TW200919921A - Synchronous self-driven power converter - Google Patents

Abstract

The present invention relates to a synchronous self-driven power converter for converting a dc input voltage (Vin) to a dc output voltage (VO) and/or a dc output current (iO) for supplying a load (LO), comprising: a chopper unit (S) for chopping said dc input voltage (Vin) into an ac intermediate voltage (VD), a rectifier unit for rectifying said ac intermediate voltage and for outputting said rectified output voltage to said load, said rectifier unit comprising a bipolar transistor (T; T4) as the rectifying element, whose base is coupled to a control current supply terminal for providing a control current to the base of said bipolar transistor for converting said bipolar transistor into a conductive state, when said chopper unit is in its OFF state.

Description

200919921 IX. Description of the Invention: [Technical Field] The present invention relates to a synchronous self-driving power converter for converting a DC input voltage to a DC output voltage or a DC output current to supply a load.

The invention further relates to a driver for providing a DC drive voltage to a load, in particular to an LED unit, a backlight Cuiyuan, an LED unit or a rear combination lamp unit; and the invention relates to an operation A method of synchronizing a self-driving power converter, the converter for converting a DC input voltage to a DC output voltage or a continuous current output to supply a load. [Prior Art] The present invention is generally directed to a very simple and cost effective driver for use in, for example, (O) LED modules. The cost of the electronic driver for the (0) LED module is a key factor in many applications (LCD backlighting, automotive, conventional lighting, etc.). A typical low-cost driver topology is the so-called self-oscillating buck converter (SOPS), which is described, for example, in August 27-28, 2001, Austrian Graz <EPE-2001S 9th European Conference on Power Electronics and Applications> M. Ossmann " Simple cheap converters f0r the Classr00m". One of the reasons why the converter is still used at a low cost is its 7〇%_75% limited efficiency. Synchronizing the entire Λ1 is a common method for improving the efficiency of many converter topologies with low output voltages. Here, the switch is used to replace the rectifier diode in the output stage, which reduces the voltage drop across the rectifier 131652.doc 200919921 from a typical 700 mV-1000 mV to 1 〇〇 mV or more (and So 'reduce the loss'. Renhao MOSFETs are difficult to apply to low output voltage sops compared to other competitors because of their high gate voltage requirements of 5 ν_ι〇 v. Another problem can be caused by the M〇SFET intrinsic body diode. WQ G1/6G167 A2 discloses a flashlight that includes a switch mode conversion thief for converting an energy reserve to a fixed voltage to supply a bulb to maintain a constant brightness over the useful life of the energy reserve. Typically, the 7-turn transistor is an M〇SFET. However, if desired, a bipolar transistor can be used along with an external anti-parallel diode. These synchronous switches are driven by a controller' which adds considerable complexity and cost to the circuit. SUMMARY OF THE INVENTION The present invention is directed to providing a synchronous self-driving power converter that converts a DC input voltage to a DC output voltage or a DC output current to supply a load; and provides an operation for the synchronization. A corresponding method of self-driving V power converters.

