CN102014536A

CN102014536A - Drive circuit and light-emitting diode drive controller

Info

Publication number: CN102014536A
Application number: CN2009101714440A
Authority: CN
Inventors: 徐献松; 柳娟娟
Original assignee: Dengfeng Microelectronics Co Ltd
Current assignee: Dengfeng Microelectronics Co Ltd; Green Solution Technology Co Ltd
Priority date: 2009-09-04
Filing date: 2009-09-04
Publication date: 2011-04-13

Abstract

The invention provides a drive circuit and a light-emitting diode drive controller. The drive circuit is used for driving a load. The drive circuit comprises a drive power supply and a controller, wherein the drive power supply is used for providing a first power supply for driving the load, and the controller is coupled to a second power supply for receiving electric power required by the operation and used for controlling the electric power provided to the load by the drive power supply when in a first mode and stopping the drive power supply to provide the electric power to the load when in a second mode, wherein the controller is maintained in the first mode before the drive power supply provides the first power supply.

Description

Drive circuit and light-emitting diode driving governor

Technical field

The present invention relates to one drive circuit and light-emitting diode driving governor, refer to a kind of drive circuit and light-emitting diode driving governor especially with latch protection.

Background technology

Please refer to Fig. 1, be the circuit diagram of the drive circuit of a known tool defencive function.Drive circuit comprises a change-over circuit and a controller 10 that is made of an inductance L, a diode D, a transistor switch SW, a capacitor C, in order to drive a load 30.One resistance R couples load 30, produces a feedback signal FB with the size of current according to the load 30 of flowing through.Controller 10 produces the conducting of a control signal Gate oxide-semiconductor control transistors switch SW according to feedback signal FB and ends, and to adjust the electric power that is sent to the output of change-over circuit by an input voltage VIN, the current stabilization that makes the load 30 of flowing through is in a current value.

Controller 10 comprises an error amplifying circuit 12, an oscillating circuit 14, a pulse-width modulation circuit 16, a Drive and Control Circuit 18 and a protective circuit 20.Error amplifying circuit 12 receives a reference voltage Vref and feedback signal FB, and produces an error amplification signal COMP in view of the above.The ramp signal SAW that pulse-width modulation circuit 16 reception error amplification signal COMP and oscillating circuit 14 are exported is to produce a pulse-width modulation signal PWM.Drive and Control Circuit 18 produces control signal Gate with the oxide-semiconductor control transistors switch SW according to pulse-width modulation signal PWM.Protective circuit 20 is exported a guard signal PROT to Drive and Control Circuit 18 when driving circuit abnormality, make Drive and Control Circuit 18 temporarily stop to export control signal Gate, transmits electric power to change-over circuit to stop input voltage VIN.When circuit abnormality was removed, protective circuit 20 stopped output protection signal PROT, made Drive and Control Circuit 18 export control signal Gate again with the oxide-semiconductor control transistors switch SW.

Yet general in case circuit abnormality occurs, for example output voltage is unusual or output current is unusual, and controller 10 stops to export behind the control signal Gate that circuit abnormality can disappear but is not the reason that basic eliminating causes circuit abnormality.Therefore controller 10 is exported control signal Gate again circuit abnormality is occurred again after.So going round and beginning again not only circuit still can't normal operation, has also increased unnecessary power consumption, and has caused the unstable of circuit even made circuit increase the risk of damaging.

Summary of the invention

Increased unnecessary power consumption in view of the design of controller defencive function of the prior art makes drive circuit when the circuit abnormality, and caused the unstable of circuit and increase risk of damage.Drive circuit of the present invention and controller are in circuit abnormality; keep drive circuit under protected mode, to restart until drive circuit; problem with the drive circuit of avoiding prior art; and for the duplicate supply drive circuit; increase the judgement of the power supply of drive circuit, can't move to avoid the circuit erroneous judgement.

For achieving the above object, the invention provides a kind of light-emitting diode driving governor, in order to control a LED driving circuit to drive a light-emitting diode (LED) module.The light-emitting diode driving governor comprises a feedback control unit and a protected location.Feedback control unit is exported a control signal to adjust drive current according to the flow through current feedback signal of a drive current size of light-emitting diode (LED) module of representative.Whether protected location produces a guard signal according to current feedback signal with decision, is restarted until the light-emitting diode driving governor to stop the LED driving circuit output driving current.

The present invention also provides a kind of drive circuit, in order to drive a load.Drive circuit comprises a driving power and a controller.Driving power is in order to provide one first power supply to drive load.Controller couples a second source receiving the operation required electric power, and the electric power size of load is provided and provides load electric in order to stop driving power during in one second pattern in order to the controlling and driving power supply when one first pattern.Wherein, controller is before driving power provides first power supply, and quiescing is in this second pattern.

