CN106787637A - The self closing device and method of a kind of PWM switching power circuits - Google Patents
The self closing device and method of a kind of PWM switching power circuits Download PDFInfo
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- CN106787637A CN106787637A CN201710036544.7A CN201710036544A CN106787637A CN 106787637 A CN106787637 A CN 106787637A CN 201710036544 A CN201710036544 A CN 201710036544A CN 106787637 A CN106787637 A CN 106787637A
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- switching power
- pwm switching
- power circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- Dc-Dc Converters (AREA)
Abstract
The invention discloses the self closing device and method of a kind of PWM switching power circuits, the method includes：Obtain the work period of PWM switching power circuits；Judge the operating current of PWM switching power circuits whether less than default current threshold by the work period；When the result for judging is to be, PWM switching power circuits are closed.Through the above way, the present invention can detect the operating current of PWM switching power circuits while relatively low cost and guarantee power output is ensured, to realize being automatically switched off the purpose of PWM switching power circuits.
Description
Technical field
The present invention relates to PWM switching power circuit technical fields, particularly a kind of switching power circuit of PWM controls from
Dynamic shutoff device and method.
Background technology
In the Switching Power Supply circuit design of many electronic equipments, it is necessary to automatic detection in battery charges application
The reduction situation of circuit operating current, when operating current is reduced to certain, it is necessary to turn off operating circuit, to optimize system work(
Consumption, improves reliability.
The automatic detection circuit of prior art is typically to take the small valued resistor of a precision to be connected in current supply circuit,
Then the voltage at the resistance two ends is measured, to reach the purpose of measurement electric current.
The detection method of prior art has two shortcomings, and one is expensive precision resistance, increased product cost, and two are
Resistant series point have fallen the voltage of output in current supply circuit, really reduce power output, reduce the effect of whole system
Rate.
The content of the invention
The present invention solves the technical problem of the self closing device and side that provide a kind of PWM switching power circuits
Method, can detect the operating current of PWM switching power circuits while relatively low cost and guarantee power output is ensured, with
Realization is automatically switched off the purpose of PWM switching power circuits.
In order to solve the above technical problems, one aspect of the present invention is：A kind of PWM switching power circuits are provided
Automatic closing method, method comprises the following steps：Obtain the work period of the PWM switching power circuits；By the work
Judge the operating current of the PWM switching power circuits whether less than default current threshold as the cycle；In the result for judging
During to be, the PWM switching power circuits are closed.
Wherein, methods described also includes：
The result for judging as it is no when, the PWM switching power circuits work on.
Wherein, the T that the work period rises including output voltageonThe T that period and output voltage declineoffPeriod；
The step of work period of the acquisition PWM switching power circuits, includes：
Obtain the T in the work period of the PWM switching power circuitsoffPeriod；
Whether the operating current that the PWM switching power circuits are judged by the work period is less than default
The step of current threshold, includes：
By the T of the work periodoffPeriod judges whether the operating current of the PWM switching power circuits is less than
Default current threshold.
Wherein, the operating current IOUTWith the ToffThe relation of period is as follows：
Wherein, the COUTIt is output capacitance, Δ V is output voltage variable quantity.
Wherein, the T by the work periodoffPeriod judges the operating current of the PWM switching power circuits
Whether the step of less than default current threshold, includes：
Judge the ToffWhether the duration of period is more than default period threshold, and when the result for judging is to be, judges
For the operating current of the PWM switching power circuits is less than default current threshold.
In order to solve the above technical problems, another technical solution used in the present invention is：A kind of PWM switching power circuits
Self closing device, the device includes：
Acquisition module, the work period for obtaining the PWM switching power circuits；
Judge module, for judged by the work period PWM switching power circuits operating current whether
Less than default current threshold；
Control module, during for the result that judges in the judge module to be, closes the PWM switching power circuits.
Wherein, the control module the result that the judge module judges as it is no when, control the PWM switch power supplies
Road works on.
Wherein, the T that the work period rises including output voltageonThe T that period and output voltage declineoffPeriod；
The acquisition module is specifically the T in the work period for obtaining the PWM switching power circuitsoffPeriod；
The judge module particular by the work period ToffPeriod judges the PWM switching power circuits
Operating current whether be less than default current threshold.
Wherein, operating current IOUTWith the ToffThe relation of period is as follows：
Wherein, the COUTIt is output capacitance, Δ V is output voltage variable quantity.
