CN206181505U - Be applied to constant voltage current -limiting control circuit of discharge lamp ballast - Google Patents
Be applied to constant voltage current -limiting control circuit of discharge lamp ballast Download PDFInfo
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- CN206181505U CN206181505U CN201621156634.7U CN201621156634U CN206181505U CN 206181505 U CN206181505 U CN 206181505U CN 201621156634 U CN201621156634 U CN 201621156634U CN 206181505 U CN206181505 U CN 206181505U
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Abstract
The utility model discloses a be applied to constant voltage current -limiting control circuit of discharge lamp ballast, does the discharge lamp ballast include DC DC transfer circuit, controller, switch tube drive circuit and output voltage sampling circuit, DC the DC transfer circuit has an output state and the 2nd output state. Constant voltage current -limiting control circuit includes current sampling circuit, differential amplification circuit, clamp circuit, bleeder circuit and comparison circuit, current sampling circuit is connected with the second end of switch tube, differential amplification circuit's first input end is connected in voltage sampling circuit's output, and reference voltage is connected to the second input, and the output is connected with clamp circuit. Bleeder circuit's input and clamp circuit are connected. Comparison circuit's first input end and current sampling circuit are connected, and the second input is connected with bleeder circuit, and the output is connected with controller and switch tube drive circuit's input. The utility model discloses can realize accurate constant voltage control and current -limiting control on the basis of low cost.
Description
Technical field
This utility model is related to gas discharge lamp ballast.
Background technology
Gas-discharge lamp is increasingly being applied to automotive lighting, according to the characteristic of gas discharge, needs exploitation special
Ballast.For gas breakdown, ballast needs to produce the two poles of the earth that constant high pressure acts on gas-discharge lamp, and in ballast
In the course of work, setting current-limiting protection circuit is needed to prevent magneticss saturation, protection switch pipe.
In current constant pressure solution, some constant pressure solutions are to coordinate to realize perseverance using MCU and comparator
Pressure, MCU provides control pwm signal to switching tube, and the output voltage signal of comparator feedback DC-DC conversion circuit is to MCU；Than
Output voltage is detected more than after target output voltage, MCU stops output pwm control signal, and current path to be output is arrived compared with device
MCU exports again pwm control signal again after lower than target output voltage.The advantage of this scheme is that device used is few, is lacked
Point is constant pressure low precision, and continuous several big space rates are occurred in the course of work, then continuously turns off several cycles, causes output electricity
Pressure fluctuation range is than larger.Other constant pressure solutions carry out constant pressure using special DC/DC control chips, and Isobarically Control is very smart
Standard, output voltage only has the switching harmonics of very little, but the cost of DC/DC control chips is higher.
In current current limliting scheme, some current limliting schemes do not have the electric current of limit switch pipe, cause magneticss possible
Meeting saturation, the life-span of switching tube can be affected, or even directly break down；Other current limliting schemes utilize the conducting resistance of switching tube
Do current sampling resistor, then coordinate comparator to work, carry out the electric current of limit switch pipe, due to the conducting resistance of switching tube it is driven
Voltage, temperature impact it is very big, this scheme current limliting can be very inaccurate.
The content of the invention
Technical problem to be solved in the utility model is to provide one kind on the basis of low cost to be integrated with accurate perseverance
The constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast of voltage-controlled system and Current limited Control.
