Dc to dc converter with voltage regulation through pulse width modulation by control of the distribution of flux variations in a dual core transformer

Claim 2

A DC to DC converter comprising a first transformer core, a second transformer core, an input winding wound to encircle said first and second cores, an output winding wound to encircle said first core, a voltage monitoring circuit to monitor the voltage output across said output winding, a control winding wound to encircle said second core, a fourth winding wound to encircle both said first and second cores, a pulse delay circuit coupled to said fourth winding with its delay characteristics responsive to said voltage monitoring circuit, a switching device shunting said control winding and responsive to the pulse output of said pulse delay circuit, whereby said pulse output activates said switching device to short said control winding and enable the transmission of signals from said input winding to said output winding by permitting flux variations in said first transformer core and inhibiting flux variations in said second transformer core.

Claim 3

A DC to DC converter as defined in claim 1 wherein said second transformer core comprises a core having square loop magnetization properties and is designed to saturate during alternate half-cycles of periodic input signals applied to said input winding by having a volt-time capacity in excess of the volt-time product of periodic input signals applied to said input winding and said switching device comprises a controlled rectifier responsive to only one polarity of control signal supplied by said pulse delay circuit whereby said transmission of signals from said input winding to said output winding is controlled by said switching device only during alternate half-cycles of periodic input signals applied to said input winding and the said transmission of signals from said input winding to said output winding is controlled by saturation of said second transformer core during intervening half-cycles of periodic input signals applied to said input winding.

Claim 4

A DC to DC converter as defined in claim 1 wherein said voltage monitoring circuit comprises a reference voltage source energized by said output voltage and a voltage error detector to compare the reference voltage and the output voltage and a starting voltage circuit to supply a temporary reference voltage before an output voltage exists to energize said reference voltage source.

Claim 5

A DC to DC converter as defined in claim 3 wherein said starting voltage circuit comprises a capacitor shunting said reference voltage source and a charging path to supply energy from said fourth winding to said capacitor and means to disable said charging path when said reference voltage source becomes operative.

Claim 6

A DC to DC converter comprising a periodic voltage source to generate a periodic voltage having a particular volt-time product, a first transformer core having a square loop magnetization curve And a volt-time product capacity in excess of the volt-time product of said periodic voltage source, a second transformer core having a square loop magnetization curve and a volt-time product capacity in excess of the volt-time product of said periodic voltage source, a primary winding wound to encircle both said first and second transformer cores and connected to said periodic voltage source, said primary winding having a sufficient number of turns to limit flux excursion in said first and second transformer cores to a minor hysteresis loop, a secondary winding wound to encircle said first transformer core, a control winding wound to encircle said second transformer core, a fourth winding wound to encircle said first and second transformer cores, means to monitor the output voltage supplied by said secondary winding, signal delay means responsive to said means to monitor and connected to delay the signal output of said fourth winding, a controlled rectifier having its main conductive path connected in parallel with said control winding and including a control electrode connected to said signal delay means, whereby said controlled rectifier is responsive to control signals of one polarity from said signal delay means derived from the signal output of said fourth winding and shorts said control winding during alternate half-cycles of said periodic voltage source and said second transformer core saturates during the intervening half-cycles of said periodic voltage source.

Claim 7

A DC to DC converter comprising a periodic voltage source to generate a periodic voltage having a particular volt-time product, a first transformer core having a square loop magnetization curve And a volt-time product capacity in excess of the volt-time product of said periodic voltage source, a second transformer core having a square loop magnetization curve and a volt-time product capacity in excess of the volt-time product of said periodic voltage source, a primary winding wound to encircle both said first and second transformer cores and connected to said periodic voltage source, said primary winding having a sufficient number of turns to limit flux excursion in said first and second transformer cores to a minor hysteresis loop, a secondary winding wound to encircle said first transformer core, a control winding wound to encircle said second transformer core, a fourth winding wound to encircle said first and second transformer cores, means to monitor the output voltage supplied by said secondary winding, signal delay means responsive to said means to monitor and connected to delay the signal output of said fourth winding, a controlled rectifier having its main conductive path connected in parallel with said control winding and including a control electrode connected to said signal delay means, whereby said controlled rectifier is responsive to control signals of one polarity from said signal delay means derived from the signal output of said fourth winding and shorts said control winding during alternate half-cycles of said periodic voltage source and said second transformer core saturates during the intervening half-cycles of said periodic voltage source.

Claim 8

A DC to DC converter as defined in claim 5 and including a full wave rectifier connected across said secondary winding, a pair of output terminals connected to said rectifier, said means to monitor the output voltage comprising a source of reference voltage comprising a breakdown diode energized by voltage across said output terminals, and a voltage error detector connected to and responsive to relative magnitudes of the voltage across said output terminals and said reference voltage, said voltage error detector generating an error signal and connected to control said signal delay means, said signal delay means delaying signals in proportion to the magnitude of said error signal.

Claim 9

A DC to DC converter as defined in claim 6 and including a starting circuit comprising a capacitor connected to said voltage error detector and across said breakdown diode and a capacitor charging path interconnecting said fourth winding to said capacitor and a diode to block conduction in said charging path by being biased when said breakdown diode become operative.