Self current-balancing power supply circuit with multiplexed output

Abstract

The present invention relates to a multi-output self-balancing power circuit. In one embodiment, a multi-output self-balancing power circuit can include: a transformer formed by a primary winding and n (e.g., greater than 2) series connected secondary windings; n output circuits corresponding to the n secondary windings, where each of the n output circuits can include a rectifier diode and a filter capacitor, and a load can be parallel coupled with the filter capacitor; n output circuits series coupled between a first output terminal of a first secondary winding and a second output terminal of an nth secondary winding; and (n-1) current balancing capacitors coupled between a common junction of n secondary windings and a common junction of n output circuits.

Description

technical field [0001] The invention relates to a power supply circuit with multiple outputs, in particular to a self-balanced current power supply circuit with multiple outputs. Background technique [0002] At present, when LEDs are used in occasions requiring high-power and high-brightness lighting, multiple LEDs are often used in combination. The brightness of an LED is directly related to the current flowing through it: in general, the more current flowing through the LED, the brighter it will be. In order to achieve the brightness balance of multiple LEDs, multiple LEDs are usually connected in series, and the primary side control flyback circuit is used as the power supply circuit for LED driving. The schematic block diagram is as follows figure 1 As shown, the switching action of the switching tube Q1 is controlled by detecting the primary side current, and then the current flowing through the LED string is controlled. However, this topology can only drive a single...

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Problems solved by technology

Although this implementation method achieves current sharing between multiple LED loads through a current sharing transformer and a DC blocking capacitor, since a current sharing transformer needs to be added between every two adjacent secondary windings, the implementation is relatively complicated, and the corresponding The cost of the circuit and the volume of the circuit increase accordingly, and the reliability of the entire circuit is low. Due to the increase of the leakage inductance of the circuit caused by the current equalizer, voltage spikes may appear on the diode in the rectification circuit, resulting in an increase in the withstand voltage of the diode.

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