EPCOS / TDK Component Solutions for SMPS
EPCOS Component Solutions for SMPS has solutions for switch mode power supply electronics ranging from Input EMC line filters to Output filtering capacitors and inductors. The range of products offered by EPCOS for switch mode power supply applications includes common mode filters, ferrite filters, ferrite cores in E, I, U, and ring core forms, X/Y filter capacitors, thermistors, temperature sensors, DC Link capacitors in both film and aluminum, along with Power and housekeeping transformers.
In the design of a Switch Mode Power Supply, quite often the passive components are added as an afterthought to selecting the controller IC and the regulator IC, but the choice of passive components with regard to the ICs will have a huge effect on overall performance. Physical size, generated heat, output power, cost, and efficiency all rely in some degree on the careful selection of the external passive components.
SMPS Circuit Diagram
Input Protection
Input protection includes Varistors and In-Rush Current Limiters. Input Varistors are used to reduce voltage spikes on the incoming power by shorting the spikes to ground. The initial current surge caused by the capacitors in the power supply circuits are smoothed and limited by the in-rush current limiters.
Input Varistors
EPCOS varistors are the optimum Overvoltage Protection components, ideally suited for limiting surge voltage and current as well as for absorbing energy and ESD Protection. The EPCOS product range includes a variety of Radial Leaded discs, Surface Mount types, Thermal Fused types and special types for Automotive and Telecom applications.
• 5.5V to 745VDC Voltage Rating
• 4V to 550VAC Voltage Rating
• 38V to 1.5kV Clamping Voltage
• 7mm to 21.5mm Diameter
• 250A to 12kA Peak Surge Current
• 400mJ to 445J Surge Energy Rating
• 45pF to 7000pF Capacitance
• -40°C to +150°C Operating Temperature Range
• Radial, SMD/SMT Thru Hole Mounting
• Bulk & Reel
• 1812, 2220, 3225, 4032 Package/Case
Input Inrush Current Limiter
Many items of equipment like switch-mode power supplies, electric motors or transformers exhibit excessive inrush currents when they are turned on, meaning that other components may be damaged or fuses may be tripped. With NTC thermistors, it is possible to effectively limit these currents, at an attractive cost, by connecting a thermistor in series with the load. The NTC thermistors specially developed for this application limit the current at turn-on by their relatively high cold resistance. As a result of the current load the thermistor heats up and reduces its resistance by a factor of 10 to 50; the power it draws reduces accordingly. NTC thermistors are able to effectively handle higher inrush currents than fixed resistors with the same power consumption.
• 1.3A to 123mA Current Rating
• 110VAC to 550VAC
• 1Ω to 500Ω
• 5% to 25% Tolerance
View Input Inrush Current Limiters
Input Filtering
The input EMI Filters, EMI Capacitors, Common Mode Chokes and Input Safety Capacitors all contribute to smoothing the flow of power to the switching transistors in the SMPS. In addition, they prevent the transients caused by the switching transistors from returning to the input power source thereby preventing radiation EMI on the incoming lines.
Input EMC Filters
EPCOS EMC filters, and reactors, ensure electromagnetic compatibility (EMC) with the largest range of products available anywhere including filters designed up to 2500 Amps (or greater upon request) with available voltages from low-voltage applications up to 760 VAC and 1500 VDC. Standard applications for these devices are medical devices, power systems, shielded rooms, frequency converters, solar and other power inverters, UPS systems, and automotive solutions for electric vehicles (EV).
• 250V
• EMC Power Line Filter, 2-line Filter, IEC Inlet Filters
Input EMI & Safety Standard Approved Capacitors
These products are available in Metallized Film and Ceramic and are used mainly in industrial, consumer and lighting applications, e.g. for RFI suppression and prevention of electric shock to humans and animals. The special features of these UL and ENEC certified components are self-extinction and overvoltage security, which is ensured by a special resin filling as well as an "open circuit" failure mode to avoid dangerous shorts. The available categories are X and Y and their subclasses.
• 1000pF to 10µF Capacitance
• 250V to 440VAC Voltage Rating
• 630V to 760VDC Voltage Rating
• 10% to 20% Tolerance
• 10mm to 37.5mm Lead Spacing
• -40°C to 110°C Operating Temperature
Input Common Mode Chokes
Electrical and electronic equipment often generates common-mode interference. In order to remove this interference and meet safety requirements, chokes with a high asymmetrically effective inductance must be used. EPCOS' current-compensated chokes with closed core topology are especially suitable for this purpose. By winding two coils with equal number of turns on the core, it solves the problem of core material saturation. These coils are connected in such a way that the magnetic flux induced by the upper coil is compensated by the lower coil.
• -30% to +50% Tolerance
• 1A to 950mA max DC current
• 1.1Ω to 950mΩ max DC resistance
• -25°C to +125°C operating temp range
PFC & DC Link
The PFC Choke Coils and DC Link Capacitors provide a smooth flow of current and voltage to the switching capacitors which reduces the amount of ripple in the output of the switching transistors. The smoother input also contributes to lower operating temperatures in the active devices.
PFC Choke Coils
• Low height (9.7 to 27mm)
• Large current in a small shape
• Ideal for AV equipment and digital consumer electronics
Aluminum Electrolytic Capacitors
Aluminum Electrolytic Capacitors are lower cost capacitors with relatively shorter life spans and lower ripple current ratings compared to other dielectric types. They are often the correct choice where high capacitance values are needed in given space.