In the first aspect of this & month, a synchronous self-driving power conversion cry includes: , D chopper unit 'which is used to draw the DC input voltage to an AC intermediate voltage; - — * ί - "π, which is used to rectify the AC intermediate voltage and output the power outhouse to the load, the rectifier unit includes a bipolar transistor: 曰 ''H piece' when the chopper unit is off The base of the bipolar electrode body is coupled to a control current supply terminal, and the control current I31652.doc 200919921 supply terminal is used to provide a control current to the base to convert the bipolar transistor to a conduction. status. In the present invention, a method for operating a synchronous self-driving power conversion benefit comprises the following steps: • - extracting the DC input voltage to an alternating current intermediate voltage; _ - #1 by - rectifier unit Rectifying the alternating current intermediate voltage, the rectifier unit includes a bipolar transistor; f '· _ outputting the rectified output voltage to the load; - turning on and off the turn-off voltage to the rectifier unit, and - when When the chopper unit is in the off state, a control current is supplied to the base of the bipolar transistor to convert the bipolar f crystal to a conducting state. In one aspect of the invention, a driver is used to provide a chest voltage and/or a DC drive current to the load, particularly to a 7 LED unit, a backlight unit, a -lcd unit or a post-combination. The lamp unit includes a synchronous self-driving power conversion u as required to convert the DC input voltage to the DC drive voltage and/or the DC drive current. The preferred embodiment of the invention is defined by the associated claim. We will appreciate that the method and the driver have similar and/or identical preferred embodiments as the synchronous self-driven power converter, and are defined by the dependent request item of claim 1. The present invention is based on the concept of a rectifier diode instead of a DC to DC converter (e.g., a buck converter) with a synchronous switch. Unlike the commonly used MOSFET's - bipolar transistors are used to replace (or in parallel) the standard full 131652.doc 200919921 flow diode diode, making the circuit ideally suited to the traditional best price-performance ratio self-oscillating power supply (S0PS). The solution provides step-by-step _ low cost and high efficiency for simultaneous rectification in low output (IV) applications. The use of MOSFETs in these applications is more difficult due to extra drive operation. The chopper unit (which can be a single transistor 屯曰 肢 -- - 丁 驭 驭 驭 ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) Preferably, the chopper unit acts as a switching unit for turning the input voltage to the coupling of the rectifier unit. The synchronous power converter proposed by the present invention is self-driven and does not require any controller as compared to the circuit shown by W〇〇:/6〇127A2*. The circuit is operated to automatically set the on and off states. This reduces circuit cost and complexity and achieves the same benefits/functions as circuits with a dedicated controller. Preferably, the chopper unit advances the output (4) with respect to the rectifier unit, ie, the coupling voltage of the output voltage to the rectifier unit (" is enabled by the chopper unit / Undo enable (direct or indirect ^ here 'words " face is enabled " is about the state of the synchronous rectifier = conduction = (= open) the state 'predicate, the union is revoked, the system is about the same two: thieves It is a state of non-conduction state (, break). By using the correct circuit eigensignal that already exists in the ^, the appropriate (4) _ can be obtained. :: The method can significantly improve the driving of the standard self-oscillating buck converter. Even without increasing (or even reducing) the total driver cost. This is especially useful for applications that require low-power (〇) LED drivers, such as I31652.doc 200919921 for LCD TVs (1) or offenses. Segmented back force; also attractive for highly cost-driven applications such as automotive drives for rear combination lamps RCL. The present invention thus provides a synchronous rectification in almost any type of DC to DC converter. Very cheap and high The method of efficiency (and therefore, efficient power conversion). According to a preferred embodiment, the rectifier unit further comprises one or more reactive components coupled to the chopper unit, the bipolar transistor, and the load: 'In particular, one or more capacitors, inductive components and/or transformers. For example, an inductive component (eg, a simple inductor) is provided that is coupled in series to the bipolar transistor and the load. The component is used as an energy storage component that is charged when the input voltage is applied to the rectifier unit, and is discharged when the input voltage is turned off to the rectifier unit. According to the embodiment, an impedance unit is provided, a terminal is coupled to the base of the bipolar transistor to provide the control current. The additional impedance (eg, a simple resistor) connects the base of the bipolar transistor to a voltage potential to cause the bipolar transistor to If necessary, take over the freewheeling current of the standard rectifier diode. Preferably, the other terminal of the impedance unit is coupled to the output voltage. For example, 'the reactive element is an electric In the case of an element, the other terminal of the impedance unit is coupled to the terminal of the inductive element that is not surfaced to the bipolar transistor. Thus 'when the output voltage is decoupled from the rectifier unit, the inductance When the component is discharged, the residual component provides a control current for switching the bipolar transistor to a conducting state. 131652.doc -10. 200919921 The control current is advantageously derived from the direct current. The DC voltage is selected for the DC voltage. Whether it is in the circuit which causes the minimum rectifier loss. Which of the output voltage or the direct current reference voltage depends on: First, it can be taken; secondly, in the embodiment, the voltage is in the embodiment Ren Jiezao 70 further includes a rectifier diode 'coupled between the κ < emitter and collector of the bipolar transistor. In this embodiment, the diode is used to increase the output voltage to its adjusted value.

