FSDM0465RBWDTU

www.fairchildsemi.com FSDM0465RB Features Green Mode Fairchild Power Switch (FPSTM) • Internal Avalanche Rugged SenseFET • Advanced Burst-Mode Operation Consumes Under One W at 240VAC & 0.5W Load • Precision Fixed Operating Frequency (66kHz) • Internal Start-up Circuit • Improved Pulse by Pulse Current Limiting • Over Voltage Protection (OVP) : Auto-Restart • Over Load Protection (OLP): Auto-Restart • Internal Thermal Shutdown (TSD) : Auto-Restart • Under Voltage Lock Out (UVLO) with Hysteresis • Low Operating Current (2.5mA) • Built-in Soft Start OUTPUT POWER TABLE (4) 230VAC ±15%(3) PRODUCT FSDM0465RB FSDM0565RB FSDM07652RB FSDM12652RB Adapter(1) 48W 60W 70W 90W Open Frame(2) 56W 70W 80W 110W 85-265VAC Adapter(1) 40W 50W 60W 80W Open Frame(2) 48W 60W 70W 90W Table 1. Maximum Output Power Notes: 1. Typical continuous power in a non-ventilated enclosed adapter measured at 50°C ambient. 2. Maximum practical continuous power in an open frame design at 50°C ambient. 3. 230 VAC or 100/115 VAC with doubler. 4. The junction temperature can limit the maximum output power. Application • SMPS for LCD monitor and STB • Adapter Related Application Notes • AN4137 - Design Guidelines for Off-line Flyback Converters Using Fairchild Power Switch (FPS) • AN4140 - Transformer Design Consideration for Off-line Flyback Converters Using Fairchild Power Switch • AN4141 - Troubleshooting and Design Tips for Fairchild Power Switch Flyback Applications • AN4148 - Audible Noise Reduction Techniques for FPS Applications Typical Circuit Description The FSDM0465RB is an integrated Pulse Width Modulator (PWM) and SenseFET specifically designed for high performance offline Switch Mode Power Supplies (SMPS) with minimal external components. This device is an integrated high voltage power switching regulator which combines a rugged avalanche, SenseFET with a current mode PWM control block. The PWM controller includes integrated fixed frequency oscillator, under voltage lockout, leading edge blanking (LEB), optimized gate driver, internal soft start, temperature compensated precise current sources for a loop compensation and self protection circuitry. Compared with a discrete MOSFET and PWM controller solution, the PWM/ FSDMRB can reduce total cost, component count, size and weigh, while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform well suited for cost-effective designs of flyback converters. AC IN DC OUT Vstr PWM Vfb Drain Vcc Source Figure 1. Typical Flyback Application FPSTM is a trademark of Fairchild Semiconductor Corporation Rev.1.0.0 ©2005 Fairchild Semiconductor Corporation FSDM0465RB Internal Block Diagram Vcc 3 N.C 5 0.5/0.7V + Vstr 6 Drain 1 ICH Vref 8V/12V Vcc good Internal Bias Vcc Idelay Vref OSC IFB 2.5R PWM S Q VFB 4 R Q Soft start R Gate driver LEB VSD Vcc S Q 2 GND Vovp TSD Vcc good Vcc Good R Q VCL Figure 2. Functional Block Diagram of FSDM0465RB 2 FSDM0465RB Pin Description Pin Number 1 2 3 Pin Name Drain GND Vcc Pin Function Description This pin is the high voltage power SenseFET drain. It is designed to drive the transformer directly. This pin is the control ground and the SenseFET source. This pin is the positive supply voltage input. During start up, the power is supplied by an internal high voltage current source that is connected to the Vstr pin. When Vcc reaches 12V, the internal high voltage current source is disabled and the power is supplied from the auxiliary transformer winding. This pin is internally connected to the inverting input of the PWM comparator. The collector of an opto-coupler is typically tied to this pin. For stable operation, a capacitor should be placed between this pin and GND. If the voltage of this pin reaches 6.0V, the over load protection is activated resulting in shutdown of the FPSTM. This pin is connected directly to the high voltage DC link. At startup, the internal high voltage current source supplies internal bias and charges the external capacitor that is connected to the Vcc pin. Once Vcc reaches 12V, the internal current source is disabled. 