초록 ▼

A self-oscillating power-supply circuit includes between two power-supply terminals (1, 2), the series arrangement of the primary winding (n1) of a transformer, a first transistor (T1), a first resistor (R1), and a second series arrangement of the secondary winding (n2) and a first diode (D1), with

A self-oscillating power-supply circuit includes between two power-supply terminals (1, 2), the series arrangement of the primary winding (n1) of a transformer, a first transistor (T1), a first resistor (R1), and a second series arrangement of the secondary winding (n2) and a first diode (D1), with terminals (2, 4) for the connection of a battery (B) and, via a switch (S1), a motor (M). The secondary winding (n2) is connected to the base of the first transistor (T1) via the series arrangement of a second resistor (R2), a first capacitor (C1) and a third resistor (R3), a first zener diode (D2) being arranged between the third resistor (R3) and the first resistor (R1). The ends of the first resistor (R1) are coupled to the inputs (16, 17) of a switching amplifier (15) for turning off the first transistor (T1) at a specific voltage across the first resistor (R1). In order to achieve change-over from a normal charging current to a trickle-charging current at a specific battery voltage and in order to power the motor (M) with a constant voltage which is independent of the load, the circuit further has a switching device including the series arrangement of a fourth resistor (R4), a second transistor (T2) and a fifth resistor (R5), the base of the second transistor (T2) being coupled to the node (6) between the first capacitor (C1) and the second resistor (R2), to which a second diode (D3) is arranged in parallel.

대표청구항 ▼

A power-supply circuit for charging a battery with a charging current, said power-supply circuit comprising, between a first and a second power supply terminal, a first series arrangement of a primary winding of a transformer, a first transistor switch having a control input, and a first resistor, a

A power-supply circuit for charging a battery with a charging current, said power-supply circuit comprising, between a first and a second power supply terminal, a first series arrangement of a primary winding of a transformer, a first transistor switch having a control input, and a first resistor, and a second series arrangement of a secondary winding of the transformer and a first diode, said second series arrangement comprising terminals for connecting a battery; a positive-feedback path between a node interconnecting the secondary winding and the first diode and the control input of the first transistor switch, said positive-feedback path comprising a series arrangement of a second resistor and a first capacitor, the terminal of the first capacitor which is remote from the second resistor being coupled to the cathode of a zener diode; first switching means for turning off the first transistor switch at a specific voltage across the first resistor, said first switching means comprising a first input coupled to that end of the first resistor which is nearest the first transistor switch, a second input coupled to that end of the first resistor remote from the first transistor switch, and an output which is coupled to the control input of the first transistor switch; and second switching means for changing over from the charging current to a trickle-charging current above a specific threshold voltage, characterized in that the anode of the zener diode is coupled to one end of the first resistor, and in that the second switching means comprises a series arrangement of a third resistor, a second transistor switch having a control input, and a fourth resistor, arranged between the first input of the first switching means and the second power supply terminal, the control input of the second transistor switch being coupled to the node between the second resistor and the first capacitor, a third diode being arranged in parallel with the second resistor.