WO2015136539A1

WO2015136539A1 - Power conversion circuit for driving a group of light emitting diodes

Info

Publication number: WO2015136539A1
Application number: PCT/IL2015/050260
Authority: WO
Inventors: Doron Shmilovitz; Shaul Ozeri; Alexander ABRAMOVITZ
Original assignee: Ramot At Tel-Aviv University Ltd.
Priority date: 2014-03-13
Filing date: 2015-03-12
Publication date: 2015-09-17

Abstract

A power conversion circuit that may include at least one inductor, a switching unit, multiple capacitors and a rectifier for rectifying the alternating input signal; wherein the multiple capacitors comprises a set of isolating capacitors that comprise a first isolating capacitor and a second isolating capacitor; and wherein the set of isolating capacitors is configured to: (a) provide a capacitive isolation barrier between a first input port and a first output port and between a second input port and a second output port; and (b) participate in a resonant or quasi-resonant power conversion across the capacitive isolation barrier.

Description

POWER CONVERSION CIRCUIT FOR DRIVING A GROUP OF LIGHT EMITTING DIODES RELATED APPLICAITONS

[001] This patent application claims the priority of US provisional patent 61/952208 filing date March 13 2014 which is incorporated herein by its entirety.

BACKGROUND OF THE INVENTION

[002] The rapid development of light emitting diode (LED) semiconductor technology over the last decade results in improved brightness and color temperature, lower energy consumption and longer life spans of LED light sources. Commercially available LEDs have an output luminance range of about 150 to 200 lumens/Watt, thus are about five times more efficient than incandescent light sources and more efficient than any other type of light source. The light generation mechanism in LEDs is based on direct conversion of electrical energy into light (throughout the electro-luminescence phenomenon). Therefore they exhibit turn-on/off times on the order of milliseconds and no flicker is observed during turn-on. Moreover, due to being a solid state device (with neither gas nor filament) and due to their relatively low operation temperature, their typical life span should exceed 100,000 hours.

[003] The global world power consumption for lighting would be cut by 50% if all lighting sources were replaced by LEDs. The impact on global world energy saving would be emphasized noting that 15%-20% of the entire energy production is consumed bylighting appliances. The above advantages of LED lighting led industrial, commercial and residential consumers to increasingly adopt LED lights in recent years (the proliferation of LED lighting has been increasing at ~40%/Y).

[004] LED string drivers are ac-dc (or dc-dc) converters which, due the LEDs steep i-v characteristics, should have current source output characteristics. Since the prices of the LED drivers are constantly decreasing, a main objective of this work is a low cost power conversion circuit that features long operating life span, high efficiency, and dimming. High efficiency is particularly important since it allows miniaturization, which for instance allows for fitting in screw-in retrofit LED lamps. Various topologies were proposed for LED drivers, such as buck-boost with inherent Power Factor Correction (PFC), battery operated adaptive boost Error! Reference source not found., series-parallel resonant ac-dc Error! Reference source not found., topologies suitable for high power multi- string LED for street lighting, and light -to-light systems where the LEDs are energized by photovoltaic panels directly (with no battery).

SUMMARY

[005] According to an embodiment of the invention there may be provided power conversion circuits and especially power conversion circuits for driving LEDs - as claimed in the claims and/or illustrated in the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[006] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[007] FIGs 1, 7, 9, 10, 11 and 15-38 illustrate light emitting diodes and power conversion circuits according to various embodiments of the invention;

[008] FIG. 2, 5, 6, 8 and 12-14 illustrates actual or simulated waveforms associated with various power conversion circuits according to various embodiments of the invention;

[009] FIGs 3 and 4 illustrate models of a power conversion circuit according to an embodiment of the invention; and

[0010] Figure 39 illustrates a bridgeless rectifier according to an embodiment of the invention .

[0011] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0013] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings.

[0014] Because the illustrated embodiments of the present invention may for the most part, be implemented using electronic components and circuits known to those skilled in the art, details will not be explained in any greater extent than that considered necessary as illustrated above, for the understanding and appreciation of the underlying concepts of the present invention and in order not to obfuscate or distract from the teachings of the present invention.

[0015] It has been found that a LED driver with no electrolytic capacitor is desirable since it would improve its reliability and reduce its volume. Another component that is relatively expensive and occupies much volume is the transformer. Thus there is provided a LED driver with capacitive coupling instead of traditional magnetic coupling

(transformer).

[0016] The capacitive isolation barrier eliminates the need for a bulky isolation transformer which also reduces the efficiency by 1-2%, and increases the cost.

[0017] Input-output capacitors that cross the safety barrier are well accepted in some ac- dc converters. Those capacitors are connected in across power transformers in order to reduce common mode noise by providing short closing path for the noise. Thus regarding safety standards, capacitive barrier should be acceptable.

[0018] The following power conversion circuits can be classified to resonant, quasi- resonant power conversion circuits. These circuits may achieve low power losses by performing zero current and/or voltage switching.

[0019] The power conversion circuits that are quasi resonant obtain Zero Voltage turn off due to the safety barrier capacitance recharge to the negative value of the output voltage so that the net voltage across the switch is clamped to zero before the turn off instant. Whereas, zero current turn on is obtained due to the inductances totally discharged and no current flowing in any of the resonant components prior to the turn on.

[0020] The power conversion circuits that are resonant or multi-resonant attain zero voltage switching at certain frequency range when the resonant current lags the resonant voltage. In such operation regime, the resonant current flows through an anti-parallel diode of the switch, which, clamps the switch voltage to nearly zero before switch is turned on. Zero voltage turn off of the switch is obtained thanks to switch parasitic capacitance starts charging by the resonant current and its voltage swings from zero voltage towards the rail voltage, at which moment the complementary switch voltage becomes zero , hence, zero voltage turn on can be attained

[0021] Multi Resonant LED driver}

[0022] Figure 1 illustrates a power conversion circuit 1 according to an embodiment of the invention.

[0023] It should noted that the an anti parallel diode can be coupled to Ml. It is not shown for simplisity of explenation.

[0024] The power conversion circuit includes a first input port Pil 21, a second input port Pi2 22, a first output port Pol 23, a second output port Po2 24, an output diode Dol 77, an input inductor Lil 41 and an output inductor Lol 46, an input capacitor Cil 51 and a set of isolating capacitors that includes first and second isolating diodes IC1 61 and IC2 62, a rectifier 81 that is a bridge rectifier that comprises a first rectifier output and a second rectifier output, and a switching unit that is a single switch Ml 31.

[0025] The first and second input ports are configured to receive an alternating input signal. The first and second output ports are configured to provide an output signal to a group of light emitting diodes. The rectifier is for rectifying the alternating input signal.

[0026] A first end of the input inductor is coupled to the first rectifier output and to a first end of the input capacitor.

[0027] A second end of the input inductor is coupled to a first end of the first isolating capacitor and to a first port of the single switch.

[0028] A second end of the first isolating capacitor is coupled to an anode of the output diode and to a first end of the output inductor.

[0029] A second end of the output inductor is coupled to the first output port. [0030] A cathode of the output diode is coupled to the second output port and to a second end of the second isolating capacitor.

[0031] A first end of the second isolating capacitor is coupled to a second end of the single switch, to a second end of the input capacitor and to the second rectifier output.

[0032] This power conversion circuit employs the isolation capacitors both for power transfer and for safety barriers. In addition the converter comprises two inductors, a diode and a MOSFET switch. Due to its low part count and high efficiency, attained by zero- voltage zero-current (ZVS-ZCS) operation, it features miniature size and low cost. Thus, suitable for applications such as screw-in retrofit LED lamps for use in standard incandescent lamps' sockets.

[0033] The power is transferred to the secondary side via a capacitive barrier. The decoupling capacitors' size is limited to a few nano-farads due safety requirements (so that the leakage current from the grid is below 2mA). Nonetheless, these capacitors are an integral part of the resonant converter. Thus, to allow a power transfer of tens of Watts, the small isolation capacitors imply switching frequencies in the 100s of kHz range.

[0034] In order to obtain a high power transfer efficiency (say, >90%) at a relatively high switching frequency, a zero-voltage zero-current switching regime (ZVS-ZCS) is chosen. In order to allow ZVS-ZCS operation, the power is transferred through the series capacitors, C_s, in a charge - total-discharge regime. Moreover, capacitors with a low dissipation factor are desired, such as ceramic capacitors of industry standard COG (NPO) grade (tan δ < 0.1%). The blocking series capacitance is realized by two capacitors in series, in order to isolate both, the phase line and the return line. Herein we analyze the converter's operation assuming a constant input voltage v,-„, and a constant current through the output inductor, L_out. This analysis applies even though v,„ pulsates at 100 Hz, since v,„ barely changes during a switching cycle

[0035] The main waveforms (collectively denoted 2), obtained by PSPICE simulation, are depicted in Figure 2.

