CN103078512A - Flyback switch circuit of switch frequency hopping - Google Patents
Flyback switch circuit of switch frequency hopping Download PDFInfo
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- CN103078512A CN103078512A CN 201210568123 CN201210568123A CN103078512A CN 103078512 A CN103078512 A CN 103078512A CN 201210568123 CN201210568123 CN 201210568123 CN 201210568123 A CN201210568123 A CN 201210568123A CN 103078512 A CN103078512 A CN 103078512A
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Abstract
The invention provides a flyback switch circuit of switch frequency hopping, solving the problem that the flyback switch circuit is low in efficiency under a light load state. The flyback switch circuit comprises an input port, an output port, a rectification unit, a primary side power switch, an auxiliary side diode, an output capacitor, a feedback component, an auxiliary side connecting resistor, a primary side connecting resistor, a Zener diode, a voltage comparator, a selection switch, a frequency comparator, a sawtooth wave generator and a control and drive circuit. With the adoption of the flyback switch circuit, the efficiency of the flyback switch circuit is improved under the light load state.
Description
Technical field
The present invention relates to electronic technology field, particularly a kind of switch flyback switch circuit of switching frequency saltus step.
Background technology
Switch flyback switch circuit is called again single-ended flyback or buck-boost transducer, and the voltage of the comparable power supply of its output voltage is high or low.Typical case's switch flyback switch circuit as shown in Figure 1, this switch flyback switch circuit comprises: input port receives input voltage vin; Output port provides output voltage V o; Rectification unit Rec is coupled to input port and receives input voltage vin; Transformer comprises former limit winding T1 and secondary winding T2, and described former limit winding T1 is coupled to rectification unit Rec; Former limit power switch S is coupled in former limit winding T1 and former limit with reference between the ground; Secondary diode D is coupled between secondary winding T2 and the output port; Output capacitor Co is coupled in output port and with reference between the ground.The switch periods of existing switch flyback switch circuit is triggered by the clock signal of fixed frequency usually, and namely its switching frequency is the clock frequency of fixed numbers.Under heavy condition, fixing switching frequency can make switch flyback switch circuit keep high efficiency.Yet under light condition, if the switching frequency under switching frequency or the heavy condition, meeting is so that the Efficiency Decreasing of switch flyback switch circuit.
Summary of the invention
The present invention proposes a kind of switch flyback switch circuit of switching frequency saltus step, has solved existing switch flyback switch circuit inefficient problem under light condition.
Technical scheme of the present invention is achieved in that
A kind of switch flyback switch circuit of switching frequency saltus step comprises: input port receives input voltage; Output port provides output voltage; Rectification unit is coupled to input port and receives input voltage, produces commutating voltage; Transformer comprises former limit winding and secondary winding, and its limit, Central Plains winding and secondary winding respectively have the first terminal and the second terminal, and the first terminal of former limit winding is coupled to rectification unit and receives commutating voltage, and the second terminal of secondary winding connects secondary with reference to ground; Former limit power switch is coupled in the second terminal of former limit winding and former limit with reference between the ground; The secondary diode is coupled between the first terminal and output port of secondary winding; Output capacitor is coupled in output port and secondary with reference between the ground; Feedback component comprises secondary part and former limit part; Secondary contact resistance, Zener diode and former limit contact resistance, wherein the secondary part of feedback component, secondary contact resistance and Zener diode are coupled in series in output port and secondary with reference between the ground, to produce feedback voltage in the former limit of feedback component part; Voltage comparator, have in-phase input end, inverting input and lead-out terminal, its in-phase input end threshold level voltage, its inverting input is coupled to former limit with reference to ground via former limit part and the former limit contact resistance of feedback component, to receive feedback voltage, its lead-out terminal produces voltage comparison signal; Selector switch, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples the first frequency signal, its second terminal couples the second frequency signal, its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator, and its 3rd terminal provides frequency reference signal according to voltage comparison signal; Frequency comparator has in-phase input end, inverting input and lead-out terminal, and its inverting input is coupled to the 3rd terminal receive frequency reference signal of selector switch, and its lead-out terminal provides clock signal; Sawtooth generator is coupled to the lead-out terminal receive clock signal of frequency comparator, and provides the in-phase input end of sawtooth signal to frequency comparator based on clock signal; Control and drive circuit are coupled to the lead-out terminal receive clock signal of frequency comparator, and based on clock signal, produce switching drive signal, to control the break-make of former limit power switch.
