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Led lighting circuit and illuminating apparatus using the same

A technology for lighting circuits and LED modules, applied in the field of solutions, can solve problems such as reference current fluctuations and transistor losses, achieve uniform light output and avoid circuit losses.

Inactive Publication Date: 2009-09-09
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, the above-mentioned method based on the mirror circuit is beneficial to obtain the current balance between the LED load circuits u1 and u2, but there is a problem that the reference current will fluctuate due to the fluctuation of the power supply voltage VDC. The problem of losses occurring in the resistors r23, r24, r20 and transistor q20 of the above reference current

Method used

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  • Led lighting circuit and illuminating apparatus using the same
  • Led lighting circuit and illuminating apparatus using the same
  • Led lighting circuit and illuminating apparatus using the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] figure 1 It is a block diagram showing the configuration of the LED lighting circuit 31 according to the first embodiment of the first aspect of the present invention. In this LED lighting circuit 1 , three LED load circuits U1 to U3 in which a plurality of LEDD1 are connected in series are connected in parallel to form an LED module 32 . The number of LED load segments connected in series in each LED load circuit U1-U3 is arbitrary, and a single LED can also be used.

[0049] In each of the LED load circuits U1 to U3, the LED D1 is mounted on a common heat sink and bonded, and a phosphor for wavelength conversion, a lens for light diffusion, and the like are mounted thereon. The LED module 32 and the LED lighting circuit 31 are used as lighting fixtures, the LED load emits blue light or ultraviolet light, and the wavelength of the light emitted by the LED load is converted by the phosphor to emit white light. The number of parallel circuits of the above-mentioned LE...

Embodiment 2

[0065] Figure 5 It is a block diagram showing the configuration of the LED lighting circuit 71 according to the second embodiment of the first aspect of the present invention. In this LED lighting circuit 71, parts similar to and corresponding to those of the above-mentioned LED lighting circuit 31 are denoted by the same reference numerals, and description thereof will be omitted. It is worth noting that, in the LED lighting circuit 71, the LED module 72 is composed of a plurality of LED load circuits U1', U2',..., Un' connected in series in n segments, and each LED load circuit U1', U2', ..., Un' have, a plurality of LEDs D11, D12, ..., D1m; D21, D22, ..., D2m; ...; Dn1, Dn2, ..., Dnm arranged in parallel with each other and connected in series to form a current mirror Control elements of the circuit Q11, Q12, ..., Q1m; Q21, Q22, ..., Q2m; ...; Qn1, Qn2, ..., Qnm.

[0066] Moreover, the LED with the highest conduction voltage Vf ( Figure 5 D11, D2m, ..., Dn2) as a refer...

Embodiment 3

[0118] Figure 16 It is a block diagram showing the structure of the LED lighting circuit 261 according to the third embodiment of the third aspect of the present invention. In this LED lighting circuit 261, the parts similar to and corresponding to those of the above-mentioned LED lighting circuit 231 are denoted by the same reference numerals, and description thereof will be omitted. It should be noted that, in the LED lighting circuit 261, impedance elements A2, A3 are provided in parallel between terminals of the LED load circuits U2, U3 whose control elements Q2, Q3 are not in the diode structure in the LED module 32b. The impedance elements A2, A3 reduce the impedance of the corresponding LED load circuit U2, U3, and clamp the voltage between the terminals to be lower than the voltage between the terminals of the above-mentioned LED load circuit U1, for example Figure 16 The shown may be constituted by a zener diode, or a structure including a resistance element connec...

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Abstract

The invention provides a LED lighting circuit and illuminating apparatus using the same. Light outputs from many LEDs are uniformized and power consumption required for such uniformizing is suppressed, in an LED lighting circuit to be used for illuminating apparatus and the like. Currents flowing from a DD converter (35) to an LED module (32) are detected by a current detection resistor (R2) and compared with a reference voltage (Vref) from a reference voltage source (38) by a comparison circuit (37). Corresponding to the comparison results, a control circuit (36) controls the DD converter (35), and the currents flowing to the LED module (32) are controlled to be constant currents at the same time. Furthermore, in LED load circuits (U1-U3) configuring the LED module (32), control elements (Q1-Q3) configuring a current mirror circuit are arranged in series, a corresponding control element (Q1) is permitted to have a diode structure by having a circuit (U1) with the highest sum of the LED ON voltages as a reference, the flowing current values of the control elements (Q2, Q3) of the remaining circuits (U2, U3) are interlocked, and the LED load circuits (U1-U3) are balanced.

Description

technical field [0001] The invention relates to an LED lighting circuit and a lighting appliance using the LED lighting circuit, in particular to a scheme for equalizing the current of a plurality of LEDs arranged in parallel. Background technique [0002] When using the above-mentioned LED (light-emitting diode) in the above-mentioned lighting fixtures, when using multiple LEDs to obtain the necessary light output, or LEDs with low current, the chip is subdivided to obtain the same light output with high efficiency. In some cases, an excessive power supply voltage is required to connect these plurality of LEDs in series and to light them. On the other hand, if the plurality of LEDs are connected in parallel and turned on, an excessive current is required. Therefore, in reality, an appropriate series-parallel structure is adopted according to the application. However, when blue LEDs are used, the conduction voltage Vf is about 3 to 3.5V, and the deviation is relatively lar...

Claims

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Application Information

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IPC IPC(8): H05B37/02H01L33/00
Inventor 西野博之盐滨英二
Owner PANASONIC CORP
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