| 摘要 |
A circuit configuration for a fixed frequency blocking oscillator converter switching power supply includes an electric switch. A transformer has a primary winding connected in series with the electric switch in the circuit of a voltage source outputting a direct voltage with a first algebraic sign, the switch being alternatingly switched on in a first operating phase and switched off in a second operating phase, and a secondary winding having a voltage from which a rectified output voltage is attained. An integratable trigger circuit for pulse-width-modulated switching of the switch has an oscillator emitting a voltage oscillating periodically between upper and lower peak values, and a pulse width modulator connected between the oscillator and the switch for switching the switch as a function of the periodically oscillating oscillator voltage. The periodically oscillating oscillator voltage varies at a speed being at least intermittently proportional to the direct voltage in a period segment in which its variation over time has the same algebraic sign as the direct voltage.
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