CN1286260C - Novel synchronous rectified drive circuit of reversed excitation circuit - Google Patents
Novel synchronous rectified drive circuit of reversed excitation circuit Download PDFInfo
- Publication number
- CN1286260C CN1286260C CNB021225710A CN02122571A CN1286260C CN 1286260 C CN1286260 C CN 1286260C CN B021225710 A CNB021225710 A CN B021225710A CN 02122571 A CN02122571 A CN 02122571A CN 1286260 C CN1286260 C CN 1286260C
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- circuit
- synchronous rectifier
- diode
- gate pole
- reversed excitation
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Abstract
The present invention discloses a new synchronous rectification drive circuit of a flyback circuit. A gate charging circuit of a synchronous rectifier tube S2 comprises an NPN triode Q4, a resistor R3 and a diode D3, wherein the gate charging circuit of the synchronous rectifier tube S2 comprises an NPN triode Q3, a diode D2, a resistor R2 and a capacitor C2. The present invention is characterized in that the circuit can ensure that the synchronous rectifier tube S2 is closed before a main switch tube S1 is opened to avoid common conduction; at the same time, since a secondary circuit of the drive transformer Tr2 is composed of discrete components, the circuit structure which is simplified has high reliability and low cost.
Description
Technical field
The present invention relates to Switching Power Supply, specifically a kind of novel synchronous rectified drive circuit of circuit of reversed excitation.
Background technology
Traditional circuit of reversed excitation (promptly with the circuit of reversed excitation of Schottky diode as the output rectifier diode, as shown in Figure 1) because its circuit structure is simple, use very extensive in the small-power buffer circuit by reason such as the components and parts number is few, and is with low cost.But along with the develop rapidly of Modern High-Speed very lagre scale integrated circuit (VLSIC), the supply voltage of integrated circuit descends thereupon, and operating current but increases thereupon.Therefore when low-voltage, high-current was exported, if still adopt Schottky diode as the output rectifier diode, the conduction loss on the output diode can be very big so.And because the conducting resistance of low-voltage power MOSFET is very little, for example the conducting resistance of the power MOSFET of 20A only is 6-8m Ω.Promptly be applied to the DC-DC Switching Power Supply of low pressure output the beginning of the eighties successively, be called synchronous rectifier (Synchronous Rectifier).In order to reduce conduction loss, synchronous rectification also is applied in the circuit of reversed excitation as shown in Figure 2.
The type of drive of synchronous rectifier has outer (Externally-driven) and self-driven (Self-driven) two kinds of driving.The characteristics of self-driven mode be circuit structure simply but common conduction problem is arranged.Outer type of drive (as shown in Figure 3) has increased complexity, cost and the corresponding reliability decrease that makes circuit of circuit though that utilization is got up is more flexible.
Summary of the invention
The present invention will solve be existing synchronous rectification driving circuit in the conduction loss that reduces rectifying tube, the common conducting that can produce main switch and synchronous rectifier makes the problem of the reliability decrease of circuit.The technical scheme that addresses the above problem employing is: the novel synchronous rectified drive circuit of circuit of reversed excitation comprises main switch S
1, synchronous rectifier S
2, main transformer Tr1, PWM controller U
1, output capacitance C
oWith driving transformer Tr2, described driving transformer Tr2 secondary is provided with synchronous rectifier S
2Gate pole charging circuit and gate pole discharge circuit, and main switch S
1Open the time-delay T
D1Greater than synchronous rectifier S
2T discharge time
D2Described synchronous rectifier S
2The gate pole charging circuit comprise a NPN type triode Q
4, collector electrode is connected to power positive end, series resistor R between collector electrode and the base stage
3, emitter and diode D
3Anode be connected to synchronous rectifier S after linking to each other
2Gate pole, base stage and diode D
3Negative electrode link to each other; Described synchronous rectifier S
2The gate pole discharge circuit comprise a NPN type triode Q
3, its emitter and diode D
2Anode be connected to power supply negative terminal, base stage and diode D
2Negative electrode be connected to the anode of driving transformer Tr2 secondary after linking to each other, collector electrode links to each other with charging circuit.
The novel synchronous rectified drive circuit of circuit of reversed excitation of the present invention is as long as circuit satisfies T
D1＞T
D2, synchronous rectifier S
2Just can be at main switch S
1Turn-off before opening, thereby avoid common conducting.The secondary circuit of driving transformer Tr2 is made of discrete component, has simplified circuit structure, but the reliability height is with low cost.