In the case of the case (for example, during circuit startup) voltage rectification is also guaranteed. In another embodiment, the reactive component is a transformer for transforming the input voltage to an intermediate voltage, and the chopper unit is coupled between the primary winding of the transformer and an input voltage supply unit. This embodiment is typically used in converters that require galvanic isolation between the output voltage and the input voltage, or transformers (4) to regulate the particular current voltage to minimize losses and/or cost. Further, the rectifier unit preferably comprises a pair of bipolar transistors, wherein the impedance unit comprises two impedance elements, and the terminals of the S components that are not consuming to the base of the associated bipolar transistor are combined with each other. And in the middle of one of the separated secondary windings of the transformer, ask her; This practical example is commonly used in a resonant converter using full-wave rectification. The invention is particularly useful for applications requiring multiple drivers (e.g., for 2D backlighting of L(3) televisions) or for highly cost sensitive applications (e.g., combined lamps or RCLs for automotive applications). The invention is also applicable to pwM or AM withering circuits and a variety of converter topologies, providing good integration possibilities and resulting in a highly competitive driver concept. 13I652.doc 200919921 [Embodiment] Hereinafter, by explaining an embodiment and performance of synchronous rectification with a bipolar transistor for a self-oscillating buck converter, the present invention will be illustrated. FIG. 1 illustrates standard self-oscillation. Buck converters, for example, such as August 27-28 S ^^iljGraz <EPE, 2〇〇1j 9th Eur〇pean c〇nference

II Power Electronics and AppUcati〇ns> m 〇崎瞻 ’’Srniple cheap converters f〇r the saga (10)" The converter is adapted to convert a DC input voltage Vin supplied from a voltage source VSm to a DC output voltage v〇 or a DC output current 丨〇 to supply a load L0 (in this example, a led). The converter comprises two transistors T1 and T3 which, together with the resistor Han 2, form a current limiting switch in which the main current flows through the cesium. When 71 is closed = (on state), the input voltage Vin is subtracted from the voltage drop Vr2 across the shunt resistor R2 (the VR2 is small compared to Vin) is applied to the cathode of the diode ,, and is performed. The bias voltage is reversed so that current does not flow through the rectifier diode D. In steady state operation, the voltage drop across the inductor in this case is about Vin_v. This causes the inductor current iL to rise linearly. When a certain peak current is reached (defined by the quotient of the emitter base threshold voltage of about 700 mV and the resistor R2), the transistor T3 begins to conduct, taking over the current flowing through the base of the butadiene. At this time, the current passing through the inductor L no longer continues to flow through T1, but is forced to flow through the diode D. This causes the cathode voltage of D to change from Vin to ground, and thus turns off the base current of transistor T2 and thus also the current flowing through transistor T3. The voltage drop across inductor L is now _v. Therefore, the inductor current iL is linearly decremented to zero. At this time, the transistor D2 is turned on again by the (starting) power 131652.doc -12· 200919921, and the entire cycle starts again. It is worth noting that the value set by the resistors is the ideal average current of the LED LO. Capacitor C is selected and can be used to reduce the current in the recharge current 1 crystal T2 :3. Therefore, the current limit switch is also referred to herein as a chopper, which is used directly: the body voltage. "Intermediate voltage vD (also known as the layout and function of such a buck converter) The technology is known, so it will not be described again. In Figure 2 and Figure 3, respectively, the electricity through the inductor "and the voltage across the diode vD and the diode body, *; # # • (4) electricity * lD ° In particular, FIG. 2 shows the inductor "and the diode voltage nine", and FIG. 3 shows the diode current and the diode voltage VD. In FIG. 4, it can be seen that the voltage is 3 v LED The instantaneous diode loss of the input voltage of V, l〇V. It can be seen from the figure that the loss of one pole D can significantly reduce the efficiency of the converter. An embodiment of the proposed new circuit of an oscillating buck converter. In addition to the circuit shown in Figure 1, the new circuit also includes a bipolar transistor T4 for synchronous rectification, the base of which is via a The base impedance Ζ is connected to the LED string voltage (the voltage at the terminal connecting the inductor L and the load L )), that is, the first end of the impedance Z Z1 is coupled to the base of the bipolar transistor D4 and its second terminal T2 is coupled to the positive terminal of the LED string voltage ν〇. When the "switch" is turned off, it is used to convert the bipolar transistor D to The control current of the on state is supplied to the base of the "Thai Bipolar" a T2 via the impedance (for example, a simple resistor in this embodiment). The crystal has a current gain, is inexpensive, implements fast switching and provides a low threshold voltage of about 1 〇〇 mV (depending on the type of bipolar transistor used, eg 5 〇 mV). Further, it has a specific MOSFET ( It has a 5-10 V high gate phantom or a standard rectifier diode (Si diode) (which has 7 〇〇 mV _ 〇〇〇 ^ ^ forward electrical calendar drop) much lower bias voltage (for example, 〇7 V base emitter voltage

