CN105763053A - On-off control circuit, on-off circuit and constant-off-time control method - Google Patents
On-off control circuit, on-off circuit and constant-off-time control method Download PDFInfo
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- CN105763053A CN105763053A CN201610339617.5A CN201610339617A CN105763053A CN 105763053 A CN105763053 A CN 105763053A CN 201610339617 A CN201610339617 A CN 201610339617A CN 105763053 A CN105763053 A CN 105763053A
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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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/1563—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators without using an external clock
-
- 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
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
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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
- H02M1/0096—Means for increasing hold-up time, i.e. the duration of time that a converter's output will remain within regulated limits following a loss of input power
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electronic Switches (AREA)
- Inverter Devices (AREA)
Abstract
The invention provides an on-off control circuit, an on-off circuit and a constant-off-time control method. When on-time of an auxiliary tube reaches constant-off-time, whether inductive current is smaller than directive current or not is detected; if the inductive current is not smaller than the directive current, the off-time of a main tube is prolonged; after the inductive current is smaller than the directive current or is smaller than a certain threshold value of the directive current, the main tube is switched on, and the auxiliary tube is switched off; when the main tube is switched on and the auxiliary tube is switched off, whether the inductive current exceeds the directive current or not is detected in real time, and if yes, the auxiliary tube is switched on, and the main tube is switched off again. The on-off control circuit, the on-off circuit and the constant-off-time control method aim at achieving voltage stabilization control over output voltage so as to achieve voltage conversion at a smaller duty ratio.
Description
Technical field
The present invention relates to technical field, particularly to a kind of ON-OFF control circuit, on-off circuit and permanent turn-off time control method.
Background technology
As it is shown in figure 1, traditional permanent turn-off time (COT, Constantofftime) control method, turn off with the constant time by controlling main switch, it is achieved convert input voltage into output voltage to drive load.In reduction voltage circuit (BUCK circuit) Fig. 1 (a), upper pipe M00 is main switch, and lower pipe M01 is fly-wheel diode or auxiliary switch pipe；In booster circuit (BOOST circuit) Fig. 1 (b), lower pipe M01 is main switch, and upper pipe M00 is fly-wheel diode or auxiliary switch pipe.
In permanent turn-off time control, after main switch conducting, when inductive current (or main switch electric current) rises to instruction current, main switch turns off, and the turn-off time controls module and controls the time that main switch shutoff is constant, now fly-wheel diode or the conducting of auxiliary switch pipe, when the turn-off time, control module timing terminated, auxiliary switch pipe turns off, and main switch turns on again, circulating with this, inductive current and instruction current waveform are as shown in Figure 2.Generally, in order to ensure main switch normally, its minimum ON time generally can be set.
Traditional scheme circuit has fairly simple, it is easy to realizes, some advantages that cost is relatively low, but is primarily present following shortcoming: 1., in permanent turn-off time control when dutycycle is smaller, dynamic response contrast is slow, as shown in Figure 3.2., owing to the shortest ON time is fixed and existed to the main switch turn-off time in permanent turn-off time control, the minimum duty cycle of on-off circuit is limited.
Summary of the invention
It is an object of the invention to provide a kind of ON-OFF control circuit, on-off circuit and permanent turn-off time control method, it is therefore intended that the voltage stabilizing realizing output voltage controls, thus realizing the voltage conversion of less dutycycle.
For solving the problems referred to above, the embodiment of the present invention provides a kind of ON-OFF control circuit, couple the supervisor of switch main circuit and auxiliary pipe, logic control circuit and current detection circuit is turned off including permanent, described current detection circuit one end couples switch main circuit, the other end couples permanent shutoff logic control circuit, described current detection circuit receives instruction current the supervisor's electric current being responsible for when turning off of sampling, being compared with supervisor's electric current by instruction current, the described permanent ON time turning off the auxiliary pipe of logic control circuit timing also controls the on off state being responsible for；
When auxiliary pipe ON time reaches constant off-time, detection inductive current, whether less than instruction current, if inductive current is not less than instruction current, then extends the turn-off time of supervisor, until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting.
