Pulse transition time modulation power converter

A PTTM (Pulse Transition Time Modulation) power converter comprising:

• a. a signal input means for supplying a pulse width modulated signal to vary the voltage across a load;
• b. a PWM to PTTM converter having an input, two drive output terminals, and a control output terminal, the input terminal is supplied with said pulse width modulated signal;
• c. first and second transistor drivers each having an input and an output, their inputs are connected to the drive outputs of said PWM to PTTM converter;
• d. a DC voltage source having first and second voltage rails;
• e. first and second switching transistors each having a control electrode and a pair of output electrodes wherein two of said output electrodes are joined to form an output and said control electrodes are connected to the outputs of said first and second transistor drivers;
• f. a power transformer having its primary connected to the joined output of first and second transistors;
• g. a first series resonant capacitor connected in series with the primary winding of said power transformer;
• h. first and second synchronous rectifier transistors each having a control and two output electrodes wherein two of the output electrodes are joined to form a first output terminal;
• i. a second resonant capacitor connected to the output of said first and second switching transistors:
• j. a drive transformer having its primary connected in series with said second resonant capacitor;
• k. a controlled capacitance connected between the output of first and second transistors and second DC supply rail, said controlled capacitance having a control input connected to the control output of said PWM to PTTM converter;
• l. an output capacitor connected to the center tap of the secondary winding of the power transformer, to form a second output terminal, and to the first output terminal;
• m. a load connected across said first and second output terminals.