Alternatively, described feedback component comprises photoelectrical coupler.
Alternatively, when feedback voltage greater than threshold voltage, the 3rd terminal of described selector switch is connected to its first terminal, so that the inverting input of frequency comparator receives the first frequency signal; When feedback voltage less than threshold voltage, the 3rd terminal of described selector switch is connected to its second terminal, so that the inverting input of frequency comparator receives the second frequency signal.
Alternatively, described first frequency signal is greater than the second frequency signal.
Alternatively, described sawtooth generator comprises: charging current source, charging capacitor and reset switch, three's coupled in parallel at the in-phase input end of frequency comparator with reference to ground between, wherein said reset switch further comprises control terminal, and described control terminal is coupled to the lead-out terminal receive clock signal of frequency comparator.
Alternatively, described rectification unit comprises the rectifier circuit that is comprised of four diodes.
The invention has the beneficial effects as follows: can improve the efficient of switch flyback switch circuit under light condition.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art, apparently, accompanying drawing in the following describes only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the typical circuit structural representation of existing switch flyback switch circuit;
Fig. 2 is the electrical block diagram of the switch flyback switch circuit 100 of a kind of switching frequency saltus step of the present invention;
Fig. 3 is the timing waveform signal of clock signal clk, sawtooth signal Vsw, frequency reference signal Vfr and output voltage V o in the switch flyback switch circuit 100 of switching frequency saltus step shown in Figure 2.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not paying the every other embodiment that obtains under the creative work prerequisite.
As shown in Figure 2, the switch flyback switch circuit 100 of switching frequency saltus step of the present invention comprises: input port 101 receives input voltage vin; Output port 102 provides output voltage V o; Rectification unit 103 is coupled to input port 101 and receives input voltage vin, produces commutating voltage; Transformer, comprise former limit winding 104-1 and secondary winding 104-2, its limit, Central Plains winding 104-1 and secondary winding 104-2 respectively have the first terminal and the second terminal, the first terminal of former limit winding 104-1 is coupled to rectification unit 103 and receives commutating voltage, and the second terminal of secondary winding 104-2 connects secondary with reference to ground; Former limit power switch 105 is coupled in the second terminal of former limit winding 104-1 and former limit with reference between the ground; Secondary diode 106 is coupled between the first terminal and output port 102 of secondary winding 104-2; Output capacitor 107 is coupled in output port 102 and secondary with reference between the ground; Feedback component comprises secondary part 108-1 and former limit part 108-2; Secondary contact resistance 109, Zener diode 110 and former limit contact resistance 111, wherein the secondary part 108-1 of feedback component, secondary contact resistance 109 and Zener diode 110 are coupled in series in output port 102 and secondary with reference between the ground, produce feedback voltage Vfb with the former limit part 108-2 in feedback component; Voltage comparator 112, have in-phase input end, inverting input and lead-out terminal, its in-phase input end threshold level voltage Vth, its inverting input is coupled to former limit with reference to ground via former limit part 108-2 and the former limit contact resistance 111 of feedback component, to receive feedback voltage Vfb, its lead-out terminal produces voltage comparison signal; Selector switch 113, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples first frequency signal Vf1, its second terminal couples second frequency signal Vf2, its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator 112, and its 3rd terminal provides frequency reference signal Vfr according to voltage comparison signal; Frequency comparator 114 has in-phase input end, inverting input and lead-out terminal, and its inverting input is coupled to the 3rd terminal receive frequency reference signal Vfr of selector switch 113, and its lead-out terminal provides clock signal clk; Sawtooth generator 115 is coupled to the lead-out terminal receive clock signal CLK of frequency comparator 114, and provides the in-phase input end of sawtooth signal Vsw to frequency comparator 114 based on clock signal clk; Control and drive circuit 116 are coupled to the lead-out terminal receive clock signal of frequency comparator 114, and based on clock signal, produce switching drive signal, to control the break-make of former limit power switch 105.
