FSCM0565RD

www.fairchildsemi.com FSCM0565R Features Green Mode Fairchild Power Switch (FPSTM) • Internal Avalanche Rugged Sense FET • Low startup current (max 40uA) • Low power consumption under 1 W at 240VAC & 0.4W load • Precise Fixed Operating Frequency (66kHz) • Frequency Modulation for low EMI • Pulse by Pulse Current Limiting (Adjustable) • Over Voltage Protection (OVP) • Over Load Protection (OLP) • Thermal Shutdown Function (TSD) • Auto-Restart Mode • Under Voltage Lock Out (UVLO) with hysteresis • Built-in Soft Start (15ms) Table 1. Maximum Output Power OUTPUT POWER TABLE 230VAC ±15%(3) PRODUCT FSCM0565RD FSCM0765RD FSCM0565RC FSCM0765RC Adapter(1) 50W 65W 70W 85W Open Frame(2) 65W 70W 85W 95W 85-265VAC Adapter(1) 40W 50W 60W 70W Open Frame(2) 50W 60W 70W 85W Application • SMPS for VCR, SVR, STB, DVD & DVCD • Adaptor • SMPS for LCD Monitor 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. Description The FSCM0565R is an integrated Pulse Width Modulator (PWM) and Sense FET 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 combine an avalanche rugged Sense FET 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 discrete MOSFET and PWM controller solution, it can reduce total cost, component count, size and weight simultaneously increasing efficiency, productivity, and system reliability. This device is a basic platform well suited for cost effective designs of flyback converters. Typical Circuit DC OUT AC IN Drain PWM Ilimit Vfb Vcc GND Figure 1. Typical Flyback Application Rev.1.0.0 ©2005 Fairchild Semiconductor Corporation FSCM0565R Internal Block Diagram Vcc 3 Vcc good Vref 0.3/0.5V + Drain 1 Internal Bias 8V/12V Freq. Modulation Vcc Idelay Vcc OSC IFB PWM 2.5R S Q FB 4 Ilimit 5 R Q R Soft start 0.3K Gate driver LEB VSD Vcc S Q 2 GND Vovp TSD Vcc UV reset Vcc good R Q Figure 2. Functional Block Diagram of FSCM0565R 2 FSCM0565R Pin Definitions 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. Initially, During start up, the power is supplied through the startup resistor from DC link. When Vcc reaches 12V, the power is supplied from auxiliary transformer winding. This pin is internally connected to the inverting input of the PWM comparator. The collector of an optocoupler 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 FPS. This pin is for the pulse by pulse current limit level programming. By using a resistor to GND on this pin, the current limit level can be changed. If this pin is left floating, the typical current limit will be 2.5A. 4 Feedback (FB) 5 I_limit Pin Configuration FSCM0565RD D2-PAK-5L FSCM0565RC TO-220-5L FSCM0565RD FSCM0565RC 5 : I_limit 4 : FB 3 : Vcc 2 : GND 1 : Drain 5. I_limit 4. FB 3. Vcc 2. GND 1. Drain Figure 3. Pin Configuration (Top View) 3 FSCM0565R Absolute Maximum Ratings (Ta=25°C, unless otherwise specified) Parameter Drain-Source (GND) Voltage Gate-Source (GND) Voltage Drain Current Pulsed @ Tc = 25°C @ TC=100°C Continuous Drain Current (D2-PAK) @ Tc = 25°C @ TC=100°C Supply Voltage Analog Input Voltage Range Total Power Dissipation (D2-PAK) Total Power Dissipation (TO-220) Operating Junction Temperature Operating Ambient Temperature Storage Temperature Range ESD Capability, HBM Model (All pins excepts for Vstr and Vfb) ESD Capability, Machine Model (All pins excepts for Vstr and Vfb) ID ID VCC VFB PD Derating PD Derating TJ TA TSTG (2) (1) Symbol VDSS VDGR VGS IDM ID ID Value 650 650 ±30 20 5 3.2 2.9 1.9 20 -0.3 to VCC 75 0.6 120 0.96 Internally limited -25 to +85 -55 to +150 2.0 (Vcc-Vfb=1.0kV) 300 (Vcc-Vfb=100V) Unit V V V ADC ADC ADC ADC ADC V V W W/°C W W/°C °C °C °C kV V Drain-Gate Voltage (RGS=1MΩ) Continuous Drain Current (TO-220) Notes: 1. Tj = 25°C to 150°C 2. Repetitive rating: Pulse width limited by maximum junction temperature 3. L = 30mH, VDD = 50V, RG = 25Ω, starting Tj = 25°C 4. L = 13uH, starting Tj = 25°C 4 FSCM0565R Electrical