Datasheet LYTSwitch-6 (Power Integrations) - 9

LYTSwitch-6 Application Example
C12 3.3 nF 250 VAC L3 C16 C18 D16 560 µH 100 µF 100 µF S1J-13-F T2 100 V 100 V
80 V, 580 mA
1 RM10 FL1
TP3
R48 C14 C9 100 Ω 100 pF R29 D1 1000 pF R17 1/2 W 1 kV 102 kΩ C37 ES2_J_LTP 630 V 510 kΩ 1% 1.5 nF 1/8 W 200 V VR1 D10 9 BZD27C200P STTH3R06S 200 V 600 V R4 2 FL2 2.0 MΩ T1 FL4 EE13 R46 VR2 20 Ω BZD27C200P C15 D8 200 V 10 µF DFLR1600-7 25 V 600 V FL3 5 7 D11 R30 DFLU1400-7 1.62 kΩ BR1 1% D17 5 UD4KB100 1/16 W ES2J-LTP 1000 V R22
TP1
47 Ω L2 4 20 mH C2 1 3 C3 220 nF C1 330 nF
90 - 265
RV1 450 V 100 nF 450 V
VAC
275 VAC 630 VDC F1 2 4 C19 3.15 A 330 pF 50 V
TP2
C13 2.2 µF C4 25 V R47 68 µF 4.7 kΩ R45 450 V 2.00 MΩ 1% R24 D7 6.2 Ω DFLR1200-7 1% 200 V
D V FWD SR GND BPS FB CONTROL
R43
VOUT
0.062 Ω 1% R18 1/2 W 10 kΩ
S BPP IS LYTSwitch-6
C10 C11 U4 22 µF 4.7 µF LYT6068C D13 16 V 50 V US1B
RTN
PI-8576-012618
TP4
Figure 10. Schematic DER-657, 46.4 W, 80 V, 0.58 A for Universal External LED Driver Application. The circuit shown on Figure 10 is a 45 W isolated flyback power comprises D8, R46, R17 and C9 limits the voltage spike caused by the supply with a single stage power factor correction circuit for LED transformer leakage inductance across the DRAIN and SOURCE pins lighting application. It is designed to provide a constant voltage of the internal MOSFET of the LYTSwitch-6 IC. The RCD primary supply of 80 V with tight voltage regulation up to 580 mA output clamp also reduces radiated and conducted EMI. current typical y for applications where a post regulator is used for multi-LED string design such as RGBW smart lighting. And for typical The voltage across the bulk capacitor (C4) is sensed and converted single-LED string application it provides a constant output current into current through INPUT VOLTAGE pin resistor (R4 and R45) to with accurate regulation and no line-induced ripple of 580 mA from provide detection of line overvoltage. The OV pin line overvoltage 80 V to 20 V output. The circuit is optimized to operate with high threshold (I ) determines the input overvoltage threshold. OV- efficiency and accurate line and load regulation across an input The LYTSwitch-6 IC is self-starting, using an internal high-voltage voltage range of 90 to 265 VAC, with greater than 0.9 PF and less current source to charge the PRIMARY BYPASS pin capacitor (C11) than 20% A-THD at 230 VAC. when AC is first applied. During normal operation the primary-side
Input Stage
block is powered from an auxiliary winding on the transformer T2. Fuse F1 provides open-circuit protection which isolates the circuit The value of the BPP capacitor C11 used is 4.70 mF for increased from the input line for any catastrophic component failures. Varistor current limit. Output of the auxiliary (or bias) winding is rectified RV1 clamps any voltage spike to a safe level to protect the circuit using diode D7 and filtered using capacitor C10. Resistor R18 limits connected after the fuse from damage due to overvoltage caused by the current being supplied to the BPP pin. a line transient or surge. Bridge diode BR1 rectifies the AC line
Power Factor Correction Stage
voltage to provide a full-wave rectified DC voltage across the input Power factor circuit comprises of inductor (T1) in series with blocking film capacitors C2 and C3. The circuit employed a 2-stage LC EMI diode (D1 and D17) is connected to the DRAIN pin of the LYTSwitch-6 filter comprises of C1, L2, C2, L3, and C3 to suppress differential and IC. High power factor correction is achieved using Switched Val ey- common mode noise generated from the PFC and flyback switching Fill Single Stage PFC (SVF S2PFC) configuration operating in operation. discontinuous conduction mode (DCM). The DCM switched current
Primary Flyback Stage
from inductor T1 shapes the input current in a quasi-sinusoid The bulk capacitor C4 filters the line ripple voltage and provides waveform when the rectified voltage on C3 is less than the DC energy storage to supply DC voltage to the flyback DC-DC stage, voltage on C4, which gives high power factor for line input current. where one end of transformer (T2) primary winding is connected to During MOSFET on-time, energy is being stored in the PFC inductor the positive terminal of the bulk capacitor (C4) while the other side is (T1) and flyback inductor (T2). During MOSFET off-time, the energy connected to the DRAIN pin of the integrated 650 V power MOSFET from both the PFC and flyback inductors is transferred to the of LYTSwitch-6 IC (U1). Capacitor C4 also filters differential current secondary-side through the flyback transformer T2. which reduces conducted EMI noise. A low-cost RCD primary clamp
9
Rev. E 02/18 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description LYTSwitch-6 Functional Description Primary Controller Secondary Controller Application Example Key Applications Design Considerations Primary-Side Components of LYTSwitch-6 Secondary-Side Components of f LYTSwitch-6 Recommendations for Circuit Board Layout Recommended Position of InSOP-24D Package with Respect to Transformer Quick Design Checklist Other Applications Design Example PCB Layout Example Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics Typical Performance Curves InSOP-24D Package Drawing MSL Table ESD and Latch-Up Table Part Ordering Information