AC to DC power supply with PFC for lamp
First Claim
1. A power supply operable to convert AC sinusoidal voltage in wide range voltage (input voltage) into a constant DC voltage having a predetermined value with Feedback with PFC function or without PFC function. The DC voltage value can be lower than input AC peak voltage or higher than input AC peak voltage or equal to input AC peak voltage. Normal operating without dimming, Vout=rating voltage of lamp;
- Dimming operating, Vout=dimming voltage set by potentiometer. Feedback signal is fed from voltage divider of secondary output voltage to feedback pin of controller 209 as in FIG. 7 or the feedback signal can be coupled to primary from secondary or secondary output voltage divider by opto-coupler, signal transformer, auxiliary winding or digital isolator IC etc and then send to feedback pin of controller 209 as in FIG. 7. Potentiometer (rheostat) voltage divider functions as dimming function and set dimming level. The power supply of claim 1 has one stage converter operable to transfer DC sinusoidal voltage into a DC constant voltage at predetermined value. Before, two stages of converters were applied to realize same function as power supply of claim 1, especially when converting a high input AC sinusoidal line voltage to a low DC constant voltage less than peak input voltage of AC line. The first stage is a boost AC to DC converter that can only convert an Ac input line voltage to a DC constant voltage higher than or equal to input peak voltage of AC line. Boost converter can have PFC or have no PFC function. The second stage is a DC-to-DC converter that can convert a high DC voltage to a low DC voltage. Traditional two stage circuits have higher cost and lower efficiency. So the power supply of claim 1 saves the cost and increases the efficiency to maximum extent.
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Abstract
An AC-to-DC converter with PFC or without PFC generates an output constant voltage at any predetermined value (no matter less or more than input line peak voltage, or even equal to input line peak voltage) with an input line AC voltage with wide range (Typical sinusoidal 110 VAC, 60 Hz or 220 VAC, 50 Hz). It is mainly used as power supply for lamp. Previous power supply for lamp has low frequency component or high frequency component. (1) Low frequency light cause eyes pupil and crystalline lens will adjust 60 times, 120 or many times per second to cause eyes tired. Pupil open wide and crystalline lens adjust to collect more light to focus on retina for seeing clearly at weak light while pupil open narrow and crystalline lens adjust to collect less light to focus on retina at strong light to prevent retina from strong light harm and hurt. In the long run, muscles to control pupil and crystalline lens become very tired and become flabby. Then the muscle can'"'"'t adjust pupil and crystalline according to distance and brightness so that myopia is caused. (2) High frequency voltage causes lamp brightness changes too fast. Eyes can not adjust fast enough to follow the brightness change of lamp for high frequency voltage. But high frequency large current on the secondary cause high EMI that has risk to harm people'"'"'s health. High frequency light causes EMI issue. Peoples'"'"' eyes can'"'"'t keep up with high frequency light. Peak strong light shine on the retina for pupil can'"'"'t shrink at high frequency light. In the long run, retina will be harmed and affect eyesight is affected, cornea dryness or crystalline lens opacity is caused. My invention of power supply lamp has only DC constant voltage on lamp. Lamp'"'"'s brightness is constant and has no low frequency or high frequency component Thus peoples'"'"' eyes and health are protected to maximum extent. The output voltage is regulated at predetermined DC constant value by feedback. You can adjust feedback potentiometer value to set output voltage. Potentiometer and resistor voltage divider with auxiliary winding, (opto-coupler, digital isolator or direct feedback) compose the dimming feedback circuit. It is convenient to adjust the brightness of lamp for eyes'"'"' comfort by adjusting the potentiometer resistance value. My invention can be used directly on second category lamp that doesn'"'"'t need high voltage with ballast to start the lamp. Most of them use heat generated by filament or diode etc to create light. Such as Halogen, Incandescent, LED, PAR lamp, miniature sealed beam lamp, Projection lamp, automotive lamp, some stage and studio lamp, DC fluorescent lamp etc. The converter realized pulse-by-pulse or other current limit protection by sense the current sense resistor or signal transformer.
One stage DC sinusoidal to DC constant converter 206 can be implemented by all kinds of topologies other than the following topologies as long as they can convert DC sinusoidal voltage to DC constant voltage. Buck, Boost, Buck-boost, Noninverting buck-boost ,H-Bridge, Watkins-Johnson, Current-fed bridge, Inverse of Watkins-Johnson, Cuk, SEPIC, Inverse of SEPIC, Buck square, full bridge, half bridge, Forward, Two-transistor Forward, Push-pull, Flyback, Push-pull converter basedon Watkins-Johnson, Isolated SEPIC, Isolated Inverse SEPIC, Isolated Cuk, Two-transistor Flyback etc
One stage AC to DC converter 206 can be realized by discrete components without controller 209, active startup circuit, feedback circuit or sample circuit. Main switch and active startup circuit can be integrated in IC controller. The AC to DC converter is not used only for lamp. It is can also be used for any device requires DC power supply in all the industrial areas. (Telecommunication, Storage, Personal computer, cell phone power supply and charger, video game etc) For example, Bus AC to DC converter, PFC converter, PFC converter for lighting Computer power supply, Monitor power supply, notebook adapter, LCD TV, AC/DC adapter, adjusted voltage charger, Power tool charger, Electronic ballast, Video game power supply etc.
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Citations
20 Claims
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1. A power supply operable to convert AC sinusoidal voltage in wide range voltage (input voltage) into a constant DC voltage having a predetermined value with Feedback with PFC function or without PFC function.
The DC voltage value can be lower than input AC peak voltage or higher than input AC peak voltage or equal to input AC peak voltage. Normal operating without dimming, Vout=rating voltage of lamp; -
Dimming operating, Vout=dimming voltage set by potentiometer. Feedback signal is fed from voltage divider of secondary output voltage to feedback pin of controller 209 as in FIG. 7 or the feedback signal can be coupled to primary from secondary or secondary output voltage divider by opto-coupler, signal transformer, auxiliary winding or digital isolator IC etc and then send to feedback pin of controller 209 as inFIG. 7 .Potentiometer (rheostat) voltage divider functions as dimming function and set dimming level. The power supply of claim 1 has one stage converter operable to transfer DC sinusoidal voltage into a DC constant voltage at predetermined value. Before, two stages of converters were applied to realize same function as power supply of claim 1, especially when converting a high input AC sinusoidal line voltage to a low DC constant voltage less than peak input voltage of AC line. The first stage is a boost AC to DC converter that can only convert an Ac input line voltage to a DC constant voltage higher than or equal to input peak voltage of AC line. Boost converter can have PFC or have no PFC function. The second stage is a DC-to-DC converter that can convert a high DC voltage to a low DC voltage. Traditional two stage circuits have higher cost and lower efficiency. So the power supply of claim 1 saves the cost and increases the efficiency to maximum extent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20)
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18. The AC to DC converter is not used only for lamp. It is can also be used for any device requires DC power supply in all the industrial areas. (Telecommunication, Storage, Personal computer, cell phone power supply and charger, video game etc) For example, Bus AC to DC converter, PFC converter, PFC converter for lighting, Computer power supply, Monitor power supply, notebook adapter, LCD TV, AC/DC adapter, Battery charger, Power tool charger, Electronic ballast, Video game power supply, rotter power supply etc
Specification