Electric pressure converter
Technical field
The utility model relates to a kind of electric pressure converter, and particularly relevant for a kind of electric pressure converter that produces the output signal of stablizing ripple.
Background technology
Please refer to Figure 1A, Figure 1A illustrates existing electric pressure converter 100.Electric pressure converter 100 comprises driver 110, logical operation circuit 120, comparator C MP1, transistor M1, M2, inductance L 1, capacitor C 1 and resistance R 1 and R2.In electric pressure converter 100, comparator C MP1 produces by logical operation circuit 120 and driver 110 in regular turn and drives signal DRV1 and DRV2 by the comparative result of comparison reference signal REF and feedback signal VFB.In addition, transistor M1 receives supply voltage VIN.
In electric pressure converter 100, when comparator C MP1 compares feedback signal VFB when being lower than reference signal REF, transistor M1 comes conducting a period of time according to driving signal DRV1, and output signal VOUT correspondence is risen, afterwards transistor M1 according to driving that signal DRV1 disconnects and transistor M2 according to driving signal DRV2 conducting, and output signal VOUT descends when feedback signal VFB is lower than reference signal REF again, and transistor M1 comes conducting a period of time according to driving signal DRV1 again.
When the equivalent cascade resistance ESR of capacitor C 1 is too low, please refer to the movement oscillogram of the electric pressure converter 100 shown in Figure 1B.Ripple part on the feedback signal VFB wherein will be very not obvious, and cause the ripple phenomenon on the output signal VOUT to present very unsure state, and reduced the quality of output signal VOUT.
The utility model content
The utility model provides a kind of electric pressure converter, effectively produces to have the output signal of stable ripple.
The utility model proposes a kind of electric pressure converter, comprise fixedly ON time signal generator, the first transistor, transistor seconds, inductance, feedback circuit and ripple injection circuit.Fixedly the ON time signal generator produces first and drives signal and the second driving signal.The first transistor has first end, second end and control end, and its first termination is received supply voltage, and its control end receives first and drives signal, and its second end is coupled to the phase terminal of electric pressure converter.Transistor seconds has first end, second end and control end.First end of transistor seconds is coupled to phase terminal, and the control end of transistor seconds receives second and drives signal, and second end of transistor seconds is coupled to reference to earthed voltage.Inductance is serially connected between the output of phase terminal and electric pressure converter, produces output signal on the output of electric pressure converter.Feedback circuit carries out dividing potential drop at output signal and generates feedback signal with the feedback end at electric pressure converter.The ripple injection circuit is coupled to feedback end and phase terminal.The voltage that the ripple injection circuit obtains between feedback end and phase terminal produces ripple injection signal.Wherein, fixedly the ON time signal generator injects signal, output signal and reference signal to produce first and second driving signal according to ripple.
In an embodiment of the present utility model, above-mentioned ripple injection circuit comprises first resistance, first electric capacity, second resistance, second electric capacity and operational amplifier.First end of first resistance is coupled to phase terminal, and first end of first electric capacity is coupled to second end of first resistance.Second end of first electric capacity is coupled to feedback end.First end of second resistance is coupled to second end of first resistance.First end of second electric capacity is coupled to second end of second resistance, and second end of second electric capacity is coupled to feedback end.Operational amplifier has first input end, second input and output, and its first input end and second input are coupled to first end and second end of second resistance respectively.Operational amplifier produces ripple injection signal according to voltage difference, and operational amplifier also passes through its output transmission and injects extremely fixedly ON time signal generator of signal.
In an embodiment of the present utility model, above-mentioned ripple injection circuit also comprises buffer.Buffer is serially connected in second electric capacity and couples between the path of feedback end, and wherein the input of buffer is coupled to feedback end, and the output of buffer is coupled to second end of second electric capacity.
In an embodiment of the present utility model, above-mentioned ripple injection circuit also comprises bleeder circuit.Bleeder circuit is serially connected in first resistance and couples between the path of phase terminal, in order to carry out dividing potential drop at the voltage on the phase terminal.
In an embodiment of the present utility model, above-mentioned fixedly ON time signal generator comprises adder and comparator.Adder injects signal at ripple and feedback signal is carried out add operation.Comparator couples adder, compares to produce comparative result in order to output and reference signal at adder.Wherein, fixedly the ON time signal generator produces first and second according to comparative result and drives signal.
In an embodiment of the present utility model, above-mentioned fixedly ON time signal generator also comprises logical operation circuit and driver.Logical operation circuit couples the output of comparator.Logical operation circuit receive and at comparative result to carry out logical operation.Driver couples logical operation circuit, drives signal in order to receive and to produce first and second according to the operation result of logical operation.
In an embodiment of the present utility model, electric pressure converter also comprises output capacitance.One end of output capacitance is coupled to the output of electric pressure converter, and its other end is coupled to reference to earthed voltage.
In an embodiment of the present utility model, above-mentioned output capacitance is the electric capacity of low equivalent cascade resistance.
In an embodiment of the present utility model, above-mentioned feedback circuit comprises first resistance and second resistance.One end of first resistance is coupled to the output of electric pressure converter, and its other end is coupled to feedback end.One end of second resistance is coupled to feedback end, and its other end is coupled to reference to earthed voltage.
Based on above-mentioned, the utility model produces ripple injection signal by feedback end and the voltage between phase terminal that the ripple injection circuit obtains electric pressure converter, and provides ripple to inject extremely fixedly ON time signal generator of signal.Fixedly the ON time signal generator and according to ripple inject signal, output signal and reference signal produce this first and second drive signal.The output signal that electric pressure converter is produced has stable ripple partly, advances the signal quality of the output signal that is produced with the booster tension transducer.
For above-mentioned feature and advantage of the present utility model can be become apparent, hereinafter for embodiment, and conjunction with figs. is described in detail below.
Description of drawings
Figure 1A illustrates existing electric pressure converter 100;
Figure 1B illustrates the movement oscillogram of electric pressure converter 100;
Fig. 2 illustrates the schematic diagram of the electric pressure converter 200 of the utility model one embodiment;
Fig. 3 illustrates the schematic diagram of the electric pressure converter 300 of another embodiment of the utility model;
Fig. 4 illustrates the utility model schematic diagram of the electric pressure converter 400 of an embodiment again.
Description of reference numerals:
100,200,300,400: electric pressure converter;
210,310,410: fixing ON time signal generator;
220,320,420: the ripple injection circuit;
230,430: feedback circuit;
110,311,411: driver;
120,312,412: logical operation circuit;
313,413: adder;
431: bleeder circuit;
M1, M2: transistor;
CMP1: comparator;
L1: inductance;
PHASE: phase terminal;
OT: output;
FB: feedback end;
GND: with reference to earthed voltage;
R1, R2: resistance;
VINJ: inject signal;
C1, C11, C12: electric capacity;
OP1: operational amplifier;
BUF: buffer;
VOUT: output signal;
CO: output capacitance;
DRV1, DRV2: drive signal;
REF: reference signal;
VFB: feedback signal.
Embodiment
Please refer to Fig. 2, Fig. 2 illustrates the schematic diagram of the electric pressure converter 200 of the utility model one embodiment, and wherein, electric pressure converter 200 is the buck electric pressure converter.Electric pressure converter 200 comprises fixedly ON time signal generator 210, transistor M1 and M2, inductance L 1, ripple injection circuit 220 and feedback circuit 230.Fixedly ON time signal generator 210 produces and drives signal DRV1 and DRV2.Transistor M1 has first end, second end and control end, and first termination of transistor M1 is received supply voltage VIN, and the control end of transistor M1 receives and drives signal DRV1, and second end of transistor M1 is coupled to the phase terminal PHASE of electric pressure converter 200.Transistor M2 has first end, second end and control end equally.First end of transistor M2 is coupled to phase terminal PHASE, and the control end of transistor M2 receives and drives signal DRV2, and second end of this transistor M2 is coupled to reference to earthed voltage GND.According to driving signal DRV1 and DRV2 with conducting or disconnection, wherein, transistor M1 and M2 be conducting simultaneously not respectively for transistor M1 and M2.
Inductance L 1 is serially connected between the output OT of phase terminal PHASE and electric pressure converter 200.The output OT of electric pressure converter 200 goes up and produces output signal VOUT.230 of feedback circuits carry out dividing potential drop at output signal VOUT and generate feedback signal VFB with the feedback end FB at electric pressure converter 200.In the present embodiment, feedback circuit 230 comprises resistance R 1 and R2.First end of resistance R 1 is coupled to output OT, and second end of resistance R 1 is coupled to feedback end FB, and first end of resistance R 2 is coupled to feedback end FB, and second end of resistance R 2 then is coupled to reference to earthed voltage GND.
Ripple injection circuit 220 is coupled to feedback end FB and phase terminal PHASE.Ripple injection circuit 220 obtains the voltage difference between feedback end FB and phase terminal PHASE, and provides injection signal VINJ extremely fixedly ON time signal generator 210 according to the voltage difference between feedback end FB and phase terminal PHASE.
In the present embodiment, ripple injection circuit 220 comprises resistance R 1, R2, capacitor C 11, C12, operational amplifier OP1 and buffer BUF.First end of resistance R 1 is coupled to phase terminal PHASE, and second end of resistance R 1 is coupled to first end of capacitor C 11 and first end of resistance R 2, and second end of capacitor C 11 is coupled to the output of buffer BUF.Second end of resistance R 2 is coupled to first end of capacitor C 12, and second end of capacitor C 12 is coupled to the output of buffer BUF.Two inputs of operational amplifier OP1 are coupled to second end of resistance R 1 and second end of resistance R 2 respectively.The output of operational amplifier OP1 then produces and injects signal VINJ, and transmits and inject extremely fixedly ON time signal generator 210 of signal VINJ.
In addition, the input of buffer BUF is coupled to feedback end FB, and wherein, buffer BUF can be the buffer (unit gain buffer) of single gain.
The voltage that operational amplifier OP1 senses according to resistance R 1, R2 and capacitor C 11, C12 produces and injects signal VINJ.The resistance value of resistance R 1, R2 and capacitor C 11, C12 capacitance can be set according to the frequency of output signal VOUT.
Electric pressure converter 200 comprises output capacitance CO in addition.The end of output capacitance CO is coupled to the output OT of electric pressure converter 200, and its other end is coupled to reference to earthed voltage GND.And output capacitance CO can be the electric capacity of low equivalent cascade resistance.
Please refer to Fig. 3, Fig. 3 illustrates the schematic diagram of the electric pressure converter 300 of another embodiment of the utility model.Electric pressure converter 300 comprises fixedly ON time signal generator 310, transistor M1 and M2, inductance L 1, ripple injection circuit 320 and feedback circuit 330.In the present embodiment, ripple injection circuit 320 and feedback circuit 330 the circuit structure formula with the ripple injection circuit 220 of last embodiment and feedback circuit 230 respectively are identical, seldom give unnecessary details at this.It should be noted that in the present embodiment that pulse-width modulation signal generator 310 comprises driver 311, logical operation circuit 312, adder 312 and comparator C MP1.Logical operation circuit 312 couples the output of comparator C MP1, and the comparative result that receives and produce at comparator C MP1 is to carry out logical operation.Driver 311 couples logical operation circuit 312.Driver 311 receives and generates according to the operation result of the performed logical operation of logical operation circuit 312 and drives signal DRV1 and DRV2.Adder 313 is carried out add operation in order to injection signal VINJ and the feedback signal VFB that produces at ripple injection circuit 320, comparator C MP1 then couples adder 313, and the output that performed add operation produces at adder and reference signal REF compare, and produce comparative result according to this.
Subsidiary one carries, and reference signal REF is a pre-set signal, and reference signal REF can be set according to the actual working state of electric pressure converter 300 by the designer.
With the next Fig. 4 that please refer to, Fig. 4 illustrates the utility model schematic diagram of the electric pressure converter 400 of an embodiment again.Electric pressure converter 400 comprises fixedly ON time signal generator 410, transistor M1 and M2, inductance L 1, ripple injection circuit 420 and feedback circuit 430.Different with last embodiment, the ripple injection circuit 420 of electric pressure converter 400 also comprises bleeder circuit 431.Bleeder circuit 431 is serially connected in resistance R 1 and couples between the path of phase terminal PHASE, in order to carry out dividing potential drop at the voltage on the phase terminal PHASE.That is to say, bleeder circuit 431 can carry out dividing potential drop at the voltage on the phase terminal PHASE earlier, provides voltage to the voltage difference sensing circuit of resistance R 1, R2, capacitor C 11, C12 and the construction of operational amplifier OP1 institute on the phase terminal PHASE after the dividing potential drop to carry out the action of voltage sensing again.
Subsidiary one carries, after the feedback end FB that mentions among above-mentioned a plurality of embodiment and phase terminal PHASE can be the electric pressure converter chipization, and the pin position on the electric pressure converter chip.That is to say that the ripple injection circuit is by connecting existing pin position on the electric pressure converter chip, just the output signal that electric pressure converter is produced has stable ripple, promotes the quality of output signal.
In sum, the utility model is used as producing the foundation that ripple injects signal by the voltage difference of obtaining between feedback end and phase terminal, and by inject according to feedback signal and ripple signal with, come to compare with reference signal, and produce driving signal to control transistorized conducting or disconnection according to this.Thus, the output signal that produces of electric pressure converter can have stable ripple partly.
It should be noted that at last: above each embodiment is not intended to limit only in order to the technical solution of the utility model to be described; Although have been described in detail with reference to the utility model of aforementioned each embodiment, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps some or all of technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the scope of each embodiment technical scheme of the utility model.