FLYBACK CONVERTER OUTPUT VOLTAGE STABILIZATION.

The expression of the flyback converter output voltage (output power) is derived as a function of the supply voltage, load resistance, transformer ratios, transistor current gain, and base-circuit resistor value. The switching period and duty cycle are also calculated. A converter circuit having stabilized output voltage with respect to supply voltage at constant load is designed. The transistor base current is controlled by the supply voltage, by means of a nonlinear circuit. This feedforward circuit approximates with logarithmic characteristics the ideal hyperbolic dependence of the transistor base current as a function of the supply voltage. The converter has high performance and low cost. A cheaper circuit variant is presented, in which the high-voltage control transistor was eliminated.