CN1761135A - Current replication to avoid leb restriction of dc-dc boost converter - Google Patents
Current replication to avoid leb restriction of dc-dc boost converter Download PDFInfo
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- CN1761135A CN1761135A CN 200510079485 CN200510079485A CN1761135A CN 1761135 A CN1761135 A CN 1761135A CN 200510079485 CN200510079485 CN 200510079485 CN 200510079485 A CN200510079485 A CN 200510079485A CN 1761135 A CN1761135 A CN 1761135A
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Abstract
A current replication circuit that avoids the LEB period restriction of a DC-DC boost converter. The DC-DC boost converter regulates an output voltage by switching an input voltage through an inductor and a diode using a switch controller employing current feedback control and providing a PWM signal to control a switch coupled to the inductor. The current replication circuit includes a current sensor, a ramp generator, and a summing device. The current sensor samples current through the inductor while the switch is off and provides a sample voltage indicative of inductor current just before the switch is turned on. The ramp generator provides a ramp voltage replicating current increase of the inductor while the switch is on. The summing device adds the sample voltage to the ramp voltage to develop a replication voltage used for feedback current control by the switch controller.
Description
The mutual reference of related application
The present invention requires to apply for the priority of No. the 0413494.6th, the UK Patent Application case on June 16th, 2004, and the integral body of this case is disclosed in this and is incorporated herein by reference.
Technical field
Invention about the direct current that adopts current feedback to direct current transducer, and especially in regard to a current replication circuit, it enable to eliminate a direct current to lead-edge-blanking (LEB) cycle of DC boost converter to eliminate the duty cycle restriction.
Background technology
Traditional direct current switches the electric current of flow through inductor and diode to DC boost converter, becomes a bigger and adjusted output voltage to change an input voltage.This switching is implemented by an electronic switch typically, and such as metal-oxide semiconductor (MOS), field-effect transistor (MOSFET), the grid that this field-effect transistor has it is subjected to the control of a pulse-width modulation (PWM) control signal.The drain electrode of this MOS field-effect transistor and source path are connected in this inductor/diode junction and are referenced between the sense resistor such as the common node of ground connection.An on-off controller monitors this output voltage by a voltage feedback signal, and the voltage by this sense resistor monitors this inductor current, and know usually and use this information and other information to produce this pulse-width modulation control signal known to the knowledgeable as having in this technical field.
When operation, this on-off controller makes this switch closed circuit (for example, make this mos field effect transistor conducting), starting first stage of each pulse width modulation cycle, and place input voltage effectively on this inductor and sense resistor.Represent rising along with the time is linear of inductor current, and this sensing voltage is monitored by this on-off controller during the first of each pulse width modulation cycle across the voltage of this sense resistor.This feedback current sensing signal and a reference value are made comparisons, and judge when be the next one shutoff opening time of this electronic switch with at least a portion, to start the second stage of each pulse width modulation cycle.When this switch is disconnected (or open circuit), this diode of inductor current forward bias of enhancing, and flow among the output capacitor, to produce this output voltage.Operation repeats to implement for each pulse width modulation cycle in this way.This transducer is called " boosting " transducer, because this VD is greater than this DC input voitage.Traditional direct current is forward position damped oscillation to the special problem that DC boost converter had, and it results from this inductor current when this switch conduction (or closed circuit).The stray capacitance joint line inductance of this switch and this sense resistor collective form a storehouse circuit, and it causes this sensing voltage vibration (for example, damping pure oscillation) when this switch conduction.This on-off controller adopts a lead-edge-blanking, and (Leading Edge Blanking, LEB) cycle, in the cycle, it ignored the initial damped oscillation of present sensing voltage in this lead-edge-blanking.Particularly, T
LEBPeriodic system is used in ignores initial damped oscillation, to prevent beginning to locate too early termination at each pulse width modulation cycle.Yet, this T
LEBThe minimum work period of this boost converter of cycle limit, and thereby limit the output voltage range of a given input voltage.For example, when the possible weak result who avoids using a damped oscillation signal when being used for FEEDBACK CONTROL, use T
LEBCycle prevents to use the lower work period, makes this output voltage not be allowed near this input voltage.
In the past on the experience, this problem by a direct current to direct current transducer and both combination of adjuster and solved.So solution is inefficient in essence for the quantity of power consumption and required element.We provide a kind of efficient direct current to DC boost converter at expectation, and it avoids adjusting according to an oscillator signal, and it is to enable this output voltage quite near this input voltage level.
