CN1549434A - Output current adjustable electric current drive circuit - Google Patents
Output current adjustable electric current drive circuit Download PDFInfo
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- CN1549434A CN1549434A CNA031134076A CN03113407A CN1549434A CN 1549434 A CN1549434 A CN 1549434A CN A031134076 A CNA031134076 A CN A031134076A CN 03113407 A CN03113407 A CN 03113407A CN 1549434 A CN1549434 A CN 1549434A
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Abstract
The present invention relates to a current driving circuit capable of regulating output current intensity. Said circuit includes voltage amplitude-limiting synthesis module and voltage controlled current driving module. Said voltage amplitude-limiting synthesis module can be used for synthesizing the signal voltage and reference voltage, and can be used for controlling the voltage controlled current driving module to output the current relates to the reference voltage. Said current driving circuit can be used in the current driving stage of integrated circuit so as to utilize the regulation of reference voltage to set the output current of integrated circuit. Said circuit is simple in structure, and is easy to implement and its cost is low.
Description
The present invention relates to carry out the electronic circuit and the integrated circuit of current drives, especially can set the current drive of the integrated circuit of output current size.
Now, we AT STATION waiting room, airport airport lounge can see the various large-screen dot matrix display screens of forming by LED, issued vehicle order of classes or grades at school information, Flight Information etc. above; Charactron is the display device that a kind of tube core of the light-emitting diode that can independently be controlled by a plurality of (or many group) is formed the figure of eight, be used in bank and can show the interest rate of loans and deposits and current exchange rate etc., be used in securities broker company and can show current stock market, share price information etc., in addition, can also be used on the electronic instrument and to show various data etc.Light-emitting diode here and charactron belong to the galvanoluminescence device, and its luminosity has certain relation with electric current by this device; In addition, when the drive circuit of design micromotor, also to consider the relation of drive current and motor speed usually.
When designing general current drives integrated circuit, generally we can provide bigger current driving ability, but because final product is used difference, might need to regulate its driving force.For example, a general current driving circuit, its quiescent current driving force is 100mA, perhaps drive normally for the light-emitting diode of diameter 10mm, but for the light-emitting diode of diameter 3mm just might be because drive current is excessive the damage light-emitting diode; Charactron also is the same, and the electric current ability to bear of 0.5 inch charactron has only the part of 2 inches charactrons; Even the electric current ability to bear is out of question, we also need by the display brightness of adjusting drive current controlling light emitting device or the rotating speed of motor sometimes.
Current having two methods aspect the adjusting current driving ability: a kind of method is at current drives output serial connection current-limiting resistance, because the output voltage of current drives output is limited, so the big more then output current of the resistance of series resistor is more little; Another kind method is pulse-width modulation, promptly is the cycle with the certain hour, part-time output current only in each cycle, and all the other times are output current not, so the electric current output time accounts for the more little average output current that then obtains of the ratio in whole cycle in load more little.Preceding a kind of method, because each current drives output all will be connected in series current-limiting resistance and make the components and parts of entire circuit increase, not meeting current electronic product should exquisite small and exquisite main trend, general each charactron is wanted 7 resistance, if mixed decimal point then want 8 resistance, and the resistance of each resistance can not differ too big, otherwise display brightness is inhomogeneous.A kind of method in back makes some complexity of drive circuit itself because increase pulse-width modulation circuit, and because in pulse-width modulation process, drive current cuts in and out, on the one hand, the peak current of entire circuit is bigger, disturbs other circuit easily; On the other hand,, thereby produce more electromagnetic radiation, be unfavorable for environmental protection because square-wave signal includes a large amount of harmonic waves on frequency spectrum.
The objective of the invention is, a kind of adjustable current driving circuit of output current simple in structure, with low cost is provided.
Technical conceive of the present invention is: cmos fet pipe (transistor) is a kind of voltage control device, and its grid voltage can influence channel resistance, also just can control output current; So, the signal voltage and a certain reference voltage of input synthesized, by the channel resistance of resultant voltage control cmos device; Like this, just can influence the output current of cmos device by the size of regulating reference voltage.
