12w市电可调光反激电路设计指南

UM10341 SSL2101 12 W mains dimmable LED driver Rev. 01 — 17 September 2009 User manual Document information Info Content Keywords SSL2101, LED driver, AC/DC conversion, dimmable, driver, mains supply, user manual Abstract This is a user manual for the SSL2101 mains dimmable 12 W LED driver demo boards. NXP Semiconductors UM10341 SSL2101 12 W LED driver Revision history Contact information Rev Date Description 01 20090917 First issue UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 2 of 23 For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com NXP Semiconductors UM10341 SSL2101 12 W LED driver 1. Introduction The SSL2101 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 power, which is equal to a 100 W incandescent lamp (at 63 Lumen/W). Examples are shelf lighting, down lighting, LED lighting for bathrooms etc.The design gives an example of how to make a drive that is suitable for small form factor applications like retrofit lamps. 2. Safety warning The board needs to be connected to mains voltage. Touching the reference board during operation must be avoided at all times. An isolated housing is obligatory when used in uncontrolled, non-laboratory environments. Even though the secondary circuit with LED connection has a galvanic isolation, this isolation is not according to any regulated norm. Galvanic isolation of the mains supply using a variable transformer is always recommended. These devices can be recognized by the symbols shown in Figure 1: 3. Connecting the board The board can be optimized for a 230 V (AC) (50 Hz) or for a 120 V (AC) (60 Hz) mains supply. Besides the mains voltage optimization, the board is designed to work with multiple high power LEDs with a total working voltage of between 9 V and 23 V. The output current can be limited using trimmer R20. On request, a dedicated LED load can be delivered that is to be connected to K3. Connector K2 can be used to attach other LED loads. The output voltage is limited to 25 V. When attaching a LED load to an operational board (hot plugging) an inrush peak current will occur due to discharge of capacitor C6. After frequent discharges, the LEDs may deteriorate or become damaged. a. Isolated b. Not Isolated Fig 1. Variac isolation symbols UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 3 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver If a galvanic isolated transformer is used, it should be placed in between the AC source and the dimmer/demo board. Connect a user defined LED (string) to the connector K2 as shown in Figure 2. Note that the anode of the LED (string) is connected to the bottom side of this connector. Remark: When the board is placed in a metal enclosure, the middle pin of connector K1 can be connected to the metal casing for grounding. 4. Specifications Table 1 shows the specifications for the SSL2101 12 W LED driver Fig 2. Board connection diagram Table 1. Specifications Parameter Value Comment AC line input voltage 85 V (AC) to 276 V (AC) Board has been optimized for 230 V (AC) or 120 V (AC) ± 10 % variation Output voltage (LED voltage) 9 V (DC) to 23 V (DC) Output voltage protection 25 V (DC) Output current (LED current) 400 mA to 800 mA Adjustable with trimmer Output voltage /load current dependency < ± 4 % / Volt in regulated range See attached graphs Current ripple ± 150 mA at 500 mA Maximum output power (LED power) 17 W At Vo + 21 V Efficiency 70 % to 78 % At Tamb = 25 °C See Section 13 graphs UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 4 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver 5. Board photos Power Factor: 120 V(AC) 230 V(AC) 0.99 at 15 W output power 0.94 at 15 W output power 0.90 at 11 W output power Switching frequency 60 kHz to 75 kHz - Dimming range 100% to 0% - Board dimensions 103 mm × 50 mm × 20 mm L × W × H Operating temperature 0 °C to 85 °C - Isolation voltage ± 4 KV Between primary and secondary circuit Input voltage /load current dependency +5 % to −6 % in the range of 130 V (AC) to 110 V (AC) - +3 % to −3 % in the range of 250 V (AC) to 210 V (AC) - Table 1. Specifications …continued Parameter Value Comment Fig 3. Demo board (top) UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 5 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver 6. Dimmers Several triac based dimmers have been tested by NXP Semiconductors. As different dimmers have different specifications, the dimming performance of the board may vary. Table 2 shows the range of dimmers that have been tested with the board: Fig 4. Demo board (bottom) Table 2. Dimmer selection Manufacturer Type Voltage V (AC) Power range (W) Load Min. dimming range Opus 852.390 230 60 to 