Preferably, described sawtooth generator 115 comprises: charging current source 11, charging capacitor 12 and reset switch 13, three's coupled in parallel at the in-phase input end of frequency comparator 114 with reference to ground between, wherein said reset switch 13 further comprises control terminal, and described control terminal is coupled to the lead-out terminal receive clock signal CLK of frequency comparator 114.When clock signal clk is low level, reset switch 13 is disconnected, then charging current source 11 gives charging capacitor 12 chargings, the voltage linear at charging capacitor 12 two ends increases, when it increased to the magnitude of voltage of frequency reference signal Vfr of frequency comparator 114 inverting inputs, the clock signal clk of frequency comparator 114 outputs became high level.Correspondingly, reset switch 13 is closed.So charging capacitor 12 is pulled to ground, the voltage at its two ends is reset to rapidly zero, and namely the voltage of frequency comparator 114 in-phase input ends is reset to zero.Subsequently, clock signal clk becomes low level, reset switch 13 is disconnected, charging current source 11 restarts to charging capacitor 12 charging, until charging capacitor 12 both end voltage again reach frequency comparator 114 inverting inputs frequency reference signal Vfr magnitude of voltage and trigger clock signal clk and become high level.Sawtooth generator 115 and frequency comparator 114 are worked as previously mentioned again and again, thereby produce periodically variable sawtooth signal Vsw and clock signal clk.The timing waveform schematic diagram of clock signal clk, sawtooth signal Vsw, frequency reference signal Vfr and output voltage V o is referring to Fig. 3.
Preferably, described rectification unit 103 comprises the rectifier circuit that is comprised of four diodes.
Preferably, described feedback component comprises photoelectrical coupler.
Preferably, greater than threshold voltage Vth, when namely voltage comparison signal was high level, the 3rd terminal of selector switch 113 was connected to its first terminal in feedback voltage Vfb, so that frequency reference signal Vfr is first frequency signal Vf1; Less than threshold voltage Vth, when namely voltage comparison signal was low level, the 3rd terminal of selector switch 113 was connected to its second terminal in feedback voltage Vfb, so that frequency reference signal Vfr is second frequency signal Vf2.
Preferably, first frequency signal Vf1 is greater than second frequency signal Vf2.
When the switch flyback switch circuit 100 normal operation of switching frequency saltus step, when clock signal clk output high level signal, then the switching drive signal of control and drive circuit 116 output is controlled power switch 105 conductings of former limit, input voltage vin via the former limit winding 104-1 of rectification unit 103, transformer and former limit power switch 105 to former limit with reference to ground.Former limit winding 104-1 begins stored energy.
When the load of the switch flyback switch circuit 100 of switching frequency saltus step is relatively heavier, output voltage V o less, then also less of feedback voltage Vfb.Feedback voltage Vfb is less than threshold voltage Vth at this moment, and the voltage comparison signal of voltage comparator 112 outputs is low level.Then the 3rd terminal of selector switch 113 is connected to its second terminal, and this moment, frequency reference signal Vfr was second frequency signal Vf2.Namely under heavy condition, the magnitude of voltage of frequency reference signal Vfr is less.Sawtooth signal Vsw can early reach its peak value, and makes clock signal clk be converted to earlier high level, has dwindled the cycle of clock signal clk, and also namely the switching frequency of this moment is higher.As shown in Figure 3, the cycle of clock signal clk is T2 at this moment.