The present invention can adjust the work period of control signal, provides electric power size to load with adjustment, and whether stops to provide load electric according to guard signal with decision.The present invention can provide the low-voltage variation signal, crossed the high pressure guard signal, crossed the low current guard signal, excessive current guard signal or other arbitrary lasting generations in order to the protection detection signal of detecting drive circuit surpass scheduled time length/during number of times; protected location is the output protection signal, to avoid the temporary circuit abnormality of drive circuit.

Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify claim scope of the present invention.And relevant other objects and advantages of the present invention will be set forth in follow-up explanation and accompanying drawing.

Description of drawings

Fig. 1 is the circuit diagram of the drive circuit of a known tool defencive function.

Fig. 2 is the circuit diagram according to the drive circuit of one first preferred embodiment of the present invention.

Fig. 3 is the circuit diagram according to the drive circuit of one second preferred embodiment of the present invention.

[main element description of reference numerals]

Prior art:

Controller 10

Error amplifying circuit 12

Oscillating circuit 14

Pulse-width modulation circuit 16

Drive and Control Circuit 18

Protective circuit 20

Load 30

Inductance L

Diode D

Transistor switch SW

Capacitor C

Resistance R

Feedback signal FB

Control signal Gate

Input voltage VIN

Reference voltage Vref

Error amplification signal COMP

Ramp signal SAW

Pulse-width modulation signal PWM

Guard signal PROT

The present invention:

Controller 100,200

Vibration unit 102

Error is amplified unit 104,212

Pulsewidth unit of adjustment 106

Pulse-width modulation signal 107

Drive controlling unit 108

Feedback control unit 110,210

Protected location 120,220

Cross low pressure comparative unit 122,222

Cross high pressure ratio than unit 124,224

Cross low current comparative unit 126,226

Excessive current comparative unit 128,228

Current-sensing circuit 132,232

Voltage detection circuit 134,234

Switch 140,240

Inductance 142

Diode 144

Load 145,245

Output capacitance 146

With door 214

Protection start unit 215

Inverter 216

Single-shot trigger circuit 218

Driving power 250

Input voltage VIN

Output voltage VO UT

Voltage feedback signal VFB, Vs

Control signal S1, S2

Reference signal Vr1, Vr2

Error amplification signal Vea

Guard signal PROT

Cross low pressure reference signal Vuvp

Cross low-voltage variation signal UVP

Too high pressure reference signal Vovp

Cross high pressure guard signal OVP

Cross low current reference signal Vucp

Current feedback signal IFB, Cs

Drive current Iload

Cross low current guard signal UCP

Excessive current reference signal Vocp

Excessive current guard signal OCP

The first power vd DH

Second source VDDL

Dim signal DIM

Point A, B, C

Embodiment

Please refer to Fig. 2, be circuit diagram according to the drive circuit of one first preferred embodiment of the present invention.Drive circuit comprises a controller 100 and a driving power, and in order to drive a load 145, wherein driving power comprises an input voltage VIN, a switch 140, an inductance 142, a diode 144 and an output capacitance 146.At present embodiment, driving power is the DC boosting change-over circuit that always circulates, in order to input voltage VIN is converted to an output voltage VO UT, to drive load 145.Controller 100 receives a voltage feedback signal VFB who is produced by a voltage detection circuit 134, voltage feedback signal VFB represents the size of the output voltage VO UT that drive circuit provides, and produce the switching of a control signal S1 in view of the above with control switch 140, make output voltage VO UT stable.

Controller 100 comprises a feedback control unit 110 and a protected location 120.Feedback control unit 110 comprises a vibration unit 102, an error is amplified unit 104, a pulsewidth unit of adjustment 106 and a drive controlling unit 108.Error is amplified unit 104 and is received a voltage feedback signal VFB and a reference signal Vr1, and produces an error amplification signal Vea in view of the above.Pulsewidth unit of adjustment 106 couples vibration unit 102 and error is amplified unit 104, reaches a triangular signal that is produced by vibration unit 102 and produces a pulse-width modulation signal 107 in view of the above to receive error amplification signal Vea.Drive controlling unit 108 couples pulsewidth unit of adjustment 106 and protected location 120, with a guard signal PROT who receives pulse-width modulation signal 107 and produced by protected location 120.Whether drive controlling unit 108 adjusts work period of control signal S1 according to pulse-width modulation signal 107, provides electric power size to load with adjustment, and stop to provide load 145 electric power according to guard signal PROT with decision.