In addition, cmos device comprises PMOS and NMOS, and both have similar operation principle, and both main difference are that electric polarity is opposite.CMOS belongs to 4 end-apparatus spares, comprising: grid (G end), source electrode (S end), drain electrode (D end), substrate (B end), but in general CMOS integrated circuit, substrate all has the connection of acquiescence.In the present invention, unless indicate separately, the substrate acquiescence of PMOS is connected to the positive power source terminal (VCC) of whole current driving circuit, and the substrate acquiescence of NMOS is connected to the earth terminal (GND) of whole current driving circuit.Consider the general characteristic of cmos digital integrated circuit, no longer distinguish the source electrode and the drain electrode of cmos device in the present invention; And carry out description in parallel for a plurality of similar cmos devices, will be equal to single cmos device in the present invention.Unless indicate separately, certain point voltage of the present invention is meant this voltage with respect to the earth terminal of whole current driving circuit.
Realize that technical scheme of the present invention is: current driving circuit comprises reference voltage input terminal (VREF), voltage amplitude limit synthesis module (11), voltage controlled current driver module (12).Voltage amplitude limit synthesis module synthesizes control voltage with the signal voltage and the reference voltage of input, and the voltage controlled current driver module is exported corresponding electric current according to the size of control voltage.Whole current driving circuit also comprises: positive power source terminal (VCC), earth terminal or be called negative power end (GND), signal voltage input (IN), current drives output (OUT).
In the such scheme, voltage amplitude limit synthesis module comprises an inverter of being made up of M1 (PMOS) and M2 (NMOS).The input of this inverter is after promptly the grid of M1 and M2 is connected, as the signal voltage input (IN) of whole current driving circuit; The output of this inverter (VC) after promptly the drain electrode of M1 and M2 is connected, is connected to the input of voltage controlled current driver module; The positive power source terminal of this inverter, i.e. the source electrode of M1 is connected to the positive power source terminal (VCC) of whole current driving circuit; The negative power end of this inverter, promptly the source electrode of M2 is connected to reference voltage input terminal (VREF).
In the such scheme, the voltage controlled current driver module comprises a M3 (PMOS), side circuit usually by a plurality of PMOS parallel connections obtaining enough current driving abilities, but when being used for current drives, a plurality of PMOS parallel connections are equal to the PMOS of single large-size.The grid of M3 is connected to the output (VC) of voltage amplitude limit synthesis module; The source electrode of M3 is connected to the positive power source terminal (VCC) of whole current driving circuit; The drain electrode of M3 is as the current drives output (OUT) of whole current driving circuit.
In such scheme, when reference voltage was 0V, the amplitude of the control voltage of voltage amplitude limit synthesis module output was the positive voltage of 0V to whole current driving circuit; When reference voltage was 1V, the amplitude of the control voltage of voltage amplitude limit synthesis module output was the positive voltage of 1V to whole current driving circuit.Because reference voltage is not simultaneously, the control voltage difference that grid obtained of the M3 of voltage controlled current driver module is so its channel resistance and output current all can be done corresponding variation.Actual cmos device belongs to non-linear electronic devices and components, and grid voltage also is subjected to the influence of source-drain voltage simultaneously to the influence of channel resistance.In the practical application circuit of technical scheme of the present invention and this scheme, reference voltage progressively increase within the specific limits can make the output current of voltage controlled current driver module progressively reduce, and is reduced to 0 up to electric current; When reference voltage is 0V (can also be negative value in theory, output current may be bigger, but this class situation generally can not occur in the side circuit, so needn't consider), the output current of voltage controlled current driver module reaches maximum.
Because PMOS and NMOS have similar operation principle, difference is that mainly electric polarity is opposite, so when needs are exported negative current or be called the suction electric current, as long as aforementioned circuit is done following adjustment: with the positive power source terminal of the inverter of voltage amplitude limit synthesis module based on the principle of technical solution of the present invention, be M4 (PMOS, former label is M1) source electrode, reconfiguration is to reference voltage input terminal (VRO, former label is VREF); With the negative power end of the inverter of voltage amplitude limit synthesis module, i.e. the source electrode of M5 (NMOS, former label is M2), reconfiguration is to the earth terminal (GND) of whole current driving circuit; Replace the former M3 (PMOS) of voltage controlled current driver module with M6 (NMOS), and the source electrode reconfiguration of M6 is arrived the earth terminal (GND) of whole current driving circuit.In this circuit, reference voltage progressively reducing within the specific limits can make the output negative current of voltage controlled current driver module progressively reduce, and is reduced to 0 up to electric current; (in theory can also be when reference voltage equals the positive voltage of whole current driving circuit greater than positive voltage, the output negative current may be bigger, but this class situation generally can not appear, so needn't consider in the side circuit), the output negative current of voltage controlled current driver module reaches maximum.The output negative current just sucks electric current, can be used for driving common positive charactron (anode of a plurality of light-emitting diodes of charactron links together, so can only carry out negative current drive at the negative electrode of each light-emitting diode); And the output positive current can be used to drive common cloudy charactron (negative electrode is shared, and the anode positive current drives).