4 Vfb 5 6 N.C Vstr Pin Assignments TO-220F-6L 6.Vstr 5.N.C. 4.Vfb 3.Vcc 2.GND 1.Drain Figure 3. Pin Configuration (Top View) 3 FSDM0465RB Absolute Maximum Ratings (Ta=25°C, unless otherwise specified) Parameter Drain-source Voltage Vstr Max Voltage Pulsed Drain Current (Tc=25°C) (1) Symbol VDSS VSTR IDM ID ID * Value 650 650 9.6 2.2 1.4 4 20 -0.3 to VCC 33 Internally limited -25 to +85 -55 to +150 2.0 (GND-Vstr/Vfb=1.5kV) 300 (GND-Vstr/Vfb=225V) Unit V V A A (rms) A (rms) A (rms) mJ V V W °C °C °C kV V Continuous Drain Current (Tc=25°C) (2) Continuous Drain Current (Tc=100°C) (2) Continuous Drain Current (TDL=25°C) Single Pulsed Avalanche Supply Voltage Input Voltage Range Total Power Dissipation (Tc=25°C) (2) Operating Junction Temperature Operating Ambient Temperature Storage Temperature Range ESD Capability, HBM Model (All pins except Vstr and Vfb) ESD Capability, Machine Model (All pins except Vstr and Vfb) Energy (4) * (3) EAS VCC VFB PD Tj TA TSTG - Notes: 1. Repetitive Rating: Pulse width limited by maximum junction temperature 2. Tc: Case Back Surface Temperature (With infinite heat sink) 3. TDL: Drain Lead Temperature (With infinite heat sink) 4. L=14mH, starting Tj=25°C2. L=14mH, starting Tj=25°C Thermal Impedance Parameter Junction-to-Ambient Thermal Junction-to-Case Thermal Notes: 1. Infinite cooling condition - refer to the SEMI G30-88. Symbol Value 3.78 Unit °C/W °C/W θJA θJC(1) 4 FSDM0465RB Electrical Characteristics (Ta = 25°C unless otherwise specified) Parameter SenseFET SECTION Drain Source Breakdown Voltage BVDSS VGS = 0V, ID = 250µA VDS = 650V, VGS = 0V Zero Gate Voltage Drain Current Static Drain Source On Resistance (1) Output Capacitance Turn On Delay Time Rise Time Turn Off Delay Time Fall Time CONTROL SECTION Initial Frequency Voltage Stability Temperature Stability (2) Maximum Duty Cycle Minimum Duty Cycle Start Threshold Voltage Stop Threshold Voltage Feedback Source Current Soft-start Time Leading Edge Blanking Time BURST MODE SECTION Burst Mode Voltages VBURH VBURL Vcc=14V Vcc=14V 0.7 0.5 V V FOSC FSTABLE ∆FOSC DMAX DMIN VSTART VSTOP IFB TS TLEB VFB=GND VFB=GND VFB=GND Vfb=3 VFB = 3V 13V ≤ Vcc ≤ 18V -25°C ≤ Ta ≤ 85°C 60 0 0 77 11 7 0.7 66 1 ±5 82 12 8 0.9 10 250 72 3 ±10 87 0 13 9 1.1 15 kHz % % % % V V mA ms ns IDSS VDS= 520V VGS = 0V, TC = 125°C VGS = 10V, ID = 2.5A VGS = 0V, VDS = 25V, f = 1MHz VDD= 325V, ID= 3.2A 650 2.2 60 23 20 65 27 250 250 2.6 ns V µA µA Ω Symbol Condition Min. Typ. Max. Unit RDS(ON) COSS TD(ON) TR TD(OFF) TF pF 5 FSDM0465RB Electrical Characteristics (Continued) (Ta = 25°C unless otherwise specified) Parameter PROTECTION SECTION Peak Current Limit (3) Over Voltage Protection Thermal Shutdown Temperature (2) Shutdown Feedback Voltage Shutdown Delay Current TOTAL DEVICE SECTION Startup Current (4) Istart IOP Operating Supply Current (4) IOP(MIN) IOP(MAX) VFB=GND, VCC=11V VFB=GND, VCC=14V VFB=GND, VCC=10V VFB=GND, VCC=18V 2.5 5 mA 1 1.3 mA IOVER VOVP TSD VSD IDELAY VFB=5V, VCC=14V 1.6 18 130 5.5 2.8 1.8 19 145 6.0 3.5 2.0 20 160 6.5 4.2 A V °C V µA Symbol Condition Min. Typ. Max. Unit VFB ≥ 5.5V VFB=5V Notes: 1. Pulse test: Pulse width ≤ 300µS, duty ≤ 2% 2. These parameters, although guaranteed at the design, are not tested in mass production. 