US4870554A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Active snubber forward converter
Assignee: POWER SYSTEMS Inc 45 GRIFFIN ROAD SOUTH BLOOMFIELD CT 06002 A CT CORP
•
Filing: 1987-11-12
•
Granted: 1989-09-26
•
Expires: 2007-11-12
Abstract
Abstract In a forward converter power supply comprising a transformer having a primary winding connected to a primary circuit and a secondary winding connected to a secondary circuit, and a switching transistor in the primary circuit, an active network snubber in the primary circuit for receiving and storing continuing current from the transformer primary winding upon switching of the transistor and for returning current through the transformer primary winding so as to resent the transformer and thereby returning parasitic energy in the transformer caused by leakage inductance and magnetizing current to the energy source. The snubber comprises a capacitor for receiving and storing continuing current from said primary winding upon switching of the transistor, a diode for providing a path for flow of the continuing current from the primary winding to the capacitor and an electronic switch operatively connected to the capacitor to the primary winding and to the switching transistor for returning current from the capacitor to the primary winding upon further switching of the transistor. The capacitor is connected so that the voltage thereon automatically adjusts to reset the transformer upon the further switching of the transistor. The electronic switch and the switching transistor are operatively connected in a manner so as to be always in opposite conducting states.
Inventors
- 👤 Jerry J. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:00
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33538
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
97 words
A forward converter power supply comprising: (a) a transformer having a primary winding connected to a primary circuit including a pair of input terminals adapted for connection to an energy source and a secondary winding connected to a secondary circuit including a pair of output terminals; (b) a switching transistor in said primary circuit; and (c) an active network snubber in said primary circuit for resetting said transformer upon switching of said transistor so as to return parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source through the primary winding.
Claim 2
Dependent Claim
97 words
A forward converter power supply comprising: (a) a transformer having a primary winding connected to a primary circuit including a pair of input terminals adapted for connection to an energy source and a secondary winding connected to a secondary circuit including a pair of output terminals; (b) a switching transistor in said primary circuit; and (c) an active network snubber in said primary circuit for resetting said transformer upon switching of said transistor so as to return parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source through the primary winding.
Claim 3
Dependent Claim
50 words
A power supply according to claim 1, wherein said active network snubber comprises: (a) means for receiving and storing continuing current from said transformer primary winding upon switching of said transistor; and (b) electronic switch means for returning current to said transformer primary winding upon further switching of said transistor.
Claim 4
Dependent Claim
92 words
A power supply according to claim 1, wherein said active network snubber comprises: (a) energy storage means for receiving and storing continuing current from said primary winding upon switching of said transistor; (b) means for providing a path for flow of said continuing current from said primary winding to said energy storage means; and (c) an electronic switch operatively connected to said energy storage means to said primary winding and to said switching transistor for returning current from said energy storage means to said primary winding upon further switching of said transistor.
Claim 5
Dependent Claim
30 words
A power supply according to claim 3, wherein said electronic switch and said switching transistor are operatively connected in a manner so as to be always in opposite conducting states.
Claim 6
Dependent Claim
42 words
A power supply according to claim 3, wherein said energy storage means comprises a capacitor, said electronic switch comprises a transistor and said path providing means comprises a diode connected between said primary winding and said capacitor and across said electronic switch.
Claim 7
Dependent Claim
44 words
A power supply according to claim 3, wherein said energy storage means comprises a capacitor connected so that the energy thereon from connection of the input terminals to said energy source automatically adjusts to reset said transformer upon said further switching of said transistor.
Claim 8
Dependent Claim
24 words
A power supply according to claim 1, wherein said active network snubber is connected to said switching transistor and across said transformer primary winding.
