CN104578779A - Hysteresis-current control circuit - Google Patents
Hysteresis-current control circuit Download PDFInfo
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- CN104578779A CN104578779A CN201310505415.XA CN201310505415A CN104578779A CN 104578779 A CN104578779 A CN 104578779A CN 201310505415 A CN201310505415 A CN 201310505415A CN 104578779 A CN104578779 A CN 104578779A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/157—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with digital control
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention relates to a hysteresis-current control circuit. The conventional constant current system is improved, and a control circuit of the constant current system is redesigned so as to achieve a better current control effect. A current detection and hysteresis voltage comparison module is additionally arranged to drive a power tube, and the performance of a current-controlled loop in a power supply management chip is improved, so that the current-controlled loop is faster and more accurate. The performance of a power supply converting system is improved, and a high-current working chip circuit is protected well. The circuit is easily integrated, and the cost of chips and a system is not increased.
Description
Technical field
The invention belongs to integrated circuit fields, be specifically related to the constant-current control device in DC-DC driving chip.
Background technology
In recent years, by the guiding of the concepts such as green, environmental protection, low-carbon (LC), the power supply conversion efficiency of consumer electronics product is day by day subject to people and pays close attention to, and this has higher requirement to the power management chip in this electronic product.High-performance power management chip provides constant voltage or electric current, need voltage or current controlled circuit, and the quality of this two types control circuit structure directly determines the height of system power supply conversion efficiency.
Summary of the invention
The technical problem to be solved in the present invention is: provide a kind of hysteresis current control circuit, improves the performance of current controlled circuit in power management chip.
The present invention for solving the problems of the technologies described above taked technical scheme is: a kind of hysteresis current control circuit, comprise one with the inductance of load in series, in parallel with a voltage stabilizing diode after load in series inductance, the output terminal of voltage stabilizing diode is connected with power supply, the input end of voltage stabilizing diode connects the source electrode of a NMOS power tube M4, the grounded drain of NMOS power tube M4, grid is controlled by control module, it is characterized in that: described control module is connected to form in turn by current detection module, stagnant loop voltag comparison module and a buffer module;
Described current detection module comprises 2 test sides and 1 output terminal, two test sides are the two ends detecting resistance Rsense, detect resistance Rsense series connection access load current path, the current value of load is converted to equal proportion magnitude of voltage and exports to described stagnant loop voltag comparison module by output terminal by current detection module;
Described stagnant loop voltag comparison module comprises 3 input ends and an output terminal, wherein first input end is connected with the output terminal of described current detection module, second input end and the 3rd input end high input voltage reference value Vr1 and low reference voltage value Vr2 respectively, the magnitude of voltage that current detection module exports by stagnant loop voltag comparison module compares with high reference voltage value Vr1 and low reference voltage value Vr2 respectively and processes and export control level to described buffer module; Wherein Vr1>Vr2; High reference voltage value Vr1, low reference voltage value Vr2 can be provided by reference circuit, and the present invention does not relate to reference circuit;
Described buffer module is that its input end is connected with the output terminal of described stagnant loop voltag comparison module, and output terminal is connected with the grid of described NMOS power tube M4 for NMOS power tube M4 provides the impact damper of driving.
By such scheme, described current detection module also comprises the first gain resistor Rg1, the second gain resistor Rg2, error amplifier EA and the first PMOS M1; The high-end connection of first gain resistor Rg1 one end and described detection resistance Rsense pressure drop, the negative input end of other end error originated from input operational amplifier EA; The positive input terminal of the low side error originated from input operational amplifier EA of described detection resistance Rsense pressure drop; The negative input end of error amplifier EA is also connected with the source electrode of the first PMOS M1, and the output terminal of error amplifier EA is connected with the grid of the first PMOS M1; The drain electrode of the first PMOS M1 is through the second gain resistor Rg2 ground connection; The drain electrode of the first PMOS M1 is the output terminal of described current detection module.
By such scheme, described stagnant loop voltag comparison module comprises comparer Comp, the first phase inverter INV1, the second phase inverter INV2, the first NMOS tube M2 and the second NMOS tube M3; The negative input end of comparer Comp is the first input end of described stagnant loop voltag comparison module, and the source electrode of the first NMOS tube M2 is the second input end, and the source electrode of the second NMOS tube M3 is the 3rd input end; The positive input terminal of comparer Comp is connected with the drain electrode of the first NMOS tube M2 and the second NMOS tube M3 respectively; The output terminal of comparer Comp is divided into two-way, and a road is connected with the grid of the first NMOS tube M2, and another road is connected with the input end of the first phase inverter INV1; The output terminal of the first phase inverter INV1 is divided into two-way, and a road is connected with the grid of the second NMOS tube M3, and another road is connected with the input end of the second phase inverter INV2; The output terminal of the second reverser is the output terminal of described stagnant loop voltag comparison module.
Principle of work of the present invention is: improve existing constant-current system, redesigns the control circuit of constant-current system, to reach better Current Control effect.
Beneficial effect of the present invention is:
1, driving power pipe is carried out by increase current detecting and stagnant loop voltag comparison module, improve the performance of current controlled circuit in power management chip, make current controlled circuit sooner, more accurate, improve the performance of power conversion system, the chip circuit of better protection big current work simultaneously;
2, circuit of the present invention is easy to integrated, does not increase chip and system cost.
Accompanying drawing explanation
Fig. 1 is constant-current system schematic diagram
Fig. 2 is the circuit theory diagrams of one embodiment of the invention
Embodiment
Figure 1 shows that a DC-DC voltage-dropping type constant current driving system, comprise an inductance L 1 of connecting with load LOAD, in parallel with a voltage stabilizing diode ZD after load in series inductance L 1, the output terminal of voltage stabilizing diode ZD is connected with power supply Vin, the input end of voltage stabilizing diode ZD connects the source electrode of a NMOS power tube M4, the grounded drain of NMOS power tube M4, grid is controlled by control module, the key of system is the control circuit Control Unit how switching frequency of regulating power pipe M4 and dutycycle, thus the constant current hold on proof load LOAD.
Fig. 2 is the circuit theory diagrams of one embodiment of the invention, in the present invention, the control module in Fig. 1 is divided into current detection module, stagnant loop voltag comparison module and buffer module three part.
Described current detection module comprises 2 test sides and 1 output terminal, two test sides are the two ends detecting resistance Rsense, detect resistance Rsense series connection access load current path, current detection module also comprises the first gain resistor Rg1, the second gain resistor Rg2, error amplifier EA and the first PMOS M1; The high-end connection of first gain resistor Rg1 one end and described detection resistance Rsense pressure drop, the negative input end of other end error originated from input operational amplifier EA; The positive input terminal of the low side error originated from input operational amplifier EA of described detection resistance Rsense pressure drop; The negative input end of error amplifier EA is also connected with the source electrode of the first PMOS M1, and the output terminal of error amplifier EA is connected with the grid of the first PMOS M1; The drain electrode of the first PMOS M1 is through the second gain resistor Rg2 ground connection; The drain electrode of the first PMOS M1 is the output terminal of described current detection module.The current value of load is converted to equal proportion magnitude of voltage and exports to described stagnant loop voltag comparison module by output terminal by current detection module.
Described stagnant loop voltag comparison module comprises 3 input ends and an output terminal, wherein first input end is connected with the output terminal of described current detection module, second input end and the 3rd input end high input voltage reference value Vr1 and low reference voltage value Vr2 respectively, the magnitude of voltage that current detection module exports by stagnant loop voltag comparison module compares with high reference voltage value Vr1 and low reference voltage value Vr2 respectively and processes and export control level to described buffer module; Wherein Vr1>Vr2; High reference voltage value Vr1, low reference voltage value Vr2 can be provided by reference circuit, and the present invention does not relate to reference circuit.
Described stagnant loop voltag comparison module comprises comparer Comp, the first phase inverter INV1, the second phase inverter INV2, the first NMOS tube M2 and the second NMOS tube M3; The negative input end of comparer Comp is the first input end of described stagnant loop voltag comparison module, and the source electrode of the first NMOS tube M2 is the second input end, and the source electrode of the second NMOS tube M3 is the 3rd input end; The positive input terminal of comparer Comp is connected with the drain electrode of the first NMOS tube M2 and the second NMOS tube M3 respectively; The output terminal of comparer Comp is divided into two-way, and a road is connected with the grid of the first NMOS tube M2, and another road is connected with the input end of the first phase inverter INV1; The output terminal of the first phase inverter INV1 is divided into two-way, and a road is connected with the grid of the second NMOS tube M3, and another road is connected with the input end of the second phase inverter INV2; The output terminal of the second reverser is the output terminal of described stagnant loop voltag comparison module.
Described buffer module is that its input end is connected with the output terminal of described stagnant loop voltag comparison module, and output terminal is connected with the grid of described NMOS power tube M4 for NMOS power tube M4 provides the impact damper of driving.
Current detection module principle: detect resistance Rsense series connection access load LOAD current path, load current produces voltage drop thereon, the high-end negative input end being put on error operational amplifier EA by gain resistor Rg1 of this pressure drop, low side puts on positive input terminal, because whole detection electricity is a degeneration factor, when load current increases, the lower terminal voltage detecting resistance Rsense reduces, the positive input terminal of error operational amplifier EA is in order to maintain equal with negative input end voltage (Vea+=Vea-), certainly will to control electric current increase (Irg1=(Vin-Vea-)/Rg1) that PMOS M1 makes to flow through gain resistor Rg1, this electric current produces a voltage (Vso=Rg2*Irg1) again on gain resistor Rg2, following equation is then had to set up:
Vso＝Rg2／Rg1*(Vin-Vea-)＝Rg2／Rg1*(Vin-Vea+)＝Rg2／Rg1*IL／Rsense(1)，
Load current value is converted to equal proportion magnitude of voltage and processes for subsequent conditioning circuit by this testing circuit.
