CN103973113B - Control circuit and method for buck-boost power converter - Google Patents
Control circuit and method for buck-boost power converter Download PDFInfo
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- CN103973113B CN103973113B CN201410147913.6A CN201410147913A CN103973113B CN 103973113 B CN103973113 B CN 103973113B CN 201410147913 A CN201410147913 A CN 201410147913A CN 103973113 B CN103973113 B CN 103973113B
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Abstract
Disclosed is a control circuit for a buck-boost power converter. The control circuit is used for providing a control signal to drive a buck-boost power level so as to convert an input voltage into an output voltage. The buck-boost power level comprises an inductor and at least two switches connected with the inductor. The control circuit is characterized by comprising a feedback circuit, an error amplifier, a dynamic working period generator and a driving circuit, wherein the feedback circuit detects the output voltage to generate a feedback signal, the error amplifier is connected with the feedback circuit and amplifies a difference value between the feedback signal and a reference voltage to generate an error signal, the dynamic working period generator generates a first signal according to a detection signal after being started, and the driving circuit is connected with the error amplifier and the dynamic working period generator and determines the control signal according to the error signal and the first signal. The control circuit and method for the buck-boost power converter have the advantages that the on-off switching sequence is optimized, switching losses are reduced, efficiency is improved, and output ripples are reduced.
Description
Technical field
The present invention relates to a kind of buck-boost power converter, is a kind of buck-boost power converter specifically
Control circuit and method.
Background technology
Fig. 1 shows known synchronous mode buck-boost power converter 10, and it includes step-down/up type power stage 12 and control
Circuit processed 22 provides switch SWA, SWB, SWC and SWD that signal VA, VB, VC and VD switch respectively in step-down/up type power stage 12
So that input voltage vin is converted to into output voltage Vo.In control circuit 14, resistance R1 and R2 pressure-dividing output voltage Vo is produced back
Credit VFB, error amplifier 24 amplifies the difference between feedback signal VFB and reference voltage Vref and produces signal VCL to letter
Number generator 22, signal generator 22 provides signal VU, VX and VY, and wherein signal VU is related to signal VCL, and signal VX and VY are
Sawtooth signal, comparator 18 comparison signal VU and VX produce signal VZ1, and comparator 20 comparison signal VU and VY produce signal
VZ2, logic circuit 16 produces signal VA, VB, VC and VD according to signal VZ1 and VZ2.
Fig. 2 shows the oscillogram of signal in Fig. 1, and wherein waveform 26 is signal VY, and waveform 28 is signal VU, and waveform 30 is letter
Number VX, waveform 32 is signal VZ1, and waveform 34 is signal VZ2, and waveform 36 is signal VA, and waveform 38 is signal VB, and waveform 40 is letter
Number VC, waveform 42 is signal VD.With reference to Fig. 1 and Fig. 2, when signal VX is more than signal VU, such as time t1 to t2, signal VZ1 are
Low level, as shown in waveform 28,30 and 32, when signal VX is less than signal VU, such as time t2 to t5, signal VZ1 are high levle.
When signal VY is more than signal VU, to t3, signal VZ2 is low level to such as time t0, as shown in waveform 26,28 and 34, works as signal
When VY is less than signal VU, such as time t3 to t4, signal VZ2 are high levle.Hypothesis represents output voltage Vo's with time t1 to t5
A cycle, during time t1 to t2, step-down/up type power stage 12 is in first state, now switchs SWA and SWC and closes
(turn off) and switch SWB and SWD and open (turn on), as shown in waveform 36 to 42.During time t2 to t3, lifting
Pressure type power stage 12 is in the second state, now switchs SWA and SWD and opens and switch SWB and SWC and close.In time t3 to t4
Period, step-down/up type power stage 12 is in the third state, now switchs SWA and SWC and opens and switch SWB and SWD and close.When
Between during t4 to t5, step-down/up type power stage 12 returns to the second state.Wherein the second state occur in one cycle it is secondary, such as
Fruit can change transfer sequence and come the second state twice together, can reduce switch cost and improve efficiency.Additionally, when letter
Number VU rises or falls and during the valley of the peak value of approach signal VX or signal VY, the work period (duty) of signal VB or VC will
It is very short, therefore switch SWB or SWC and may not also fully open (turn on) and just and shut, this except increase switch cost it
Outward without in all senses.
U.S. Patent number 7,176,667 is it is also proposed that a kind of control circuit of buck-boost power converter, it is in buck
Switch with the pulse-width modulation signal of output voltage Vo adjusting pulsewidths and the signal deciding of a fixed pulse width using one during pattern
The switching of SWA, SWB, SWC and SWD, however, the mode of this insertion fixed pulse width signal is likely to result in not in patten transformation
The continuous work period, and then cause big output ripple.
Therefore the control circuit of known buck-boost power converter there are problems that above-mentioned a variety of inconvenience and.
The content of the invention
The purpose of the present invention, is the control circuit and method for proposing a kind of buck-boost power converter.
It is another object of the present invention to propose it is a kind of optimization the sequence of switches with improve efficiency control circuit and
Method.
A further object of the present invention, is to propose a kind of control circuit and method for reducing output ripple.
Another object of the present invention, is to propose a kind of control of the transient response for accelerating and normal operating being returned to by battery saving mode
Circuit processed and method.
For achieving the above object, technical solution of the invention is：
A kind of control circuit of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control circuit includes：
Feedback circuit, detects that the output voltage produces feedback signal；
Error amplifier connects the feedback circuit, and the difference amplified between the feedback signal and a reference voltage is produced
Error signal；
Dynamic duty period generator, the first signal is produced after being activated according to detection signal；And
Drive circuit connects the error amplifier and dynamic duty period generator, according to the error signal and first
Control signal described in signal deciding.
The control circuit of the buck-boost power converter of the present invention can also be using following technical measures come further
Realize.
Aforesaid control circuit, wherein detection signal and the input voltage, output voltage, by the inductance of the inductance
The variable quantity wherein at least one of electric current and the output voltage is related.
Aforesaid control circuit, wherein the dynamic duty period generator provides compensation letter according to the detection signal
Number.
Aforesaid control circuit, wherein the dynamic duty period generator includes：
Analog-digital converter, by the detection signal thermal compensation signal is converted to；And
Digital analog converter connects the analog-digital converter, and the thermal compensation signal is converted to into first letter
Number.
Aforesaid control circuit, wherein further including work period compensator connects the error amplifier and dynamic duty week
Phase generator, according to the thermal compensation signal error signal is compensated.
Aforesaid control circuit, wherein the work period compensator includes：
Bleeder circuit, error signal produces first voltage according to the thermal compensation signal partial pressure；
Voltage current adapter connects the bleeder circuit, and the first voltage is converted to into electric current；
Resistance is connected between the error amplifier and voltage current adapter, produces one second in response to the electric current electric
Pressure is for the adjustment error signal.
Aforesaid control circuit, wherein the drive circuit includes：
First comparator connects the error amplifier, and the comparison error signal and a sawtooth signal produce first and compare
Compared with signal；
Second comparator connects the dynamic duty period generator, and comparison first signal and sawtooth signal are produced
Second comparison signal；And
Logic circuit connects the first comparator and the second comparator, is produced according to described first and second comparison signal
The control signal.
Aforesaid control circuit, wherein further including mode selector connects the dynamic duty period generator according to described
Detection signal produces enable signal to start the dynamic duty period generator.
Aforesaid control circuit, wherein further including mode selector connects the dynamic duty period generator according to described
Error signal produces enable signal to start the dynamic duty period generator.
Aforesaid control circuit, wherein further including strangulation detector connects the error amplifier, according to the second detection letter
The level of number error signal described in strangulation, second detection signal and the input voltage, output voltage and inductive current its
In it is at least one related.
A kind of control method of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control method comprises the following steps：
(A) detect that the output voltage produces feedback signal；
(B) difference amplified between the feedback signal and a reference voltage produces error signal；
(C) the first signal is determined according to detection signal；
(D) first signal is triggered according to enable signal；And
(E) control signal according to the error signal and the first signal deciding.
Aforesaid control method, wherein the detection signal and the input voltage, output voltage, by the inductance
The variable quantity wherein at least one of inductive current and the output voltage is related.
Aforesaid control method, wherein further including
Thermal compensation signal is provided according to detection signal；And
The error signal is compensated according to the thermal compensation signal.
Aforesaid control method, wherein step C includes：
The detection signal is converted to into the thermal compensation signal；And
The thermal compensation signal is converted to into first signal.
Aforesaid control method, wherein the step of compensation error signal according to the thermal compensation signal includes：
Error signal produces first voltage according to the thermal compensation signal partial pressure；
The first voltage is converted to into electric current to a resistance to produce a second voltage；And
The error signal is adjusted by the second voltage.
Aforesaid control method, wherein step E includes：
The comparison error signal and a sawtooth signal produce the first comparison signal；
Comparison first signal and sawtooth signal produce the second comparison signal；And
The control signal is produced according to described first and second comparison signal.
Aforesaid control method, wherein further include producing the enable signal according to the detection signal.
Aforesaid control method, wherein further include producing the enable signal according to the error signal.
Aforesaid control method, wherein the level of the error signal according to the second detection signal strangulation is further included, it is described
Second detection signal is related to the input voltage, output voltage and inductive current wherein at least one.
A kind of control circuit of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control circuit includes：
Feedback circuit, detects that the output voltage produces feedback signal；
Error amplifier connects the feedback circuit, and the difference amplified between the feedback signal and a reference voltage is produced
First error signal；
Work period compensator connects the error amplifier, compensates first error signal according to thermal compensation signal and produces
Second error signal；
Work period generator connects the work period compensator, and one first signal is produced after being activated；And
Drive circuit connects the work period compensator and work period generator, according to second error signal and
Control signal described in first signal deciding.
Aforesaid control circuit, wherein the work period compensator includes：
Bleeder circuit, the first error signal produces first voltage according to the thermal compensation signal partial pressure；
Voltage current adapter connects the bleeder circuit, and the first voltage is converted to into electric current；And
Resistance is connected between the error amplifier and voltage current adapter, produces one second in response to the electric current electric
Pressure subtracts each other generation second error signal with first error signal.
Aforesaid control circuit, wherein the work period generator provides dynamic first letter according to detection signal
Number, the detection signal and the input voltage, output voltage, the inductive current by the inductance and the output voltage
Variable quantity wherein at least one is related.
Aforesaid control circuit, wherein the work period generator produces the compensation letter according to the detection signal
Number.
Aforesaid control circuit, wherein the work period generator includes：
Analog-digital converter, by the detection signal thermal compensation signal is converted to；And
Digital analog converter connects the analog-digital converter, and the thermal compensation signal is converted to into first letter
Number.
Aforesaid control circuit, wherein the work period generator provides fixed first signal.
Aforesaid control circuit, wherein the drive circuit includes：
First comparator connects the work period compensator, and comparison second error signal and a sawtooth signal are produced
Raw first comparison signal；
Second comparator connects the work period generator, and comparison first signal and sawtooth signal produce second
Comparison signal；And
Logic circuit connects the first comparator and the second comparator, is produced according to described first and second comparison signal
The control signal.
Aforesaid control circuit, wherein further including mode selector connects the work period generator, according to detection letter
Number produce enable signal to start the work period generator, it is the detection signal and the input voltage, output voltage, logical
Cross the inductive current of the inductance and the variable quantity wherein at least one correlation of the output voltage.
Aforesaid control circuit, wherein further including mode selector connects the work period generator, according to the mistake
Difference signal produces enable signal to start the work period generator.
Aforesaid control circuit, wherein further including strangulation detector connects the error amplifier, according to detection signal pincers
The level of first error signal is made, the detection signal is with the input voltage, output voltage and by the inductance
Inductive current wherein at least one is related.
A kind of control method of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control method comprises the following steps：
(A) detect that the output voltage produces feedback signal；
(B) difference amplified between the feedback signal and a reference voltage produces the first error signal；
(C) compensate first error signal and produce the second error signal；
(D) the first signal is triggered according to enable signal；And
(E) control signal according to second error signal and the first signal deciding.
Aforesaid control method, wherein step C includes determining thermal compensation signal for compensation described the according to detection signal
One error signal, the detection signal and the input voltage, output voltage, the inductive current by the inductance and described defeated
The variable quantity wherein at least one for going out voltage is related.
Aforesaid control method, wherein step C includes：
The first error signal produces first voltage according to the thermal compensation signal partial pressure；
The first voltage is converted to into electric current to a resistance to produce a second voltage；And
First error signal is deducted into second voltage and produces second error signal.
Aforesaid control method, wherein further include providing dynamic first signal according to the detection signal.
Aforesaid control method, wherein the step of first signal dynamic according to detection signal offer includes：
Detection signal is converted to into the thermal compensation signal；And
The thermal compensation signal is converted to into first signal.
Aforesaid control method, wherein further include providing fixed first signal.
Aforesaid control method, wherein step E includes：
Comparison second error signal and a sawtooth signal produce the first comparison signal；
Comparison first signal and sawtooth signal produce the second comparison signal；And
The control signal is produced according to described first and second comparison signal.
Aforesaid control method, wherein further include produce the enable signal according to detection signal, the detection signal with
The variable quantity wherein at least one of the input voltage, output voltage, the inductive current by the inductance and the output voltage
Individual correlation.
Aforesaid control method, wherein further include producing the enable signal according to the error signal.
Aforesaid control method, wherein the level of the first error signal according to detection signal strangulation is further included, it is described
Detection signal and the input voltage, output voltage and related by the inductive current wherein at least one of the inductance.
A kind of control circuit of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control circuit includes：
Feedback circuit, detects that the output voltage produces feedback signal；
Error amplifier connects the feedback circuit, and the difference amplified between the feedback signal and a reference voltage is produced
Error signal；
Strangulation detector connects the error amplifier, the level of error signal according to detection signal strangulation；And
Drive circuit connects the error amplifier, the control letter according to the error signal and one first signal deciding
Number.
Aforesaid control circuit, wherein the detection signal is with the input voltage, output voltage and by the inductance
Inductive current wherein at least one it is related.
Aforesaid control circuit, wherein further include dynamic duty period generator produces described the according to the second detection signal
One signal, the variable quantity of second detection signal and the input voltage, output voltage, inductive current and the output voltage
Wherein at least one is related.
Aforesaid control circuit, wherein the dynamic duty period generator is further included being carried according to second detection signal
For thermal compensation signal.
Aforesaid control circuit, wherein the dynamic duty period generator includes：
Analog-digital converter, by second detection signal thermal compensation signal is converted to；And
Digital analog converter connects the analog-digital converter, and the thermal compensation signal is converted to into first letter
Number.
Aforesaid control circuit, wherein further including work period compensator connects the error amplifier and dynamic duty week
Phase generator, according to the thermal compensation signal error signal is compensated.
Aforesaid control circuit, wherein the work period compensator includes：
Bleeder circuit, error signal produces first voltage according to the thermal compensation signal partial pressure；
Voltage current adapter connects the bleeder circuit, and the first voltage is converted to into electric current；And
Resistance is connected between the error amplifier and voltage current adapter, produces one second in response to the electric current electric
The pressure adjustment error signal.
Aforesaid control circuit, wherein further including mode selector connects the dynamic duty period generator according to described
Second detection signal produces enable signal to start the dynamic duty period generator.
Aforesaid control circuit, wherein further including mode selector connects the dynamic duty period generator according to described
Error signal produces enable signal to start the dynamic duty period generator.
Aforesaid control circuit, wherein the drive circuit includes：
First comparator connects the error amplifier, and the comparison error signal and a sawtooth signal produce first and compare
Compared with signal；
Second comparator, comparison first signal and sawtooth signal produce the second comparison signal；And
Logic circuit connects the first comparator and the second comparator, is produced according to described first and second comparison signal
The control signal.
A kind of control method of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control method comprises the following steps：
(A) detect that the output voltage produces feedback signal；
(B) difference amplified between the feedback signal and a reference voltage produces error signal；
(C) according to detection signal strangulation error signal level；And
(D) control signal according to the error signal and one first signal deciding.
Aforesaid control method, wherein the detection signal is with the input voltage, output voltage and by the inductance
Inductive current wherein at least one it is related.
Aforesaid control method, wherein further include determining first signal, second inspection according to the second detection signal
Survey signal related to the variable quantity wherein at least one of the input voltage, output voltage, inductive current and the output voltage.
Aforesaid control method, wherein further include providing thermal compensation signal to compensate the mistake according to second detection signal
Difference signal.
Aforesaid control method, wherein the step of decision first signal includes：
Second detection signal is converted to into thermal compensation signal；And
The thermal compensation signal is converted to into first signal.
Aforesaid control method, wherein the step of compensation error signal includes：
Error signal produces first voltage according to the thermal compensation signal partial pressure；
The first voltage is converted to into electric current and produces a second voltage to a resistance；And
The error signal is adjusted according to the second voltage.
Aforesaid control method, wherein further include to produce enable signal to trigger described the according to second detection signal
One signal.
Aforesaid control method, wherein to further include produce enable signal according to the error signal to trigger first letter
Number.
Aforesaid control method, wherein step D includes：
The comparison error signal and a sawtooth signal produce the first comparison signal；
Comparison first signal and sawtooth signal produce the second comparison signal；And
The control signal is produced according to described first and second comparison signal.
A kind of control circuit of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control circuit includes：
Feedback circuit, detects that the output voltage produces feedback signal；
Error amplifier connects the feedback circuit, and the difference amplified between the feedback signal and a reference voltage is produced
First error signal；
Strangulation detector connects the error amplifier, the standard of the first error signal according to first detection signal strangulation
Position；
Work period compensator connects the error amplifier, compensates first error signal according to thermal compensation signal and produces
Second error signal；
Dynamic duty period generator connects the work period compensator, is produced according to the second detection signal after being activated
Raw one first signal；
Mode selector connects the dynamic duty period generator, there is provided enable signal is all to start the dynamic duty
Phase generator；And
Drive circuit connects the work period compensator and dynamic duty period generator, is believed according to second error
Number and control signal described in the first signal deciding.
Aforesaid control circuit, wherein the first detection signal is with the input voltage, output voltage and by described
The inductive current wherein at least one of inductance is related.
Aforesaid control circuit, wherein second detection signal and the input voltage, output voltage, inductive current and
The variable quantity wherein at least one of the output voltage is related.
Aforesaid control circuit, wherein the work period compensator includes：
Bleeder circuit, the first error signal produces first voltage according to the thermal compensation signal partial pressure；
Voltage current adapter, connects the bleeder circuit, and the first voltage is converted to into electric current；
Resistance, is connected between the error amplifier and voltage current adapter, and in response to the electric current one second is produced
Voltage subtracts each other generation second error signal with first error signal.
Aforesaid control circuit, wherein the dynamic duty period generator is according to second detection signal is provided
Thermal compensation signal gives the work period compensator.
Aforesaid control circuit, wherein the dynamic duty period generator includes：
Analog-digital converter, by second detection signal thermal compensation signal is converted to；And
Digital analog converter connects the analog-digital converter, and the thermal compensation signal is converted to into first letter
Number.
Aforesaid control circuit, wherein the mode selector produces the enable letter according to second detection signal
Number.
Aforesaid control circuit, wherein the mode selector produces the enable signal according to first error signal
Device.
Aforesaid control circuit, wherein the drive circuit includes：
First comparator connects the work period compensator, and comparison second error signal and a sawtooth signal are produced
Raw first comparison signal；
Second comparator connects the dynamic duty period generator, and comparison first signal and sawtooth signal are produced
Second comparison signal；And
Logic circuit connects the first comparator and the second comparator, is produced according to described first and second comparison signal
The control signal.
A kind of control method of buck-boost power converter, to provide control signal drive step-down/up type power stage with
Output voltage is converted input voltage into, the step-down/up type power stage includes inductance and at least two switch connections inductance,
It is characterized in that the control method comprises the following steps：
(A) detect that the output voltage produces feedback signal；
(B) difference amplified between the feedback signal and a reference voltage produces the first error signal；
(C) according to first detection signal strangulation the first error signal level；
(D) one first signal is triggered according to enable signal；
(E) first signal is determined according to the second detection signal；
(F) compensate first error signal and produce the second error signal；And
(G) control signal according to second error signal and the first signal deciding.
Aforesaid control method, wherein the first detection signal is with the input voltage, output voltage and by described
The inductive current wherein at least one of inductance is related.
Aforesaid control method, wherein second detection signal and the input voltage, output voltage, inductive current and
The variable quantity wherein at least one of the output voltage is related.
Aforesaid control method, wherein step D includes producing the enable signal according to second detection signal.
Aforesaid control method, wherein step D includes producing the enable signal according to first error signal.
Aforesaid control method, wherein step F includes determining thermal compensation signal to mend according to second detection signal
Repay first error signal.
Aforesaid control method, wherein step E includes：
Second detection signal is converted to into the thermal compensation signal；And
The thermal compensation signal is converted to into the first signal of simulation.
Aforesaid control method, wherein step F is further included：
The first error signal produces first voltage according to the thermal compensation signal partial pressure；
The first voltage is converted to into electric current to a resistance to produce a second voltage；And
First error signal is deducted into second voltage and produces second error signal.
Aforesaid control method, wherein step G includes：
Comparison second error signal and a sawtooth signal produce the first comparison signal；
Comparison first signal and sawtooth signal produce the second comparison signal；And
The control signal is produced according to described first and second comparison signal.
After above-mentioned technical proposal, the present invention buck-boost power converter control circuit and method have it is following
Advantage：
1. the sequence of switches is optimized, switch cost is reduced, is improved efficiency.
2. output ripple is reduced.
Description of the drawings
Fig. 1 is known synchronous mode buck-boost power converter schematic diagram；
Fig. 2 is the oscillogram of signal in Fig. 1；
Fig. 3 is embodiments of the invention schematic diagram；
Fig. 4 is step-down/up type power stage current path schematic diagram in buck mode in Fig. 3；
Fig. 5 is current path schematic diagram of the step-down/up type power stage under buck-boost mode in Fig. 3；
Fig. 6 is current path schematic diagram of the step-down/up type power stage under boost mode in Fig. 3；
Fig. 7 is the oscillogram of signal in Fig. 3；
Fig. 8 is the oscillogram of signal in Fig. 3；
Fig. 9 is the oscillogram of signal in Fig. 3；
Figure 10 is the embodiment schematic diagram of work period compensator in Fig. 3；And
Figure 11 is the embodiment schematic diagram of logic circuit, dynamic duty period generator and mode selector in Fig. 3.
In figure, 10, buck-boost power converter 12, step-down/up type power stage 14, control circuit 16, logic circuit 18,
Comparator 20, comparator 22, signal generator 24, error amplifier 26, the waveform 28 of signal VY, the waveform 30 of signal VU, letter
The waveform 32 of number VX, the waveform 34 of signal VZ1, the waveform 36 of signal VZ2, the waveform 38 of signal VA, the waveform 40 of signal VB, letter
The waveform 42 of number VC, the waveform 50 of signal VD, buck-boost power converter 52, step-down/up type power stage 54, control circuit 55,
Drive circuit 56, logic circuit 58, comparator 60, comparator 62, work period compensator 64, dynamic duty period generator
66th, pattern strangulation detector 68, mode selector 70, error amplifier 72, feedback circuit 74, step-down charge path are omitted in pulse
76th, step-down discharge path 78, boost charge path 80, step-down charging or step-up discharge path 82, step-down discharge path 84, boosting
Discharge path 86, boost charge path 90, the waveform 94 of the waveform 92, sawtooth signal Vramp of signal Vcomp ', the first signal
The waveform 96 of Di, the waveform 100 of inductive current IL, the waveform 104 of the waveform 102, sawtooth signal Vramp of signal Vcomp ',
The waveform 106 of the first signal Di, the waveform 110 of inductive current IL, the waveform 112, sawtooth signal Vramp of signal Vcomp '
Waveform 114, the waveform 116 of the first signal Di, the waveform 118 of inductive current IL, the average current 120 of inductive current IL, buffering
Device 122, bleeder circuit 124, buffer 126, voltage current adapter 130, sawtooth generator 132, analog-digital converter
134th, digital analog converter 138, comparator 140, phase inverter 142, NAND gate 144, phase inverter.
Specific embodiment
With reference to embodiments and its accompanying drawing to the present invention illustrate further.
Referring now to Fig. 3, Fig. 3 shows the schematic diagram of the embodiment of the present invention.As illustrated, the step-down/up type Power convert
In device 50, control circuit 54 provides control signal VA, VB, VC and VD and switches respectively in step-down/up type power stage 52 and connects with inductance L
Switch SWA, SWB, SWC and the SWD for connecing, by input voltage vin output voltage Vo is converted to.In control circuit 54, feedback
Circuit 72 detects that the output voltage Vo produces feedback signal VFB, and error amplifier 70 amplifies feedback signal VFB and reference voltage
Difference between VREF produces error signal Vcomp, and pulse omits pattern strangulation detector 66 according to detection signal S1 strangulations
(clamp) level of error signal Vcomp, wherein detection signal S1 and input voltage vin, output voltage Vo and inductive current IL
Wherein at least one is relevant, and mode selector 68 produces signal S3 to logic circuit 56 and produces enable according to detection signal S2
Signal EN enable dynamic duties period generator 64, wherein detection signal S2 and input voltage vin, output voltage Vo, inductance electricity
Stream IL and output voltage variable quantity wherein at least one are relevant, and in other embodiments, mode selector 68 can also be using mistake
Producing signal S3 and EN, dynamic duty period generator 64 determines dynamic first to difference signal Vcomp according to detection signal S2
Signal Di and thermal compensation signal DDC, work period compensator 62 compensates error signal Vcomp and produces error according to thermal compensation signal DDC
Signal Vcomp ', drive circuit 55 is according to sawtooth signal Vramp, error signal Vcomp ', the first signal Di and signal S3 produces
Raw control signal VA, VB, VC and VD.Drive circuit 55 includes the comparison signal Vcomp ' of comparator 58 and sawtooth signal Vramp
Comparison signal S4 is produced, comparator 60 compares sawtooth signal Vramp and the first signal Di produces comparison signal S5, and logic
Circuit 56 determines control signal VA, VB, VC and VD according to signal S3, S4 and S5.
Fig. 4 shows the current path in buck mode of step-down/up type power stage 52, in buck mode, switch SWC dimensions
Hold closing (turn off) and switch SWD and be maintained open (tunr on), when switching SWA and opening and switch SWB closings drop is formed
Pressure charge path 74, when switching SWA and closing and switch SWB openings step-down discharge path 76 is formed.Fig. 5 shows step-down/up type work(
Current path of the rate level 52 under buck-boost mode, under buck-boost mode, when switch SWA and SWC open and switch SWB and
Boost charge path 78 is formed when SWD is closed, switch SWB and SWC forms step-down and fills when closing when switch SWA and SWD openings
Electricity or step-up discharge path 80, when switching SWB and SWD and opening and switch SWA and SWC closings step-down discharge path 82 is formed.
Fig. 6 shows current path of the step-down/up type power stage 52 under boost mode, under boost mode, switch SWA be maintained open and
Switch SWB is remained off, when switching SWC and opening and switch and boost charge path 86 is formed when SWD is closed, when switch SWC is closed
And switch when SWD is opened and form step-up discharge path 84.
Fig. 7 shows the oscillogram of signal in Fig. 3, and wherein waveform 90 is error signal Vcomp ', waveform 92 is sawtooth waveforms letter
Number Vramp, waveform 94 is the first signal Di, and waveform 96 is the inductive current IL by inductance L.With reference to Fig. 3 and Fig. 7, in step-down
During pattern, dynamic duty period generator 64 is closed, therefore the first signal Di is zero, therefore switch SWC is remained off and switched SWD
Be maintained open, error signal Vcomp ' and sawtooth signal Vramp then controlling switch SWA and SWB switching with control inductance electricity
The rising and decline of stream IL, as shown in waveform 90,92 and 96, during step-down charge cycle D2 ', such as time t6 to t7, switch
SWA is opened and is switched SWB and close therefore inductive current IL risings, during step-down discharge cycle D3 ', such as time t7 to t8, and switch
SWA is closed and is switched SWB and open therefore inductive current IL declines.When buck-boost mode is entered by decompression mode, such as time t8 institutes
Show, mode selector 68 sends enable signal EN enable dynamic duties period generator 64, therefore the first signal Di is not zero, such as
Shown in waveform 94, therefore boost charge cycle D1, such as time t8 to t9 are produced, because the first signal Di changes with detection signal S2,
Therefore boost charge cycle D1 also changes with signal S2, in order to avoid causing big output ripple because inserting boost charge cycle D1,
Dynamic duty period generator 64 sends thermal compensation signal DDC to work period compensator 62 so that error signal Vcomp ' with first
The rising of signal Di and decline, as shown in waveform 90 and 94, therefore be depressured charge cycle and D2 be reduced to by D2 ' and step-down discharge is all
It is D3 that phase is increased by D3 ', and such inductive current IL is identical with level is terminated in the initial level in each cycle, such as time t8 and
Shown in t11, therefore it is avoided that big output ripple.From the waveform 96 of Fig. 7, time t8 to t11 can be considered a cycle, when wherein
Between t8 to t9 be boost charge state, time t9 to t10 for step-down charged state, time t10 to t11 be step-down discharge state,
Do not repeat identical state in each cycle, in other words, the optimal Switching SWA of control circuit 54 of the present invention,
The transfer sequence of SWB, SWC and SWD, thus reduce switch cost.Although only illustrating to be entered by decompression mode in the present embodiment
Operation during buck-boost mode, but those skilled in the art easily can push away by boost mode entrance very by the present embodiment
Operation during buck-boost mode, therefore repeat no more in this.
Fig. 8 shows the oscillogram of signal in Fig. 3, and wherein waveform 100 is error signal Vcomp ', waveform 102 is sawtooth waveforms
Signal Vramp, waveform 104 is the first signal Di, and waveform 106 is the inductive current IL by inductance L.In current Power convert
Battery saving mode is designed with device with energy saving, pattern (Pulse Skipping Mode are omitted in such as pulse;PSM), tradition is worked as
Buck-boost power converter when returning to buck-boost mode by battery saving mode, it is necessary to be introduced into decompression mode, then wait for
Error signal Vcomp could enter after a critical value buck-boost mode by above freezing rising to, and error signal Vcomp will be by liter above freezing
Several cycles may be needed to the critical value.With reference to Fig. 8, when the buck-boost power converter 50 of the application present invention will be by saving
When power mode returns to buck-boost mode, decompression mode is returned to by battery saving mode in a cycle, because pattern is omitted in pulse
Strangulation detector 66 can be according to the level of detection signal S1 dynamic strangulation error signals Vcomp, therefore error signal Vcomp is not
Slowly risen with from zero, but in decompression mode, dynamic duty period generator 64 is closed, therefore error signal Vcomp '=Vcomp,
That is error signal Vcomp ' level of the close critical value is clamped at, as shown in waveform 100, therefore at second
Buck-boost power converter 50 enters buck-boost mode by decompression mode immediately during the cycle, and instantaneous in the 3rd end cycle
Response.In other words, the pulse in control circuit 54 is omitted pattern strangulation detector 66 and can accelerate to return to lifting by battery saving mode
The transient response of die pressing type.
Fig. 9 shows the oscillogram of signal in Fig. 3, and wherein waveform 110 is error signal Vcomp ', waveform 112 is sawtooth waveforms
Signal Vramp, waveform 114 is the first signal Di, and waveform 116 is the inductive current IL by inductance L, and waveform 118 is inductance electricity
The average current of stream IL.In buck-boost mode, when the first signal Di rises, as shown in waveform 114, boost charge cycle D1
Increase, therefore the average current of inductive current IL and then rises, as shown by the waveform 118, while dynamic duty period generator 64 will
Output thermal compensation signal DDC is to work period compensator 62 so that error signal Vcomp ' decline, as shown in waveform 110.When first
When signal Di changes, the average current of inductive current IL will and then change, therefore control circuit 54 is without the need for by error signal
Vcomp is adjusting inductive current IL.
Figure 10 shows the embodiment of work period compensator 62 in Fig. 3, wherein from the error signal of error amplifier 70
Respectively buffered device 120 and 124 is sent to bleeder circuit 122 and resistance R3 to Vcomp, by multiple resistance RD1～RDN and multiple opens
Partial pressure error signal Vcomp of bleeder circuit 122 for closing SW1～SWN compositions produces voltage Vd, and the plurality of switch SW1～SWN is received
Control in thermal compensation signal DDC from dynamic duty period generator 64, voltage Vd is converted to electric current by voltage current adapter 126
Id, electric current Id produce voltage VR3 by resistance R3, and error signal Vcomp to be deducted and obtain error signal Vcomp after voltage VR3 '.
Figure 11 shows the embodiment of logic circuit 56, dynamic duty period generator 64 and mode selector 68 in Fig. 3.
The sawtooth generator 130 being made up of switch M2, current source Ich and electric capacity C in Figure 11 provides sawtooth signal Vramp.Logic
Circuit 56 includes phase inverter 140 and 144 and NAND gate 142, in logic circuit 56, to make from the signal S4 of comparator 58
For control signal VB, control signal VA is produced after the inverted control signal VB of phase inverter 140, NAND gate 142 is according to signal S3 and S5
Signal VD is produced, signal VC is produced after the inversion signal VD of phase inverter 144.Dynamic duty period generator 64 turns including simulation numeral
Parallel operation 132 and digital resolution converter 134, in dynamic duty period generator 64, signal S2 Jing analog-digital converters 132
After being converted to thermal compensation signal DDC of numeral, thermal compensation signal DDC is converted to again digital analog converter 134 first letter of simulation
Number Di.Mode selector 68 compares detection signal S2 including comparator 138 and critical value VTH produces signal S3, critical value VTH system
For judging whether for power supply changeover device 50 to switch to buck-boost mode, wherein critical value VTH can be definite value or by inductance electricity
The variable quantity of stream IL or output voltage Vo is determined.Dynamic critical value VTH can improve the efficiency of power supply changeover device 50 and defeated
Go out the ripple of voltage Vo, additionally can be with accelerating weight or power supply transient response.Change with inductive current IL in critical value VTH
In the case of, when heavier loads and larger inductive current, critical value VTH adds ambassador's buck-boost power converter 50 to be operated in liter
Decompression mode, now charging and discharging is more quick, thus is avoided that excessive ripple is produced.In critical value VTH with output electricity
Pressure Vo variable quantity change in the case of, when output voltage Vo variable quantity increase when, critical value VTH increase, therefore increase into
Enter the workspace of buck-boost mode, now inductive current IL easily fills and easily puts, therefore the ripple of output voltage Vo can be reduced.
The fixed work period generator for providing fixed signal can also be used in other embodiments to replace dynamic duty
Period generator 64.
Above example is used for illustrative purposes only, rather than limitation of the present invention, about the technology people of technical field
Member, without departing from the spirit and scope of the present invention, can also make various conversion or change.Therefore, all equivalents
Technical scheme should also belong to scope of the invention, should be limited by each claim.
Claims (16)
1. a kind of control circuit of buck-boost power converter, drives step-down/up type power stage to incite somebody to action to provide control signal
Input voltage is converted to output voltage, and the step-down/up type power stage includes inductance and at least two switch connections inductance, its
It is characterised by that the control circuit includes：
Feedback circuit, to detect that the output voltage produces feedback signal；
Error amplifier connects the feedback circuit, produces to amplify the difference between the feedback signal and a reference voltage
First error signal；
Dynamic duty period generator, believes to provide thermal compensation signal and produce first according to first detection signal after being activated
Number；
Work period compensator connects the error amplifier and dynamic duty period generator, to according to the thermal compensation signal
Compensate first error signal and produce the second error signal；And
Drive circuit connects the error amplifier and dynamic duty period generator, to according to second error signal and
Control signal described in first signal deciding.
2. control circuit as claimed in claim 1, it is characterised in that the first detection signal and the input voltage, defeated
The variable quantity wherein at least one for going out voltage, the inductive current by the inductance and the output voltage is related.
3. control circuit as claimed in claim 1, it is characterised in that the dynamic duty period generator includes：
Analog-digital converter, the first detection signal is converted to into the thermal compensation signal；And
Digital analog converter connects the analog-digital converter, the thermal compensation signal is converted to into first letter
Number.
4. control circuit as claimed in claim 1, it is characterised in that the work period compensator includes：
Bleeder circuit, to the first error signal according to the thermal compensation signal partial pressure first voltage is produced；
Voltage current adapter connects the bleeder circuit, the first voltage is converted to into electric current；
Resistance is connected between the error amplifier and voltage current adapter, and to respond the electric current one second is produced
Voltage is for adjustment first error signal.
5. control circuit as claimed in claim 1, it is characterised in that the drive circuit includes：
First comparator connects the work period compensator, produces to relatively more described second error signal and a sawtooth signal
Raw first comparison signal；
Second comparator connects the dynamic duty period generator, produces to relatively more described first signal and sawtooth signal
Second comparison signal；And
Logic circuit connects the first comparator and the second comparator, to be produced according to described first and second comparison signal
The control signal.
6. control circuit as claimed in claim 1, it is characterised in that further include mode selector and connect the dynamic duty week
Phase generator, to produce enable signal to start the dynamic duty period generator according to the first detection signal.
7. control circuit as claimed in claim 1, it is characterised in that further include mode selector and connect the dynamic duty week
Phase generator, to produce enable signal to start the dynamic duty period generator according to first error signal.
8. control circuit as claimed in claim 1, it is characterised in that further include strangulation detector and connect the error and amplify
Device, to the level of the first error signal according to the second detection signal strangulation, second detection signal and the input
Voltage, output voltage and the inductive current wherein at least one correlation for passing through the inductance.
9. a kind of control method of buck-boost power converter, drives step-down/up type power stage to incite somebody to action to provide control signal
Input voltage is converted to output voltage, and the step-down/up type power stage includes inductance and at least two switch connections inductance, its
It is characterised by that the control method comprises the following steps：
A, the detection output voltage produce feedback signal；
B, the difference amplified between the feedback signal and a reference voltage produce the first error signal；
C, provided according to first detection signal and thermal compensation signal and determine the first signal；
D, first error signal is compensated according to the thermal compensation signal produce the second error signal；
E, first signal is triggered according to enable signal；And
F, according to second error signal and the first signal deciding control signal.
10. control method as claimed in claim 9, it is characterised in that the first detection signal and the input voltage, defeated
The variable quantity wherein at least one for going out voltage, the inductive current by the inductance and the output voltage is related.
11. control methods as claimed in claim 9, it is characterised in that step C includes：
The first detection signal is converted to into the thermal compensation signal；And
The thermal compensation signal is converted to into first signal.
12. control methods as claimed in claim 9, it is characterised in that step D includes：
The first error signal produces first voltage according to the thermal compensation signal partial pressure；
The first voltage is converted to into electric current to a resistance to produce a second voltage；And
First error signal is adjusted by the second voltage.
13. control methods as claimed in claim 9, it is characterised in that step F includes：
Comparison second error signal and a sawtooth signal produce the first comparison signal；
Comparison first signal and sawtooth signal produce the second comparison signal；And
The control signal is produced according to described first and second comparison signal.
14. control methods as claimed in claim 9, it is characterised in that further include and institute is produced according to the first detection signal
State enable signal.
15. control methods as claimed in claim 9, it is characterised in that further include and institute is produced according to first error signal
State enable signal.
16. control methods as claimed in claim 9, it is characterised in that further include according to the second detection signal strangulation
The level of one error signal, second detection signal and the input voltage, output voltage and the inductance by the inductance
Electric current wherein at least one is related.
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| CN200910209285.9A CN102055334B (en) | 2009-10-28 | 2009-10-28 | Control circuit and method for buck-boost power supply converter |
| CN201410147913.6A CN103973113B (en) | 2009-10-28 | 2009-10-28 | Control circuit and method for buck-boost power converter |
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| CN105048811B (en) * | 2015-08-17 | 2017-06-09 | 西安交通大学 | The fixed frequency of ON time correction of DC DC converters is across period controller and method |
| CN108183611B (en) * | 2017-12-26 | 2019-12-06 | 成都芯源系统有限公司 | control device and method of bidirectional switch circuit |
| TWI740650B (en) * | 2020-09-17 | 2021-09-21 | 國立臺灣科技大學 | Dual mode buck converter |
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