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 46 W isolated flyback power by the transformer leakage inductance. The RCD primary clamp also supply with a single-stage power factor correction circuit for LED reduces radiated and conducted EMI. lighting applications. It provides an accurately regulated 80 V, 580 mA In order to provide line overvoltage detection, the bulk capacitor output for multi-LED-string applications where a post regulator is voltage is sensed and converted into a current by the INPUT used − such as in RGBW smart-lighting fixtures. The design is also VOLTAGE pin resistors R4 and R45. The INPUT VOLTAGE pin line ideal for single string applications as it also provides a constant overvoltage threshold current (I ) determines the input overvoltage 580 mA output current with accurate regulation and no line-induced OV- shutdown point. ripple across a load-voltage range of 80 V to 20 V. The circuit is highly efficient offering accurate load regulation and is stable over The LYTSwitch-6 IC is self-starting, using an internal high-voltage line (90 VAC to 265 VAC). The circuit also delivers a PF of greater current source to charge the PRIMARY BYPASS pin capacitor (C11) than 0.9 with less than 20% A-THD (measured at 230 VAC). when AC is first applied. During normal operation the primary-side circuitry is powered from an auxiliary winding on transformer T2.
Input Stage
A value of 4.7 mF was selected for the BPP capacitor (C11) to select Fuse F1 provides open-circuit protection which isolates the circuit increased-current-limit operation. During normal operation the from the input line in the event of catastrophic component failures. output of the auxiliary (bias) winding is rectified using diode D7 and Varistor RV1 clamps any voltage spikes to protect the circuitry located filtered using capacitor C10. Resistor R18 limits the current being after the fuse from damage due to overvoltage caused by a line supplied to the PRIMARY BYPASS pin. transient or surge. Bridge diode BR1 rectifies the AC line voltage and provides a full-wave rectified DC voltage across the input film capacitors
Power Factor Correction Stage
C2 and C3. The EMI filter is a 2-stage LC circuit comprising C1, L2, The Power Factor Correction circuit comprises an inductor (T1) in C2, L3, and C3 and suppress differential and common mode noise series with blocking diodes (D1 and D17) and is connected to the generated from the PFC and flyback switching stages. DRAIN pin of the LYTSwitch-6 IC. High PF is achieved using a Switched Val ey-Fill Single Stage PFC (SVF S2PFC) circuit operating in
Primary Flyback Stage
discontinuous conduction mode (DCM). In DCM the switched current The bulk capacitor C4 completes the input stage. It filters the line from inductor T1 shapes the input current waveform to create a ripple voltage and provides energy storage. This component also quasi-sinusoid when the rectified voltage on C3 is less than the DC filters differential current, further reducing conducted EMI. The input voltage on C4, this results in a high power factor. stage provides a DC voltage to the flyback converter. One end of the primary winding of transformer (T2) is connected to the positive During switch on-time, energy is stored in the PFC inductor (T1) and terminal of the bulk capacitor (C4) while the other is connected to the the leakage inductance of the flyback transformer (T2). During DRAIN pin of the integrated 650 V power switch in the LYTSwitch-6 switch off-time, the energy from both the PFC and flyback inductors IC (U1). A low-cost RCD primary clamp made up of D8, R46, R17 and is transferred to the secondary-side through the flyback transformer C9 limits the voltage spike developed across the switch that is caused T2. Diode D16 isolates the rectified AC input on C3 from C4 and
9
Rev. K 06/20 www.power.com Document Outline Product Highlights Description Output Power Table LYTSwitch-6 Functional Description Primary Controller Secondary Controller 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