Summary of the invention
A kind of current replication circuit according to an embodiment of the invention is avoided the lead-edge-blanking cycle limit of a direct current to DC boost converter.This direct current by using an on-off controller that adopts Current Feedback Control and switch through the input voltage of an inductor and a diode and provide a pulse-width modulation (PWM) signal with the switch of control connection to this inductor, and is adjusted output voltage to DC boost converter.This current replication circuit comprises a current sensor, a ramp generator, and a summation device.The electric current of this current sensor sampling this inductor of process when this switch is shutoff, and the indication sampling voltage of the inductor current before this open relation conducting just is provided.This ramp generator provides a ramp voltage that duplicates the electric current increase of this inductor when this switch conduction.This summation device is added to this ramp voltage with this sampling voltage, to produce the voltage that duplicates of a feedback current control that is used in this on-off controller.
In this way, but not the demonstration stray inductance of this inductor of sensing process and the real electric current of the damped oscillation that electric capacity caused, the electric current of this inductor of process is replicated, and this electric current that duplicated is used in Current Feedback Control.During first phase place of each pulse width modulation cycle, this input voltage is applied to this inductor, cause electric current enhancing in this inductor, and first phase place of each pulse width modulation cycle can more early be terminated, and allows the work period that work period of the previous permission that a ratio caused because of the lead-edge-blanking cycle limit significantly reduces by this.Then, this output voltage can be controlled so as to one quite near the level of this input voltage.
Several variations and embodiment can be contemplated to.This current sensor can be sampling and holding device, the electric current of its this inductor of sampling process before switching, and after switching, keep this sampling voltage.In an embodiment, a current mirror is connected to this diode, so that the image electric current of an indication through the electric current of this diode to be provided.Under a situation, this sampling and holding device are connected to this current mirror, with a sampling keeping this image electric current as this sampling voltage.This on-off controller can provide a preliminary pulse-width signal to a buffer that this pulse-width signal is provided.This buffer postpones this pulse-width signal with respect to the preliminary thing relatively of this pulse-width signal haply.This preliminary pulse-width signal is provided,, makes this sampling voltage before switching, be obtained to control this sampling and holding device.This ramp generator can be constructed as the input voltage of cutting apart according to by the inductance value of this inductor, and the enhancing of synthetic this inductor current.A gain square can be provided, be multiplied by a zoom factor this is duplicated voltage, with simulation or duplicate this voltage sense signal, it is before to produce on a sense resistor that is connected to this switch, and thereby measures real inductor current.
A kind of direct current according to an embodiment of the invention comprises direct current transducer: an inductor, and it has one and receives first end with respect to the input voltage of a common node; A diode, it has an anode that is connected to second end of this inductor; A capacitor, it is connected in the negative electrode of this diode and produces between the common node of an output voltage; A switching device, it has second end that is connected in this inductor and the controlled current flow path between this common node and one and is used in the control input end that enables or forbid this current path; An on-off controller, it has an input that receives a current sensing signal and one provides the output of a pulse-width modulation control signal to the control input end of this switching device; A ramp generator, it provides a ramp signal, the slope that this ramp signal cording has the electric current of a simulation this inductor of process when this switching device conducting to increase; A current sensor, it provides a current sampling signal, its indication when this switching device turn-off and just before this switching device conducting through the current level of this diode; And a summation device, it adds this oblique wave and current sampling signal together, with the reproducing signals that provides to be used in this current sensing signal.
Several variations and embodiment can be contemplated to.This switching device can be the electronic switching device of a mos field effect transistor (MOSFET) or any other suitable form.This current sensor can be a sampling and holding circuit, and its sampling current and its keep the current sampling signal of a sampling voltage as the sampled overcurrent of indication.A current mirror can be connected to this diode, so that an image electric current to be provided, and this current sensor can be a sampling and holding circuit, and it is connected to this current mirror, to take a sample this image electric current and keep the current sampling signal of the electric current that a sampling voltage took a sample as indication.This on-off controller can comprise a buffer, and this buffer has the input and the output that this pulse-width modulation control signal is provided that receive a preliminary pulse-width signal.This preliminary pulse-width signal is provided to this sampling and holding circuit, and this sampling and holding circuit keep this current sampling signal according to this preliminary pulse-width signal.A gain square can be set up, this reproducing signals is multiplied by a zoom factor, to produce this current sensing signal.
A kind of elimination direct current according to an embodiment of the invention makes the voltage of the previous permission that pulse-width modulation work period of minimizing and ratio caused because of the lead-edge-blanking cycle limit become possibility near a lot of output voltage of this input voltage to the method for the lead-edge-blanking cycle limit of DC boost converter.This method comprise judgement when this switch be open circuit and just before this switch is closed circuit the time this inductor current level and the current level signal of a correspondence is provided; The electric current that synthesizes this inductor when this switch is closed circuit increases and provides the ramp signal of a correspondence; And this current level and ramp signal added together, to produce a current feedback sensing signal that offers this sampling controller.
This method can comprise preliminary pulse-width signal of generation and this preliminary pulse-width signal of buffering, so that this pulse-width modulation control signal to be provided.This method can comprise according to this preliminary pulse-width signal sampling current and keep a current sampling.This sampling and keep can comprise the electric current that conversion took a sample becomes a voltage sampling.The buffering of this preliminary pulse-width signal can comprise and postpone this pulse-width modulation control signal, to guarantee sampling before switching.The inductance value that this method can comprise according to this input voltage and this inductor produces this ramp signal.
Description of drawings
With reference to execution mode and back accompanying drawing formula, interests of the present invention, characteristic and advantage will become and be easier to understand, wherein:
The 1st figure is the schematic diagram of a traditional direct current to a simplification of DC boost converter;
The 2nd figure is the curve chart of the ideal current waveform in the inductor of the 1st figure, and it comprises the continuous wave in this current sensing element and this diode when this switch open circuit;
3A and 3B figure are curve charts, be illustrated in since stray inductance and damped oscillation that electric capacity caused in conjunction with during each stage of the pulse width modulation cycle of effect through the expression of actual (for example, true) of the electric current of the inductor of the 1st figure;
The 4th figure is the T that overcomes that implements according to one embodiment of present invention
LEBA direct current of cycle limit is to a rough schematic view of DC boost converter;
5A figure is the curve chart of this ramp generator, the enhancing of the electric current in the inductor of expression the 4th figure when this switch conduction;
5B figure is to be the curve chart of the electric current that turn-offs and measure in the inductor of the 4th figure and the diode just before this switch conduction the time or take a sample out when this switch;
5C figure is this ramp voltage and an inductor current of this sampling of 5B figure and selectively be multiplied by the totalling of the switch path current information that a zoom factor simulates and the curve chart of sensing voltage by adding up 5A figure; And
The 6th figure is more detailed signal and calcspar, illustrate in greater detail according to the sampling current of this diode of process of an one exemplary embodiment of the present invention and with the direct current of the 4th figure the relevant sequential of maintenance to the sample of the electric current of measuring of DC boost converter.
400 direct currents are to DC boost converter
401 current sensing devices
403 ramp generators
405 summation devices
407 multipliers or gain square
The TLEB diode current
The VSH sensing voltage
The VR ramp voltage
VREP duplicates voltage signal
VS ' current feedback sensing signal
The COM common node
The VIN input voltage
The L inductor
S1 mos field effect transistor switch
The D1 diode
The R1 resistor
The R2 resistor
The VOUT output voltage
The C1 capacitor
I (D1) electric current
100 direct currents are to DC boost converter
101 on-off controllers
The RS sense resistor
I (RS) electric current
The VS sensing voltage
The VFB output voltage feedback signal
301 damped oscillations
303 damped oscillations
601 current mirrors
The 603D D-flip flop
605 buffer devices
Embodiment
Propose following narration, know that usually the knowledgeable can implement and use the interior the present invention of environment who is arranged at an application-specific and condition thereof so that have in this technical field.Yet many variations of this preferred embodiment for obvious, and can be applied to other embodiment in this defined overall principle for haveing the knack of this operator.Therefore, the present invention is not intended to be subject to illustrated in this and the specific embodiment of narration, and meet with in principle and novel characteristic the widest consistent scope that this disclosed.The 1st figure is the rough schematic view of a traditional direct current to DC boost converter 100.With respect to a common node COM (for example, ground connection or " power ground ") measured input voltage VIN is applied to an end of an inductance L, and the other end of this inductor is connected to the drain electrode of a mos field effect transistor switch S 1 and is connected to the anode of diode D1.This switch S 1 is shown as a mos field effect transistor, though the electronic switch of other suitable forms can also be contemplated to.Generally speaking, this switch S 1 comprises a control input end (for example, grid) and a current path (for example, draining to source electrode), and this current path is subjected to the control of this control input.Any type of device of implementing a controlled one pole double-throw (SPST) function is envisioned.The source electrode of this switch S 1 is connected to the end of a sense resistor RS, and the other end of this sense resistor RS is connected to COM.Electric current through this current-sense resistor RS is shown as I (RS).This current-sense resistor RS produces a sensing voltage VS in the place, source of this switch S 1, and wherein, VS is provided to an on-off controller 101.This on-off controller 101 provides a pulse-width modulation (PWM) to control signal to the grid of this switch S 1.The negative electrode of this diode D1 is connected to an end of a resistor R 2, and the negative electrode of this diode D1 is connected to the end of a capacitor C1 in the output node place of a generation output voltage VO UT.The electric current of this diode D1 of flowing through is shown as I (D1).The other end of this capacitor C1 is connected to COM, and the other end of this resistor R 2 is connected to an end of a resistor R 1, and the other end of this resistor R 1 is connected to COM.The resistor R 1 of series connection and the contact between the R2 produce an output voltage feedback signal VFB, and this output voltage feedback signal VFB feeds back to this on-off controller 101.For this boost converter 100, this output voltage VO UT is greater than this input voltage VIN.
The 2nd figure is that the ideal current waveform of the inductor L of this boost converter 100 (is shown I
INDUCTOR) figure, it comprises the continuous wave (that is, I (RS)) of this current-sense resistor RS when switch S 1 conducting (or closed circuit) and the continuous wave (that is, I (D1)) of this diode D1 when switch S 1 is turn-offed (or open circuit).The following integer value that is designated as of those current values, the pulse width modulation cycle number that its representative is continuous.Particularly, first pulse width modulation cycle " n " starts from time t1, one of its Initiation by time t1 to time t2 by an ideal current I (RS)
nThe shown phase I, thereafter then one by time t2 to time t3 by an ideal current I (D1)
nThe second stage of shown pulse width modulation cycle n.Next pulse width modulation cycle " n+1 " starts from time t3, and it is shown as an ideal current I (RS)
N+1Or the like.In traditional operation, this on-off controller 101 monitors this VFB and VS signal, to trigger this pulse-width signal conducting or to turn-off this switch S 1, become a predetermined voltage level to adjust VOUT, or adjust this inductor current between minimum value and maximum (for example being respectively I1 and I2).Though do not show, this on-off controller 101 is included as has feedback sense and control circuit or the logical circuit of knowing usually known to the knowledgeable in this technical field, such as comprising multiple mutual conductance (transconductance) (gm) level and/or summation amplifier, an electric current slope compensation (for example, triangular wave or sawtooth waveforms or analog) generator, or the like, to produce this pulse-width signal, be used to adjust the loop of VOUT with control.
When in fact this switch S 1 connects its drain electrode and source electrode together the time in time t1 conducting, in fact this input voltage VIN is placed on the resistor R S of this inductor L and this quite little value.During the phase I of this pulse width modulation cycle, the ideal current of this inductor L that flows through increases paramount value I2 linearly by low value I1, as is shown I (RS)
nDuring when this switch S 1 shutoff thereby in fact with this inductor L and this resistor R S disconnection, the energy of institute's construction causes this ideal current I (D1) in this inductor L
nThis diode D1 that flows through with to this output capacitor C1 charging, and produces this output voltage VO UT.In time t2, this electric current I (D1)
nReduce I1 when being formed in time t3 linearly by I2, when t3, this switch S 1 conducting once more is with the next pulse width modulation cycle n+1 of Initiation.
3A and 3B figure are curve charts, and (for example, in fact) is illustrated in and shows because the electric current of this inductor L that flows through during each stage of the pulse width modulation cycle of the damped oscillation effect of the combination of stray inductance and electric capacity for more realistically.3A figure is representative I (RS)
nTime t1 and voltage VS (or the VS between the t2
n) curve chart.Show that respectively low high-voltage level V1 of reaching and V2 are for representing low and high current level I1 and I2.This mos field effect transistor switch S 1 is in conjunction with a no small stray electrical capacity, the stray inductance of itself and this circuit (for example, conductive traces, the wafer pin connects or the like) and resistance is (for example, RS and other dead resistances) combination, and collectively form a vibration storehouse circuit.When S1 in time T 1 conducting during with this n pulse width modulation cycle of Initiation, forward position damped oscillation (for example, damped oscillation sinusoidal waveform) after time t1 in this VS
nProduce on the signal, it is shown as 301.It should be noted that for example, this damped oscillation has an initial high peak 302, it may surpass V2 (it represents I2), if it directly is used as this feedback signal, then it may cause the early stopping excessively of the phase I of this pulse width modulation cycle.The direct current that adopts current feedback and comprise this boost converter 100 typically adopts a lead-edge-blanking cycle or T to direct current transducer
LEB, it prevents that the effect of so damped oscillation from disturbing the operation of this feedback loop.This T
LEBCycle is set arbitrarily during enough with one, to ignore so damped oscillation, till it disappears, and thereby prevent each pulse width modulation cycle begin to locate cross early stopping.
Be used in the T that crosses early stopping of the phase I that prevents pulse width modulation cycle
LEBThe minimum work period of this boost converter 100 of cycle limit, and thereby the output voltage range of restriction for a given input voltage.For this boost converter 100, for example, use this T
LEBCycle does not allow to implement the very short work period, makes to force this output voltage VO UT for big more a lot of than VIN.This on-off controller 101 comprises an internal comparator or analog (not shown), and it is this VS voltage and a reference value relatively, when has arrived predetermined high (or maximum) level to judge this inductor current.In many configurations, we expect to reduce poor to time t2 by time t1, or t2-t1, early take place to cause time t2, reduce the work period of this pulse-width modulation control signal by this.Then, the minimizing in the pulse-width modulation work period makes the minimizing of the level of this output voltage VO UT become possibility, makes it than the level near VIN.Yet, be used in the T of the damped oscillation 301 of avoiding this VS signal
LEBCycle forces to apply an artificial minimum value restriction for the work period of this pulse-width modulation.At this T
LEBDuring end cycle, this VS voltage is greater than this desired destination level, and forces VOUT big more a lot of than VIN with manual type.
According to historical experience, this problem by a direct current to direct current transducer and both combination of adjuster and solve.So solution is inefficient in essence for the quantity of power consumption and required element.
3B figure is that diode current I (D1) is in time t2 and t3 (or I (D1)
n) between curve chart.In shown in configuration in, the damped oscillation 303 of this I (D1) electric current that begins during in time t2 when this switch S 1 is turn-offed is more no problem, because be not monitored because of the purpose of control, and thereby is left in the basket for the purposes of the present invention.Yet, it should be noted this electric current I (D1)
nWhen the second stage of this pulse width modulation cycle finishes and (was shown 305) just before time t3 is quite stable.
The 4th figure is one and overcomes this T
LEBThe direct current that an one exemplary embodiment according to the present invention of cycle limit is implemented is to the rough schematic view of DC boost converter 400.This boost converter 400 has with this boost converter 100 similarly organizes structure, and wherein, similar elements shows with identical reference symbol.Sense resistor RS is not removed because do not need, and makes the source electrode of this switch S 1 be connected directly to COM.A current sensing device 401 is connected in this current path between this inductor L and this diode D1, to be used for this diode current of sensing worker (D1) and to be used to produce the sensing voltage VSH of a correspondence.In shown in specific embodiment in, this current sensing device 401 is a sampling and holding device, it is in following sampling this electric current I (D1) of a scheduled time, and the voltage VSH of sampling of correspondence of the snapshot of expression I (D1) is provided.In an embodiment, this current sensing device 401 this electric current I (D1) of taking a sample constantly, and remain on just in time when approximately this I (D1) electric current has dropped to than low level I1 and just in time conducting is with the next pulse width modulation cycle of Initiation (for example once more in this switch S 1, in time t1, t3 or the like) time value of taking a sample.Therefore, this electric current is sampled in the final end of each pulse width modulation cycle, such as being shown in 305 of 3B figure.
This pulse-width signal that is come by this on-off controller 101 is shown to be provided to this current sensor 401, makes to be predicated suitable level so that before this switch S 1 conducting, obtain this VSH sampling at this pulse-width signal just.It should be noted that we expect that this is taken a sample and are obtained in this switch S 1 the preceding of real conducting, to avoid the effect of this damped oscillation 301.If use this pulse-width signal, then this current sensing device 401 is constituted to and kept this sampling before 1 conducting of this switch S.In the enforcement of real configuration, a different or preliminary pulse-width signal is provided to this current sensing device 401, to cause it to keep a value of taking a sample before conducting veritably, when finishing, preceding this pulse width modulation cycle that switches obtained to guarantee that this is taken a sample in this switch S 1.By this this pulse-width signal of current sensing device 401 relayings is possible, and it controls this switch S 1, is obtained before this switch S 1 activates to guarantee that this is taken a sample.Yet this needs this current sensing device 401 to comprise to be enough to drive the buffer circuits or the similar circuit of the grid of S1.In an embodiment, the preliminary pulse-width signal that is called PPWM (the 6th figure) is provided to this current sensing device 401, to guarantee in the preceding sampling of switching, as hereinafter doing further narration.Many embodiment different and that substitute are envisioned, to implement this current sensing device 401.
This boost converter 400 also comprises a ramp generator 403, and it produces ramp voltage VR, and it represents the increase or the rising of electric current among this inductor L when this switch S 1 conducting, as hereinafter doing further narration.This VR and VSH signal are provided to each input of a summation device 405, and this summation device 405 adds those voltage signals together, duplicate voltage signal VREP with what result from that its output provides.This VREP signal provides to a multiplier or gain square 407, this multiplier or gain square 407 are with a zoom factor " k " on this VREP signal times, and export a current feedback sensing signal VS '=k*VREP (wherein, this asterisk " * " representative is multiplied each other).This current feedback sensing signal VS ' is provided to this on-off controller 101 and replaces this VS signal.Less than one (1), and change this VREP signal and become this VS voltage of signals level on this zoom factor " k " typical case, as the flow through electric current of this switch S 1 of the voltage of this sense resistor of sensing RS when this switch S 1 conducting and representative.
5A-5C figure is respectively the curve chart of this ramp voltage VR, this sampling and holding circuit VSH and this summation and convergent-divergent voltage VREP and VS '.5A figure shows this ramp voltage VR that is produced representative increase generation of the electric current among this inductor L when this switch S 1 conducting by this ramp generator 403.In an embodiment, circuit box such as this ramp generator 403 itself monitor VIN, and (for example, inductance value=L) is known because the inductance value of this inductor, so produce that VR equals or ratio in VIN/L (wherein, oblique line "/" is represented division).As shown in the figure, VR is risen by the null value oblique line between time t1 and t2 in the mode of a linearity, and it is the oblique wave of electric current I between simulated time t1 and the t2 (RS).5B figure shows the VSH of the electric current of measuring among this inductor L that representative took a sample just before time t1, the electric current of its diode D1 that also equals to flow through is because this switch S 1 is turn-offed and in fact this inductor L and diode D1 connect.As shown in the figure, VSH is sampled during at whenabouts t1 in a certain voltage level, and by time t1 to t2 value of being maintained fixed.5C figure is shown in the VREP of the output of this summation device 405.Because VSH is the representative voltage of the initial current I (D1) of this diode D1 before this switch S 1 conducting just, and because the increase of the VR representative electric current of this inductor L after this switch S 1 conducting, so VREP is representative when flow through during conducting between time t1 and the t2 voltage of electric current of this switch S 1 of n pulse width modulation cycle.For each pulse width modulation cycle, operation repeats in a similar mode.VREP is with this zoom factor " k " convergent-divergent, and to produce VS ', it also is shown in 5C figure, and it is simulated between time t1 and t2 and goes up the previous voltage that produces in this sense resistor RS.
The 6th figure is more detailed signal and calcspar, the further details of the sequential that the sample maintenance of the electric current that output is measured DC boost converter 400 according to the sampling of the electric current of this diode of process D1 of an one exemplary embodiment of the present invention and with this direct current is relevant.The current mirror 601 of the diode D1 of a suitable zoom version that connects the electric current I (D1) that this sampling is provided to this current sensing device 401 is shown.In in the case, this current sensing device 401 is a sampling and holding device, when it was concluded into the next pulse width modulation cycle of Initiation when this preliminary pulse-width signal (or PPWM), the I (D1) and then keep to take a sample in its output of taking a sample constantly was as this VSH signal.This on-off controller 101 comprises one and latchs or trigger equipment or similar device, such as a D flip-flop 603, when its internal feedback control circuit (not shown) when it is judged Initiation next one pulse width modulation cycle, exports this preliminary pulse-width signal.This preliminary pulse-width signal is a numeral or binary signal or analog, and it directly is not used in the grid that drives this switch S 1.Be on the contrary, this preliminary pulse-width signal is through a buffer device 605 bufferings, and these buffer device 605 these pulse-width signals of output are to the grid of S1.In an embodiment, this buffer device 605 comprises a plurality of buffers that are connected in series or inverter or analog, so that this pulse-width signal is raise into suitable power level or driving force, to drive the grid of S1.This buffer device 605 is inserted a delay, and all (ns) orders of magnitude (for example, 20 nanoseconds) of nanosecond in full make this preliminary pulse-width signal be concluded before this pulse-width signal.In this way, just before this pulse-width signal is concluded with this switch S 1 of conducting, this current sensing device 401 receives these preliminary pulse-width signals, and a sampling of exporting this I (D1) signal is as this VSH signal.Use this preliminary pulse-width signal to guarantee sampling before switching with the control switching with the pulse-width signal of control sampling and delayed slightly.
This direct current is implemented a new solution to DC boost converter 400, in this scheme, replace being used for the electric current I (RS) that feedback loop is controlled among this toggle path, the electric current I (D1) of this boost converter 400 monitors or sampling is flowed through this diode D1, and replication stream is through the increase of the electric current of this inductor L, through the increase of this inductor current of this switching device shifter, and there are not stray inductance and damped oscillation noise that electric capacity caused with synthetic or analog stream again.Because avoid the damped oscillation of this current feedback information for the purpose of FEEDBACK CONTROL, overcome the T of pulse-width modulation work period
LEBCycle limit is so boost converter 400 can be operated under a work period of lacking very much.Particularly, first stage of each pulse width modulation cycle is terminated according to this VS ' signal, and it can be at this typical T
LEBProduce down any time before the end cycle, and make the pulse-width modulation work period of minimizing become possibility.Short work period makes this output voltage VO UT become possibility near the level of input voltage VIN, and itself and traditional direct current are not similar to DC boost converter.
This sense resistor RS can selectively be eliminated, and improves efficient by reducing power loss.This ramp generator 403, summation device 405 and this gain square 407 can be implemented in this on-off controller 101.Yet, it should be noted that the outside that extra means is arranged at this on-off controller 101 makes this on-off controller 101 keep not revising.If convergent-divergent (such as by group this on-off controller 101 of structure or pre-convergent-divergent or directly this VR of convergent-divergent and VSH voltage) suitably, this VREP voltage can directly be used, but not VS '.This direct current can be implemented on a common control chip or the integrated circuit (IC) DC boost converter 400.In an embodiment, for example, this on-off controller 101, this switch S 1, this current sensing device 401, this ramp generator 403, this summation device 405, this gain square 407, this current mirror 601 and being integrated of this diode D1 are to a shared control unit chip.So structure is particularly advantageous, because trigger, buffer, ramp generator, summation device, sampling and holding circuit and the current mirror usual means for implementing on an integrated circuit easily.
Though the present invention narrates in quite detailed mode with reference to some version of the present invention, yet other versions and variation are possible and are envisioned that.Haveing the knack of this operator should be appreciated that, it can use the idea that disclosed and specific embodiment as the design or the basis of revising other structures easily, being used to providing identical purpose of the present invention, and do not depart from by defined spirit of the present invention of appended claim and category.
Claims (18)
1. current replication circuit that is used for direct current to DC boost converter, it avoids a lead-edge-blanking (LEB) cycle limit, described direct current is by using an on-off controller that adopts Current Feedback Control to switch through the input voltage of an inductor and a diode and providing a pulse-width modulation (PWM) signal with the switch of control connection to described inductor to DC boost converter, and adjust an output voltage, described current replication circuit comprises:
A current sensor, the electric current of its sampling described inductor of process when described switch is shutoff, and the lucky sampling voltage that an indication inductor current was provided before described switch conduction;
A ramp generator, it provides a ramp voltage that duplicates the electric current increase of described inductor when described switch conduction; And
A summation device, it is added to described ramp voltage with described sampling voltage, to produce the voltage that duplicates of a feedback current control that is used in described on-off controller.
2. current replication circuit as claimed in claim 1 is characterized in that, described current sensor comprises a sampling and holding device, the electric current of its described inductor of sampling process before switching, and after switching, keep described sampling voltage.
3. current replication circuit as claimed in claim 2, it further comprises:
A current mirror, it is used to be connected to described diode, and it provides the image electric current of an indication through the electric current of described diode; And
Described sampling and holding device are connected to described current mirror, and its sampling and a sampling keeping described image electric current are as described sampling voltage.
4. current replication circuit as claimed in claim 3, it is characterized in that, described on-off controller provides a preliminary pulse-width signal, and a buffer receives described preliminary pulse-width signal and described pulse-width signal is provided, wherein, described sampling and holding device keep described sampling voltage described according to described preliminary pulse-width signal.
5. current replication circuit as claimed in claim 1 is characterized in that, the input voltage that described ramp generator basis is cut apart by the inductance value of described inductor, and produce described ramp voltage.
6. current replication circuit as claimed in claim 1, it further comprises a gain square, and it is multiplied by a zoom factor with the described voltage that duplicates, and provides a voltage sense signal to described on-off controller, to be used for Current Feedback Control.
7. a direct current is to direct current transducer, and it comprises:
An inductor, it has one first end and one second end, it is characterized in that, and described first termination is received the input voltage with respect to common node;
A diode, it has the anode and the negative electrode that are connected to one second end of described inductor;
A capacitor, it is connected between the negative electrode and described common node of described diode, and it produces an output voltage;
A switching device, it has one and is connected in second end of described inductor and the controlled current flow path between the described common node, and has a control input, when conducting, described switching device enables described current path, and when turn-offing, described switching device is forbidden described current path;
An on-off controller, it has the input of a received current sensing signal and one provides the output of pulse-width modulation control signal to the described control input end of described switching device;
A ramp generator, it provides a ramp signal, and described ramp signal has the slope that simulation increases through the electric current of described inductor when described switching device conducting;
A current sensor, it provides a current sampling signal, its indication when described switching device be turn-off and just before described switching device conducting through the current level of described diode; And
A summation device, it adds described oblique wave and current sampling signal together, with the reproducing signals that provides to be used in described current sensing signal.
8. direct current as claimed in claim 7 is characterized in that to direct current transducer described switching device comprises a mos field effect transistor.
9. direct current as claimed in claim 7 is characterized in that to direct current transducer described current sensor comprises a sampling and holding circuit, and its sampling current and its keep the current sampling signal of a sampling voltage as the sampled overcurrent of indication.
10. direct current as claimed in claim 7 is to direct current transducer, and it further comprises:
A current mirror, it is connected to described diode, and an image electric current is provided; And
Described current sensor comprises a sampling and holding circuit, and it is connected to described current mirror, its described image electric current and keep the current sampling signal of a sampling voltage as the indication electric current of taking a sample of taking a sample.
11. direct current as claimed in claim 10 is characterized in that direct current transducer:
Described on-off controller comprises a buffer, and it has the input and the output that described pulse-width modulation control signal is provided that receive preliminary pulse-width signal; And
Described sampling and holding circuit receive described preliminary pulse-width signal, and keep described current sampling signal according to described preliminary pulse-width signal.
12. direct current as claimed in claim 7 is to direct current transducer, it further comprises: a gain square, it is multiplied by a zoom factor with described reproducing signals, to produce described current sensing signal.
13. method of eliminating direct current to the lead-edge-blanking cycle limit of DC boost converter, described direct current switches one through the input voltage of an inductor and a diode and provide a pulse-width signal with the switch of control connection to described inductor to DC boost converter by using an on-off controller that adopts Current Feedback Control, and adjust an output voltage, described method comprises:
When described switch is an open circuit and just before described switch opens circuit the time, judge the current level of described inductor, and the current level signal of a correspondence is provided;
When described switch when being closed circuit, the electric current of synthetic described inductor increases and provides the ramp signal of a correspondence; And
Described current level and ramp signal are added together, to produce a current feedback sensing signal that offers described sampling controller.
14. method as claimed in claim 13, described method further comprises:
Produce a preliminary pulse-width signal; And
Cushion described preliminary pulse-width signal, so that pulse-width modulation control signal to be provided.
15. method as claimed in claim 14 is characterized in that, the step of the current level of the described inductor of described judgement comprises sampling current and keeps a current sampling according to described preliminary pulse-width signal.
16. method as claimed in claim 15 is characterized in that, described sampling and maintenance comprise the conversion electric current of taking a sample becomes a voltage sampling.
17. method as claimed in claim 15 is characterized in that, the preliminary pulse-width signal of described buffering comprises and postpones described pulse-width modulation control signal, to guarantee sampling before switching.
18. method as claimed in claim 13 is characterized in that, the inductance value that the electric current increase of described synthetic described inductor comprises according to described input voltage and described inductor produces described ramp signal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0413494.6 | 2004-06-16 | ||
| US10/965,345 | 2004-10-14 | ||
| US10/965,345 US20050280404A1 (en) | 2004-06-16 | 2004-10-14 | Current replication to avoid LEB restriction of DC-DC boost converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1761135A true CN1761135A (en) | 2006-04-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510079485 Pending CN1761135A (en) | 2004-06-16 | 2005-06-16 | Current replication to avoid leb restriction of dc-dc boost converter |
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| Country | Link |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101743526B (en) * | 2007-06-26 | 2012-08-22 | 维税-希力康克斯公司 | A current mode boost converter using slope compensation |
| CN103715898A (en) * | 2014-01-24 | 2014-04-09 | 矽力杰半导体技术(杭州)有限公司 | Feedback voltage sampling circuit, and feedback voltage blanking circuit and method |
| CN104638904A (en) * | 2013-11-06 | 2015-05-20 | 意法半导体研发(深圳)有限公司 | Peak-current-mode DC-DC converter |
| US9059632B2 (en) | 2008-03-24 | 2015-06-16 | O2Micro, Inc. | Controllers for DC to DC converters |
| CN106575921A (en) * | 2014-06-23 | 2017-04-19 | 微芯片科技公司 | Circuit and method for active crosstalk reduction in multiple-channel power supply controllers |
-
2005
- 2005-06-16 CN CN 200510079485 patent/CN1761135A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101743526B (en) * | 2007-06-26 | 2012-08-22 | 维税-希力康克斯公司 | A current mode boost converter using slope compensation |
| US9059632B2 (en) | 2008-03-24 | 2015-06-16 | O2Micro, Inc. | Controllers for DC to DC converters |
| CN104638904A (en) * | 2013-11-06 | 2015-05-20 | 意法半导体研发(深圳)有限公司 | Peak-current-mode DC-DC converter |
| CN104638904B (en) * | 2013-11-06 | 2018-01-19 | 意法半导体研发(深圳)有限公司 | Peak-current mode DC DC converters |
| CN103715898A (en) * | 2014-01-24 | 2014-04-09 | 矽力杰半导体技术(杭州)有限公司 | Feedback voltage sampling circuit, and feedback voltage blanking circuit and method |
| CN106575921A (en) * | 2014-06-23 | 2017-04-19 | 微芯片科技公司 | Circuit and method for active crosstalk reduction in multiple-channel power supply controllers |
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