H01F 30/04
Fixed transformers not covered by group h01f19/00: having two or more secondary
Official title: having two or more secondary windings, each supplying a separate load, e.g. for radio set power supplies
H01F30/04 (Fixed transformers not covered by group h01f19/00: having two or more secondary) appears on 138 US grants and 152 published applications in this corpus.
Search patents in H01F- Granted patents
- 138
- Published applications
- 152
- Assignees
- 119
- Inventors
- 312
- Latest grant
- 7 Jul 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 2 | 0 |
| 1991 | 0 | 0 |
| 1992 | 2 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 1 |
| 2002 | 1 | 0 |
| 2003 | 2 | 3 |
| 2004 | 0 | 5 |
| 2005 | 3 | 10 |
| 2006 | 5 | 9 |
| 2007 | 13 | 8 |
| 2008 | 9 | 17 |
| 2009 | 7 | 14 |
| 2010 | 9 | 13 |
| 2011 | 13 | 3 |
| 2012 | 4 | 4 |
| 2013 | 4 | 3 |
| 2014 | 0 | 6 |
| 2015 | 3 | 5 |
| 2016 | 8 | 3 |
| 2017 | 6 | 5 |
| 2018 | 2 | 9 |
| 2019 | 9 | 5 |
| 2020 | 5 | 12 |
| 2021 | 6 | 4 |
| 2022 | 8 | 1 |
| 2023 | 5 | 2 |
| 2024 | 2 | 2 |
| 2025 | 2 | 5 |
| 2026 | 4 | 3 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Transformer-based light-source driving systems7 Jul 2026US 12,677,361 B2O2Micro, Inc.
- Display device comprising transformer comprising core having structure related with coupling factor of inductor9 Jun 2026US 12,651,553 B2Samsung Electronics Co., Ltd.
- Low-EMI transformer14 Apr 2026US 12,603,221 B2Ezone Energy AS
- Multiple-port bidirectional converter17 Mar 2026US 12,580,491 B2Lite-On Singapore Pte. Ltd.
- Transformer and method of generating multiple multiphase output signals4 Nov 2025US 12,462,974 B2The Boeing Company
- Dynamic power flow controller (dpfc) for regulating power flow in a power transmission line25 Jun 2026US 2026/0178063 A1
- A transformer arrangement30 Apr 2026US 2026/0120944 A1Hitachi Energy Ltd
- Multiport transformer and integrated high voltage and low voltage converter29 Jan 2026US 2026/0031264 A1Delta Electronics (Thailand) Public Co., Ltd.
- Integrated transformer and inductor assembly with fractional windings11 Dec 2025US 2025/0378987 A1
- Transformer-based light-source driving systems27 Nov 2025US 2025/0365830 A1O2Micro, Inc.
Most cited
By later US patents
- Power supply system199US 7,514,818 B2Matsushita Electric Works, Ltd. · 2009
- High voltage switch with isolated power80US 10,607,814 B2Eagle Harbor Technologies, Inc. · 2020
- High voltage switch with isolated power55US 10,896,809 B2Eagle Harbor Technologies, Inc. · 2021
- Modular multi-pulse transformer rectifier for use in symmetric multi-level power converter55US 8,279,640 B2TECO-Westinghouse Motor Company · 2012
- DC transformer with an output inductance integrated on a magnetic core thereof and a DC/DC converter employing the same30US 7,375,607 B2Hon Hai Precision Industry Co., Ltd. · 2008