CN205051916U - LED driving circuit and LED driving system employing driving circuit - Google Patents
LED driving circuit and LED driving system employing driving circuit Download PDFInfo
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- CN205051916U CN205051916U CN201520645521.2U CN201520645521U CN205051916U CN 205051916 U CN205051916 U CN 205051916U CN 201520645521 U CN201520645521 U CN 201520645521U CN 205051916 U CN205051916 U CN 205051916U
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Abstract
The utility model provides a LED driving circuit and LED driving system employing driving circuit, LED drive circuit include output circuit, current sample resistance, first power end and second source end. Output circuit includes the power switch, and input voltage is received to its input, and its output is first power end, the one end and the second source end of current sample resistance link to each other other end ground connection. LED drive circuit still includes: control circuit, sampling electric capacity, first switch and second switch, control circuit links to each other with the control end of power switch including feedback end and output, control circuit's output, the one end of first switch links to each other with the second source end, and the other end links to each other with the one end of sampling electric capacity, the other end ground connection of electric capacity of sampling, and the connected node between first switch and the sampling electric capacity links to each other with control circuit's feedback end, second switch one end links to each other other end ground connection with the second source end. Compared with the prior art, the utility model discloses can reduce the power consumption of current sample resistance.
Description
[technical field]
The utility model relates to circuit design field, particularly a kind of LED (Light-EmittingDiode, light-emitting diode) drive circuit and use the LED drive system of this drive circuit.
[background technology]
LED backlight drive circuit is widely used in various electronic equipment, such as, in panel computer and smart mobile phone.And experiment finds in a lot of portable electronic piece system, the half that the consuming electric power of LED screen accounts for whole system power consumption is even more, therefore, improves the efficiency of LED screen, for energy-conservation, reduce heating, extend lithium battery and be full of the service time after electricity highly significant.In prior art, LED-backlit driving chip is usually on the same wafer integrated with control circuit by power NMOSFET (N-type metal-oxide semiconductor fieldeffect transistor), and the general booster circuit that adopts carrys out driving LED lamp.Please refer to shown in Fig. 1, it is the circuit diagram of a kind of LED drive circuit of the prior art, and it comprises boosting output circuit 110, current mode control circuit 120, first power end VP, second source end VN and current sampling resistor Rs.
Described boosting output circuit 110 comprises inductance L 1, diode D1, electric capacity of voltage regulation C2, output capacitance C1 and nmos pass transistor MN1, and wherein, one end of electric capacity of voltage regulation C2 is connected with input voltage VDD, its other end ground connection; One end of inductance L 1 is connected with input voltage VDD, and its other end is connected with the positive pole of diode D1, and the negative pole of diode D1 is through output capacitance C1 ground connection; The drain electrode of nmos pass transistor MN1 is connected with the connected node between inductance L 1 and the positive pole of diode D1, its source ground, and its grid is as the control end of described boosting output circuit 110; Connected node between the negative pole of diode D1 and output capacitance C1 is as the first power end VP of LED drive circuit.One end of current sampling resistor Rs is connected with the second source end VN of LED drive circuit, its other end ground connection.Current mode control circuit 120 comprises feedback end FB, current sample end CurSens and output DRV, wherein, current sample end CurSens is connected with the drain electrode of nmos pass transistor MN1, and feedback end FB is connected with second source end VN, and output DRV is connected with the grid of nmos pass transistor MN1.In order to simplified characterization, only between the first power end VP and second source end VN of LED drive circuit, be connected to a LED channel in Fig. 1, this passage comprises WLED1, WLED2 and WLED3 (white light diode) of connecting successively.
In order to realize feedback loop stable, in Fig. 1, have employed current-mode structure, namely by the electric current of a part of nmos pass transistor MN1 of sampling, and injecting sample rate current to feedback control loop.But the LED drive circuit in Fig. 1 also has its shortcoming, namely can there is certain pressure drop in current sampling resistor Rs, will extra power be consumed, thus reduce the efficiency of whole system.
Therefore, be necessary that the technical scheme proposing a kind of improvement solves the problems referred to above.
[utility model content]
The purpose of this utility model is the LED drive system providing a kind of LED drive circuit and use this drive circuit, and it can reduce the power loss of current sampling resistor in LED drive circuit, thus improves the efficiency of whole system.
To achieve these goals, according to an aspect of the present utility model, the utility model provides a kind of LED drive circuit, it comprises output circuit, current sampling resistor, the first power end and second source end, described output circuit comprises power switch, its input receives input voltage, and its output is the first power end, and input voltage is converted to output voltage by it; One end of current sampling resistor is connected with second source end, its other end ground connection.
Described LED drive circuit also comprises: control circuit, sampling capacitance, the first switch and second switch, control circuit comprises feedback end and output, wherein, the output of described control circuit is connected with the control end of power switch, the feedback voltage that described control circuit receives based on its feedback end, by its output output switch control signal to the control end of power switch, to control power switch conducting or cut-off; One end of first switch is connected with described second source end, and its other end is connected with one end of sampling capacitance, the other end ground connection of sampling capacitance, and the connected node between the first switch and sampling capacitance is connected with the feedback end of described control circuit; Second switch one end is connected with described second source end, its other end ground connection.
Further, described output circuit also comprises inductance L 1, diode D1, output capacitance C1, and wherein one end of inductance L 1 is connected with input voltage, and its other end is connected with the positive pole of diode D1, and the negative pole of diode D1 is through output capacitance C1 ground connection; First link of power switch is connected with the connected node between inductance L 1 and the positive pole of diode D1, and its second link ground connection, the connected node between the negative pole of diode D1 and output capacitance C1 is as the first power end.
Further, described control circuit also includes current sample end, and this current sample end is connected with the first link of power switch, and the electric current that described control end samples based on current sample end and feedback voltage produce described switch controlling signal.
Further, when the first switch is switched on, second switch is turned off, by the first switch by the voltage sample on current sampling resistor on sampling capacitance, control circuit carries out loop adjustment using the voltage on current sampling resistor as feedback voltage; When the first switch be turned off, second switch be switched on time, described control circuit directly carries out loop adjustment using the voltage on sampling capacitance as feedback voltage.Described LED drive circuit also comprises oscillator, described oscillator for generation of and export the first clock signal and second clock signal, wherein, first clock signal is connected with the control end of the first switch, it is for controlling the first switch conduction or shutoff, second clock signal is connected with the control end of second switch, and it is for controlling second switch conducting or shutoff.
Further, the significant level of the first clock signal C K1 and the significant level of second clock signal CK2 not overlapping, second clock signal is that the hopping edge of inactive level to be become significant level hopping edge to the first its immediate clock signal from inactive level exists Td time of delay from significant level saltus step, the significant level of clock signal is the level signal making corresponding switch conduction, the inactive level of clock signal is the level signal making corresponding switch OFF, and described time of delay, Td was greater than the stabilization time required for feedback control loop at current mode control circuit place.
Further, described oscillator also exports the 3rd clock signal, and described 3rd clock signal is connected with the clock signal terminal of described control circuit, and described control circuit worked with the clock cycle of the 3rd clock signal.
Further, second clock signal and the 3rd clock signal synchronization, and in the one-period of second clock signal, the inactive level duration of second clock signal is the integral multiple of the clock cycle of the 3rd clock signal, wherein, the invalid logic level of second clock signal is the level signal that second switch is turned off.
Further, the bandwidth of control circuit is lower than the frequency of the first clock signal.
Further, described control circuit comprises error amplifier and building-out capacitor, and described building-out capacitor is series at the output of described error amplifier.
According to another aspect of the present utility model, the utility model provides a kind of LED drive system, and it comprises one or more LED and LED drive circuit.LED drive circuit, it comprises output circuit, current sampling resistor, the first power end and second source end, and described output circuit comprises power switch, and its input receives input voltage, its output is the first power end, and input voltage is converted to output voltage by it; One end of current sampling resistor is connected with second source end, its other end ground connection.Described LED drive circuit also comprises: control circuit, sampling capacitance, the first switch and second switch, control circuit comprises feedback end and output, wherein, the output of described control circuit is connected with the control end of power switch, the feedback voltage that described control circuit receives based on its feedback end, by its output output switch control signal to the control end of power switch, to control power switch conducting or cut-off; One end of first switch is connected with described second source end, and its other end is connected with one end of sampling capacitance, the other end ground connection of sampling capacitance, and the connected node between the first switch and sampling capacitance is connected with the feedback end of described control circuit; Second switch one end is connected with described second source end, its other end ground connection.The negative pole of described LED is connected with the second source end of LED drive circuit, and its positive pole is connected with the first power end.
Compared with prior art, the utility model sets up sampling capacitance C3 in existing LED drive circuit, with the voltage of intermittent sample rate current sampling resistor Rs; Current sampling resistor Rs is shorted to ground during non-sampled, using the voltage on sampling capacitance C3 as Current feedback voltage, thus reduces the power consumption on current sampling resistor Rs, improve the efficiency of whole system.
[accompanying drawing explanation]
In order to be illustrated more clearly in the technical scheme of the utility model embodiment, below the accompanying drawing used required in describing embodiment is briefly described, 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.Wherein:
Fig. 1 is the circuit diagram of a kind of LED drive circuit of the prior art;
Fig. 2 is the circuit diagram of the utility model LED drive circuit in one embodiment;
Fig. 3 is in one embodiment, the sequential chart of the first clock signal C K1 in Fig. 2 and second clock signal CK2.
[embodiment]
Detailed description of the present utility model carrys out the running of direct or indirect simulation technical solutions of the utility model mainly through program, step, logical block, process or other symbolistic descriptions.For thorough understanding the utility model, in ensuing description, set forth a lot of specific detail.And when not having these specific detail, the utility model then may still can realize.Affiliated those of skill in the art use the work that these describe and statement effectively introduces them to the others skilled in the art in affiliated field herein essential.In other words, be the purpose of this utility model of avoiding confusion, due to the method known and program easy understand, therefore they are not described in detail.
Alleged herein " embodiment " or " embodiment " refers to special characteristic, structure or the characteristic that can be contained at least one implementation of the utility model.Different local in this manual " in one embodiment " occurred not all refers to same embodiment, neither be independent or optionally mutually exclusive with other embodiments embodiment.
Please refer to shown in Fig. 2, it is the circuit diagram of the utility model LED drive circuit in one embodiment.As shown in Figure 2, described LED drive circuit comprises boosting output circuit 210, control circuit 220 (or being referred to as current mode control circuit), the first power end VP, second source end VN, current sampling resistor Rs, sampling capacitance C3, the first K switch 1 and second switch K2.
Described boosting output circuit 210 is identical with the boosting output circuit 110 in Fig. 1, described boosting output circuit 210 comprises inductance L 1, diode D1, electric capacity of voltage regulation C2, output capacitance C1 and power switch 212, wherein, one end of electric capacity of voltage regulation C2 is connected with input voltage VDD, its other end ground connection; One end of inductance L 1 is connected with input voltage VDD, and its other end is connected with the positive pole of diode D1, and the negative pole of diode D1 is through output capacitance C1 ground connection; First link of power switch 212 is connected with the connected node between inductance L 1 and the positive pole of diode D1, its second link ground connection, and its control end is as the control end of described boosting output circuit 210; Connected node between the negative pole of diode D1 and output capacitance C1 as the output of the output circuit 210 that boosts, i.e. the first power end VP of LED drive circuit.By controlling power switch 212 conducting or shutoff, boosting output circuit 210 couples of input voltage VDD can be made to carry out boost conversion, thus make the output voltage values of the first power end VP higher than input voltage VDD.In the enforcement embodiment shown in Fig. 2, described power switch 212 is nmos pass transistor MN1, and the first link of power switch 212, the second link and control end are respectively the drain electrode of nmos pass transistor MN1, source electrode and grid.In another embodiment, power switch 212 also can be PMOS transistor.
One end of current sampling resistor Rs is connected with the second source end VN of LED drive circuit, its other end ground connection, and the voltage that current sampling resistor Rs is formed is called Current feedback voltage, the electric current in this Current feedback voltage reflection LED channel.In order to simplified characterization, only between the first power end VP and second source end VN of LED drive circuit, a LED channel is connected in Fig. 2, this passage comprises WLED1, WLED2 and WLED3 (white light diode) of connecting successively in actual applications, LED drive circuit in Fig. 2 can drive LED multi-path passage, such as, 16 paths of LEDs passages, can comprise a LED or multiple LED connected successively in each LED channel.
Described control circuit 220 comprises feedback end FB, current sample end CurSens and output DRV, wherein, current sample end CurSens is connected with the first link of power switch 212, output DRV is connected with the control end of power switch 212, the electric current of described current mode control circuit 220 by its current sample end CurSens sampled power switch 212 flows through, receives feedback voltage by its feedback end FB.The electric current that described current mode control circuit 220 samples based on its current sample end CurSens and the feedback voltage that its feedback end FB receives by its output DRV output switch control signal to the control end of power switch 212, to control power switch 212 conducting or cut-off.Detailed operation about described current mode control circuit 220 does not affect the enforcement of the technical solution of the utility model, and described current mode control circuit 220 can adopt any one current-mode control technology of the prior art, so place repeats no more.In addition, in some embodiments, also can not gather the electric current that power switch 212 flows through completely, only based on the feedback voltage output switch control signal that its feedback end FB receives, the effect of the electric current that control LED flows through can be realized equally.
Compared to Figure 1, the LED drive circuit in Fig. 2 adds sampling capacitance C3, the first K switch 1, second switch K2 and oscillator OSC.Wherein, one end of first K switch 1 is connected with described second source end VN, its other end is connected with one end of sampling capacitance C3, the other end ground connection of sampling capacitance C3, and the connected node between the first K switch 1 and sampling capacitance C3 is connected with the feedback end FB of described control circuit 220; Second switch K2 one end is connected with described second source end VN, its other end ground connection (namely second switch K2 is in parallel with described current sampling resistor Rs); Described oscillator OSC output drive signal, to control conducting or the shutoff of the first K switch 1 and second switch K2, wherein, when control first K switch 1 conducting, controls second switch K2 and turns off; When controlling second switch K2 conducting, controlling the first K switch 1 and turning off.Specific works principle is: when the first K switch 1 conducting, second switch K2 turn off, by the first K switch 1 by the voltage sample on current sampling resistor Rs on sampling capacitance C3, current mode control circuit 220 carries out loop adjustment using the voltage on current sampling resistor Rs as feedback voltage, equals the reference voltage preset by the Voltage Cortrol on current sampling resistor Rs; When the first K switch 1 turn off, second switch K2 conducting time, the voltage of sampling capacitance C3 not on sample rate current sampling resistor Rs, control circuit 220 carries out loop adjustment using the voltage (i.e. the aforementioned voltage be upsampled to from current sampling resistor Rs) on sampling capacitance C3 as feedback voltage, the reference voltage preset is equaled by the Voltage Cortrol on sampling capacitance C3, and due to current sampling resistor Rs by second switch K2 be shorted to ground, therefore, now, voltage on resistance Rs is zero, no longer consumed energy, thus realize the effect of saving power consumption.Suppose that the conducting duty ratio of second switch K2 is 90%, then 90% current sampling resistor Rs on power consumption will be saved, the average power consumption of the current sampling resistor Rs namely in Fig. 2 will be reduced to the 100%-90%=10% of prior art, therefore the conducting duty ratio of second switch K2 is higher in the utility model, on current sampling resistor Rs, saving volume power consumption is more.It should be noted that, the conducting duty ratio (i.e. duty cycle of switching) of switch refers in a switch periods, the duration of this switch conduction and the ratio of whole switch periods.
Because general current mode control circuit 220 also needs oscillator, therefore, the oscillator can using current mode control circuit 220 in the utility model additionally produces the drive singal of control first K switch 1 and second switch K2.In the embodiment shown in Figure 2, oscillator OSC produces and exports described drive singal and the 3rd clock signal C K3, and drive singal comprises the first clock signal C K1 and second clock signal CK2.Wherein, 3rd clock signal C K3 is connected with the clock end CK3 of current mode control circuit 220,3rd clock signal C K3 is used for the clock for current mode control circuit 220 provides pulse-width adjustment to control, namely for controlling the clock signal of power switch 212 conducting or cut-off, the frequency of the 3rd clock signal C K3 is identical with the frequency of cut-off with power switch 212 conducting; First clock signal C K1 is connected with the control end of the first K switch 1, to control conducting or the shutoff of the first K switch 1; Second clock signal CK2 is connected with the control end of second switch K2, to control conducting or the shutoff of second switch K2.
Please refer to shown in Fig. 3, it is in one embodiment, the sequential chart of the first clock signal C K1 in Fig. 2 and second clock signal CK2.When first clock signal C K1 is the first logic level, make the first K switch 1 conducting, when the first clock signal C K1 is the second logic level, the first K switch 1 is turned off; When second clock signal CK2 is the first logic level, make second switch K2 conducting, when second clock signal CK2 is the second logic level, second switch K2 is turned off.In the embodiment shown in fig. 3, first logic level of the first clock signal C K1 and second clock signal CK2 is high level; Second logic level of the first clock signal C K1 and second clock signal CK2 is low level.In another kind statement, drive the level of the first K switch 1 and second switch K2 conducting, can be referred to as significant level, the level driving the first K switch 1 and second switch K2 to end, can be referred to as inactive level.
In Fig. 3, the first clock signal C K1 and second clock signal CK2 meets following condition.