In actual applications, whole current driving circuit can be an independently electronic circuit, also can be the current drive of certain integrated circuit.The signal voltage input of current drive can be directly connected to other functional module of this integrated circuit.For example, to the integrated circuit that a plurality of charactrons carry out dynamic reading scan, the signal voltage of its current drive is exactly the field data register that comes from the current charactron that activates.
In the actual integrated circuit based on such scheme, a plurality of current drive can a shared reference voltage input terminal, make each current drive have essentially identical current driving ability, can guarantee that so a plurality of luminescent devices that this integrated circuit drives have uniform luminosity, also can reduce needed outside connection of this integrated circuit simultaneously.For example, 8 current drive that drive a charactron can a shared reference voltage end, thus the size of each current drive output current of synchronization settings.In addition, reference voltage can come from a node of IC interior, is called reference voltage node, and this node can be driven by other functional module of integrated circuit.For example the output by D/A converter module DAC drives reference voltage node, just can set the size of reference voltage by the input data of revising D/A converter module DAC.
Based on technical scheme of the present invention, regulate the output current that reference voltage just can be set current driving circuit or integrated circuit current drive neatly, simple in structure, convenient and practical, with low cost.
The present invention is further illustrated below in conjunction with accompanying drawing.
Fig. 1 is the structural representation based on the current driving circuit of technical solution of the present invention.
Fig. 2 generally illustrates for cmos device.
Fig. 3 is the schematic diagram based on the current driving circuit of technical solution of the present invention.
Fig. 4 is the schematic diagram based on the current driving circuit of technical solution of the present invention output negative current.
Fig. 5 is the local hardware elementary diagram based on the integrated circuit of technical solution of the present invention.
Fig. 6 is the waveform schematic diagram at each key point of current driving circuit shown in Figure 3.
See Fig. 1, before the present invention, conventional current driving circuit comprises signal voltage input, current drives module, current drives output; Based on technical scheme of the present invention, current driving circuit also comprises reference voltage input terminal, voltage amplitude limit synthesis module (11), and the current drives module also is replaced by voltage controlled current driver module (12).
See Fig. 2, cmos device belongs to 4 end-apparatus spares, comprises PMOS and NMOS.Among the figure, the right up and down two diagrams is respectively the 4 ends diagram of PMOS and NMOS, and the left side two diagrams up and down is respectively the 3 ends diagram of PMOS and NMOS.In the present invention, the substrate of cmos device all adopts acquiescence to connect, and promptly the substrate of PMOS connects the positive power source terminal (VCC) of entire circuit, and the substrate of NMOS connects the earth terminal of entire circuit (GND), so adopted the 3 ends diagram of cmos device in the schematic diagram.
See Fig. 3, this is based on the schematic diagram of the current driving circuit of technical solution of the present invention.Voltage amplitude limit synthesis module comprises the inverter that is made of M1 (PMOS) and M2 (NMOS), the source electrode of M2 in the inverter is connected to reference voltage input terminal (VREF), the input of inverter is exactly signal voltage input (IN), and the output of inverter (VC) is connected to the input of voltage controlled current driver module.The voltage controlled current driver module comprises M3 (PMOS), and its output is exactly current drives output (OUT).The signal voltage of input can be opened or the output current of close current drive circuit, and when signal voltage was low level, output current always was closed and is 0; When signal voltage is high level, if reference voltage is 0V, then M2 can pull down to 0V with the grid of M3, the bigger electric current of output so the M3 channel resistance is less, if reference voltage is 1V, then the multipotency of M2 pulls down to 1V with the grid of M3, the slightly little electric current of output so the M3 channel resistance is big slightly.In sum, the Push And Release of the applied signal voltage of current driving circuit decision output current, and the size of reference voltage decision output current: reference voltage increases, and output current reduces, and makes the output current of whole current driving circuit adjustable.
See Fig. 4, this is based on the schematic diagram of the current driving circuit of technical solution of the present invention output negative current, and its operation principle is identical with the description at Fig. 3, only electric polarity difference to some extent.Voltage amplitude limit synthesis module comprises the inverter that is made of M4 (PMOS) and M5 (NMOS), the source electrode of M4 is connected to reference voltage input terminal (VRO), the voltage controlled current driver module comprises M6 (NMOS), its output is exactly current drives output (OUT), only exports negative current and just sucks electric current.The signal voltage of input can be opened or the output current of close current drive circuit, and when signal voltage was high level, output current always was closed and is 0; When signal voltage is low level, if reference voltage equals the positive voltage of whole current driving circuit, suppose that this positive voltage is 5V, then M4 can move 5V on the grid with M6, suck bigger electric current so the M6 channel resistance is less, if reference voltage is 4V, then move 4V on the grid of multipotency of M4 with M6, suck slightly little electric current so the M6 channel resistance is big slightly.In sum, the Push And Release of the applied signal voltage of current driving circuit decision output current, and the size of reference voltage decision output current: reference voltage reduces, and output current reduces.
See Fig. 5, be based on the local hardware elementary diagram of the integrated circuit of technical solution of the present invention in the frame of broken lines.Having 8 groups of current drive based on technical solution of the present invention in this integrated circuit (CHIP), only drawn among the figure two groups, is respectively the 8th group that comprises M11, M12, M13 first group and comprise M81, M82, M83.The input signal of each current drive comes from other functional module of this integrated circuit; The current drives output of each current drive all is connected to the external pin (OUT1, OUT8, other pin does not draw in the drawings) of integrated circuit; The reference voltage end of all current drive all links together, and is connected to the external pin (VREF) of integrated circuit.This integrated circuit also comprises positive supply pin (VCC) and the grounding pin (GND) that the overall situation is shared.In addition, for the reference voltage of acquiescence is provided under the situation that does not have external reference voltage at integrated circuit, this integrated circuit also comprises the drop-down setting device of a reference voltage M0 (NMOS plays a pull down resistor at this).Like this, if external reference voltage is not provided in application circuit, this integrated circuit still can be by the default setting output current; And when needs are adjusted the output current size, can also connect pull-up resistor R1 at the external pin (VREF) of this integrated circuit, by the size of R1 and M0 dividing potential drop decision reference voltage; If there is not the drop-down setting device of reference voltage M0, then resistance R 1 is selected 3 end adjustable resistances usually for use, and two stiff ends connect positive power line and earth connection respectively, and adjustable end connects reference voltage pin (VREF).The following stiff end of R1 links to each other with dotted line with earth connection (GND) among the figure, illustrates that this connecting line is optional.This integrated circuit is when using, can save the serial connection current-limiting resistance in the conventional scheme, and the current drives output of each current drive is directly connected Light-Emitting Diode (L1, L8 among the figure) or each anode of cloudy charactron altogether, adjust the resistance of the pull-up resistor R1 of reference voltage, just can set the size of reference voltage, thereby change the electric current that flows through in the luminescent device (L1, L8 among the figure), with the brightness of coupling and adjustment luminescent device.
See Fig. 6, the waveform of each key point of displayed map 3 circuit successively from top to bottom: the voltage waveform of signal voltage input (IN), the voltage waveform of reference voltage input terminal (VREF), the voltage waveform of voltage amplitude limit synthesis module output (VC), the current waveform of current drives output (OUT) (with luminescent device as load).
Progress along with the epoch, people to electronic product except functional requirement, some accessory claims have been arranged: environmental protection, energy-conservation, exquisite, small and exquisite, flexible or the like again, these requirements that can better satisfy people based on the current driving circuit and the relevant integrated circuit of technical solution of the present invention, and simple in structure, be easy to realize, with low cost.
Claims (10)
1, the adjustable current driving circuit of a kind of output current has signal voltage input and current drives output, it is characterized in that:
Comprise a reference voltage input terminal;
Comprise a voltage amplitude limit synthesis module, be used for signal voltage and reference voltage are synthesized control voltage;
Comprise a voltage controlled current driver module, be used for exporting corresponding electric current according to the size of control voltage.
2, current driving circuit according to claim 1 is characterized in that: voltage amplitude limit synthesis module comprises an inverter, and the negative power end of this inverter is connected to reference voltage input terminal.
