CN202551415U - LED linear current control circuit and LED linear circuit - Google Patents
LED linear current control circuit and LED linear circuit Download PDFInfo
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- CN202551415U CN202551415U CN2012200246277U CN201220024627U CN202551415U CN 202551415 U CN202551415 U CN 202551415U CN 2012200246277 U CN2012200246277 U CN 2012200246277U CN 201220024627 U CN201220024627 U CN 201220024627U CN 202551415 U CN202551415 U CN 202551415U
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Abstract
The utility model discloses an LED linear current control circuit including an LED string, which is formed by the serial connection of at least one LED; an input voltage sampling network for sampling the input voltage of the LED; a comparison and control circuit for acquiring a comparison result by comparing the input voltage of each LED with a reference voltage; and a multiplexer switch which is respectively connected to the LED and changes the conduction impedance of the LED based on the comparison result to control the conduction of part of or all of the LED. The utility model further discloses an LED linear circuit.
Description
Technical field
The utility model relates to a kind of LED linear current control circuit, relates in particular to a kind of linear current control circuit that can regulate LED brightness through change input controllable silicon dimmer cut angular dimension.
Background technology
Fig. 1 is traditional linear constant-current control circuit of LED.The LED lamp is series-connected to the anode of input rectifying bridge 100 among the figure, through one be connected to input rectifying bridge 100 ground ends linear constant-current source 102 set the electric current that flows through LED.The position of LED200 and linear constant-current source 102 can exchange each other.
Because LED lamp string is in series by a lot of LED200, so forward conduction voltage is very high.According to the principle of LED conducting, only when input voltage was higher than LED200 forward conduction voltage, LED lamp string just can be lighted.In the system of mains-supplied, LED lamp string only just can be lighted near input voltage reaches peak value, so the utilance of LED is very low, power factor is not high yet.If reduce the LED lamp quantity of series connection, though can increase the utilance of LED, the power consumption of constant-current control circuit is increased greatly, thereby reduce the efficient of whole drive circuit, increase the temperature rise of drive circuit.If the electric current when increase LED lamp is lighted though can improve the brightness of LED, then need adopt more high-power LED, thereby increase the cost of system, system power dissipation also can increase along with the increase of LED drive current.
The utility model content
In order to overcome the defective that exists in the prior art, the utility model provides a kind of LED linear current control circuit, can light part or all of LED through the size of LED electric current according to actual flow, thereby improves the utilance of LED.
In order to realize above-mentioned utility model purpose, the utility model discloses a kind of LED linear current control circuit, comprising: a LED lamp string, and this LED lamp string is in series by at least one LED; One input voltage sampling network, the input voltage of this LED that is used to sample; One comparison and control circuit, with the input voltage of this each LED respectively with a reference voltage comparison to obtain a comparative result; One multidiameter option switch, this multidiameter option switch connects this LED respectively, and this multidiameter option switch changes its conduction impedance according to this comparative result, with control section or all LED conductings.
Further, this input voltage sampling network comprises at least one current sampling resistor, this current sampling resistor one end ground connection, and the other end is connected with control circuit and this multidiameter option switch with this comparison.
Further, this comparison comprises an operational amplifier with control circuit, and the input anode of this operational amplifier is connected with this reference voltage, and wherein input cathode is connected with this voltage sample network, and output is connected with this multidiameter option switch.This multidiameter option switch comprises a control end, switch input terminal and output switching terminal, and the voltage or the electric current that change this control end are to change the conduction impedance of this switch input terminal and output switching terminal.This control end is connected with the output of this operational amplifier, and this switch input terminal is connected with this LED, and this output switching terminal is connected with input cathode and this input voltage sampling network of this operational amplifier.
Further, this reference voltage is an equal values, perhaps is different value.
The utility model discloses a kind of LED linear circuit simultaneously, comprising: rectifier bridge and LED linear current control circuit, this LED linear current control circuit adopts like each described LED linear current control circuit of preceding text.
Compared with prior art; The utility model compares through sampling LED electric current and reference voltage; The conduction impedance of control multidiameter option switch; Can in the whole cycle, increase the time that LED is lighted gradually not reducing LED quantity or not increasing under the prerequisite of LED electric current, thereby improve the utilance and total output lumen number of LED.So the utility model has improved the efficient of drive circuit, increased the power factor of input power supply, reduced the cost of system.And through changing input controllable silicon dimmer cut angular dimension adjusting LED brightness.In this simultaneously, through the size of control LED electric current, can realize controlling to reduce net side input current harmonics to the adjusting of LED brightness and to net side input current; And the utility model need not detect the variation of input voltage, and variation that just can the self adaptation input voltage realizes LED Current Control and the control of net side input current harmonics.