When the load of the switch flyback switch circuit 100 of switching frequency saltus step was relatively light, output voltage V o was relatively large, and then feedback voltage Vfb is also relatively large.Feedback voltage Vfb is greater than threshold voltage Vth at this moment, and the voltage comparison signal of voltage comparator 112 outputs is high level.Then the 3rd terminal of selector switch 113 is connected to its first terminal, and this moment, frequency reference signal Vfr was first frequency signal Vf1.Namely under light condition, the magnitude of voltage of frequency reference signal Vfr is larger.Sawtooth signal Vsw reaches its peak value more lately, and makes clock signal clk be converted to high level more lately, has prolonged the cycle of clock signal clk, and also namely the switching frequency of this moment is lower.As shown in Figure 3, the cycle of clock signal clk is T1 at this moment.T2＜T1 as seen from Figure 3, corresponding, the switching frequency of switch flyback switch circuit 100 under heavy condition of switching frequency saltus step is greater than its switching frequency under light condition.
Therefore the switch flyback switch circuit 100 of switching frequency saltus step is under light condition, and switching frequency is reduced, and has therefore reduced the loss under its light condition.
The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (6)
1. the switch flyback switch circuit of a switching frequency saltus step is characterized in that, comprising:
Input port receives input voltage;
Output port provides output voltage;
Rectification unit is coupled to input port and receives input voltage, produces commutating voltage;
Transformer comprises former limit winding and secondary winding, and its limit, Central Plains winding and secondary winding respectively have the first terminal and the second terminal, and the first terminal of former limit winding is coupled to rectification unit and receives commutating voltage, and the second terminal of secondary winding connects secondary with reference to ground;
Former limit power switch is coupled in the second terminal of former limit winding and former limit with reference between the ground;
The secondary diode is coupled between the first terminal and output port of secondary winding;
Output capacitor is coupled in output port and secondary with reference between the ground;
Feedback component comprises secondary part and former limit part;
Secondary contact resistance, Zener diode and former limit contact resistance, wherein the secondary part of feedback component, secondary contact resistance and Zener diode are coupled in series in output port and secondary with reference between the ground, to produce feedback voltage in the former limit of feedback component part;
Voltage comparator, have in-phase input end, inverting input and lead-out terminal, its in-phase input end threshold level voltage, its inverting input is coupled to former limit with reference to ground via former limit part and the former limit contact resistance of feedback component, to receive feedback voltage, its lead-out terminal produces voltage comparison signal;
Selector switch, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples the first frequency signal, its second terminal couples the second frequency signal, its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator, and its 3rd terminal provides frequency reference signal according to voltage comparison signal;
Frequency comparator has in-phase input end, inverting input and lead-out terminal, and its inverting input is coupled to the 3rd terminal receive frequency reference signal of selector switch, and its lead-out terminal provides clock signal;
Sawtooth generator is coupled to the lead-out terminal receive clock signal of frequency comparator, and provides the in-phase input end of sawtooth signal to frequency comparator based on clock signal;
Control and drive circuit are coupled to the lead-out terminal receive clock signal of frequency comparator, and based on clock signal, produce switching drive signal, to control the break-make of former limit power switch.
2. the switch flyback switch circuit of switching frequency saltus step as claimed in claim 1 is characterized in that, wherein
When feedback voltage greater than threshold voltage, the 3rd terminal of described selector switch is connected to its first terminal, so that the inverting input of frequency comparator receives the first frequency signal;
When feedback voltage less than threshold voltage, the 3rd terminal of described selector switch is connected to its second terminal, so that the inverting input of frequency comparator receives the second frequency signal.
3. the switch flyback switch circuit of switching frequency saltus step as claimed in claim 1 is characterized in that, wherein said first frequency signal is greater than the second frequency signal.