3. These parameters indicate the inductor current. 4. This parameter is the current flowing into the control IC. 6 FSDM0465RB Typical Performance Characteristics (These Characteristic Graphs are Normalized at Ta= 25°C) 1.2 1.0 1. 2 1. 0 Start Threshold Voltage (Vstart) 0. 8 0. 6 0. 4 0. 2 0. 0 -25 0 25 50 75 100 125 150 Operating Current (Iop) 0.8 0.6 0.4 0.2 0.0 Ju nc tion Te mpe ratu re (℃ ) -25 0 25 50 75 100 125 150 Junction Temperature(℃) Operating Current vs. Temp 1.2 1.0 Stop Threshold Voltage (Vstop) Operating Frequency (Fosc) Start Threshold Voltage vs. Temp 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Ju nc tion Te mpe ratu re (℃ ) -25 0 25 50 75 100 125 150 Ju nc tion Te mpe ratu re (℃ ) Stop Threshold Voltage vs. Temp Operating Frequency vs. Temp 1.2 1.0 Maximum Duty Cycle (Dmax) 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Ju nc tion Te mpe ratu re (℃ ) 1. 2 1. 0 FB Source Current (Ifb) 0. 8 0. 6 0. 4 0. 2 0. 0 -25 0 25 50 75 100 125 150 Ju nc tion Tempe rature (℃ ) Maximum Duty vs. Temp Feedback Source Current vs. Temp 7 FSDM0465RB Typical Performance Characteristics (Continued) (These Characteristic Graphs are Normalized at Ta= 25°C) 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Ju nc tion Te mpe ratu re (℃ ) 1.2 1.0 Shutdown Delay Current (Idelay) 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Ju n c tion T e mpe ra tu re (℃ ) Shutdown FB Voltage (Vsd) Shutdown Feedback Voltage vs. Temp Shutdown Delay Current vs. Temp 1.2 Over Voltage Protection (Vovp) 1.0 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Junction Temperature(℃) FB Burst Mode Enable Voltage (Vfbe) 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Junction Temperature(℃) Over Voltage Protection vs. Temp Burst Mode Enable Voltage vs. Temp 1.2 Peak Current Limit(Self protection) (Iover) 1.0 0.8 0.6 0.4 0.2 0.0 -50 -25 0 25 50 75 100 125 Ju nc tion Te mpe ratu re (℃ ) FB Burst Mode Disable Voltage (Vfbd) 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -25 0 25 50 75 100 125 150 Junction Temperature(℃) Burst Mode Disable Voltage vs. Temp Current Limit vs. Temp 8 FSDM0465RB Typical Performance Characteristics (Continued) (These Characteristic Graphs are Normalized at Ta= 25°C) 1.2 1.0 Soft Start Time (Normalized to 25℃) 0.8 0.6 0.4 0.2 0.0 -50 -25 0 25 50 75 100 125 Junction Temperature(℃ ) Soft Start Time vs. Temp 9 FSDM0465RB Functional Description 1. Startup: In previous generations of Fairchild Power Switches (FPSTM) the Vcc pin had an external start-up resistor to the DC input voltage line. In this generation the startup resistor is replaced by an internal high voltage current source. At startup, an internal high voltage current source supplies the internal bias and charges the external capacitor (Ca) that is connected to the Vcc pin as illustrated in Figure 4. When Vcc reaches 12V, the FSDM0465RB begins switching and the internal high voltage current source is disabled. Then, the FSDM0465RB continues its normal switching operation and the power is supplied from the auxiliary transformer winding unless Vcc goes below the stop voltage of 8V. 2.1 Pulse-by-Pulse Current Limit: Because current mode control is employed, the peak current through the SenseFET is limited by the inverting input of the PWM comparator (Vfb*) as shown in Figure 5. Assuming that the 0.9mA current source flows only through the internal resistor (2.5R +R= 2.8 kΩ), the cathode voltage of diode D2 is about 2.5V. Since D1 is blocked when the feedback voltage (Vfb) exceeds 2.5V, the maximum voltage of the cathode of D2 is clamped at this voltage, thus clamping Vfb*. Therefore, the peak value of the current through the SenseFET is limited. 2.2 Leading Edge Blanking (LEB): At the instant the internal SenseFET is turned on, there usually exists a high current spike through the SenseFET, caused by primary-side capacitance and secondary-side rectifier reverse recovery. Excessive voltage across the Rsense resistor would lead to incorrect feedback operation in the current mode PWM control. To counter this effect, the FSDM0465RB employs an LEB circuit. This circuit inhibits the PWM comparator for a short time (TLEB) after the, SenseFET is turned on. VDC Ca Vcc Idelay Vref IFB OSC Vcc 3 6 Vstr Vo Vfb H11A817A CB 4 D1 D2 2.5R + Vfb* SenseFET ICH Vref 8V/12V Vcc good Vcc Good Internal Bias VSD KA431 R Gate Gate driver Driver - OLP Rsense Figure 5. Pulse Width Modulation (PWM) Circuit Figure 4. Internal Startup Circuit 2. Feedback Control: FSDM0465RB employs current mode control, as shown in Figure 5. An opto-coupler (such as the H11A817A) and shunt regulator (such as the KA431) are typically used to implement the feedback network. Comparing the feedback voltage with the voltage across the Rsense resistor plus an offset voltage makes it possible to control the switching duty cycle. When the reference pin voltage of the KA431 exceeds the internal reference voltage of 2.5V, the H11A817A LED current increases, thus decreasing the feedback voltage and reducing the duty cycle. This event typically happens when the input voltage is increased or the output load is decreased. 3. Protection Circuit: The FSDM0465RB has several self protective functions such as over load protection (OLP), over voltage protection (OVP), and thermal shutdown (TSD). Because these protection circuits are fully integrated into the IC without external components, the reliability can be improved without increasing cost. Once the fault condition occurs, switching is terminated and the SenseFET remains off. This causes Vcc to fall. When Vcc reaches the UVLO stop voltage, 8V, the protection is reset and the internal high voltage current source charges the Vcc capacitor via the Vstr pin. When Vcc reaches the UVLO start voltage,12V, the FSDM0465RB resumes its normal operation. In this manner, the auto-restart can alternately enable and disable the switching of the power Sense FET until the fault condition is eliminated (see Figure 6). 10 FSDM0465RB Vds Power On on Fault Occurs occurs Fault Removed removed VFB Over Load protection load Protection 6.0V 2.5V Vcc T 12= C fb* (6.0-2.5) / Idelay 12V 8V T1 T2 t Figure 7. Over Load Protection t Normal Operation operation Fault Situation situation Normal Operation operation Figure 6. Auto Restart Operation 3.1 Over Load Protection (OLP): Overload is defined as the load current exceeding a pre-set level due to an unexpected event. In this situation, the protection circuit should be activated to protect the SMPS. However, even when the SMPS is operation normally, the over load protection circuit can be activated during the load transition. To avoid this undesired operation, the over load protection circuit is designed to be activated after a specified time to determine whether it is a transient situation or an overload situation. Because of the pulse-by-pulse current limit capability, the maximum peak current through the SenseFET is limited, and therefore the maximum input power is restricted with a given input voltage. If the output consumes beyond this maximum power, the output voltage (Vo) decreases below the set voltage. This reduces the current through the opto-coupler LED, which also reduces the opto-coupler transistor current, thus increasing the feedback voltage (Vfb). If Vfb exceeds 2.5V, D1 is blocked and the 3.5uA current source starts to charge CB slowly up to Vcc. In this condition, Vfb continues increasing until it reaches 6V, when the switching operation is terminated as shown in Figure 7. The delay time for shutdown is the time required to charge CB from 2.5V to 6.0V with 3.5uA. In general, a 10 ~ 50 ms delay time is typical for most applications. 3.2 Over Voltage Protection (OVP): If the secondary side feedback circuit malfunction or a solder defect caused an open in the feedback path, the current through the optocoupler transistor becomes almost zero. Then, Vfb climbs up in a similar manner to the over load situation, forcing the preset maximum current to be supplied to the SMPS until the over load protection is activated. Because more energy than required is provided to the output, the output voltage may exceed the rated voltage before the over load protection is activated, resulting in the breakdown of the devices in the secondary side. To prevent this situation, an OVP circuit is employed. In general, Vcc is proportional to the output voltage and the FSDM0465RB uses Vcc instead of directly monitoring the output voltage. If VCC exceeds 19V, an OVP circuit is activated resulting in the termination of the switching operation. To avoid undesired activation of OVP during normal operation, Vcc should be designed to be below 19V. 3.3 Thermal Shutdown (TSD): The SenseFET and the control IC are built in one package. This makes it easy for the control IC to detect the heat generation from the Sense FET. When the temperature exceeds approximately 150°C, the thermal shutdown is activated. 4. Soft Start: The FSDM0465RB’s internal soft-start circuit slowly increases the PWM comparator’s inverting input voltage along with the SenseFET current after it starts up. The typical soft-start time is 10msec, The pulse width to the power switching device is progressively increased to establish the correct working conditions for transformers, inductors, and capacitors. The voltage on the output capacitors is progressively increased with the intention of smoothly establishing the required output voltage. It also helps to prevent transformer saturation and reduce the stress on the secondary diode during startup. 11 FSDM0465RB 5. Burst Operation: To minimize power dissipation in standby mode, the FSDM0465RB enters burst mode operation. As the load decreases, the feedback voltage decreases. As shown in Figure 8, the device automatically enters burst mode when the feedback voltage drops below VBURL(500mV). At this point switching stops and the output voltages start to drop at a rate dependent on the standby current load. This causes the feedback voltage to rise. Once it passes VBURH(700mV), switching resumes. The feedback voltage then falls and the process repeats. Burst mode operation alternately enables and disables switching of the power SenseFET thereby reducing switching loss in Standby mode. Vo Voset VFB 0.7V 0.5V Ids Vds time Switching Switching Switching Switching disabled disabled T1 Disabled T2 T3 Disabled T4 Figure 8. Waveforms of Burst Operation 12 FSDM0465RB Typical application circuit Application LCD Monitor Output Power 34W Input Voltage Universal Input (85-265Vac) Output Voltage (Max Current) 5V (2.0A) 12V (2.0A) Features • • • • • • High efficiency (>81% at 85Vac input) Low zero load power consumption (