To solve above-mentioned technical problem, technical solution adopted in the utility model is：
The constant voltage and current limiting control circuit of gas discharge lamp ballast is applied to, gas discharge lamp ballast becomes including DC-DC
Change circuit, controller, switch tube driving circuit and output voltage sampling circuit；DC-DC conversion circuit includes transformator and switch
Pipe, one end of the primary coil of transformator is connected with the first end of switching tube；The outfan and switch tube driving circuit of controller
Input connection, the outfan of switch tube driving circuit is connected with the control end of switching tube；Output voltage sampling circuit it is defeated
Enter end to be connected with the outfan of the DC-DC conversion circuit, for sampling the output voltage of DC-DC conversion circuit；DC-
DC translation circuits have the first output state and the second output state, and DC-DC conversion circuit is in gas-discharge lamp in startup rank
The first output state is in during section, the second output state is in after gas-discharge lamp punctures；Wherein, constant voltage and current limiting control circuit
Including current sampling circuit, differential amplifier circuit, clamp circuit, bleeder circuit and comparison circuit；Current sampling circuit and switch
The second end connection of pipe, for the voltage sampled with the current in proportion for flowing through switching tube；First input of differential amplifier circuit
End is connected to the outfan of voltage sampling circuit, and the second input of differential amplifier circuit connects the ginseng corresponding to predetermined constant pressure value
Voltage is examined, the outfan of differential amplifier circuit is connected with clamp circuit；The input of bleeder circuit is connected with the clamp circuit；
Clamp circuit is used to be disconnected when DC-DC conversion circuit is in the first output state, in DC-DC conversion circuit in the second output
The output voltage of differential amplifier circuit is clamped to predetermined magnitude of voltage during state；The first input end of comparison circuit is adopted with electric current
The outfan connection of sample circuit, the second input of comparison circuit is connected with the outfan of bleeder circuit, the output of comparison circuit
End is connected respectively with the input of controller and the input of switch tube driving circuit.
After above-mentioned technical proposal, this utility model at least has advantages below and feature：
1st, it is defeated in first in DC-DC conversion circuit according to the constant voltage and current limiting control circuit of the embodiment of this utility model one
A closed-loop control system is defined when doing well, can Cycle by Cycle ground current limliting, Cycle by Cycle ground controlling switch pipe dutycycle,
Make DC-DC conversion circuit produce accurately output voltage, while reach the effect of constant pressure, also switch tube serves current limliting guarantor
The effect of shield；And when DC-DC conversion circuit is in the second output state, according to the constant voltage and current limiting of the embodiment of this utility model one
Control circuit is changed into current-limiting protection circuit, can accurately limit the electric current for flowing through switching tube, and switch tube plays good guarantor
Shield, and prevent the magneticss of DC-DC conversion circuit from reaching saturation；
2nd, according to the constant voltage and current limiting control circuit of the embodiment of this utility model one simultaneously output control signal to controller and
Switch tube driving circuit, controllable switch tube drive circuit is directly turned on and off switching tube, and realizes controller to feedback
The latch of control signal.
Description of the drawings
Fig. 1 shows the constant voltage and current limiting control for being applied to gas discharge lamp ballast according to the embodiment of this utility model one
The circuit theory diagrams of circuit.
Specific embodiment
Below in conjunction with the accompanying drawings this utility model is described in detail with specific embodiment.
Fig. 1 shows the constant voltage and current limiting control for being applied to gas discharge lamp ballast according to the embodiment of this utility model one
The circuit theory diagrams of circuit.Fig. 1 is referred to, gas discharge lamp ballast includes DC-DC conversion circuit 1, controller 2, switching tube
Drive circuit 3 and output voltage sampling circuit 4.
DC-DC conversion circuit 1 includes transformator T, switching tube Q1 and is filtered by the rectification that diode D1 and electric capacity Co are constituted
Wave circuit.One end of one end of the primary coil L1 of transformator T and the secondary coil L2 of transformator T is respectively with switching tube Q1's
First end connects, and the other end of the primary coil L1 of transformator T is connected with DC input voitage Vin.The secondary coil of transformator T
The other end of L2 is connected with the input of current rectifying and wave filtering circuit, and the outfan of current rectifying and wave filtering circuit is connected with load RL.Rectification is filtered
The output voltage of wave circuit is the output voltage Vo of DC-DC conversion circuit 1.
The outfan of controller 2 is connected with the input of switch tube driving circuit 3, the outfan of switch tube driving circuit 3
It is connected with the control end of switching tube Q1.The input of output voltage sampling circuit 4 is connected with the outfan of DC-DC conversion circuit 1,
For sampling to the output voltage of DC-DC conversion circuit 1.DC-DC conversion circuit 1 is defeated with the first output state and second
Do well, when gas-discharge lamp is in startup stage, DC-DC conversion circuit 1 is in the first output state, now DC-DC conversion
The high pressure of a few hectovolts of circuit output（Such as 400V）, DC-DC conversion circuit 1 is in the second output shape after gas-discharge lamp punctures
State, the output voltage Vo of DC-DC conversion circuit 1 is down to tens volts.