4. the switch flyback switch circuit of switching frequency saltus step as claimed in claim 1 is characterized in that, described feedback component comprises photoelectrical coupler.
5. the switch flyback switch circuit of switching frequency saltus step as claimed in claim 1 is characterized in that, described sawtooth generator comprises:
Charging current source, charging capacitor and reset switch, three's coupled in parallel at the in-phase input end of frequency comparator with reference to ground between, wherein
Described reset switch further comprises control terminal, and described control terminal is coupled to the lead-out terminal receive clock signal of frequency comparator.
6. the switch flyback switch circuit of switching frequency saltus step as claimed in claim 1 is characterized in that, described rectification unit comprises the rectifier circuit that is comprised of four diodes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201210568123 CN103078512A (en) | 2012-12-12 | 2012-12-12 | Flyback switch circuit of switch frequency hopping |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201210568123 CN103078512A (en) | 2012-12-12 | 2012-12-12 | Flyback switch circuit of switch frequency hopping |
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| CN103078512A true CN103078512A (en) | 2013-05-01 |
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| CN 201210568123 Pending CN103078512A (en) | 2012-12-12 | 2012-12-12 | Flyback switch circuit of switch frequency hopping |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236780A (en) * | 2013-05-03 | 2013-08-07 | 顾选祥 | PWM (pulse-width modulation) module capable of alternatively generating interruption mode and critical mode in flyback topology |
| CN105471288A (en) * | 2015-12-25 | 2016-04-06 | 青岛北斗星云通信科技有限公司 | Electronic meter apparatus |
| CN105471287A (en) * | 2015-12-25 | 2016-04-06 | 青岛北斗星云通信科技有限公司 | Electronic metering device |
| CN105490547A (en) * | 2015-12-25 | 2016-04-13 | 青岛朝阳华泰管理咨询服务有限公司 | Full-automatic milk powder making machine |
| CN105529806A (en) * | 2015-12-25 | 2016-04-27 | 青岛海特新蓝生物科技有限公司 | Multi-redundant power generation equipment |
| CN105559601A (en) * | 2015-12-20 | 2016-05-11 | 青岛海特新蓝生物科技有限公司 | Full-automatic milk powder brewing machine |
| CN105871214A (en) * | 2015-02-10 | 2016-08-17 | 英飞凌科技奥地利有限公司 | System and method for secondary-side power regulation |
-
2012
- 2012-12-12 CN CN 201210568123 patent/CN103078512A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236780A (en) * | 2013-05-03 | 2013-08-07 | 顾选祥 | PWM (pulse-width modulation) module capable of alternatively generating interruption mode and critical mode in flyback topology |
| CN105871214A (en) * | 2015-02-10 | 2016-08-17 | 英飞凌科技奥地利有限公司 | System and method for secondary-side power regulation |
| CN105871214B (en) * | 2015-02-10 | 2019-06-14 | 英飞凌科技奥地利有限公司 | System and method for primary side power regulation |
| CN105559601A (en) * | 2015-12-20 | 2016-05-11 | 青岛海特新蓝生物科技有限公司 | Full-automatic milk powder brewing machine |
| CN105471288A (en) * | 2015-12-25 | 2016-04-06 | 青岛北斗星云通信科技有限公司 | Electronic meter apparatus |
| CN105471287A (en) * | 2015-12-25 | 2016-04-06 | 青岛北斗星云通信科技有限公司 | Electronic metering device |
| CN105490547A (en) * | 2015-12-25 | 2016-04-13 | 青岛朝阳华泰管理咨询服务有限公司 | Full-automatic milk powder making machine |
| CN105529806A (en) * | 2015-12-25 | 2016-04-27 | 青岛海特新蓝生物科技有限公司 | Multi-redundant power generation equipment |
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Addressee: Lianmeng Electronic Instrument Co., Ltd. Document name: Notification that Application Deemed to be Withdrawn |
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20130501 |