Wherein, judge module is specifically to judge the ToffWhether the duration of period is more than default period threshold, the control
Molding block is judged as that the operating current of the PWM switching power circuits is less than when the result that the judge module judges is to be
Default current threshold.
The beneficial effects of the invention are as follows：The situation of prior art is different from, the present invention provides a kind of PWM switching power circuits
Self closing device and method, the method comprises the following steps：The work period of PWM switching power circuits is obtained first, so
Whether the operating current of PWM switching power circuits is judged by the work period afterwards less than default current threshold, and is being judged
Result for be when, close PWM switching power circuits.Therefore, the present invention can ensure relatively low cost and guarantee output
The operating current of PWM switching power circuits is detected while power, to realize being automatically switched off the purpose of PWM switching power circuits.
Brief description of the drawings
Fig. 1 is a kind of flow chart of the automatic closing method of PWM switching power circuits provided in an embodiment of the present invention；
Fig. 2 is the topological structure schematic diagram of the PWM switching power circuits of the embodiment of the present invention；
Fig. 3 is the output voltage waveform of PWM switching power circuits；
Fig. 4 is a kind of structured flowchart of the self closing device of PWM switching power circuits provided in an embodiment of the present invention；
Fig. 5 is the integrated circuit structure figure of judge module shown in Fig. 4 and control module.
Specific embodiment
Fig. 1 is referred to, Fig. 1 is a kind of PWM provided in an embodiment of the present invention (Pulse Width Modulation, pulse
Width modulated) switching power circuit automatic closing method flow chart, as shown in figure 1, automatic closing method bag of the invention
Include following steps：
Step S1：Obtain the work period of PWM switching power circuits.
Step S2：Judge the operating current of PWM switching power circuits whether less than default electric current by the work period
Threshold value.
In this step, step S3 is jumped to when the result for judging is to be, the result for judging as it is no when, jump to step
S4。
Step S3：Close PWM switching power circuits.
Step S4：PWM switching power circuits work on.
Also referring to Fig. 2, Fig. 2 is the boost topology schematic diagram of the PWM switching power circuits of the embodiment of the present invention.
As shown in Fig. 2 PWM switching power circuits include switch S1 and S2, inductance L, output capacitance COUTAnd load R.Wherein inductance L
One end connect the input of PWM switching power circuits, one end of other end difference connecting valve S1 and S2.Switch S1's is another
End ground connection, switchs the other end connection output capacitance C of S2OUTOne end and load R one end.Output capacitance COUTWith load R's
The other end is grounded.
In PWM switching power circuit normal works, if switch S1 closures, switch S2 disconnects, now inductance L excitations storage
Energy.If switch S2 closures, switch S1 disconnects, now inductance L demagnetizations, to output capacitance Cout and load R transmission energy.Pass through
The negative feedback control switch S1 and S2 of chip (not shown) constantly replaces unlatching and closure to realize output voltage VOUTIt is normal
Output, now loads the operating current I of ROUTNormally.
In the operating current I of load ROUTWhen smaller, in order to reduce the power consumption of PWM switching power circuits and improve efficiency,
PWM switching power circuits will be switched after S1 and S2 alternation switches transmit certain energy for a period of time into discontinuous operation state,
Switch S1 and S2 is simultaneously closed off, and loads the operating current I of ROUTCompletely by output capacitance COUTThere is provided.Above-mentioned process is opened for PWM
The work period of powered-down source circuit, referred to as hop cycle mode of operation.Wherein, the hop cycle Working mould of PWM switching power circuits
Output voltage waveforms under formula are as shown in Figure 3.
As shown in figure 3, the work period of PWM switching power circuits includes the T that output voltage VO UT risesonPeriod and output
The T that voltage declinesoffPeriod.In TonTime period, the work of PWM switching power circuits, is output capacitance COUTCharge and for load R is carried
Power supply stream.In ToffTime period, PWM switching power circuits do not work, load current IOUTPurely by output capacitance COUTThere is provided.
Then step S1 is specifically the T in the work period for obtaining PWM switching power circuitsoffPeriod, step S2 is specifically logical
Cross the T of work periodoffWhether the period judges the operating current of PWM switching power circuits less than default current threshold.
