Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
268 words
A direct-direct symmetrical convertEr power pack having an input for being coupled to a supply source having a voltage having either one of two predetermined different absolute values and an output and comprising: a converter formed by a transformer having two end terminals, said transformer comprising a winding with a centre tap and further taps; at least one rectifier circuit coupled to said two end terminals of said transformer and comprising an output forming the output of said power pack, a switching circuit comprising first and second terminals, first, second, third and fourth transistors, each having a control electrode and first and second further electrodes, four biasing circuits respectively coupled to said control electrodes of said first, second, third and fourth transistors, said first further electrodes of said first and second transistors being coupled to said first terminal, and said second further electrodes of said first and second transistors being symmetrically coupled to said winding relatively to said centre-tap, said first further electrodes of said third and fourth transistors being coupled to said second terminal and said second further electrodes of said third and fourth transistor being symmetrically coupled to said winding relatively to said centre-tap, said first terminal and said centre-tap forming a first input of said converter, said first and second terminals forming a second input of said converter; and a selector device for connecting said input of said power pack either to said first input or to said second input of said converter depending upon the value of said voltage for maintaining at a constant value the voltage at said output of said power pack.
Claim 2
Dependent Claim
268 words
A direct-direct symmetrical convertEr power pack having an input for being coupled to a supply source having a voltage having either one of two predetermined different absolute values and an output and comprising: a converter formed by a transformer having two end terminals, said transformer comprising a winding with a centre tap and further taps; at least one rectifier circuit coupled to said two end terminals of said transformer and comprising an output forming the output of said power pack, a switching circuit comprising first and second terminals, first, second, third and fourth transistors, each having a control electrode and first and second further electrodes, four biasing circuits respectively coupled to said control electrodes of said first, second, third and fourth transistors, said first further electrodes of said first and second transistors being coupled to said first terminal, and said second further electrodes of said first and second transistors being symmetrically coupled to said winding relatively to said centre-tap, said first further electrodes of said third and fourth transistors being coupled to said second terminal and said second further electrodes of said third and fourth transistor being symmetrically coupled to said winding relatively to said centre-tap, said first terminal and said centre-tap forming a first input of said converter, said first and second terminals forming a second input of said converter; and a selector device for connecting said input of said power pack either to said first input or to said second input of said converter depending upon the value of said voltage for maintaining at a constant value the voltage at said output of said power pack.
Claim 3
Dependent Claim
44 words
A power pack as claimed in claim 1, wherein one of said two predetermined absolute values of said voltage being half the other one, said second further electrodes of said first and third transistors are connected to a single one of said further taps.
Claim 4
Dependent Claim
65 words
A power pack as claimed in claim 1, wherein said first and second transistors are of one and the same type and said third and fourth transistors are of the type complementary to said one type, and wherein said first further electrode, said second further electrode and said control electrode of each of said transistors are respectively the collector, the emitter and the base thereof.
Claim 5
Dependent Claim
40 words
A power pack as claimed in claim 3, wherein each of said four biasing circuits comprises a parallel arrangement of a resistor and a capacitor, each arrangement being connected between the base of one of said transistors and said winding.
Claim 6
Dependent Claim
65 words
A power pack as claimed in claim 1, wherein said selector device is an automatic selector circuit comprising: a first switch between said input of said power pack and said first terminal; a second switch between said input of said power pack and said second terminal; and means coupled to said power pack input, and responsive to the voltage applied thereto, for controlling said switches.