CN101111987A - Step-up/step-down regulator circuit and liquid crystal display device using the same - Google Patents
Step-up/step-down regulator circuit and liquid crystal display device using the same Download PDFInfo
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- CN101111987A CN101111987A CNA2005800474488A CN200580047448A CN101111987A CN 101111987 A CN101111987 A CN 101111987A CN A2005800474488 A CNA2005800474488 A CN A2005800474488A CN 200580047448 A CN200580047448 A CN 200580047448A CN 101111987 A CN101111987 A CN 101111987A
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Abstract
A step-up/step-down regulator circuit wherein a switch (N2) has a terminal connected to an end of an inductor (L1), another terminal grounded, and a control terminal connected to an end of a switch (N1). In this way, performing an open/close control of the switch (N1) can indirectly perform an open/close control of the switch (N2), thereby solving the problem that the structure and operation of a switch control circuit will be complicated when the switching between step-up and step-down operations is realized.
Description
Technical field
The present invention relates to input voltage boost or step-down producing the step-up/down voltage regulator circuit of required output voltage, and relate to liquid crystal display in conjunction with this step-up/down voltage regulator circuit.
Background technology
Conventionally, open and proposed polytype step-up/down voltage regulator circuit, be used for to input voltage boost or step-down to produce required output voltage (for example, seeing patent disclosure 1).
Fig. 6 shows the circuit diagram of conventional step-up/down voltage regulator circuit example.As shown in the figure, conventional step-up/down voltage regulator circuit comprises ON-OFF control circuit a1, step-down switching a2, inductor a3, diode a4 and a5, smmothing capacitor a6 and boosted switch a7, and be arranged to and promote or reduce input voltage vin from DC power supply a8, to produce required output voltage V out, then it is fed to load 9.
More specifically, as the step-up/down voltage regulator circuit of above-mentioned configuration in, ON-OFF control circuit a1 monitors output voltage V out.When the needs boost operations, ON-OFF control circuit a1 switches on and off boosted switch a7, so that output voltage V out is promoted to desirable value.During boost operations, step-down switching a2 keeps conducting.On the other hand, when the needs reduced pressure operation, ON-OFF control circuit a1 switches on and off step-down switching a2, so that output voltage V out is reduced to desirable value.During reduced pressure operation, boosted switch a7 keeps disconnecting.
In addition, except as the step-up/down voltage regulator circuit of above-mentioned configuration, also have other known step-up/down voltage regulator circuits, some of them are called Cuk circuit, Zeta circuit and SEPIC circuit (seeing that Fig. 7 (a) is to 7 (c)).
Summary of the invention
The problem to be solved in the present invention
Really, than boosting and the routine configuration of reduced pressure operation by between boosting of separate being provided with and lowering and stabilizing blood pressure device circuit, switching as required to carry out, as above the step-up/down voltage regulator circuit of configuration allow boost and reduced pressure operation between simply switch, and can not cause decline that the output voltage V out that transient phenomena cause takes place when switching owing to circuit, dash or overshoot and vibration down, thereby help to improve transient response, reduce current drain and raise the efficiency.
Yet, as above the configuration the step-up/down voltage regulator circuit in, boost and reduced pressure operation between switching require ON-OFF control circuit a1 to switch on and off step-down switching a2 and boosted switch a7.This causes configuration and the operation more complicated of ON-OFF control circuit a1.
In addition, in the step-up/down voltage regulator circuit of as above configuration, though appear at the waveform (so-called continuous mode) that the switching voltage Vsw of inductor a3 one end should have the square wave of the continuous appearance shown in Fig. 8 (a) ideally, but when load is lighter or non-loaded, the output current of step-up/down voltage regulator circuit may reduce, thereby reduce coil current IL on the whole, cause the disturbed waveform that is called vibration (so-called non-continuous mode) shown in Fig. 8 (b).In this non-continuous mode, switch should disconnect during under undesirable vibration The noise of occurring, switching may be subjected to controlling mistakenly, thereby causes the output voltage instability.
On the other hand, Fig. 7 (a) also need all to be configured to capacitor Cb as energy storage device to the conventional step-up/down voltage regulator circuit shown in 7 (c) except that smmothing capacitor Ca.Therefore, these circuit need unnecessary bigger circuit arrangement when integrated.
Consider above-mentioned inconvenience, the purpose of this invention is to provide a kind of step-up/down voltage regulator circuit and in conjunction with the liquid crystal display of this circuit, though described step-up/down voltage regulator circuit has easy configuration, can be easily and correctly boost and reduced pressure operation between switch.
The means of dealing with problems
To achieve these goals, according to an aspect of the present invention, a kind of step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and comprises: first switching device, and the one end is connected with the input voltage input terminal; Inductor, the one end is connected with the other end of first switching device; The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device; First diode, its negative electrode is connected with the other end of first switching device, and anode is connected with the normal voltage input terminal; Second diode, its anode is connected with the other end of inductor, and negative electrode is connected with voltage output end; Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal; The feedback voltage generation device is used for producing feedback voltage according to output voltage; Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And switch controlling device, its open and close first switching device is to reduce the output (first configuration) from error amplification device.This fairly simple configuration itself can be easily and correctly boost and reduced pressure operation between switch.
In the step-up/down voltage regulator circuit of above-mentioned first configuration, preferably adopt FET as first and second switching devices (second configuration).Than the configuration of adopting bipolar transistor etc. as first and second switching devices, this configuration provides higher voltage transitions efficient.
In the step-up/down voltage regulator circuit of above-mentioned first configuration, preferably first switching device, error amplification device and switch controlling device are encapsulated in the semiconductor device, and with other assemblies from external mounting (3rd configuration) to this semiconductor device.This configuration allows the power supply IC that will use lowering and stabilizing blood pressure device circuit always to use as the semiconductor integrated equipment, and need not any modification.
According to a further aspect of the invention, a kind of step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and comprises: first switching device, and the one end is connected with the input voltage input terminal; Inductor, the one end is connected with the other end of first switching device; The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device; The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal, and its current capacity is designed to lower than the current capacity of first switching device; First diode, its negative electrode is connected with the other end of first switching device, and anode is connected with the normal voltage input terminal; Second diode, its anode is connected with the other end of inductor, and negative electrode is connected with voltage output end; Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal; The feedback voltage generation device is used for producing feedback voltage according to output voltage; Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close the 3rd switching device (the 4th configuration) complementally with it.
According to a further aspect of the invention, a kind of step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and comprises: first switching device, and the one end is connected with voltage input end; Inductor, the one end is connected with the other end of first switching device; The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device; The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal; Diode, its anode is connected with the other end of inductor, and negative electrode is connected with voltage output end; Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal; The feedback voltage generation device is used for producing feedback voltage according to output voltage; Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close the 3rd switching device (the 5th configuration) complementally with it.
According to a further aspect of the invention, a kind of step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and comprises: first switching device, and the one end is connected with the input voltage input terminal; Inductor, the one end is connected with the other end of first switching device; The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device; The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal; The 4th switching device, the one end is connected with the other end of inductor, and the other end is connected with voltage output end; Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal; The feedback voltage generation device is used for producing feedback voltage according to output voltage; Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close third and fourth switching device (the 6th configuration) complementally with it.
Though itself is fairly simple in above-mentioned the 4th to the 6th configuration, can be easily and correctly boost and reduced pressure operation between switch.In addition, these configurations suitably prevent the oscillatory occurences of appearance when load is light, thereby help to realize more stable boosting and reduced pressure operation.
According to a further aspect in the invention, a kind of liquid crystal display comprises: DC power supply; The DC/DC transducer is with the conversion equipment of opposing and changing from the output of DC power supply; And display panels, it is driven by the output voltage from the DC/DC transducer.Here, liquid crystal display has the step-up/down voltage regulator circuit of one of above-mentioned first to the 6th configuration, as DC/DC transducer (the 7th configuration).In this configuration, no matter be higher than from the input voltage of DC power supply or be lower than required output voltage, the DC/DC transducer all keeps producing required output voltage.This has stablized the display operation of liquid crystal display.
Beneficial effect of the present invention
As mentioned above, for step-up/down voltage regulator circuit according to the present invention with in conjunction with the liquid crystal display of this circuit, though they are own fairly simple, unlike the circuit or the equipment that adopt crew-served a plurality of switching devices, but by an open and close single switch device, just can be easily and correctly boost and reduced pressure operation between switch.Can successfully obtain required output voltage like this.
Also can suitably prevent the oscillatory occurences of appearance when load is light, thereby realize more stable boosting and reduced pressure operation.
Description of drawings
Fig. 1 shows the block diagram of the ios dhcp sample configuration IOS DHCP of specific implementation liquid crystal display of the present invention.
Fig. 2 shows the circuit diagram of the DC/DC transducer 2 of first embodiment of the invention.
Fig. 3 shows the circuit diagram of the DC/DC transducer 2 of second embodiment of the invention.
Fig. 4 shows the circuit diagram of the DC/DC transducer 2 of third embodiment of the invention.
Fig. 5 shows the circuit diagram of the DC/DC transducer 2 of fourth embodiment of the invention.
Fig. 6 shows the circuit diagram of the conventional example of step-up/down voltage regulator circuit.
Fig. 7 shows the circuit diagram of other conventional examples of step-up/down voltage regulator circuit.
Fig. 8 shows the figure how oscillatory occurences appears when light in load.
Reference numerals list
1 DC power supply
2 DC/DC transducers (step-up/down voltage regulator circuit)
3 TFT liquid crystal panels
The IC1 semiconductor device
The CTRL ON-OFF control circuit
N1 N-channel MOS field-effect transistor (first switching device)
N2 N-channel MOS field-effect transistor (second switch device)
N3a, N3b N-channel MOS field-effect transistor (the 3rd switching device)
N4 N-channel MOS field-effect transistor (the 4th switching device)
The ERR error amplifier
E1 direct voltage source (band gap power circuit)
The T1 input terminal
The T2 lead-out terminal
The T3 feedback terminal
The T4 control terminal
L1 inductor (coil)
D1, the D2 diode
The C1 smmothing capacitor
R1, the R2 resistor
Embodiment
The example that how to apply the present invention to the DC/DC transducer has been discussed in following description, this DC/DC converter incorporates is in liquid crystal display, be used to change the output voltage of DC power supply, the voltage that drives with other parts (specifically being TFT (thin-film transistor) liquid crystal panel) that produce equipment.
Fig. 1 shows the block diagram of ios dhcp sample configuration IOS DHCP of specific implementation the present invention's (particularly, this part as at the power-supply system of TFT liquid crystal panel) liquid crystal display.As shown in the figure, the liquid crystal display of present embodiment has: DC power supply 1, as the power supply of this device interior; DC/DC transducer 2 is as the device of conversion from the output of DC power supply 1; And TFT liquid crystal panel 3, as the display unit in the liquid crystal display.
2 conversions of DC/DC transducer to produce required output voltage V out, are fed to TFT liquid crystal panel 3 with output voltage V out from the input voltage vin of DC power supply 1 then.
Fig. 2 shows the circuit diagram (part illustrates as block diagram) of the DC/DC transducer 2 of first embodiment of the invention.As shown in the figure, the DC/DC transducer 2 of present embodiment comprises: N-channel MOS (metal oxide silicon) field-effect transistor N1 and N2; Inductor (coil) L1; Diode D1 and D2; Smmothing capacitor C1; Resistor R 1 and R2; Error amplifier ERR; Direct voltage source E1; With ON-OFF control circuit CTRL.
As shown in the figure, in the DC/DC of present embodiment transducer 2, transistor N1, error amplifier ERR, direct voltage source E1 and ON-OFF control circuit CTRL all are encapsulated among the silicon monolithic semiconductor device IC1, other assemblies from external mounting to semiconductor device IC1.Adopt this configuration, the power supply control IC that the DC/DC transducer 2 of present embodiment allows to use lowering and stabilizing blood pressure device circuit always is used as semiconductor device IC1, and need not any modification.
In addition, in practice, except said modules, semiconductor device IC1 also comprises kinds of protect circuit (for example, low input causes trouble-saving circuit, overheating protection circuit, circuit overcurrent protection and short-circuit protection circuit).But, because these circuit are not directly related with the present invention, so less than it not being elaborated or describing.Be also to be understood that other any ways enforcement the present invention that can adopt except that this specifically described mode.For example, in case of necessity, the assembly on from external mounting to semiconductor device IC1 can be integrated into the IC1.
The drain electrode of transistor N1 is connected with input voltage input terminal (lead-out terminal of DC power supply 1) by the input terminal T1 of semiconductor device IC1, and input voltage vin is applied to the drain electrode of transistor N1.The source electrode of transistor N1 is connected with the end of inductor L1, the grid of transistor N2 and the negative electrode of diode D1 by the lead-out terminal T2 of semiconductor device IC1.The plus earth of diode D1.The drain electrode of transistor N2 is connected with the other end of inductor L1 and the anode of diode D2.The source ground of transistor N2.The negative electrode of diode D2 is connected with voltage output end (power input terminal of TFT liquid crystal panel 3), and on the one hand by smmothing capacitor C1 ground connection, series circuit (this series circuit is configured for the feedback voltage generation circuit according to the output voltage V out generation feedback voltage Vfb) ground connection by forming again on the other hand by resistor R 1 and R2.Node between resistor R 1 and the R2 is used as the lead-out terminal of feedback voltage Vfb, and is connected with the reversed input terminal (-) of error amplifier ERR by the feedback terminal T3 of semiconductor device IC1.Non-inverting input (+) of error amplifier ERR and direct voltage source E1 are (for example, the band gap power circuit) plus end connects, and the reference voltage V ref that is used for the desired value of definite output voltage V out is applied to non-inverting input (+) of error amplifier ERR.The negative terminal ground connection of direct voltage source E1.The lead-out terminal of error amplifier ERR is connected with the error signal input terminal of ON-OFF control circuit CTRL.Control signal output ends of ON-OFF control circuit CTRL is connected with the grid of transistor N1.
In the DC/DC transducer 2 of as above configuration, error amplifier ERR amplifies and exports the poor of feedback voltage Vfb and reference voltage V ref, and ON-OFF control circuit CTRL open and close transistor N1 is to reduce the output from error amplifier ERR.
Here, when transistor N1 conducting (being in closure state), the grid potential of transistor N2 rises to about input voltage vin, and this makes transistor N2 conducting (being in closure state).Therefore, electric current is along the path i1 inductor L1 that flows through, and this causes that power storage is in inductor L1.During the conducting state of transistor N1 and N2, if charge storage in smmothing capacitor C1, then electric current flows to voltage output end from smmothing capacitor C1.In addition, in this state, because the electromotive force on the other end of inductor L1 is almost the same with earth potential low, so diode D2 is in reverse-bias state.Therefore, there is not electric current from smmothing capacitor C1 inflow transistor N2.
Subsequently, when transistor N1 ends (being in open mode), occur inverse electromotive force voltage among the inductor L1, this inverse electromotive force voltage causes that electric energy stored discharges along path i2 among the inductor L1.Therefore, the grid potential of transistor N2 becomes negative potential.Like this, after transistor N1, transistor N2 is by (being in open mode).Under this state, electric current flows along path i2, thereby flows into TFT liquid crystal panel 3 from voltage output end, and flows into earth terminal through smmothing capacitor C1.Thereby smmothing capacitor C1 is charged.
As mentioned above, the DC/DC transducer of present embodiment 2 promotes or reduces input voltage vin producing required output voltage V out, and comprises: first switching device (transistor N1), and the one end is connected with the input voltage input terminal; Inductor L1, the one end is connected with the other end of first switching device; Second switch device (transistor N2), the one end is connected with the other end of inductor L1, the other end and ground connection, control end is connected with the other end of first switching device; Diode D1, its negative electrode is connected plus earth with the other end of the first switching device N1; Diode D2, its anode is connected with the other end of inductor L1, and negative electrode is connected with voltage output end; Capacitor C1, the one end is connected other end ground connection with voltage output end; (resistor R 1 R2), is used for producing feedback voltage Vfb according to output voltage V out the feedback voltage generation device; Error amplifier ERR is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage Vref; And switch controlling device CTRL, it is opened or closed first switching device, to reduce the output from error amplifier ERR.
In this configuration, by the transistor N1 of open and close as first switching device, open and close is as the transistor N2 of second switch device indirectly.