[0036] During the first interval, Ati, Ml is on, applying a constant voltage, Vi_n across the input inductor Lil. Thus the inductor's current ramps linearly towards its peak value: in-pk ⁼ {Vin /Lin ) ' At, + i_Lin( 0 ) . If the switch Ml is gated at the zero crossing of the input inductor's current, then

Since both Ml and Dol conduct, the series blocking capacitor IC1 is completely discharged during At . The output inductor feeds the LED group 99 that includes multiple LEDs string, and if chosen sufficiently large, it is only slightly discharged, see Figure 3.

[0037] The second interval, At₂, begins when Ml gate drive is removed. The output diode Dol still conducts, so the right terminal of IC1 is clamped to a zero voltage, see Figure 4. The energy stored in the input inductor starts charging IC1, towards a peak value of: ^Vc_s-_Pk ^{= i}Lin-_Pk z_g~ ^{+ V}in > where Z_g = /(C_s + C_p ) , C_p being the drain source capacitance of Ml plus an additional capacitance required to slow the voltage rise across the MOSFET during turn off.

[0038] The second interval ends (and the third interval At₃ starts) when the output diode stops conducting. This happens when the input inductor's Lil current is lower than the output inductor Lol current. Consequently, the output diode voltage Vd starts to rise and the MOSFET's drain voltage resonates toward zero. The fourth operation interval Δ_-4 starts when the switch drain voltage reaches zero. Consequently, IS l's left terminal is clamped to zero, so it continues to discharge linearly via the output inductor Lol current.

[0039] So far, most of the experiments were conducted on the dc section. The main parameters are: v_in = 100 Vdc, ίϋ=120μΗ, Lol=300 μΗ, ICl=IC2=lnF lkV COG in parallel (AVX Myrtle Beach, SC USA), P_out~12 W, switching frequency /, =200 kHz, Ati=^s The measured efficiency was 92.3%. The main waveforms (5) of the resonant converter are seen in Figure 5, which verifies the ZVS-ZCS operation (note the perfect agreement with the theoretical analysis).

[0040] Figure 6 includes a graphs 6 and 7.

[0041] Graph 6 demonstrates dimming in the range of 3.4W-18W, with quite high linearity with respect to the switching frequency. Efficiency greater than 92% is attained in the range of 5.5W-15.6W. The circuit exhibits a natural tendency to PFC (e.g. without active control of the input current). The input current and input voltage, are shown in graphs 7 of Figure 6. The measure leakage current at 50 Hz was 157 μΑ and the voltage drop 250 mV, well below the limits set by IEC 950 Safety Standards.

[0042] The power conversion circuit contains no transformer; galvanic isolation is attained by a capacitive coupling. The proposed driver includes no electrolytic capacitors - saving space and improving reliability and life time expectancy. [0043] The converter exhibits inherent PFC feature, but a controller may be used to further improve the ac line interface. The theoretical analysis was verified by simulation and experiments displayed a typical efficiency above 92% and a reasonable dimming range.

[0044] The leakage current was well below the safety limits in all operating conditions.

[0045] The power conversion circuit described above is also applicable generally to single-stage PFC, dual-stage PFC, and dc-dc converter 7, as illustrated in the figure 7.

[0046] Controller

[0047] Figures 9-10 illustrate a power conversion circuit and a controller according to an embodiment of the invention. Figure 8 illustrates simulated results of various signals obtained when controlling the power conversion circuit by the controller according to an embodiment of the invention.

[0048] The controllers of figure 9 and 10 differ by their detectors and sensors. It is noted that the sensor and the detectors of figures 8 and 9 and interchangeable.

[0049] In order to provide an effective operation in a burst mode and a continuous mode of said quasi-resonant converter operation a controller that provides a soft switching operation is needed. The soft switching controller includes a sensor and a detector.

[0050] An input of the sensor is connected to a drain of switch Ml or could be connected to an auxiliary winding of resonant inductor LI. The purpose of the sensor is to provide a trigger signal to detector according to a valley or DC voltage on Ml drain. There are two versions of sensor with and without prediction of valley voltages, Sensor 1 and Sensor2 accordingly. Sensor 1 could provide a delay less operation of controller to reduce switching and conductive losses in the converter.

[0051] The output of sensor connected to the detector. Besides the detector has an input clock signal and a driver output signal. The purpose of detector is to detect valley or DC events, synchronize the converter operation with input clock signal, and latch ON state till OFF state that received by means of clock signal. The clock signal could be already modulated according a burst mode. There are two general versions of detector. The output of detector is connected to driver of semiconductor switch Ml.

[0052] Basic Quasi Resonant LED Driver [0053] Figure 11 illustrates a power conversion circuit 111 according to an embodiment of the invention.

[0054] The power conversion circuit includes an input inductor Lil 41, an output inductor Lol 46, an input capacitor Cil 51, an output capacitor Col 56 and the set of isolating capacitors (of IC1 61 and IC2 62), a rectifier 81 that is a bridge rectifier that comprises a first rectifier output and a second rectifier output, a switching unit that is a single switch Ml 31, an input diode Dil 71, a first output diode Dol 76 and a second output diode Do2 77.

[0055] The power conversion circuit 111 also includes first and second input ports Pil 21 and Pi2 22 that are configured to receive an alternating input signal, and first and second output ports Po 1 23 and Po4 24 that are configured to provide an output signal to a group of light emitting diodes 99.

[0056] The rectifier 81 is for rectifying the alternating input line voltage.

[0057] An anode of the input diode is coupled to the first rectifier output and to a first end of the input capacitor. A cathode of the input diode is coupled to a first end of the input inductor. A second end of the input inductor is coupled to a first end of the first isolating capacitor and to a first port of the single switch. A second end of the first isolating capacitor is coupled to an anode of the first output diode and to a cathode of the second output diode. An anode of the second output diode is coupled to a first end of the output inductor. A cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port. A second end of the output capacitor is coupled to the second output port, to a second end of the output inductor and to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a second end of the single switch, to a second end of the input capacitor and to the second rectifier output.

[0058] Switch Ml conduction charges the input inductor Lil while at the same time the capacitor IC1 and IC2 discharge and transfer the stored energy to output inductor Lol. Lo 1 inductor then transfers the energy to the output via Do 1. When the switch is turned off the input inductor Lil discharges into IC1 and IC2. The input diode Dil blocks the reverse current flow so IC1 and IC2 remain charged till the switch is turned on in the successive switching cycle. Since the current of Lil is nearly proportional to the input voltage the circuit emulates a resistive load towards the line.

[0059] The power conversion circuit 111 operates with small IC1 and IC2 capacitors value. These capacitors present high impedance at the line frequency and limit the current that can flow from the line to human body in case of accidental contact with the appliance.

[0060] Figure 12-14 illustrate simulation results for various signals of the power conversion circuit according to an embodiment of the invention.

[0061] Simplified Quasi Resonant LED Driver.

[0062] Figure 15 illustrates a power converting circuit 112 according to an embodiment of the invention.

[0063] Power conversion circuit 112 of figure 15 differs from power covnersion circuit 111 of figure 11 by not including the second output diode. This configuration has less conduction losses but at the expense of somewhat increased parasitic oscillation.

[0064] Basic Bridgeless Quasi Resonant LED Driver

[0065] The power conversion circuit 131 of figure 16 includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol and Po2 23 and 24, a first output diode Dol 76, a second output diode Do2 77, an input inductor Lil 41 and an output inductor Lol 46, an input capacitor Cil 51, an output capacitor Col 56 and a set of isolating capacitors IC1 61 and IC2 62.

[0066] The rectifier is a bridgeless rectifier and comprises a first input diode Dil 71 and a second input diode Dil 72.

[0067] The switching unit is a pair of switches Ml 31 and M3 32 that are arranged in a totem pole arrangement are also a part of the bridgeless rectifier circuit.

[0068] A first end of the input inductor is coupled to the first input port. A second end of the input inductor is coupled to an anode of the first input diode and to a cathode of the second input diode. A cathode of the first input diode is coupled to a first output port of the switching unit and to a first end of the first isolating capacitor. An anode of the second input diode is coupled to a second port of the switching unit and to a first end of the second isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode and to a cathode of the second output diode. An anode of the second output diode is coupled to a first end of the output inductor. A cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port. A junction between the pair of switches is coupled to the second input port. A second end of the output capacitor is coupled to the second output port, to a second end of the output inductor and to a second end of the second isolating capacitor.