As a kind of embodiment, described current detection circuit includes the first comparison circuit, described first comparison circuit one end couples switch main circuit supervisor, the other end couples permanent shutoff logic control circuit, when supervisor's conducting, supervisor electric current and instruction current are also compared by supervisor's electric current of sampling switch main circuit supervisor.
As a kind of embodiment, described first comparison circuit includes the first comparator and the first current sampling circuit, described first current sampling circuit couples supervisor, the positive input terminal of described first comparator couples described first current sampling circuit, for receiving the signal being responsible for electric current during supervisor's conducting, negative input end receives the signal of instruction current, and outfan couples permanent shutoff logic control circuit.
As a kind of embodiment, described current detection circuit includes the second comparison circuit, described second comparison circuit one end couples the auxiliary pipe of switch main circuit, the other end couples permanent shutoff logic control circuit, when auxiliary pipe turns on, auxiliary tube current and instruction current are also compared by the auxiliary tube current of the auxiliary pipe of sampling switch main circuit.
As a kind of embodiment, described second comparison circuit includes the second comparator and the second current sampling circuit, described second current sampling circuit couples auxiliary pipe, the positive input terminal of described second comparator receives instruction current, negative input end couples the second current sampling circuit, auxiliary tube current when turning on for the auxiliary pipe of sampling switch main circuit, outfan couples and permanent turns off logic control circuit.
As a kind of embodiment, the described permanent logic control circuit that turns off includes:
Timing circuit, couples auxiliary pipe, for the ON time of the auxiliary pipe of timing；
Gate circuit, couples the outfan of timing circuit and the outfan of the second comparison circuit, only when timing circuit and the second comparison circuit export and be high level, is just high level；
Trigger, couples the outfan of gate circuit and the outfan of the first comparison circuit, and when gate circuit is output as high level, described trigger is set to high level；When the first comparison circuit is output as high level, described trigger is reset to low level；
Delay circuit, couples the outfan of trigger, and when trigger is output as high level, described delay circuit produces the driving signal of supervisor；When trigger is output as low level, described delay circuit produces the driving signal of auxiliary pipe.
As a kind of embodiment, described control circuit also includes drive circuit, and described drive circuit couples permanent shutoff logic control circuit and switch main circuit, is used for receiving perseverance and turns off driving signal and controlling to be responsible for the on or off with auxiliary pipe of logic control circuit.
As a kind of embodiment, described drive circuit includes the first drive circuit and the second drive circuit, described first drive circuit couples permanent shutoff logic control circuit and supervisor, for receiving the permanent on or off driving signal to control supervisor turning off logic control circuit, described second drive circuit couples permanent shutoff logic control circuit and auxiliary pipe, for receiving the permanent on or off driving the signal auxiliary pipe of control turning off logic control circuit.
As a kind of embodiment, delay circuit includes rising edge delay circuit, trailing edge delay circuit and phase inverter, described rising edge delay circuit couples the control end of described flip-flop output and supervisor, described trailing edge delay circuit couples described flip-flop output and inverter input, and the outfan of described phase inverter couples the control end of auxiliary pipe.
As a kind of embodiment, described trigger is rest-set flip-flop, and S end couples gate circuit output, and R end couples the first comparison circuit output, and Q end couples delay circuit.
As a kind of embodiment, described gate circuit is AND circuit.
As a kind of embodiment, also including the 3rd comparator, its positive input terminal receives a reference voltage, and its negative input end inputs a feedback voltage, and its outfan couples the input of current detection circuit.
As a kind of embodiment, described current detection circuit includes inductive current detection circuit, 4th comparator and the 5th comparator, described inductive current detection circuit couples the inductance of switch main circuit, for detecting the size of inductive current, described 4th comparator positive input terminal couples described inductive current detection circuit, negative input end receives instruction current, outfan couples described permanent shutoff logic control circuit, described 5th comparator positive input terminal receives instruction current, negative input end couples described inductive current detection circuit, outfan couples described permanent shutoff logic control circuit.
The present invention provides a kind of on-off circuit, including:
Switch main circuit, including supervisor and auxiliary pipe, is load supplying by controlling the duty of supervisor and auxiliary pipe；
Arbitrary above-mentioned ON-OFF control circuit, couples described switch main circuit.
