欢迎光临格烁照明官方网站!
十年品牌 值得信赖!
全国咨询电话:15322427999
当前位置:首页 > LED驱动电源技术

Arrow Lighting Solution – AC/DC TRIAC dimming LED driver for

文章出处:8gled.com作者:格烁光电发表时间:2018-07-23
山东代孕-产子频道51HI【贴近生活】

Abstract:

One major application of led lighting is to replace all existing traditional lamp socket. As in order to do so, one key ELement where LED lamp fixture has to fulfill is to dim by traditional Triac and transistor dimmer. In this article, application solution for retrofit lighting replacement suggested by NXP, TI and NS will be presented, and this solution can easily designed to fit with Cree MPL and XPE LED which focus on indoor lighting application.

Triac Dimmer Operation:

Figure 1 demonstrated the internal components and configuration of a traditional Triac dimmer.

Fig.1 Dimmer configuration Fig.2 Dimmer with bulb with L/C filter

The Triac dimmer operation started by the RC circuit, R1, R2 and C1. This RC network control the delay time of the Triac until the voltage C1 reaches the trigger level. The resistance of the potentiometer increase the turn on delay which decrease the on time or the conduction angle of triac. Thus reduce the average power deliver to the load, which is the LED driver.

Traditional dimmer works well with resistive load, such as incandescent lamp. The lamp provides resistive damping to the L-C filter, and its resistance provides holding current to the thyristor.

Many fluorescent, CFL, and LED drivers are not capable to use with the dimmer because it is not able to cope with the sudden rise of voltage late in the half cycle, or the reduced average voltage. Many drivers directly rectify the incoming AC and apply the resulting pulsed DC to capacitive filters. Current is drawn from the source during a very short period at the peak of the incoming voltage waveform, and no current is drawn during the remainder of each half cycle.

Here below demonstrates the LED driver solution suggested by NXP, TI and NS for retrofit lighting with dimmer operation.

NXP triac dimmer compatible LED driver solution - SSL2101

As to better compile of conventional dimmer, NXP SSL2101 introduce a circuitry intended for mains dimmer compatibility. This circuit contains two current sinks that are called bleeders. A strong bleeder is used for zero-cross reset of the dimmer and TRIAC latching. A weak bleeder is added to maintain the hold current through the dimmer.

The strong bleeder switch is switched on when the maximum voltage on pin WBLEED and SBLEED is below the Vth(SBLEED) level (52 V typically). The weak bleeder switch is switched on as soon as the voltage on pin ISENSE exceeds the Vth(high)(ISENSE) level (-100 mV typically). The weak bleeder switch is switched off when the ISENSE voltage drops below the Vth(low) (ISENSE) level (-250 mV typically). The weak bleeder switch is also switched off when the strong bleeder switch is switched on.

Similar to other NXP power supply controller, SSL2101 also implemented valley switching for increasing efficiency as well as reduction in EMI signature. Meanwhile, SSL2101 also implement various types of protection for enhancing reliability and safety.

The SSL2101/2102 12 W LED driver is a solution for a professional application with multiple high power LEDs that requires galvanic isolation and a safe output voltage. It is mains dimmable for both forward phase (Triac) dimmers, and reverse phase (Transistor) dimmers. It can generate up to 16 W output福建代孕-【好孕事自然来zXts】怀孕频道 power, which is equal to a 100 W incandescent lamp (at 63 Lumen/W).Examples are shelf lighting, down lighting, LED lighting for bathrooms.

Fig.3 NXP SSL2101 demoboard

Fig.4 Arrow lighting SSL2101 LED driver with isolation

Here below introduce a new SSL2101 LED driver solution for Cree MPL LED for indoor lighting application:

Technical Features of SSL2101 12W demoboard – MPL LED

Input Voltage: 90V-264V optimized for 120V or 230V

Output Voltage: 30Vmax

Output current:500mAAdjusted by Dimmer

Max power:12W

Efficiency:78% or above

Power Factor:0.9 or above

Dimming Range:0% to 100%

Isolation:4KV

For higher power rating application, designer can consider SSL2102 which integrates a MOSFET with lower Rds(on). These controllers are also capable for non-isolated buck and isolated opto-coupler free flyback topology.

TI SN0901026 (TPS92210) Triac dimmer compatible LED driver solution

SN0901026 is a Green mode flyback controller from Texas Instrument. It operates at peak current and frequency modulation for optimized efficiency. To further increase the efficiency of power converter, It operates resonant valley turn on for reduced EMI and switching loss. Meanwhile, cascoded configuration of this controller can further reduce the switching loss of the MOSFET. Figure 5 shows a schematic of SN0901026 (TPS92210) in 10W Triac dimmable application.

Fig.5 TI Triac dimmable 10W LED driver solution

One major advantage of this solution is the power factor and efficiency of this solution is high, Meanwhile, compare with competitor, this solution is isolated from AC to DC where it can classified in higher categories of safety standard. Electrical testing data are summarized in Table 1.

PF

Efficiency

Harmonic

Iout

90V

0.998

79.7%

5.85%

353mA

115V

0.997

83.5%

5.02%

357mA

220V

0.985

84.5%

4.27%

356mA

264V

0.968

85.3%

5.08%

358mA

Table 1: Electrical testing figures of 10W SN0901026

This solution can further elaborate to higher power rating up to 25W, reduce into a low cost 7W edtion. Texas Instruments and Arrow lighting solution introduces 7W, 10W 25W solution for retrofit application with Triac dimming. Because SN0901026 (TPS92210) carry external MOSFET. Therefore, the power rating of the LED driver can adjust the MOSFET and passive components rating.

NS LM3445 Triac dimmer compatible LED driver solution

This section introduces a controller from National Semiconductor, LM3445 which able to take AC input and capable dim by AC with good linearity. LM3445 enable LED lighting designer driving multi lamp through single dimmer. Meanwhile, to compile IEC1000-3-2 harmonic standard. This solutions also employs PPFC valley fill to reduce the overall harmonic distortion (PF>0.9 at full bright).

Fig. 6 NS LM3445 AC/DC Triac dimmable LED driver circuit schematic

In Fig.6, power factor correction is achieved by valley fill circuit which it is a kind of passive power factor correction. It allows the buck regulator draws power from input line with a larger portion of AC cycle which enables PF>0.9 when full dim on. Meanwhile, it allows the buck converter to operate as fire angle of Triac Dimmer is small, so as to avoid 120Hz flicker.

Fig.7 demonstrated the schematic of multiple driver application circuitry. In Retrofit application with Triac dimmer compatible, it is always require to control multiple LED driver by a single dimmer. In order to do so, this controller allows one or more LM3445 devices or PWM LED driver devices (slaves) to be controlled by a single LM3445 (master) by connecting their DIM pins together.

By placing two series diodes on the Master VCC circuit one forces the master VCC UVLO to become the dominant threshold. When Master VCC drops below UVLO, GATE stops switching and the RC timer (>200 us) rises above the TL431 threshold (2.5V) which in turn pulls down on the gate of the Slave pass device.

Fig. 7 Master Slave LM3445 circuitry

Fig.8 10W demoboard

Other retrofit Application Circuitry:

References:

1) Datasheet of LM3445, National Semiconductor, 29 Mar 2009

2) Application note of SSL2101, AN10754, NXP, 30 Jan 2009

3) Datasheet of SN0901026, Texas Instruments, Feb 2009


山东代孕-产子频道51HI【贴近生活】 Arrow Lighting Solution – AC/DC TRIAC dimming LED driver for原创编辑请注明出来http://www.yzxinfa.com

排行榜

最新资讯文章