| 摘要 |
1, 021, 811. Automatic voltage control. WESTERN ELECTRIC CO. Inc. Aug. 27,1962 [Sept. 29,1961 (2)], No. 32793/62. Heading G3R. Also in Division H3] A power supply regulating circuit comprises a voltage source 1, a load 2, a series switching transistor 7, and a regenerative feedback network including a transformer 4 which is associated with an inductor 3 and impedance elements 8, 9, 10 to control the periods of conduction and non-conduction of the transistor 7. In operation, a small current initially flows through the collector/emitter path of transistor 7 and the load when the voltage source is applied to the circuit; this current also flows through transformer winding 5, which has a much lower impedance than inductor 3, whereby a voltage is induced in winding 6 tending to drive transistor 7 further into conduction. The current flowing through inductor 3 then increases with time and the current through winding 5 decreases accordingly until transistor 7 is driven out of the saturation region; the current through inductor 3 then starts to decrease, the associated flux collapses, and a current is induced in winding 5 to oppose the load current, the current flowing through the components 9,10 being such as to bias the transistor 7 to cut-off; the cycle will start again when the energy in inductor 3 is dissipated. The "off" time of transistor 7 is controlled by varying the impedance of the elements associated with the winding 6. The series transistor may be controlled in dependence upon output voltage variations (Fig. 3 not shown), and the circuit may include further amplifying and control transistors associated with a further transformer winding (Figs. 4 and 5, not shown). An embodiment including temperature compensating and protective circuits for the series transistor is described with reference to Fig. 6 (not shown). Mechanical or pnpn switches may replace the series transistor as a switching element. |