400 Ha/Inc 0.6 % Opus 852.392 230 20 to 500 Inc 0.05 % Bush-Jaeger 2250U 230 20 to 600 Ha/Inc 0.03 % Bush-Jaeger 2247U 230 20 to 500 Ha/Inc 0.07 % Bush-Jaeger 6519U 230 40 to 550 Ha/Inc 8.4 % Gira 1184 230 60 to 400 Inc 1 % Everflourish EFO700D 230 50 to 300 Ha/Inc 0.2 % Drespa 0817 230 20 to 315 Ha/Inc 3.4 % Ehmann 39 Domus 230 20 to 500 Ha/Inc 1 % Drespa 815 230 20 to 500 Inc 1.1 % Lutron TG-600PH-WH 120 600 Inc 0 %(off) Levitron L12-6641-W 120 600 Inc 0 %(off) Levitron L02-700-W 120 600 Inc 0 %(off) Levitron 6602-IW 120 600 Inc 0 %(off) Levitron 6683-W 120 600 Inc 0 %(off) Levitron R12-6631-LW 120 600 Inc 0 %(off) UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 6 of 23 Cooper 6001 120 600 Inc 0 %(off) Lutron MIR-600THW-WH 120 600 Ha/Inc 0.9 % NXP Semiconductors UM10341 SSL2101 12 W LED driver 7. Functional description The IC both controls and drives the flyback converter part, and it ensures proper dimmer operation. Several high voltage switches are integrated in the IC. One of these controls the flyback input power, and is situated between the DRAIN and SOURCE pins. On closing, a current will start to run, which stores energy in the transformer TX1. The switch is opened when the duty factor has exceeded the level set by the PWMLIMIT pin, with a maximum of 75 %, or when the voltage on the SOURCE pin exceeds 0.5 V. Following this, the energy stored in the transformer is discharged to D6 and the output capacitors C5 and C6, and finally absorbed by the load. The converter frequency is set with an internal oscillator, the timing of which is controlled by external RC components on pins RC and RC2. By varying the BRIGHTNESS pin voltage, the oscillator frequency can be modulated to an upper and lower value. The ratio between R15 and R16 sets the frequency variation. The two other switches are called the weak bleeder (pin WBLEED), and the strong bleeder (pin SBLEED). When the voltage on both these pins is below a certain value (typical 52 V) the SBLEED switch closes, providing a current path that loads the dimmer Fig 5. Block diagram SSL2101 ISENSE SBLEED WBLEED BLEEDER SUPPLY LOGIC PROTECTION LOGIC OSCILLATOR FRC Overcurrent Blank Low freq Stop Short-winding protection THERMAL SHUTDOWN POWER - UP RESET PWM LIMIT CIRCUIT VALLEY DRAIN AUX SOURCE 100 mV 0.5 V 1.5 V VCC RC BRIGHTNESS RC2 PWMLIMIT GND 014aaa567 3 4, 5,13, 14, 15 8 6 7 9 10 1 2 16 11 12 UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 7 of 23 during zero voltage crossing. This resets the dimmer timer. When the voltage on either of these pins is above 52 V, and the voltage on the ISENS pin is above -100 mV, the weak NXP Semiconductors UM10341 SSL2101 12 W LED driver bleeder switch closes. Using Q3, this current is boosted and provides a current path that loads the dimmer when the converter draws insufficient current to have the dimmer latching stable. Whilst the strong bleeder will always switch, the weak-bleeder will not activate until the output power drops below 8 W. This happens when the LEDs are dimmed, or when the maximum LED power is tuned below 8 W. See Figure 6 and Figure 7 that show bleeder voltage versus time in dimmed and un-dimmed position (low voltage = active): Fig 6. Dimmed bleeder operation Fig 7. Un-dimmed bleeder operation UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 8 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver This board is optimized to work with a power factor above 0.9. In order to achieve this, the converter operates at constant ton mode. The output power of the converter is buffered by capacitor C6. Due to this configuration, the circuit has a resistive input current behavior in un-dimmed operation (see Input in Figure 7). In dimmed operation however, not only the dimmer latch and hold current must be maintained, but a damper must be added to dampen the inrush current and to dissipate the electric power that was stored in the LC filter within the dimmer. Though at low power ranges (< 10 W) a serial resistor can be used for this, at higher power ranges a single series resistor is not efficient because the converter supply current will cause significant voltage drop and thus dissipation through this resistor. On the demonstration board, a combination of serial resistance and a parallel damper has been chosen to improve efficiency. The serial resistor is made up of F1, R1, R2 and R12. The parallel damper is made of C2 and R3. See Figure 8. The input circuit of the converter must be equipped with a filter that is partially capacitive. The combination of C1, L1, L2, C3 and C4 makes a filter that blocks most of the disturbance generated by the converter input current. A drawback of this filter