Included according to the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast of the embodiment of this utility model one
Current sampling circuit 5, differential amplifier circuit 6, clamp circuit 7, bleeder circuit 8 and comparison circuit 9.
Current sampling circuit 5 is connected with second end of switching tube Q1, for sample with flow through the electric current of switching tube Q1 into than
The voltage of example.
The first input end of differential amplifier circuit 6 is connected to the outfan of voltage sampling circuit 4, differential amplifier circuit 6
Second input connects the reference voltage Vset corresponding to predetermined constant pressure value, outfan and the clamp circuit 7 of differential amplifier circuit 6
Connection.Above-mentioned constant pressure value is, for example, 400V.
The input of bleeder circuit 8 is connected with clamp circuit 7.Clamp circuit 7 is used in DC-DC conversion circuit 1 in the
Disconnect during one output state, when DC-DC conversion circuit 1 is in the second output state by the output voltage of differential amplifier circuit 6
Clamp to predetermined magnitude of voltage.
The first input end of comparison circuit 9 is connected with the outfan of current sampling circuit 5, the second input of comparison circuit 9
End is connected with the outfan of bleeder circuit 8, and the outfan of comparison circuit 9 drives respectively with the input and switching tube of controller 2
The input connection of circuit 3, controller 2 is used for output pwm signal to switch tube driving circuit 3, and controller 2 is also to relatively more electric
The output signal on road 9 is latched.Because switch tube driving circuit 3 does not have " memory " function, if the output letter of comparison circuit 9
Number only export to switch tube driving circuit 3, concussion can be caused, switching tube Q1 occur repeatedly open-minded in a switch periods
With the situation of shut-off.
In the present embodiment, transformator T is coupling inductance booster transformer.Switching tube Q1 is NMOS tube；NMOS tube Q1
Grid, drain electrode and source electrode respectively constitute control end, first end and second end of switching tube Q1.Current sampling circuit 5 is adopted by electric current
Sample resistance Rs is constituted, and one end of current sampling resistor Rs is connected with the source electrode of NMOS tube Q1, other end ground connection.Controller 2 is
MCU.Chip that switch tube driving circuit 3 is produced by TI companies, model UCC27517 is constituted.Output voltage sampling circuit 4
For resistor voltage divider circuit, the resistor voltage divider circuit is made up of resistance Rf1, the Rf2 being serially connected.Differential amplifier circuit 6 is by amplifier
U4, resistance R1, resistance R2 compositions.Clamp circuit 7 is made up of clamp diode D2.The negative pole and reference voltage of clamp diode D2
Connection, the positive pole of clamp diode D2 is connected respectively with the outfan of differential amplifier circuit 6 and 8 inputs of bleeder circuit；Pincers
Position diode D2 reverse-biased cut-offs when DC-DC conversion circuit 1 is in the first output state, in DC-DC conversion circuit 1 second is in
Positively biased conducting during output state.The reference voltage of clamp diode D2 is not limited to the 3.3V shown in Fig. 1, as long as stable patrols
Volume level can, such as 5V.Bleeder circuit 8 is resistor voltage divider circuit, and the resistor voltage divider circuit is by the resistance R4 being serially connected
With resistance R5 compositions.Comparison circuit 9 is made up of amplifier comparison circuit U3.
Preferably, constant voltage and current limiting control circuit includes the first current-limiting circuit 10a, flows from differential amplifier circuit 6 for limiting
The electric current for going out；The input of the first current-limiting circuit 10a is connected with the outfan of differential amplifier circuit 6, the first current-limiting circuit 10a
Outfan is connected with clamp circuit 7.
Preferably, constant voltage and current limiting control circuit includes the second current-limiting circuit 10b, for limiting what is flowed out from comparison circuit 9
Electric current；The input of the second current-limiting circuit 10b is connected with the outfan of comparison circuit 9, the outfan point of the second current-limiting circuit 10b
It is not connected with the input of switch tube driving circuit 3 and the input of controller 2.
In the present embodiment, the first current-limiting circuit 10a and the second current-limiting circuit 10b are respectively by current-limiting resistance R3 and current limliting electricity
Resistance R4 is constituted.
When gas-discharge lamp is in startup stage, the height for producing several hectovolts is needed in the outfan of DC-DC conversion circuit 1
Pressure, and to reach certain precision, i.e. the output of DC-DC conversion circuit 1 is in the first output state.
Controller 2 produces pwm signal to switch tube driving circuit 3, and switch tube driving circuit 3 is exported according to controller 2
Pwm signal and the control signal of the output of comparison circuit 9, carry out the turn-on and turn-off of controlling switch pipe Q1.Wherein, comparison circuit 9 is defeated
The control signal for going out and the relation that the pwm signal of the output of controller 2 is logical AND, as long as wherein any one signal command switch
The on-off switching tube of tube drive circuit 3, switch tube driving circuit 3 all can be performed switching tube Q1 shut-offs.
Output voltage sampling circuit 4 exports the output voltage Vo of the DC-DC conversion circuit 1 for collecting after partial pressure should
Differential amplifier circuit 6, differential amplifier circuit 6 by the output voltage of given reference voltage Vset and output voltage sampling circuit 4 it
Difference is exported after being amplified with certain gain.The output voltage of differential amplifier circuit 6 obtains Vf through current-limiting resistance R3.Vf is less than pincers
The reference voltage 3.3V of position diode D2, the reverse-biased cut-offs of clamp diode D2.Vf forms ratio after the partial pressure of bleeder circuit 8
Compared with reference voltage V ref of circuit 9.In the present embodiment, the output voltage Vo of reference voltage V ref and DC-DC conversion circuit 1 into
The output voltage Vo of inversely proportional relation, i.e. DC-DC conversion circuit 1 is bigger, and reference voltage V ref is less, and vice versa.Relatively
The voltage signal that the benchmark voltage Vref of circuit 9 and current sampling resistor Rs feed back, produces output signal, output signal
Through current-limiting resistance R6, the input of controller 2 and switch tube driving circuit 3 is given to, so as to the conducting of controllable switch pipe Q1
Time.When Vref reduces, the ON time for also implying that switching tube Q1 is reduced, so that the output of DC-DC conversion circuit 1
Voltage Vo is reduced, and when Vref increases, the ON time of switching tube Q1 increases under the control of comparison circuit, so that DC-DC
The output voltage Vo of translation circuit 1 increases.The closed loop control to output voltage Vo is material is thus formed, and Cycle by Cycle ground is limited
Flow through the electric current of switching tube Q1.The desired value of Vo is set by given reference voltage Vset.Because be Cycle by Cycle carry out duty
Than control, so the precision of target voltage is very high, only switching harmonics voltage.
After gas-discharge lamp is breakdown, the output voltage Vo of DC-DC conversion circuit 1 is down to tens volts by several hectovolts, DC-DC
The output of translation circuit 1 is in the second output state.Amplifier U4 forward direction saturation, it is left in 4.0V that Vf is clamped diode D2 clamps
It is right.Vf forms reference voltage V ref of comparison circuit 9 after the partial pressure of bleeder circuit 8.Reference voltage V ref, current sample
Resistance Rs and comparison circuit 9 form switch tube Q1 more accurately current-limiting circuit.
Claims (8)
1. the constant voltage and current limiting control circuit of gas discharge lamp ballast is applied to, and the gas discharge lamp ballast includes DC-DC
Translation circuit, controller, switch tube driving circuit and output voltage sampling circuit；The DC-DC conversion circuit includes transformator
And switching tube, one end of the primary coil of the transformator is connected with the first end of the switching tube；The output of the controller
End is connected with the input of the switch tube driving circuit, the control of the outfan of the switch tube driving circuit and the switching tube
End connection processed；The input of the output voltage sampling circuit is connected with the outfan of the DC-DC conversion circuit, for right
The output voltage of DC-DC conversion circuit is sampled；The DC-DC conversion circuit has the first output state and the second output shape
State, the DC-DC conversion circuit is in the first output state when gas-discharge lamp is in startup stage, hits in gas-discharge lamp
The second output state is in after wearing；Characterized in that, the constant voltage and current limiting control circuit includes current sampling circuit, differential amplification
Circuit, clamp circuit, bleeder circuit and comparison circuit；
The current sampling circuit is connected with the second end of the switching tube, for sample with flow through the electric current of the switching tube into
The voltage of ratio；
The first input end of the differential amplifier circuit is connected to the outfan of the voltage sampling circuit, the differential amplification electricity
Second input on road connects the reference voltage corresponding to predetermined constant pressure value, the outfan of the differential amplifier circuit and the pincers
Position circuit connection；
The input of the bleeder circuit is connected with the clamp circuit；The clamp circuit is used in DC-DC conversion electricity
Road disconnects when being in the first output state, when the DC-DC conversion circuit is in the second output state by the differential amplification
The output voltage of circuit is clamped to predetermined magnitude of voltage；
The first input end of the comparison circuit is connected with the outfan of the current sampling circuit, and the second of the comparison circuit
Input is connected with the outfan of the bleeder circuit, the outfan of the comparison circuit respectively with the input of the controller
Connect with the input of the switch tube driving circuit.
2. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 1, it is characterised in that
The clamp circuit is made up of clamp diode；The negative pole of the clamp diode is connected with reference voltage, two poles of the clamp
The positive pole of pipe is connected respectively with the outfan of the differential amplifier circuit and the input of the bleeder circuit；Described clamp two
Pole pipe reverse-biased cut-off when the DC-DC conversion circuit is in the first output state, in the DC-DC conversion circuit second is in
Positively biased conducting during output state.
3. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 1 and 2, its feature exists
In the constant voltage and current limiting control circuit includes the first current-limiting circuit；The input of first current-limiting circuit is put with the difference
The outfan connection of big circuit, the outfan of first current-limiting circuit is connected with the clamp circuit.
4. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 3, it is characterised in that
The constant voltage and current limiting control circuit includes the second current-limiting circuit；The input of second current-limiting circuit and the comparison circuit
Outfan connects, the outfan of second current-limiting circuit input respectively with the switch tube driving circuit and the control
The input connection of device.
5. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 4, it is characterised in that
Described the first current-limiting circuit and the second current-limiting circuit is made up of respectively current-limiting resistance.
6. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 1, it is characterised in that
The switching tube is NMOS tube；The grid of the NMOS tube, drain electrode and source electrode respectively constitute the control end of the switching tube, first
End and the second end；The current sampling circuit is made up of current sampling resistor, one end of the current sampling resistor with it is described
The source electrode connection of NMOS tube, other end ground connection.
7. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 1, it is characterised in that
Described controller is MCU.
8. the constant voltage and current limiting control circuit for being applied to gas discharge lamp ballast according to claim 1, it is characterised in that
Described transformator is coupling inductance booster transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621156634.7U CN206181505U (en) | 2016-10-31 | 2016-10-31 | Be applied to constant voltage current -limiting control circuit of discharge lamp ballast |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621156634.7U CN206181505U (en) | 2016-10-31 | 2016-10-31 | Be applied to constant voltage current -limiting control circuit of discharge lamp ballast |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206181505U true CN206181505U (en) | 2017-05-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621156634.7U Active CN206181505U (en) | 2016-10-31 | 2016-10-31 | Be applied to constant voltage current -limiting control circuit of discharge lamp ballast |
Country Status (1)
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| CN (1) | CN206181505U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106385755A (en) * | 2016-10-31 | 2017-02-08 | 科博达技术有限公司 | Constant voltage and current limiting control circuit applied to gas discharge lamp ballast |
-
2016
- 2016-10-31 CN CN201621156634.7U patent/CN206181505U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106385755A (en) * | 2016-10-31 | 2017-02-08 | 科博达技术有限公司 | Constant voltage and current limiting control circuit applied to gas discharge lamp ballast |
| CN106385755B (en) * | 2016-10-31 | 2018-10-02 | 科博达技术股份有限公司 | Constant voltage and current limiting control circuit applied to gas discharge lamp ballast |
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| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 201203 Shanghai city Zuchongzhi road Pudong New Area Zhangjiang hi tech Park No. 2388 Patentee after: Koboda technology, Limited by Share Ltd Address before: 201203 Shanghai city Zuchongzhi road Pudong New Area Zhangjiang hi tech Park No. 2388 Patentee before: Keboda Technology Corp. |
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| CP01 | Change in the name or title of a patent holder |