The present invention provides a kind of permanent turn-off time control method, comprises the following steps:
When auxiliary pipe ON time reaches constant off-time, whether detection inductive current is less than instruction current；
If inductive current less than instruction current, does not then extend the turn-off time of supervisor；
Until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting.
As a kind of embodiment, described until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting, when also including supervisor's conducting, auxiliary pipe is turned off.
As a kind of embodiment, also include second stage, specifically include following steps:
When supervisor's conducting, when auxiliary pipe turns off, whether detection inductive current exceedes instruction current in real time, if so, then auxiliary pipe conducting, and supervisor turns off again.
The present invention having the beneficial effects that compared to prior art: by setting up the second comparison circuit, it is achieved that supervisor the turn-off time prolongation, thus improve dutycycle smaller time transient response, switch main circuit can realize less dutycycle voltage change.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of conventional switch circuit；
Fig. 2 is the oscillogram of the inductive current of conventional switch circuit and instruction current；
Fig. 3 is the oscillogram of inductive current and instruction current when load jump of conventional switch circuit；
The oscillogram of inductive current and instruction current when Fig. 4 is the load jump of on-off circuit of the present invention；
Fig. 5 is the oscillogram of conventional switch circuit and the on-off circuit of the present invention inductive current when stable state and instruction current；
Fig. 6 be the on-off circuit of the present invention realize block diagram；
Fig. 7 is the circuit diagram of the perseverance shutoff logic control circuit of the present invention.
Accompanying drawing marks: 1, the first comparison circuit；2, the second comparison circuit；3, switch main circuit；4, ON-OFF control circuit.
Detailed description of the invention
Below in conjunction with accompanying drawing, to the present invention, above-mentioned and other technical characteristic and advantage are clearly and completely described, it is clear that described embodiment is only the section Example of the present invention, rather than whole embodiment.
As shown in Figure 6, the embodiment of the present invention provides a kind of on-off circuit, including ON-OFF control circuit 4 and switch main circuit 3, ON-OFF control circuit 4 couples switch main circuit 3, and reception feedback voltage FB, sampling are responsible for the electric current of M00 and auxiliary pipe M01 and control the on off state of supervisor M00 and auxiliary pipe M01 according to instruction current.
The embodiment of the present invention provides a kind of ON-OFF control circuit 4 to include the 3rd comparator U01, current detection circuit, permanent shutoff logic control circuit U04 and drive circuit.
The positive input terminal of the 3rd comparator U01 receives a reference voltage VREF, negative input end inputs the feedback voltage FB of switch main circuit 3 divider resistance R01, a R02, outfan exports a bucking voltage VC, outfan couples the input of current detection circuit, controlled the size of inductive current by supplementary voltage VC, supplementing voltage VC is the magnitude of voltage of instruction current.
Current detection circuit includes the first comparison circuit 1 and the second comparison circuit 2, first comparison circuit 1 includes the first comparator U08 and the first current sampling circuit U07, first current sampling circuit U07 couples supervisor M00, the positive input terminal of the first comparator U08 couples described first current sampling circuit U07, negative input end couples the 3rd comparator U01 output, and outfan couples permanent shutoff logic control circuit U04；Second comparison circuit 2 includes the second comparator U03 and the second current sampling circuit U02, second current sampling circuit U02 couples auxiliary pipe M01, the positive input terminal of the second comparator U03 couples the 3rd comparator U01 output, negative input end couples the second current sampling circuit U02, and outfan couples permanent shutoff logic control circuit U04.
As another embodiment, current detection circuit includes inductive current sample circuit, the 4th comparator and the 5th comparator, inductive current sample circuit couples the inductance of switch main circuit, for directly detecting the size of inductive current, but not with in aforesaid way by detecting and the equal supervisor's electric current of inductive current and auxiliary tube current.4th comparator positive input terminal couples the output of inductive current sample circuit, and negative input end couples the 3rd comparator U01 output, and outfan couples permanent turn-on logic control circuit input.5th comparator positive input terminal couples the 3rd comparator U01 output, and negative input end couples the output of inductive current sample circuit, and outfan couples permanent turn-on logic control circuit input.Which is identical with above-mentioned current detection circuit principle, difference be in that by originally sampled by the first current sampling circuit U07 and the second current sampling circuit U02 electric current during supervisor's conducting and the conducting of auxiliary pipe time electric current obtain inductive current and become and directly sampled inductive current by inductive current sample circuit, production cost can be saved.