Claim 9
Dependent Claim
119 words
A forward converter power supply comprising: (a) a transformer having a primary winding connected to a primary circuit including a pair of input terminals adapted for connection to an energy source and a secondary winding connected to a secondary circuit including a pair of output terminals; (b) a switching transistor in said primary circuit; and (c) an active network snubber in said primary circuit for receiving and storing continuing current from said transformer primary winding upon switching of said transistor and for returning current through said transformer primary winding so as to reset said transformer upon further switching of said transistor thereby returning parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source.
Claim 10
Dependent Claim
119 words
A forward converter power supply comprising: (a) a transformer having a primary winding connected to a primary circuit including a pair of input terminals adapted for connection to an energy source and a secondary winding connected to a secondary circuit including a pair of output terminals; (b) a switching transistor in said primary circuit; and (c) an active network snubber in said primary circuit for receiving and storing continuing current from said transformer primary winding upon switching of said transistor and for returning current through said transformer primary winding so as to reset said transformer upon further switching of said transistor thereby returning parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source.
Claim 11
Dependent Claim
92 words
A power supply according to claim 8, wherein said active network snubber comprises: (a) energy storage means for receiving and storing continuing current from said primary winding upon switching of said transistor; (b) means for providing a path for flow of said continuing current from said primary winding to said energy storage means; and (c) an electronic switch operatively connected to said energy storage means to said primary winding and to said switching transistor for returning current from said energy storage means to said primary winding upon further switching of said transistor.
Claim 12
Dependent Claim
30 words
A power supply according to claim 9, wherein said electronic switch and said switching transistor are operatively connected in a manner so as to be always in opposite conducting states.
Claim 13
Dependent Claim
42 words
A power supply according to claim 9, wherein said energy storage means comprises a capacitor, said electronic switch comprises a transistor and said path providing means comprises a diode connected between said primary winding and said capacitor and across said electronic switch.
Claim 14
Dependent Claim
24 words
A power supply according to claim 8, wherein said active network snubber is connected to said switching transistor and across said transformer primary winding.
Claim 15
Dependent Claim
44 words
A power supply according to claim 9, wherein said energy storage means comprises a capacitor connected so that the energy thereon from connection of the input terminals to said energy source automatically adjusts to reset said transformer upon said further switching of said transistor.
Claim 16
Dependent Claim
151 words
An active network snubber for use in a forward converter power supply including a transformer connected to an energy source and having primary and secondary windings and a switching transistor operatively connected to said primary winding, said snubber adapted for connection across said primary winding and to said switching transistor and comprising: (a) an electronic switch having a current flow path therethrough; (b) a capacitor connected to the current flow path of said electronic switch; and (c) diode means connected to said capacitor and across said electronic switch; (d) so that upon switching of said transistor continuing current from said primary winding flows through said diode means to said capacitor for charging same and thereafter said electronic switch returns current to said primary winding to reset said transformer when said transistor switches again thereby returning parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source.
Claim 17
Dependent Claim
151 words
An active network snubber for use in a forward converter power supply including a transformer connected to an energy source and having primary and secondary windings and a switching transistor operatively connected to said primary winding, said snubber adapted for connection across said primary winding and to said switching transistor and comprising: (a) an electronic switch having a current flow path therethrough; (b) a capacitor connected to the current flow path of said electronic switch; and (c) diode means connected to said capacitor and across said electronic switch; (d) so that upon switching of said transistor continuing current from said primary winding flows through said diode means to said capacitor for charging same and thereafter said electronic switch returns current to said primary winding to reset said transformer when said transistor switches again thereby returning parasitic energy in said transformer caused by leakage inductance and magnetizing current to the energy source.
Claim 18
Dependent Claim
33 words
An active network snubber according to claim 14, wherein said electronic switch and said switching transistor are adapted for operative connection in a manner so as to be always in opposite conducting states.
Claim 19
Dependent Claim
41 words
An active network snubber according to claim 14, wherein said capacitor is connected so that the energy thereon from connection of the input terminals to said energy source automatically adjusts to reset said transformer upon said further switching of said transistor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |