CN104901556A - Synchronous rectification control method for programmable dead time and synchronous rectification controller - Google Patents
Synchronous rectification control method for programmable dead time and synchronous rectification controller Download PDFInfo
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Abstract
The invention provides a synchronous rectification control method for programmable dead time and a synchronous rectification controller. The synchronous rectification control method provided in the embodiment comprises the following steps: providing the synchronous rectification controller which has a first pin; sampling a pin voltage of the first pin to generate a sampling voltage; after the sampling voltage is generated, providing a detection current which flows through the first pin from the synchronous rectification controller; and generating a plurality of digital dead time control signals according to the sampling voltage and the pin voltage, and controlling a rectification switch according to the dead time control signals to determine the dead time of the rectification switch.
Description
Technical field
The present invention is broadly directed to control method and the controller of the synchronous rectification of power supply unit.
Background technology
Power supply unit is except requiring accurately except output voltage or output current, and energy conversion efficiency (power conversion efficiency) is also often one of specification of lying in very much of industry.
Fig. 1 is a known flyback (flyback) switch type power supplying device 10, as an example of switch type power supplying device.When Pwm controller 14 makes power switch 20 conducting, input power V
iNtransformer 18 energy storage is made with input ground 26; When power switch 20 is closed, transformer 18 is released energy by rectifier diode 12 pairs of output capacitances 17 and load 16, (has output voltage V to set up out-put supply OUT
oUT) and export ground 28.By suitable feedback path, Pwm controller 14 can work period (duty cycle) of Modulating Power switch 20, makes out-put supply OUT meet the specification wanted.
All transformers 18 output to the secondary side current I of output capacitance 17 and load 16
sEC, all must pass through rectifier diode 12.The forward bias voltage drop of rectifier diode 12 is approximately 1V, consumes energy regularly.In order to reduce the energy dissipation of rectifier diode 12, increasing energy conversion efficiency, so in known technology, as shown in Figure 2, having developed and replaced rectifier diode 12 with a rectifier switch 24.Such technology is called synchronous rectification (synchronous rectification, SR).Rectifier switch 24 in switch type power supplying device 30 needs to be properly controlled, and imitates the action of the rectifier diode 12 in Fig. 1.When power switch 20 conducting, transformer 18 energy storage, rectifier switch 24 is closed.When transformer 18 be in discharge condition release can time, rectifier switch 24 conducting, provides the discharge path of a low resistance low power consuming, allows transformer 18 pairs of output capacitances 17 charge.When after transformer 18 discharge off, rectifier switch 24 also needs to close, and prevention out-put supply OUT is to transformer 18 energy storage.
Generally speaking, before transformer 18 does not also have discharge off, rectifier switch 24 just needs to close, and can prevent aircraft bombing.In this description, rectifier switch 24 to the complete discharge off of transformer 18 during this period of time, is called dead time (dead time) T after closing
dEAD.Dead time T
dEADneed the control of extreme care.If dead time is oversize, just can not get the benefit reducing energy dissipation.If dead time becomes negative value, mean that power switch 20 just switches to conducting, then switch type power supplying device 30 has the danger of aircraft bombing just in case rectifier switch 24 is also when the opening time.Along with system is different, dead time T
dEADdemand also often different, therefore, dead time T
dEADpreferably can be set by system manufacturer, can programme.
When the synchronous rectifying controller controlling rectifier switch 24 with integrated circuit in current, how making the number of pins of synchronous rectifying controller minimized, provide appropriate programmable dead time simultaneously, is the problem that industry is made great efforts.
Summary of the invention
Embodiment provides a kind of synchronous rectification control method, includes: provide a synchronous rectifying controller, and it has one first pin; One pin voltage of sampling on this first pin, to produce a sampled voltage; After this sampled voltage of generation, a detection electric current is provided, from this synchronous rectifying controller, flows out this first pin; According to this sampled voltage and this pin voltage, produce control signal dead time of several numeral, and according to these of control signal, control a rectifier switch, to determine a dead time of this rectifier switch dead time.
