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US 5,703,764 AGranted
Switched-mode power supply having standby operation
AssigneeDeutsche Thomson-Brandt GmbH
InventorsWolfgang Hermann, Jean-Paul Louvel
Life of this patent
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Abstract
An integrated circuit achieves a burst mode standby operation for a switched-mode power supply by driving a switching transistor. One winding of a transformer is connected to inputs of two differently biased rectifier circuits and the sum of the output voltages of these circuits is applied to a control terminal of the integrated circuit.
Claims8
A switched-mode power supply having standby operation with a burst mode, comprising:
- a transformer including a primary winding and a secondary winding,
- a switching transistor coupled in series with said primary winding,
- an integrated circuit for controlling said switching transistor,
- a first rectifier circuit coupled to a terminal of a third transformer winding and generating a control voltage for said integrated circuit,
- a second rectifier circuit providing a voltage of opposite polarity with respect to said first rectifier circuit and having a time constant which is appreciably shorter than a time constant of the first rectifier circuit, and
- the outputs of the two rectifier circuits being coupled together to produce a sum voltage, the sum voltage being coupled to a control input of the integrated circuit for inhibiting operation of the integrated circuit in case of a standby condition periodically caused by an overshooting at a time depending upon the time constant of the first rectifier circuit.
3 more elements
Dependencies are inferred from the claim text.