[0069] Power conversion circuit 131 differs from power conversion circuit 111 by a relocation of Lil to the line side and using the active switches Ml and M2 also as a part of the rectifier circuit. Depends on the polarity of the line voltage one of the transistors conducts throughout a half the line cycle while the other is switched at high frequency to govern the charging and discharging of Lil. The switches interchange their roles in the successive half line cycle. The voltage drop and, thus, conduction losses, of the switch are generally lower than that of a diode, hence, the converter can have better efficiency.

[0070] Simplified Bridgeless Quasi Resonant LED Driver

[0071] Figure 17 illustrates a power converting circuit 132 according to an embodiment of the invention.

[0072] Power conversion circuit 132 of figure 17 differs from power covnersion circuit 131 of figure 16 by not including the second output diode. This configuration has less conduction losses but higher parasitic oscillation can be observed.

[0073] Bridgeless Quasi Resonant LED Driver with Split Output Inductors

[0074] Another version of this circuit can be included where the inductors Lo 1 and Lo2 are coupled to each other can be reffered to as Bridgeless Quasi Resonant LED Driver with Coupled Inductors

[0075] Figure 18 illustrates power convertign circuit 140 according to an embodiment of the invention.

[0076] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an input inductor Linl 41, an output inductor Lol 46, an additional output inductor Lo2 47, a first output diode Dol 76, a second output diode Do2 77, an output capacitor Col 56 and the set of isolating capacitors that includes a first and second isolating capacitors IC1 61 and IC2 62. [0077] The rectifier 81 is a bridgeless rectifier and comprises a first input diode and a second input diode.

[0078] The switching unit is a pair of switches Ml 31 and M3 32 that are arranged in a totem pole arrangement.

[0079] A first end of the input inductor is coupled to the first input port. A second end of the input inductor is coupled to an anode of the first input diode and to a cathode of the second input diode. A cathode of the first input diode is coupled to a first output port of the switching unit and to a first end of the first isolating capacitor. An anode of the second input diode is coupled to a second port of the switching unit and to a first end of the second isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode and to a first end of the additional output inductor. A second end of the output inductor is coupled to a second end of the second isolating capacitor and to a cathode of the second output diode. A second end of the additional output inductor is coupled to an anode of the second output diode, to the second output port and to a second end of the output capacitor. A junction between the pair of switches is coupled to the second input port. A cathode of the first output diode is coupled to a first end of the output inductor, to the first output port and to a first end of the output capacitor.

[0080] Lil is charged via a loop that includes Lil, Dil, Ml and M2.

[0081] When both switches Ml and M2 conduct IC1 and IC2 are discharged by discharge loop that includes IC1, Lo2, Col Lol, IC2, Ml and M2 - against an equivalent inductance, which equals the sum of Lol and Lo2. Hence, lower discharge current can be attained which also helps attaining lower switch current. The inductances are discharged in parallel towards the output filter Col so their discharge time is relatively short.

Consequently, this circit can operate at higher switching frequency.

[0082] Quasi Resonant LED Driver with Split Output Inductors

[0083] Figure 19 illustrates power conversion circuit 212 according to an embodiment of the invention.

[0084] The power conversion circuit 212 includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an input inductor Lil 41 41, an output inductor Lol 46 and an additional output inductor Lo2 47, a first input diode Dil 71, a first output diode Dol 76, a second output diode Do2 77, an input capacitor Cil 51, an output capacitor C01 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[0085] The rectifier 81 is a bridge rectifier and comprises a first rectifier output and a second rectifier output.

[0086] The switching unit is a single switch.

[0087] Lil 41 is charged via a loop that includes Dil 71, Lil 41, Ml and Cil 51. Lol 46 is discharged via a loop that includes Lol 46 Dol 76 and Col 56. Lo2 47 is discharged by a pool that includes Lo2 47, Col 56 and Do2 77.

[0088] When the switch Ml conducts both IC1 and IC2 are discharged against an equivalent inductance, which equals the sum of of Lol 46 and Lo2 47 and via Col 56. The capacitors' discharge loop includes Ml, IC2, Lo2 47, Col 56, Lol 46 and IC1. Hence, lower discharge current can be attained which also helps attaining lower switch current. The inductances Lol 46 and Lo2 47 are discharged in parallel towards Col 56 so their discharge time is shorter then would be with a single inductor. Consequenlty, higher switching frequency is possible.

[0089] An anode of the input diode is coupled to the first rectifier output and to a first end of the input capacitor. A cathode of the input diode is coupled to a first end of the input inductor. A second end of the input inductor is coupled to the first end of the first isolating capacitor and to a first port of the single switch. A second end of the first isolating capacitor is coupled to an anode of the second output diode and to a first end of the output inductor. A cathode of the second output diode is coupled to a first end of the additional output inductor, to the second output port and to a first end of the output capacitor. A second end of the additional output inductor is coupled to a second end of the second isolating capacitor and to a cathode of the first output diode. A second end of the output inductor is coupled to an anode of the first output diode, to the first output port and to a first end of the output capacitor.

[0090] Switched Capacitor Quasi Resonant LED Driver. [0091] Figure 20 illustrates power conversion circuit 220 according to an embodiment of the invention. [0092] The power conversion circuit 220 includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an output inductor Lo 1 46, a first output diode Do 1 76, a second output diode Do2 77, an input capacitor Cil 51, an output capacitor Col 56 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[0093] This power conversion circuit includes a single switched capacitor cell assisted with a Lol 46 (that acts as a resonant inductor) to attain zero current lossless switching. The power conversion circuit uses a half wave output rectifier. Turn on of the lower switch M2 generates a sinusoidal current pulse which charges IC 1 and IC2 - via a loop that includes IC1, Lol 46, Dol 76, Col 56, IC2 and M2. Turning on of the higher switch Ml allows resonant discharge via a loop that includes Ml, IC1, Lol 46, Do2 77 and IC2.

[0094] The rectifier 81 is a bridge rectifier and comprises a first rectifier output and a second rectifier output. The switching unit Ml, M2 is a pair of switches that are arranged in a totem pole arrangement.

[0095] A first end of the input capacitor is coupled to the first rectifier output, to a first port of the switching unit and to a first end of the first isolating capacitor. A second end of the input capacitor is coupled to the second input port and to a second port of the switching unit. A second end of first isolating capacitor is coupled to a first end of the output inductor. A second end of the output inductor is coupled to an anode of the first output diode and to a cathode of the second output diode. A cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port. The second output port is coupled to a second end of the output capacitor, to an anode of the second output diode and to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a junction between the pair of switches.

[0096] According to another embodiment of the invention this power conversion circuit is modified so that IC 1 , IC2 and the rest of the output circuit are connected in parallel with M2 (simlar to Fig 21 ) .

[0097] Switched Capacitor Quasi Resonant LED Driver with Full Wave Rectifier.

[0098] Figure 24 illustrates power conversion circuit 230 according to an embodiment of the invention. [0099] This power conversion circuit may include of a single switched capacitor cell assisted with Lo 1 46 that acts as a resonant inductor to attain zero current lossless switching. The power conversion circuit uses an output rectifier 82 that is a bridge rectiifer.

[00100] The power conversion circuit 230 includes first and second input ports Pil 21 and Pi2 22, an input rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an output inductor Lo 1 46, an output bridge rectifier 81 , an input capacitor Cil 51, an output capacitor Col 56 and the set of isolating capacitors that includes first and second isolating capacitors IC 1 61 and IC2 62.

[00101] The input rectifier 81 is a bridge rectifier.

[00102] The switching unit is a pair of switches Ml 31 and M3 32 that are arranged in a totem pole arrangement.

[00103] Turning on of the lower switch M2 generates a sinusoidal current pulse which charges the CI, C2 capacitor pair - via a first loop that includes IC1, Lol 46, output rectifier, IC2 and M2 - and via a second loop that includes IC1, Lol 46, output rectifier, LED, IC2 and M2

[00104] Turning on of the higher switch Ml allows resonant discharge via a loop that includes IC1, Lol 46, output rectifier, LED, Col 56, output rectifier, IC2 and M2.

[00105] A first end of the input capacitor is coupled to a first output port of the input rectifier, to a first port of the switching unit and to a first end of the first isolating capacitor. A second end of the input capacitor is coupled to a second output port of the input rectifier and to a second output port of the switching unit. A second end of first isolating capacitor is coupled to a first end of the output inductor. A second end of the output inductor is coupled to a first input port of the output rectifier. A first end of the output capacitor is coupled to the first output port of the power conversion circuit and to a first output port of the output rectifier. A second end of the output capacitor is coupled to the second output port of the power conversion circuit and to a second output port of the output rectifier. A second end of the second isolating capacitor is coupled to a second input port of the output rectifier. A first end of the second isolating capacitor is coupled to a junction between the pair of switches. [00106] According to another embodiment of the invention this power conversion circuit is modified so that IC1, IC2 and the rest of the output circuit are connected in parallel with Ml (simlar to Fig 20).