Description of drawings
Can detail and appendedly graphicly further understood through following utility model about the advantage of the utility model and spirit.
Fig. 1 is traditional linear constant-current control circuit sketch map of LED;
Fig. 2 is the circuit diagram according to the shown LED linear current of the utility model control circuit.
Embodiment
Specify the specific embodiment of the utility model below in conjunction with accompanying drawing.
The linear constant-current control circuit of traditional LED, LED lamp string only just can be lighted near input voltage reaches peak value.
The utility model provides a kind of LED linear current control circuit, when input voltage is low, just can light partial L ED, thereby improves the utilance of LED.In order to realize this utility model purpose, a kind of LED linear current control circuit is characterized in that, comprising: a LED voltage sample network, and the electric current of the LED that is used to sample obtains sampled voltage; One comparison and control circuit are exported a comparative result according to a sampled voltage and a reference voltage that said sampling network obtains; One multidiameter option switch is used for the conduction impedance according to said comparative result control multidiameter option switch, makes part or all of LED conducting, realizes the electric current of control flows through this LED.
The sampled voltage that above-mentioned comparison and control circuit obtain through above-mentioned LED voltage sample network; Relatively control the conduction impedance of above-mentioned multidiameter option switch according to built-in reference voltage; Make LED lamp pearl string to change, light the lamp pearl in the LED lamp pearl string gradually with input voltage.When input voltage, have partial L ED and light; When input voltage is higher, thereby most of or whole LED lights the time that LED is lighted that increases, and improves the utilance and total lumen number of exporting of LED, and can reduce net side input current harmonics, improves power factor, also can realize dimming function simultaneously.
Below will combine Fig. 2 to specify the utility model.Fig. 2 is the enforcement circuit of the shown LED linear current of the utility model control circuit, comprises LED voltage sample network 400, comparison and control circuit 300, multidiameter option switch and LED lamp string LED1 ~ LEDn.Wherein comprise in this voltage sample network 400 and comprise built-in operational amplifier OP1-OPn and reference voltage V in sampling resistor Rcs1-Rcsn, comparison and the control circuit 300
REF1-V
REFn, multidiameter option switch comprises SW1-SWn and LED lamp string LED1 ~ LEDn.
In this execution mode, this LED voltage sample network 400 comprises that three sampling resistor Rcs1, Rcs2, Rcsn are connected respectively to the CS1 of comparison and control circuit 300, CS2 and CSn, is connected with the output OUT1-OUTn of variable connector SW1, SW2, SWn again; The control end CON1-CONn of multidiameter option switch SW1-SWn is connected with operational amplifier OP1-OPn output G1-Gn respectively; The positive pole of operational amplifier OP1-OPn and reference voltage V
REF1-V
REFnBe connected; The negative pole of operational amplifier OP1-OPn is connected respectively with CS1, CS2 and the CSn of control circuit 300 with comparison; The input IN1-INn of multidiameter option switch SW1-SWn is connected respectively to the negative electrode of LED lamp string LED1 ~ LEDn.LED1 ~ LEDn is from beginning to end, and the anode of last LED1 is connected to the anode of rectifier bridge 100.
The LED linear current control circuit that the utility model provided is through voltage sample network 400 obtain the flowing through sampled voltage of LED1 ~ LEDn electric current, and this sampled voltage is the anodal reference voltage V with being connected to operational amplifier OP1-OPn again
REF1-V
REFnOP1-OPn compares and enlarges through operational amplifier; Adjusting is connected to the voltage or the electric current of control end of the multidiameter option switch SW1-SWn of operational amplifier OP1-OPn output G1-Gn; Realize the conduction impedance adjusting of multidiameter option switch SW1-SWn, reach the purpose of control LED lamp string LED1 ~ LEDn electric current.
The LED linear current control circuit that the utility model provided can be lighted the LED of varying number according to different input voltages.The utility model only need be through being provided with different reference voltage V
REF1-V
REFnJust can control the electric current of LED lamp string LED1 ~ LEDn, make electric current I _ LED=V of LED lamp string LED1 ~ LEDn
REFn/ Rcsn.