Vbe). 'In particular, when the "switch" is turned on, the voltage at the emitter of the bipolar transistor T (equal to the alternating intermediate voltage Vd) corresponds to the input voltage, and the base shot of the bipolar electric solar body T4 The pole voltage Vbe is negative. When the " switch π is off and the intermediate voltage VD is zero (or near zero), the voltage at the emitter of the bipolar transistor becomes zero and the base emitter voltage Vbe becomes greater than zero to The epipolar transistor is turned on. As a result, the bipolar transistor T4 takes over L, otherwise iL will flow through D, thereby significantly reducing rectifier losses. Thus, the synchronous "switch" of the circuit in accordance with the present invention is self-driven. Typical values for the components of the converter embodiment of Figure 5 are: L: typically 10 μΗ to 50 mH; Z(R): typically 1〇〇〇 to 1〇〇; c· select 'L: typical 10nF to 1〇 〇〇μρ; R1: typically 1 ΙίΩ to 1000 kQ; R3: typically 100 Ω to 500 kQ; R2: typically 1 γ ώ Ω to 1000 Ω; obviously these values are only examples that can be used in a preferred embodiment. However, the invention is in no way limited to the use of such equivalents. Other values are of course also desirable 131652.doc 14 200919921. FIG. 6 illustrates the collector current 丨c and the diode voltage VD of the bipolar transistor τ 4 . It can be seen that 'using synchronous rectification can significantly reduce the diode forward voltage' and thus significantly reduce rectification losses, thereby increasing converter efficiency. The following figures illustrate a further embodiment of the present invention showing how synchronous rectification with one or more bipolar transistors can be achieved in all major DC to DC converter topologies. In these figures, the bipolar transistor is indicated by D or by Ta, Tb, respectively, by means of a switch. Figure 7 depicts an embodiment of a synchronous rectification of a bipolar transistor without a standard buck converter. The rectifier function (which is usually implemented by an expensive diode, the diode generates a lot of forward losses, and also produces a lot of reverse losses at higher temperatures) is now replaced by a transistor T, which does not have the above And so on. During the freewheeling time, the cathode of the diode D has a negative voltage potential, and the potential of the voltage V〇 is higher than the cathode potential of the diode D. This means that the impedance Z supplies the base current of the transistor T, and the transistor is turned on to perform the rectifying function. The diode D can be a very inexpensive diode, since the function now only initiates rectification. When the rectifying system is fully active, the diode D will be bypassed by the collector emitter saturation voltage of the transistor τ. In the absence of the diode D, the circuit will also operate because the polarity of the impedance L voltage V1 is actually interchanged during the rectification time so that the voltage potential of the voltage v〇 is always at the emitter of the transistor T. Voltage potential. The transistor 1 can be any type of transistor, such as a bipolar transistor or FET. Figure 8 does not have a synchronous rectification embodiment of a bipolar transistor in a standard boost converter. FIG. 9 illustrates a synchronous rectification embodiment of a bipolar daytime 131652.doc 15 200919921 body τ with a standard buck boost converter. The figure shows a synchronous rectification (half-wave rectification) embodiment of a bipolar transistor T in a standard down converter (which uses a transformer Tr having a primary winding prim and a primary winding sec). Figure 2 shows the synchronous rectification of the bipolar transistors Ta, Tb in the standard resonant converter (full-wave rectification of the separated secondary windings sec_a, sec_b of the variable Tr; Tr; The main stage side of the device) embodiment. Figure 12 illustrates a further embodiment of a transistor synchronous rectifier in accordance with the present invention, particularly a buck converter circuit for use in automotive RCL applications with the same additional transistor synchronous rectifier. When the peak current value is reached (which can be adjusted by R11), transistor Q16 will be turned off and the input V- of operational amplifier U11D will be lower than input V+, and thus the output of the operational amplifier UUD will be boosted. As a result, the transistor Q17 is turned on. The rectification cycle section has now started. This will continue until the current is reduced by the impedance minus and the start-up circuit again activates the transistor q14. When the transistor Q14 is enabled again, the voltage potential of the input v_ of the operational amplifier U11D is directed to the voltage potential of the input V+. This will cause the conduction of the transistor q 17 to be stopped. When the input v_ of the operational amplifier UUD (instead of the anode voltage of (1)) is used as the reference voltage (presented in the circuit of FIG. 12), then the resistor R9 (which is proposed to be placed in a possible integrated circuit) External) can be a fixed value. The benefit of Ting is that several LEDs in series will no longer require the adaptation of resistors. In this way, the resistor R9 can be integrated. A diode D10 (which is a very inexpensive diode) has been added to ensure that no high negative voltage occurs at the collector of transistor Q16. The transistor (10) is in normal operation. dGe _i6_ 200919921 but not necessarily because the diode D10 is bypassed during operation. This is the possible resistor R16 output and the op amp υΐ 1D output limits this voltage. Note that the V+ input of the operational amplifier U11D can also be connected to a reference source instead of the anode of LED 1. Figure 13 illustrates an embodiment of an AM (Amplitude Modulation) buck converter, particularly for AM dimming and synchronous rectification applications, in accordance with the present invention.