[00107] Switched Capacitor Quasi Resonant LED Driver with Input Inductor [00108] Figure 22 illustrates power conversion circuit 240 according to an embodiment of the invention.

[00109] The power conversion circuit 240 includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an input inductor Lil 41, an output inductor Lol 46, a first output diode Dol 76, a first input diode Dil 71, an input capacitor Cil 51, an output capacitor Col 56 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62. The circuit is provided with a line rectifier 81 which is a bridge rectifier. The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00110] This power conversion circuit 260 {240?} creates a converter with a single switched capacitor cell assisted with Lil 41 that acts as a resonant inductor at the high side to attain zero current lossless switching. The power conversion circuit uses a half wave output rectifier with second order output filter that includes Lol 46 and Col 56.

[00111] Turning on of the high switch Ml generates a sinusoidal current pulse which charges IC1 and IC2. This includes a loop of Dil 71, Lil 41, , IC1, Dol 76, IC2 and the ground.

[00112] Turning on of the lower switch M2 allows resonant discharge. This may be done in a loop that includes M2, IC2, Col 56, Lol 46 and IC1.

[00113] Due to discontinuous input current the input current pulses are nearly proportional with the input voltage so the converter has resistive input characteristics. This helps attaining low harmonics and high power factor of the line current.

[00114] A first end of the input capacitor is coupled to a first output port of the rectifier and to an anode of the input capacitor. A cathode of the input diode is coupled to a first end of the input inductor. A second end of the input inductor is coupled to a first port of the switching unit. A junction between the pair of switches is coupled to a first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the output diode and to a first end of the output inductor. A second end of the output inductor is coupled to the first output port and to a first end of the output capacitor. A second end of the output capacitor is coupled to the second output port, to a cathode of the output diode and to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a second port of the switching unit.

[00115] According to another embodiment of the invention this power conversion circuit is modified so that IC1, IC2 and the rest of the output circuit are connected in parallel with Ml.

[00116] Switched Capacitor Quasi Resonant LED Driver with Input Inductor and Split Output Inductors

[00117] Figure 23 illustrates a power converting circuit 270 according to an embodiment of the invention.

[00118] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an input inductor Lil 41, an output inductor Lol 46 and an additional output inductor Lo2 47, an input capacitorCil 51, an output capacitor Col 56 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62, a first output diode Dol 76, a second output diode Do2 77 and a first input diode Dil 71.

[00119] The rectifier 81 is a bridge rectifier.

[00120] The switching unit is a pair of switches Ml 31 and M3 32 that are arranged in a totem pole arrangement.

[00121] This power conversion circuit has a single switched capacitor cell assisted with a resonant inductor Lil 41 at the high side to attain zero current lossless switching. The power conversion circuit uses a half wave output rectifier with split inductor filter Lol 46, Lo2 47-Col 56. Turn on of the high switch Ml 31 generates a sinusoidal current pulse which charges the IC1 and IC2 capacitor pair. Turn on of the lower switch M2 32 allows resonant discharge.

[00122] Due to discontinuous input current the input current pulses are nearly proportional with the input voltage so the converter has resistive input characteristics. This helps attaining low harmonics and high power factor of the line current. [00123] A first end of the input capacitor is coupled to a first output port of the rectifier and to an anode of the input capacitor. A cathode of the input diode is coupled to a first end of the input inductor.

[00124] A second end of the input inductor is coupled to a first port of the switching unit. A junction between the pair of switches is coupled to a first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode and to a first end of the additional output inductor. A second end of the additional output inductor is coupled to the first output port, to a first end of the output capacitor and to an anode of the output capacitor. A second end of the output capacitor is coupled to the second output port, to a cathode of the first output diode and to a first end of the output inductor. A cathode of the second output diode is coupled to a second end of the additional output inductor and to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a second port of the switching unit .

[00125] According to an embodiment of the invention the output inductors are coupled.

[00126] Switched Capacitor Quasi Resonant LED Driver with an Assisting Inductor

[00127] Figure 21 illustrates a power converting circuit 230 according to an embodiment of the invention.

[00128] This power converting circuit is further derivation of power conversion circuit 250. The modification includes in application of a full wave output rectifier 82.

[00129] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, an input rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an output inductor Lo 1 46, an output rectifier 82 that is a bridge rectifier, an input capacitor Cil 51, an output capacitor Col 56 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[00130] The input rectifier 81 is a bridge rectifier.

[00131] The switching unit is a pair of switches Ml 31 and M3 32 that are arranged in a totem pole arrangement. [00132] A first end of the input capacitor is coupled to a first output port of the input rectifier. A second end of the input capacitor is coupled to a second output port of the input rectifier and to a second output port of the switching unit. A second end of first isolating capacitor is coupled to a first input port of the output rectifier. A first end of the output inductor is coupled to the first output port of the output rectifier. A second end of the output inductor is coupled to a first end of the output capacitor and to the first output port of the power conversion circuit. A second end of the output capacitor is coupled to a second output port of the output rectifier. A second input port of the output rectifier is coupled to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a second port of the switching unit.

[00133] Asymetric Half Bridge CLLC Resonant LED Driver

[00134] Figure 25 illustrates a power conversion circuit 120 according to an embodiment of the invention.

[00135] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, an output inductor Lol 46 and an additional output inductor Lo2 47, a first output diode Dil 71, a second output diode Di2 72, an input capacitor Cil 51, a first output capacitor Col 56, a second output capacitor Co2 57 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[00136] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00137] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00138] A first end of the input capacitor is coupled to the first rectifier output and to a first port of the switching unit. A second end of the input capacitor is coupled to the second rectifier output and to a second port of the switching unit. A junction that is coupled between the pairs of switches is coupled to a first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the output inductor. A cathode of the first output capacitor is coupled to a first end of a first output capacitor and to the first output port. A second end of the first output capacitor is coupled to a second end of the output inductor, to a first end of the second output capacitor and to a first end of the additional output inductor. A second end of the second output capacitor is coupled to the second output port and to an anode of the second output diode. A first end of the additional output inductor is coupled to a second end of the second isolating capacitor. A first end of the second isolating capacitor is coupled to a second port of the switching unit and to the second output port of the rectifier.

[00139] This power conversion circuit is derived from the LLC resonant converter and is designed to operate at high switching frequency of xlOOkHz and possibly xMhz range. The converter operates off the rectified line voltage. Here the IC1 and IC2 act as an equivalent resonant capacitor. The small value of Icl andlc2 capacitors present high impedance at the line frequency and limit the current that can flow from the line to human body in case of accidental contact with the appliance. Therefore Icl Ic2 pair comprise the capacitive isolation barier

[00140] Application of the doubler rectifier Dol, Do2 with split capacitor output filter Col, Co2 helps lowering the conduction losses since only one diode is in the conduction path.

[00141] Asymetric Half Bridge LCCC Resonant LED Driver with Integrated Power Factor Corrector

[00142] Figure 26 illustrates a power conversion circuit 150 according to an embodiment of the invention.

[00143] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, a first input inductor Lil 41, a second input inductor Li2 42 and a third input inductor Li3 43, a first input diode Dil 71, a second input diode Di2 72, a third input diode Di3 73, a first output diode Dol 76, a second output diode Do2 77, a third output diode Do3 78, a first input capacitor Cil 51, a second input capacitor Ci2 52, a third input capacitor Ci3 53, a first output capacitor Col 56, a second output capacitor Co2 57, a third output capacitor Co3 58 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62. [00144] The resonant capacitors IC1 and IC2 create capacitive isolation characteristic, as mentioned above. The output rectifier is of the doubler type to reduce the conduction losses, also as mentioned above.

[00145] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00146] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00147] A first end of the first input capacitor is coupled to the first rectifier output and to an anode of the first input diode. A second end of the first input capacitor is coupled to a first end of the second capacitor, to a junction between the pair of switches and to a first end of the second input inductor. A second end of the second input capacitor is coupled to the second rectifier output and to a cathode of the second input diode. A cathode of the first input diode is coupled to a first end of the first input inductor. A second end of the first input inductor is coupled to a first port of the switching unit and to a first port of a third input diode. An anode of the second input diode is coupled to a first end of the third input inductor. A second end of the third input inductor is coupled to a second port of the switching unit, to a second end of the third input capacitor and to a second end of the second isolating capacitor. A second end of the second input inductor is coupled to a first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor. A cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A cathode of the third output diode is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the third output capacitor.

[00148] Half Bridge LCCC Resonant LED Driver

[00149] Figure 27 illustrates a power conversion circuit 160 according to an embodiment of the invention.

