Multiplexed output current equalizing circuit for LED (Light Emitting Diode)
A circuit and current sharing technology, which is applied in the direction of electric lamp circuit layout, electric light source, lighting device, etc., can solve the problems of output current drop and failure to work normally
Active Publication Date: 2012-05-16
INVENTRONICS HANGZHOU
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[0005] However, this circuit has the following disadvantages: when any LED load is opened, the current of the LED load branch is zero, and the voltage on the current sharing bus is only (N-1) / N*Vshare. Since it is powered by a constant current source, The voltage signals on the sampling resistors of all LED load branches are greater than the voltage signals on the current sharing bus, causing the output current to drop until the output current drops below the bias voltage provided by the bias resistor Rb. At this time, the remaining LEDs The LED light of the load branch works in the off or slightly bright state, that is, it cannot work normally
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[0027] In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0028] see figure 2 , which is a schematic diagram of Embodiment 1 of an LED multi-output current equalization circuit provided by the present invention.
[0029] The LED multi-output current sharing circuit provided in this embodiment includes: a constant current source 100, a bus control circuit 400 and at least two LED loads; each LED load corresponds to a current sharing circuit 200 and a current sharing control circuit 300;
[0030] The constant current source 100 is used to convert the input AC power Vac into a constant current to supply power to each LED load;
[0031] Such as figure 2 As shown, it includes n LED loads, namely A1, A2, and An; the output end of the constant current source 100 is connected to the anode of each...
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The invention provides a multiplexed output current equalizing circuit for an LED (Light Emitting Diode). The multiplexed output current equalizing circuit comprises a constant current source, a bus control circuit, at least two paths of LED loads as well as one current equalizing circuit and one current equalizing control circuit which respectively correspond to each path of LED load; the constant current source is used for supplying power; and all LED load branches share one bus control circuit. When all LED load branches are not in open circuit, the current equalization of each LED load branch is realized. When R paths of LED loads are in open circuit, the equalization of total current is realized by current of (N-R) paths of LED loads which are not in open circuit. According to the multiplexed output current equalizing circuit for the LED, which is provided by the invention, after certain LED loads are in open circuit, the realization of current equalization of other LED load branches is ensured and the current of the constant current source is equalized, thereby regular work is realized.
Description
technical field [0001] The invention relates to the technical field of LED current equalization, in particular to an LED multi-channel output current equalization circuit. Background technique [0002] Such as figure 1 The circuit shown is a circuit provided by the Chinese patent publication number CN201550320U, and the title of the invention is "a multi-channel constant current control circuit suitable for LED drivers". [0003] After any current sampling signal VRsn and current sharing bus voltage Vshare are compared and adjusted inside the current sharing control circuit 102, the output signal of the current sharing control circuit 102 can control the impedance of the linear adjustment tube in the corresponding current sharing circuit 101, and then control The magnitude of the current of each channel realizes current sharing; wherein the current sharing bus voltage Vshare is the average voltage signal Vshare=(VRs1+...VRsn) / N of each output current on the sampling resisto...
Claims
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IPC IPC(8): H05B37/02
Inventor 葛良安姚晓莉华桂潮
Owner INVENTRONICS HANGZHOU