Described triode Q
3Base stage and diode D
2Series resistor R between the anode of the link of negative electrode and driving transformer Tr2 secondary
2, can improve the antijamming capability of circuit, prevent triode Q
3Mislead.Described resistance R
2Two ends shunt capacitance C
2, can quicken triode Q
3Open-minded.The former limit series connection of described driving transformer Tr2 voltage-stabiliser tube Z
1, can reduce transformer Tr
2Former limit driving voltage, thereby can reduce transformer Tr
2Voltagesecond product, make transformer Tr
2Volume further reduce.Described main switch S
1Gate pole on series connection voltage-stabiliser tube Z
2, can further postpone main switch S
1Service time, guarantee synchronous rectifier S
2At main switch S
1Just turn-off before opening.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples.
Fig. 1 is the circuit of reversed excitation of Schottky diode as the output rectifier diode.
Fig. 2 is the circuit of reversed excitation that is output as synchronous rectification.
Fig. 3 is the outer synchronous rectification circuit of reversed excitation that drives.
Fig. 4 (A) is the novel synchronous rectified drive circuit of circuit of reversed excitation of the present invention.
Fig. 4 (B) is the main waveform of each point in Fig. 4 (A) circuit.
Fig. 5 is that the present invention has increased voltage-stabiliser tube Z
1, Z
2Synchronous rectification driving circuit.
Embodiment
With reference to Fig. 4 (A), the novel synchronous rectified drive circuit of circuit of reversed excitation comprises main switch S
1, synchronous rectifier S
2, main transformer Tr1, PWM controller U
1, output capacitance C
oWith driving transformer Tr2, synchronous rectifier S
2The gate pole charging circuit comprise a NPN triode Q
4, its collector electrode is connected to power positive end, series resistor R between collector electrode and the base stage
3, emitter and diode D
3Anode be connected to synchronous rectifier S after linking to each other
2Gate pole, base stage and diode D
3Negative electrode be connected to Q after linking to each other
3Collector electrode.Described synchronous rectifier S
2The gate pole discharge circuit comprise NPN triode Q
3, emitter and diode D
2Anode be connected to power supply negative terminal, base stage and diode D
2Negative electrode link to each other, again with one by resistance R
2With capacitor C
2Be connected to the anode of driving transformer Tr2 secondary after the circuit series connection in parallel.
Fig. 4 (B) then is the main waveform of each point, wherein V in the circuit working
GsBe PWM controller U
1Output level, V
Gs1Be main switch S
1Driving voltage waveform, V
Gs2Be synchronous rectifier S
2Driving voltage waveform, V
pBe the original edge voltage waveform of driving transformer Tr2, V
Gp3Be triode Q
3The voltage waveform of base stage-emitter-base bandgap grading, V
Gq4Be triode Q
4The voltage waveform of base stage-emitter-base bandgap grading.
The operation principle of foregoing circuit is:
(1) t＜t
1The time, the output level V of PWM controller
GsBe zero.T=t
1Constantly, V
GsUpset is being for just, driving transformer original edge voltage V
pSimultaneously for just, triode Q
3Conducting (capacitor C
2Can quicken triode Q
3Open-minded), synchronous rectifier S
2Gate charge by triode Q
3(be T its discharge time in release
D2), synchronous rectifier S
2Turn-off.And simultaneously, V
GsPass through resistance R
1To main switch S
1Gate pole electric capacity charging, work as V
Gs1Voltage still less than V
T1(V
T1Be main switch S
1Open threshold voltage) time, main switch S
1Still (it is opened time-delay and is T to be in off state
D1).As long as satisfy:
T
D1＞T
D2(1) synchronous rectifier S
2Just can be at main switch S
1Turn-off before opening, thereby avoid common conducting.After this, V
Gs1Voltage continue to increase, work as V
Gs1Greater than V
T1The time, main switch S
1Conducting.
(2) work as t=t
2Constantly, PWM controller U
1Output level V
GsUpset is zero.Main switch S
1Turn-off.And simultaneously, driving transformer original edge voltage V
pFor negative, triode Q
3Turn-off triode Q
4The voltage of base stage-emitter-base bandgap grading for just, thereby make triode Q
4Conducting, voltage V
CBy triode Q
4To synchronous rectifier S
2Gate pole electric capacity charging, V
Gs2Rise.Work as V
Gs2Greater than V
T2(V
T2Be synchronous rectifier S
2Open threshold voltage) time, synchronous rectifier S
2Conducting.
Circuit shown in Figure 5 is on the basis of Fig. 4 embodiment, at the former limit series connection of driving transformer Tr2 voltage-stabiliser tube Z
1, can reduce transformer Tr
2Former limit driving voltage, thereby can reduce transformer Tr
2Voltagesecond product, make transformer Tr
2Volume further reduce.At main switch S
1Gate pole on the series connection voltage-stabiliser tube Z
2, further postpone main switch S
1Service time, guarantee synchronous rectifier S
2At main switch S
1Just turn-off before opening.