Controller 100 more comprises one, and low pressure comparative unit 122, a mistake high pressure ratio are crossed a low current comparative unit 126 and an excessive current comparative unit 128 than unit 124, excessively.Cross low pressure comparative unit 122 reception voltage feedback signal VFB and and cross low pressure reference signal Vuvp; when the accurate position of voltage feedback signal VFB was lower than the accurate position of low pressure reference signal Vuvp, promptly output voltage VO UT was lower than when being scheduled to low voltage value output one and crosses low-voltage variation signal UVP.Cross high pressure ratio and receive a voltage feedback signal VFB and a too high pressure reference signal Vovp than unit 124; when the accurate position of voltage feedback signal VFB was higher than the accurate position of too high pressure reference signal Vovp, high pressure guard signal OVP was crossed in output one when promptly output voltage VO UT was higher than a predetermined too high voltages value.Cross low current comparative unit 126 and receive a current feedback signal IFB who crosses low current reference signal Vucp and produced by a current-sensing circuit 132; current feedback signal IFB represents the size of the drive current Iload of the load 145 of flowing through; when the accurate position of current feedback signal IFB was lower than the standard position of low current reference signal Vucp, promptly load current Iload be lower than when being scheduled to low current value output one low current guard signal UCP.Excessive current comparative unit 128 received current feedback signal IFB and an excessive current reference signal Vocp; when the accurate position of current feedback signal IFB is higher than the accurate position of excessive current reference signal Vocp, export an excessive current guard signal OCP when promptly drive current Iload is higher than a predetermined excessive current value.When protected location 120 in a single day received low-voltage variation signal UVP, crossed high pressure guard signal OVP, when crossing low current guard signal UCP, excessive current guard signal OCP arbitrary; be output protection signal PROT with stop control 100 output control signal S1, make driving power no longer transmit electric power to load 145 till controller 100 is restarted.That is to say that when controller 100 ran into circuit abnormality, controller 100 promptly was lockable (latch) in protected mode, constantly attempt the normal circuit start to avoid circuit.Generally speaking; controller 100 can restart signal (not drawing) to protected location 120 by one of outside; protected location 120 is removed to be pinned to stop output protection signal PROT again; perhaps stop to provide controller 100 required electric power, controller 100 internal circuit status are reseted again.

Except an above-mentioned generation circuit abnormality promptly enters the protected mode; the present invention also can cross low-voltage variation signal UVP, cross high pressure guard signal OVP, cross low current guard signal UCP, excessive current guard signal OCP or other arbitrary lasting generations in order to the protection detection signal of detecting drive circuit surpasses a scheduled time during length; protected location 120 is output protection signal PROT; to avoid the temporary circuit abnormality of drive circuit; for example: artificial rocking or touching, and the circuit that causes erroneous judgement.Perhaps; the present invention also can cross low-voltage variation signal UVP, cross high pressure guard signal OVP, cross low current guard signal UCP, excessive current guard signal OCP or other number of times in order to arbitrary generation of the protection detection signal of detecting drive circuit when surpassing a pre-determined number (for example: 3 times), the just output protection signal PROT circuit erroneous judgement of avoiding temporary transient circuit abnormality to cause of protected location 120.

The foregoing description is the example explanation with the DC-DC voltage up converting circuit of Voltage Feedback control, yet the present invention also can be applied to any drive circuit with defencive function.Please refer to Fig. 3, be circuit diagram according to the drive circuit of one second preferred embodiment of the present invention.The drive circuit of present embodiment is the two-supply circuit system, and just driving the power supply of load and the power supply of driving governor is power supply independent of each other.

See also Fig. 3, drive circuit has comprised a controller 200 and a driving power 250.Driving power 250 is in order to provide one first power vd DH to drive load 245, and at this embodiment, load 245 is a light-emitting diode (LED) module.Controller 200 couples a second source VDDL to receive the operation required electric power.When drive circuit did not have any circuit abnormality, controller 200 operated in one first pattern, i.e. normal mode, and controller 200 outputs this moment one control signal S2 control switch 240 provides the electric power size of load 245 with controlling and driving power supply 250.When controller 200 was judged drive circuit generation circuit abnormality, controller 200 operated in one second pattern, and promptly protected mode provides load 245 electric power to stop driving power 250.In addition, input to controller 200 and may judge circuit abnormality by accident and enter protected mode for avoiding the first power vd DH to be later than second source VDDL.Therefore, controller of the present invention 200 can judge whether driving power 250 has begun to provide the first power vd DH, if not then quiescing in second pattern.