In the system by mains-supplied, busbar voltage is an AC sine wave.Very low at input voltage; And be not enough to touch when leading to LED lamp pearl string; All multidiameter option switchs are in whole low-resistance conducting states in the utility model; Along with input voltage rises gradually, LED1 lamp pearl string flows through electric current earlier, and operational amplifier OP1 begins the sampled voltage and the reference voltage V of comparison LED electric current
REF1Change the conduction impedance of multidiameter option switch SW1, make electric current I _ LED=V of LED lamp string LED1
REF1/ Rcs1.When input voltage further rises to can touch logical LED2 lamp pearl string the time, because multidiameter option switch SW2 is in the low-resistance conducting state, LED2 lamp pearl is gone here and there the automatic conducting electric current of flowing through, and operational amplifier OP2 begins the sampled voltage and the reference voltage V of comparison LED electric current
REF2Change the conduction impedance of multidiameter option switch SW2, make electric current I _ LED=V of LED lamp string LED2
REF2/ Rcs2.And the like; When input voltage further rises to can touch logical LEDn lamp pearl string the time; Because multidiameter option switch SWn is in the low-resistance conducting state, LEDn lamp pearl is gone here and there the automatic conducting electric current of flowing through, and operational amplifier OPn begins the sampled voltage and the reference voltage V of comparison LED electric current
REFnThe conduction impedance that changes multidiameter option switch SWn makes electric current I _ LED=V of LED lamp string LEDn
REFn/ Rcsn.
When input voltage begins to drop to when being not enough to touch logical LEDn lamp pearl string, LEDn lamp pearl string does not just have electric current to flow through, and multidiameter option switch SWn returns to the low-resistance conducting state, and operational amplifier OP2 begins the sampled voltage and the reference voltage V of comparison LED electric current
REF2Change the conduction impedance of multidiameter option switch SW2, make electric current I _ LED=V of LED lamp string LED2
REF2/ Rcs2.And the like; When input voltage further drops to when being not enough to touch logical LED2 lamp pearl string; Multidiameter option switch SW2 returns to the low-resistance conducting state, and LED2 lamp pearl string does not just have electric current to flow through, and operational amplifier OP1 begins the sampled voltage and the reference voltage V of comparison LED electric current
REF1Change the conduction impedance of multidiameter option switch SW1, make electric current I _ LED=V of LED lamp string LED1
REF1/ Rcs1.When input voltage further drops to when being not enough to touch logical all LED lamp pearls strings, multidiameter option switch SW1-SWn full recovery is to the low-resistance conducting state.
Described reference voltage V REF1-VREFn can be separate, also can be interrelated.When the input voltage rising, LED2 lamp pearl start of string conducting electric current rises so flow through the electric current of multidiameter option switch SW2 gradually, and CS2 voltage also begins to rise.Can set V
REF1Reduce along with the rising of CS2 voltage, make the electric current flow through multidiameter option switch SW1 reduce gradually, thus electric current gradually from multidiameter option switch SW1 level and smooth switch to SW2.And constant basically from the electric current of bus input, reduced the noise of introducing when multidiameter option switch switches.Other multidiameter option switchs also can be taked same control method when beginning conducting and turn-offing, and make the bus input current in the whole cycle, keep constant basically.
Periodic duty according to this, the LED linear current control circuit that the utility model provided can just be lighted partial L ED through control LED electric current; When input voltage is high, then light whole LED.Therefore, the utility model adopts the adaptive segmentation switching technique can in the whole cycle, increase the time that LED is lighted, thereby improves the utilance and total output lumen number of LED, can reduce net side input current harmonics simultaneously, improves power factor.
The preferred embodiment of the just the utility model described in this specification, above embodiment is only in order to the technical scheme of explanation the utility model but not to the restriction of the utility model.All those skilled in the art according to the design of the utility model through the available technical scheme of logical analysis, reasoning, or a limited experiment, all should be within the scope of the utility model.
Claims (7)
1. a LED linear current control circuit is characterized in that, comprising:
One LED lamp string, said LED lamp string is in series by at least one LED;
One input voltage sampling network, the input voltage of the said LED that is used to sample;
One comparison and control circuit, with the input voltage of said each LED respectively with a reference voltage comparison to obtain a comparative result;
One multidiameter option switch, said multidiameter option switch connects said LED respectively, and said multidiameter option switch changes its conduction impedance according to said comparative result, with control section or all LED conductings.
2. LED linear current control circuit as claimed in claim 1; It is characterized in that; Said input voltage sampling network comprises at least one current sampling resistor, said current sampling resistor one end ground connection, and the other end is connected with control circuit and said multidiameter option switch with said comparison.