[00150] This circuit is derived from LCC resonant converter by splitting the resonant capacitor into two IC1 and IC2 to create the capacitive isolation barrier feature. [00151] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, a first input inductor Lil 41, a first input capacitor Cil 51, a second input capacitor Ci2 52, a first output capacitor Col 56, a second output capacitor Co2 57, a third output capacitor Co3 58and the set of isolating capacitors that includes first and second isolating capacitors ICl 61 and IC2 62, a first output diode Dol 76, a second output diode Do2 77 and a third output diode Do3 78.

[00152] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00153] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00154] A first end of the first input capacitor is coupled to the first rectifier output and to a first port of the switching unit. A second end of the first input capacitor is coupled to a first end of the second capacitor and to a first end of a third input capacitor. A junction between the pair of switches is coupled to a first end of the first input inductor. A second end of the switching unit is coupled to the second rectifier output and to a second end of the second input capacitor. A second end of the first input inductor is coupled to a first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor. A cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A cathode of the third output diode is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the third output capacitor.

[00155] Half Bridge CLLC Resonant LED Driver

[00156] Figure 28 illustrates a power conversion circuit 170 according to an embodiment of the invention.

[00157] This converter is derived from LLC resonant converter by splitting the resonant capacitance into two to create capacitive isolation barrier. [00158] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a first output diode Dil 71, a second output diode Di2 72, a switching unit, first and second output Pol 23 and Po2 24, a first input inductor Lil 41, a first output inductor Lol 46 46 and a second output inductor Lo2 47, a first input capacitor Cil 51, a second input capacitor Ci2 52, a first output capacitor Col 56, a second output capacitor Co2 57 and the set of isolating capacitors that includes a first isolating capacitor IC1 61 and a second isolating capacitor IC2.

[00159] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00160] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00161] A first end of the first input capacitor is coupled to the first rectifier output and to a first port of the switching unit. A second end of the first input capacitor is coupled to a first end of the second capacitor and to a first end of the second isolating capacitor. A junction between the pair of switches is coupled to a first end of the first isolating capacitor. A second end of the switching unit is coupled to the second rectifier output and to a second end of the second input capacitor. A second end of the second isolating capacitor is coupled to a first end of the first output inductor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the second output inductor. A cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A second end of the second output inductor is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the first output inductor.

[00162] Half Bridge LCCC Resonant LED Driver with Charge Pump Power Factor Corrector

[00163] Figure 29 illustrates a power conversion circuit 180 according to an embodiment of the invention. [00164] This circuit is derived from LCC resonant converter and includes also charge pump power factor corrector circuit. The power factor corrector's charge pump capacitor Ic2 is driven by the resonant circuit.

[00165] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, a first input inductor Lil 41, a first input diode Dil 71, a second input diode Di2 72, a first output diode Dol 76, a second output diode Do2 77, a third output diode Do3 78, a first input capacitor Cil 51, a second input capacitor Ci2 52, a first output capacitor Col 56, a second output capacitor Co2 57, a third output capacitor Co3 58 and the set of isolating capacitors that includes a first isolating capacitor IC1 61, a second isolating capacitor IC2 62, which also functions as the charge pump, and a third isolating capacitor IC3 63.

[00166] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00167] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00168] A first end of the first input capacitor is coupled to the first rectifier output and to an anode of the first input diode. A second end of the first input capacitor is coupled to a first end of the second isolating capacitor, to a second end of the third isolating capacitor, to a second port of the switching unit and to second end of the second input capacitor. An anode of the second input diode is coupled to a cathode of first input diode and to a first end of the second isolating capacitor. A cathode of the second input diode is coupled to a first port of the switching unit and to a first end of the second input capacitor. A second end of the third isolating capacitor is coupled to a first end of the third isolating capacitor, to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor. A cathode of the first output diode is coupled to a first end of a first output capacitor. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A second end of the third output capacitor is coupled to the first end of the first isolating capacitor, to the first output port and to a second end of the first output capacitor. [00169] Buck Boost PFC LC3

[00170] Figure 30 illustrates a power conversion circuit according to an embodiment of the invention.

[00171] This circuit is a hybrid of a buck boost pfc rectifier and a LCC resonant converter with capacitive isolation.

[00172] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, a first input diode Dil 71, a second input diode Di2 72, a third input diode Di3 73, a first output diode Dol 76, a second output diode Do2 77, a first input inductor Lil 41 and a second input inductor Li2 42, a first input capacitor Cil 51, a first output capacitor Col 56, a second output capacitor Co2 57, a third output capacitor Co3 58 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[00173] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00174] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00175] A first end of the first input inductor is coupled to the first rectifier output and to an anode of the first input diode. A cathode of the first input diode is coupled to a first end of the first input capacitor and to a first port of the switching unit. A second port of the switching unit is coupled to a second end of the first input capacitor, to an anode of the third input diode and to a first end of the second isolating capacitor. An anode of the second input diode is coupled to a first switch of the pairs of switches, to a cathode of the third input diode and to a first end of the second input inductor. A cathode of the second input diode is coupled to a second switch of the pairs of switches and to the second rectifier output. A second end of the second input inductor is coupled to the first end of the first isolating capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor. A cathode of the first output diode is coupled to a first end of a first output capacitor. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A second end of the third output capacitor is coupled to the first end of the second isolating capacitor, to the first output port and to a second end of the first output capacitor.

[00176] Asymetric Half Bridge LCCC Resonant LED Driver with Integrated Buck Boost Power Factor Corrector

[00177] Figure 31 illustrates a power conversion circuit 200 according to an embodiment of the invention.

[00178] This converter is a hybrid of buck boost pfc rectifier and a LLC resonant converter with capacitive isolation.

[00179] The power conversion circuit includes first and second input ports Pil 21 and Pi2 22, a rectifier 81, a switching unit, first and second output ports Pol 23 and Po2 24, a first input diode Dil 71, a second input diode Di2 72, a third input diode Di3 73, a first output diode Dol 76, a second output diode Do2 77, a first input inductor Lil 41, a first output inductor Lol 46 and a second output inductor Lo2 47, a first input capacitor Cil 51 and the set of isolating capacitors that includes first and second isolating capacitors IC1 61 and IC2 62.

[00180] The rectifier 81 is a bridge rectifier that comprises a first rectifier output and a second rectifier output.

[00181] The switching unit is a pair of switches Ml 31 and M2 32 that are arranged in a totem pole arrangement.

[00182] A first end of the first input inductor is coupled to the second rectifier output and to an anode of the first input diode. A cathode of the first input diode is coupled to a first end of the first input capacitor and to a first port of the switching unit. A second port of the first input inductor is coupled to a second port of the switching unit, to a second end of the first input capacitor, to an anode of the third input diode and to a first end of the second isolating capacitor. An anode of the third input diode, a cathode of the second input diode and a first switch of the pair of switches are coupled to a first port of the first isolating capacitor. A second end of the second isolating capacitor is coupled to a first end of a second output capacitor. A second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the first output inductor. A cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port. An anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port. A second end of the first output inductor is coupled to the second end of the second output inductor, to a second end of the first output capacitor and to a first end of the second output capacitor. A cathode of the second input diode is coupled to the first rectifier output and to a second switch of the pair of switches.

[00183] Additional configurations

[00184] Figure 32 illustrates power conversion circuit 330 according to an embodiment of the invention.

[00185] Power conversion circuit 330 differs from power conversion circuit 111 by illustrating rectifier 61 as including input diodes Dil - Dil4 71-74, and by not having a diode between Cil 51 and Lil 38.

[00186] Figure 33 illustrates power conversion circuit 337 according to an embodiment of the invention.

[00187] Power conversion circuit 337 differs from power conversion circuit 330 by having a pair of switches Ml 31 and M2 32 instead of single switch Ml 31, by coupling input diode Di3 73 in parallel to Ml 31 and by coupling input diode Di4 74 in parallel to M2 32.

[00188] Figure 34 illustrates power conversion circuit 350 according to an embodiment of the invention.

[00189] Power conversion circuit 350 differs from power conversion circuit 337 by not including seocnd output diode Do2 47 in series to first output inductor Lol 46.

[00190] Figure 35 illustrates power conversion circuit 360 according to an embodiment of the invention.

[00191] Power conversion circuit 360 differs from power conversion circuit 337 by:

a. Having Lo2 47 coupled in series to Do2 77, wherein Lo2 47 and Do2 are coupled in parallel to IC1 and IC2 (instead of having Col coupled between Ic2 and the output of Dol)

b. LED 99 and Col 56 are coupled in parallel to each other and in series between the cathode of Dol 76 and tje anode of Do2 77. [00192] Figure 36 illustrates power conversion circuit 370 according to an embodiment of the invention.