• Single Ended available as:
• High Ripple Current 105°C
• Extended useful life 105°C
• Snap-in available as:
• Ultra compact 85°C
• Long useful life 85°C
• Outstanding ripple current 85°C
• Compact 105°C
• Ultra compact 105°C
View Aluminum Electrolytic Capacitors: Snap-In
DC Film Capacitors
DC Film capacitors are an excellent choice for high reliability applications where ripple current requirements are high, and a high capacitance value is not required. They also may perform better in shock and vibration applications compared to ceramic or aluminum electrolytic options.
• MKT - General purpose
• MKP - High VAC, high temperature
• MKP - Power Factor Correction
• MKP - DC link high power series
• MKP - DC link high density series
Multilayer Ceramic Capacitors (MLCC)
Multilayer ceramic capacitors are excellent choices where a high density of capacitance is required in a very small size.
• LC Series, Commercial, General
• C Series, Commercial, Mid Voltage
• C Series, Commercial, Soft Term
• CKG Series, Automotive, MEGACAP
• CKG Series, Commercial, MEGACAP
• MLCC Radial Lead, Commercial, Mid Voltage
CeraLink™ Capacitors
CeraLink™ is a new ceramic capacitor technology designed for DC link and snubbering applications for high voltage, high ripple current and high temperature applications in a high switching frequency application. Optimal performance is in the 400 - 500VDC operating range and for switching frequencies between 50kHz and 1MHz. They are not recommended for AC applications.
• Low profile 1µF 500V
• Solder Pin 20µF 500V
Conversion and Control
The In-Rush Current Limiters, Thermistors, and Current Sensing Transformers are used in the control circuitry for the switching transistors. The Power Transformers change the voltage and current levels as needed for the input and output transistors.
Inrush Current Limiters
EPCOS brand Inrush Current Limiters are designed to suppress high inrush current surges which can occur when electrical equipment such as SMPS, Motors, Amplifiers, Control Boards, etc.. are powered on. Such high currents are caused by extremely low impedance of smoothing capacitors or coils.
• 1.3A to 123mA Current Rating
• 110VAC to 550VAC
• 1Ω to 500Ω
• 5% to 25% Tolerance
View Input Inrush Current Limiters
Power Transformers
• Clamp, Coil Fomer, EFD Core, ER Core, ETD Core, Pin Coil Former, PQ Core, RM Core, Yoke, Yoke Cover Plates
• 4 to 22 Pins
Thermistors
• 1.8kΩ to 100kΩ
• 60mW to 450mW Power Rating
• 2% to 10% Tolerance
• Radial and Wire Termination Styles
• -55°C to +155°C Operating Temp Range
Current Sensing Transformers
• 6.6mH to 3000uH Inductance
• 320mΩ to 13000mΩ Secondary Resistance
Output Filter & Protection
The output Power Inductors and the Capacitors are used as output EMI filters to prevent switching transients and other EMI artifacts from propagating on the output lines. The output Varistors are used to reduce or eliminate voltage spikes on the output lines.
Output SMT Power Inductors
• 440nH to Inductance
• 7% to 20% Tolerance
• 150mA to Max DC Current
• 1mΩ to Max DC Resistance
• -40°C to +125°C Operating Temperature Range
• 0.001MHz to 0.1MHz Self Resonant Frequency
• Shielded & Unshielded
View Output SMT Power Inductors
Aluminum Electrolytic Capacitors
Aluminum Electrolytic Capacitors are lower cost capacitors with relatively shorter life spans and lower ripple current ratings compared to other dielectric types. They are often the correct choice where high capacitance values are needed in given space.
• Single Ended available as:
• High Ripple Current 105°C
• Extended useful life 105°C
• Snap-in available as:
• Ultra compact 85°C
• Long useful life 85°C
• Outstanding ripple current 85°C
• Compact 105°C
• Ultra compact 105°C
View Aluminum Electrolytic Capacitors
DC Link Capacitors
DC Link capacitors are an excellent choice for high reliability applications where ripple current requirements are high, and a high capacitance value is not required. They also may perform better in shock and vibration applications compared to ceramic or aluminum electrolytic options.
• MKT - General purpose
• MKP - High VAC, high temperature
• MKP - Power Factor Correction
• MKP - DC link high power series
• MKP - DC link high density series
Multilayer Ceramic Capacitors (MLCC)
Multilayer ceramic capacitors are excellent choices where a high density of capacitance is required in a very small size.
• LC Series, Commercial, General
• C Series, Commercial, Mid Voltage
• C Series, Commercial, Soft Term
• CKG Series, Automotive, MEGACAP
• CKG Series, Commercial, MEGACAP
• MLCC Radial Lead, Commercial, Mid Voltage
Output Varistors
EPCOS varistors are the optimum Overvoltage Protection components, ideally suited for limiting surge voltage and current as well as for absorbing energy and ESD Protection. The EPCOS product range includes a variety of Radial Leaded discs, Surface Mount types, Thermal Fused types and special types for Automotive and Telecom applications.
• 5.5V to 745VDC voltage rating
• 4V to 550VAC voltage rating
• 38V to 1.5kV clamping voltage
• 7mm to 21.5mm diameter
• 250A to 12kA peak surge current
• 400mJ to 445J surge energy rating
• 45pF to 7000pF capacitance
• -40°C to +150°C operating temperature range
• Radial, SMD/SMT thru hole mounting
• 1812, 2220, 3225, 4032 package/case