is a reduction of power factor, due to the capacitive load. A lower converter power in relation to the capacitive value of this filter/buffer will cause a lower power factor. At the 230 V (AC) design using 150 nF capacitors, a power factor of 0.9 is reached at 11 W output power. The board is equipped with a feedback loop that limits the output current. This feedback loop senses the LED current over sense resistor R18 and a current mirror is used, consisting of Q1/Q2. Using R20, the current level can be set. The same feedback loop is also used for overvoltage protection. If the LED voltage exceeds 23 V, a current through R19 and D9 will start flowing. The current through the opto-coupler IC2 will pull down the PWMLIMIT and BRIGHTNESS pin. At a value below 400 mV, the “on”-time is zero. The feedback loop has proportional action only, and the gain is critical because of phase shift caused by the converter and C6. The relation between PWMLIMIT and output current is quadratic in nature. The resulting output current spread will be acceptable for most LED applications. The dimming range is detected by sensing the average rectified voltage. R4, R5 and R17 make a voltage divider, and C9 filters the resulting signal. The converter sets its duty factor and converter frequency accordingly. 8. Board optimization The following modifications can be done in order to meet different customer application requirements: 8.1 Changing the output voltage and LED current Compared to other topologies a flyback converter has the major advantage, is that it is suitable for driving a broader range of output voltages. Essentiality, changing the turns ratio whilst maintaining the value of the primary inductance, will shift the output working voltage accordingly. Part of the efficiency of the driver is linked to the output voltage. A lower output voltage will increase the transformation ratio, and cause higher secondary losses. In practice, a mains dimmable flyback converter will have an efficiency between 80 % for high output voltages (like 60 V) down to 50 % for low output voltages (like 3 V). At low voltages, synchronous rectification might become advisable to reduce losses. The UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 9 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver NXP TEA1791 can be applied for this purpose. For exact calculations of transformer properties and peak current, refer to application note AN10754, “SSL2101 dimmable mains LED driver”, and the calculation tool that goes with it. 8.2 Changing the output ripple current The LED voltage, the LED dynamic resistance and the output capacitor principally determine the output current ripple. The value of C6 has been chosen to optimize capacitor size with light output. A ripple of ± 25 % will result in an expected deterioration of light output < 1 %. The size for the buffer capacitor can be estimated from the following equation As example: For a ripple current of ± 5%, and a mains frequency of 50 Hz, and a dynamic resistance of 0.6 Ω, C6 has to be 20 ÷ (300 × 0.6) = 111 mF. For a ripple current of 25 % and a dynamic resistance of 6 Ω, 4 ÷ (300 × 6) = 2200 μF. Using a series of LEDs, the dynamic resistance of each LED can be added to the total dynamic resistance. 8.3 Adapting to high power reverse phase (transistor) dimmers. Reverse phase (transistor) dimmers differ in two ways that can be beneficial but can also cause problems with dimming detection: • The negative phase-cut (trailing edge) causes no inrush current when the dimmer triggers. At triac dimmers, there will be a sudden voltage difference over the input leading to a steep charge of the input capacitors. The resulting peak current will lead to higher damper dissipation. Because this steep charge is missing, the input capacitors will have less stress, and the input circuit is less prone to audible noise. • Transistor dimmers contain active circuitry that require a load charge during the time that the dimmer is open. The dimensioning of the circuit generating the internal supply voltage inside the dimmer is made critical in order to avoid excessive internal dimmer losses. This means that the remaining voltage drop over the lamp must be low enough to reach this charge. For dimmers like the Busch-Jaeger 6519U, the minimum lamp load is specified at 40 W which is equivalent to a 1.3 kΩ resistor load at 230 V(AC). Such a load would result in highly inefficient operation at low output power levels, since most energy is wasted in order to drive the dimmer, and not to produce light. On the demo board, the weak bleeder value R6/R7 is chosen to minimize losses (about 2 W to 3 W). The weak bleeder normally