[00193] Power conversion circuit 370 differs from power conversion circuit 350 by having output inductor Lo2 47, wherein Lol and Lo2 form a l:m transformer.

[00194] Figure 37 illustrates power conversion circuit 380 according to an embodiment of the invention.

[00195] Power conversion circuit 380 differs from power conversion circuit 350 by having a second output inductor Lo2 47 connected between IC1 61 and the anode of Dol 76.

[00196] Figure 38 illustrates power conversion circuit 390 according to an embodiment of the invention.

[00197] Power conversion circuit 390 differs from power conversion circuit 380 by having, in parallel to LE9 99, a unit that includes (i) a synchronization circuit (SYNC) 92 that is fed from the junction that connects Lol to Lo2, (2) a third switch M3 that is fed by SYNC and has a diode Dol between the source and gate of the thirs switch M3- the anode of Dol is connected to IC2.

[00198] Figure 39 illustrates a bridgeless rectifier 400 according to an embodiment of the invention. This rectifer may replace otehr rectifiers illustrated above.

[00199] In power conversion circuit 111 may be need to satisfy conflicting requirements. In order to keep the resonant discharge current in the IC1 Lol loop and, consequently, switch conduction losses as well as Lol core losses at an acceptable level, the inductor Lol has to be sufficiently large. However, a higher value of Lol results in a long discharge time towards Col. The later feature is undesirable since it limits the switching frequency and converter's output power. To overcome this limitation several options can be considered as shown in figures 360, 370 and 380. The idea behind these circuits is presenting a sufficiently large inductance in the ICl-Lol path but a low inductance in the Lol-Col path. The power conversion circuit 360 has a current doubler rectifier variant accomplishes the IC1 - Lol discharge via 2Lol series equivalent, whereas Lo's discharge into Col is realized in parallel. An additional advantage of this circuit is having only one diode drop in the discharge path to the output. Double isolated power conversion circuit 370 uses a coupled inductor and due to its turn ratio attains high inductance at the primary and low inductance at the secondary circuits. Additional advantages here are lower voltage stress of the output rectifier Dol and increased isolation rating. Similar idea can be implemented with a non-isolated coupled inductor as shown in figure 38. This circuit (380) has the advantage of lesser core volume due to simplified inductor structure with fewer isolation layers. However, coupled inductor circuits are prone to leakage voltage spike, which somewhat impairs the zero voltage switching condition of the power switch.

[00200] To further improve the efficiency, albeit at increased complexity and cost, each power conversion circuit may include a synchronous rectifiers (SR) as illustrated in Figure 42. Since L_r's current peak and, accordingly, the current discharge time strongly depend on input voltage, application of adaptive or predictive SR control circuits is required. SR's drive circuits can be conveniently fed by the output voltage.

[00201] Any combination of any circuits and/or of any component illustrated in any one of the mentioned above figures can be provided. Any combination of any subject matter included in any claim can be provided.

[00202] Any reference to any of the terms "comprise", "comprises", "comprising" "including", "may include" and "includes" may be applied to any of the terms "consists", "consisting", "consisting essentially of. For example - any of the circuits illustrated in any figure may include more components that those illustrated in the figures, only the components illustrated in the figures or substantially only the components illustrated in the figures.

[00203] In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention as set forth in the appended claims.

[00204] Moreover, the terms "front, " "back, " "top, " "bottom, " "over, " "under " and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. [00205] Those skilled in the art will recognize that the boundaries between logic blocks are merely illustrative and that alternative embodiments may merge logic blocks or circuit elements or impose an alternate decomposition of functionality upon various logic blocks or circuit elements. Thus, it is to be understood that the architectures depicted herein are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality.

[00206] Any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as

"associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected, " or "operably coupled, " to each other to achieve the desired functionality.

[00207] Furthermore, those skilled in the art will recognize that boundaries between the above described operations merely illustrative. The multiple operations may be combined into a single operation, a single operation may be distributed in additional operations and operations may be executed at least partially overlapping in time.

Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be altered in various other embodiments.

[00208] Also for example, in one embodiment, the illustrated examples may be implemented as circuitry located on a single integrated circuit or within a same device. Alternatively, the examples may be implemented as any number of separate integrated circuits or separate devices interconnected with each other in a suitable manner.

[00209] However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

[00210] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the terms "a " or "an, " as used herein, are defined as one or more than one. Also, the use of introductory phrases such as "at least one " and "one or more " in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a " or "an " limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more " or "at least one " and indefinite articles such as "a " or "an. " The same holds true for the use of definite articles. Unless stated otherwise, terms such as "first" and "second" are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements.

[00211] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

WE CLAIM 1. A power conversion circuit, comprising:

first and second input ports that are configured to receive an alternating input signal;

first and second output ports that are configured to provide an output signal to a group of light emitting diodes; wherein the group of light emitting diodes comprises at least one light emitting diode;

at least one inductor, a switching unit , multiple capacitors and a rectifier for rectifying the alternating input signal;

wherein the at least one inductor, the switching unit , the rectifier and the multiple capacitors are coupled between (a) the first and second input ports and (b) the first and second output ports;

wherein the multiple capacitors comprises a set of isolating capacitors that comprise a first isolating capacitor and a second isolating capacitor; and

wherein the set of isolating capacitors is configured to:

(a) provide a capacitive isolation barrier between the first input port and the first output port and between the second input port and the second output port; and

(b) participate in a resonant or quasi-resonant power conversion across the capacitive isolation barrier.

2. The power conversion circuit according to claim 1 wherein the resonant or quasi- resonant power conversion across the capacitive isolation barrier is a part of a conversion of the alternating input signal to the output signal.

3. The power conversion circuit according to claim 1 wherein the power conversion circuit does not include a transformer.

4. The power conversion circuit according to claim 1 wherein the power conversion circuit does not include an electrolytic capacitor.

5. The power conversion circuit according to claim 1 wherein the rectifier is a bridge rectifier.

6. The power conversion circuit according to claim 1 wherein the rectifier is a bridgeless rectifier.

7. The power conversion circuit according to claim 1 wherein the switching unit includes only a single switch.

8. The power conversion circuit according to claim 1 wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement.

9. The power conversion circuit according to claim 1 wherein the switching unit is configured to perform a zero current turn on switching.

10. The power conversion circuit according to claim 1 wherein the switching unit is configured to perform a zero voltage turn on switching.

11. The power conversion circuit according to claim 1 wherein the switching unit is configured to perform a zero current turn off switching.

12. The power conversion circuit according to claim 1 wherein the switching unit is configured to perform a zero voltage turn off switching.

13. The power conversion circuit according to claim 1 wherein the set of isolating capacitors virtually partitions the power conversion circuit to an input portion and an output portion.

14. The power conversion circuit according to claim 13 wherein the at least one inductor includes only a single output inductor that belongs to the input portion.

15. The power conversion circuit according to claim 13 wherein the at least one inductor includes only a single output inductor that belongs to the input portion and only a single output inductor that belongs to the output portion.

16. The power conversion circuit according to claim 13 wherein the at least one inductor includes only a single output inductor that belongs to the input portion and a plurality of output inductors that belongs to the output portion.

17. The power conversion circuit according to claim 1 further comprising at least one diode for controlling a direction of energy flow during the resonant or quasi resonant power conversion across the capacitive isolation barrier.

18. The power conversion circuit according to claim 1 further comprising an output diode; wherein the at least one inductors comprises an input inductor and an output inductor;

wherein the multiple capacitors comprises an input capacitor and the set of isolating capacitors;

wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output;

wherein the switching unit is a single switch;

wherein a first end of the input inductor is coupled to the first rectifier output and to a first end of the input capacitor;

wherein a second end of the input inductor is coupled to the a first end of the first isolating capacitor and to a first port of the single switch;

wherein a second end of the first isolating capacitor is coupled to an anode of the output diode and to a first end of the output inductor;

wherein a second end of the output inductor is coupled to the first output port; wherein a cathode of the output diode is coupled to the second output port and to a second end of the second isolating capacitor;

wherein a first end of the second isolating capacitor is coupled to a second end of the single switch, to a second end of the input capacitor and to the second rectifier output.

19. The power conversion circuit according to claim 18 further comprising a controller for controlling the single switch.

20. The power conversion circuit according to claim 19 wherein the controller comprises:

a sensor for detecting a valley in a voltage of the first port of the single switch and for generating a valley detection signal; and

a detector for controlling the single switch in response to the valley detection signal and in response to a clock signal.

21. The power conversion circuit according to claim 20 wherein the detector comprises at least a single bipolar transistor.

22. The power conversion circuit according to claim 18 wherein the single switch is configured to be closed during a first portion of each resonant cycle of the quasi-resonant power conversion.

23. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor and an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a single switch; wherein the power conversion circuit comprises an input diode, a first output diode and a second output diode; wherein an anode of the input diode is coupled to the first rectifier output and to a first end of the input capacitor; wherein a cathode of the input diode is coupled to a first end of the input inductor; wherein a second end of the input inductor is coupled to the a first end of the first isolating capacitor and to a first port of the single switch;

wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode and to a cathode of the second output diode; wherein an anode of the second output diode is coupled to a first end of the output inductor; wherein a cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port; wherein a second end of the output capacitor is coupled to the second output port, to a second end of the output inductor and to a second end of the second isolating capacitor; wherein a first end of the second isolating capacitor is coupled to a second end of the single switch, to a second end of the input capacitor and to the second rectifier output.

24. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor and an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a single switch; wherein the power conversion circuit comprises an input diode and an output diode; wherein an anode of the input diode is coupled to the first rectifier output and to a first end of the input capacitor; wherein a cathode of the input diode is coupled to a first end of the input inductor; wherein a second end of the input inductor is coupled to the a first end of the first isolating capacitor and to a first port of the single switch; wherein a second end of the first isolating capacitor is coupled to a first end of the output inductor and to an anode of the output diode; wherein a cathode of the output diode is coupled to a first end of the output capacitor and to the first output port; wherein a second end of the output capacitor is coupled to the first output port , to a second end of the output inductor and to a second end of the second isolating capacitor; wherein a first end of the second isolating capacitor is coupled to a second end of the single switch, to a second end of the input capacitor and to the second rectifier output.

25. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor and an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridgeless rectifier and comprises a first input diode and a second input diode; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises a first output diode and a second output diode; wherein a first end of the input inductor is coupled to the first input port; wherein a second end of the input inductor is coupled to an anode of the first input diode and to a cathode of the second input diode; wherein a cathode of the first input diode is coupled to a first output port of the switching unit and to a first end of the first isolating capacitor; wherein an anode of the second input diode is coupled to a second port of the switching unit and to a first end of the second isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode and to a cathode of the second output diode; wherein an anode of the second output diode is coupled to a first end of the output inductor; wherein a cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port; wherein a junction between the pair of switches is coupled to the second input port; and wherein a second end of the output capacitor is coupled to the second output port, to a second end of the output inductor and to a second end of the second isolating capacitor.

26. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor and an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridgeless rectifier and comprises a first input diode and a second input diode; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises an output diode; wherein a first end of the input inductor is coupled to the first input port; wherein a second end of the input inductor is coupled to an anode of the first input diode and to a cathode of the second input diode; wherein a cathode of the first input diode is coupled to a first output port of the switching unit and to a first end of the first isolating capacitor; wherein an anode of the second input diode is coupled to a second port of the switching unit and to a first end of the second isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the output diode and to a first end of the output inductor; wherein a cathode of the output diode is coupled to a first end of the output capacitor and to the first output port; wherein a junction between the pair of switches is coupled to the second input port; and wherein a second end of the output capacitor is coupled to the second output port, to a second end of the output inductor and to a second end of the second isolating capacitor.

27. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor, an output inductor and an additional output inductor; wherein the multiple capacitors comprises an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridgeless rectifier and comprises a first input diode and a second input diode; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises a first output diode and a second output diode; wherein a first end of the input inductor is coupled to the first input port; wherein a second end of the input inductor is coupled to an anode of the first input diode and to a cathode of the second input diode; wherein a cathode of the first input diode is coupled to a first output port of the switching unit and to a first end of the first isolating capacitor; wherein an anode of the second input diode is coupled to a second port of the switching unit and to a first end of the second isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode and to a first end of the additional output inductor; wherein a cathode of the first output diode is coupled to a first end of the output inductor, to the second output port and to a first end of the output capacitor; wherein a second end of the output inductor is coupled to a second end of the second isolating capacitor and to a cathode of the second output diode; wherein a second end of the additional output inductor is coupled to an anode of the second output diode, to the second output port and to a second end of the output capacitor; wherein a junction between the pair of switches is coupled to the second input port.

28. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor, an output inductor and an additional output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier and comprises a first rectifier output and a second rectifier output; wherein the switching unit comprises a single switch; wherein the power conversion circuit further comprises a first input diode, a first output diode and a second output diode; wherein an anode of the input diode is coupled to the first rectifier output and to a first end of the input capacitor;

wherein a cathode of the input diode is coupled to a first end of the input inductor;

wherein a second end of the input inductor is coupled to the a first end of the first isolating capacitor and to a first port of the single switch; wherein a second end of the first isolating capacitor is coupled to an anode of the second output diode and to a first end of the output inductor; wherein a cathode of the second output diode is coupled to a first end of the additional output inductor, to the second output port and to a first end of the output capacitor; wherein a second end of the additional output inductor is coupled to a second end of the second isolating capacitor and to a cathode of the first output diode; wherein a second end of the output inductor is coupled to an anode of the first output diode, to the first output port and to a first end of the output capacitor.

29. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier and comprises a first rectifier output and a second rectifier output; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises a first output diode and a second output diode; wherein a first end of the input capacitor is coupled to the first rectifier output, to a first port of the switching unit and to a first end of the first isolating capacitor; wherein a second end of the input capacitor is coupled to the second input port and to a second port of the switching unit; wherein a second end of first isolating capacitor is coupled to a first end of the output inductor; wherein a second end of the output inductor is coupled to an anode of the first output diode and to a cathode of the second output diode; wherein a cathode of the first output diode is coupled to a first end of the output capacitor and to the first output port; wherein the second output port is coupled to a second end of the output capacitor, to an anode of the second output diode and to a second end of the second isolating capacitor; wherein a first end of the second isolating capacitor is coupled to a junction between the pair of switches.

30. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an output inductor; wherein the rectifier is an input rectifier; wherein the power conversion circuit further comprises an output bridge rectifier; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the input rectifier is a bridge rectifier; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein a first end of the input capacitor is coupled to a first output port of the input rectifier, to a first port of the switching unit and to a first end of the first isolating capacitor; wherein a second end of the input capacitor is coupled to a second output port of the input rectifier and to a second output port of the switching unit; wherein a second end of first isolating capacitor is coupled to a first end of the output inductor; wherein a second end of the output inductor is coupled to a first input port of the output rectifier; wherein a first end of the output capacitor is coupled to the first output port of the power conversion circuit and to a first output port of the output rectifier; wherein a second end of the output capacitor is coupled to the second output port of the power conversion circuit and to a second output port of the output rectifier; wherein a second end of the second isolating capacitor is coupled to a second input port of the output rectifier; and wherein a first end of the second isolating capacitor is coupled to a junction between the pair of switches.

31. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor and an output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises a first output diode and a first input diode; wherein a first end of the input capacitor is coupled to a first output port of the rectifier and to an anode of the input capacitor; wherein a cathode of the input diode is coupled to a first end of the input inductor; wherein a second end of the input inductor is coupled to a first port of the switching unit; wherein a junction between the pair of switches is coupled to a first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the output diode and to a first end of the output inductor; wherein a second end of the output inductor is coupled to the first output port and to a first end of the output capacitor; wherein a second end of the output capacitor is coupled to the second output port, to a cathode of the output diode and to a second end of the second isolating capacitor; and wherein a first end of the second isolating capacitor is coupled to a second port of the switching unit .

32. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an input inductor, an output inductor and an additional output inductor; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit further comprises a first output diode, a second output diode and a first input diode; wherein a first end of the input capacitor is coupled to a first output port of the rectifier and to an anode of the input capacitor;

wherein a second end of the input inductor is coupled to a first port of the switching unit; wherein a junction between the pair of switches is coupled to a first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode and to a first end of the additional output inductor; wherein a second end of the additional output inductor is coupled to the first output port, to a first end of the output capacitor and to an anode of the output capacitor; wherein a second end of the output capacitor is coupled to the second output port, to a cathode of the first output diode and to a first end of the output inductor; wherein a cathode of the second output diode is coupled to a second end of the additional output inductor and to a second end of the second isolating capacitor; wherein a first end of the second isolating capacitor is coupled to a second port of the switching unit .

33. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an output inductor; wherein the rectifier is an input rectifier; wherein the power conversion circuit further comprises an output rectifier that is a bridge rectifier; wherein the multiple capacitors comprises an input capacitor, an output capacitor and the set of isolating capacitors; wherein the input rectifier is a bridge rectifier; wherein the switching unit comprises a pair of switches that are arranged in a totem pole arrangement; wherein a first end of the input capacitor is coupled to a first output port of the input rectifier; wherein a second end of the input capacitor is coupled to a second output port of the input rectifier and to a second output port of the switching unit; wherein a second end of first isolating capacitor is coupled to a first input port of the output rectifier; wherein a first end of the output inductor is coupled to the first output port of the output rectifier; wherein a second end of the output inductor is coupled to a first end of the output capacitor and to the first output port of the power conversion circuit; wherein a second end of the output capacitor is coupled to a second output port of the output rectifier;

wherein a second input port of the output rectifier is coupled to a second end of the second isolating capacitor; and wherein a first end of the second isolating capacitor is coupled to a second port of the switching unit .

