CN201018415Y - High efficiency switching power converter - Google Patents
High efficiency switching power converter Download PDFInfo
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- CN201018415Y CN201018415Y CNU2006201198379U CN200620119837U CN201018415Y CN 201018415 Y CN201018415 Y CN 201018415Y CN U2006201198379 U CNU2006201198379 U CN U2006201198379U CN 200620119837 U CN200620119837 U CN 200620119837U CN 201018415 Y CN201018415 Y CN 201018415Y
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Abstract
The utility model relates to a switching power converter which comprises a first transistor and a second transistor; wherein the first transistor and the second transistor are in series with a transformer in order to provide the higher switching efficiency. A charge pump circuit is coupled to a drive circuit in order to provide the power supply to drive the first transistor. A third transistor is connected between the transformer and the ground terminal in order to help to switch the transformer and charge up the charge pump circuit. A switching control circuit is coupled to the output end of the switching power converter in order to produce a first switching signal and a second switching signal used to adjust the switching power converter. The first switching signal drives the first transistor and the second transistor through coupling. The second switching signal drives the third transistor through coupling.
Description
Technical Field
The present invention relates to power converters, and more particularly to switching power converters and switching regulators.
Background
Power converters have been used to convert unregulated power sources into regulated voltage and/or current sources. The transformer of the power converter is arranged to provide isolation between the input power source and the application device for safety purposes. FIG. 1 shows a conventionalThe switching power converter of (1). The transistor 5 is connected to the primary winding N of the transformer 40 P For switching the transformer 40. Thus, the secondary winding N of the transformer 40 S A power supply is generated that is coupled to the output of the power converter through a rectifier and filter 50. Due to the geometrical limitations of the transformer, a leakage inductor 45 will be created in the transformer 40. Inductance value L of leakage inductor 45 L Indicating no transfer to the secondary winding N of the transformer 40 S The energy of (c). A worse coupling between the primary and secondary windings will result in a higher leakage inductance of the transformer. Thus, smaller transformers typically contain higher leakage inductance. Power P generated by leakage inductor 45 L It can be expressed as follows,
wherein, I M Is the switching current of the transformer 40; f S Is the switching frequency of the power converter.
SUMMERY OF THE UTILITY MODEL
The utility model provides a switch power converter, it utilizes the switching of first transistor and second transistor, comes to the energy conversion of the leakage inductor of transformer and/or magnetization inductor to the input voltage in, and then reduces switch power converter's power consumption effectively.
The utility model provides a method and a device which can save the power of leakage inductance and realize higher efficiency for a power converter. It includes a first transistor connected from an input voltage of a switching power converter to a first end of a primary winding of a transformer. The second transistor is connected from the second end of the primary winding of the transformer to ground. A first diode is connected from the second end of the primary winding to the input voltage. A second diode is coupled from ground to the first end of the primary winding. The third transistor is coupled from the first end of the primary winding to ground. A drive circuit is coupled to the first terminal of the primary winding and the first transistor for driving the first transistor. The charge pump circuit is connected to the drive circuit for providing power to the drive circuit. The switching control circuit is coupled to an output of the power converter to generate a first switching signal and a second switching signal for regulating the switching power converter. The first switching signal is coupled to drive the first transistor and the second transistor at a first pulse width. The second switching signal is coupled to drive the third transistor at a second pulse width.
In summary, the present invention provides a switching power converter, which utilizes a first transistor and a second transistor coupled to a transformer, so that a leakage inductor and/or a magnetization inductor of the transformer can convert energy formed by the leakage inductor and/or the magnetization inductor into an input voltage under the control of the first transistor and the second transistor. Therefore, compared with the prior art, the switching power converter of the present invention does not need an additional circuit (such as a snubber circuit) to consume the energy generated by the leakage inductor of the transformer, thereby effectively reducing the power consumption of the switching power converter.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the detailed description, serve to explain the principles of the invention.
Fig. 1 shows a conventional power converter.
Fig. 2 is a schematic circuit of a high efficiency switching power converter according to an embodiment of the present invention.
Fig. 3A-3E show the operational phases of each switching cycle of a switching power converter according to an embodiment of the present invention.
Fig. 4 shows a waveform of a switching signal according to an embodiment of the present invention.
Fig. 5 is a switching control circuit of a switching power converter according to an embodiment of the present invention.
Fig. 6 shows a circuit schematic of an oscillating circuit according to an embodiment of the invention.
