Resolver exciter having a simple power source unit

A resolver exciter for actuating a resolver, comprising:

• a direct current source;
• a resonance circuit for providing a resonant frequency, said resonance circuit including a transformer having a primary coil connected to said direct current source and a secondary coil for supplying output voltage to said resolver, a capacitor connected in parallel with said primary coil and an impedance adjustment inductor connected in series with said primary coil;
• switching means having a gate terminal and connected between said direct current source and said primary coil;
• a reference voltage generator for providing a reference voltage;
• switch control means for controlling said switching means to change a duty cycle of current supplied to said primary coil, said switch control means including a comparator having an output terminal connected to said gate terminal and first and second input terminals and a triangular wave signal generator connected to said first input terminal of said comparator;
• and
• regulation means, connected between said reference voltage generator and said second input terminal of said comparator, for maintaining said output voltage of said secondary coil at a constant shape by adjusting said duty cycle, wherein
• said regulation means comprises:
• a monitoring coil disposed in said transformer for providing a voltage signal related to said output voltage of said secondary coil;
• difference detecting means having input terminals connected to said monitoring coil and said reference voltage and an output terminal connected to said second input terminal of said comparator, wherein
• said difference detecting means supplies an output signal relative to a difference between said voltage signal of said monitoring coil and said reference voltage to adjust said duty cycle so that said voltage signal of said monitoring coil can equal said reference voltage.