34. The power conversion circuit according to claim 1 wherein the at least one inductors comprises an output inductor and an additional output inductor; wherein the multiple capacitors comprises an input capacitor, a first output capacitor, a second output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises a first output diode and a second output diode; wherein a first end of the input capacitor is coupled to the first rectifier output and to a first port of the switching unit; wherein a second end of the input capacitor is coupled to the second rectifier output and to a second port of the switching unit; wherein a junction that is coupled between the pairs of switches is coupled to a first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the output inductor; wherein a cathode of the first output capacitor is coupled to a first end of a first output capacitor and to the first output port; wherein a second end of the first output capacitor is coupled to a second end of the output inductor, to a first end of the second output capacitor and to a first end of the additional output inductor; wherein a second end of the second output capacitor is coupled to the second output port and to an anode of the second output diode; wherein a first end of the additional output inductor is coupled to a second end of the second isolating capacitor; and wherein a first end of the second isolating capacitor is coupled to a second port of the switching unit and to the second output port of the rectifier.

35. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor, a second input inductor and a third input inductor; wherein the multiple capacitors comprises a first input capacitor, a second input capacitor, a third input capacitor, a first output capacitor, a second output capacitor, a third output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement;

wherein the power conversion circuit comprises a first input diode, a second input diode, a third input diode, a first output diode, a second output diode and a third output diode; wherein a first end of the first input capacitor is coupled to the first rectifier output and to an anode of the first input diode; wherein a second end of the first input capacitor is coupled to a first end of the second capacitor, to a junction between the pair of switches and to a first end of the second input inductor; wherein a second end of the second input capacitor is coupled to the second rectifier output and to a cathode of the second input diode; wherein a cathode of the first input diode is coupled to a first end of the first input inductor; wherein a second end of the first input inductor is coupled to a first port of the switching unit and to a first port of a third input diode; wherein an anode of the second input diode is coupled to a first end of the third input inductor; wherein a second end of the third input inductor is coupled to a second port of the switching unit , to a second end of the third input capacitor and to a second end of the second isolating capacitor; wherein a second end of the second input inductor is coupled to a first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor; wherein a cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; wherein a cathode of the third output diode is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the third output capacitor.

36. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor; wherein the multiple capacitors comprises a first input capacitor, a second input capacitor, a first output capacitor, a second output capacitor, a third output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises, a first output diode, a second output diode and a third output diode; wherein a first end of the first input capacitor is coupled to the first rectifier output and to a first port of the switching unit; wherein a second end of the first input capacitor is coupled to a first end of the second capacitor and to a first end of a third input capacitor; wherein a junction between the pair of switches is coupled to a first end of the first input inductor; wherein a second end of the switching unit is coupled to the second rectifier output and to a second end of the second input capacitor; wherein a second end of the first input inductor is coupled to a first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor; wherein a cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; wherein a cathode of the third output diode is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the third output capacitor.

37. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor, a first output inductor and a second output inductor; wherein the multiple capacitors comprises a first input capacitor, a second input capacitor, a first output capacitor, a second output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises, a first output diode and a second output diode; wherein a first end of the first input capacitor is coupled to the first rectifier output and to a first port of the switching unit; wherein a second end of the first input capacitor is coupled to a first end of the second capacitor and to a first end of the second isolating capacitor; wherein a junction between the pair of switches is coupled to a first end of the first isolating capacitor; wherein a second end of the switching unit is coupled to the second rectifier output and to a second end of the second input capacitor; wherein a second end of the second isolating capacitor is coupled to a first end of the first output inductor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the second output inductor; wherein a cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; wherein a second end of the second output inductor is coupled to a second end of the first output capacitor, to a first end of the second output capacitor and to a second end of the first output inductor.

38. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor; wherein the multiple capacitors comprises a first input capacitor, a second input capacitor; a first output capacitor, a second output capacitor, a third output capacitor and the set of isolating capacitors; wherein the set of isolating capacitors further comprise a third isolating capacitor; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output;

wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises a first input diode, a second input diode, a first output diode, a second output diode and a third output diode; wherein a first end of the first input capacitor is coupled to the first rectifier output and to an anode of the first input diode; wherein a second end of the first input capacitor is coupled to a first end of the second isolating capacitor, to a second end of the third isolating capacitor, to a second port of the switching unit and to second end of the second input capacitor; wherein an anode of the second input diode is coupled to a cathode of first input diode and to a first end of the second isolating capacitor; wherein a cathode of the second input diode is coupled to a first port of the switching unit and to a first end of the second input capacitor; wherein a second end of the third isolating capacitor is coupled to a first end of the third isolating capacitor, to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor;

wherein a cathode of the first output diode is coupled to a first end of a first output capacitor; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; and wherein a second end of the third output capacitor is coupled to the first end of the first isolating capacitor, to the first output port and to a second end of the first output capacitor.

39. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor and a second input inductor; wherein the multiple capacitors comprises a first input capacitor, a first output capacitor, a second output capacitor, a third output capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises a first input diode, a second input diode, a third input diode, a first output diode and a second output diode; wherein a first end of the first input inductor is coupled to the first rectifier output and to an anode of the first input diode; wherein a cathode of the first input diode is coupled to a first end of the first input capacitor and to a first port of the switching unit; wherein a second port of the switching unit is coupled to a second end of the first input capacitor, to an anode of the third input diode and to a first end of the second isolating capacitor; wherein an anode of the second input diode is coupled to a first switch of the pairs of switches, to a cathode of the third input diode and to a first end of the second input inductor; wherein a cathode of the second input diode is coupled to a second switch of the pairs of switches and to the second rectifier output; wherein a second end of the second input inductor is coupled to the first end of the first isolating capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the third output capacitor; wherein a cathode of the first output diode is coupled to a first end of a first output capacitor; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; and wherein a second end of the third output capacitor is coupled to the first end of the second isolating capacitor, to the first output port and to a second end of the first output capacitor.

40. The power conversion circuit according to claim 1 wherein the at least one inductors comprises a first input inductor, a first output inductor and a second output inductor; wherein the multiple capacitors comprise a first input capacitor and the set of isolating capacitors; wherein the rectifier is a bridge rectifier that comprises a first rectifier output and a second rectifier output; wherein the switching unit is a pair of switches that are arranged in a totem pole arrangement; wherein the power conversion circuit comprises a first input diode, a second input diode, a third input diode, a first output diode and a second output diode; wherein a first end of the first input inductor is coupled to the second rectifier output and to an anode of the first input diode; wherein a cathode of the first input diode is coupled to a first end of the first input capacitor and to a first port of the switching unit; wherein a second port of the first input inductor is coupled to a second port of the switching unit , to a second end of the first input capacitor, to an anode of the third input diode and to a first end of the second isolating capacitor; wherein an anode of the third input diode, a cathode of the second input diode and a first switch of the pair of switches are coupled to a first port of the first isolating capacitor; wherein a second end of the second isolating capacitor is coupled to a first end of a second output capacitor; wherein a second end of the first isolating capacitor is coupled to an anode of the first output diode, to a cathode of the second output diode and to a first end of the first output inductor; wherein a cathode of the first output diode is coupled to a first end of a first output capacitor and to the first output port; wherein an anode of the second output diode is coupled to a second end of the second output capacitor and to the second output port; wherein a second end of the first output inductor is coupled to the second end of the second output inductor, to a second end of the first output capacitor and to a first end of the second output capacitor; and wherein a cathode of the second input diode is coupled to the first rectifier output and to a second switch of the pair of switches.

41. The power conversion circuit according to any claim of claims 23-28 wherein the switching unit is configured to perform a zero voltage turn off switching and a zero current turn on switching.

42. The power conversion circuit according to any claim of claims 29-33 wherein the switching unit is configured to perform a zero current turn off switching and a zero current turn on switching.

43. The power conversion circuit according to any claim of claims 34-40 wherein the switching unit is configured to perform a zero voltage turn off switching and a zero voltage turn on switching.

44. The power conversion circuit according to any claim of claims 23-33 wherein the power conversion circuit is configured to perform the quasi-resonant power conversion.

45. The power conversion circuit according to any claim of claims 34-40 wherein the power conversion circuit is configured to perform the resonant power conversion.