Characteristics (Ta = 25°C unless otherwise specified) Parameter Sense FET SECTION Drain source breakdown voltage Zero gate voltage drain current Static drain source on resistance Output capacitance Turn on delay time Rise time Turn off delay time Fall time CONTROL SECTION Initial frequency Modulated frequency range Frequency modulation cycle Voltage stability Temperature stability Maximum duty cycle Minimum duty cycle Start threshold voltage Stop threshold voltage Feedback source current Soft-start time BURST MODE SECTION VBH Burst Mode Voltages VBL Vcc=14V 0.24 0.3 0.36 V Vcc=14V 0.4 0.5 0.6 V FOSC ∆Fmod Tmod FSTABLE ∆FOSC DMAX DMIN VSTART VSTOP IFB TSS VFB=GND VFB=GND VFB=GND VCC=14V, VFB=5V 10V≤VCC≤17V −25°C≤Ta≤+85°C 60 0 75 11 7 0.7 10 66 ±3 4 1 ±5 80 12 8 0.9 15 72 3 ±10 85 0 13 9 1.1 20 kHz kHz ms % % % % V V mA ms BVDSS IDSS RDS(ON) COSS TD(ON) TR TD(OFF) TF VGS = 0V, ID = 250µA VDS = Max, Rating VGS = 0V VGS = 10V, ID = 2.3A VGS = 0V, VDS = 25V, f = 1MHz VDD= 325V, ID= 5A (MOSFET switching time is essentially independent of operating temperature) 650 1.76 78 22 52 95 50 500 2.2 ns V µA Ω Symbol Condition Min. Typ. Max. Unit pF 5 FSCM0565R PROTECTION SECTION Peak current limit Over voltage protection Thermal shutdown temperature Shutdown delay current Shutdown feedback voltage TOTAL DEVICE SECTION Startup current Operating supply current Istart IOP(MIN) IOP(MAX) VCC=10V, VFB=0V VCC=20V, VFB=0V 20 2.5 40 5 µA mA ILIM VOVP TSD IDELAY VSD VFB=4V VFB>5.5V VCC=14V, VFB=5V 2.2 18 130 3.5 5.5 2.5 19 145 5.3 6 2.8 20 160 7 6.5 A V °C µA V 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, although guaranteed, are tested in EDS (wafer test) process. 4. These parameters indicate the inductor current. 5. This parameter is the current flowing into the control IC. 6 FSCM0565R Comparison Between FSDM0565RB and FSCM0565R Function Frequency modulation N.A. FSDM0565RB FSCM0565R Available • Modulated frequency range (DFmod) = ±3kHz • Frequency modulation cycle (Tmod) = 4ms • Programmable using external resistor (2.5A max) • N.A. (Requires startup resistor) • Startup current : 40uA (max) Pulse-by-pulse current limit • Internally fixed (2.25A) Internal Startup Circuit • Available 7 FSCM0565R Typical Performance Characteristics (These Characteristic Graphs are Normalized at Ta= 25°C) 1.60 1.40 1.20 1.00 0.80 0.60 -50 -25 0 25 50 75 Junction Temperature(℃) 100 125 1.20 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction T emperature( ℃) Startup Current vs. Temp Start Threshold Voltage (Normalized to 25 ℃) Start up Current (Normalized to 25 ℃) Start Threshold Voltage vs. Temp 1.20 Stop Threshold Voltage (Normalized to 25 ℃) Initial Frequency (Normalized to 25 ℃) 1.20 1.12 1.04 0.96 0.88 0.80 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) -50 -25 0 25 50 75 100 125 Junction Temperature(℃) Stop Threshold Voltage vs. Temp Initial Freqency vs. Temp 1.20 Maximum Duty Cycle (Normalized to 25 ℃) 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) 1.20 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction T emperature(℃) Maximum Duty Cycle vs. Temp FB Source Current (Normalized to 25 ℃) Feedback Source Current vs. Temp 8 FSCM0565R Typical Performance Characteristics (Continued) (These Characteristic Graphs are Normalized at Ta= 25°C) 1.20 Shutdown Delay Curren t (Normalized to 25 ℃) 1.20 1.12 1.04 0.96 0.88 0.80 Shutdown FB Voltag e (Normalized to 25 ℃) 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 Junction T emperature( ℃) 125 -50 -25 0 25 50 75 100 125 Junction T emperature(℃) ShutDown Feedback Voltage vs. Temp 1.20 ShutDown Delay Current vs. Temp 1.20 Burst Mode Disable Voltag e (Normalized to 25 ℃) -50 -25 0 25 50 75 100 125 Burst Mode Enable Voltag e (Normalized to 25 ℃) 1.12 1.04 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) 0.96 0.88 0.80 Junction T emperature( ℃) Bust Mode Enable Volage vs. Temp Burst Mode Disable Voltage vs. Temp 1.20 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) 1.20 Operating Supply Current (Normalized to 25 ℃) 1.12 1.04 0.96 0.88 0.80 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) Maximum Drain Current (Normalized to 25 ℃) Mavimum Drain Current vs. Temp Operating Supply Current vs. Temp 9 FSCM0565R Functional Description 1. Startup : Figure 4 shows the typical startup circuit and transformer auxiliary winding for FSCM0565R application. Before FSCM0565R begins switching, FSCM0565R consumes only startup current (typically 25uA) and the current supplied from the DC link supply ccurrent consumed by FPS (Icc) and charges the external capacitor (Ca) that is connected to the Vcc pin. When Vcc reaches start voltage of 12V (VSTART), FSCM0565R begins switching, and the current consumed by FSCM0565R increases to 3mA. Then, FSCM0565R continues its normal switching operation and the power required for this device is supplied from the transformer auxiliary winding, unless Vcc drops below the stop voltage of 8V (VSTOP). To guarantee the stable operation of the control IC, Vcc has under voltage lockout (UVLO) with 4V hysteresis. Figure 5 shows the relation between the current consumed by FPS (Icc) and the supply voltage (Vcc). The minimum current supplied through the startup resistor is given by min I sup min = ( 2 ⋅ V line – V start ) ⋅ ----------- 1 R str where Vlinemin is the minimum input voltage, Vstart is the start voltage (12V) and Rstr is the startup resistor. The startup resistor should be chosen so that Isupmin is larger than the maximum startup current (40uA). If not, Vcc can not be charged to the start voltage and FPS will fail to start up. C DC 2. Feedback Control : FSCM0565R employs current mode control, as shown in Figure 6. 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 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 pulling down the feedback voltage and reducing the duty cycle. This event typically happens when the input voltage is increased or the output load is decreased. AC line (V linemin - V linemax ) Isup Rstr Da Vcc FSCM0565R Icc Ca Figure 4. Startup circuit 2.1 Pulse-by-pulse current limit: Because current mode control is employed, the peak current through the Sense FET is determined by the inverting input of PWM comparator (Vfb*) as shown in Figure 6. When the current through the opto transistor is zero and the current limit pin (#5) is left floating, the feedback current source (IFB) of 0.9mA flows only through the internal resistor (R+2.5R=2.8k). In this case, the cathode voltage of diode D2 and the peak drain current have maximum values of 2.5V and 2.5A, respectively. The pulse-by-pulse current limit can be adjusted using a resistor to GND on current limit pin (#5). The current limit level using an external resistor (RLIM) is given by R LIM ⋅ 2.5 A I LIM = ----------------------------------2.8k Ω + R LIM Icc Vcc Idelay Vref IFB 0.9mA OSC 3mA Vo Vfb H11A817A CB 4 D1 0.3k D2 2.5R + Vfb* SenseFET Power Down 25uA Vstop=8V Power Up KA431 R Gate driver 5 RLI M - Vcc Vstart=12V Vz VSD OLP Rsense Figure 5. Relation between operating supply current and Vcc voltage Figure 6. Pulse width modulation (PWM) circuit 10 FSCM0565R 2.2 Leading edge blanking (LEB) : At the instant the internal Sense FET is turned on, there usually exists a high current spike through the Sense FET, 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 FSCM0565R employs a leading edge blanking (LEB) circuit. This circuit inhibits the PWM comparator for a short time (TLEB) after the Sense FET is turned on. 3. Protection Circuit : The FSCM0565R 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 Sense FET remains off. This causes Vcc to fall. When Vcc reaches the UVLO stop voltage of 8V, the current consumed by FSCM0565R reduces to the startup current (typically 25uA) and the current supplied from the DC link charges the external capacitor (Ca) that is connected to the Vcc pin. When Vcc reaches the start voltage of 12V, FSCM0565R 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 7). even when the SMPS is in the normal operation, the over load protection circuit can be activated during the load transition. In order 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 Sense FET 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 5.3uA current source (Idelay) 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 8. The delay time for shutdown is the time required to charge CB from 2.5V to 6.0V with 5.3uA (Idelay). In general, a 10 ~ 50 ms delay time is typical for most applications. VFB Over load protection 6.0V 2.5V Vds Power on Fault occurs Fault removed T 12= Cfb*(6.0-2.5)/Idelay T1 T2 t Figure 8. Over load protection Vcc 12V 8V t Normal operation Fault situation Normal operation Figure 7. 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 in order to protect the SMPS. However, 3.2 Over voltage Protection (OVP) : If the secondary side feedback circuit were to malfunction or a solder defect caused an open in the feedback path, the current through the opto-coupler 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. In order to prevent this situation, an over voltage protection (OVP) circuit is employed. In general, Vcc is proportional to the output voltage and the FSCM0565R 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. In order to avoid undesired activation of OVP during normal operation, Vcc should be designed to be below 19V. 11 FSCM0565R 3.3 Thermal Shutdown (TSD) : The Sense FET 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 145°C, the thermal protection is triggered resulting in shutdown of FPS. 4. Frequency Modulation : EMI reduction can be accomplished by modulating the switching frequency of a switched power supply. Frequency modulation can reduce EMI by spreading the energy over a wider frequency range than the band width measured by the EMI test equipment. The amount of EMI reduction is directly related to the depth of the reference frequency. As can be seen in Figure 9, the frequency changes from 63KHz to 69KHz in 4ms. device automatically enters into burst mode when the feedback voltage drops below VBL (300mV). At this point switching stops and the output voltages start to drop at a rate dependent on standby current load. This causes the feedback voltage to rise. Once it passes VBH (500mV) switching resumes. The feedback voltage then falls and the process repeats. Burst mode operation alternately enables and disables switching of the power Sense FET thereby reducing switching loss in standby mode. Vo Voset VFB Drain current 0.5V 0.3V Ids Ts Ts Vds Ts fs 69kHz 66kHz 63kHz time Switching disabled T1 T2 T3 Switching disabled T4 Figure 10. Waveforms of burst operation 4ms t Figure 9. Frequency Modulation 5. Soft Start : The FSCM0565R has an internal soft start circuit that increases PWM comparator inverting input voltage together with the Sense FET current slowly after it starts up. The typical soft start time is 15msec, The pulse width to the power switching device is progressively increased to establish the correct working conditions for transformers, rectifier diodes 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. 6. Burst operation : In order to minimize power dissipation in standby mode, the FSCM0565R enters into burst mode operation at light load condition. As the load decreases, the feedback voltage decreases. As shown in Figure 10, the 12 FSCM0565R Typical application circuit Application LCD Monitor Output power 40W Input voltage Universal input (85-265Vac) Output voltage (Max current) 5V (2.0A) 12V (2.5A) Features • • • • • • High efficiency (>81% at 85Vac input) Low standby mode power consumption (