Control circuit, control method, driving circuit and lighting device

Abstract

The invention discloses a control circuit, a control method, a driving circuit and a lighting device, and relates to the field of circuit load control. The control circuit includes: a control unit, (n-1) switching units connected in series; the negative polarity end of the first controlled current source in the n controlled current sources is connected to a common ground terminal, and the positive polarity ends of the other (n-1) controlled current sources are correspondingly connected to the negative electrodes of the (n-1) switch units through one one-way switch respectively; the one-way switch is configured to block current between the corresponding switch unit and the controlled current source; the negative polarity ends of the (n-1) controlled current sources are connected to the common ground terminal; the control ends of the n controlled current sources and the control ends of the (n-1) switch units are respectively connected to the control unit; wherein n is an integer and is greater than or equal to 2. Therefore, the continuity / smoothness in the switching process between different LED array combinations is enhanced.

Description

technical field [0001] The present application relates to the technical field of drive circuits, in particular to the technical field of control circuits for solid-state light emitters, and relates to a control circuit, a control method, a drive circuit and a lighting device. Background technique [0002] Light-emitting diode (LED) refers to a semiconductor element that can reflect light of various colors through a PN diode light source composed of a compound semiconductor. This light-emitting element has the advantages of long life, miniaturization and weight reduction, low-voltage driving, and the like. In addition, this light-emitting diode is highly resistant to shock and vibration, and does not require warm-up time and complicated driving. LEDs can be packed in substrates or LED frames in various forms, so they can be patterned into various Application, applied to backlight unit (backlight unit) or various lighting devices, etc. [0003] Use light-emitting diodes to p...

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Problems solved by technology

Furthermore, it is known that the rectified voltage of the power grid spans the interval of (0, maximum value), and the number of LED voltage groups that are turned on is the same as the number of current sources that control the conduction current. If higher efficiency is to be satisfied, A larger number of segments is required, which complicates the circuit structure and leads to higher cost

[0008] Furthermore, because the electrical characteristics of LEDs in different LED groups may also be inconsistent, the conduction voltage drop or conduction threshold of LEDs is not completely constant, but changes with changes in operating temperature, operating current, etc., so This is difficult to calculate. The characteristics between the voltage of the LED string and the current of the LED lack a simple, accurate, and quantitative correspondence. In order to ensure that the power supply voltage before and after switching between different LED groups can be sufficient to drive the LED string, it is often necessary When the power supply voltage is greater than the conduction voltage drop of the LED string and there is enough margin, the switching action is performed to switch different LED strings into or out of the power supply circuit. This switching with sufficient margin will cause Efficiency is reduced, and switching is usually instantaneous, which also brings large electromagnetic interference (EMI)

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