Fairchild Reference Design

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1 Fairchild Reference Design This reference design supports inclusion of the FSL306LRN. It should be used in conjunction with the FSL306LRN datasheet as well as Fairchild s application notes and technical support team. Please visit Fairchild s website at Application Buck-Boost Converter Fairchild Device Input Voltage Range Maximum Output Power Output Full-Load Condition FSL306LRN V AC 0.5 W -5 V (0.1 A) General Description The FSL306LRN integrated Pulse Width Modulator (PWM) with SenseFET is specifically designed for high-performance offline buck, buck-boost, and non-isolation flyback Switched Mode Power Supplies (SMPS) with minimal external components. This device integrates a high-voltage power regulator that enables operation without auxiliary bias winding. An internal transconductance amplifier reduces external components for the feedback compensation circuit. The integrated PWM controller includes: 10 V regulator for no external bias circuit, Under-Voltage Lockout (UVLO), Leading-Edge Blanking (LEB), an optimized gate turnon / turn-off driver, EMI attenuator, Thermal Shutdown (TSD), temperature-compensated precision current sources for loop compensation, and fault-protection circuitry. Protections include: Overload Protection (OLP), Over-Voltage Protection (OVP), Feedback Open-Loop Protection (FB_OLP), and Abnormal Over-Current Protection (AOCP). The FSL306LRN offers good soft-start performance during startup. The internal high-voltage startup switch and the Burst-Mode operation with very low operating current reduce power loss in Standby Mode. As the result, it is possible to reach power loss of 120 mw without external bias and 25 mw with external bias when the input voltage is 230 V AC. Key Features Built-in Avalanche-Rugged SenseFET: 650 V Fixed Operating Frequency: 50 khz No-Load Power Consumption: <25 mw at 230 V AC with External Bias; <120 mw at 230 V AC without External Bias No Need for Auxiliary Bias Winding Frequency Modulation for Attenuating EMI Pulse-by-Pulse Current Limiting Built-in Soft-Start and Startup Circuit Adjustable Peak Current Limit Built-in Transconductance (Error) Amplifier Protections: Overload Protection (OLP), Over-Voltage Protection (OVP), Feedback Open Loop Protection (FB_OLP), AOCP (Abnormal Over-Current Protection), Thermal Shutdown (TSD) Fixed 650 ms Restart Time for Safe Auto-Restart Mode of All Protections 2013 Fairchild Semiconductor Corporation 1 RD-L044_FSL306LRN Rev

2 VCC Drain 2 6,7 Internal Bias VCC Good 10V HVREG VSTART / VSTOP VBIAS Transconductance Amplifier VFB 4 VREF VBIAS VBURH/VBURL Green- Mode Controller OSC IPK S Q 3R PWM R Q Gate Driver R Soft Start LEB ILIMIT 3 VSENSE 650ms Protection Timing Control VCOMP 5 VOLP 40ms Delay VSENSE LEB RSENSE Vcc 1 GND VOVP VFB VAOCP TSD VFB_OLP Figure 1. Internal Block Diagram Schematic D1 and D2 are selected for AC half-bridge rectification; especially D2 is helpful for better average performance of conducted EMI. R1 not only restricts inrush current, but also improves EMI performance. For improved conducted EMI performance, a pi-type filter is designed with L2, R5, C1, and C2. The rectified input voltage is applied to the drain pin; L1, D4, C3, and the SenseFET compose buck-boost converter for negative 5V output voltage. The internal high-voltage regulator regulates the bias voltage (V CC ) with only one small capacitor (without other additional external components). Adjusted current limit through the I LIMIT pin optimizes the inductor (L1) size; R6 reduces current limit; and C5 improves noise immunity on the I LIMIT pin. AC D1 S1M D2 S1M R1 5Ω 1W R3 3MΩ 1206 C1 1uF 400V L2 1mH R5 3.3kΩ C6 220nF R8 75kΩ C2 1uF 400V C7 10nF U1 FSL306LR 5.Vcomp VCOMP 4.VFB 7.D Drain 8.D Drain 3.ILIMIT 2.VC VCC C 1.GND C5 R6 1nF 56kΩ C4 100nF R9 1kΩ R10 1kΩ C8 2.2uF FB L1 1mH D4 RS1J R7 5.1kΩ D3 RS1J C3 68uF/25V -5V output GND FB Figure 2. Schematic 2013 Fairchild Semiconductor Corporation 2 RD-L044_FSL306LRN Rev