The permanent logic control circuit U04 that turns off includes timing circuit U10, gate circuit U11, trigger U12 and delay circuit.Timing circuit U10, couples auxiliary pipe M01, for the ON time of the auxiliary pipe M01 of timing；Gate circuit U11, adopts AND circuit, and the input of its two ends is respectively coupled to the outfan of timing circuit U10 and the outfan of the second comparison circuit 2, and only when timing circuit U10 and the second comparison circuit 2 export and be high level, its output is just high level；Trigger U12, adopt rest-set flip-flop, its S end couples gate circuit output, its R end couples the first comparison circuit 1 and exports, its Q end couples delay circuit, and when gate circuit U11 is output as high level, trigger U12 is reset to low level, when the second comparison circuit 2 is output as high level, trigger U12 is set to high level；Delay circuit, delay circuit includes rising edge delay circuit U13, trailing edge delay circuit U14 and phase inverter U15, rising edge delay circuit U13 one end couples trigger U12 outfan, the other end couples the control end of supervisor M00, trailing edge delay circuit U14 one end couples trigger U12 outfan, and the other end couples phase inverter U15 input, and the outfan of phase inverter U15 couples the control end of auxiliary pipe M01, when trigger U12 is output as high level, produce the driving signal of supervisor M00；When trigger U12 is output as low level, produce the driving signal of auxiliary pipe M01.
Drive circuit includes the first drive circuit U05 and the second drive circuit U06, first drive circuit U05 one end couples the permanent outfan turning off logic control circuit U04, the other end couples the control pole of supervisor M00, for receiving the on or off driving signal to control supervisor M00 of the permanent logic control circuit U04 of shutoff；Second drive circuit U06 one end couples permanent shutoff logic control circuit U04, and the other end couples the control pole of auxiliary pipe M01, for receiving the on or off driving the signal auxiliary pipe M01 of control of the permanent logic control circuit M14 of shutoff.
Switch main circuit 3 can be any one on-off circuit, such as Buck circuit, Boost circuit, forward converter or circuit of reversed excitation etc., no matter which kind of circuit all includes supervisor M00, auxiliary pipe M01 and inductance L00, in the permanent turn-off time controls, turn off with the constant time by controlling supervisor, it is achieved convert input voltage into output voltage to drive load.The outfan of switch main circuit 3 is provided with two divider resistances (R01, R02), and the connection node of two divider resistances exports a feedback voltage FB and is connected to the negative input end of the 3rd comparator U01.In the present embodiment, supervisor M00 is switching tube, and auxiliary pipe M01 is also switching tube.
In the present invention, illustrate with BUCK circuit.As shown in Figure 6, in the BUCK perseverance turn-off time controls, permanent shutoff logic control circuit U04 controls the first drive circuit U05 makes supervisor M00 turn off, and controls the second drive circuit U06 and makes auxiliary pipe M01 turn on, and now auxiliary pipe M01 size of current is inductive current size.The permanent shutoff auxiliary pipe M01 ON time of logic control circuit U04 timing, if the output IBOT of the second comparator U03 is just, namely auxiliary pipe M01 electric current is less than instruction current, as now the permanent auxiliary pipe M01 ON time of logic control circuit U04 timing that turns off reaches the permanent turn-off time, then auxiliary pipe M01 is turned off by the permanent logic control circuit U04 that turns off, supervisor's M00 conducting, and auxiliary pipe M01 closes to have no progeny to be needed to insert certain Dead Time, supervisor M00 is made to turn on again, it is prevented that supervisor, auxiliary pipe directly turn on ground connection；If the permanent auxiliary pipe M01 ON time of logic control circuit U04 timing that turns off is not up to the permanent turn-off time, then, etc. after the permanent turn-off time to be achieved, auxiliary pipe M01 is turned off by the permanent logic control circuit U04 of shutoff again.nullTurn off at auxiliary pipe M01，During supervisor's M00 conducting，Supervisor's M00 size of current is inductive current size，First current sampling circuit U07 is when being responsible for M00 conducting，The electric current of sampling supervisor M00，And convert that current to voltage，It is connected to the positive input terminal of the first comparator U08，Bucking voltage VC is connected to the negative input end of the first comparator U08，When being responsible for M00 current ratio instruction current and being big，When the namely output of the first current sampling circuit U07 is higher than bucking voltage VC，First comparator U08 output is positive voltage by negative voltage upset，This output voltage ITOP is connected to the permanent input turning off logic control circuit U04，Permanent shutoff logic control circuit U04 now controls the first drive circuit U05 will be responsible for M00 shutoff，Control the second drive circuit U06 to be turned on by auxiliary pipe M01.Supervisor M00 closes to have no progeny and needs to insert certain Dead Time, then makes auxiliary pipe M01 turn on, it is prevented that supervisor M00, auxiliary pipe M01 directly turn on ground connection.By the second current sampling circuit U02 of auxiliary pipe M01 and the second comparator U03, it is achieved that the prolongation of the turn-off time of supervisor M00.nullWhen auxiliary pipe M01 turns on，The electric current of the second current sampling circuit U02 auxiliary pipe M01 of sampling，And convert the current to voltage，It is connected to the negative input end of the second comparator U03，Bucking voltage VC is connected to the positive input terminal of the second comparator U03，When auxiliary pipe M01 turns on，When the permanent shutoff auxiliary pipe M01 ON time of logic control circuit U04 timing reaches the permanent turn-off time，Inductive current is more than instruction current，Namely the output of the second current sampling circuit U02 is more than bucking voltage VC，Then the second comparator U03 is output as bearing，Then permanent turn off logic control circuit U04 to control the second drive circuit U06 constantly on，Until the output of the second current sampling circuit U02 is less than bucking voltage VC，Second comparator U03 is just output as，Auxiliary pipe M01 turns off，Supervisor's M00 conducting，Now the permanent logic control circuit U04 that turns off controls the first drive circuit and makes the ON time of supervisor M00 be the shortest ON time tON_min。
In the present invention, the permanent circuit implementing method turning off logic control circuit U04 is as it is shown in fig. 7, in set forth below, 1 represents high level, and 0 represents low level.When the driving signal of supervisor M00 be TDRV, TDRV is 1, the first drive circuit U05 controls supervisor's M00 conducting；The driving signal of auxiliary pipe M01 is BDRV, BDRV when being 1, and the second drive circuit U06 controls auxiliary pipe M01 conducting.When BDRV is 1, auxiliary pipe M01 turns on, and timing circuit U10 is output as 0, the ON time of the auxiliary pipe M01 of timing circuit U10 timing, and when timing to permanent turn-off time, then it is output as 1.The output of timing circuit U10 and IBOT signal are and the input of door U11 that when two inputs of AND circuit U11 are all 1, then it is output as 1, and otherwise it is output as 0.Namely auxiliary pipe M01 electric current is 1 less than instruction current and auxiliary pipe M01 ON time more than the output signal ON of permanent turn-off time then AND circuit U11, and otherwise ON is 0.ON is signally attached to the S end of rest-set flip-flop U12, set (SET) outfan Q, and when namely ON signal is 1, then output Q is set to 1；ITOP is signally attached to the R end of rest-set flip-flop U12, and reset (RESET) outfan Q, and when namely ITOP signal is 1, then output Q is reset to 0.When the output Q of rest-set flip-flop U12 is 1, through rising edge delay circuit U13, produce supervisor M00 and drive signal TDRV, rising edge Inserted delay Dead Time, it is prevented that supervisor M00 and auxiliary pipe M01 directly turns on；When the output Q of rest-set flip-flop U12 is 0, through trailing edge delay circuit U14 and phase inverter U15, produce auxiliary pipe M01 and drive signal BDRV, trailing edge Inserted delay Dead Time, it is prevented that supervisor M00 and auxiliary pipe M01 directly turns on.
As shown in Figure 4, in permanent turn-off time control, when on-off circuit steady operation, turn-off time control circuit controls the supervisor M00 in on-off circuit with constant turn-off time TOFFTurn off.When on-off circuit dynamic response, such as load jump etc., instruction current reduces suddenly, if in a constant off-time, the inductive current that current sample module obtains is more than the size of instruction current, the turn-off time then allowing supervisor extends, until inductive current is less than instruction current or less than, after the certain threshold value of instruction current, just allowing supervisor's M00 conducting.
As shown in Figure 5, in permanent turn-off time control, owing to supervisor M00 has a minimum ON time, and its turn-off time is constant, therefore the dutycycle of on-off circuit is limited, now, output voltage is higher than the output voltage values set, therefore instruction current reduces, and inductive current does not reach instruction current, and output voltage cannot by voltage stabilizing to the output voltage values set.If not reaching instruction current at a constant off-time internal inductance electric current, the turn-off time of supervisor M00 is allowed to extend, until inductive current reaches instruction current or lower than after the certain threshold value of instruction current, just allow supervisor's M00 conducting, the voltage stabilizing realizing output voltage controls, thus realizing the voltage conversion of less dutycycle.
The embodiment of the present invention provides a kind of permanent turn-off time control method, comprises the following steps,
First stage: when auxiliary pipe ON time reaches constant off-time, whether detection inductive current reaches instruction current；If inductive current less than instruction current, does not then extend the turn-off time of supervisor；Until inductive current is less than instruction current or less than after the certain threshold value of instruction current, being then responsible for conducting, auxiliary pipe turns off.
Second stage: when supervisor's conducting, when auxiliary pipe turns off, whether detection inductive current exceedes instruction current in real time, if then auxiliary pipe conducting, supervisor turns off again.
Particular embodiments described above, has carried out further detailed description to the purpose of the present invention, technical scheme and beneficial effect, it will be appreciated that the foregoing is only specific embodiments of the invention, the protection domain being not intended to limit the present invention.Particularly point out, to those skilled in the art, all within the spirit and principles in the present invention, any amendment of making, equivalent replacement, improvement etc., should be included within protection scope of the present invention.
Claims (17)
1. an ON-OFF control circuit, it is characterized in that, couple the supervisor of switch main circuit and auxiliary pipe, logic control circuit and current detection circuit is turned off including permanent, described current detection circuit one end couples switch main circuit, the other end couples permanent shutoff logic control circuit, described current detection circuit receives instruction current the supervisor's electric current being responsible for when turning off of sampling, being compared with supervisor's electric current by instruction current, the described permanent ON time turning off the auxiliary pipe of logic control circuit timing also controls the on off state being responsible for；
When auxiliary pipe ON time reaches constant off-time, detection inductive current, whether less than instruction current, if inductive current is not less than instruction current, then extends the turn-off time of supervisor, until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting.
2. ON-OFF control circuit according to claim 1, it is characterized in that, described current detection circuit includes the first comparison circuit, described first comparison circuit one end couples switch main circuit supervisor, the other end couples permanent shutoff logic control circuit, when supervisor's conducting, supervisor electric current and instruction current are also compared by supervisor's electric current of sampling switch main circuit supervisor.
3. ON-OFF control circuit according to claim 2, it is characterized in that, described first comparison circuit includes the first comparator and the first current sampling circuit, described first current sampling circuit couples supervisor, the positive input terminal of described first comparator couples described first current sampling circuit, for receiving the signal being responsible for electric current during supervisor's conducting, negative input end receives the signal of instruction current, and outfan couples perseverance and turns off logic control circuit.
4. ON-OFF control circuit according to claim 2, it is characterized in that, described current detection circuit includes the second comparison circuit, described second comparison circuit one end couples the auxiliary pipe of switch main circuit, the other end couples permanent shutoff logic control circuit, when auxiliary pipe turns on, auxiliary tube current and instruction current are also compared by the auxiliary tube current of the auxiliary pipe of sampling switch main circuit.
5. ON-OFF control circuit according to claim 4, it is characterized in that, described second comparison circuit includes the second comparator and the second current sampling circuit, described second current sampling circuit couples auxiliary pipe, the positive input terminal of described second comparator receives instruction current, negative input end couples the second current sampling circuit, auxiliary tube current when turning on for the auxiliary pipe of sampling switch main circuit, and outfan couples and permanent turns off logic control circuit.
