CN205179420U - LCD TV LED drive circuit - Google Patents
LCD TV LED drive circuit Download PDFInfo
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- CN205179420U CN205179420U CN201521032864.8U CN201521032864U CN205179420U CN 205179420 U CN205179420 U CN 205179420U CN 201521032864 U CN201521032864 U CN 201521032864U CN 205179420 U CN205179420 U CN 205179420U
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Abstract
The utility model discloses a LCD TV LED drive circuit, including the AC -DC converter, the AC -DC converter includes the supplementary voltage output winding of low voltage output winding and LED, the output of low voltage output winding is used for the power supply voltage for the mainboard power supply, still includes DC -DC boost circuit, boost circuit's input with the voltage output end of low voltage output winding is connected, boost circuit's output with the ground end of the supplementary voltage output winding of LED is connected, the voltage output end of the supplementary voltage output winding of LED is connected with LCD TV LED's power input end. The utility model discloses a LCD TV LED drive circuit, through stepping up the lower DC voltage of voltage output and superposeing with the DC voltage of the supplementary voltage output winding of LED output, voltage after the stack is as LED's driving voltage, ingenious utilization the worth lower DC voltage of pressure of low voltage output winding output, do not have high pressure resistant requirement to its electron device, can reduce cost.
Description
Technical field
The utility model relates to a kind of drive circuit, specifically, relates to a kind of liquid crystal television LED drive circuit.
Background technology
In current LED liquid crystal television industry, cost pressure is larger, the LED lamp bar of small-medium size LCD TV many employings single channel, two-way, for above this framework, current television manufacturer adopts the type of drive of two independent AC-DC converter usually, one of them is for driving LED, and another one is used for for main board power supply.Another type of drive is an employing AC-DC converter, adopt during an AC-DC converter and need on this converter, increase a boost voltage output, and then an increase dc-dc carrys out driving LED on the basis of boost voltage.
For the framework of an AC-DC converter, the dc-dc increased below is often because the problem that power is large, output voltage is high of LED lamp bar causes the cost compare of this DC-DC high.The reason causing cost compare high is: boost voltage exports higher, therefore needs higher withstand voltage electrolytic capacitor; DC-DC switching tube, also because output voltage is high, needs higher withstand voltage switching tube; Because higher power output, therefore need larger inductance component; Because higher voltage, rectifier diode equally also needs higher withstand voltage.
Summary of the invention
The utility model in order to the DC-DC booster circuit input voltage solving available liquid crystal TV LED drive circuit high, cause requiring there is high withstand voltage properties to adopted electronic device and the problem causing cost to increase, propose a kind of liquid crystal television LED drive circuit, can solve the problem.
In order to solve the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of liquid crystal television LED drive circuit, comprise AC-DC converter, described AC-DC converter comprises low pressure and exports winding and LED boost voltage output winding, described low pressure exports winding and exports the supply power voltage be used for for main board power supply, also comprise DC-DC booster circuit, the voltage output end that input and the described low pressure of described booster circuit export winding is connected, the ground end that output and the described LED boost voltage of described booster circuit export winding is connected, and described LED boost voltage exports the voltage output end of winding and is connected with the power input of liquid crystal television LED.
Further, described DC-DC booster circuit comprises inductance and switching circuit, the voltage output end that input and the described low pressure of described inductance export winding is connected, the output ground end that wherein a road and described LED boost voltage export winding is connected, switching circuit of leading up in addition is held with ground and is connected, and the control end of described switching circuit is connected with LED constant current control chip.
Further, described DC-DC booster circuit also comprises diode and filter capacitor, the output of described inductance is wherein leaded up to described diode and is connected with the ground end that described LED boost voltage exports winding, the anode of described diode is connected with the output of described inductance, the ground end that negative electrode and LED boost voltage export winding is connected, the anode of described filter capacitor is connected with the input of described inductance, and negative electrode connects earth terminal.
Further, described switching circuit is a NMOS tube, and the grid of described NMOS tube is connected with LED constant current control chip, and drain electrode is connected with the output of described inductance, and source electrode is connected with ground end by after connection one resistance.
Further, also comprise a detection light adjusting circuit be connected with liquid crystal television LED, described detection light adjusting circuit output detection signal is to described LED constant current control chip.
Further, the output of described inductance is connected with the ground end that described LED boost voltage exports winding by a diode.
Compared with prior art, advantage of the present utility model and good effect are: liquid crystal television LED drive circuit of the present utility model, by low pressure being exported the input of direct voltage as DC-DC booster circuit of winding output, low pressure exports to export and export with LED boost voltage the direct voltage that winding exports after direct voltage that winding exports carries out boost conversion and superposes by DC-DC booster circuit, voltage after superposition is as the driving voltage of LED, driving LED is luminous, make use of the comparatively low dc voltage for main board power supply that low pressure exports winding output cleverly, avoid and directly the comparatively High Level DC Voltage that low pressure output winding exports is boosted, greatly reduce input voltage and the power density of DC-DC booster circuit, thus to its electronic device, not there is high pressure resistant requirement, can reduce costs.
After reading the detailed description of the utility model execution mode by reference to the accompanying drawings, other features of the present utility model and advantage will become clearly.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is a kind of embodiment functional-block diagram of the liquid crystal television LED drive circuit that the utility model proposes;
Fig. 2 is a kind of embodiment circuit theory diagrams of the liquid crystal television LED drive circuit that the utility model proposes.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
Embodiment one, the present embodiment proposes a kind of liquid crystal television LED drive circuit, as shown in Figure 1, comprise AC-DC converter, for AC-input voltage is converted to direct voltage output, AC-DC converter comprises low pressure and exports winding and LED boost voltage output winding, wherein, low pressure exports winding and exports the supply power voltage be used for for main board power supply, be generally 12V direct voltage, LED boost voltage exports the direct voltage of winding output higher than 12V, for driving LED, the liquid crystal television LED drive circuit of the present embodiment also comprises DC-DC booster circuit, the voltage output end that input and the low pressure of booster circuit export winding is connected, the ground end that output and the LED boost voltage of booster circuit export winding is connected, LED boost voltage exports the voltage output end of winding and is connected with the power input of liquid crystal television LED, lower direct voltage boosts by DC-DC booster circuit, and with LED boost voltage export higher direct voltage that winding exports superpose after as the driving voltage of LED.The liquid crystal television LED drive circuit of the present embodiment, by low pressure being exported the input of direct voltage as DC-DC booster circuit of winding output, low pressure exports to export and export with LED boost voltage the direct voltage that winding exports after direct voltage that winding exports carries out boost conversion and superposes by DC-DC booster circuit, voltage after superposition is as the driving voltage of LED, driving LED is luminous, make use of the comparatively low dc voltage for main board power supply that low pressure exports winding output cleverly, avoid and directly the comparatively High Level DC Voltage that low pressure output winding exports is boosted, greatly reduce input voltage and the power density of DC-DC booster circuit, thus to its electronic device, not there is high pressure resistant requirement, can reduce costs.
As a preferred embodiment, as shown in Figure 2, DC-DC booster circuit comprises inductance L and switching circuit, the voltage output end that input and the low pressure of inductance L export winding is connected, the output ground end that wherein a road and described LED boost voltage export winding is connected, switching circuit of leading up in addition is held with ground and is connected, and the control end of described switching circuit is connected with LED constant current control chip.During switching circuit conducting, the direct current that low pressure exports winding output flows through inductance L, switching circuit successively, inductance L carries out accumulation of energy, after switching circuit cut-off, DC-DC booster circuit exports the voltage after boosting, export with LED boost voltage the direct voltage that winding exports to carry out superposing driving LED, the break-make duration of LED constant current control chip control switch circuit, and then make DC-DC booster circuit keep exporting constant voltage, constant current.
As shown in Figure 2, the present embodiment breaker in middle circuit adopts a NMOS tube Q1 to realize, the grid of NMOS tube Q1 is connected with LED constant current control chip, drain electrode is connected with the output of described inductance L, source electrode is connected with ground end by after connection one resistance R, when LED constant current control chip exports high level, NMOS tube Q1 conducting, the direct current that low pressure exports winding output flows through inductance L successively, Q1, R is to ground, inductance L carries out accumulation of energy, during LED constant current control chip output low level, NMOS tube Q1 ends, DC-DC booster circuit exports the voltage after boosting through C7 filtering, export with LED boost voltage the direct voltage that winding exports to carry out superposing driving LED.Certainly, switching circuit of the present utility model is not limited to above-mentioned citing, and the other forms of switching circuit that can realize break-make control can also be adopted to carry out switch control rule.
In order to make, LED constant current control chip is more accurate realizes current constant control and realize dimming function to LED, and also comprise a detection light adjusting circuit be connected with liquid crystal television LED, described detection light adjusting circuit output detection signal is described LED constant current control chip extremely.
Exporting winding output voltage to prevent LED boost voltage oppositely pours in down a chimney in DC-DC booster circuit, damages the electronic component in DC-DC booster circuit, and the output of described inductance L is connected with the ground end that described LED boost voltage exports winding by a diode D1.
Export the ripple in the direct current of winding output to filter out low pressure, the input of DC-DC booster circuit is also connected with a filter capacitor C, and other one end ground connection of filter capacitor C, prevents from causing interference to DC-DC booster circuit.
Certainly; above-mentioned explanation is not to restriction of the present utility model; the utility model is also not limited in above-mentioned citing, the change that those skilled in the art make in essential scope of the present utility model, remodeling, interpolation or replacement, also should belong to protection range of the present utility model.
Claims (6)
1. a liquid crystal television LED drive circuit, comprise AC-DC converter, described AC-DC converter comprises low pressure and exports winding and LED boost voltage output winding, described low pressure exports winding and exports the supply power voltage be used for for main board power supply, it is characterized in that: also comprise DC-DC booster circuit, the voltage output end that input and the described low pressure of described booster circuit export winding is connected, the ground end that output and the described LED boost voltage of described booster circuit export winding is connected, described LED boost voltage exports the voltage output end of winding and is connected with the power input of liquid crystal television LED.
2. liquid crystal television LED drive circuit according to claim 1, it is characterized in that: described DC-DC booster circuit comprises inductance and switching circuit, the voltage output end that input and the described low pressure of described inductance export winding is connected, the output ground end that wherein a road and described LED boost voltage export winding is connected, switching circuit of leading up in addition is held with ground and is connected, and the control end of described switching circuit is connected with LED constant current control chip.
3. liquid crystal television LED drive circuit according to claim 2, it is characterized in that: described DC-DC booster circuit also comprises diode and filter capacitor, the output of described inductance is wherein leaded up to described diode and is connected with the ground end that described LED boost voltage exports winding, the anode of described diode is connected with the output of described inductance, the ground end that negative electrode and LED boost voltage export winding is connected, the anode of described filter capacitor is connected with the input of described inductance, and negative electrode connects earth terminal.
4. liquid crystal television LED drive circuit according to claim 3, it is characterized in that: described switching circuit is a NMOS tube, the grid of described NMOS tube is connected with LED constant current control chip, and drain electrode is connected with the output of described inductance, and source electrode is connected with ground end by after connection one resistance.
5. liquid crystal television LED drive circuit according to claim 2, is characterized in that: also comprise a detection light adjusting circuit be connected with liquid crystal television LED, and described detection light adjusting circuit output detection signal is to described LED constant current control chip.
6. liquid crystal television LED drive circuit according to claim 2, is characterized in that: the output of described inductance is connected with the ground end that described LED boost voltage exports winding by a diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521032864.8U CN205179420U (en) | 2015-12-14 | 2015-12-14 | LCD TV LED drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521032864.8U CN205179420U (en) | 2015-12-14 | 2015-12-14 | LCD TV LED drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205179420U true CN205179420U (en) | 2016-04-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521032864.8U Active CN205179420U (en) | 2015-12-14 | 2015-12-14 | LCD TV LED drive circuit |
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| CN (1) | CN205179420U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105357810A (en) * | 2015-12-14 | 2016-02-24 | 青岛歌尔声学科技有限公司 | Liquid crystal television LED drive circuit |
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2015
- 2015-12-14 CN CN201521032864.8U patent/CN205179420U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105357810A (en) * | 2015-12-14 | 2016-02-24 | 青岛歌尔声学科技有限公司 | Liquid crystal television LED drive circuit |
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