3 Bill of Materials Component Qty. Part No. Manufacturer Reference Wire Wound Resistor 1 W 5R ±5% 1 R1 Chip Resistor 1 kω ±5% 2 R9, R10 Chip Resistor 3.3 kω ±1% 1 R5 Chip Resistor 5.1 kω ±1% 1 R7 Chip Resistor 56 kω ±1% 1 R6 Chip Resistor 75 kω ±5% 1 R8 Chip Resistor 3 MΩ ±5% 1 R3 MLCC X7R ±10% 102P (1 nf) 50 V 1 C5 MLCC X7R ±10% 103P (10 nf) 50 V 1 C7 MLCC X7R ±10% 224P (100 nf) 50 V 1 C4 MLCC X7R ±10% 224P (220 nf) 50 V 1 C6 Electrolytic Capacitor 1 µf 400 V 105 C 2 C1, C2 MLCC X7R ±10% 225P (2.2 µf) 50 V 1 C8 Electrolytic Capacitor 68 µf 400 V 105 C 1 C3 Fixed Inductor 1 mh ±10% 1 EC36-102K SYNTON L2 Inductor 1 mh 1 L1 General Diode 1 A / 1000 V SMA 2 S1M Fairchild Semiconductor D1, D2 Fast Diode 1 A / 600 V SMA 2 RS1J Fairchild Semiconductor D3, D4 IC SMPS Power Switch 1 FSL306LR Fairchild Semiconductor U Fairchild Semiconductor Corporation 3 RD-L044_FSL306LRN Rev

4 Performance of Design Example Output Ripple and Noise Figure 3. Recommended Test Setup Figure 4. 5 V Output Ripple & Noise Output Line and Load Regulation Figure 5. 5 V Output Line & Load Regulation 2013 Fairchild Semiconductor Corporation 4 RD-L044_FSL306LRN Rev

5 Conducted Electromagnetic Interference (EMI) Measurement R B W 9 k H z M T 2 0 m s A t t 1 0 d B P R E A M P O F F dbµv M H z 1 0 M H z 90 1 PK 80 2 AV 70 TDF E N Q 60 E N A 50 PRN 40 6DB k H z 3 0 M H z C o m m e n t : N D a t e : 2 7. J U N : 0 5 : 0 5 Figure 6. Line at 110 V AC R B W 9 k H z M T 2 0 m s A t t 1 0 d B P R E A M P O F F dbµv M H z 1 0 M H z 90 1 PK 80 2 AV 70 TDF E N Q 60 E N A 50 PRN 40 6DB k H z 3 0 M H z C o m m e n t : N D a t e : 2 7. J U N : 0 8 : 0 3 Figure 7. Line at 230V AC 2013 Fairchild Semiconductor Corporation 5 RD-L044_FSL306LRN Rev

6 Full Load Efficiency Figure 9. Efficiency Test Result Standby Power Consumption Figure 10. Standby Power Consumption 2013 Fairchild Semiconductor Corporation 6 RD-L044_FSL306LRN Rev

7 Related Resources FSL306LRN Datasheet of Green Mode Fairchild Buck Switch AN-5844 Green Mode Fairchild Buck Switch Reference Design Disclaimer Fairchild Semiconductor Corporation ( Fairchild ) provides these reference design services as a benefit to our customers. Fairchild has made a good faith attempt to build for the specifications provided or needed by the customer. Fairchild provides this product as is and without recourse and MAKES NO WARRANTY, EXPRESSED, IMPLIED OR OTHERWISE, INCLUDING ANY WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Customer agrees to do its own testing of any Fairchild reference designs in order to ensure design meets the customer needs. Neither Fairchild nor Customer shall be liable for incidental or consequential damages, including but not limited to, the cost of labor, requalifications, rework charges, delay, lost profits, or loss of goodwill arising out of the sale, installation or use of any Fairchild product. Subject to the limitations herein, Fairchild will defend any suit or proceeding brought against Customer if it is based on a claim that any product furnished hereunder constitutes an infringement of any intellectual property rights. Fairchild must be notified promptly in writing and given full and complete authority, information and assistance (at Fairchild s expense) for defense of the suit. Fairchild will pay damages and costs therein awarded against Customer but shall not be responsible for any compromise made without its consent. In no event shall Fairchild s liability for all damages and costs (including the costs of the defense by Fairchild) exceed the contractual value of the products or services that are the subject of the lawsuit. In providing such defense, or in the event that such product is held to constitute infringement and the use of the product is enjoined, Fairchild, in its discretion, shall procure the right to continue using such product, or modify it so that it becomes noninfringing, or remove it and grant Customer a credit for the depreciated value thereof. Fairchild s indemnity does not extend to claims of infringement arising from Fairchild s compliance with Customer s design, specifications and/or instructions, or the use of any product in combination with other products or in connection with a manufacturing or other process. The foregoing remedy is exclusive and constitutes Fairchild s sole obligation for any claim of intellectual property infringement and Fairchild makes no warranty that products sold hereunder will not infringe any intellectual property rights. All solutions, designs, schematics, drawings, boards or other information provided by Fairchild to Customer are confidential and provided for Customer s own use. Customer may not share any Fairchild materials with other semiconductor suppliers Fairchild Semiconductor Corporation 7 RD-L044_FSL306LRN Rev