DN06007/D Design Note – DN06007/D Wide Input Range (20 Vdc to 140 Vdc) DC to DC Converter Device Application Input Voltage Output Power Topology I/O Isolation NCP1031 Industrial 20 to 140 Vdc 2.5 W Flyback Yes Other Specifications Output Voltage Ripple Nominal Current Max Current Min Current Output 1 Output 2 Output 3 Output 4 5.0 Vdc (1%) 100 mV 180 mA 180 mA 50 mA 12.0 Vdc (5%) 100 mV 100 mA 100 mA 10 mA N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A PFC (Yes/No) No Minimum Efficiency 55% Operating Temp Range -10 to +60 °C Circuit Description Key Features The 2.5 W dc to dc converter utilizes the NCP1031 monolithic controller (U1) in a discontinuous mode flyback converter. An optional EMI filter comprised of C1, C11, and L1 is also included. A simple, isolated voltage feedback scheme is implemented with zener Z1 and optocoupler U2 to control the feed back pin of U1 and regulate the 5 V output. The flyback transformer (T1) utilizes a “stacked” winding configuration for the 12 V output to improve its cross regulation. Input under- and over- voltage shut down can be configured by selecting the correct values for R6, 7 and 8 (see NCP1031 data sheet on onsemi.com). y Very wide range input: 20 to 140 Vdc. July 2006, Rev. 0 www.onsemi.com y Monolithic PWM controller with 200 V MOSFET y Dual outputs with “stacked” windings y Input EMI filter y Extremely simple design with few components y 200 kHz switching frequency 1 DN06007/D Schematic WIDE RANGE INPUT, 2.5 W DC-DC CONVERTER L1 + 10 uH, 250 mA T1 C1 10 nF 200V R1 10K, 0.5W 2.2nf, 1kV C2 47 uF 200V D1 MUR110 47 D4 1N4148 U1 R7 5 1 3 8 C10 1nF C11 2.2 nF "Y" cap U2 C9 10uF C8 10nF 0.1 50V R2 1.5K 7 3 2 8 7 4 2 C5 + 12V, 100mA output D3 MBR150 4 NCP1031 6 R8 5 6 R5 R6 470 uF 25V C4 1 C3 20 to 140 Vdc Input D2 MUR110 C6 1000uf 6.3V C7 0.1 50V + 5V, 180mA output Com 1N5229B Z1 (4.3V) R3 68 opto R4 180 NOTES: 1. Crossed lines on schematic are not connected. 2. U2 is Vishay SFH6156A-4 optocoupler or similar. 3. R6, R7, and R8 set input OV and UV trip points. See NCP1031 data sheet to determine values. 4. Z1 sets 5V output voltage (Vout = Vz + 0.9V approximately.) 5. C1, C11, and L1 are for EMI compliance (optional). 6. C10 sets switching frequency to 200 kHz. 7. See magnetics design sheet for T1 details. July 2006, Rev. 0 www.onsemi.com 2 DN06007/D 1 Magnetics Design Data Sheet Part Description: 3 watt, 200 kHz dual output flyback transformer Schematic ID: T1 Core Type: Ferroxcube EF16 (E16/8/5); 3C95 material or similar Core Gap: Gap for 85 - 100 uH Inductance: 90 uH nominal Bobbin Type: 8 pin horizontal mount for EF16 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Vcc/Boost (2 - 3) 13 turns of #28HN spiral wound over 1 layer. Insulate with mylar tape for 250V min. insulation to next winding. Primary (1 - 4) 24 turns of #28HN over 1 layer. Insulate for 1.5 kV to the next winding with mylar tape. 5V/12V Secondary (7 - 8, 5 - 6) (stacked winding) 6 turns of two different color strands of #28HN bifilar wound with two additional turns with one of the colors (8 total). This will be the 12V winding. The winding should be centered on the primary with 2 mm end margins 9approximately.) Terminate as shown in the schematic below with the 8 turn (12V) winding terminating to pins 5 & 6 and The 5V winding (6 turns) terminating to pins 7 & 8. Hipot: 1.5 kV from Vcc boost & primary to secondary Lead Breakout / Pinout Schematic (Bottom View - facing pins) 1 5 Pri - 24T 4 12V sec - 8t 3 2 1 6 4 7 3 Vcc - 13T 2 5 6 7 8 5V sec - 6T 8 Suggested prototype vendor: Mesa Power Systems Escondido, CA 1-800-515-8514 1 © 2006 ON Semiconductor. Disclaimer: ON Semiconductor is providing this design note “AS IS” and does not assume any liability arising from its use; nor does ON Semiconductor convey any license to its or any third party’s intellectual property rights. This document is provided only to assist customers in evaluation of the referenced circuit implementation and the recipient assumes all liability and risk associated with its use, including, but not limited to, compliance with all regulatory standards. ON Semiconductor may change any of its products at any time, without notice. Design note created by Frank Cathell, e-mail: [email protected] July 2006, Rev. 0 www.onsemi.com 3