Further, due in ToffTime period, PWM switching power circuits do not work, load current IOUTPurely by defeated
Go out electric capacity COUTThere is provided, then load current IOUTWith output voltage variable quantity VOUTThere is following relation：
Wherein, COUTIt is output capacitance, Δ V is output voltage variable quantity.
The output capacitance C under PWM switching power circuit applicationsOUTValue be to determine, under the hop cycle mode of operation, PWM
Switching power circuit realizes that discontinuous operation, i.e. output voltage variation delta V are set by circuit by detecting output voltage variation delta V
It is fixed, therefore output capacitance COUTThere is determination to be worth with output voltage variation delta V, load the operating current I of ROUTWith ToffTime period into
Inverse ratio.That is, by detecting ToffThe size of time period can indirectly obtain operating current IOUTSize.Therefore, step
S2 more specifically judges ToffWhether the duration of period is more than default period threshold, and when the result for judging is to be, be judged as
The operating current of PWM switching power circuits is less than default current threshold.Shutdown signal is then produced, by whole PWM Switching Power Supplies
Circuit is closed.
The embodiment of the present invention additionally provides a kind of self closing device of PWM switching power circuits, the self closing device
Suitable for previously described method.Specifically refer to shown in Fig. 4 and Fig. 5.
Fig. 4 is a kind of structured flowchart of the self closing device of PWM switching power circuits provided in an embodiment of the present invention.Such as
Shown in Fig. 4, the device 40 includes acquisition module 41, judge module 42 and control module 43.Wherein, acquisition module 41 is used to obtain
Take the work period of PWM switching power circuits.Judge module 42 is used to judge PWM switching power circuits by the work period
Whether operating current is less than default current threshold.Control module 43 is used to, when the result that judge module 42 judges is to be, close
Close PWM switching power circuits, the result that judge module 42 judges as it is no when, control PWM switching power circuits work on.
As mentioned before with shown in Fig. 2 and Fig. 3, the work period of PWM switching power circuits 40 rises including output voltage
TonThe T that period and output voltage declineoffPeriod.In TonTime period, PWM switching power circuits 40 work, and are output capacitance
COUTCharge and for load R provides electric current.In ToffTime period, PWM switching power circuits 40 do not work, load current IOUTPurely
By output capacitance COUTThere is provided.
Then acquisition module 41 is specifically the T in the work period for obtaining PWM switching power circuitsoffPeriod.
Judge module 42 particular by the work period ToffPeriod judges the operating current of PWM switching power circuits
Whether default current threshold is less than.
Further, due in ToffTime period, PWM switching power circuits 40 do not work, load current IOUTPurely by
Output capacitance COUTThere is provided, then operating current IOUTAnd ToffThe relation of period is as follows：
Wherein, COUTIt is output capacitance, Δ V is output voltage variable quantity.
The output capacitance C under PWM switching power circuit applicationsOUTValue be to determine, under the hop cycle mode of operation, PWM
Switching power circuit realizes that discontinuous operation, i.e. output voltage variation delta V are set by circuit by detecting output voltage variation delta V
It is fixed, therefore output capacitance COUTThere is determination to be worth with output voltage variation delta V, load the operating current I of ROUTWith ToffTime period into
Inverse ratio.That is, by detecting ToffThe size of time period can indirectly obtain operating current IOUTSize.Therefore, judge
Module 42 is specifically to judge ToffWhether the duration of period is more than default period threshold, and control module 43 is sentenced in judge module 42
Disconnected result is then produced and closes letter when being, to be judged as the operating current of PWM switching power circuits less than default current threshold
Number, whole PWM switching power circuits are closed.
In actual applications, judge module 42 and control module 43 can be integrated in a timer, as shown in figure 5,
Timer 50 has two inputs and an output end, and two of which input receives T respectivelyoffThe duration of period and default
Two signals of period threshold CLK, output end output close PWM switching power circuits control signal or control PWM switch
The control signal that power circuit works on.
In sum, the present invention is to detect PWM switch power supplies by detecting the work period of PWM switching power circuits
Whether whether the working condition on road, to judge its operating current less than default current threshold, i.e., reach low current pattern, and
Circuit is automatically switched off when the result for judging is to be.Simple structure of the invention, and required cost is relatively low, without the need for outer
Detection resistance is connect, the power output of circuit is ensure that.
Embodiments of the invention are the foregoing is only, the scope of the claims of the invention is not thereby limited, it is every to utilize this hair
Equivalent structure or equivalent flow conversion that bright specification and accompanying drawing content are made, or directly or indirectly it is used in other related skills
Art field, is included within the scope of the present invention.
Claims (10)
1. a kind of automatic closing method of PWM switching power circuits, it is characterised in that methods described includes：
Obtain the work period of the PWM switching power circuits；
Judge the operating current of the PWM switching power circuits whether less than default current threshold by the work period
Value；
When the result for judging is to be, the PWM switching power circuits are closed.
2. automatic closing method according to claim 1, it is characterised in that methods described also includes：
The result for judging as it is no when, the PWM switching power circuits work on.
3. automatic closing method according to claim 1, it is characterised in that the work period includes that output voltage rises
TonThe T that period and output voltage declineoffPeriod；
The step of work period of the acquisition PWM switching power circuits, includes：
Obtain the T in the work period of the PWM switching power circuitsoffPeriod；
Whether the operating current that the PWM switching power circuits are judged by the work period is less than default electric current
The step of threshold value, includes：
By the T of the work periodoffWhether the period judges the operating current of the PWM switching power circuits less than default
Current threshold.
4. automatic closing method according to claim 3, it is characterised in that the operating current IOUTWith the ToffPeriod
Relation it is as follows：
Wherein, the COUTIt is output capacitance, Δ V is output voltage variable quantity.
5. automatic closing method according to claim 4, it is characterised in that the T by the work periodoffWhen
The step of whether section is to judge the operating current of the PWM switching power circuits less than default current threshold includes：
Judge the ToffWhether the duration of period is more than default period threshold, and when the result for judging is to be, be judged as institute
The operating current for stating PWM switching power circuits is less than default current threshold.
6. a kind of self closing device of PWM switching power circuits, it is characterised in that described device includes：
Acquisition module, the work period for obtaining the PWM switching power circuits；
Whether judge module, the operating current for being judged the PWM switching power circuits by the work period is less than
Default current threshold；
Control module, during for the result that judges in the judge module to be, closes the PWM switching power circuits.
7. self closing device according to claim 6, it is characterised in that the control module is sentenced in the judge module
When disconnected result is no, the PWM switching power circuits are controlled to work on.
8. self closing device according to claim 6, it is characterised in that the work period includes that output voltage rises
TonThe T that period and output voltage declineoffPeriod；
The acquisition module is specifically the T in the work period for obtaining the PWM switching power circuitsoffPeriod；
The judge module particular by the work period ToffPeriod judges the work of the PWM switching power circuits
Whether make electric current less than default current threshold.
9. self closing device according to claim 8, it is characterised in that the operating current IOUTWith the ToffPeriod
Relation it is as follows：
Wherein, the COUTIt is output capacitance, Δ V is output voltage variable quantity.
10. self closing device according to claim 9, it is characterised in that the judge module is specifically to judge described
ToffWhether the duration of period is more than default period threshold, and the control module is yes in the result that the judge module judges
When, it is judged as that the operating current of the PWM switching power circuits is less than default current threshold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710036544.7A CN106787637B (en) | 2017-01-18 | 2017-01-18 | Automatic closing device and method for PWM switching power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710036544.7A CN106787637B (en) | 2017-01-18 | 2017-01-18 | Automatic closing device and method for PWM switching power supply circuit |
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| Publication Number | Publication Date |
|---|---|
| CN106787637A true CN106787637A (en) | 2017-05-31 |
| CN106787637B CN106787637B (en) | 2020-05-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201710036544.7A Active CN106787637B (en) | 2017-01-18 | 2017-01-18 | Automatic closing device and method for PWM switching power supply circuit |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101667782A (en) * | 2009-09-01 | 2010-03-10 | 成都芯源系统有限公司 | Switching power supply and control method thereof |
| CN202502363U (en) * | 2011-12-27 | 2012-10-24 | Tcl显示科技（惠州）有限公司 | Automatic control device of electric iron power source |
-
2017
- 2017-01-18 CN CN201710036544.7A patent/CN106787637B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101667782A (en) * | 2009-09-01 | 2010-03-10 | 成都芯源系统有限公司 | Switching power supply and control method thereof |
| CN202502363U (en) * | 2011-12-27 | 2012-10-24 | Tcl显示科技（惠州）有限公司 | Automatic control device of electric iron power source |
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| Publication number | Publication date |
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| CN106787637B (en) | 2020-05-15 |
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