Claims (5)
1, the synchronous rectification driving circuit of circuit of reversed excitation comprises main switch S
1, synchronous rectifier S
2, main transformer Tr1, PWM controller U
1, output capacitance C
oWith driving transformer Tr2, it is characterized in that being provided with synchronous rectifier S at described driving transformer Tr2 secondary
2Gate pole charging circuit and gate pole discharge circuit, and main switch S
1Open the time-delay T
D1Greater than synchronous rectifier S
2T discharge time
D2Described synchronous rectifier S
2The gate pole charging circuit comprise a NPN type triode Q
4, collector electrode is connected to power positive end, series resistor R between collector electrode and the base stage
3, emitter and diode D
3Anode be connected to synchronous rectifier S after linking to each other
2Gate pole, base stage and diode D
3Negative electrode link to each other; Described synchronous rectifier S
2The gate pole discharge circuit comprise a NPN type triode Q
3, its emitter and diode D
2Anode be connected to power supply negative terminal, base stage and diode D
2Negative electrode be connected to the anode of driving transformer Tr2 secondary after linking to each other, collector electrode links to each other with charging circuit.
2, the synchronous rectification driving circuit of circuit of reversed excitation as claimed in claim 1 is characterized in that described triode Q
3Base stage and diode D
2Series resistor R between the anode of the link of negative electrode and driving transformer Tr2 secondary
2
3, the synchronous rectification driving circuit of circuit of reversed excitation as claimed in claim 2 is characterized in that described resistance R
2Two ends shunt capacitance C
2
4,, it is characterized in that the former limit series connection of described driving transformer Tr2 voltage-stabiliser tube Z as the synchronous rectification driving circuit of any one described circuit of reversed excitation of claim 1～3
1
5, the synchronous rectification driving circuit of circuit of reversed excitation as claimed in claim 4 is characterized in that described main switch S
1Gate pole on series connection voltage-stabiliser tube Z
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021225710A CN1286260C (en) | 2002-06-06 | 2002-06-06 | Novel synchronous rectified drive circuit of reversed excitation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021225710A CN1286260C (en) | 2002-06-06 | 2002-06-06 | Novel synchronous rectified drive circuit of reversed excitation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1464629A CN1464629A (en) | 2003-12-31 |
| CN1286260C true CN1286260C (en) | 2006-11-22 |
Family
ID=29743278
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021225710A Expired - Fee Related CN1286260C (en) | 2002-06-06 | 2002-06-06 | Novel synchronous rectified drive circuit of reversed excitation circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1286260C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7894217B2 (en) | 2007-08-31 | 2011-02-22 | Innocom Technology (Shenzhen) Co., Ltd. | DC to DC converter |
| US10917089B2 (en) | 2017-04-07 | 2021-02-09 | Astec International Limited | Stacked MOSFET circuits and methods of operating stacked MOSFET circuits |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316726C (en) * | 2004-06-11 | 2007-05-16 | 伊博电源（杭州）有限公司 | Self-driving circuit of antilaser converter synchronous rectifier |
| CN101552558B (en) * | 2008-12-31 | 2011-05-25 | 北京新雷能科技股份有限公司 | Synchronous rectification driving circuit of flyback circuit |
| CN101515761B (en) * | 2009-04-03 | 2011-01-05 | 北京新雷能有限责任公司 | Synchronous rectification circuit of reverse excitation circuit provided with adjustable dead time |
| CN102315759B (en) * | 2010-07-05 | 2015-08-12 | 通用电气公司 | There is raster data model controller circuitry and the power-up circuit thereof of anti saturation circuit |
| TWI504113B (en) * | 2012-11-14 | 2015-10-11 | Lite On Technology Corp | Fly-back power converter and electronic apparatus |
| US9735694B2 (en) * | 2015-06-19 | 2017-08-15 | Sanken Electric Co., Ltd. | Integrated circuit and switching power-supply device with charging control circuit |
| CN105391302A (en) * | 2015-11-13 | 2016-03-09 | 航天科工惯性技术有限公司 | Fly-back synchronous rectification control circuit |
-
2002
- 2002-06-06 CN CNB021225710A patent/CN1286260C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7894217B2 (en) | 2007-08-31 | 2011-02-22 | Innocom Technology (Shenzhen) Co., Ltd. | DC to DC converter |
| CN101378230B (en) * | 2007-08-31 | 2011-06-15 | 群康科技(深圳)有限公司 | Switch power supply circuit |
| US10917089B2 (en) | 2017-04-07 | 2021-02-09 | Astec International Limited | Stacked MOSFET circuits and methods of operating stacked MOSFET circuits |
| US11381240B2 (en) | 2017-04-07 | 2022-07-05 | Astec International Limited | Stacked MOSFET circuits and methods of operating stacked MOSFET circuits |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1464629A (en) | 2003-12-31 |
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