CN1201475C - Coil driver with power supply tracking and over-voltage protecting functions - Google Patents
Coil driver with power supply tracking and over-voltage protecting functions Download PDFInfo
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- CN1201475C CN1201475C CNB011100591A CN01110059A CN1201475C CN 1201475 C CN1201475 C CN 1201475C CN B011100591 A CNB011100591 A CN B011100591A CN 01110059 A CN01110059 A CN 01110059A CN 1201475 C CN1201475 C CN 1201475C
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- coil
- pulse generator
- operational amplifier
- power supply
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Abstract
The present invention relates to a coil drive circuit with the functions of power supply tracing and overvoltage protection. An overvoltage protection circuit is connected with a drive circuit of a loop, wherein the drive circuit is composed of transistors, the overvoltage protection circuit is composed of and operational amplifier linked with switch elements. When the coil generates back electromotive force high voltage because of polarity reversal, the high voltage signal is fed back to the operational amplifier to control and conduct the switch elements so that the transistors of the drive circuit are conducted to lead the back electromotive force high voltage to an earth terminal.
Description
Technical field
The invention relates to a kind of coil driver of tool power supply tracking and over-voltage protecting function, refer to especially a kind ofly have, and can change the drive circuit of the voltage limiting value of overvoltage crowbar according to power supply voltage variation.
Background technology
At present, when exchanging, coil power polarity produces the back electromotive force high pressure, even this coil is connected with a protective circuit, to limit the back electromotive force high pressure of unexpected generation, to reach the purpose of protection coil driver for avoiding brushless DC fan or d.c. motor.
Seeing also shown in Figure 4ly, is to be an overvoltage crowbar of commonly using 60, and it is applied in the direct current brush-less fan control circuit, and this control circuit is to include:
One hall sensor 50 is in order to the reversal situation of two coil L1, L2 on the detecting brush-less fan;
One amplifier 51 is the outputs that are connected in this hall sensor 50, in order to amplify the detection signal of this hall sensor 50;
One pulse generator 52 is the outputs that are connected in this amplifier 51;
A group or more drive circuit 53 is to be made up of transistor Q1, Q2 respectively, and each transistorized base stage is the output that is connected to above-mentioned pulse generator 52 respectively, and its collection utmost point then is connected to two groups of coil L1, L2 of brush-less fan respectively;
A group or more overvoltage crowbar 60, each overvoltage crowbar 60 are that wherein this overvoltage crowbar 60 is to be Zener diode between transistor Q1, the Q2 collection utmost point and the earth terminal that is connected to above-mentioned drive circuit 53 relatively;
Two coil L1, the L2 of above-mentioned DC fan is in moment moment of switching, because of the reversal meeting produces a back electromotive force high pressure, and this back electromotive force high pressure will be to the injection of the transistor Q1 of the drive circuit 53 collection utmost point, this moment is because of the Zener diode Z1 collapse conducting ground connection of this protective circuit 60, the back electromotive force high pressure will import earth terminal through Zener diode Z1, can guarantee that this transistor Q1 can not burn out; Even yet if for after the working power reduction of giving this DC fan, will be a fixed value because of Zener diode Z1, the Z2 collapse conducting voltage of this overvoltage crowbar 60, make the output voltage values of transistor Q1, Q2 can and not reduce along with the power supply reduction.
Please refer to shown in Fig. 5 A, the B, is when representing that respectively control circuit is in different operating voltage, the output state of its collector terminal of transistor Q1 of drive circuit 53.In Fig. 5 A, the operating voltage of control circuit is 12 volts, and the collapse conducting voltage of Zener diode Z1 is VZ, and when the back electromotive force high pressure produced, Z1 promptly can be because of instantaneous pressure collapses conducting, with the voltage limit of transistor Q1 collector terminal in the VZ definite value; And in Fig. 5 B, in case the operating voltage of control circuit is reduced to 5 volts, and the back electromotive force high pressure is when producing, and Zener diode Z1 is still the collapse conducting, but the voltage of transistor Q1 collector terminal still is limited in the VZ definite value.
Again; at present in the brush DC fan; it is the controlled function that has additional many fan functionality; for example by Control work power source voltage value; can change the rotation speed change of fan, but as described above, commonly use back electromotive force high-pressure limit that protective circuit 60 only produces coil in a fixed value VZ; can't change its restriction pressure value according to different working powers, so can't meet the described application feature of present reality.
Summary of the invention
For this reason, main purpose of the present invention provides a kind of coil driver of tool power supply tracking and over-voltage protecting function, and wherein this overvoltage crowbar can change along with working power pressure value, relatively limiting coil back-emf voltage size.
For reaching above-mentioned purpose, the coil driver of a kind of tool power supply tracking and over-voltage protecting function of the present invention, it includes a hall sensor, is to connect one group of coil, in order to detect the reversal situation of this group coil;
One pulse generator is to connect this hall sensor, and wherein this pulse generator has two outputs;
Two overvoltage crowbars is characterized in that,
Wherein each overvoltage crowbar is to include an operational amplifier, a switching transistor, it is to be connected to the output of each operational amplifier and two outputs of pulse generator respectively that the inverting input input of each operational amplifier has operational voltage value and reference pressure value, each switching transistor;
Two drive circuits, wherein each drive circuit is to be driving transistors, each driving transistors is to be connected to the non-inverting input of aforementioned each operational amplifier and the output of aforementioned each coil and aforementioned pulse generator respectively;
Wherein when aforementioned driving transistors transfers cut-off state to by conducting state, when coil produces the back electromotive force high pressure because of polarity inversion, this back electromotive force high pressure is the non-inverting input of back coupling to each operational amplifier, makes each operational amplifier output high levle that switching transistor conducting and then controlling and driving transistor turns are used the back electromotive force high pressure is directed to ground connection.
Each switching transistor and driving transistors are to be all field-effect transistor, wherein each switching transistor is connected with the output of each operational amplifier with source terminal, its drain end is connected with the gate terminal of driving transistors, its gate terminal is to be connected with the output of pulse generator, each driving transistors is normal phase input end and each coil that is connected to each operational amplifier with its drain again, its source electrode is to be ground connection, and its gate terminal is the output that is connected to aforementioned pulse generator.
Wherein the gate terminal of each switching transistor is to see through an inverter to be connected to pulse generator.
Wherein the gate terminal of each switching transistor is to see through an inverter to be connected to pulse generator.
Wherein the gate terminal of each driving transistors is to see through the output that a current-limiting resistance is connected to pulse generator.
Wherein the drain end of each driving transistors is the anode tap that is connected to a diode respectively, and the cathode terminal of each diode is the cathode terminal that is connected to a Zener diode again, and the anode tap of this Zener diode is to be connected to power end.
Description of drawings
For making your auditor can further understand architectural feature of the present invention and other purposes, below in conjunction with accompanying drawing to the detailed description of the invention as after, wherein:
Fig. 1 is the user mode circuit diagram of one embodiment of the invention.
Fig. 2 A, B: be voltage analysis curve chart of the present invention.
Fig. 3 is the user mode circuit diagram of another embodiment of the present invention.
Fig. 4 is a user mode circuit diagram of commonly using protective circuit.
Fig. 5 A, B: be the voltage analysis curve chart of commonly using protective circuit.
Embodiment
At first seeing also shown in Figure 1ly, is the control circuit schematic diagram that is applied to the brush DC fan for the present invention, and wherein this control circuit is to include:
One hall sensor 10 is two coil L1, the L2 reversal situations in order to the detecting DC fan;
One amplifier 11 is the outputs that are connected in this hall sensor 10, in order to amplify the detection signal of this hall sensor 11;
One pulse generator 12 is the outputs that are connected in this amplifier 11;
Two overvoltage crowbars the 20, the 21st are connected to two output VA, the VB of this pulse generator 12 respectively;
Two drive circuits 13,14; each drive circuit the 13, the 14th in this enforcement adopts field-effect transistor N1, N2; its gate terminal (Gate) is connected to above-mentioned overvoltage crowbar 20,21 respectively; the drain end (Drain) of each field-effect transistor N1, N2 be connect brush-less fan respectively respectively organize coil L1, L2; wherein each field-effect transistor also can be replaced by bipolar transistor (BJT); if when adopting bipolar transistor; then base terminal is connected to above-mentioned pulse generator, and collector terminal then is connected to and respectively organizes coil.
Wherein two groups of overvoltage crowbars 20,21 include respectively:
One operational amplifier OP1, OP2, the non-inverting input of each operational amplifier is the drain end that is connected to field-effect transistor N1, the N2 of drive circuit 13,14 respectively, the inverting input of each operational amplifier has then been imported a restriction pressure value, wherein this restriction pressure value is for working power pressure drop VDD adds a reference pressure value VREF, and reference pressure value VREF is for adjusting.
Two switch element S1, S2, in present embodiment, each switch element is to adopt field-effect transistor (FET), the gate terminal of each field-effect transistor is to see through an inverter INV1 respectively, INV2 is connected to two output VA to pulse generator 12, VB, each field-effect transistor S1, the source terminal of S2 then is connected to two operational amplifier OP1 respectively, the output of OP2, each drain end is to be connected to drive circuit 13 respectively again, field-effect transistor N1 in 14, the gate of N2 is again respectively with a current-limiting resistance R1, R2 is connected in inverter INV1, INV2 and drive circuit 13, field-effect transistor N1 in 14, between the gate of N2.
Following elder generation only illustrates as circuit operation with the field-effect transistor N1 of an overvoltage crowbar 21 collocation drive circuits 13; when this hall sensor 10 senses the reversal of coil L1; promptly export a hall signal, see through amplifier 11 and amplify the signal of this high and low accurate position of pulse generator 12 generations of back control in order to Driving Field effect transistor N1.
When the output VA of pulse generator 12 changes into low level by high levle; even the former field-effect transistor N1 that is in conducting state transfers cut-off state to; and coil L1 no longer moves; coil L1 will produce the drain end of a back electromotive force high pressure at field-effect transistor N1 in switching moment; the drain that connects field-effect transistor N1 because of the non-inverting input of this amplifier OP1; so its accurate position is greater than the restriction pressure value (VDD+VREF) of inverting input; thereby export the source electrode that a high levle signal gives field-effect transistor S1 in the overvoltage crowbar 20; simultaneously because this pulse generator 12VA output is to be low level; so field-effect transistor S1 will obtain a high potential conducting because of gate; also make simultaneously the field-effect transistor N1 conducting of drive circuit 13; thus; back electromotive force high pressure on the coil L1 can be derived by earth terminal through field-effect transistor N1; when field-effect transistor N1 drain voltage during less than the restriction pressure value (VDD+VREF) of amplifier OP1; this amplifier OP1 output is transmitted low level; at this moment; because of producing 12 device output VA, pulse wave still exports electronegative potential; so still conducting of field-effect transistor S1, but field-effect transistor N1 then transfers cut-off state in the drive circuit 13.
In like manner, when coil L2 reverse, the action of the amplifier OP2 in the overvoltage crowbar 21, field-effect transistor S2, inverter INV2 all is same as above-mentioned, states so no longer praise.
Please refer to shown in Fig. 2 A, the B, is when representing that respectively control circuit is in different operating voltage, the output waveform of the field-effect transistor N1 drain end of drive circuit 13.In Fig. 2 A, the operating voltage VDD of control circuit is 12 volts, and reference pressure value VREF is 5.5 volts, and when the back electromotive force high pressure produced, the voltage of field-effect transistor N1 drain end then was limited in 17.5 volts; And in Fig. 2 B; in case the operating voltage VDD of control circuit reduces to 5 volts; and when reference pressure value VREF still is 5.5 volts; the back electromotive force high pressure of field-effect transistor N1 drain end then is limited in 10.5 volts; as can be known, this overvoltage crowbar 21 is the limits values that determine the back electromotive force high pressure according to the height of operating voltage VDD behind comparison diagram 2A, the B.
Please refer to shown in Figure 3, be to be another preferred embodiment of the present invention, it wherein is the cathode terminal that distinctly is connected with diode D1, D2 at the drain end of field-effect transistor N1, the N2 of each drive circuit 13,14 again, the anode tap of two diode D1, D2 is the cathode terminal that is connected to a Zener diode Z1 jointly, and the anode tap of this Zener diode Z1 then is to be connected to power end VDD.
The circuit of present embodiment is collapse conducting voltage VZ value exclusive disjunction amplifier OP1, the reference pressure value VREF of OP2 by decision Zener diode Z1, to adjust the restriction pressure value of back electromotive force high pressure.If the VZ value less than the VREF value, then when coil L1, L2 produce the back electromotive force high pressure because of reversal, can make at first conducting of Zener diode Z1, and this high pressure is derived by power end; Anti-, greater than the VREF value, then when the back electromotive force high pressure produced, this back electromotive force then moved by operational amplifier OP1, OP2 collocation field-effect transistor S1, S2 according to previous embodiment, is derived by earth terminal as if the VZ value.And the user can be according to its actual circuit condition; set VZ value and VREF value and select wherein one group of overvoltage crowbar; reach the protection purpose as mentioned above; the present invention forms the purpose that member reaches coil driver in the protection fan control circuitry with simple circuit; can be along with the increase and decrease of power supply with restriction and fix its output voltage values; so demand of the visual all kinds of coil drivers of this protective circuit (not having the coil driver that flows brush-less fan) as d.c. motor or direct current; adjust its pressure limiting reference value; can reach the pressure limiting purpose of following the trail of power source change, and then improve the useful life of drive circuit.
Claims (6)
1. the coil driver of a tool power supply tracking and over-voltage protecting function, it includes a hall sensor, is to connect one group of coil, in order to detect the reversal situation of this group coil;
One pulse generator is to connect this hall sensor, and wherein this pulse generator has two outputs;
Two overvoltage crowbars is characterized in that,
Wherein each overvoltage crowbar is to include an operational amplifier, a switching transistor, it is to be connected to the output of each operational amplifier and two outputs of pulse generator respectively that the inverting input input of each operational amplifier has operational voltage value and reference pressure value, each switching transistor;
Two drive circuits, wherein each drive circuit is to be driving transistors, each driving transistors is to be connected to the non-inverting input of aforementioned each operational amplifier and the output of aforementioned each coil and aforementioned pulse generator respectively;
Wherein when aforementioned driving transistors transfers cut-off state to by conducting state, when coil produces the back electromotive force high pressure because of polarity inversion, this back electromotive force high pressure is the non-inverting input of back coupling to each operational amplifier, makes each operational amplifier output high levle that switching transistor conducting and then controlling and driving transistor turns are used the back electromotive force high pressure is directed to ground connection.
2. the coil driver of a kind of tool power supply tracking and over-voltage protecting function according to claim 1; it is characterized in that; each switching transistor and driving transistors are to be all field-effect transistor; wherein each switching transistor is connected with the output of each operational amplifier with source terminal; its drain end is connected with the gate terminal of driving transistors; its gate terminal is to be connected with the output of pulse generator; each driving transistors is normal phase input end and each coil that is connected to each operational amplifier with its drain again; its source electrode is to be ground connection, and its gate terminal is the output that is connected to aforementioned pulse generator.
3. the coil driver of a kind of tool power supply tracking and over-voltage protecting function according to claim 2 is characterized in that, wherein the gate terminal of each switching transistor is to see through an inverter to be connected to pulse generator.
4. the coil driver of a kind of tool power supply tracking and over-voltage protecting function according to claim 3 is characterized in that, wherein the gate terminal of each switching transistor is to see through an inverter to be connected to pulse generator.
5. the coil driver of a kind of tool power supply tracking and over-voltage protecting function according to claim 4 is characterized in that, wherein the gate terminal of each driving transistors is to see through the output that a current-limiting resistance is connected to pulse generator.
6. the coil driver of a kind of tool power supply tracking and over-voltage protecting function according to claim 5; it is characterized in that; wherein the drain end of each driving transistors is the anode tap that is connected to a diode respectively; the cathode terminal of each diode is the cathode terminal that is connected to a Zener diode again, and the anode tap of this Zener diode is to be connected to power end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011100591A CN1201475C (en) | 2001-03-28 | 2001-03-28 | Coil driver with power supply tracking and over-voltage protecting functions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011100591A CN1201475C (en) | 2001-03-28 | 2001-03-28 | Coil driver with power supply tracking and over-voltage protecting functions |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1377128A CN1377128A (en) | 2002-10-30 |
| CN1201475C true CN1201475C (en) | 2005-05-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB011100591A Expired - Fee Related CN1201475C (en) | 2001-03-28 | 2001-03-28 | Coil driver with power supply tracking and over-voltage protecting functions |
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| Country | Link |
|---|---|
| CN (1) | CN1201475C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7339402B2 (en) * | 2006-02-13 | 2008-03-04 | Texas Instruments Incorporated | Differential amplifier with over-voltage protection and method |
| CN102013861B (en) * | 2010-09-14 | 2012-12-26 | 成都芯源系统有限公司 | Direct current (DC) brushless motor system and driving method thereof |
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2001
- 2001-03-28 CN CNB011100591A patent/CN1201475C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CN1377128A (en) | 2002-10-30 |
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Granted publication date: 20050511 Termination date: 20170328 |
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