18-07-2013 дата публикации
Номер: US20130181635A1
The disclosed switching regulator, including a controller for a switching regulator, is adaptable to supplying, or controlling the supply of, regulated current to a load that is isolated from a source of input power by a flyback transformer, and includes: (a) detecting, after transistor SW, a zero crossing ZCD corresponding to a primary side switching node voltage Vdecreasing to the input voltage Vin, which occurs after a secondary current Iis substantially zero and before the next SW; (c) establishing a time-integral window T-I_W with a leading edge corresponding to SWand a trailing edge corresponding to ZCD; and (d) modulating at least the time SWFrelative to SWbased on the primary peak current Iat SWand the time-integral window, such that a regulated load current is supplied to the load. 1. A circuit for controlling a switching regulator including a flyback transformer with primary and secondary windings and a switching transistor coupled to the primary side winding at a switching node SW , and configured to supply regulated current to a load that is isolated from a source of input power by the flyback transformer , the circuit comprising{'sub': ON', 'OFF', 'P', 'ON', 'PP', 'OFF', 'S', 'SP', 'OFF', 'ON, 'controller circuitry configured to switch the transistor on at a time SW and off at a time SW, such that a primary current Ithrough the primary side winding increases from substantially zero at SWto a primary peak current Iat SW, thereby inducing in the secondary side winding a secondary current Ithat decreases from a peak current Iat SWto substantially zero before the transistor is switched on at a next SW, in accordance with discontinuous conduction mode operation;'}{'sub': OFF', 'SW', 'IN', 'ON, 'a zero crossing detect circuit configured to detect, after SW, a zero crossing ZCD corresponding to a voltage Vat the primary side switching node SW decreasing in magnitude to an input voltage V, which occurs after the secondary current k is substantially zero and ...
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