Controller 200 comprises a feedback control unit 210 and a protected location 220.Feedback control unit 210 comprises an error and amplifies unit 212 and one and 214.Error is amplified the current feedback signal Cs that unit 212 receives a reference signal Vr2 and produced by a current-sensing circuit 232, and current feedback signal Cs represents the size of the drive current of the load 245 of flowing through, and produces a control signal S2 in view of the above.At present embodiment, the equivalent resistance of control signal S2 control switch is stable at a predetermined current value with control flows through the drive current of load.Couple error with door and amplify unit 212 and protected location 220, reach a guard signal PROT who is produced by protected location 220 to receive a dim signal DIM, and whether stop to provide load 245 electric power with decision according to guard signal PROT and dim signal DIM.

Controller 200 more comprises a protection start unit 215, to be crossed low pressure comparative unit 222, and crosses high pressure ratio and cross a low current comparative unit 226 and an excessive current comparative unit 228 than unit 224,, wherein protects start unit 215 to comprise an inverter 216, a single-shot trigger circuit (One-Shot Circuit) 218.Protection start unit 215 coupled low current comparative unit 226 and protected location 220.Cross low current comparative unit 226 received current feedback signal Cs and and cross low current reference signal Vucp.When the first power vd DH does not provide as yet to load 245, the accurate position of current feedback signal Cs is lower than an accurate position of crossing low current reference signal Vucp, and what made low current comparative unit 226 output high levles crosses low current guard signal UCP.The low current guard signal UCP that crosses of high levle oppositely becomes the low level signal through inverter 216, so single-shot trigger circuit 218 is kept the protection enabling signal of output low level, this moment, protected location 220 did not start.Therefore, when the first power vd DH does not provide as yet to load 245, controller 200 does not start defencive function, thereby can't operate in second pattern.

In case the first power vd DH provides to load 245; make accurate the accurate position that was higher than low current reference signal Vucp of current feedback signal Cs; cross the UCP of low current guard signal excessively of low current comparative unit 226 output low levels; oppositely become the high levle signal through inverter 216; so single-shot trigger circuit 218 will be kept the protection enabling signal of output high levle, protected location 220 begins to start defencive function.

After protected location 220 started, when the accurate position of current feedback signal Cs is lower than an accurate position of crossing low current reference signal Vucp again, the load current of the load 245 of promptly flowing through is lower than to be exported one again and crosses low current guard signal UCP when being scheduled to low current value.Cross 222 receptions one of low pressure comparative unit and cross a low pressure reference signal Vuvp and a voltage feedback signal Vs; voltage feedback signal Vs represents the size of the driving voltage of the first power vd DH; when the accurate position of voltage feedback signal Vs was lower than the accurate position of low pressure reference signal Vuvp, promptly the driving voltage of the first power vd DH was lower than when being scheduled to low voltage value output one and crosses low-voltage variation signal UVP.Cross high pressure ratio and receive a voltage feedback signal Vs and a too high pressure reference signal Vovp than unit 224; when the accurate position of voltage feedback signal Vs was higher than the accurate position of too high pressure reference signal Vovp, high pressure guard signal OVP was crossed in output one when promptly the driving voltage of the first power vd DH was higher than a predetermined too high voltages value.Excessive current comparative unit 228 received current feedback signal Cs and an excessive current reference signal Vocp; when the accurate position of current feedback signal Cs is higher than the accurate position of excessive current reference signal Vocp, when being higher than a predetermined excessive current value, exports the load current of the load 245 of promptly flowing through an excessive current guard signal OCP.When protected location 220 in a single day received low-voltage variation signal UVP, crossed high pressure guard signal OVP, when crossing low current guard signal UCP, excessive current guard signal OCP arbitrary; be output protection signal PROT with stop control 200 output control signal S2, make the first power vd DH no longer transmit electric power to load 245 till controller 200 is restarted.

Present embodiment also can cross low-voltage variation signal UVP, cross high pressure guard signal OVP, cross low current guard signal UCP, excessive current guard signal OCP or other arbitrary lasting generations in order to the protection detection signal of detecting drive circuit surpasses a scheduled time during length, and protected location 220 is output protection signal PROT; Perhaps; also can cross low-voltage variation signal UVP, cross high pressure guard signal OVP, when crossing low current guard signal UCP, excessive current guard signal OCP or other number of times and surpassing a pre-determined number in order to arbitrary generation of the protection detection signal of detecting drive circuit, the just output protection signal PROT circuit erroneous judgement of avoiding temporary transient circuit abnormality to cause of protected location 220.