Dm plus control (4) to reduce the LED light output level, and diode D2 is intended to have a high LED light output level. For high LED light output levels, a resistor determines the current value level. When the voltage across the resistor R3 reaches 0.7 v, the base will be connected to a higher voltage by the collector/emitter of the transistor, 2 the transistor Q3 will stop conducting, and the freewheeling diode (1) will begin to conduct. For low led light wheel discharge, resistor R2 & R3 is the current sense resistor. Since the value of the RH resistor R2 is higher than the value of the resistor R3, the main peak electric pick-up potential (tnp level) is determined by the resistor. Therefore, the transistor (1) will be turned off at - low current level. In Fig. 13, an operational amplifier and a resistor transistor combination (shown in Fig. u) can also replace the freewheeling diode D3. In general, there is no limit to the way in which dimming can be controlled. Fig. 14. 降压 曰 曰 曰 曰 曰 曰 曰 曰 曰 曰 曰 降压 降压 降压 降压 U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U This minimum current peak can be close to zero and then result in a critical mode converter. The operational amplifier pass level is determined by the input voltage of the op amp and the reference voltage of the input of 131652.doc 200919921 + respectively. The voltage difference between the reference voltages will cause the transistors Q18 and Q67 to be turned on at different times. A no-action area will be introduced here. The amplified sense voltage across resistor R23 is fed to the other inputs of operational amplifiers U13D and U14D. The current sensing circuit around operational amplifier U12D is a well-known component that converts current to voltage. The amplification factor of the sensing circuit A^R23/R2^ The output voltage at resistor R232tUllD, together with the reference voltage, determines the hysteresis behavior of the converter, such as the current chopping amplitude and the frequency derived therefrom. In fact, during the inactive time period, when the coil connection is floating and a high negative voltage may occur, the diode D28 has a function of a freewheeling diode to prevent the transistor Q76 from being non-conductive. Since the inactivity time is small, the diode plus 8 can be tied and one pole, and the power consumption of the diode D28 is negligible. Thus, Figure 14 relies on an example of a simple hysteresis control circuit that differs from the basic seek (= self-bias) approach, but is also applicable to bipolar transistors rather than Schottky diodes. In accordance with the present invention, a modification of a standard DC to DC converter (e.g., SOPS) is proposed that enables a standard rectifier diode to be replaced with a synchronous rectifier based on a bipolar transistor (rather than a MOSFET). As an essential component, a bipolar transistor is provided in parallel with (or instead of) a standard rectifier diode. A bipolar transistor requires only about 700 mv of base emitter voltage compared to a MOSFET (which is difficult to apply to a low output voltage S〇PS due to the high gate voltage requirement of 5 V_1() v). Further, a bipolar transistor does not have a (MOSFET intrinsic) body diode. Therefore, a very inexpensive and intrinsic efficiency is achieved in almost any type of DC-to-DC converter. Synchronization (and therefore 'high-efficiency power conversion') is possible. A further advantage of the present invention is that the power converter is self-driven and does not require a dedicated controller. The invention can be applied to: combination brake, taillight and turn 2 lamp in φ ^ π car application: (1) or buckle backlight in LCD TV; group port lamp or RCL, OLED driver in automotive applications Or general lighting applications. The present invention is to be considered as illustrative and illustrative and not restrictive. Other variations of the disclosed embodiments can also be understood and effected by those skilled in the art in the practice of the claimed invention. The disclosure of the drawings and the appended claims are in the claims. , the wording, 'includes, does not exclude other elements or steps, and does not θ θ — a '' does not exclude the plural. - A single component or other unit can perform the functions listed in the request. The fact that certain methods are recited by mutually different related claim items does not mean that the use of one of the methods is not advantageous. «No reference to any reference in the monthly proposal should be construed as limiting its scope. [Simple diagram of the diagram] Figure 1 shows the circuit diagram of the standard self-oscillating buck converter; Figure 2 shows the inductor current and the diode voltage of the converter of Figure 1; Figure 3 depicts the diode of the converter of Figure 1. Body current and diode voltage; Figure 4 depicts the diode loss for the 3 V LED voltage, 50 mA lED current, and input voltage in the converter of Figure 1. 131652.doc -19- 200919921 FIG. 5 illustrates a first embodiment of a self-oscillating buck converter according to the present invention; FIG. 6 illustrates a collector current of a bipolar transistor in the converter illustrated in FIG. And a diode voltage VD; FIG. 7 illustrates a second embodiment of a converter according to the present invention having a bipolar transistor in a standard buck converter; FIG. 8 illustrates a bipolar with a standard boost converter A third embodiment of a converter according to the invention of a transistor; FIG. 9 shows a fourth embodiment of a converter according to the invention having a bipolar transistor in a standard buck boost converter; A fifth embodiment of a converter according to the invention having a bipolar transistor in a standard flyback converter; Figure 11 shows a sixth converter according to the invention having a bipolar transistor in a standard resonant converter Embodiments; Figure 12 illustrates a seventh embodiment of a converter in accordance with the present invention, particularly a buck converter circuit for use in automotive RCL applications; Figure 13 illustrates an eighth embodiment of a converter in accordance with the present invention , especially an am step-down converter circuit; and Figure 14 shows The ninth embodiment of the converter embodiment Ming, in particular a hysteretic buck converter for LED control purposes. [Main component symbol description] Αν Magnification C Capacitor D'Dl〇'D28 Diode 131652.doc •20· 200919921 ic

