City, Taipei Country 235, Taiwan, R.O.C. Tel. : 886-2-32345737 Fax. : 886-2-32347322 Email : salesuni- Hong Kong Office Add. : Unit 1103B, Tower 2, 11/F., Cheung Sha Wan Plaza, 833 Cheung Sha Wan Road, Hong Kong. Tel. : 852-35908190 Fax. : 852-21846141 Email : salesuni- ADDRESS:www.uni- China Head Office(国内总办事处) 深圳公司联系方式: 地址：深圳市，南山区，西丽镇，留仙大道，鼎新大厦，1208-1210 电话：189 6955 0959/1810585 5985 0755-26615661 传真：0755-26615680 邮箱：hatawal 深圳公司联系方式: 地址：深圳市，南山区，西丽镇，留仙大道，鼎新大厦，1208-1210 电话：189 6955 0959/1810585 5985 0755-26615661 传真：0755-26615680 邮箱：hatawal