First, first clock signal C K1 and second clock signal CK2 is not overlapping clock, namely significant level is not overlapping, to avoid the first K switch 1 and second switch K2 conducting simultaneously, such as, in figure 3, the high level (it makes second switch K2 conducting) of high level (it makes the first K switch 1 conducting) and the second clock signal K2 of the first clock signal C K1 is not overlapping mutually.
Second, second clock signal CK2 is synchronous with the 3rd clock signal C K3, and the time that second clock signal CK2 is low level (i.e. the second logic level) should be the integral multiple of the 3rd clock signal C K3 clock cycle, its reason is, current mode control circuit 220 worked with the clock cycle of the 3rd clock signal C K3, the time (time that corresponding second switch K2 is turned off) worked for current sampling resistor Rs should be the time of whole power switch 212 turn-on and turn-off, like this, within the work period of a power switch 212 (namely in the pulse width modulation controlled cycle) can be avoided to occur that part-time current sampling resistor Rs is series at one end of LED channel, the situation that another part time current sampling resistor Rs is shorted.If there is above-mentioned situation, appearance improper pulse width modulation cycle will be caused, thus cause feedback control loop unstable.If feedback control loop is unstable, then can produces the phenomenon of the flickers such as LED, produce bad visual effect.
Three, there is larger Td time of delay to the rising edge (namely the first clock signal C K1 is the hopping edge of the first logic level by the second logic level saltus step) of the first its immediate clock signal C K1 in the trailing edge (namely second clock signal CK2 is the hopping edge of the second logic level by the first logic level saltus step) of second clock signal CK2, and time of delay, Td needed stabilization time of being greater than required for the loop at current mode control circuit place.
A designing requirement is in addition, because the voltage on current sampling resistor Rs in the utility model is only sampled by batch (-type), and current mode control circuit carrys out work with this average voltage, therefore, in order to ensure that averaging model is correct, holding circuit mould controls the stability of feedback control loop, and the bandwidth of going back demand fulfillment current mode control circuit will lower than the frequency (i.e. the frequency of the first clock signal C K1) of the utility model discontinuous formula sampling.By increasing building-out capacitor (being generally the output of error amplifier of being connected by building-out capacitor), the bandwidth of current mode control circuit can be reduced.
In sum, the utility model is in existing LED drive circuit, increase sampling capacitance C3, the first K switch 1, second switch K2, wherein, one end of first K switch 1 is connected with described second source end VN, its other end is connected with one end of sampling capacitance C3, the other end ground connection of sampling capacitance C3, and the connected node between the first K switch 1 and sampling capacitance C3 is connected with the feedback end FB of described current mode control circuit 220; Second switch K2 one end is connected with described second source end VN, its other end ground connection.By controlling the first K switch 1 and second switch K2 alternate conduction, make the voltage of sampling capacitance C3 intermittent sample rate current sampling resistor Rs; Current sampling resistor Rs is shorted to ground during non-sampled, using the voltage on sampling capacitance C3 as Current feedback voltage, thus reduces the power consumption on current sampling resistor Rs, improve the efficiency of whole system.
Above-mentioned explanation fully discloses embodiment of the present utility model.It is pointed out that the scope be familiar with person skilled in art and any change that embodiment of the present utility model is done all do not departed to claims of the present utility model.Correspondingly, the scope of claim of the present utility model is also not limited only to previous embodiment.
Claims (10)
1. a LED drive circuit, it comprises output circuit, current sampling resistor, the first power end and second source end, described output circuit comprises power switch, its input receives input voltage, its output is the first power end, and input voltage is converted to output voltage by it, and one end of current sampling resistor is connected with second source end, its other end ground connection
It is characterized in that, described LED drive circuit also comprises: control circuit, sampling capacitance, the first switch and second switch,
Control circuit comprises feedback end and output, wherein, the output of described control circuit is connected with the control end of power switch, the feedback voltage that described control circuit receives based on its feedback end, by its output output switch control signal to the control end of power switch, to control power switch conducting or cut-off
One end of first switch is connected with described second source end, and its other end is connected with one end of sampling capacitance, the other end ground connection of sampling capacitance, and the connected node between the first switch and sampling capacitance is connected with the feedback end of described control circuit; Second switch one end is connected with described second source end, its other end ground connection.
2. LED drive circuit according to claim 1, it is characterized in that, described output circuit also comprises inductance L 1, diode D1, output capacitance C1, wherein one end of inductance L 1 is connected with input voltage, its other end is connected with the positive pole of diode D1, and the negative pole of diode D1 is through output capacitance C1 ground connection; First link of power switch is connected with the connected node between inductance L 1 and the positive pole of diode D1, and its second link ground connection, the connected node between the negative pole of diode D1 and output capacitance C1 is as the first power end.
3. LED drive circuit according to claim 2, it is characterized in that, described control circuit also includes current sample end, this current sample end is connected with the first link of power switch, and the electric current that described control end samples based on current sample end and feedback voltage produce described switch controlling signal.
4. LED drive circuit according to claim 1, it is characterized in that, when the first switch is switched on, second switch is turned off, by the first switch by the voltage sample on current sampling resistor on sampling capacitance, control circuit carries out loop adjustment using the voltage on current sampling resistor as feedback voltage; When the first switch be turned off, second switch be switched on time, described control circuit directly carries out loop adjustment using the voltage on sampling capacitance as feedback voltage,
Described LED drive circuit also comprises oscillator, described oscillator for generation of and export the first clock signal and second clock signal, wherein, first clock signal is connected with the control end of the first switch, it is for controlling the first switch conduction or shutoff, second clock signal is connected with the control end of second switch, and it is for controlling second switch conducting or shutoff.
5. LED drive circuit according to claim 4, it is characterized in that, the significant level of the first clock signal C K1 and the significant level of second clock signal CK2 not overlapping, second clock signal is that the hopping edge of inactive level to be become significant level hopping edge to the first its immediate clock signal from inactive level exists Td time of delay from significant level saltus step, the significant level of clock signal is the level signal making corresponding switch conduction, the inactive level of clock signal is the level signal making corresponding switch OFF, described time of delay, Td was greater than the stabilization time required for feedback control loop at current mode control circuit place.
6. LED drive circuit according to claim 5, it is characterized in that, described oscillator also exports the 3rd clock signal, and described 3rd clock signal is connected with the clock signal terminal of described control circuit, and described control circuit worked with the clock cycle of the 3rd clock signal.
7. LED drive circuit according to claim 6, it is characterized in that, second clock signal and the 3rd clock signal synchronization, and in the one-period of second clock signal, the inactive level duration of second clock signal is the integral multiple of the clock cycle of the 3rd clock signal, wherein, the invalid logic level of second clock signal is the level signal that second switch is turned off.
8. LED drive circuit according to claim 4, is characterized in that,
The bandwidth of control circuit is lower than the frequency of the first clock signal.
9. LED drive circuit according to claim 8, is characterized in that, described control circuit comprises error amplifier and building-out capacitor, and described building-out capacitor is series at the output of described error amplifier.
10. a LED drive system, is characterized in that, it comprise one or more LED and as arbitrary in claim 1-9 as described in LED drive circuit,
The negative pole of described LED is connected with the second source end of LED drive circuit, and its positive pole is connected with the first power end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520645521.2U CN205051916U (en) | 2015-08-25 | 2015-08-25 | LED driving circuit and LED driving system employing driving circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520645521.2U CN205051916U (en) | 2015-08-25 | 2015-08-25 | LED driving circuit and LED driving system employing driving circuit |
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| CN205051916U true CN205051916U (en) | 2016-02-24 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105101560A (en) * | 2015-08-25 | 2015-11-25 | 无锡中星微电子有限公司 | LED drive circuit and LED drive system using same |
| CN107453881A (en) * | 2017-08-08 | 2017-12-08 | 博为科技有限公司 | A kind of bypass circuit and PSE device |
-
2015
- 2015-08-25 CN CN201520645521.2U patent/CN205051916U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105101560A (en) * | 2015-08-25 | 2015-11-25 | 无锡中星微电子有限公司 | LED drive circuit and LED drive system using same |
| CN107453881A (en) * | 2017-08-08 | 2017-12-08 | 博为科技有限公司 | A kind of bypass circuit and PSE device |
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| C56 | Change in the name or address of the patentee | ||
| CP01 | Change in the name or title of a patent holder |
Address after: A 530 Taihu international science and Technology Park building 214028 Qingyuan Road in Jiangsu province Wuxi City District 10 layer Patentee after: WUXI ZHONGGAN MICROELECTRONIC CO., LTD. Address before: A 530 Taihu international science and Technology Park building 214028 Qingyuan Road in Jiangsu province Wuxi City District 10 layer Patentee before: Wuxi Vimicro Co., Ltd. |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20160224 Effective date of abandoning: 20170510 |
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| AV01 | Patent right actively abandoned |