SY5800A

联系人：殷先生 TEL：13380368939 QQ：719307610 Applications Note: SY5800A Single Stage Flyback And PFC Controller With Primary Side Control For LED Lighting Preliminary Specification AN_SY5800A Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 1 General Description The SY5800A is a single stage Flyback and PFC controller targeting at LED lighting applications. It is a primary side controller without applying any secondary feedback circuit for low cost, and drives the Flyback converter in the quasi-resonant mode to achieve higher efficiency. It keeps the Flyback converter in constant on time operation to achieve high power factor. Ordering Information Temperature Code Package Code Optional Spec Code SY5800 □□□□(□□□□□□□□)□□□□ Temperature Code Package Code Optional Spec Code SY5800 □□□□(□□□□□□□□)□□□□ Temperature Range: -40°C to 105°C Features • Primary side control eliminates the opto-coupler. • Valley turn-on of the primary MOSFET to achieve low switching losses • 0.3V primary current sense reference voltage leads to a lower sense resistance thus a lower conduction loss. • Internal high current MOSFET driver: 1A sourcing and 2A sinking • Low start up current: 15µA typical • Reliable short LED and Open LED protection • Power factor >0.90 with single-stage conversion. • Compact package: MSOP10 and SO8 Applications • LED lighting • Down light • Tube lamp • PAR lamp • Bulb Typical Applications Figure 1. Schematic Diagram MSOP10 Ordering Number Package type Note SY5800AFBC MSOP10 ---- SY5800AFAC SO8 ---- SY5800A AN_SY5800 Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 2 Figure 2. Schematic Diagram SO8 联系人：殷先生 TEL：13380368939 QQ：719307610 SY5800A AN_SY5800 Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 3 Pinout (top view) (MSOP10) (SO8) Top Mark: AFDxyz for SY5800AFBC(device code: AFD, x=year code, y=week code, z= lot number code) AFBxyz for SY5800AFAC(device code: AFB, x=year code, y=week code, z= lot number code) Pin Name Pin number SO8 Pin number MSOP10 Pin Description COMP 1 1 Loop compensation pin. Connect a RC network across this pin and ground to stabilize the control loop. NC ---- 2 No connection. ZCS 2 3 Inductor current zero-crossing detection pin. This pin receives the auxiliary winding voltage by a resister divider and detects the inductor current zero crossing point. This pin also provides over voltage protection and line regulation modification function simultaneously. If the voltage on this pin is above VZCS,OVP, the IC would enter over voltage protection mode. Good line regulation can be achieved by adjusting the upper resistor of the divider. ISEN 3 5 Current sense pin. Connect this pin to the source of the primary switch. Connect the sense resistor across the source of the primary switch and the GND pin. (current sense resister RS: REF PSS OUT V N R =k I × , 0.16k = ) GND 4 4 Ground pin DRV 5 6 Gate driver pin. Connect this pin to the gate of primary MOSFET. VIN 6 7 Power supply pin. This pin also provides output over voltage protection along with ZCS pin. EN 7 8 Enable pin. Enable the IC by pulling the voltage on this pin above 1.5V and Shut down the IC by pulling the voltage on this pin below 0.2V. If not used, connect this pin to VIN pin with a resistor (470kΩ is recommended). TM 8 9 Connected to ground. SGND ---- 10 Signal ground. 联系人：殷先生 TEL：13380368939 QQ：719307610 SY5800A AN_SY5800 Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 4 Absolute Maximum Ratings (Note 1) VIN, DRV ---------------------------------------------------------------------------------------------------------------- -0.3V~19V Supply Current IVIN ----------------------------------------------------------------------------------------------------------- 30mA EN, ZCS -------------------------------------------------------------------------------------------------------------------- VIN+0.3V ISEN, COMP, TM -------------------------------------------------------------------------------------------------------------- 3.6V Power Dissipation, @ TA = 25°C MSOP10/SO8 ------------------------------------------------------------------ 0.8W/1.1W Package Thermal Resistance (Note 2) MSOP10/SO8,θ JA -------------------------------------------------------------------------------------------- 125°C/W /88°C/W MSOP10/SO8,θ JC --------------------------------------------------------------------------------------------- 60°C/W /45°C/W Temperature Range ------------------------------------------------------------------------------------------------ -40°C to 150°C Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------------ 260°C Storage Temperature Range -------------------------------------------------------------------------------------- -65°C to 150°C Recommended Operating Conditions (Note 3) VIN, DRV ----------------------------------------------------------------------------------------------------------------- 8V~15.4V Junction Temperature Range ------------------------------------------------------------------------------------- -40°C to 125°C Ambient Temperature Range ------------------------------------------------------------------------------------ -40°C to 105°C Block Diagram Figure3. Block Diagram 联系人：殷先生 TEL：13380368939 QQ：719307610 SY5800A AN_SY5800 Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 5 Electrical Characteristics (VIN = 12V (Note 3), TA = 25°C unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Power Supply Section Input voltage range VVIN 8 15.4 V VIN turn-on threshold VVIN,ON 17.6 V VIN turn-off threshold VVIN,OFF 6.0 7.9 V VIN OVP voltage VVIN,OVP VVIN_ON+0.85 V Start up Current IST VVINVVIN,OVP 1.6 2 2.5 mA Error Amplifier Section Internal reference voltage VREF 0.294 0.3 0.306 V Current Sense Section Current limit reference voltage