only switches “on” during dimmed operation. The voltage drop with some transistor dimmers is however not sufficient to cause full dimming range control (minimum 10 % instead of < 1 %), because in this application, the average rectified voltage is used to determine the dimming position. To compensate for the reduced voltage difference, voltage detection can be made more sensitive by replacing R4 with a Zener diode, like the BZV85-C200 for 230 V (AC), or the BZV85-C68 for 120 V (AC) applications. Because of increased sensitivity, the dimming curve will also be steeper when using triac dimmers. C6 IIΔ----- 1 6 fnet Rdynamic⋅ ⋅ -----------------------------------------⋅= UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 10 of 23 NXP Semiconductors UM10341 SSL2101 12 W LED driver 8.4 Changing the load curve The load curve can be divided into two regions: A part where the control loop limits the duty cycle of the converter, and where the output current is regulated, and a part where the duty factor feedback is not dominant anymore. This last part occurs at output voltages below 13 V. In this area, constant output power becomes the dominant control mechanism. Changing the turns ratio of the transformer to match the output load will also change this load curve. 8.5 Multiple driver support It is possible to attach multiple converters to a single dimmer. At the use of triac dimmers the inrush current will rise, though not proportionally to the number of converters. Transistor dimmers are more suitable for usage with multiple converters because the dimming range will increase due to the added bleeder action, and there is no inrush current. UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 11 of 23 xxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x xxxxxxxxxxxxxx xxxxxxxxxx xxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx U ser m anual R ev. 01 — 17 Septem ber 2009 12 of 23 N XP Sem iconductors U M 10341 SSL2101 12 W LED driver 9. B oard schem atic xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxx x x U M 10341_1 © N X P B .V. 2009. A ll rights reserved. Fig 8. Board schematic diagram NXP Semiconductors UM10341 SSL2101 12 W LED driver 10. Bill Of Materials (BOM) Table 3. Bill of materials 230 V (AC) Part No. Ref. Des. Part Value Pwr (W) Tol. (%) Volt (V) Package Type Manuf. Amount 1 K1 Conn 3 pin 2u ang m - - - - SL 5.08/3/90 Weidmuller 1 2 K1' Conn 3 pin 2u f - - - - BL 5.08/3 Weidmuller 1 3 K3 Conn 6 pin 1u f - - - - BL3.36Z Fischer 1 4 K2 Conn 2 pin 2u ang m - - - - SL 5.08/2/90 Weidmuller 1 5 K2' Conn 2 pin 2u f - - - - BL 5.08/2 Weidmuller 1 6 F1 Fusistor 6.8E 1 10 - Free - - 1 7 R1 Resistor 39 Ω 1 5 - Free - - 1 8 R2 Resistor 39 Ω 1 5 - Free - - 1 9 R3 Resistor 1 kΩ 2 5 - Free - - 1 10 R4 Resistor 470 kΩ 0.25 1 - Free - - 1 11 R5 Resistor 470 kΩ 0.25 1 - Free - - 1 12 R6 Resistor 10 kΩ 1 5 200 Free - - 1 13 R7 Resistor 10 kΩ 1 5 200 Free - - 1 14 R8 Resistor 2.2 kΩ 1 5 200 Free - - 1 15 R9 Resistor 2.2kΩ 1 5 200 Free - - 1 16 R10 Resistor 0.4 Ω 1 1 Free - - 1 17 R11 Resistor 33 kΩ 0.25 5 200 Free - - 1 18 R12 Resistor 15 Ω 1 5 200 Free - - 1 19 R13 Resistor 100 kΩ 0.1 1 200 Free - - 1 20 R14 Resistor 22 kΩ 0.1 1 Free - - 1 21 R15 Resistor 470 kΩ 0.1 1 Free - - 1 22 R16 Resistor 4.7 kΩ 0.1 1 Free - - 1 23 R17 Resistor 12 kΩ 0.1 1 Free - - 1 24 R18 Resistor 0.3 Ω 1 1 Free - - 1 25 R19 Resistor 10 kΩ 0.1 5 Free - - 1 26 R20 Resistor 50 kΩ Lin 0.1 5 Horizontal - Bourns 1 27 R21 Resistor 22 kΩ 0.1 1 Free - - 1 28 R22 Resistor 330 Ω 0.1 1 Free - - 1 29 R23 Resistor 470 Ω 0.25 5 Free - - 1 30 R24 Resistor 3.9 kΩ 0.1 5 Free - - 1 31 R25 Resistor 470 kΩ 0.25 5 Free - - 1 32 R26 Resistor 10 kΩ 0.1 5 Free - - 1 33 C1 Capacitor 470 pF - 10 1 K Cer DEBB33A471KC1B Murata 1 34 C2 Capacitor 150 nF - 10 400 Poly NRM-S154K400F NIC 1 35 C3 Capacitor 150 nF - 10 400 Poly NRM-S154K400F NIC 1 UM10341_1 © NXP B.V. 2009. All rights reserved. User manual Rev. 01 — 17 September 2009 13 of 23 36 C4 Capacitor 150 nF - 10 400 Poly NRM-S154K400F NIC 1 37 C5 Capacitor 4.7 μF - 10 63 Poly B32560J475K Epcos 1 NXP Semiconductors UM10341 SSL2101 12 W LED driver 38 C6 Capacitor 2200 μF 105° 10 25 2222 021 16222 Vishay 1 39 C7 Capacitor 4.7 μF 105° 10 25 Free - - 1 40 C8 Capacitor 330 pF - 5 - Cer, Free - - 1 41 C9 Capacitor 10 μF 105° 10 25 Free - - 1 42 C10 Capacitor 2.2 nF - 10 4 K Cer DECE33J222ZC4B Murata 1 43 C11 Capacitor 10 nF - 10 25 Cer, Free - - 1 44 L1 Inductor 680 μH - - - - 744776268 Wurth 1 45 L2 Inductor 330 μH - - - - 744776233 Wurth 1 46 L3 Inductor 100 μH - - - - 74477120 Wurth 1 47 TX1 Transformer N87/ 3F3 - - - EFD25 750340505 Wurth 1 48 D1 Rect. Bridge 2 A - - - SO-4 DBLS205G Taiwan semi 1 49