In addition, at present embodiment, controller 200 judges by the state of detecting point A whether the first power vd DH provides to load 245.In practical application, controller 200 can also be detected any point that is coupled to driving power 250 and whether judge the first power vd DH to provide to load 245, for example some B shown in the 3rd figure or some C.

As mentioned above, the present invention meets patent three important documents fully: novelty, creativeness and practicality.The present invention discloses with preferred embodiment hereinbefore, and any those of ordinary skill is understandable that in the field of the invention, and this embodiment only is used to illustrate the present invention, and should not be read as restriction claim scope of the present invention.It should be noted that the variation and the modification of all and this embodiment equivalence all are covered by in the category of the present invention.Therefore, protection scope of the present invention should be as the criterion with claim.

Claims

1. light-emitting diode driving governor in order to control a LED driving circuit to drive a light-emitting diode (LED) module, is characterized in that:

One feedback control unit is exported a control signal to adjust this drive current according to the flow through current feedback signal of a drive current size of this light-emitting diode (LED) module of representative; And

Whether one protected location produces a guard signal according to this current feedback signal with decision, exports this drive current and is restarted until this light-emitting diode driving governor to stop this LED driving circuit.

2. light-emitting diode driving governor as claimed in claim 1 is characterized in that more comprising a protection start unit, whether starts this protected location according to this current feedback signal with decision.

3. light-emitting diode driving governor as claimed in claim 2 is characterized in that this light-emitting diode driving governor couples one first power supply, and this LED driving circuit couples a second source.

4. light-emitting diode driving governor as claimed in claim 3; it is characterized in that this protected location more receives a voltage feedback signal of representing the driving voltage size that this LED driving circuit provides; and in whether producing this guard signal with decision, export this drive current and restarted until this light-emitting diode driving governor to stop this LED driving circuit according to this voltage feedback signal.

5. as claim 3 or 4 described light-emitting diode driving governors; it is characterized in that this protected location is higher than one first magnitude of voltage or is lower than one second magnitude of voltage or when this drive current is higher than one first current value or is lower than one second current value, produces this guard signal in this driving voltage.

6. as claim 3 or 4 described light-emitting diode driving governors; it is characterized in that this protected location counts this driving voltage and be higher than the number of times of this first magnitude of voltage or be lower than the number of times of this second magnitude of voltage or this drive current is higher than the number of times of one first current value or is lower than the number of times of one second current value; during greater than a pre-determined number value, produce this guard signal in arbitrary numerical value of those number of times.

7. as claim 3 or 4 described light-emitting diode driving governors; it is characterized in that this protected location is higher than one first magnitude of voltage or is lower than one second magnitude of voltage in this driving voltage continues a scheduled time and is higher than one first current value or is lower than one second current value during length or in this drive current and continue a scheduled time during length, produces this guard signal.

8. drive circuit in order to drive a load, is characterized in that:

One driving power is in order to provide one first power supply to drive this load; And

One controller couples a second source receiving the operation required electric power, and the electric power size of this load is provided and provides this load electric in order to stop this driving power during in one second pattern in order to control this driving power when one first pattern;

Wherein, this controller is before this driving power provides this first power supply, and quiescing is in this second pattern.

9. drive circuit as claimed in claim 8, it is characterized in that this controller detects a flow through drive current of this load of a driving voltage of this first power supply or detecting, and when in a single day this driving voltage is higher than one first magnitude of voltage or is lower than one second magnitude of voltage or when in a single day this drive current is higher than one first current value or is lower than one second current value, enter this second pattern.

10. drive circuit as claimed in claim 8, it is characterized in that this controller detects a flow through drive current of this load of a driving voltage of this first power supply or detecting, and count this driving voltage and be higher than the number of times of this first magnitude of voltage or be lower than the number of times of this second magnitude of voltage or write down the number of times that this drive current is higher than the number of times of this first current value or is lower than this second current value, in case during greater than a pre-determined number value, enter this second pattern in those number of times arbitrary.

11. LED driving circuit as claimed in claim 8, it is characterized in that this controller detects a flow through drive current of this load of a driving voltage of this first power supply or detecting, and in a single day be higher than one first magnitude of voltage or be lower than one second magnitude of voltage in this driving voltage and continue a scheduled time and in a single day be higher than one first current value or be lower than one second current value during length or in this drive current and continue a scheduled time during length, enter this second pattern.

12. drive circuit as claimed in claim 8 is characterized in that this load comprises a light-emitting diode.

13. drive circuit as claimed in claim 12 is characterized in that this controller receives a dim signal, and controls the time that this driving power provides this load electric according to this dim signal.