Embodiment provides a kind of synchronous rectifying controller, in order to control a rectifier switch.This synchronous rectifying controller includes one first pin, a current source, a sample circuit, an error amplifier and an analog-digital converter.This current source optionally provides a detection electric current, flows out this first pin.This sample circuit is connected to this first pin, in order to a pin voltage of sampling on this first pin, to produce a sampled voltage.This error amplifier framework, when this detection electric current is provided, according to this pin voltage and sampled voltage, produces the error signal of a simulation.This error signal is converted to control signal dead time of several numeral by this analog-digital converter framework.These, control signal can determine a dead time of this rectifier switch dead time.
Embodiment
In this manual, have the symbol that some are identical, it represents the element with identical or similar structure, function, principle, and those skilled in the art can know by inference according to the instruction of this specification.For the succinct degree of specification is considered, the element of identical symbol will no longer repeat.
Although this specification is using a flyback switch type power supplying device as an embodiment, the present invention is not limited to this.For example, present invention may also be implemented in step-down (buck) power supply unit, booster power supply (booster) or falling-rising voltage source supply (buck-booster).
Fig. 3 is a flyback switch type power supplying device 40 of sequentially one embodiment of the invention, and it has a synchronous rectifying controller 42, controls rectifier switch 24.In this embodiment, synchronous rectifying controller 42 is a packaged integrated circuit, has pin SYN, DRV, VCC, EN/DT and GND.Be not used for limiting in Fig. 3 of the present invention, rectifier switch 24 is to have the PMOS transistor of a parasitic body diode (bodydiode) 37 for example.Body diode 37 is connected between the body pole (body) of rectifier switch 24 and drain electrode (drain).The pin VCC of synchronous rectifying controller 42 is connected to the rectified out-put supply OUT of rectifier switch 24, is also the source electrode (source) of rectifier switch 24.The pin SYN of synchronous rectifying controller 42, by detecting resistance 39, is connected to the drain electrode (drain) of rectifier switch 24.The source short of rectifier switch 24 is to body pole.The pin GND of synchronous rectifying controller 42 is connected to and exports ground 28.
The pin EN/DT of synchronous rectifying controller 42 is a multifunctional pin, can provide two kinds of functions of activation and setting dead time.Resistance 90 and 92 is connected in series with output voltage V
oUTand export between ground 28, and pin EN/DT is the tie point between resistance 90 and 92.The resistance value of suitable selection resistance 90 and 92, approximately can set condition and the dead time of synchronous rectifying controller 42 activation.
Partial circuit in synchronous rectifying controller 42 in Fig. 4 exemplary graph 3 and resistance 90 and 92.
Comparator 108 compares the pin voltage V on pin EN/DT
eNDTwith a reference voltage V
rEF, enable signal S is provided according to this
eN-BIAS.As pin voltage V
eNDTexceed reference signal V
rEFtime, enable signal S
eN-BIASactivation, synchronous rectifying controller 42 just starts to make inner circuit working, provides suitable sequential.For example, at enable signal S
eN-BIASafter activation, synchronous rectifying controller 42 first carries out inside T dead time
dEADsetting, then just start switch synchronous rectification switch 24.
Current source 102 provides detection electric current I
sET.As signal S
bIASactivation, during switch 104 conducting, detects electric current I
sETpin EN/DT can be flowed out, become electric current I
b, draw high pin voltage V
eNDT.
Sample circuit 106 is at signal S
bIASforbidden energy, when switch 105 cuts out, sampled voltage V
sPLcan be pin voltage V
eNDTa sampled result.
The resistance of operational amplifier 110 and periphery can form an error amplifier.Sampled voltage V
sPLwith pin voltage VENDT
-difference, by by the amplification of ratio, produce the error signal VENDT_SEN of simulation.
Analog-digital converter 112 can convert error signal VENDT_SEN to several digital signal DB0, DB1 and DB2.Several latch cicuit can latched digital signal DB0, DB1 and DB2, produces control signal DTB0 dead time, DTB1 and the DTB2 of numeral.In one embodiment, after dead time, control signal produced, electric current I is detected
sETcan stop.In one embodiment, as inside T dead time
dEADsetting complete after, dead time control signal DTB0, DTB1 and DTB2 remains unchanged.
The resistance value of variable resistor 114 by dead time control signal DTB0, DTB1 and DTB2 determined, as shown in Figure 4.
Fig. 5 is a signal waveforms, is relevant to some signals in Fig. 4.
At time started t
sTART, along with output voltage V
oUTrising, pin voltage V
eNDTexceed reference voltage V
rEF, so enable signal S
eN-BIASbecome activation.Synchronous rectifying controller 42 is enabled, so sequentially create sampling periods T
sAMPLEand setting period T
sET.
At sampling periods T
sAMPLEin, signal S
sAMPLEactivation, signal S
bIASforbidden energy, detects electric current I
sETpin EN/DT cannot be flowed out.Now, pin voltage V
eNDTapproximately and output voltage V
oUTproportional, and sampled voltage VSPL approximates pin voltage VENDT greatly.Also therefore, error signal VENDT_SEN is approximately 0.For example, now pin voltage V
eNDT=V
oUT* R
92/ (R
90+ R
92), wherein R
90with R
92be respectively the resistance value of resistance 90 and 92.
At setting period T
sETin, signal S
sAMPLEforbidden energy, signal S
bIASactivation.Now, electric current I is detected
sETflow out pin EN/DT, so pin voltage V
eNDTlarge appointment equals V
oUT* R
92/ (R
90+ R
92)+I
sET* (R
92|| R
90), wherein, R
92|| R
90represent the resistance value that resistance 90 is in parallel with 92.Because signal S
sAMPLEforbidden energy, so sampled voltage V
sPLroughly constant, equal V
oUT* R
92/ (R
90+ R
92).Error signal V
eNDT_SENi will be approximated greatly
sET* (R
92|| R
90) * K, the voltage gain (voltage gain) of the error amplifier that the resistance that wherein K is operational amplifier 110 and periphery is formed.Now digital signal DB0, DB1 and DB2 can reflect the Analog-digital Converter result of error signal VENDT_SEN, but because the obstruct of latch cicuit, dead time control signal DTB0, DTB1 and DTB2 maintains with sampling periods T
sAMPLEin the same state.
At setting period T
sETafterwards, signal S
sAMPLEactivation, signal S
bIASforbidden energy.Therefore, electric current I is detected
sETstop flowing out pin EN/DT.Pin voltage V
eNDTapproximately and output voltage V
oUTproportional, and sampled voltage V
sPLapproximate pin voltage V greatly
eNDT.Signal S
sAMPLErising edge make latch circuit latches digital signal DB0, DB1 and DB2, produce dead time control signal DTB0, DTB1 and DTB2.In one embodiment, after dead time, control signal produced, electric current I is detected
sETcan stop.As shown in Figure 5.Dead time control signal DTB0, DTB1 and DTB2 determines the resistance value of variable resistor 114.At setting period T
sETafterwards, if output voltage V
oUTlower than reference signal V
rEF, comparator 108 just can forbidden energy synchronous rectifying controller 42 according to this.
At setting period T
sETafterwards, synchronous rectifying controller 42 according to variable resistor 114, control synchronization rectifier switch 24.Variable resistor 114 determines the opening time (On time) of synchronous rectification switch 24, also determines T dead time of synchronous rectification switch 24 simultaneously
dEAD.Therefore, dead time T
dEADroughly be associated with I
sET* (R
92|| R
90) * K.System manufacturer can select suitable resistance 90 and 92, sets T dead time
dEAD.
Known according to above analysis, pin EN/DT is a multifunctional pin.As long as select suitable resistance 90 and 92, just output voltage V can be determined
oUTwhen can activation synchronous rectifying controller 42, and dead time T
dEADdesired value.
Fig. 6 shows the control method implemented according to the present invention, and it illustrates please refer to Fig. 4 and Fig. 5.
Step 140 confirms pin voltage V
eNDTexceed reference signal V
rEF, so activation synchronous rectifying controller 42.
In step 142, pin voltage V
eNDTbe sampled, institute to produces sampled voltage V
sPL.
Step 144 provides detection electric current I
sET, make it flow out pin EN/DT.Therefore, pin voltage V
eNDTcan be driven high, become with sampled voltage V
sPLdifferent.
Step 146 is according to pin voltage V
eNDTwith sampled voltage V
sPLdifference, produce error signal V
eNDT_SEN.Error signal V
eNDT_SENdigital conversion results, be latched in step 148, and produce control signal DTB0 dead time, DTB1 and DTB2.
Step 150 makes detection electric current I
sETno longer flow out pin EN/DT.
Step 152 according to dead time control signal DTB0, DTB1 and DTB2, determine the resistance value of variable resistor 114, so determine the opening time (On time) of synchronous rectification switch 24, also determine T dead time of synchronous rectification switch 24 simultaneously
dEAD.
Fig. 7 shows in synchronous rectifying controller 42, about the opening time control circuit of rectifier switch 24, as an example, illustrates how variable resistor 114 affects T dead time
dEAD.
Sequential generator 44 is according to the output voltage V on pin VCC
oUTwith the voltage V on pin SYN
sYN, provide along bias voltage signal S
nB, initial signal S
iNI, and update signal S
uPD.Discharge time, register 46 provided time signal V instantly
rEAL, it approximately represents that body diode 37 was in along time during bias voltage, and it is approximately secondary side current I
sECbeing greater than the time of zero, also can be approximately T discharge time of transformer 18 pairs of output capacitances 17
dIS.Record electric capacity 50
bestimated time signal V is provided
qUESS.Updating device 47 is at T discharge time
dISafter a Preset Time (will explain after a while), according to time signal V instantly
rEALupgrade estimated time signal V
qUESS, make it approach time signal V instantly
rEAL.Comparator 62 and logical circuit 60 can be considered as an on-off controller, according to estimated time signal V
qUESSand voltage V
rAISED, produce signal S at pin DRV
dRV, control rectifier switch 24.
Estimated time signal V
qUESSrepresentative be body diode 37 in this switch periods, discharge time T
dISa conjecture value.To explain after a while, in this embodiment, estimated time signal V
qUESSthe meeting time point deciding rectifier switch 24 closedown, and estimated time signal V
qUESScan along with the increase of switch periods, rapidly toward T real discharge time
dISapproach.
Fig. 8 is some signal timing diagrams in Fig. 7, in order to some the possible operations in key-drawing 7.Please refer to the switch type power supplying device 40 of Fig. 3.
The uppermost waveforms stands output voltage V of Fig. 8
oUTto secondary-side voltage V
sECvoltage difference.At time point t
0, because the power switch in Fig. 3 20 transfers closedown to, secondary-side voltage V
sECstart to exceed output voltage V
oUT, sequential generator 44 provides a pulse as initial signal S
iNI.As secondary-side voltage V
sECbe greater than output voltage V
oUTtime, body diode 37 is in along bias voltage, along bias voltage signal S
nBfor 1 in logic; Contrary, when body diode 37 is in reverse blas, along bias voltage signal S
nBfor 0 in logic.Along bias voltage signal S
nBbe the period of 1, T discharge time can be referred to as
dIS, as shown in Figure 8.In fig. 8, in time point t
4, body diode 37 becomes reverse blas, so along bias voltage signal S
nBtransfer 0 in logic to, declaration T discharge time
dISend.In time point t
4after time point t
5, sequential generator 44 provides another pulse as update signal S
uPD.
At time point t
0, because initial signal S
iNIpulse, switch 53 will time signal V instantly
rEALreset to 0V.At time point t
1, initial signal S
iNIend-of-pulsing.Time point t
0to t
1between period, a starting time (initial time) can be called.
At time point t
1, voltage current adapter 56 is according to pin voltage V
eNDT, produce charging current I
cHG, by variable resistor 114, start to charge to electric capacity 52, produce time signal V instantly in one end of electric capacity 52
rEAL.Instantly time signal V
rEALcan along with T discharge time
dISincrease and rise, until discharge time T
dISterminate.Therefore, time signal V instantly
rEALa ramp signal can be considered as.At time point t
4afterwards, time signal V instantly
rEALmaintain its peak value, which represent body diode 37 in this switch periods, be in the period along bias state, namely discharge time T
dIS.
As shown in Figure 7, voltage V
rAISEDwith time signal V instantly
rEAL, represent the voltage at the two ends of variable resistor 114 respectively.At suitable bias voltage signal S
nBfor in logic 1 time because charging current I
cHGflow through variable resistor 114, so voltage V
rAISEDtime signal V instantly can be greater than
rEAL, as shown in Figure 8.Relative to time signal V instantly
rEAL, voltage V
rAISEDcan be considered a boost signal.Variable resistor 114 can be considered as a bias voltage supplier, provides a bias voltage (offset voltage) respectively, adds to time signal V instantly
rEAL, produce voltage V
rAISED.And the size of this bias voltage, be controlled by control signal DTB0 dead time, DTB1 and DTB2.
At time point t
1, due to initial signal S
iNIend-of-pulsing, starter 58 can arrange the set-reset flip-floop in (set) logical circuit 60, makes signal S
dRVstart as 1 in logic, as shown in Figure 8.In this embodiment, because rectifier switch 24 is a PMOS transistor, so signal S
dRVfor in logic 1 time, signal S
dRVbe a relative low-voltage, rectifier switch 24 conducting; As signal S
dRVfor in logic 0 time, signal S
dRVbe a relative high voltage, rectifier switch 24 is closed.Rectifier switch 24 conducting can make output voltage V
oUTto secondary-side voltage V
sECthe reduction that both difference is unexpected.Fig. 5 also show reference signal V
dS-NO-SYNC, when it represents that rectifier switch 24 does not have a conducting, right output voltage V
oUTto secondary-side voltage V
sECbetween difference.
At time point t
2, voltage V
rAISEDexceed estimated time signal V
qUESS, so the set-reset flip-floop in (reset) logical circuit 60 reseted by comparator 62, make signal S
dRVbecome 0 in logic, rectifier switch 24 is closed.Output voltage V
oUTto secondary-side voltage V
sECdifference, be now returned to reference signal V
dS-NO-SYNCthe same.In simple terms, as estimated time signal V
qUESSwith time signal V instantly
rEALdifference, during the bias voltage provided lower than variable resistor 114, rectifier switch 24 is closed.
Time point t
2to t
4between period, indicating as Fig. 8, is T dead time
dEAD.
At time point t
5, update signal S
uPDthe first closing switch 48 of pulse
a, then actuating switch 48
b.Therefore, when switch 48
aduring closedown, electric capacity 50
atime signal V instantly can be remembered in advance
rEAL.At switch 48
bduring conducting, because electric capacity 50
awith 50
bshort circuit each other, so there occurs charge share (charge sharing), estimated time signal V
qUESStherefore be updated.For example, if electric capacity 50
awith 50
bcapacitance approximately equal.Estimated time signal V after renewal
qUESSlarge appointment equals the estimated time signal V before upgrading
qUESSwith time signal V instantly
rEALaverage, as shown in Figure 8.In simple terms, V
qUESS=w
*v
qUESS+ (1-w) * V
rEAL, wherein w is the ratio value between 0 and 1, by electric capacity 50
awith 50
bcapacitance determined.
At time point t
6, the power switch 20 in Fig. 3 transfers closedown to once again, so initial signal S
iNIpulse occur, along bias voltage signal S
nBtransfer 1 in logic to.Time point t
0to t
6period before, a switch periods can be considered as.At time point t
6switch periods afterwards, estimated time signal V
qUESSalso be updated, continue past time signal V instantly
rEALapproach, as shown in Figure 8.
From the explanation of above circuit operation, often through a switch periods, estimated time signal V
qUESSmay in the mode of charge share, past time signal V instantly
rEALpeak value approach.The mode of approaching like this will make estimated time signal V very fast
qUESSvery close time signal V instantly
rEAL.The bias voltage that variable resistor 114 provides, can make signal S
dRVin time before body diode 37 becomes reverse blas, just close synchronous rectification switch 24, increase the energy conversion efficiency of synchronous rectification.Therefore, variable resistor 114 determines the opening time end point of synchronous rectification switch 24, so also determine T dead time
dEAD.The bias voltage that theres is provided of variable resistor 114 is provided, also compares and can not be subject to the change such as processing procedure, temperature and affected.The resistance value of variable resistor 114, as previously described, can be programmed by resistance 90 and 92.
When stable state (load 16 is constant for a long time), dead time T
dEADlength, be determined by the resistance value of variable resistor 114.
The foregoing is only the preferred embodiments of the present invention, all equalizations done according to claims of the present invention change and modify, and all should belong to covering scope of the present invention.
Accompanying drawing explanation
Fig. 1 is a known flyback switch type power supplying device.
Fig. 2 is a known synchronous rectified power supply.
Fig. 3 is a flyback switch type power supplying device of sequentially one embodiment of the invention.
Partial circuit in synchronous rectifying controller 42 in Fig. 4 exemplary graph 3 and resistance 90 and 92.
Fig. 5 is a signal waveforms, is relevant to some signals in Fig. 4.
Fig. 6 shows the control method implemented according to the present invention.
Fig. 7 shows in synchronous rectifying controller 42, about the opening time control circuit of rectifier switch 24.
Fig. 8 is some signal timing diagrams in Fig. 7.
[symbol description]
10 switch type power supplying devices
12 rectifier diodes
14 Pwm controllers
16 loads
17 output capacitances
18 transformers
20 power switchs
24 rectifier switchs
26 input ground
28 export ground
30 switch type power supplying devices
37 body diodes
39 detect resistance
40 switch type power supplying devices
42 synchronous rectifying controllers
44 sequential generators
46 discharge time register
47 updating devices
48
a, 48
bswitch
50
aelectric capacity
50
brecord electric capacity
52 electric capacity
53 switches
56 voltage current adapters
58 starters
60 logical circuits
62 comparators
90,92 resistance
102 current sources
104 switches
105 switches
106 sample circuits
108 comparators
110 operational amplifiers
112 analog-digital converters
114 variable resistors
140,142,144,146,148,150,152 steps
DB0, DB1, DB2 digital signal
DRV pin
DTB0, DTB1, DTB2 control signal dead time
EN/DT pin
GND pin
I
cHGcharging current
I
sECsecondary side current
I
sETdetect electric current
OUT out-put supply
S
bIASsignal
S
dRVsignal
S
eN-BIASenable signal
S
iNIinitial signal
S
nBalong bias voltage signal
S
sAMPLEsignal
S
uPDupdate signal
SYN pin
T
sTARTtime started
T
0, t
1, t
2, t
4, t
5, t
6time point
T
dEADdead time
T
dISdischarge time
T
sAMPLEsampling periods
T
sETthe setting period
VCC pin
V
dS-NO-SYNCreference signal
V
eNDTpin voltage
V
eNDT_SENerror signal
V
qUESSestimated time signal
V
iNinput power
V
oUToutput voltage
V
rAISEDvoltage
V
rEALinstantly time signal
V
rEFreference voltage
V
sECsecondary-side voltage
V
sPLsampled voltage
V
sYNvoltage
Claims (12)
1. a synchronous rectification control method, includes:
There is provided a synchronous rectifying controller, it has one first pin;
One pin voltage of sampling on this first pin, to produce a sampled voltage;
After this sampled voltage of generation, a detection electric current is provided, from this synchronous rectifying controller, flows out this first pin;
According to this sampled voltage and this pin voltage, produce control signal dead time of several numeral; And
According to control signal described dead time, control a rectifier switch, to determine a dead time of this rectifier switch.
2. synchronous rectification control method as claimed in claim 1, wherein, this first pin is a multifunctional pin, and this control method also includes:
Before this detection electric current is provided, when this pin voltage is more than a reference voltage, this synchronous rectifying controller of activation.
3. synchronous rectification control method as claimed in claim 1, includes:
Relatively this sampled voltage and this pin voltage, to produce the error signal of a simulation;
Convert this error signal to several digital signal; And
Latch described digital signal, to produce control signal described dead time.
4. synchronous rectification control method as claimed in claim 1, includes:
According to control signal described dead time, control a variable resistor;
Wherein, this variable resistor is decided this dead time by framework.
5. synchronous rectification control method as claimed in claim 4, includes:
One charging current is provided, flows through this variable resistor, to a capacitor charging, to produce a ramp signal and a boost signal respectively at these variable-resistance two ends;
When this rectifier switch is closed, upgrade an estimated time signal with this ramp signal; And
Determine an opening time of this rectifier switch according to this estimated time signal and this boost signal, thus determine this dead time.
6. synchronous rectification control method as claimed in claim 1, wherein, when this detection electric current stops, the about ratio of this pin voltage is at the output voltage after this rectifier switch rectification.
7. synchronous rectification control method as claimed in claim 1, wherein, after control signal dead time of this numeral produces, stops this detection electric current.
8. a synchronous rectifying controller, in order to control a rectifier switch, includes:
One first pin;
One current source, optionally provides a detection electric current, flows out this first pin;
One sample circuit, is connected to this first pin, in order to a pin voltage of sampling on this first pin, to produce a sampled voltage;
One error amplifier, framework, when this detection electric current is provided, according to this pin voltage and sampled voltage, produces the error signal of a simulation; And
One analog-digital converter, this error signal is converted to control signal dead time of several numeral by framework;
Wherein, described dead time, control signal can determine one of this rectifier switch dead time.
9. synchronous rectifying controller as claimed in claim 8, wherein, this analog-digital converter converts this error signal to several digital signal, and latches described digital signal, to produce this of control signal dead time.
10. synchronous rectifying controller as claimed in claim 8, order includes:
One variable resistor, is controlled by control signal described dead time.
11. synchronous rectifying controllers as claimed in claim 8, include:
One opening time controller, framework produces a ramp signal and a boost signal, includes a variable resistor, is controlled by control signal described dead time;
Wherein, this variable resistor can determine the difference between this ramp signal and this boost signal.
12. synchronous rectifying controllers as claimed in claim 11, wherein, this opening time controller includes:
One charging current source and an electric capacity, this variable resistor is connected between this charging current source and this electric capacity, and these variable-resistance two ends provide this ramp signal and this boost signal respectively;
One refresh circuit, when this rectifier switch is closed, upgrades an estimated time signal with this ramp signal; And
One comparator, compares this estimated time signal and this ramp signal, to determine an opening time of this rectifier switch, thus determines this dead time of this rectifier switch.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108390568A (en) * | 2018-04-13 | 2018-08-10 | 成都矽芯科技有限公司 | A kind of synchronous rectification BOOST type power supply modulator circuits using low pressure PMOS rectifying tubes |
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| JPH07274494A (en) * | 1994-04-01 | 1995-10-20 | Oki Electric Ind Co Ltd | Switching power circuit of synchronous commutating circuit |
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| DE102009001531A1 (en) * | 2008-03-13 | 2009-09-17 | Infineon Technologies Austria Ag | Rectifier circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108390568A (en) * | 2018-04-13 | 2018-08-10 | 成都矽芯科技有限公司 | A kind of synchronous rectification BOOST type power supply modulator circuits using low pressure PMOS rectifying tubes |
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| CN104901556B (en) | 2017-07-21 |
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