Therefore, DC/DC transducer 2 for present embodiment, by utilizing switch controlling device CRTL suitably to control the driving duty ratio (the conducting state time period is divided by the cut-off state time period) of the transistor N1 that is used as first switching device, more specifically, be reduced to below the duty ratio that is used for reduced pressure operation and and increase to more than the duty ratio that is used for boost operations by driving duty ratio it, even the employing easy configuration, also can be easily and correctly boost and step-down between switch.Therefore, in the liquid crystal display that is combined with this DC/DC transducer 2, no matter be higher than or be lower than required output voltage V out, all can obtain required output voltage V out always from the input voltage vin of DC power supply 1.Therefore, even be 16V and under the situation that input voltage changes, also can obtain required output voltage in 6 to 18V scope at the level of required output voltage V out, thus the display operation of stabilizing liquid crystal display floater 3.
In addition, as shown in Figure 2, the DC/DC transducer 2 of present embodiment makes field-effect transistors N1 and N2 as first and second switching devices.Than the configuration of using bipolar transistor etc. as first and second switching devices, this configuration provides higher voltage transitions efficient.But this does not also mean that configuration of the present invention is implemented in restriction by any way; That is, can use bipolar transistor etc. as first and second switching devices.
The DC/DC transducer 2 of second embodiment of the invention is described below with reference to Fig. 3.Fig. 3 shows the circuit diagram (part illustrates as block diagram) of the DC/DC transducer 2 of second embodiment.As shown in the figure, the DC/DC transducer 2 of present embodiment has DC/DC transducer 2 configuration much at one with above-mentioned first embodiment.Therefore, the similar portions that in first embodiment, occurs with public designated, and no longer repeat explanation to it; That is, in the following description, emphasis is described the exclusive feature of present embodiment (additionally being provided with the anti-locking apparatus of vibration).
The DC/DC transducer 2 of present embodiment has the N-channel MOS field-effect transistor N3a (the 3rd switching device) that additionally is encapsulated among the semiconductor device IC1, the anti-locking apparatus of the vibration of the oscillatory occurences when preventing that load is lighter or non-loaded.
The drain electrode of transistor N3a is connected with the source electrode of transistor N1.The source ground of transistor N3a.The grid of transistor N3a is connected with control signal output ends of ON-OFF control circuit CTRL.
In addition, transistor N3a should be designed to have the minimum current capacity that is enough to extract the vibration noise, and the vibration noise occurs with very little current forms.This helps to prevent unnecessarily to increase chip area or reduces conversion efficiency inadequately.Particularly, in the DC/DC of present embodiment transducer 2, transistor N3a has the current capacity lower than transistor N1, and big electric current need pass through from transistor N1.More specifically, transistor N3a is designed to have the 1/N (in the present embodiment, 1/10) of the gate area of transistor N1.
As mentioned above, ON-OFF control circuit CTRL open and close transistor N1, reducing output from error amplifier ERR, and open and close transistor N3a complementally simultaneously.
In this configuration, when load is lighter or non-loaded,, thereby reduce coil current on the whole even output current reduces, the disturbed waveform (so-called non-continuous mode) that is called vibration in aforesaid Fig. 8 (b) occurs, and also the vibration noise can be transferred to ground wire.This switch that helps to prevent transistor N2 is subjected to wrong control, thereby helps to realize more stable boosting and reduced pressure operation.
The DC/DC transducer 2 of third embodiment of the invention is described below with reference to Fig. 4.Fig. 4 shows the circuit diagram (part illustrates as block diagram) of the DC/DC transducer 2 of the 3rd embodiment.As shown in the figure, the DC/DC transducer 2 of present embodiment has DC/DC transducer 2 configuration much at one with above-mentioned first and second embodiment.Therefore, the similar portions that in first or second embodiment, occurs with public designated, and no longer repeat explanation to it; That is, in the following description, emphasis is described the exclusive feature of present embodiment (replacing the synchronous rectification of diode D1).
The DC/DC transducer 2 of present embodiment has the N-channel MOS field-effect transistor N3b (the 3rd switching device) that additionally is encapsulated among the semiconductor device IC1, as an alternative the anti-locking apparatus of vibration of the synchronous rectificating device of diode D1 and the oscillatory occurences when preventing that load is lighter or non-loaded.
The drain electrode of transistor N3b is connected with the source electrode of transistor N1.The source ground of transistor N3b.The grid of transistor N3b is connected with control signal output ends of ON-OFF control circuit CTRL.
In addition, transistor N3b is designed to have the current capacity comparable with the current capacity of transistor N1.More specifically, transistor N3b is designed to have the gate area comparable with the gate area of transistor N1.
As mentioned above, ON-OFF control circuit CTRL open and close transistor N1, reducing output from error amplifier ERR, and open and close transistor N3b complementally simultaneously.
In this configuration, in above-mentioned second embodiment, when load is lighter or non-loaded, even output current reduces, thereby reduce coil current on the whole, the disturbed waveform (so-called non-continuous mode) that is called vibration in aforesaid Fig. 8 (b) occurs, and also can transfer to ground wire via the transistor N3b noise that will vibrate.This switch that helps to prevent transistor N2 is subjected to wrong control, thereby helps to realize more stable boosting and reduced pressure operation.In addition, in this configuration, the transistor N3b lower than the conducting resistance of diode D1 with conducting resistance replaces diode D1, thereby can reduce the electrical piano power loss at diode D1 two ends among second embodiment.This helps to improve the conversion efficiency of equipment.In addition,, can omit a diode, promptly from the diode D1 of external mounting than above-mentioned second embodiment.This helps to reduce the circuit scale of equipment.
The DC/DC transducer 2 of fourth embodiment of the invention is described with reference to Fig. 5 at last.Fig. 5 shows the circuit diagram (part illustrates as block diagram) of the DC/DC transducer 2 of the 4th embodiment.As shown in the figure, the DC/DC transducer 2 of present embodiment has DC/DC transducer 2 configuration much at one with above-mentioned the 3rd embodiment.Therefore, the similar portions that in the 3rd embodiment, occurs with public designated, and no longer repeat explanation to it; That is, in the following description, emphasis is described the exclusive feature of present embodiment (replacing the synchronous rectification of diode D2).
The DC/DC transducer 2 of present embodiment has the N-channel MOS field-effect transistor N4 (the 4th switching device) that additionally is encapsulated among the semiconductor device IC1, the synchronous rectificating device of diode D2 as an alternative.
The drain electrode of transistor N4 is connected with the other end of inductor L1.The source electrode of transistor N4 is connected with voltage output end.The grid of transistor N4 is connected with control signal output ends of ON-OFF control circuit CTRL by the control terminal T4 of semiconductor device IC1.
As mentioned above, ON-OFF control circuit CTRL open and close transistor N1, reducing output from error amplifier ERR, and complementally open and close transistor N3b and N4 simultaneously.
In this configuration, the transistor N4 lower than the conducting resistance of diode D2 with conducting resistance replaces diode D2, thereby can reduce the electrical piano power loss at diode D2 two ends among the 3rd embodiment.This helps to improve the conversion efficiency of equipment.
Should be appreciated that, more than the term " complementally " that uses in the description of second to the 4th embodiment not only contain the conducting of transistor N1 and by with the conducting of transistor N3a, N3b and N4 with by the situation of opposite generation accurately, and consider from the angle that prevents through current with for other, also contain the conducting of transistor N1 and by with the conducting of transistor N3a, N3b and N4 with by on the contrary but have predetermined delay and situation about taking place.
The foregoing description is all at the situation that applies the present invention to DC/DC transducer 2, and wherein DC/DC transducer 2 produces the driving voltage Vout of TFT liquid crystal panel 3 by the input voltage vin of conversion from DC source 1.But this does not also mean that application limitations of the present invention in these embodiment.Should be appreciated that the present invention can be widely used in lifting or reduce input voltage to produce the step-up/down voltage regulator circuit of required output voltage.
The specifically described mode, can also adopt other any ways to implement the present invention as embodiment except above, and allow in the present invention's spirit scope, to carry out any change and modification.
Industrial applicability
The present invention is very useful aspect simplification step-up/down voltage regulator circuit.
Claims (7)
1. a step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and described step-up/down voltage regulator circuit comprises:
First switching device, the one end is connected with the input voltage input terminal;
Inductor, the one end is connected with the other end of first switching device;
The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device;
First diode, its negative electrode is connected with the other end of first switching device, and anode is connected with the normal voltage input terminal;
Second diode, its anode is connected with the other end of inductor, and negative electrode is connected with voltage output end;
Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal;
The feedback voltage generation device is used for producing feedback voltage according to output voltage;
Error amplification device is used to amplify the poor of feedback voltage and predetermined reference voltage; And
Switch controlling device, its open and close first switching device is to reduce the output from error amplification device.
2. step-up/down voltage regulator circuit as claimed in claim 1, wherein first and second switching devices are FET.
3. step-up/down voltage regulator circuit as claimed in claim 1, wherein
First switching device, error amplification device and switch controlling device are encapsulated in the semiconductor device, and with on other assemblies are from the external mounting to the semiconductor device.
4. a step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and described step-up/down voltage regulator circuit comprises:
First switching device, the one end is connected with the input voltage input terminal;
Inductor, the one end is connected with the other end of first switching device;
The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device;
The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal, and its current capacity is designed to lower than the current capacity of first switching device;
First diode, its negative electrode is connected with the other end of first switching device, and anode is connected with the normal voltage input terminal;
Second diode, its anode is connected with the other end of inductor, and negative electrode is connected with voltage output end;
Capacitor, the one end is connected with voltage output end, and the other end is connected with the normal voltage input terminal;
The feedback voltage generation device is used for producing feedback voltage according to output voltage;
Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And
Switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close the 3rd switching device complementally with it.
5. a step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and described step-up/down voltage regulator circuit comprises:
First switching device, the one end is connected with the input voltage input terminal;
Inductor, the one end is connected with the other end of first switching device;
The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device;
The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal;
Diode, its anode is connected with the other end of inductor, and negative electrode is connected with the terminal that is applied in output voltage;
Capacitor, the one end is connected with the terminal that is applied in output voltage, and the other end is connected with the normal voltage input terminal;
The feedback voltage generation device is used for producing feedback voltage according to output voltage;
Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And
Switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close the 3rd switching device complementally with it.
6. a step-up/down voltage regulator circuit produces required output voltage by promoting or reducing input voltage, and described step-up/down voltage regulator circuit comprises:
First switching device, the one end is connected with the input voltage input terminal;
Inductor, the one end is connected with the other end of first switching device;
The second switch device, the one end is connected with the other end of inductor, and the other end is connected with the normal voltage input terminal, and control end is connected with the other end of first switching device;
The 3rd switching device, the one end is connected with the other end of first switching device, and the other end is connected with the normal voltage input terminal;
The 4th switching device, the one end is connected with the other end of inductor, and the other end is connected with the terminal that is applied in output voltage;
Capacitor, the one end is connected with the terminal that is applied in output voltage, and the other end is connected with the normal voltage input terminal;
The feedback voltage generation device is used for producing feedback voltage according to output voltage;
Error amplification device is used for amplifying and exporting the poor of feedback voltage and predetermined reference voltage; And
Switch controlling device, its open and close first switching device, reducing output from error amplification device, and open and close third and fourth switching device complementally with it.
7. liquid crystal display comprises:
DC power supply;
The DC/DC transducer is with the conversion equipment of opposing and changing from the output of DC power supply; And
Display panels, it is driven by the output voltage from the DC/DC transducer,
Wherein be provided with as the described step-up/down voltage regulator circuit of one of claim 1 to 6, as described DC/DC transducer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP050070/2005 | 2005-02-25 | ||
| JP2005050070 | 2005-02-25 | ||
| JP213738/2005 | 2005-07-25 |
Publications (1)
| Publication Number | Publication Date |
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| CN101111987A true CN101111987A (en) | 2008-01-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2005800474488A Pending CN101111987A (en) | 2005-02-25 | 2005-10-21 | Step-up/step-down regulator circuit and liquid crystal display device using the same |
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| CN (1) | CN101111987A (en) |
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| CN102651200A (en) * | 2011-03-30 | 2012-08-29 | 京东方科技集团股份有限公司 | Liquid crystal backlight driving circuit |
| CN103187874A (en) * | 2011-12-27 | 2013-07-03 | 立锜科技股份有限公司 | Step-up converter with step-down regulation capability and step-down regulation method thereof |
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| CN107276400A (en) * | 2017-08-11 | 2017-10-20 | 株洲宏达微电子科技有限公司 | A kind of Buck Boost application circuits |
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