Detailed Description
Fig. 2 shows a switching power converter according to an embodiment of the present invention. The switching power converter may be a power converter or a switching regulator. The transformer 10 comprises a primary winding N P And a secondary winding N S . Primary winding N of transformer 10 P Having a first end and a second end. Secondary winding N of transformer 10 S Coupled to the output of the switching power converter through a rectifier-filter 50. Transistor 11 receives input voltage V from IN Is connected to the primary winding N P The first end of (a). Transistor 11 includes a parasitic diode 16. Transistor 21 secondary winding N P Is connected to ground. Transistor 21 includes a parasitic diode 26. Diode 37 slave primary winding N P Is connected to the input voltage V IN . Diode 35 is coupled from ground to primary winding N P The first end of (a). Transistor 31 is connected from primary winding N P Is coupled to ground. The drive circuit 90 is coupled to the primary winding N P And transistor 11 is used to drive transistor 11. The buffer circuit 95 is connected to the transistor 21 for driving the transistor 21.Diode 80 slave supply voltage V B Connected to the capacitor 85. The diode 80 and the capacitor 85 form a charge pump circuit that is connected to the drive circuit 90 to supply power to the drive circuit 90. When the transistor 31 is turned on, the power supply voltage V B The capacitor 85 will be charged through the diode 80. The switching control circuit 100 is coupled to the output V of the power converter through the secondary circuit 60 O . The secondary circuit 60 is used to generate a feedback signal based on the output of the power converter. The devices (e.g., optocouplers) of the secondary circuit 60 will provide isolation. The switching control circuit 100 is based on the feedback signal V FB To generate a switching signal S 1 And a switching signal S 2 To regulate the output of the power converter. Switching signal S 1 Coupled to drive transistor 11 and transistor 21. Switching signal S 2 Coupled to drive transistor 31.
Fig. 3A-3E show the operating phases of each switching cycle of the power converter. As shown in fig. 3A, at an operating phase T 1 During which the transistor 11 and the transistor 21 are turned on. Switching the current I M The energy is transferred to the transformer 10 by conduction. FIG. 3B shows an operating phase T 2 With transistor 11 and transistor 21 turned off. The energy of the leakage inductor and/or the magnetizing inductor of the transformer 10 will become a loop current to retrieve the energy to the input voltage V through the diode 37 and the diode 35 IN . As shown in fig. 3C, transistor 31 is now conducting for soft switching (zero voltage conduction). In the operating phase T 3 During which the voltage of the capacitor 27 is equal to the input voltage V IN . Capacitor 27 is a parasitic capacitor of transistor 21. In addition, the supply voltage V B The capacitor 85 will be charged for the charge pump through the diode 80 and the transistor 31. As shown in FIG. 3D, at an operating phase T 4 When the transformer 10 is completely discharged, the energy of the capacitor 27 is transferred to the transformer 10 through the transistor 31. FIG. 3E is an operation phase T 5 Wherein transistor 31 is turned off. Thus, the energy of transformer 10 will reverse the charging of capacitor 17 and capacitor 27, which is helpful in thatSoft switching of transistors 11 and 21 in the next switching cycle. The capacitor 17 isParasitic capacitors of transistor 11.
FIG. 4 shows the switching signal S 1 And S 2 In which the switching signal S is disabled 1 After that and while the switching signal S is enabled 2 Previously generated delay time T D1 . In addition, the switching signal S is disabled 2 After that and while the switching signal S is enabled 1 Previously generated delay time T D2 . Delay time T D1 Is an operating phase T 2 A period of time. Delay time T D2 Is an operating phase T 5 Of the time period (c). Switching signal S 1 Coupled to drive transistor 11 and transistor 21 through drive circuit 90 and buffer circuit 95, respectively. Switching signal S 2 Connected to drive transistor 31. Transistor 11 and transistor 21 are driven at a first pulse width. The transistor 31 is driven with a second pulse width.
Fig. 5 is a switching control circuit 100 according to an embodiment of the present invention. The switching control circuit 100 includes an oscillation circuit 200 for generating a pulse signal PLS and a RAMP signal RAMP. The pulse signal PLS is connected to the inverter 115. The output of inverter 115 is connected to enable flip-flop 120. The output of flip-flop 120 is connected to the input of and gate (andsgate) 150. The other input of and gate 150 is connected to the output of inverter 115. The output of the AND gate generates a switching signal S 1 . RAMP signal RAMP and feedback signal V FB Coupled to an operational amplifier 110. The output of the op-amp is used to disable the flip-flop 120. The transistor 160, the current source 170, and the capacitor 175 form a delay circuit. The input of transistor 160 is connected to the output of flip-flop 120. Capacitor 175 is connected to an input of and gate 180. The other input of and gate 180 is coupled to the output of flip-flop 120 through inverter 165. The output of the AND gate 180 generates the switching signal S 2 . The current of the current source 170 and the capacitance of the capacitor 175 determine the delay time T D1 。
Fig. 6 shows a schematic diagram of an oscillating circuit 200 according to an embodiment of the invention. Current source 210 onThe over switch 215 is connected to a capacitor 230. The current source 220 is connected to the capacitor 230 through the switch 225. With reference voltage V H Is connected to the capacitor 230. Having a reference voltage V L Is connected to the capacitor 230. Nand gates (NANDgate) 261 and 262 form a latch circuit. The input of the nand gate 261 is connected to the output of the comparator 251. The input of nand gate 262 is connected to the output of comparator 252. The output of the nand gate 261 generates a pulse signal PLS. The switch 225 is controlled by the pulse signal PLS. The switch 215 is controlled by the pulse signal PLS via an inverter 250. Accordingly, the RAMP signal RAMP is generated at the capacitor 230. Accordingly, the current of the current source 220 and the capacitance of the capacitor 230 determine the pulse width and delay time T of the pulse signal PLS D2 。
Those skilled in the art will readily appreciate that various modifications and changes may be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims (8)
1. A switching power converter, characterized in that it comprises:
a transformer comprising a primary winding having a first end and a second end, a secondary winding coupled to an output of the switching power converter;
a first transistor connected from an input voltage to the first end of the primary winding;
a second transistor connected from the second end of the primary winding to ground;
a drive circuit coupled to the first terminal of the primary winding and the first transistor to drive the first transistor;
a charge pump circuit connected to the drive circuit so as to supply power to the drive circuit;
a diode connected from the second end of the primary winding to the input voltage;
a third transistor coupled from the first end of the primary winding to the ground; and
a switching control circuit coupled to the output of the switching power converter so as to generate switching signals for regulating the switching power converter, wherein switching signals include a first switching signal coupled to drive the first transistor and the second transistor and a second switching signal coupled to drive the third transistor.