Id

I〇 L Collector Current Diode Current Inductor Current DC Output Current Connected Inductor L2 Impedance LO Load Q14, Q16, Q17, Q18, Transistor Q67, Q76

Rl, R2, R3, R4, R5, resistor R9, R23, R24, R25, R26, R27, R28 S switch

Sec a , Sec b T , Ta , Tb

ΤΙ , T2 , T3 , T4

Tr

U11D, U12D, U13D, U14D Separate secondary winding bipolar transistor transistor transformer operational amplifier V- input V+ Vbe Vd Vin V〇 input base emitter voltage AC intermediate voltage DC input voltage DC output voltage 131652.doc 21 200919921 VR2 Voltage drop VS Voltage source 阻抗 Impedance Z1 First terminal Ζ 2 Second terminal Ο 1 131652.doc -22-

Claims (1)

200919921 X. Patent application scope: It is used to convert DC input A synchronous self-driving power converter, a chopper unit (s), for drawing the DC input voltage (Vin) into an alternating current intermediate voltage (vD), a rectifier unit for rectifying the alternating intermediate voltage and Outputting the rectified output voltage to the load, the rectifier unit includes a bipolar electric when the chopper unit is a closed state crystal (T, T4) as a rectifying element, and a base of the sigma bipolar transistor is coupled To a control current supply terminal, the control current supply terminal is configured to provide a control current to the base of the bipolar transistor to convert the bipolar transistor to a conducting state. 2. The synchronous self-driving power converter of claim 1, further comprising one or more of a coupling σ to 5 斩 chopper unit (s), the bipolar transistor (T, T4), and the load (LO) Reactive components, in particular one or more capacitors (C), inductive components (L) and/or transformers (Tr). 3. A synchronous self-driving power converter as in item 1, which further comprises an impedance (Ζ) 'one of its terminals (Ζ1) is coupled to the base of the bipolar transistor (Τ, D) Used to supply the control current. 4. A synchronous self-driving power converter as claimed in claims 2 and 3, wherein the other terminal (Ζ2) of the impedance of 7° (Ζ) is coupled to the output voltage (V〇). 5 · Synchronous self-driving power converter of item 1 of the month, wherein the control circuit L is derived from the output voltage (V〇) or the current reference voltage. 131652.doc 200919921 6 . The synchronous self-driving power converter of 5 1 -1, wherein the rectifier Y-progress comprises a rectifier diode (D) coupled to the bipolar electric solar body ( T, T4) between the emitter and the collector. A synchronous self-driving power converter such as the whistle of claim 1, wherein the reactive element is an inductor (L). The synchronous self-driving power converter of claim 1 wherein the resistance is: a transformer (Tr), the transformer is used to transform the input voltage into two, an intermediate voltage, and wherein the chopper unit (S) It is coupled between a primary winding (pdm) of the transformer (Tr) and an input voltage supply unit. 9. The synchronous self-driving power converter of claim 8, wherein the rectifier is a pair of bipolar transistors (Ta, Tb), wherein the impedance unit comprises two impedances τ (Za, Zb), The terminals of the elements that are not coupled to the base of the associated bipolar transistor (Ta, Tb) are coupled to each other and to one of the transformers (Tr) to separate the secondary windings (Sec-a, neutrons) 1 驱动 drive, 丨 used to provide DC drive power and / or DC drive current to - load (L0), especially to - LED unit, - backlight single 70 LCD single or a rear combination lamp unit, The driver includes a synchronous self-driving power converter such as claim 1, which is used to convert the input voltage (Vin) into the DC drive voltage (V〇) and/or the DC drive current (i〇). A method of driving a power converter to convert a DC input voltage (Vin) into a DC output power (v〇) and/or a DC output current (i〇) to supply a load (L0) includes the following steps: Grab 131652.doc 200919921 Capture the DC input The input voltage (Vjn) becomes an alternating current intermediate voltage (ν〇), and the alternating current intermediate voltage is rectified by a rectifier unit, the rectifier unit includes a bipolar transistor (D, T4), and the rectified wheel output voltage is output to The load, turning on and off the coupling of the output voltage to the rectifier unit, and when the chopper is in a closed state, providing a control current to the base of the bipolar transistor to convert the bipolar transistor to a conducting state . 131652.doc