Use of a rectified image voltage for controlling the switch on the primary side of a switched-mode power supply
First Claim
1. A switched-mode power supply, comprising:
- a primary side and a secondary side, a transformer with a primary winding, a secondary winding and an auxiliary winding, of which the primary winding and the auxiliary winding are connected to the primary side and the secondary winding is connected to the secondary side, a switch element connected to the primary winding for interrupting a current flowing in the primary winding, a freely oscillating circuit for generating switching pulses to the switch element, a rectifying and charge storing coupling between the terminals of the auxiliary winding for generating an image voltage, which on the primary side represents a certain voltage of the secondary side, and a coupling from said rectifying and charge storing coupling to said freely oscillating circuit for controlling, on the basis of the value of said image voltage, how switching pulses are generated.
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Accused Products
Abstract
A switched-mode power supply has primary and secondary sides, and a transformer (M1) with a primary winding, a secondary winding and an auxiliary winding. The primary winding and the auxiliary winding are connected to the primary side, and the secondary winding is connected to the secondary side. A switch element (T3) is connected to the primary winding in order to interrupt a current flowing in the primary winding. The switched-mode power supply contains a freely oscillating circuit (R5, C3, R7, T1, T2, R8, R9, R10, R11) for generating switching pulses to the switch element (T3). A rectifying and charge storing coupling (D4, C5) is connected between the terminals of the auxiliary winding in order to generate such an image voltage which on the primary side represents a certain voltage of the secondary side. The switched-mode power supply further contains a coupling (D3, R9) from said rectifying and charge storing coupling (D4, C5) to said freely oscillating circuit (R5, C3, R7, T1, T2, R8, R9, R10, R11) in order to control how switching pulses are generated on the basis of the value of said image voltage.
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Citations
8 Claims
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1. A switched-mode power supply, comprising:
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a primary side and a secondary side, a transformer with a primary winding, a secondary winding and an auxiliary winding, of which the primary winding and the auxiliary winding are connected to the primary side and the secondary winding is connected to the secondary side, a switch element connected to the primary winding for interrupting a current flowing in the primary winding, a freely oscillating circuit for generating switching pulses to the switch element, a rectifying and charge storing coupling between the terminals of the auxiliary winding for generating an image voltage, which on the primary side represents a certain voltage of the secondary side, and a coupling from said rectifying and charge storing coupling to said freely oscillating circuit for controlling, on the basis of the value of said image voltage, how switching pulses are generated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification