Apparatus for controlling LED string

A control device, N-type technology, applied in lighting devices, lamp circuit layout, use of semiconductor lamps, etc., can solve the problems of discontinuous instantaneous current, dark brightness, bright brightness of front-end LED, etc., to achieve fast opening and closing, reduce EMI interference, the effect of continuous input current

Inactive Publication Date: 2013-12-18
JINONE
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  • Abstract
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AI Technical Summary

Problems solved by technology

However, the turn-on voltages of several high-voltage NMOSs have process differences and temperature changes, so it is difficult to control the switching time and current
As a result, the current at the moment of LED turn-on may be too large or the current disappears for too long, resulting in optical flicker (Flicker)
Moreover, there will be discontinuity and excessive instantaneous current when the total current is open.
[0004] In addition, when driving a long string of LEDs in the traditional way, the front-end LEDs are brighter due to the longer average turn-on time, while the tail-end LEDs are shorter and the brightness is darker; the so-called 120Hz optical ripple
The efficiency of driving high-voltage LEDs in traditional methods is also poor
If more control nodes are added to improve efficiency, it will increase the trouble of production cost

Method used

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  • Apparatus for controlling LED string
  • Apparatus for controlling LED string
  • Apparatus for controlling LED string

Examples

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Embodiment Construction

[0052] figure 1One of the preferred embodiments of the control device for high-voltage LEDs of the present invention is shown. The small LED string 70 has five LED units 701-705, and each LED unit includes several LEDs. The control device includes 5 corresponding high-voltage N-type components (HV NMOS) HV1-HV5, 5 low-voltage current limiting switches (or constant current switches) 21-25 and an external master-slave control in sequence from high potential to low potential Device 51. "External" or "built-in" in this specification is relative to the low-voltage current-limiting switch.

[0053] The current input end of the LED string 70 is connected to an AC power source 901 and a bridge rectifier 902 . The small LED string 70 can be a part of a long LED string, and the control device can also control the corresponding small LED string in series.

[0054] In the small LED string 70 , the current output terminal of each LED unit is connected to the drain of the corresponding ...

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Abstract

The present invention provides an apparatus for controlling an LED string. In the apparatus, each high voltage (HV) N-type device has one end electrically connected or coupled with the corresponding LED unit and the other end coupled with a corresponding low voltage (LV) current limit switch via a corresponding path. The LV current limit switch is switched according to the voltage or current detected on the path. Since the current flowing through the HV N-type device increases or decreases with that flowing through the corresponding LV current limit switch, the HV N-type device will be indirectly controlled.

Description

technical field [0001] The present invention controls high-voltage LEDs through the combination of low-voltage current-limiting switches and high-voltage N-channel components, which can simplify the layout process and reduce production costs; not only effectively reduce the 120Hz optical flicker phenomenon produced by traditional high-voltage LEDs, Can improve electrical efficiency. Background technique [0002] Long strings of high-voltage LEDs are becoming cheaper to produce and are widely used by the public. However, there are still shortcomings to be improved in the way of high pressure control. For example, USP No. 6989807, USP No. 7439944 or USP No. 7081722 have exposed the problems of the switching time point and the driving current being a fixed current. [0003] To solve the above problems, China Taiwan Patent Publication No. 201134293 proposes an integrated circuit for driving high-voltage light-emitting diode bulbs. see it figure 1 and figure 2 , the device ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02H05B44/00
CPCH05B45/48H05B45/39Y02B20/30
Inventor 王弘宗蓝耀辉彭元佑
Owner JINONE
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