Semiconductor light-emiting element driver circuit and light fixture using the same

A technology of light-emitting elements and lighting devices, which can be applied to lighting devices, electrical components, electroluminescent light sources, etc., and can solve problems such as large output fluctuations

Inactive Publication Date: 2012-10-24
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the discontinuous mode, although dimming lighting in the low-brightness range is relatively easy to realize, in the high-brightness range to medium The problem of large changes in

Method used

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  • Semiconductor light-emiting element driver circuit and light fixture using the same
  • Semiconductor light-emiting element driver circuit and light fixture using the same
  • Semiconductor light-emiting element driver circuit and light fixture using the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0026] figure 1 It is a circuit diagram of a lighting device for a semiconductor light emitting element according to Embodiment 1 of the present invention. The input DC power supply 1 is composed of a filter circuit 1a, a rectification circuit 1b, and a step-up chopper circuit 1c, which rectifies and smooths the commercial AC power supply Vs, and outputs an approximately constant input DC voltage Vdc. The control power supply circuit 2 is, for example, composed of a step-down chopper circuit using an IPD element (refer to later-described Figure 4 ) configuration to step down the input DC voltage Vdc to generate the control power supply voltage Vcc.

[0027] The DC-DC converter 3 is a step-down chopper circuit (buck converter) composed of a switching element Q1, an inductor L1, a regenerative diode D1, and a smoothing capacitor C1. The switching element Q1 is turned on (ON) and turned off (OFF) at a high frequency. ), so as to output the input DC voltage Vdc after voltage co...

Embodiment approach 2

[0040] figure 2 It is a circuit diagram of Embodiment 2 of this invention. In this embodiment, it is more specifically expressed figure 1 The current detection circuit 5b, the feedback control circuit 6, and the high-frequency oscillation circuit 7 are configured.

[0041] "About High Frequency Oscillating Circuit 7"

[0042] The high-frequency oscillation circuit 7 is composed of general-purpose timer circuits TM1, TM2 and their peripheral circuits. The first timer circuit TM1 is an astable multivibrator that sets the on-off frequency of the switching element Q1, and the second timer circuit TM2 is a monostable multivibrator that sets the on-pulse width of the switching element Q1. device.

[0043] Timer circuits TM1, TM2 are with image 3 For a well-known timer IC (so-called 555) with the internal structure shown in (a), for example, the μPD5555 of Renesas Electronics (under the jurisdiction of the former NEC Electronics) or its dual version (μPD5556) or their substitu...

Embodiment approach 3

[0076] image 3 (b) has shown the main part structure of Embodiment 3 of this invention. In this embodiment, by figure 2 In the shown second embodiment, the voltage of the fifth pin of the first timer circuit TM1 is made variable in the low luminance range, and the frequency of the high-frequency on-off operation of the switching element Q1 is made variable.

[0077] In order to perform dimming and lighting to obtain an extremely weak light output as described above, it is advantageous that the frequency of the high-frequency on-off operation of the switching element Q1 is reduced as it approaches the dimming lower limit.

[0078] exist figure 2 In the preferred embodiment, since the voltage of the fifth pin of the first timer circuit TM1 is fixed, the frequency of the high-frequency on-off operation of the switching element Q1 is fixed. In contrast, in image 3 In the modified example shown in (b), the series circuit of the resistor Ro and the switching element Q3 is co...

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Abstract

To provide a lighting device for a semiconductor light-emitting element adapted to allow stable achieve dimmed lighting ranging from a very minute optical output to rated lighting to be achieved by use of a switching power source operating in a discontinuous mode. [Means for Settlement] A device for dimmed lighting of a semiconductor light-emitting element 4 by use of a DC-DC converter 3 operating in the discontinuous mode includes a burst dimming control part for intermittently stopping an ON/OFF operation of a switching element Q1, thereby adjusting a current flowing to the semiconductor light-emitting element 4, output detecting parts 5a, 5b for detecting at least one of the current flowing to the semiconductor light-emitting element 4 or a voltage applied to the semiconductor light-emitting element 4, and a feedback control part 6 for adjusting an ON period or a burst dimming control period of the switching element Q1 during the ON/OFF operation so that a detected value of the output detecting parts 5a, 5b approaches a target value. In the vicinity of a dimming control lower limit, power supply to the feedback control part 6 may be stopped.

Description

technical field [0001] The present invention relates to a lighting device of a semiconductor light emitting element such as a light emitting diode (LED), and a lighting fixture using the lighting device. Background technique [0002] According to Patent Document 1 (U.S. Patent No. 7,071,762), an LED lighting device that converts power from an input DC power supply using a switching power supply to supply DC current to LEDs is proposed. A solution to dimming LEDs by intermittently stopping burst (burst) dimming control. Furthermore, a detection value of the current flowing through the LED is also proposed, and a feedback control is performed while intermittently stopping the high-frequency operation of the switching power supply at a low frequency (refer to claim 20 and FIG. 11 of this document). [0003] Patent Document 1: US Patent No. 7,071,762 (Claim 20, FIG. 11 ) [0004] The technical problem to be solved in the present invention [0005] The technology of Patent Doc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02H05B44/00
CPCH05B33/0848H05B33/0815H05B45/14H05B45/375H05B45/385H05B45/3725H05B45/39H05B45/38
Inventor 江崎佐奈平松明则
Owner PANASONIC CORP
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