Transistor drive circuit
AssigneeReliance Electric Company
InventorHarold J. Brown
Life of this patent
Estimating the term…
Abstract
A drive current circuit for a switching power transistor which allows the controlled turn off of the transistor without affecting transistor turn on. The drive transformer has two cores one of which follows a linear magnetization characteristic and the other of which has a relatively high permeability. The input and output windings of the drive transformer are wound on both cores. A turn off winding is also included which is wound only on the high permeability core. A source of turn off charge is directly coupled to the transistor. Shorting of the turn off winding initiates the controlled turn off of the transistor.
Claims16
A bipolar transistor drive and control circuit comprising:
- (a) a DC charge means directly coupled to said transistor for providing a source of charge for turn off of said transistor;
- (b) a transformer having both a high permeability magnetic core and a low permeability linear magnetic core said transformer also having input and output drive current means said input drive means receiving a drive current signal and said output drive means being connected to both said charge means and said transistor;
- and
- (c) turn off control winding means acting only on said high permeability core.
A drive and control circuit for a bipolar transistor comprising:
- (a) means directly coupled to said transistor for providing a source of charge for turn off of said transistor said means having a substantially constant voltage at least during said turn off;
- and
- (b) a drive transformer having both a low permeability linear magnetic core, and a high permeability magnetic core said transformer including:
- (i) an input winding for receiving a drive current of alternating polarity;
- (ii) an output winding connected between said source and said transistor;
- and
- (iii) a turn off winding wound only on said high permeability core.
A drive and control circuit for a bipolar transistor having a base, an emitter and a collector, said circuit comprising:
- (a) a reverse DC charge means having positive and negative terminals said positive terminal being directly connected to said emitter;
- and
- (b) a transformer having both a high permeability magnetic core and a low permeability linear magnetic core said transformer including:
- (i) input means for receiving a drive current of alternating polarity;
- (ii) output means connected between said base and said charge means negative terminal;
- and
- (iii) turn off control winding means associated with said high permeability core.
Dependencies are inferred from the claim text.