3. LED linear current control circuit as claimed in claim 1; It is characterized in that; Said comparison comprises an operational amplifier with control circuit; The input anode of said operational amplifier is connected with said reference voltage, and wherein input cathode is connected with said voltage sample network, and output is connected with said multidiameter option switch.
4. LED linear current control circuit as claimed in claim 3; It is characterized in that; Said multidiameter option switch comprises a control end, switch input terminal and output switching terminal, and the voltage or the electric current that change said control end are to change the conduction impedance of said switch input terminal and output switching terminal.
5. LED linear current control circuit as claimed in claim 4; It is characterized in that; Said control end is connected with the output of said operational amplifier; Said switch input terminal is connected with said LED, and said output switching terminal is connected with the input cathode and the said input voltage sampling network of said operational amplifier.
6. LED linear current control circuit as claimed in claim 1 is characterized in that said reference voltage is an equal values, perhaps is different value.
7. LED linear circuit comprises: rectifier bridge and LED linear current control circuit is characterized in that said LED linear current control circuit adopts like each described LED linear current control circuit of claim 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200246277U CN202551415U (en) | 2012-01-19 | 2012-01-19 | LED linear current control circuit and LED linear circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200246277U CN202551415U (en) | 2012-01-19 | 2012-01-19 | LED linear current control circuit and LED linear circuit |
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| CN202551415U true CN202551415U (en) | 2012-11-21 |
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| CN2012200246277U Expired - Lifetime CN202551415U (en) | 2012-01-19 | 2012-01-19 | LED linear current control circuit and LED linear circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102595715A (en) * | 2012-01-19 | 2012-07-18 | 上海晶丰明源半导体有限公司 | Light-emitting diode (LED) linear current control circuit and LED linear circuit |
| CN103260299A (en) * | 2013-01-07 | 2013-08-21 | 美芯晟科技（北京）有限公司 | Multi-branch-circuit linear LED driver and driving method |
| CN103874260A (en) * | 2012-12-07 | 2014-06-18 | 普诚科技股份有限公司 | Lighting system and control method thereof |
| CN103887769A (en) * | 2012-12-20 | 2014-06-25 | 陕西亚成微电子股份有限公司 | Linear high-voltage LED driver protection circuit |
| CN107454711A (en) * | 2014-08-07 | 2017-12-08 | 矽力杰半导体技术(杭州)有限公司 | A kind of multipath LED drive circuit, driving method and LED drive power |
-
2012
- 2012-01-19 CN CN2012200246277U patent/CN202551415U/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102595715A (en) * | 2012-01-19 | 2012-07-18 | 上海晶丰明源半导体有限公司 | Light-emitting diode (LED) linear current control circuit and LED linear circuit |
| CN103874260A (en) * | 2012-12-07 | 2014-06-18 | 普诚科技股份有限公司 | Lighting system and control method thereof |
| CN103887769A (en) * | 2012-12-20 | 2014-06-25 | 陕西亚成微电子股份有限公司 | Linear high-voltage LED driver protection circuit |
| CN103887769B (en) * | 2012-12-20 | 2017-06-06 | 陕西亚成微电子股份有限公司 | Linear low density LED driver protection circuit |
| CN103260299A (en) * | 2013-01-07 | 2013-08-21 | 美芯晟科技（北京）有限公司 | Multi-branch-circuit linear LED driver and driving method |
| CN103260299B (en) * | 2013-01-07 | 2015-12-02 | 美芯晟科技（北京）有限公司 | A kind of Multi-branch-circuitlinear linear LED driver and driving method |
| CN107454711A (en) * | 2014-08-07 | 2017-12-08 | 矽力杰半导体技术(杭州)有限公司 | A kind of multipath LED drive circuit, driving method and LED drive power |
| CN107454711B (en) * | 2014-08-07 | 2019-11-05 | 矽力杰半导体技术(杭州)有限公司 | A kind of multipath LED drive circuit, driving method and LED drive power |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: 5 room 504-511, room 2, Lane 666, Zhang Heng Road, Pudong New Area, China (Shanghai) free trade zone, Shanghai, China () Patentee after: Shanghai semiconducto Limited by Share Ltd Address before: 201204 Shanghai city Pudong New Area in 299 Lane Road, Room 502 No. 6 Patentee before: Shanghai Bright Power Semiconductor Co.,Ltd. |
|
| CP03 | Change of name, title or address | ||
| CX01 | Expiry of patent term |
Granted publication date: 20121121 |
|
| CX01 | Expiry of patent term |