2. The switching power converter of claim 1, further comprising a second diode coupled from the ground to the first end of the primary winding.
3. The switching power converter according to claim 1, further comprising a buffer circuit connected to the second transistor for driving the second transistor.
4. The switching power converter of claim 1, wherein the charge pump circuit comprises:
a capacitor connected to the driving circuit;
a charge pump diode connected from a supply voltage to the capacitor;
wherein the power supply voltage charges the capacitor through the charge pump diode when the third transistor is turned on.
5. A power converter including a transformer, comprising:
a first transistor connected from an input voltage to the transformer;
a second transistor connected from the transformer to ground;
a driving circuit coupled to the first transistor for driving the first transistor;
a buffer circuit connected to the second transistor for driving the second transistor;
a charge pump circuit connected to the drive circuit so as to supply power to the drive circuit;
a first diode connected from the transformer to the input voltage;
a second diode coupled from the ground to the transformer; and
a switching control circuit coupled to an output of the switching power converter to generate a switching signal to regulate the power converter;
wherein the switching signal is coupled to the driving circuit and the buffer circuit to drive the first transistor and the second transistor, wherein the first transistor and the second transistor are driven with a pulse width.
6. The power converter of claim 5, wherein the charge pump circuit comprises:
a capacitor connected to the driving circuit; and
a charge pump diode connected from a supply voltage to the capacitor;
wherein the power supply voltage charges the capacitor through the charge pump diode when the first and second transistors are off.
7. A switching regulator having a transformer, characterized by comprising:
a first transistor connected from an input voltage to the transformer;
a second transistor connected from the transformer to ground;
a third transistor connected from the transformer to the ground;
a diode connected from the transformer to the input voltage; and
a switching control circuit coupled to an output of the switching regulator to generate a first switching signal and a second switching signal to regulate the switching regulator;
wherein the first switching signal is coupled to drive the first transistor and the second transistor; the second switching signal is coupled to drive the third transistor.
8. The switching regulator of claim 7, further comprising a second diode coupled from the ground to the transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201198379U CN201018415Y (en) | 2006-08-02 | 2006-08-02 | High efficiency switching power converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201198379U CN201018415Y (en) | 2006-08-02 | 2006-08-02 | High efficiency switching power converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201018415Y true CN201018415Y (en) | 2008-02-06 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2006201198379U Expired - Fee Related CN201018415Y (en) | 2006-08-02 | 2006-08-02 | High efficiency switching power converter |
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| CN (1) | CN201018415Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102223072A (en) * | 2010-06-25 | 2011-10-19 | 崇贸科技股份有限公司 | Double-switch flyback type power converter with wide input voltage range |
| CN102809642A (en) * | 2012-08-03 | 2012-12-05 | 河海大学 | Method for determining hydrogeological parameters of aquitard |
-
2006
- 2006-08-02 CN CNU2006201198379U patent/CN201018415Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102223072A (en) * | 2010-06-25 | 2011-10-19 | 崇贸科技股份有限公司 | Double-switch flyback type power converter with wide input voltage range |
| TWI469488B (en) * | 2010-06-25 | 2015-01-11 | System General Corp | Dual switches flyback power converter with wide input voltage range |
| CN102809642A (en) * | 2012-08-03 | 2012-12-05 | 河海大学 | Method for determining hydrogeological parameters of aquitard |
| CN102809642B (en) * | 2012-08-03 | 2015-04-29 | 河海大学 | Method for determining hydrogeological parameters of aquitard |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |