CN105553265B - Control circuit for switching type DCDC converter - Google Patents
Control circuit for switching type DCDC converter Download PDFInfo
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- CN105553265B CN105553265B CN201511028529.5A CN201511028529A CN105553265B CN 105553265 B CN105553265 B CN 105553265B CN 201511028529 A CN201511028529 A CN 201511028529A CN 105553265 B CN105553265 B CN 105553265B
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Classifications
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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
- H02M3/158—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 including plural semiconductor devices as final control devices for a single load
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- Dc-Dc Converters (AREA)
Abstract
Disclosed is a control circuit for a switching type DCDC converter, including: a conduction signal generating circuit having a first input terminal, a second input terminal, and an output terminal, and providing a conduction signal at its output terminal based on a comparison result of a reference signal and a feedback signal, wherein the feedback signal reflects a load current or an output voltage of the converter; the turn-off signal generating circuit comprises a first reset circuit, a first switch, a first capacitor, a first current control circuit and a first comparator, wherein the output end of the turn-off signal generating circuit provides a turn-off signal to turn off a switching tube of the converter; and the logic circuit is provided with a first input end, a second input end and an output end, and provides a switching signal at the output end based on the on signal and the off signal so as to control the on and off of the switching tube. The control circuit may make the switching frequency of the switching-type DCDC converter substantially constant.
Description
Technical field
The embodiment of the present invention is related to electronic circuit, and the more specific one kind that is still not exclusively to is used for switching mode DC-
The control circuit of DC converters.
Background technology
DC-DC converter is a kind of electronic device receiving DC input voltages and DC output voltage is provided to load.DC-DC
Converter be typically configured to based on some the unadjusted sources DC voltages to load provide adjusted DC output voltage or
Electric current (" load voltage " or " load current ").Such as (wherein battery, which provides, has 12 volts of approximation in many automobile applications
The DC power sources of special unadjusted voltage), DC-DC converter can be used for receiving unadjusted 12 volts of DC as source voltage simultaneously
Adjusted DC output voltage or electric current are provided with drive in vehicle various electronic circuits (instrument, attachment, engine control,
Lighting apparatus, radio/stereo etc.).DC output voltage can, higher or identical lower than the source voltage from battery.
In another example in some illumination applications, DC-DC converter can be used for receiving unadjusted 12 volts of DC as source voltage and carrying
For adjusted DC output current to drive LED.
Be commonly used in DC-DC converter control technology have Average Current Control technology, peak value comparison method technology and
Fixed turn-on time (COT) control technology etc..Average Current Control technology and peak value comparison method technology can make switch turn
Parallel operation obtains accurately output voltage or output current, but its loop compensation is complicated, and transient response is poor.Use COT
The dc-dc converter of control technology can not need loop compensation networks, so that circuit design is simpler, but its frequency
Rate is easy to change with input and output voltage or load current.For this purpose, how to be designed more for COT type DC-DC converters
The control circuit of optimization is so that it is the problem that those skilled in the art face that it, which keeps relative constant switching frequency,.
Invention content
To solve the above problems, a kind of control circuit for switching mode DC-DC converter, the converter has at least
One switching tube, the control circuit include：Continuity signal generation circuit has first input end, the second input terminal and output
End, the comparison result based on reference signal and feedback signal provides Continuity signal in its output end, wherein the feedback signal is anti-
Reflect the load current or output voltage of the dc-dc converter；Cut-off signals generation circuit has input terminal and output end,
Output end provides cut-off signals to turn off the switching tube；And logic circuit, there is first input end, the second input terminal and defeated
Outlet provides switching signal to control the conducting of the switching tube based on the Continuity signal and the cut-off signals in output end
And shutdown；Wherein, the cut-off signals generation circuit includes：First reset circuit has input terminal and output end, input terminal
It is coupled to the output end of the logic circuit, output end provides the first reset signal；First switch has control terminal, first
End and second end, control terminal are coupled to the first reset circuit output end, and the second termination is coupled to the first power end；First
Capacitance has a first end and a second end, and first end is coupled to the first switch first end, and second end is coupled to described
One power end；There is first current control circuit first input end and output end, first input end to be coupled to the logic electricity
For the output end on road to receive the switching signal, output end is coupled to the first end of first capacitance to provide the first electricity
Stream, frequency of first current control circuit based on the switching signal adjust first electric current with setpoint frequency so that
The frequency of the switching signal is substantially equal to setpoint frequency；And first comparator, first input end, the second input terminal and defeated
Outlet, first input end receive the first reference voltage, and the second input terminal is coupled to the first end of first capacitance, defeated
Outlet is configured to the output end of the cut-off signals generation circuit.
Control circuit provided by the invention can make switching mode DC-DC converter obtain the constant switching frequency of essence.
Description of the drawings
Examples of the present invention will be described by way of reference to the accompanying drawings, wherein：
Fig. 1 shows the circuit diagram of a dc-dc converter according to an embodiment of the invention 10；
Fig. 2 shows the circuit diagrams of the first current control circuit 200 according to an embodiment of the invention；
Fig. 3 shows the circuit diagram of the first current control circuit 300 according to an embodiment of the invention；
Fig. 4 shows the oscillogram in 300 course of work of the first current control circuit according to an embodiment of the invention；
Fig. 5 shows the circuit diagram of the first current control circuit 500 according to an embodiment of the invention.
Specific implementation mode
Specific embodiment below represents exemplary embodiment of the present invention, and substantially merely illustrative explanation rather than
Limitation.In the description, refer to that " one embodiment " or " embodiment " means to combine specific spy described in the embodiment
Sign, structure or characteristic include at least one embodiment of the present invention.Term " in one embodiment " is in the description
Each position occurs not all referring to identical embodiment, nor mutually exclusive other embodiment or various embodiments.
All features disclosed in this specification or disclosed all methods or in the process the step of, in addition to mutually exclusive feature and/
Or other than step, it can combine in any way.
The specific implementation mode that the present invention will be described in detail below with reference to the accompanying drawings.Through the identical reference numeral of all attached drawings
Indicate identical component or feature.
Fig. 1 shows the circuit diagram of a dc-dc converter according to an embodiment of the invention 10.Dc-dc converter
10 include control circuit 100 and switching circuit 110.
Switching circuit 110 uses synchronous buck transformation topology structure, including main switch M1, secondary switching tube M2, inductance
Device L and output capacitor CO.Under the action of controlling signal CTRL, switching circuit 110 by the conducting of switching tube M1 and M2 with
Shutdown, output voltage VO UT is converted to by input voltage VIN.One end of main switch M1 receives input voltage VIN, other end electricity
It is coupled to time one end of switching tube M2.The other end of secondary switching tube M2 is grounded.One end of inductor L be electrically coupled to switching tube M1 and
The connecting pin of M2, output capacitor COUT electric couplings are between the other end and ground of inductor L.The both ends output capacitor COUT
Voltage is output voltage VO UT.Switching circuit 110 can also have other various topological structures, such as non-synchronous buck converts
Topology, Boost type boost configuration and the topological structures such as normal shock or flyback.
Control circuit 100 includes Continuity signal generation circuit 101, cut-off signals generation circuit 102 and logic circuit 103.
Continuity signal generation circuit 101 has first input end, the second input terminal and output end, is based on reference signal
The comparison result of VREF and output voltage VO UT provide Continuity signal SETON in output end.In another embodiment, it is connected
The comparison result that signal generating circuit 101 is also based on the voltage signal of reference signal VREF and characterization load current IOUT exists
Output end provides Continuity signal SETON.According to one embodiment of present invention, messenger generation circuit 101 compares including second
Device CM2, the second comparator CM2 include first input end, the second input terminal and output end, are respectively configured as Continuity signal and generate electricity
The first input end on road, the second input terminal and output end.
Cut-off signals generation circuit 102, including the first reset circuit RC1, first switch S1, the first capacitance C1, the first electricity
Flow control circuit ICTL and first comparator CM1, output end provide cut-off signals SETOFF with on-off switching tube M1.
There is first reset circuit RC1 input terminal and output end, input terminal to be coupled to the output end of logic circuit 103,
Its output end provides the first reset signal RS1.First switch S1 has control terminal, first end and second end, control terminal coupling
To the first reset circuit RC1 output ends, the second termination is coupled to the first power end PT1.In one embodiment, the first power end
PT1 is being grounded.First capacitance C1, has a first end and a second end, and first end is coupled to first switch S1 first ends, the
Two ends are coupled to the first power end PT1.First current control circuit ICTL has first input end, power end and output end,
First input end is coupled to the output end of logic circuit 103 to receive switching signal CTRL, and power end is coupled to second source
PT2, output end is held to be coupled to the first end of the first capacitance C1 to provide the first electric current I1, the first current control circuit ICTL bases
Its first electric current I1 is adjusted with setpoint frequency so that the frequency of switching signal is substantially equal to set in the frequency of switching signal CTRL
Determine frequency FSET.In one embodiment, second source end PT2 is receiving input voltage VIN or internal power source voltage.The
One comparator CM1, first input end, the second input terminal and output end, first input end receive the first reference voltage VREF1,
Its second input terminal is coupled to the first end of the first capacitance C1, and output end is configured to the output of cut-off signals generation circuit 102
End.
Logic circuit 103 has first input end, the second input terminal and output end, is based on Continuity signal SETON and shutdown
Signal SETOFF provides switching signal CTRL in output end, wherein cut-off signals SETOFF is carved when off to be turned over by inactive level
Switch to significant level to turn off main switch M1.In one embodiment, logic circuit 103 includes rest-set flip-flop RS1, has the
One input terminal S is to receive Continuity signal SETON, the second input terminal R to receive cut-off signals SETOFF and output end Q, based on leading
Messenger SETON and cut-off signals SETOFF provides switching signal CTRL in output end Q.
In one embodiment, when output voltage VO UT is less than reference voltage VREF, Continuity signal generation circuit 101
The Continuity signal SETON of output is high level by low transition, and the switching signal CTRL that logic circuit 103 exports is by low level
High level is converted to open main switch M1.First reset signal RS1 of the first reset circuit RC1 outputs generates a sharp arteries and veins
Rush signal so that the first capacitance voltage VC1 is by fast setting zero, and then, the first current control circuit ICTL starts to the first electricity
Hold C1 chargings, voltage VC1 gradually rises on the first capacitance.When voltage VC1 is increased to the first reference voltage VREF1 on the first capacitance
When, the cut-off signals SETOFF of first comparator CM1 output is high level, the switch letter of logic circuit output by low transition
Number CTRL is converted to low level to turn off main switch M1 by high level.
In one embodiment, when the switching frequency of dc-dc converter 10 (i.e. the frequency of switching signal CTRL) is less than setting
When frequency FSET, the first current control circuit ICTL output currents I1 increases with on-off switching tube M1 as early as possible, that is, reduces switching tube
The turn-on time of M1, and then reduce the switch periods (switching frequency for increasing dc-dc converter 10) of dc-dc converter 10, to
So that the switching frequency of dc-dc converter 10 is substantially equal to setpoint frequency.
In one embodiment, when the switching frequency of dc-dc converter 10 (i.e. the frequency of switching signal CTRL) is more than setting
When frequency FSET, the first current control circuit ICTL output currents I1 reduces to be delayed to turn off switching tube M1, that is, increases switching tube
The turn-on time of M1, and then increase the switch periods (switching frequency for reducing dc-dc converter 10) of dc-dc converter 10, to
So that the switching frequency of dc-dc converter 10 is substantially equal to setpoint frequency.
Fig. 2 shows the circuit diagrams of a first current control circuit 200 according to an embodiment of the invention.First
Current control circuit 200 is a specific embodiment of the first current control circuit ICTL.First current control circuit 200 has
First input end receives reference clock signal CKRF and output end carrying to receive switching signal CTRL, the second input terminal
For the first electric current I1.First current control circuit 200 includes：Phase discriminator PD has first input end, the second input terminal and output
End, first input end is coupled to the first input end of the first current control circuit 200, its second input terminal is coupled to the first electricity
Second input terminal of flow control circuit 200, output end are coupled to the output end of the first current control circuit 200, phase discriminator base
Its output current is adjusted in the frequency difference of switching signal CTRL and reference clock signal CKRF.
Fig. 3 shows a first current control circuit, 300 circuit diagram according to an embodiment of the invention.First electricity
Flow control circuit 300 is a specific embodiment of the first current control circuit ICTL.First current control circuit 300 has the
One input terminal receives the second reference voltage VREF2 and output end carrying to receive switching signal CTRL, the second input terminal
For the first electric current I1.First current control circuit 300 includes：Second reset circuit RC2, third reset circuit RC3, the second electric current
Source IS2, second switch S2, the second capacitance C2, the first trsanscondutance amplifier GA1, first, which is adopted, protects switch SS1, and first adopts guarantor's capacitance
SC1, voltage-current converter circuit VIC.
There is second reset circuit RC2 input terminal and output end, input terminal to be coupled to the output end of logic circuit 103
To receive switching signal CTRL, output end provides the second reset signal RS2.Third reset circuit RC3, have input terminal with it is defeated
Outlet, input terminal are coupled to the output end of the second reset circuit RC2, and output end provides third reset signal RS3.Second electricity
Stream source IS2, has a first end and a second end, and first end is coupled to second source end PT2.Second switch S2, have control terminal,
First end and second end, control terminal are coupled to third reset circuit RC3 output ends, and first end is coupled to the second current source
IS2 second ends, the second termination are coupled to the first power end PT1.Second capacitance C2, has a first end and a second end, first end
The second current source IS2 second ends are coupled to, second end is coupled to the first power end PT1.First trsanscondutance amplifier GA1, has
First input end, the second input terminal and the first output end GO1, first input end are coupled to the first capacitance C1 first ends, the
Two input terminals receive the second reference voltage VREF2.First adopts guarantor switch SS1, has control terminal, first end and second end, control
End processed is coupled to the second reset circuit RC2 output ends to receive the second reset signal RS2, and first end is coupled to the first mutual conductance and puts
The first output end GO1 of big device GA1.First adopts guarantor capacitance SC1, has a first end and a second end, first end is coupled to first
It adopts and protects switch SS1 second ends, second end is coupled to the first power end PT1.Voltage-current converter circuit VIC has input terminal
And output end, input terminal are coupled to first and adopt guarantor's capacitance SC1 first ends, output end is coupled to the first current control circuit
300 output ends are to provide the first electric current I1.
Fig. 4 shows the waveform in a first current control circuit, 300 course of work according to an embodiment of the invention
Figure.First current control circuit 300 can be used for dc-dc converter 10 shown in FIG. 1, when output voltage VO UT is less than the first reference
When voltage VREF1, the Continuity signal SETON of the output of Continuity signal generation circuit 101 is high level, logic by low transition
Circuit 103 export switching signal CTRL by low transition be high level to open main switch M1.Main switch M1 is opened
The second reset circuit RC2 generates a sharp pulse at the first time afterwards, and the significant level (high level) of the sharp pulse is so that first adopts
It protects switch SS1 to be closed, during first adopts and protect switch SS1 closures, the first trsanscondutance amplifier GA1 is adopted by first and protected switch SS1
It is adopted to first and protects capacitance SC1 charge and discharge.The second time (was more than at the first time) third reset circuit RC3 after main switch M1 is opened
A sharp pulse is generated, the high level of the sharp pulse makes second switch S2 close, and the second capacitance C2 is put by second switch S2
Electricity.After third reset signal RS3 is converted to low level by high level, the second current source IS2 provides the second electric current I2 pairs second electricity
Hold C2 chargings, the second capacitance voltage VC2 is increased by zero, until next period third reset signal RS3 is again converted to height
Level.Wherein, it is setting time TSET to define the following time
TSET=C2 × VREF2/I2 (1)
Since the sharp pulse time of the second reset signal RS2 and third reset signal RS3 are very short, usually only more than ten
Microsecond, therefore setting time TSET is substantially equal to the switch periods of switching signal CTRL.
At steady state, as shown in period 1 P1 and P2, (T1 moment and T2 when first, which adopts, protects switch SS1 conductings
Moment), the second capacitance voltage VC2 is substantially equal to the second reference voltage VREF2, and the first trsanscondutance amplifier GA1 is not adopted to first
Protect capacitance SC1 charge and discharge, first adopts and protect voltage on capacitance SC1 and remains unchanged, when the turn-on time of dc-dc converter 10 and shutdown
Between also remain unchanged.
In one embodiment, if switch periods P3 long (being more than setting time TSET), since the second current source IS2 is held
Continuous charging adopts first and protects when switch SS1 is closed (T3 moment), and the second capacitance voltage VC2 will be more than the second reference voltage
VREF2, trsanscondutance amplifier GA1 will protect capacitance SC1 chargings to adopting, and adopt the voltage raising for protecting capacitance SC1, voltage-current converter circuit
The output current of VIC increases, and the shutdown moment of dc-dc converter 10 is shifted to an earlier date, and turn-on time reduces, and switch periods will shorten.
In one embodiment, it if switch periods P3 too short (being less than setting time TSET), adopts guarantor switch SS1 first and closes
When conjunction, since the second capacitance voltage VC2 is still less than the second reference voltage VREF2, trsanscondutance amplifier GA1 will be to adopting guarantor's capacitance
SC1 discharges, and adopts the voltage reduction for protecting capacitance SC1, and the output current of voltage-current converter circuit VIC lowers, dc-dc converter 10
The shutdown moment be delayed by, turn-on time increases, and switch periods will become larger.
By the above process, the switch periods of dc-dc converter 10 are arranged to setting time TSET and (ignore the second reset
The sharp pulse time of signal RS2 and third reset signal RS3).
Fig. 5 shows a 500 circuit diagram of current control circuit according to an embodiment of the invention.First electric current control
Circuit 500 processed is a specific embodiment of the first current control circuit ICTL.The first current control circuit as shown in figure 3
300 compare, and the first current control circuit 500, instead of the first trsanscondutance amplifier GA1, is used using the first trsanscondutance amplifier 501
Voltage-current converter circuit 502 further comprises that second adopts guarantor's switch SS2 instead of voltage-current converter circuit VIC.First
Trsanscondutance amplifier 502 has first input end, the second input terminal, the first output end GO1 and second output terminal GO2.Second adopts guarantor
There is switch SS2 control terminal, first end and second end, control terminal to be coupled to the second reset circuit RC2 output ends, and first
End is coupled to 501 second output terminal GO2 of trsanscondutance amplifier, and second end is coupled to first and adopts guarantor's capacitance SC1 first ends.
First trsanscondutance amplifier 501 includes bias current sources IB, the first transistor Q1, second transistor Q2, third crystal
Pipe Q3, the 4th transistor Q4, the 5th transistor Q5, the 6th transistor Q6, the 7th transistor Q7 and the 8th transistor Q8.
Bias current sources IB, has a first end and a second end, and first end is coupled to second source end PT2.First crystal
There is pipe Q1 first end, second end and control terminal, second end to be coupled to the second end of bias current sources IB, control terminal coupling
It is connected to the first input end of the first trsanscondutance amplifier 501.Second transistor Q2 has first end, second end and control terminal, the
Two ends are coupled to the second end of bias current sources IB, and control terminal is coupled to the second input terminal of the first trsanscondutance amplifier 501.The
There is three transistor Q3 first end, second end and control terminal, first end to be coupled to the first end of the first transistor Q1, the
Two ends are coupled to the first power end PT1, and control terminal is coupled to its first end.4th transistor Q4 has first end, second end
And control terminal, first end are coupled to the first end of second transistor Q2, second end is coupled to the first power end PT1, control
End processed is coupled to its first end.There is 5th transistor Q5 first end, second end and control terminal, second end to be coupled to first
Power end PT1, control terminal are coupled to the control terminal of third transistor Q3, and first end is coupled to the first trsanscondutance amplifier 501
First output end GO1.There is 6th transistor Q6 first end, second end and control terminal, second end to be coupled to the first power end
PT1, control terminal are coupled to the control terminal of the 4th transistor Q4.7th transistor Q7 has first end, second end and control
End, first end are coupled to the first end of the 6th transistor Q6, and second end is coupled to second source end PT2, control terminal coupling
It is connected to its first end.There is 8th transistor Q8 first end, second end and control terminal, second end to be coupled to second source end
PT2, control terminal are coupled to the control terminal of the 7th transistor Q7, and it is defeated that first end is coupled to the first trsanscondutance amplifier 501 second
Outlet GO2.
Voltage-current converter circuit 502 includes the 9th transistor Q9, the tenth transistor Q10 and the 11st transistor Q11.The
There is nine transistor Q9 first end, second end and control terminal, second end to be coupled to the first power end PT1, control terminal coupling
To the input terminal of voltage-current converter circuit 502；Tenth transistor Q10, have first end, second end and control terminal, first
End is coupled to the first end of the 9th transistor Q9, and second end is coupled to second source end PT2, control terminal be coupled to its first
End.There is 11st transistor Q11 first end, second end and control terminal, control terminal to be coupled to the control of the tenth transistor Q10
End processed, second end are coupled to second source end PT2, first end be coupled to the output end of voltage-current converter circuit 502 with
First electric current I1 is provided.
500 course of work of current control circuit is similar with the course of work of current control circuit 300, with reference to figure 4, at one
In embodiment, if switch periods P3 long (being more than setting time TSET), since the second current source IS2 persistently charges, first
It adopts and protects when switch SS1 is closed (T3 moment), the second capacitance voltage VC2 will be more than the second reference voltage VREF2, trsanscondutance amplifier
501 will adopt guarantor's SS1 pairs of switch first by first adopts the SC1 chargings of guarantor's capacitance, adopts the voltage raising for protecting capacitance SC1, voltage and current
The output current I1 of conversion circuit 502 is increased, and the shutdown moment of dc-dc converter 10 is shifted to an earlier date, and turn-on time reduces, switch week
Phase will shorten.
In one embodiment, it if switch periods P3 too short (being less than setting time TSET), adopts guarantor switch SS1 first and closes
When conjunction, since the second capacitance voltage VC2 is still less than the second reference voltage VREF2, trsanscondutance amplifier 501 will adopt guarantor by second
SS2 pairs of switch first, which is adopted, protects capacitance SC1 electric discharges, adopts the voltage reduction for protecting capacitance SC1, the output of voltage-current converter circuit 502
Electric current I1 lowers, and the shutdown moment of dc-dc converter 10 is delayed by, and turn-on time increases, and switch periods will become larger.
By the above process, the switch periods of dc-dc converter 10 are arranged to setting time TSET and (ignore the second reset
The sharp pulse time of signal RS2 and third reset signal RS3).
Although the present invention has been combined its specific illustrative embodiment and is described, it is therefore apparent that, it is a variety of it is alternative,
Modification and variation are apparent to those skilled in the art.The exemplary embodiment party of the present invention illustrated herein as a result,
Formula is schematical and and non-limiting.It can modify without departing from the spirit and scope of the present invention.At this
Quantifier used in disclosure "one", "an" etc. be not excluded for plural number." first ", " second " in text etc. are merely represented in
The sequencing occurred in the description of embodiment, in order to distinguish like." first ", " second " are in detail in the claims
Occur only for the purposes of the fast understanding to claim rather than in order to be limited.It is any attached in claims
Icon note should be construed as the limitation to range.