6. ON-OFF control circuit according to claim 4, it is characterised in that the described permanent logic control circuit that turns off includes:
Timing circuit, couples auxiliary pipe, for the ON time of the auxiliary pipe of timing；
Gate circuit, couples the outfan of timing circuit and the outfan of the second comparison circuit, only when timing circuit and the second comparison circuit export and be high level, is just high level；
Trigger, couples the outfan of gate circuit and the outfan of the first comparison circuit, and when gate circuit is output as high level, described trigger is set to high level；When the first comparison circuit is output as high level, described trigger is reset to low level；
Delay circuit, couples the outfan of trigger, and when trigger is output as high level, described delay circuit produces the driving signal of supervisor；When trigger is output as low level, described delay circuit produces the driving signal of auxiliary pipe.
7. ON-OFF control circuit according to claim 6, it is characterized in that, also including drive circuit, described drive circuit couples permanent shutoff logic control circuit and switch main circuit, is used for receiving driving signal and controlling to be responsible for the on or off with auxiliary pipe of permanent shutoff logic control circuit.
8. ON-OFF control circuit according to claim 7, it is characterized in that, described drive circuit includes the first drive circuit and the second drive circuit, described first drive circuit couples permanent shutoff logic control circuit and supervisor, for receiving the permanent on or off driving signal to control supervisor turning off logic control circuit, described second drive circuit couples permanent shutoff logic control circuit and auxiliary pipe, for receiving the permanent on or off driving the signal auxiliary pipe of control turning off logic control circuit.
9. ON-OFF control circuit according to claim 6, it is characterized in that, delay circuit includes rising edge delay circuit, trailing edge delay circuit and phase inverter, described rising edge delay circuit couples the control end of described flip-flop output and supervisor, described trailing edge delay circuit couples described flip-flop output and inverter input, and the outfan of described phase inverter couples the control end of auxiliary pipe.
10. ON-OFF control circuit according to claim 6, it is characterised in that described trigger is rest-set flip-flop, S end couples gate circuit output, and R end couples the first comparison circuit output, and Q end couples delay circuit.
11. ON-OFF control circuit according to claim 6, it is characterised in that described gate circuit is AND circuit.
12. ON-OFF control circuit according to claim 1, it is characterised in that also include the 3rd comparator, its positive input terminal receives a reference voltage, and its negative input end inputs a feedback voltage, and its outfan couples the input of current detection circuit.
13. ON-OFF control circuit according to claim 1, it is characterized in that, described current detection circuit includes inductive current detection circuit, 4th comparator and the 5th comparator, described inductive current detection circuit couples the inductance of switch main circuit, for detecting the size of inductive current, described 4th comparator positive input terminal couples described inductive current detection circuit, negative input end receives instruction current, outfan couples described permanent shutoff logic control circuit, described 5th comparator positive input terminal receives instruction current, negative input end couples described inductive current detection circuit, outfan couples described permanent shutoff logic control circuit.
14. an on-off circuit, it is characterised in that including:
Switch main circuit, including supervisor and auxiliary pipe, is load supplying by controlling the duty of supervisor and auxiliary pipe；
The arbitrary described ON-OFF control circuit of claim 1-13, couples described switch main circuit.
15. a permanent turn-off time control method, it is characterised in that comprise the following steps:
When auxiliary pipe ON time reaches constant off-time, whether detection inductive current is less than instruction current；
If inductive current less than instruction current, does not then extend the turn-off time of supervisor；
Until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting.
16. permanent turn-off time control method according to claim 15, it is characterised in that described until inductive current less than instruction current or less than after the certain threshold value of instruction current, is then responsible for conducting, when also including supervisor's conducting, auxiliary pipe is turned off.
17. permanent turn-off time control method according to claim 16, it is characterised in that also include second stage, specifically include following steps:
When supervisor's conducting, when auxiliary pipe turns off, whether detection inductive current exceedes instruction current in real time, if so, then auxiliary pipe conducting, and supervisor turns off again.
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| CN201610339617.5A CN105763053B (en) | 2016-05-19 | 2016-05-19 | ON-OFF control circuit, switching circuit and permanent turn-off time control method |
| US15/597,500 US10205448B2 (en) | 2016-05-19 | 2017-05-17 | Switch control circuit and switch circuit |
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