3, current driving circuit according to claim 1 is characterized in that: voltage amplitude limit synthesis module comprises an inverter, and the positive power source terminal of this inverter is connected to reference voltage input terminal.
4, according to claim 2 or 3 described current driving circuits, it is characterized in that: the inverter in the voltage amplitude limit synthesis module is made of a PMOS device and a nmos device, the grid of two devices is connected, and as the signal voltage input of whole current driving circuit.
5, current driving circuit according to claim 2 is characterized in that: the voltage controlled current driver module comprises the PMOS device, and its source electrode is connected to the positive power source terminal of current driving circuit, and drain electrode is as the current drives output of current driving circuit.
6, current driving circuit according to claim 3 is characterized in that: the voltage controlled current driver module comprises nmos device, and its source electrode is connected to the earth terminal of current driving circuit, and drain electrode is as the current drives output of current driving circuit.
7, the adjustable integrated circuit of a kind of current drive output current has the current drives output, it is characterized in that:
IC interior comprises a reference voltage node;
At least comprise a voltage amplitude limit synthesis module and a voltage controlled current driver module.
8, integrated circuit according to claim 7 is characterized in that: comprise the drop-down setting device of a reference voltage NMOS in the integrated circuit, the drain electrode of this NMOS is connected to reference voltage node, and source electrode is connected to the earth terminal of integrated circuit.
9, integrated circuit according to claim 7 is characterized in that: comprise in the integrated circuit to draw on the reference voltage and set device PMOS, the drain electrode of this PMOS is connected to reference voltage node, and source electrode is connected to the positive power source terminal of integrated circuit.
10, according to claim 7,8 or 9 described integrated circuits, it is characterized in that: reference voltage node is connected with the external pin of integrated circuit, is used in the outside size of adjusting reference voltage of integrated circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031134076A CN1549434A (en) | 2003-05-08 | 2003-05-08 | Output current adjustable electric current drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031134076A CN1549434A (en) | 2003-05-08 | 2003-05-08 | Output current adjustable electric current drive circuit |
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| CN1549434A true CN1549434A (en) | 2004-11-24 |
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| CNA031134076A Pending CN1549434A (en) | 2003-05-08 | 2003-05-08 | Output current adjustable electric current drive circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7902935B2 (en) | 2007-09-07 | 2011-03-08 | Huawei Technologies Co., Ltd. | Bias circuit and voltage-controlled oscillator |
| CN103150990A (en) * | 2011-09-28 | 2013-06-12 | 合肥工业大学 | Light-emitting diode (LED) display screen constant-current driving circuit with plurality of mirror image ratios |
| CN105576950A (en) * | 2015-12-31 | 2016-05-11 | 杭州士兰微电子股份有限公司 | Dynamic regulation apparatus for driving signal and driving method and driving system thereof |
| CN108599570A (en) * | 2018-06-04 | 2018-09-28 | 电子科技大学 | A kind of circuit with dynamic regulation current limit threshold |
-
2003
- 2003-05-08 CN CNA031134076A patent/CN1549434A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7902935B2 (en) | 2007-09-07 | 2011-03-08 | Huawei Technologies Co., Ltd. | Bias circuit and voltage-controlled oscillator |
| CN103150990A (en) * | 2011-09-28 | 2013-06-12 | 合肥工业大学 | Light-emitting diode (LED) display screen constant-current driving circuit with plurality of mirror image ratios |
| CN103150990B (en) * | 2011-09-28 | 2014-08-06 | 合肥工业大学 | Light-emitting diode (LED) display screen constant-current driving circuit with plurality of mirror image ratios |
| CN105576950A (en) * | 2015-12-31 | 2016-05-11 | 杭州士兰微电子股份有限公司 | Dynamic regulation apparatus for driving signal and driving method and driving system thereof |
| CN105576950B (en) * | 2015-12-31 | 2019-02-01 | 杭州士兰微电子股份有限公司 | Dynamic regulation device and its driving method and drive system for driving signal |
| CN108599570A (en) * | 2018-06-04 | 2018-09-28 | 电子科技大学 | A kind of circuit with dynamic regulation current limit threshold |
| CN108599570B (en) * | 2018-06-04 | 2019-10-22 | 电子科技大学 | A kind of circuit with dynamic regulation current limit threshold |
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