Claims (9)
1. a kind of control circuit for switching mode DC-DC converter, the converter has at least one switching tube, the control
Circuit processed includes：
Continuity signal generation circuit has first input end, the second input terminal and output end, is based on reference signal and feedback signal
Comparison result its output end provide Continuity signal, wherein the feedback signal reflects the load current of the dc-dc converter
Or output voltage；
There is cut-off signals generation circuit input terminal and output end, output end to provide cut-off signals to turn off the switching tube；
And
Logic circuit has first input end, the second input terminal and output end, is based on the Continuity signal and the cut-off signals
Switching signal is provided to control the turn-on and turn-off of the switching tube in output end；Wherein, the cut-off signals generation circuit packet
It includes：
There is first reset circuit input terminal and output end, input terminal to be coupled to the output end of the logic circuit, export
End provides the first reset signal；
There is first switch control terminal, first end and second end, control terminal to be coupled to the first reset circuit output end,
Second termination is coupled to the first power end；
First capacitance, has a first end and a second end, and first end is coupled to the first switch first end, second end coupling
To first power end；
There is first current control circuit first input end, the second input terminal and output end, first input end to be coupled to described
The output end of logic circuit is to receive the switching signal, and the second input terminal is receiving reference clock signal, output end
The first end of first capacitance is coupled to provide the first electric current, first current control circuit includes a phase discriminator, tool
There are first input end, the second input terminal and output end, first input end to be coupled to the first of first current control circuit
Input terminal, the second input terminal are coupled to the second input terminal of first current control circuit, and output end is coupled to described
The output end of first current control circuit, difference on the frequency of the phase discriminator based on the switching signal Yu the reference clock signal
Different adjustment first electric current so that the frequency of the switching signal is substantially equal to setpoint frequency；And
There is first comparator first input end, the second input terminal and output end, first input end to receive first with reference to electricity
Pressure, the second input terminal are coupled to the first end of first capacitance, and output end is configured to the cut-off signals generation circuit
Output end.
2. control circuit according to claim 1, first current control circuit also has the second input terminal to connect
The second reference voltage is received, first current control circuit includes：
There is second reset circuit input terminal and output end, input terminal to be coupled to the output end of the logic circuit, export
End provides the second reset signal；
There is third reset circuit input terminal and output end, input terminal to be coupled to the output end of second reset circuit,
Output end provides third reset signal；
Second current source, has a first end and a second end, and first end is coupled to second source end；
There is second switch control terminal, first end and second end, control terminal to be coupled to the third reset circuit output end,
Its first end is coupled to the second end of the second current source, and second end is coupled to first power end；
Second capacitance, has a first end and a second end, and first end is coupled to the second current source second end, second end coupling
It is connected to first power end；
There is first trsanscondutance amplifier first input end, the second input terminal and the first output end, first input end to be coupled to institute
The second capacitance first end is stated, the second input terminal receives second reference voltage；
First adopts guarantor's switch, and there is control terminal, first end and second end, control terminal to be coupled to the second reset circuit output
End, first end are coupled to first the first output end of trsanscondutance amplifier；
First adopts guarantor's capacitance, has a first end and a second end, and first end is coupled to described first and adopts guarantor's switch second end, the
Two ends are coupled to first power end；And
Voltage-current converter circuit, have input terminal and output end, input terminal be coupled to described first adopt protect capacitance first
End, output end are coupled to the first current control circuit output end.
3. control circuit according to claim 2, first trsanscondutance amplifier has second output terminal, first electricity
Flow control circuit further includes：
Second adopts guarantor's switch, and there is control terminal, first end and second end, control terminal to be coupled to the second reset circuit output
End, first end are coupled to the first trsanscondutance amplifier second output terminal, and second end is coupled to described first and adopts guarantor's capacitance
First end.
4. control circuit according to claim 3, first trsanscondutance amplifier include：
Bias current sources have a first end and a second end, and first end is coupled to the second source end；
There is the first transistor first end, second end and control terminal, second end to be coupled to the second of the bias current sources
End, control terminal are coupled to the first input end of first trsanscondutance amplifier；
There is second transistor first end, second end and control terminal, second end to be coupled to the second of the bias current sources
End, control terminal are coupled to the second input terminal of first trsanscondutance amplifier；
There is third transistor first end, second end and control terminal, first end to be coupled to the first of the first transistor
End, second end are coupled to first power end, and control terminal is coupled to its first end；
There is 4th transistor first end, second end and control terminal, first end to be coupled to the first of the second transistor
End, second end are coupled to first power end, and control terminal is coupled to its first end；
There is 5th transistor first end, second end and control terminal, second end to be coupled to first power end, control
End is coupled to the control terminal of the third transistor, and first end is coupled to the first trsanscondutance amplifier second output terminal；
There is 6th transistor first end, second end and control terminal, second end to be coupled to first power end, control
End is coupled to the control terminal of the 4th transistor；
There is 7th transistor first end, second end and control terminal, first end to be coupled to the first of the 6th transistor
End, second end are coupled to the second source end, and control terminal is coupled to its first end；And
There is 8th transistor first end, second end and control terminal, first end to be coupled to first trsanscondutance amplifier first
Output end, second end are coupled to the second source end, and control terminal is coupled to the control terminal of the 7th transistor.
5. control circuit according to claim 2, the voltage-current converter circuit：
There is 9th transistor first end, second end and control terminal, second end to be coupled to first power end, control
End is coupled to the input terminal of the voltage-current converter circuit；
There is tenth transistor first end, second end and control terminal, first end to be coupled to the first of the 9th transistor
End, second end are coupled to second source end, and control terminal is coupled to its first end；And
There is 11st transistor first end, second end and control terminal, control terminal to be coupled to the control of the tenth transistor
End, second end are coupled to the second source end, and first end is coupled to the output end of the voltage-current converter circuit.
6. control circuit according to claim 2, first reset circuit, the second reset circuit or third reset electricity
Road is sharp pulse generation circuit.
7. control circuit according to claim 6, first reset signal, the second reset signal or the third are multiple
The pulse width of position signal is 5 nanoseconds to 20 nanoseconds.
8. control circuit according to claim 1, wherein the switching tube is the main switch of decompression converting circuit, institute
Stating switching tube, there is first end, second end and control terminal, wherein first end to receive input voltage, and control terminal receives the switch letter
Number, the converter further includes：
There is secondary switching tube first end, second end and control terminal, wherein first end to be coupled to the second end of the main switch,
Second end is grounded, and control terminal is coupled to the logic circuit；And
Inductor has a first end and a second end, and wherein first end is electrically coupled to the second end and time switch of the main switch
The first end of pipe, second end provide the output voltage.
9. control circuit according to claim 1, wherein the Continuity signal generation circuit includes the second comparator, institute
It includes first input end, the second input terminal and output end to state the second comparator, is respectively configured as the Continuity signal generation circuit
First input end, the second input terminal and output end.
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| CN201511028529.5A CN105553265B (en) | 2015-12-31 | 2015-12-31 | Control circuit for switching type DCDC converter |
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| CN201511028529.5A CN105553265B (en) | 2015-12-31 | 2015-12-31 | Control circuit for switching type DCDC converter |
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| JP2011010512A (en) * | 2009-06-29 | 2011-01-13 | Denso Corp | Step up/down converter |
| CN102255504A (en) * | 2011-07-04 | 2011-11-23 | 成都芯源***有限公司 | Switch control circuit and method thereof |
| CN102364848A (en) * | 2011-02-01 | 2012-02-29 | 杭州士兰微电子股份有限公司 | Primary side-controlled constant current switch power supply controller and primary side-controlled constant current switch power supply control method |
| CN104201883A (en) * | 2014-07-02 | 2014-12-10 | 成都芯源***有限公司 | Control circuit for switching converter |
| CN204652216U (en) * | 2015-02-02 | 2015-09-16 | 成都芯源***有限公司 | Control circuit for switching converter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102801305B (en) * | 2012-08-14 | 2015-07-08 | 成都芯源***有限公司 | Peak current signal generation circuit, switching power supply circuit and method thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011010512A (en) * | 2009-06-29 | 2011-01-13 | Denso Corp | Step up/down converter |
| CN102364848A (en) * | 2011-02-01 | 2012-02-29 | 杭州士兰微电子股份有限公司 | Primary side-controlled constant current switch power supply controller and primary side-controlled constant current switch power supply control method |
| CN102255504A (en) * | 2011-07-04 | 2011-11-23 | 成都芯源***有限公司 | Switch control circuit and method thereof |
| CN104201883A (en) * | 2014-07-02 | 2014-12-10 | 成都芯源***有限公司 | Control circuit for switching converter |
| CN204652216U (en) * | 2015-02-02 | 2015-09-16 | 成都芯源***有限公司 | Control circuit for switching converter |
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