VISEN,MAX 0.5 V ZCS pin Section ZCS pin OVP voltage threshold VZCS,OVP 1.42 V Gate Driver Section Gate driver voltage VGate VVIN V Maximum source current ISOURCE 1 A Minimum sink current ISINK 2 A Max ON Time TON,MAX VCOMP=1.5V 24 µs Min ON Time TON,MIN 400 ns Max OFF Time TOFF,MAX 39 µs Min OFF Time TOFF,MIN 2 µs Maximum switching frequency fMAX 120 kHz Enable function Section Enable ON VEN,ON 1.5 V Enable OFF VEN,OFF 0.2 V Thermal Section Thermal Shutdown Temperature TSD 150 °C Note 1: Stresses beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 2: ſJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Test condition: Device mounted on 2” x 2” FR-4 substrate PCB, 2oz copper, with minimum recommended pad on top layer and thermal vias to bottom layer ground plane. Note 3: Increase VIN pin voltage gradually higher than VVIN,ON voltage then turn down to 12V. 联系人：殷先生 TEL：13380368939 QQ：719307610 SY5800A AN_SY5800 Rev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 6 Operation SY5800A is a constant current Flyback controller with primary side control and PFC function that targets at LED lighting applications. The Device provides primary side control to eliminate the opto-couplers or the secondary feedback circuits, which would cut down the cost of the system. High power factor is achieved by constant on operation mode, with which the control scheme and the circuit structure are both simple. In order to reduce the switching losses and improve EMI performance, Quasi-Resonant switching mode is applied, which means to turn on the power MOSFET at voltage valley; the start up current of SY5800A is rather small (15uA typically) to reduce the standby power loss further; the maximum switching frequency is clamped to 120kHz to reduce switching losses and improve EMI performance when the converter is operated at light load condition. SY5800A provides reliable protections such as Short Circuit Protection (SCP), Open LED Protection (OLP), Over Temperature Protection (OTP), etc. SY5800A is available with SO8 and MSOP10 package. Applications Information Start up After AC supply or DC BUS is powered on, the capacitor CVIN across VIN and GND pin is charged up by BUS voltage through a start up resistor RST. Once VVIN rises up to VVIN-ON, the internal blocks start to work. VVIN will be pulled down by internal consumption of IC until the auxiliary winding of Flyback transformer could supply enough energy to maintain VVIN above VVIN-OFF. The whole start up procedure is divided into two sections shown in Fig.4. tSTC is the CVIN charged up section, and tSTO is the output voltage built-up section. The start up time tST composes of tSTC and tSTO, and usually tSTO is much smaller than tSTC. VIN SY5800 VBUS RST CVIN Fig.4 Start up The start up resistor RST and CVIN are designed by rules below: (a) Preset start-up resistor RST, make sure that the current through RST is larger than IST and smaller than IVIN_OVP BUS BUS ST VIN_OVP ST V V RV N1- V N × × × (12), And, ZCS_OVP S OVP AUX ZCSD ZCSU ZCS_OVP S OVP AUX V N V N R RV N1- V N × ≥ × × (13) Where VOVP is the output over voltage protection specification; VOUT is the rated output voltage; RZCSU is the upper resistor of the divider; NS and NAUX are the turns of secondary winding and auxiliary winding separately. Power Device Design MOSFET and Diode When the operation condition is with maximum input voltage and full load, the voltage stress of MOSFET and secondary power diode is maximized; MOS_DS_MAX AC_MAX PS OUT D_F SV = 2V +N (V +V )+∆V× (14) AC_MAX D_R_MAX OUT PS 2V V = +V N (15) Where VAC,MAX is maximum input AC RMS voltage; NPS is the turns ratio of the Flyback transformer; VOUT is the rated output voltage; VD,F is the forward voltage of secondary power diode; ∆VS is the overshoot voltage clamped by RCD snubber during OFF time. When the operation condition is with minimum input voltage and full load, the current stress of MOSFET and power diode is maximized. MOS_PK_MAX P_PK_MAXI =I (16) MOS_RMS_MAX P_RMS_MAXI =I (17) D_PK_MAX PS P_PK_MAXI =N I× (18) D_AVG OUTI =I (19) Where IP-PK-MAX and IP-RMS-MAX are maximum primary peak current and RMS current, which will be introduced later. Transformer (NPS and LM) NPS is limited by the electrical stress of the power MOSFET: MOS_(BR)DS AC_MAX S PS OUT D_F V 90%- 2V -∆V N V +V × ≤ (20) Where VMOS,(BR)DS is the breakdown voltage of the power MOSFET. In Quasi-Resonant mode, each switching period cycle tS consists of three parts: current rising time t1, current falling time t2 and quasi-resonant time t3 shown in Fig.9. VDS IPRI VG ISEC IOUT t2 tS IPP ISP t1 t3 Fig.9 switching waveforms The system operates in the constant on time mode to achieve high power factor. The ON time increases with the input AC RMS voltage decreasing and the load 联系人：殷先生 TEL：13380368939 QQ：719307610 SY5800A AN_SY5800ARev1.0A Silergy Corp. Confidential- Prepared for Customer Use Only 10 increasing. When the operation condition is with minimum input AC RMS voltage and full load, the ON time is maximized. On the other hand, when the input voltage is at the peak value, the OFF time is maximized. Thus, the minimum switching frequency fS-MIN happens at the peak value of input voltage with minimum input AC RMS voltage and maximum load condition; Meanwhile, the maximum peak current through MOSFET and the transformer happens. Once the minimum frequency fS-MIN is set, the inductance of the transformer could be induced. The design flow is shown as below: (a)Select NPS MOS_(BR)DS AC_MAX S PS OUT D_F V 90%- 2V -∆V N V +V × ≤ (21) (b) Preset minimum frequency fS-MIN (c) Compute relative tS, t1 (t3 is omitted to simplify the design here) S S_MIN 1 t = f (22) S PS OUT D_F 1 AC_MIN PS OUT D_F t N (V +V ) t = 2V +N (V +V ) × × × (23)