In applications where the replacement cost is significantly higher than the cost of an LED bulb - such as street lighting - saving potential available in the installation of maximum historical LED lights are attractive. However, it is important that the power supply for the backlight is designed properly for the expected lifetime is reached.
Looking for help engineers in the market for LED lamps, high bay lights and other LED lighting applications High Power, Power Integrations has launched a reference design intended to reduce component count and size, while improves the efficiency and reliability.
The reference design, called RDR-382, describes a nominal 43V power supply constant for solid state lighting which provides an output of 150 W from an input voltage in the range of 90 to 265V AC current. The design uses HiperPFS-2 PFC controller IC company and its HiperLCS integrated power stage IC LLC. Supply can be used to drive the LED strings single or multiple analog attenuation and allows to be implemented using a 0 to 10V DC input.
The HiperPFS family includes integrated ICs that provide correction active power factor for switching power supplies. The devices allow design factor corrected power rectifier front ends for switching power supplies rated up to 425W universal input applications and up to 900W power supply 230 V AC. The HiperPFS family allows circuits that are easy to design, while improving reliability through design features such as undervoltage protection input, built-in overload protection and thermal shutdown protection hysteresis.
The family combines HiperLCS LLC (two inductors and capacitors) controller, low and high side driver and two half-bridge MOSFETs in one package.
Andrew Smith, senior director of product marketing f
or the company, said: .. "Reliability is especially important for lighting applications with high power output of over 75W Because this design is highly efficient, it generates less heat in combination with a reduced number of components, this ensures a long life. "
Drivers traditional two-stage PFC and LLC stages separated by the company is said to produce a constant voltage output requiring multiple DC / DC converters to create a constant current output. On the contrary, the claims, the reference design RDR-382 uses a new scheme of feedback and control that allows the LLC to provide constant current output directly.
Thus, it is said that the number of components to be cut by approximately 30%, while the efficiency is increased to at least 93%. Meanwhile, the step of removing DC / DC reduces the size of the product. Another contribution to the reduction in size is made by the LLC nominal frequency of 259kHz requires smaller switching magnetism, while the use of a continuous conduction mode, stage PFC variable frequency reduces EMI as compared to an approach fixed frequency, the company adds.
The design is based on HiperPFS PFS7326H device to the front end of PFC and LCS702HG member of HiperLCS range for the output stage LLC.
The front end design comprising: an input filter and the boost converter; EMI filtering and limiting inrush; the main stage PFC; and a supply of main polarization.
In the EMI filtering stage, two capacitors (470nF and 220nF, both 275V) are used to control the differential noise, while a 4.7? 2W winding resistance wire is used for damping, improved power factor and reducing EMI.
Two other 680k? discharge resistors C1 and C2 when the AC supply is disconnected, while a 2.5? NTC thermistor provides inrush limiting. A ceramic capacitor filters common mode EMI 2.2nF, while a 150μH inductor differential mode EMI filters.
On the main stage PFC, a selection of resistance provides output voltage feedback, while a capacitor provides rapid feedback du / dt PFS7326H the feedback pin. This allows the section to handle circuit PFC response to overshoot and undershoot fast. Meanwhile, frequency compensation is provided by two capacitors (2.2μF, 47nF 25V and 50V) and three resistors (6.2k?,? 487k and 3k?). Three additional resistors, filtered through a 22nF capacitor, voltage provided PFS7326H input information.
In the LLC converter stage, the output of the half bridge of a transformer LCS702HG leads through a lock / 8.2nF nominal resonant capacitor, 1000V. The capacitor value was selected for the output ripple current and to withstand high voltages that can occur during a fault.
Transformer, designed to have a leakage inductance of 49μH, in conjunction with series capacitor provides primary resonant frequency to 259kHz. According to the company, this value was found to be an acceptable compromise between the size of the transformer, the output filter capacitance and efficiency. An additional benefit of this frequency is that it allows the use of ceramic capacitors and film.
The output transformer is rectified and filtered by a 150V, 20A Schottky diode, selected for their high efficiency, and two 4.7μF, 63V capacitor dielectric polyester. It interlacing the side halves of the transformers is said to reduce the worst case reverse voltage peak and thus to allow the use of Schottky diode. Additional output filtering is provided by an inductor and a capacitor, which also absorbs peak LLC output impedance.
The output current is sensed through two 0.1? 2W diode resistances subject for 100V, 1A. This is said to prevent damage to the control circuit for a short circuit current output. A shunt resistor and a Zener voltage reference provide an amplifier used as a current sensing operational amplifier. Voltage current detection resistor is applied to the noninverting input of the operational amplifier, which drives an optocoupler.
And a zener diode plus a 10K? sensing resistor providing voltage output to protect the power supply if the output load is removed. Selecting a 10k? resistor and a 39V zener diode is said to provide a smooth voltage limiting feature that helps prevent oscillation in the knee of the curve VI and enhances the features of implementation of supply to the specified LED load.
Meanwhile, a remote adjustment capability is provided by a circuit element comprising two transistors, resistors and a selection of a ceramic capacitor 100nF 50V. A control voltage applied to the circuit current becomes a two 24.9k? resistances and resistance applied to an additional current through a current mirror.This pulls down the reference voltage in the current sensing amplifier and reduces the scheduled output stream. A control voltage of 0 to 10V DC provides an output current range of 100% to 0% to about 20 V to 10 V DC.
