网络变压器培训2.pdfVIP

Wurth Electronics Midcom Inc Mai 10 AR 1 The field Wurth focus on DFM Safety in transformer EMI consideration when design transformer New material and product What Wurth Midcom focus on Transformers • Less than 100W unless • Freq 500kHz • Current 20A - Using Parallel Windings • Low voltage offline (Vin 300V or 400VDC) • Dielectric = 4.5kV for offline • Safety Agencies - IEC60950 and IEC61558-2-17 Custom Inductor • PFC Coil • Shape core buck inductor • Common mode choke with shape core Capability but not focus on Toroid inductor • Limited High Turns Capacity • Wire Size to 15AWG • Special Winding Techniques Difficult to Duplicate Amongst Many Operators Foils Winds and Foil Shields • Rule of Thumb is an Extra Dime per Foil Tubing Eliminates any Possibility of High Speed Auto Winding and Termination Product in the future Planar transformer • 250 Watts • 150 Watts • Transformers for tube light • 20 Watts • 30 Watts Design for manufacturability Pinout Wire size vs. number of strands Coil build Electrical specification / tolerance Shelf tape and insulated wire (introduced in safety) DFM - Pinout Wire crossing – heat damage, potential difference Wire in core window Wire windows Wire on shelves Solder bridging A pinout change may be the easiest fix to many mfg. problems, however, once presented to a customer, it is difficult to change. Pinout – Wire crossing Pinout – Core Window Pinout – Wire Window Inner windings on inner terminals will reduce wire windows and often reduced lead-out length to coil. Pinout – Wire on Shelves