CN203445774U - Peak value current deviation generation circuit, peak value current sample hold circuit with compensation, constant current control circuit and switch power source - Google Patents
Peak value current deviation generation circuit, peak value current sample hold circuit with compensation, constant current control circuit and switch power source Download PDFInfo
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- CN203445774U CN203445774U CN201320466246.9U CN201320466246U CN203445774U CN 203445774 U CN203445774 U CN 203445774U CN 201320466246 U CN201320466246 U CN 201320466246U CN 203445774 U CN203445774 U CN 203445774U
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Abstract
The utility model provides a peak value current deviation generation circuit, a peak value current sample hold circuit with compensation, a constant current control circuit and a switch power source; the peak value current deviation generation circuit comprises an interval given time sample hold circuit and an estimation peak value sampling deviation circuit connected with the interval given time sample hold circuit; the peak value current sample hold circuit with compensation comprises a peak value sample hold circuit, the peak value current deviation generation circuit and a real peak value calculation circuit or a voltage reference adjusting circuit connected with the peak value current deviation generation circuit; the constant current control circuit comprises the peak value current sample hold circuit with compensation, an output equivalent current calculation circuit, an error amplifier, a PWM signal generation circuit, and a logic and driving circuit; the switch power source comprises the constant current control circuit and a main circuit coupled with the constant current control circuit. The peak value current deviation generation circuit, the peak value current sample hold circuit with compensation, the constant current control circuit and the switch power source can solve the problem of poor constant current accuracy caused by inaccuracy of peak value current sample hold.
Description
Technical field
The utility model relates to switch power technology, relates in particular to peak current sampling hold circuit, constant-current control circuit and Switching Power Supply that a kind of peak current deviation produces circuit, band compensation.
Background technology
With reference to figure 1, Fig. 1 shows the circuit structure that traditional peak sampling hold circuit is applied to the output constant current control of buck configuration, comprises control circuit 100, sustained diode 1, power switch M1, sampling resistor Rcs, inductance L 1 and output capacitance C1.Wherein, control circuit 100 comprises: peak sampling hold circuit 106, and during power switch M1 conducting, sample streams is the sampled voltage Vcs on sampling resistor Rcs through the peak current of power switch M1; Output equivalent Current calculation circuit 105, according to the peak value of the sampled voltage Vcs on sampling resistor Rcs, calculates the equivalent voltage that output equivalent electric current output represent this output equivalent electric current; Error amplifier 101, does error amplification by this equivalent voltage and fiducial value Vref1, and output error signal Vcomp is to loop compensation port COMP; Loop compensation port COMP, this loop compensation port COMP can additional compensating element,, generally resistance, electric capacity connection in series-parallel, consists of, and the error signal Vcomp being exported by error amplifier 101 carrys out control loop; Pwm signal generation circuit 102, receives error signal Vcomp, produces pwm signal and exports logic control circuit 103 to, and the duty ratio of this pwm signal is relevant to error signal Vcomp; Logic control circuit 103 produces pre-drive signal GT1, and this pre-drive signal GT1 produces and drives signal GT driving power switch M1 through drive circuit 104.
Furthermore, in the circuit structure shown in Fig. 1, the precision of output current Iout is relevant, also relevant to the precision of error amplifier 101 to the peak value sampling retention value that fiducial value Vref1, peak sampling hold circuit 106 produce.When peak value sampling retention value and true peak have deviation, can cause output current Iout deviation, therefore need to improve as far as possible the precision of peak value sampling value.
With reference to figure 2, the peak value sampling of prior art keeps in sequential, if directly adopt the gate drive signal GT of power switch as sampled signal, due to the delay distortion of inner sampling switch, the moment that can cause actual sampled signal to start to decline at peak current just samples, now just cannot correctly sample peak current, cause circuit unstable, therefore generally with pre-drive signal GT1, carry out sampled peak electric current.Between the gate drive signal GT of pre-drive signal GT1 and power switch M1, there is Td time of delay, thereby cause the peak current sampled voltage Vcsa that samples and actual peak current voltage Vcspk to have deviation delta Vcs.With this, be with peak current sampled voltage Vcsa devious to control output constant current and also just will inevitably cause deviation.Wherein, the expression formula of deviation delta Vcs is:
Wherein, L
1for the inductance value of inductance L 1, V
inrepresent input voltage, V
outfor output voltage.R
csfor the resistance value of sampling resistor Rcs, T
drepresent the time that sample in advance time of delay in other words.
As T time of delay
d, inductance L 1 inductance value L
1, input voltage V
in, output voltage V
outin any one while changing, deviation delta Vcs can change, the output current value being calculated by peak current sampled value will change.Thereby cause constant-current characteristics poor.
Switching Power Supply shown in Fig. 1, by the peak current of sample streams overpower switch M1, has realized output constant current control, and circuit is simple, cost is lower, but also has corresponding shortcoming.Because the peak current of sampling is not accurate enough, cause the output current value of control and the value of requirement to have deviation, and input voltage and output voltage are when change, output current value also can change, be that load regulation and output linearity regulation are bad, the constant-current characteristics of circuit is good not, and the precision that constant current is controlled is not enough.
Utility model content
The technical problems to be solved in the utility model is to provide peak current sampling hold circuit, constant-current control circuit and the Switching Power Supply that a kind of peak current deviation produces circuit, band compensation, can solve peak current sampling and keep the poor problem of constant current accuracy inaccurate and that cause.
For solving the problems of the technologies described above, the utility model provides a kind of peak current deviation to produce circuit, comprising:
Interval given time sampling hold circuit, keeps peak current according to Preset Time interval sampling, and this Preset Time interval becomes preset ratio with peak sampling hold circuit to the sampling time that shifts to an earlier date of described peak current;
Estimation peak value sampling bias circuit, the peak current obtaining according to described interval given time sampling hold circuit calculates the peak current deviation in described Preset Time interval, and estimates that according to the peak current deviation in described Preset Time interval and described preset ratio this peak sampling hold circuit is due to the peak current deviation of sampling and causing in advance.
According to an embodiment of the present utility model, described interval given time sampling hold circuit comprises:
The first switch, its first end receives sampled voltage, and its control end receives the first sampling pulse;
The first electric capacity, its first end connects the second end of described the first switch, its second end ground connection;
The first voltage follower, its input connects the first end of described the first electric capacity;
Second switch, its first end receives sampled voltage, and its control end receives the second sampling pulse, and the delay between described the second sampling pulse and described the first sampling pulse equals described Preset Time interval;
The second electric capacity, its first end connects the second end of described second switch, its second end ground connection;
Second voltage follower, its input connects the first end of described the second electric capacity;
The 3rd switch, its first end connects the output of described the first voltage follower, and its control end receives the inversion signal that drives signal;
The 4th switch, its first end connects the output of described second voltage follower, and its control end receives the inversion signal of described driving signal;
The 3rd electric capacity, its first end connects the second end of described the 3rd switch, its second end ground connection;
The 4th electric capacity, its first end connects the second end of described the 4th switch, its second end ground connection.
The utility model also provides a kind of peak current sampling hold circuit with compensation, comprising:
Above-described peak sampling hold circuit and peak current deviation produce circuit;
Real peak counting circuit, the peak current that the peak current deviation of using described peak current deviation generation circuit to obtain obtains described peak sampling hold circuit compensates, and determines real peak current.
The utility model also provides a kind of constant-current control circuit, comprising:
The peak current sampling hold circuit of above-mentioned band compensation;
Output equivalent Current calculation circuit, is connected with described real peak counting circuit, calculates the equivalent voltage of output equivalent electric current this output equivalent electric current of output expression according to described real peak current;
Error amplifier, its first input end receives the equivalent voltage that described output equivalent Current calculation circuit produces, and its second termination is received reference voltage, and its output produces error signal;
Pwm signal generation circuit, receives the error signal of described error amplifier output, and produces pwm signal according to this error signal;
Logic and driver circuitry, receives the pwm signal of described pwm signal generation circuit output, and produces and drive signal according to this pwm signal, and described driving signal is for the turn-on and turn-off of driving power switch.
The utility model also provides a kind of peak current sampling hold circuit with compensation, comprising:
Above-described peak sampling hold circuit and peak current deviation produce circuit;
Reference voltage regulating circuit, produces according to described peak current deviation the peak current deviation that circuit obtains default reference voltage is regulated, the reference voltage after adjusted.
The utility model also provides a kind of constant-current control circuit, comprising:
The peak current sampling hold circuit of above-mentioned band compensation;
Output equivalent Current calculation circuit, peak sampling hold circuit in the peak current sampling hold circuit compensating with described band is connected, and the peak current obtaining according to described peak sampling hold circuit calculates the equivalent voltage of output equivalent electric current this output equivalent electric current of output expression;
Error amplifier, its first input end receives the equivalent voltage that described output equivalent Current calculation circuit produces, its second termination is received the reference voltage after the adjusting that the reference voltage regulating circuit in the peak current sampling hold circuit of described band compensation produces, and its output produces error signal;
Pwm signal generation circuit, receives the error signal of described error amplifier output, and produces pwm signal according to this error signal;
Logic and driver circuitry, receives the pwm signal of described pwm signal generation circuit output, and produces and drive signal according to this pwm signal, and described driving signal is for the turn-on and turn-off of driving power switch.
The utility model also provides a kind of Switching Power Supply, comprising:
Above-described constant-current control circuit;
Main circuit with described constant-current control circuit coupling.
According to an embodiment of the present utility model, described main circuit is buck configuration.
According to an embodiment of the present utility model, this main circuit comprises:
Fly-wheel diode, its negative pole connects Input voltage terminal;
Power switch, its first end connects the positive pole of described fly-wheel diode, and its control end receives the driving signal that described constant-current control circuit produces, and its second end is connected with the input of the peak current sampling hold circuit of band compensation in described constant-current control circuit;
Sampling resistor, its first end connects the second end of described power switch, its second end ground connection;
Inductance, its first end connects the positive pole of described fly-wheel diode;
Output capacitance, its first end connects the negative pole of described fly-wheel diode, and its second end connects the second end of described inductance.
According to an embodiment of the present utility model, described main circuit is inverse-excitation type structure.
According to an embodiment of the present utility model, this main circuit comprises:
Transformer, the Same Name of Ends of its former limit winding receives input voltage;
Fly-wheel diode, its anodal different name end that connects the secondary winding of described transformer, the Same Name of Ends ground connection of described secondary winding;
Power switch, its first end connects the different name end of the former limit winding of described transformer, its control end receives the driving signal that described constant-current control circuit produces, and its second end is connected with the input of the peak current sampling hold circuit of band compensation in described constant-current control circuit;
Sampling resistor, its first end connects the second end of described power switch, its second end ground connection;
Output capacitance, its first end connects the negative pole of described fly-wheel diode, its second end ground connection.
Compared with prior art, the utlity model has following advantage:
The peak current deviation generation circuit of the utility model embodiment can utilize the variable quantity of peak current in given interval to estimate that peak sampling hold circuit is due to the peak current deviation of sampling and causing in advance, and the peak current sampling hold circuit of band compensation can compensate by this peak current deviation the sampled value problem on the low side of the peak current that sampling causes in advance, improved sampling precision, thereby improved the control precision of utilizing peak value sampling to carry out output constant current control, improved the consistency of circuit.
Furthermore, the peak current deviation that estimation obtains both can be for having determined real peak current, also can regulate for the reference voltage to error amplifier, thereby making the error signal of error amplifier output can reflect real peak current, is also that error signal is enough accurate.
Accompanying drawing explanation
Fig. 1 is a kind of electrical block diagram that adopts the step down switching regulator of peak sampling hold circuit in prior art;
Fig. 2 is that the peak value sampling of Switching Power Supply shown in Fig. 1 keeps sequential chart;
Fig. 3 is the structural representation that the peak current deviation of the utility model embodiment produces circuit and peripheral circuit thereof;
Fig. 4 is that the deviation of peak current shown in Fig. 3 produces the middle sampling interval of circuit and the sequential schematic diagram of peak value sampling deviation;
Fig. 5 is the circuit structure diagram that the peak current deviation of the utility model embodiment produces the interval given time sampling hold circuit of circuit;
Fig. 6 is the wherein clock signal figure of a road sampling pulse of the interval given time sampling hold circuit shown in Fig. 5;
Fig. 7 is the peak current sampling hold circuit of band compensation of the utility model the first embodiment and the structural representation of peripheral circuit thereof;
Fig. 8 is the peak current sampling hold circuit of band compensation of the utility model the second embodiment and the structural representation of peripheral circuit thereof;
Fig. 9 is the structural representation of Switching Power Supply of the buck configuration of the utility model the first embodiment;
Figure 10 is the structural representation of the inverse-excitation type switch power-supply of the utility model the second embodiment.
Embodiment
Below in conjunction with specific embodiments and the drawings, the utility model is described in further detail, but should not limit protection range of the present utility model with this.
With reference to figure 3, the peak current deviation of the present embodiment produces circuit and comprises: interval given time sampling hold circuit 301 and estimation peak value sampling bias circuit 302.Wherein, interval given time sampling hold circuit 301 according to Preset Time interval to the peak current maintenance of sampling, the sampling time that shifts to an earlier date of the 303 pairs of peak currents in this Preset Time interval and peak sampling hold circuit becomes preset ratio, as a nonrestrictive example, this Preset Time is spaced apart kT
d, the in advance sampling time of peak sampling hold circuit 303 is T
d, be also that the proportionality coefficient between the two is k.The peak current that estimation peak value sampling bias circuit 302 obtains according to interval given time sampling hold circuit 301 calculates Preset Time interval kT
dinterior peak current deviation, and according to Preset Time interval kT
dinterior peak current deviation and preset ratio k estimate that this peak sampling hold circuit 303 is due to the peak current deviation of sampling and causing in advance.
With reference to figure 4, Fig. 4 shows peak current deviation and Preset Time interval (or being called the sampling interval) kT
drelation, at identical Preset Time interval kT
din, the variable quantity of sampled voltage (this sampled voltage flows through sampling resistor Rcs by electric current and obtains) is identical, is all k Δ V
cs.By detecting at KT
dthe variable quantity k Δ V of interior sampled voltage
cscan obtain sampling time T in advance
dinterior sampled voltage variable quantity is Δ V
cs.No matter the inductive current of circuit is in continuous state or on-off state, this relation exists all the time.
Fig. 5 shows the circuit structure of an interval given time sampling hold circuit in example, comprise: the first switch S 1, its first end receives sampled voltage (be specially in this example electric current and flow through the voltage Vcs that sampling resistor produces), and its control end receives the first sampling pulse T
s1; The first capacitor C 501, its first end connects the second end of the first switch S 1, its second end ground connection; The first voltage follower, its input connects the first end of the first capacitor C 501; Second switch S2, its first end receives sampled voltage (be specially in this example electric current and flow through the voltage Vcs that sampling resistor produces), and its control end receives the second sampling pulse T
s2, the second sampling pulse T
s2with the first sampling pulse T
s1between delay equal Preset Time interval kT
d; The second capacitor C 502, its first end connects the second end of second switch S2, its second end ground connection; Second voltage follower, its input connects the first end of the second capacitor C 502; The 3rd switch S 3, its first end connects the output of the first voltage follower, and its control end receives the inversion signal GTN that drives signal; The 4th switch, its first end connects the output of second voltage follower, and its control end receives the inversion signal GTN that drives signal; The 3rd capacitor C 503, its first end connects the second end of the 3rd switch S 3, its second end ground connection; The 4th capacitor C 504, its first end connects the second end of the 4th switch S 4, its second end ground connection.
As a nonrestrictive example, the first voltage follower comprises operational amplifier A mp1, and its positive input terminal is as the input of this first voltage follower, and its negative input end connects the output of self; Second voltage follower comprises operational amplifier A mp2, and its positive input terminal is as the input of this second voltage follower, and its negative input end connects the output of self.
Fig. 5 has comprised two-way sampling hold circuit, and Fig. 6 shows the wherein clock signal figure on a road, in conjunction with Fig. 5 and Fig. 6, T
s1be the first sampling pulse, as the first sampling pulse T
s1when high, the first switch S 1 conducting, sampled voltage Vcs enters in the first capacitor C 501, is made as the first sampling and keeps voltage Vcs1; As the first sampling pulse T
s1when low, the first switch S 1 is turn-offed, in the first capacitor C 501 first sampling keeps voltage Vcs1 to remain unchanged, operational amplifier A mp1 is as voltage follower, the 3rd switch S 3 is after driving finishes, conducting when the inversion signal GTN that drives signal is high, the sampling of first in the first capacitor C 501 keeps voltage Vcs1 to be delivered in the 3rd capacitor C 503, is that the 3rd sampling keeps voltage Vcs3; Similarly, can obtain equally the second sampling keeps voltage Vcs2 and the 4th sampling to keep voltage Vcs4.After obtaining the 3rd sampling maintenance voltage Vcs3 and the 4th sampling maintenance voltage Vcs4, these two voltages are subtracted each other, in the result that the peak value sampling that is then added in proportion keeps, just can obtain real peak current.
In conjunction with Fig. 2 and Fig. 6, real peak current is:
V
cspk=V
csa+△V
cs=V
csa+k△V
cs/k=V
csa+（V
cs4-V
cs3）/k
When the 3rd sampling keeps voltage Vcs3 to be zero, have:
V
cspk=V
csa+V
cs4/k
Being expressed as sampling interval set of time is to start in zero moment at inductive current, and the first, the 3rd sampling maintenance voltage is zero, and interval given time sampling hold circuit now only need to be used a road sampling hold circuit.
With reference to figure 7, the structural representation that it shows the first embodiment of the peak current sampling hold circuit 600 of being with compensation, comprising: peak sampling hold circuit 602, interval given time sampling hold circuit 603, estimation peak value sampling bias circuit 604, real peak counting circuit 601.
Peak sampling hold circuit 602 samplings keep the peak value of the sampled voltage Vcs on sampling resistor Rcs, obtain sampling and keep voltage Vcsa, due to sampled voltage Vcs, normally triangular wave and sampling pulse and driving pulse can not Complete Synchronizations, can cause sampling to keep voltage Vcsa and actual crest voltage Vcspk to have deviation, the shutoff marginal delay of supposing sampling pulse edge and driving pulse is spaced apart Δ Td, deviation voltage Δ Vcs.At interval k Δ Td, to sampled voltage Vcs, sampling keeps obtaining voltage Vcs3 and voltage Vcs4 to given time sampling hold circuit 603.Estimation peak value sampling bias circuit 604, for keeping the voltage obtaining to obtain peak value sampling deviation according to sampling in Preset Time interval, also calculates (V
cs4-V
cs3the numerical value of)/K.Real peak counting circuit 601 can be for superposition, by peak value sampling deviation (V
cs4-V
cs3the peak value sampling value that)/K and peak sampling hold circuit 602 obtain calculates real peak Vcspk.Output equivalent current calculation unit calculates according to this real peak Vcspk the equivalent voltage that output equivalent electric current output represent this output equivalent electric current, and this equivalence voltage transmission is carried out to error amplification to error amplifier EA and reference voltage V ref1.
The peak current sampling hold circuit 600 compensating due to band is generally used for loop constant current control, general process output equivalent Current calculation circuit and reference voltage V ref1 carry out error amplification, characteristic from error amplifier, an input tunes up and is equivalent to another input reduction, and the regulating action of two inputs is identical.Therefore, can adopt the structure of the second embodiment shown in Fig. 8.
In the second embodiment shown in Fig. 8, the peak current sampling hold circuit 700 of band compensation comprises peak sampling hold circuit 602, interval given time sampling hold circuit 603, estimation peak value sampling bias circuit 604, reference voltage regulating circuit 701.Wherein, peak sampling hold circuit 602 samplings keep the peak value sampling value obtaining directly to transfer to output equivalent Current calculation circuit.The amount of deflection that estimation peak value sampling bias circuit 604 obtains is directly used for the reference voltage V ref1 of regulating error amplifier EA, reference voltage V ref2 after adjusted, error amplifier EA carries out error amplification by the equivalent voltage of the reference voltage V ref2 after this adjusting and the output of output equivalent Current calculation circuit, identical with the stack of the real peak counting circuit 601 shown in Fig. 7 in effect.
Fig. 9 shows the circuit structure of the Switching Power Supply of the utility model the first embodiment, comprise constant-current control circuit 800 and with the main circuit of its coupling, in this embodiment, main circuit is buck configuration.
Furthermore, this constant-current control circuit 800 comprises: the peak sampling hold circuit 805 of error amplifier 801, pwm signal generation circuit 802, logic and driver circuitry 803, output equivalent Current calculation circuit 804, band compensation.Wherein, the structure of the peak sampling hold circuit 805 of band compensation can be with reference to the peak sampling hold circuit 600 of the band compensation shown in Fig. 7.In other words, the embodiment shown in Fig. 8 has replaced to the peak sampling hold circuit in traditional structure the peak sampling hold circuit 805 of band compensation.
Wherein, output equivalent Current calculation circuit 804 is connected with the peak sampling hold circuit 805 of band compensation, the real peak current producing according to the peak sampling hold circuit 805 of band compensation calculates output equivalent electric current, and output represents the equivalent voltage of this output equivalent electric current; The first input end of error amplifier 801 receives the equivalent voltage that output equivalent Current calculation circuit 804 produces, and its second termination is received reference voltage V ref1, and its output produces error signal; Pwm signal generation circuit 802 receives the error signal of error amplifier 801 outputs, and produces pwm signal GT1 according to this error signal; Logic and driver circuitry 803 receives the pwm signal GT1 of pwm signal generation circuit 802 outputs, and produces and drive signal GT according to this pwm signal GT1, and this drives signal GT for the turn-on and turn-off of driving power switch M1.
In embodiment shown in Fig. 9, main circuit comprises: sustained diode 1, and its negative pole connects Input voltage terminal Vin; Power switch M1, its first end connects the positive pole of sustained diode 1, and its control end receives the driving signal that constant-current control circuit 800 produces, and its second end is connected with the input of the peak current sampling hold circuit 805 of band compensation in constant-current control circuit 800; Sampling resistor Rcs, its first end connects the second end of power switch M1, its second end ground connection; Inductance L 1, its first end connects the positive pole of sustained diode 1; Output capacitance C1, its first end connects the negative pole of sustained diode 1, and its second end connects the second end of inductance L 1.
Wherein, power switch M1 can be for example power MOS transistor, or other various suitable device for power switching.
In power switch M1 conduction period, the electric current that flows through inductance L 1 raises, and the peak current sampling hold circuit 805 of band compensation is by the peak current in sampling resistor Rcs sampling inductance L 1.The equivalent voltage that is calculated output equivalent electric current this output equivalent electric current of output expression by output equivalent Current calculation circuit 804, this equivalent voltage and reference voltage V ref1 carry out error amplification.Output current Iout can be expressed as following form:
Iout=k1*Vref1/Rcs
Wherein k1 is proportionality coefficient, and Vref1 is in the voltage of reference voltage V ref1, and Rcs is the resistance value of sampling resistor Rcs.
The output of error amplifier 801 can connect compensating network, and the error voltage of error amplifier 801 outputs is controlled pwm signal generation circuit 802, obtains pwm signal GT1, then through logic and driver circuitry 803, obtains the driving signal GT of driving power pipe M1.Inductance L 1, as energy-storage travelling wave tube, when power switch M1 carries out switch motion, is stored and releases energy.Sampling resistor Rcs sample streams, through the electric current of inductance L 1, obtains inductive current sampled voltage Vcs1.
Figure 10 shows the circuit structure of the Switching Power Supply of the utility model the second embodiment, comprise constant-current control circuit 900 and with the main circuit of its coupling, in this embodiment, main circuit is inverse-excitation type structure.
Furthermore, this constant-current control circuit 900 comprises: the peak sampling hold circuit 905 of error amplifier 901, pwm signal generation circuit 902, logic and driver circuitry 903, output equivalent Current calculation circuit 904, band compensation.Wherein, the structure of the peak sampling hold circuit 905 of band compensation can be with reference to the peak sampling hold circuit 600 of the band compensation shown in Fig. 7.
Wherein, output equivalent Current calculation circuit 904 is connected with the peak sampling hold circuit 905 of band compensation, the real peak current producing according to the peak sampling hold circuit 905 of band compensation calculates output equivalent electric current, and output represents the equivalent voltage of this output equivalent electric current; The first input end of error amplifier 901 receives the equivalent voltage that output equivalent Current calculation circuit 904 produces, and its second termination is received reference voltage V ref1, and its output produces error signal; Pwm signal generation circuit 902 receives the error signal of error amplifier 901 outputs, and produces pwm signal GT1 according to this error signal; Logic and driver circuitry 903 receives the pwm signal GT1 of pwm signal generation circuit 902 outputs, and produces and drive signal GT according to this pwm signal GT1, and this drives signal GT for the turn-on and turn-off of driving power switch M1.
In embodiment shown in Figure 10, main circuit comprises: transformer T1, and the Same Name of Ends of its former limit winding L 2 receives input voltage vin; Sustained diode 2, the different name end of the secondary winding L 3 of its anodal connection transformer T1, the Same Name of Ends ground connection of secondary winding L 3; Power switch M1, the different name end of the former limit winding L 2 of its first end connection transformer T1, its control end receives the driving signal GT that constant-current control circuit 900 produces, and its second end is connected with the input of the peak current sampling hold circuit 905 of band compensation in constant-current control circuit 900; Sampling resistor Rcs, its first end connects the second end of power switch M1, its second end ground connection; Output capacitance Cbulk, its first end connects the negative pole of sustained diode 2, its second end ground connection.
Constant-current control circuit 900 in Switching Power Supply shown in Figure 10 is similar with structure, the operation principle of the constant-current control circuit 800 shown in Fig. 9, repeats no more here.
It should be noted that in the Switching Power Supply shown in Fig. 9 and Figure 10, the peak sampling hold circuit of the band compensation that constant-current control circuit 800 and constant-current control circuit 900 adopt is the structure shown in Fig. 7, it will be appreciated by those skilled in the art that this constant-current control circuit also can adopt the peak sampling hold circuit of the band compensation shown in Fig. 8.
To sum up, the utility model discloses a kind of constant-current control circuit and Switching Power Supply with peak current compensation, in utilization sampling given interval, the variable quantity of peak current compensates the sampled value problem on the low side of the peak current causing due to sampling delay, be conducive to improve sampling precision, thereby improve constant-current control accuracy.Circuit of the present utility model is realized simple, can obviously improve the consistency of circuit, and describe embodiment of the present utility model and effect with reference to the accompanying drawings.
What should be understood that is that above-described embodiment is just to explanation of the present utility model; rather than to restriction of the present utility model; any utility model not exceeding within the scope of the utility model connotation is created; include but not limited to change, the replacement to the type of components and parts or model to local structure; and the replacement of other unsubstantialities or modification, within all falling into the utility model protection range.
Claims (11)
1. peak current deviation produces a circuit, it is characterized in that, comprising:
Interval given time sampling hold circuit, keeps peak current according to Preset Time interval sampling, and this Preset Time interval becomes preset ratio with peak sampling hold circuit to the sampling time that shifts to an earlier date of described peak current;
Estimation peak value sampling bias circuit, the peak current obtaining according to described interval given time sampling hold circuit calculates the peak current deviation in described Preset Time interval, and estimates that according to the peak current deviation in described Preset Time interval and described preset ratio this peak sampling hold circuit is due to the peak current deviation of sampling and causing in advance.
2. peak current deviation according to claim 1 produces circuit, it is characterized in that, described interval given time sampling hold circuit comprises:
The first switch, its first end receives sampled voltage, and its control end receives the first sampling pulse;
The first electric capacity, its first end connects the second end of described the first switch, its second end ground connection;
The first voltage follower, its input connects the first end of described the first electric capacity;
Second switch, its first end receives sampled voltage, and its control end receives the second sampling pulse, and the delay between described the second sampling pulse and described the first sampling pulse equals described Preset Time interval;
The second electric capacity, its first end connects the second end of described second switch, its second end ground connection;
Second voltage follower, its input connects the first end of described the second electric capacity;
The 3rd switch, its first end connects the output of described the first voltage follower, and its control end receives the inversion signal that drives signal;
The 4th switch, its first end connects the output of described second voltage follower, and its control end receives the inversion signal of described driving signal;
The 3rd electric capacity, its first end connects the second end of described the 3rd switch, its second end ground connection;
The 4th electric capacity, its first end connects the second end of described the 4th switch, its second end ground connection.
3. with a peak current sampling hold circuit for compensation, it is characterized in that, comprising:
Peak sampling hold circuit described in claim 1 or 2 and peak current deviation produce circuit;
Real peak counting circuit, the peak current that the peak current deviation of using described peak current deviation generation circuit to obtain obtains described peak sampling hold circuit compensates, and determines real peak current.
4. a constant-current control circuit, is characterized in that, comprising:
The peak current sampling hold circuit of band compensation claimed in claim 3;
Output equivalent Current calculation circuit, is connected with described real peak counting circuit, calculates the equivalent voltage of output equivalent electric current this output equivalent electric current of output expression according to described real peak current;
Error amplifier, its first input end receives the equivalent voltage that described output equivalent Current calculation circuit produces, and its second termination is received reference voltage, and its output produces error signal;
Pwm signal generation circuit, receives the error signal of described error amplifier output, and produces pwm signal according to this error signal;
Logic and driver circuitry, receives the pwm signal of described pwm signal generation circuit output, and produces and drive signal according to this pwm signal, and described driving signal is for the turn-on and turn-off of driving power switch.
5. with a peak current sampling hold circuit for compensation, it is characterized in that, comprising:
Peak sampling hold circuit described in claim 1 or 2 and peak current deviation produce circuit;
Reference voltage regulating circuit, produces according to described peak current deviation the peak current deviation that circuit obtains default reference voltage is regulated, the reference voltage after adjusted.
6. a constant-current control circuit, is characterized in that, comprising:
The peak current sampling hold circuit of band compensation claimed in claim 5;
Output equivalent Current calculation circuit, peak sampling hold circuit in the peak current sampling hold circuit compensating with described band is connected, and the peak current obtaining according to described peak sampling hold circuit calculates the equivalent voltage of output equivalent electric current this output equivalent electric current of output expression;
Error amplifier, its first input end receives the equivalent voltage that described output equivalent Current calculation circuit produces, its second termination is received the reference voltage after the adjusting that the reference voltage regulating circuit in the peak current sampling hold circuit of described band compensation produces, and its output produces error signal;
Pwm signal generation circuit, receives the error signal of described error amplifier output, and produces pwm signal according to this error signal;
Logic and driver circuitry, receives the pwm signal of described pwm signal generation circuit output, and produces and drive signal according to this pwm signal, and described driving signal is for the turn-on and turn-off of driving power switch.
7. a Switching Power Supply, is characterized in that, comprising:
Constant-current control circuit described in claim 4 or 6;
Main circuit with described constant-current control circuit coupling.
8. Switching Power Supply according to claim 7, is characterized in that, described main circuit is buck configuration.
9. Switching Power Supply according to claim 8, is characterized in that, this main circuit comprises:
Fly-wheel diode, its negative pole connects Input voltage terminal;
Power switch, its first end connects the positive pole of described fly-wheel diode, and its control end receives the driving signal that described constant-current control circuit produces, and its second end is connected with the input of the peak current sampling hold circuit of band compensation in described constant-current control circuit;
Sampling resistor, its first end connects the second end of described power switch, its second end ground connection;
Inductance, its first end connects the positive pole of described fly-wheel diode;
Output capacitance, its first end connects the negative pole of described fly-wheel diode, and its second end connects the second end of described inductance.
10. Switching Power Supply according to claim 7, is characterized in that, described main circuit is inverse-excitation type structure.
11. Switching Power Supplies according to claim 10, is characterized in that, this main circuit comprises:
Transformer, the Same Name of Ends of its former limit winding receives input voltage;
Fly-wheel diode, its anodal different name end that connects the secondary winding of described transformer, the Same Name of Ends ground connection of described secondary winding;
Power switch, its first end connects the different name end of the former limit winding of described transformer, its control end receives the driving signal that described constant-current control circuit produces, and its second end is connected with the input of the peak current sampling hold circuit of band compensation in described constant-current control circuit;
Sampling resistor, its first end connects the second end of described power switch, its second end ground connection;
Output capacitance, its first end connects the negative pole of described fly-wheel diode, its second end ground connection.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320466246.9U CN203445774U (en) | 2013-07-31 | 2013-07-31 | Peak value current deviation generation circuit, peak value current sample hold circuit with compensation, constant current control circuit and switch power source |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320466246.9U CN203445774U (en) | 2013-07-31 | 2013-07-31 | Peak value current deviation generation circuit, peak value current sample hold circuit with compensation, constant current control circuit and switch power source |
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| CN203445774U true CN203445774U (en) | 2014-02-19 |
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| CN201320466246.9U Expired - Fee Related CN203445774U (en) | 2013-07-31 | 2013-07-31 | Peak value current deviation generation circuit, peak value current sample hold circuit with compensation, constant current control circuit and switch power source |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103354417A (en) * | 2013-07-31 | 2013-10-16 | 杭州士兰微电子股份有限公司 | Constant-current control circuit with peak current compensation and switching power supply |
| CN105006973A (en) * | 2015-07-17 | 2015-10-28 | 东南大学 | Constant current control system for output current of primary-side feedback flyback power supply converter |
| CN106645879A (en) * | 2017-01-18 | 2017-05-10 | 深圳市思远半导体有限公司 | Device and method for inductive current sampling and holding of switching power supply circuit |
| CN107204706A (en) * | 2016-03-16 | 2017-09-26 | 精工半导体有限公司 | Switching regulaor |
| CN108390560A (en) * | 2018-05-08 | 2018-08-10 | 杰华特微电子（杭州）有限公司 | The control circuit and control method of reduction voltage circuit |
| CN113747629A (en) * | 2021-10-15 | 2021-12-03 | 美芯晟科技（北京）有限公司 | Dimming control circuit and dimming chip thereof |
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- 2013-07-31 CN CN201320466246.9U patent/CN203445774U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103354417A (en) * | 2013-07-31 | 2013-10-16 | 杭州士兰微电子股份有限公司 | Constant-current control circuit with peak current compensation and switching power supply |
| CN105006973A (en) * | 2015-07-17 | 2015-10-28 | 东南大学 | Constant current control system for output current of primary-side feedback flyback power supply converter |
| CN105006973B (en) * | 2015-07-17 | 2017-10-31 | 东南大学 | A kind of Constant Current Control System of primary side feedback flyback power supply converter output current |
| CN107204706A (en) * | 2016-03-16 | 2017-09-26 | 精工半导体有限公司 | Switching regulaor |
| CN106645879A (en) * | 2017-01-18 | 2017-05-10 | 深圳市思远半导体有限公司 | Device and method for inductive current sampling and holding of switching power supply circuit |
| CN106645879B (en) * | 2017-01-18 | 2019-04-05 | 深圳市思远半导体有限公司 | A kind of the inductive current sampling holding meanss and method of switching power circuit |
| CN108390560A (en) * | 2018-05-08 | 2018-08-10 | 杰华特微电子（杭州）有限公司 | The control circuit and control method of reduction voltage circuit |
| CN108390560B (en) * | 2018-05-08 | 2024-04-19 | 杰华特微电子股份有限公司 | Control circuit and control method of step-down circuit |
| CN113747629A (en) * | 2021-10-15 | 2021-12-03 | 美芯晟科技（北京）有限公司 | Dimming control circuit and dimming chip thereof |
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