The reference design RDR-382 comes with a full description of the power supply LED, together with diagrams of the stages of PFC and LLC, a complete list of materials and upper and lower PCB designs. Testing information supply and mechanical drawings are included engineers provides guidance on building sets sink primary and secondary heat.documents
Looking for help engineers in the market for LED lamps, high bay lights and other LED lighting applications High Power, Power Integrations has launched a reference design intended to reduce component count and size, while improves the efficiency and reliability.
The reference design, called RDR-382, describes a nominal 43V power supply constant for solid state lighting which provides an output of 150 W from an input voltage in the range of 90 to 265V AC current. The design uses HiperPFS-2 PFC controller IC company and its HiperLCS integrated power stage IC LLC. Supply can be used to drive the LED strings single or multiple analog attenuation and allows to be implemented using a 0 to 10V DC input.
The HiperPFS family includes integrated ICs that provide correction active power factor for switching power supplies. The devices allow design factor corrected power rectifier front ends for switching power supplies rated up to 425W universal input applications and up to 900W power supply 230 V AC. The HiperPFS family allows circuits that are easy to design, while improving reliability through design features such as undervoltage protection input, built-in overload protection and thermal shutdown protection hysteresis.
The family combines HiperLCS LLC (two inductors and capacitors) controller, low and high side driver and two half-bridge MOSFETs in one package.
Andrew Smith, senior director of product marketing f
Drivers traditional two-stage PFC and LLC stages separated by the company is said to produce a constant voltage output requiring multiple DC / DC converters to create a constant current output. On the contrary, the claims, the reference design RDR-382 uses a new scheme of feedback and control that allows the LLC to provide constant current output directly.
Thus, it is said that the number of components to be cut by approximately 30%, while the efficiency is increased to at least 93%. Meanwhile, the step of removing DC / DC reduces the size of the product. Another contribution to the reduction in size is made by the LLC nominal frequency of 259kHz requires smaller switching magnetism, while the use of a continuous conduction mode, stage PFC variable frequency reduces EMI as compared to an approach fixed frequency, the company adds.
The design is based on HiperPFS PFS7326H device to the front end of PFC and LCS702HG member of HiperLCS range for the output stage LLC.
The front end design comprising: an input filter and the boost converter; EMI filtering and limiting inrush; the main stage PFC; and a supply of main polarization.
In the EMI filtering stage, two capacitors (470nF and 220nF, both 275V) are used to control the differential noise, while a 4.7? 2W winding resistance wire is used for damping, improved power factor and reducing EMI.
Two other 680k? discharge resistors C1 and C2 when the AC supply is disconnected, while a 2.5? NTC thermistor provides inrush limiting. A ceramic capacitor filters common mode EMI 2.2nF, while a 150μH inductor differential mode EMI filters.
On the main stage PFC, a selection of resistance provides output voltage feedback, while a capacitor provides rapid feedback du / dt PFS7326H the feedback pin. This allows the section to handle circuit PFC response to overshoot and undershoot fast. Meanwhile, frequency compensation is provided by two capacitors (2.2μF, 47nF 25V and 50V) and three resistors (6.2k?,? 487k and 3k?). Three additional resistors, filtered through a 22nF capacitor, voltage provided PFS7326H input information.
In the LLC converter stage, the output of the half bridge of a transformer LCS702HG leads through a lock / 8.2nF nominal resonant capacitor, 1000V. The capacitor value was selected for the output ripple current and to withstand high voltages that can occur during a fault.
Transformer, designed to have a leakage inductance of 49μH, in conjunction with series capacitor provides primary resonant frequency to 259kHz. According to the company, this value was found to be an acceptable compromise between the size of the transformer, the output filter capacitance and efficiency. An additional benefit of this frequency is that it allows the use of ceramic capacitors and film.
The output transformer is rectified and filtered by a 150V, 20A Schottky diode, selected for their high efficiency, and two 4.7μF, 63V capacitor dielectric polyester. It interlacing the side halves of the transformers is said to reduce the worst case reverse voltage peak and thus to allow the use of Schottky diode. Additional output filtering is provided by an inductor and a capacitor, which also absorbs peak LLC output impedance.
The output current is sensed through two 0.1? 2W diode resistances subject for 100V, 1A. This is said to prevent damage to the control circuit for a short circuit current output. A shunt resistor and a Zener voltage reference provide an amplifier used as a current sensing operational amplifier. Voltage current detection resistor is applied to the noninverting input of the operational amplifier, which drives an optocoupler.
And a zener diode plus a 10K? sensing resistor providing voltage output to protect the power supply if the output load is removed. Selecting a 10k? resistor and a 39V zener diode is said to provide a smooth voltage limiting feature that helps prevent oscillation in the knee of the curve VI and enhances the features of implementation of supply to the specified LED load.
Meanwhile, a remote adjustment capability is provided by a circuit element comprising two transistors, resistors and a selection of a ceramic capacitor 100nF 50V. A control voltage applied to the circuit current becomes a two 24.9k? resistances and resistance applied to an additional current through a current mirror.This pulls down the reference voltage in the current sensing amplifier and reduces the scheduled output stream. A control voltage of 0 to 10V DC provides an output current range of 100% to 0% to about 20 V to 10 V DC.
The reference design RDR-382 comes with a full description of the power supply LED, together with diagrams of the stages of PFC and LLC, a complete list of materials and upper and lower PCB designs. Testing information supply and mechanical drawings are included engineers provides guidance on building sets sink primary and secondary heat.documents
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