Multipath constant-current driving circuit

Abstract

The invention discloses a multipath constant-current driving circuit comprising a DC / AC converter, a main transformer and at least two rectifying and filtering units, wherein the main transformer comprises at least one auxiliary side winding with a tap; at least two rectifying and filtering units form a power supply loop respectively with the auxiliary side winding of the main transformer; each power supply loop comprises a first rectifying loop and a second rectifying loop which are respectively used for rectifying positive and negative semi-cycle alternating-current voltage; a current-sharing transformer is arranged between neighboring first power supply loop and second power supply loop, and windings of the current-sharing transformer are respectively positioned in the rectifying loopscontained in the first power supply loop and the second power supply loop and are used for current sharing among the different rectifying loops in which the neighboring rectifying and filtering unitsare positioned. The multipath constant-current driving circuit has good current-sharing level, and can reduce the size of the current-sharing transformer and lower the cost.

Description

technical field [0001] The invention relates to the technical field of constant current driving, in particular to a multi-channel constant current driving circuit. Background technique [0002] At present, for LED constant current control driven by multiple LEDs, the most commonly used solution is a constant voltage module + multiple non-isolated DC / DC constant current modules. [0003] Such as figure 1 Shown is an LED constant current control circuit driven by multiple LEDs in the prior art. In this circuit, the input voltage Vac is used as the input of multiple non-isolated DC / DC constant current modules after passing through the constant voltage module, and each non-isolated DC / DC constant current module performs constant current control independently. However, since the voltage of the constant voltage module and the voltage of the LED generally have a large voltage difference, the efficiency of the multi-channel non-isolated DC / DC constant current module in the subsequ...

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Problems solved by technology

However, for figure 2 In the circuit shown, since the two coils of the coupled inductor Lca are connected in series in the DC loop, there is a DC component, and the excitation current in the coupled inductor is unidirectional, so when the voltages of the two load branches are unbalanced, the two The current error of the load branch is large, and the current sharing degree is poor; moreover, when there is a DC component in the coupled inductor, the magnetic core will be saturated and an air gap needs to be opened. Therefore, when the inductance is large, the coupled inductor is large in size and high in cost

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