Stagnant loop voltag comparison module has two duties:
State one: when Vso is lower than Vr2, comparer exports high level, and M2 opens, and M3 closes, and the positive terminal voltage of comparer equals Vr1, and the final signal exported exports high level driving power pipe M4 through buffer module Buffer and opens.
State two: when Vso is higher than Vr1, comparer export point is put down, and M2 closes, and M3 opens, and the positive terminal voltage of comparer equals Vr2, and the final signal exported is closed through buffer module Buffer output low level driving power pipe M4.
Two states is changed mutually, can realize stagnant loop voltag comparing function.
Buffer module function: this module provides driving to power tube M4, because power tube is capacity load, so the employing driving circuit that amplification phase inverter enough becomes step by step just can realize the function of this module.
Integrated circuit principle of work: system powers on for the first time, load current IL is zero, and it is zero that current detection module exports Vso, and stagnant loop voltag comparison module gets the hang of one, and power tube M4 opens, and now load current starts to increase, and inductance L 1 starts storage power.When load current reaches a certain high level, be set to IH, current detection module exports Vso higher than Vr1, and stagnant loop voltag comparison module gets the hang of two, and power tube M4 closes, and inductance starts to provide electric current as power supply to load, and load current starts to reduce.Load current reaches a certain low value, is set to IL, and current detection module exports Vso lower than Vr2, and stagnant loop voltag comparison module gets the hang of again one, and power tube M4 reopens, and two states so moves in circles, and can realize hysteretic loop current control.Can be obtained by formula (1): IL=Vso/Rsense*Rg1/Rg2;
Maximum current: Imax=Vr1/Rsense*Rg1/Rg2;
Minimum current: Imin=Vr2/Rsense*Rg1/Rg2;
Overall average electric current can be determined:
Iaverage＝(Imax+Imin)／2
＝(Vr1／Rsense*Rg1／Rg2+Vr2／Rsense*Rg1／Rg2)／2
＝0.5*Rg1／Rg2*(Vr1+Vr2)／Rsense。
Claims (2)
1. a hysteresis current control circuit, comprise one with the inductance of load in series, in parallel with a voltage stabilizing diode after load in series inductance, the output terminal of voltage stabilizing diode is connected with power supply, the input end of voltage stabilizing diode connects the source electrode of a NMOS power tube M4, the grounded drain of NMOS power tube M4, grid is controlled by control module, it is characterized in that: described control module is connected to form in turn by current detection module, stagnant loop voltag comparison module and a buffer module;
Described current detection module comprises 2 test sides and 1 output terminal, two test sides are the two ends detecting resistance Rsense, detect resistance Rsense series connection access load current path, the current value of load is converted to equal proportion magnitude of voltage and exports to described stagnant loop voltag comparison module by output terminal by current detection module;
Described stagnant loop voltag comparison module comprises 3 input ends and an output terminal, wherein first input end is connected with the output terminal of described current detection module, second input end and the 3rd input end high input voltage reference value Vr1 and low reference voltage value Vr2 respectively, the magnitude of voltage that current detection module exports by stagnant loop voltag comparison module compares with high reference voltage value Vr1 and low reference voltage value Vr2 respectively and processes and export control level to described buffer module;
Described buffer module is that its input end is connected with the output terminal of described stagnant loop voltag comparison module, and output terminal is connected with the grid of described NMOS power tube M4 for NMOS power tube M4 provides the impact damper of driving.
2. hysteresis current control circuit according to claim 1, is characterized in that: described current detection module also comprises the first gain resistor Rg1, the second gain resistor Rg2, error amplifier EA and the first PMOS M1; The high-end connection of first gain resistor Rg1 one end and described detection resistance Rsense pressure drop, the negative input end of other end error originated from input operational amplifier EA; The positive input terminal of the low side error originated from input operational amplifier EA of described detection resistance Rsense pressure drop; The negative input end of error amplifier EA is also connected with the source electrode of the first PMOS M1, and the output terminal of error amplifier EA is connected with the grid of the first PMOS M1; The drain electrode of the first PMOS M1 is through the second gain resistor Rg2 ground connection; The drain electrode of the first PMOS M1 is the output terminal of described current detection module.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310505415.XA CN104578779A (en) | 2013-10-23 | 2013-10-23 | Hysteresis-current control circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310505415.XA CN104578779A (en) | 2013-10-23 | 2013-10-23 | Hysteresis-current control circuit |
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| CN104578779A true CN104578779A (en) | 2015-04-29 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107803349A (en) * | 2017-11-27 | 2018-03-16 | 安徽文尧智能光电科技有限公司 | A kind of PWM adjusting control circuits of corn color selector |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107803349A (en) * | 2017-11-27 | 2018-03-16 | 安徽文尧智能光电科技有限公司 | A kind of PWM adjusting control circuits of corn color selector |
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Application publication date: 20150429 |